Chapter 031. Pharyngitis, Sinusitis, Otitis, and Other Upper Respiratory Tract Infections
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Harrison's Internal Medicine > Chapter 31. Pharyngitis, Sinusitis, Otitis, and Other Upper Respiratory Tract Infections
Pharyngitis, Sinusitis, Otitis, and Other Upper Respiratory Tract Infections: Introduction
Infections of the upper respiratory tract (URIs) have a tremendous impact on public health. They are among the most common reasons for visits to primary care providers, and, although the illnesses are typically mild, their high incidence and transmission rates place them among the leading causes of time lost from work or school. Even though the minority (~25%) of cases are caused by bacteria, URIs are the leading diagnoses for which antibiotics are prescribed on an outpatient basis in the United States. The enormous consumption of antibiotics for these illnesses has contributed to the rise in antibiotic resistance among common community-acquired pathogens such as Streptococcus pneumoniae—a trend that in itself has had an enormous influence on public health.
Although most URIs are caused by viruses, distinguishing patients with primary viral infection from those with primary bacterial infection is difficult. Signs and symptoms of bacterial and viral URIs are, in fact, indistinguishable. Because routine, rapid testing is neither available nor practical for most syndromes, acute infections are diagnosed largely on clinical grounds. Thus the judicious use of antibiotics in this setting is challenging.
Nonspecific Infections of the Upper Respiratory Tract
Nonspecific URIs are a broadly defined group of disorders that collectively constitute the leading cause of ambulatory care visits in the United States. By definition, nonspecific URIs have no prominent localizing features. They are identified by a variety of descriptive names, including acute infective rhinitis, acute rhinopharyngitis/nasopharyngitis, acute coryza, and acute nasal catarrh, as well as by the inclusive label common cold.
The large assortment of URI classifications reflects the wide variety of causative infectious agents and the varied manifestations of common pathogens. Nearly all nonspecific URIs are caused by viruses spanning multiple virus families and many antigenic types. For instance, there are at least 100 immunotypes of rhinovirus (Chap. 179), the most common cause of URI (~30–40% of cases); other causes include influenza virus (three immunotypes; Chap. 180) as well as parainfluenza virus (four immunotypes), coronavirus (at least three immunotypes), and adenovirus (47 immunotypes) (Chap. 179). Respiratory syncytial virus (RSV) also accounts for a small percentage of cases each year, as do some viruses not typically associated with URIs (e.g., enteroviruses, rubella virus, and varicella-zoster virus). Even with sophisticated diagnostic and culture techniques, a substantial proportion (25–30%) of cases have no assigned pathogen.
The signs and symptoms of nonspecific URI are similar to those of other URIs but lack a pronounced localization to one particular anatomic location, such as the sinuses, pharynx, or lower airway. Nonspecific URI is commonly described as an acute, mild, and self-limited catarrhal syndrome, with a median duration of ~1 week. Signs and symptoms are diverse and frequently variable across patients. The principal signs and symptoms of nonspecific URI include rhinorrhea (with or without purulence), nasal congestion, cough, and sore throat. Other manifestations, such as fever, malaise, sneezing, and hoarseness, are more variable, with fever more common among infants and young children. Occasionally, clinical features reflect the underlying viral pathogen; myalgias and fatigue, for example, are sometimes seen with influenza and parainfluenza infections, while conjunctivitis may suggest infection with adenovirus or enterovirus. Findings on physical examination are frequently nonspecific and unimpressive. Between 0.5 and 2% of colds are complicated by secondary bacterial infections (e.g., rhinosinusitis, otitis media, and pneumonia), particularly in high-risk populations such as infants, elderly persons, and chronically ill patients. Secondary bacterial infections are usually associated with a prolonged course of illness, increased severity of illness, and localization of signs and symptoms. Purulent secretions from the nares or throat have often been used as an indication of sinusitis or pharyngitis. However, these secretions are also seen in nonspecific URI and, in the absence of other clinical features, are poor predictors of bacterial infection.
Upper Respiratory Infections: Treatment
Antibiotics have no role in the treatment of uncomplicated nonspecific URI. In the absence of clinical evidence of bacterial infection, treatment remains entirely symptom-based, with use of decongestants and nonsteroidal anti-inflammatory drugs. Other therapies directed at specific symptoms are often useful, including dextromethorphan for cough and lozenges with topical anesthetic for sore throat. Clinical trials of zinc, vitamin C, echinacea, and other alternative remedies have revealed no consistent benefit for the treatment of nonspecific URI.
Infections of the Sinus
Sinusitis refers to an inflammatory condition involving the four paired structures surrounding the nasal cavities. Although most cases of sinusitis involve more than one sinus, the maxillary sinus is most commonly involved; next in frequency are the ethmoid, frontal, and sphenoid sinuses. Each sinus is lined with a respiratory epithelium that produces mucus, which is transported out by ciliary action through the sinus ostium and into the nasal cavity. Normally, mucus does not accumulate in the sinuses, which remain sterile despite their adjacency to the bacterium-filled nasal passages. When the sinus ostia are obstructed, however, or when ciliary clearance is impaired or absent, the secretions can be retained, producing the typical signs and symptoms of sinusitis. The retained secretions may become infected with a variety of pathogens, including viruses, bacteria, and fungi. Sinusitis affects a tremendous proportion of the population, accounts for millions of visits to primary care physicians each year, and is the fifth leading diagnosis for which antibiotics are prescribed. It is typically classified by duration of illness (acute vs. chronic); by etiology (infectious vs. noninfectious); and, when infectious, by the offending pathogen type (viral, bacterial, or fungal).
Acute sinusitis—defined as sinusitis of <4 weeks' duration—constitutes the vast majority of sinusitis cases. Most cases are diagnosed in the ambulatory care setting and occur primarily as a consequence of a preceding viral URI. Differentiating acute bacterial and viral sinusitis on clinical grounds is difficult. Therefore, it is perhaps unsurprising that antibiotics are prescribed frequently (in 85–98% of all cases) for this condition.
A number of infectious and noninfectious factors can contribute to acute obstruction of the sinus ostia or impairment of ciliary clearance, with consequent sinusitis. Noninfectious causes include allergic rhinitis (with either mucosal edema or polyp obstruction), barotrauma (e.g., from deep-sea diving or air travel), or chemical irritants. Illnesses such as nasal and sinus tumors (e.g., squamous cell carcinoma) or granulomatous diseases (e.g., Wegener's granulomatosis or rhinoscleroma) can also produce obstruction of the sinus ostia, while conditions leading to altered mucus content (e.g., cystic fibrosis) can cause sinusitis through impaired mucus clearance. In the hospital setting, nasotracheal intubation is a major risk factor for nosocomial sinusitis in intensive care units.
Acute infectious sinusitis can be caused by a variety of organisms, including viruses, bacteria, and fungi. Viral rhinosinusitis is far more common than bacterial sinusitis, although relatively few studies have sampled sinus aspirates for the presence of different viruses. In those studies that have done so, the viruses most commonly isolated—both alone and with bacteria—have been rhinovirus, parainfluenza virus, and influenza virus. Bacterial causes of sinusitis have been better described. Among community-acquired cases, S. pneumoniae and nontypable Haemophilus influenzae are the most common pathogens, accounting for 50–60% of cases. Moraxella catarrhalis causes disease in a significant percentage (20%) of children but less often in adults. Other streptococcal species and Staphylococcus aureus cause only a small percentage of cases, although there is increasing concern about community strains of methicillin-resistant S. aureus (MRSA) as an emerging cause. Anaerobes are occasionally found in association with infections of the roots of premolar teeth that spread into the adjacent maxillary sinuses. The role of Chlamydophila pneumoniae and Mycoplasma pneumoniae in the pathogenesis of acute sinusitis is still unclear. Nosocomial cases are commonly associated with bacteria found in the hospital environment, including S. aureus, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumoniae, and Enterobacter species. Often, these infections are polymicrobial and involve organisms that are highly resistant to numerous antibiotics. Fungi are also established causes of sinusitis, although most acute cases are in immunocompromised patients and represent invasive, life-threatening infections. The best-known example is rhinocerebral mucormycosis caused by fungi of the order Mucorales, which includes Rhizopus, Rhizomucor, Mucor, Absidia, and Cunninghamella. These infections usually occur in diabetic patients with ketoacidosis but also develop in transplant recipients, patients with hematologic malignancies, and patients receiving chronic glucocorticoid or deferoxamine therapy. Other hyaline molds, such as Aspergillus and Fusarium species, are also occasional causes of this disease.
Most cases of acute sinusitis present after or in conjunction with a viral URI, and it can be difficult to discriminate the clinical features of one from the other. A large proportion of patients with colds have sinus inflammation, although bacterial sinusitis complicates only 0.2–2% of these viral infections. Common presenting symptoms of sinusitis include nasal drainage and congestion, facial pain or pressure, and headache. Thick, purulent or discolored nasal discharge is often thought to indicate bacterial sinusitis but also occurs early in viral infections such as the common cold and is not specific to bacterial infection. Other nonspecific manifestations include cough, sneezing, and fever. Tooth pain, most often involving the upper molars, is associated with bacterial sinusitis, as is halitosis.
In acute sinusitis, sinus pain or pressure often localizes to the involved sinus (particularly the maxillary sinus) and can be worse when the patient bends over or is supine. Although rare, manifestations of advanced sphenoid or ethmoid sinus infection can be profound, including severe frontal or retroorbital pain radiating to the occiput, thrombosis of the cavernous sinus, and signs of orbital cellulitis. Acute focal sinusitis is uncommon but should be considered in the patient with severe symptoms over the maxillary sinus and fever, regardless of illness duration. Similarly, advanced frontal sinusitis can present with a condition known as Pott's puffy tumor, with soft tissue swelling and pitting edema over the frontal bone from a communicating subperiosteal abscess. Life-threatening complications include meningitis, epidural abscess, and cerebral abscess.
Patients with acute fungal sinusitis (such as mucormycosis) often present with symptoms related to pressure effects, particularly when the infection has spread to the orbits and cavernous sinus. Signs such as orbital swelling and cellulitis, proptosis, ptosis, and decreased extraocular movement are common, as is retroorbital or periorbital pain. Nasopharyngeal ulcerations, epistaxis, and headaches are also frequent, and involvement of cranial nerves V and VII has been described in more advanced cases. Bony erosion may be evident on examination. Oftentimes, the patient does not appear seriously ill despite the rapidly progressive nature of these infections.
Patients with acute nosocomial sinusitis are often critically ill and thus do not manifest the typical clinical features of sinus disease. This diagnosis should be suspected, however, when hospitalized patients who have appropriate risk factors (e.g., nasotracheal intubation) develop fever of unknown origin.
Distinguishing viral from bacterial sinusitis in the ambulatory setting is usually difficult, given the relatively low sensitivity and specificity of the common clinical features. One clinical feature that has been used to help guide diagnostic and therapeutic decision-making is illness duration. Because acute bacterial sinusitis is uncommon in patients whose symptoms have lasted <7 days, several authorities now recommend reserving this diagnosis for patients with "persistent" symptoms (i.e., symptoms lasting >7 days in adults or >10–14 days in children) accompanied by purulent nasal discharge (Table 31-1). Even among the patients who meet these criteria, only 40–50% have true bacterial sinusitis. The use of CT or sinus radiography is not recommended for routine cases, particularly early in the course of illness (i.e., at <7 days), given the high prevalence of similar abnormalities among cases of acute viral rhinosinusitis. In the evaluation of persistent, recurrent, or chronic sinusitis, CT of the sinuses is the radiographic study of choice.
Table 31-1 Guidelines for the Diagnosis and Treatment of Acute Sinusitis
Age Group Diagnostic Criteria Treatment Recommendationsa
Adults Moderate symptoms (e.g., nasal purulence/ congestion or cough) for >7 d or Initial therapy Severe symptoms of any duration, including unilateral/focal facial swelling or tooth pain Amoxicillin, 500 mg PO tid or 875 mg PO bid, or TMP-SMX, 1 DS tablet PO bid for 10–14 d Exposure to antibiotics within 30 d or >30% prevalence of penicillin-resistant S. pneumoniae Amoxicillin, 1000 mg PO tid, or Amoxicillin/clavulanate (extended release), 2000 mg PO bid, or Antipneumococcal fluoroquinolone (e.g., levofloxacin, 500 mg PO qd) Recent treatment failure Amoxicillin/clavulanate (extended release), 2000 mg PO bid, or Amoxicillin, 1500 mg bid, plus clindamycin, 300 mg PO qid, or Antipneumococcal fluoroquinolone (e.g., levofloxacin, 500 mg PO qd) Children Moderate symptoms (e.g., nasal purulence/congestion or cough) for >10–14 d or Initial therapy Severe symptoms of any duration, including fever (>102°F), unilateral/focal facial swelling or pain Amoxicillin, 45–90 mg/kg qd (up to 2 g) PO in divided doses (bid or tid), or Cefuroxime axetil, 30 mg/kg qd PO in divided doses (bid), or Cefdinir, 14 mg/kg PO qd Exposure to antibiotics within 30 d, recent treatment failure, or >30% prevalence of penicillin-resistant S. pneumoniae Amoxicillin, 90 mg/kg qd (up to 2 g) PO in divided doses (bid), plus clavulanate, 6.4 mg/kg qd PO in divided doses (bid) (extra-strength suspension), or Cefuroxime axetil, 30 mg/kg qd PO in divided doses (bid), or Cefdinir, 14 mg/kg PO qd
aUnless otherwise specified, the duration of therapy is generally 10 d, with appropriate follow-up.
Note: DS, double-strength; TMP-SMX, trimethoprim-sulfamethoxazole.
Sources: American Academy of Pediatrics Subcommittee on Management of Sinusitis and Committee on Quality Improvement, 2001; Hickner et al, 2001; Piccirillo, 2004; and Sinus and Allergy Health Partnership, 2004.
The clinical history and/or setting can often identify cases of acute anaerobic bacterial sinusitis, acute fungal sinusitis, or sinusitis from noninfectious causes (e.g., allergic rhinosinusitis). In the case of an immunocompromised patient with acute fungal sinus infection, immediate examination by an otolaryngologist is required. Biopsy specimens from involved areas should be examined by a pathologist for evidence of fungal hyphal elements and tissue invasion. Cases of suspected acute nosocomial sinusitis should be confirmed by sinus CT. Because therapy should target the offending organism, a sinus aspirate should be obtained, if possible, for culture and susceptibility testing.
Acute Sinusitis: Treatment
Most patients with a diagnosis of acute rhinosinusitis based on clinical grounds improve without antibiotic therapy. The preferred initial approach in patients with mild to moderate symptoms of short duration is therapy aimed at facilitating sinus drainage, such as oral and topical decongestants, nasal saline lavage, and—in patients with a history of chronic sinusitis or allergies—nasal glucocorticoids. Adult patients who do not improve after 7 days, children who do not improve after 10–14 days, and patients with more severe symptoms (regardless of duration) should be treated with antibiotics (Table 31-1). Empirical therapy should consist of the narrowest-spectrum agent active against the most common bacterial pathogens, including S. pneumoniae and H. influenzae—e.g., amoxicillin. No clinical trials support the use of broad-spectrum agents for routine cases of bacterial sinusitis, even in the current era of drug-resistant S. pneumoniae. Up to 10% of patients do not respond to initial antimicrobial therapy; sinus aspiration and/or lavage by an otolaryngologist should be considered in these cases. Antibiotic prophylaxis to prevent episodes of recurrent acute bacterial sinusitis is not recommended.
Surgical intervention and IV antibiotic administration are usually reserved for patients with severe disease or those with intracranial complications, such as abscess or orbital involvement. Immunocompromised patients with acute invasive fungal sinusitis usually require extensive surgical debridement and treatment with IV antifungal agents active against fungal hyphal forms, such as amphotericin B. Specific therapy should be individualized according to the fungal species and the individual patient's characteristics.
Treatment of nosocomial sinusitis should begin with broad-spectrum antibiotics to cover common pathogens such as S. aureus and gram-negative bacilli. Therapy should then be tailored to the results of culture and susceptibility testing of sinus aspirates.
Chronic sinusitis is characterized by symptoms of sinus inflammation lasting >12 weeks. This illness is most commonly associated with either bacteria or fungi, and clinical cure in most cases is very difficult. Many patients have undergone treatment with repeated courses of antibacterial agents and multiple sinus surgeries, increasing their risk of colonization with antibiotic-resistant pathogens and of surgical complications. Patients often suffer significant morbidity, sometimes over many years.
In chronic bacterial sinusitis , infection is thought to be due to the impairment of mucociliary clearance from repeated infections rather than to persistent bacterial infection. However, the pathogenesis of this condition is poorly understood. Although certain conditions (e.g., cystic fibrosis) can predispose patients to chronic bacterial sinusitis, most patients with this infection do not have obvious underlying conditions that result in the obstruction of sinus drainage, the impairment of ciliary action, or immune dysfunction. Patients experience constant nasal congestion and sinus pressure, with intermittent periods of greater severity, which may persist for years. CT can be helpful in determining the extent of disease and the response to therapy. The management team should include an otolaryngologist to conduct endoscopic examinations and obtain tissue samples for histologic examination and culture.
Chronic fungal sinusitis is a disease of immunocompetent hosts and is usually noninvasive, although slowly progressive invasive disease is sometimes seen. Noninvasive disease, which is typically associated with hyaline molds such as Aspergillus species and dematiaceous molds such as Curvularia or Bipolaris species, can present as a number of different scenarios. In mild, indolent disease, which usually occurs in the setting of repeated failures of antibacterial therapy, only nonspecific mucosal changes may be seen on sinus CT. Endoscopic surgery is usually curative in these patients, with no need for antifungal therapy. Another form of disease presents with long-standing, often unilateral symptoms and opacification of a single sinus on imaging studies as a result of a mycetoma (fungus ball) within the sinus. Treatment for this condition is also surgical, although systemic antifungal therapy may be warranted in the rare case where bony erosion occurs. A third form of disease, known as allergic fungal sinusitis, is seen in patients with a history of nasal polyposis and asthma, who often have had multiple sinus surgeries. Patients with this condition produce a thick, eosinophilic mucus with the consistency of peanut butter that contains sparse fungal hyphae on histologic examination. Patients often present with pansinusitis.
Chronic Sinusitis: Treatment
Treatment of chronic bacterial sinusitis can be challenging and consists primarily of repeated culture-guided courses of antibiotics, sometimes for 3–4 weeks at a time; administration of intranasal glucocorticoids; and mechanical irrigation of the sinus with sterile saline solution. When this management approach fails, sinus surgery may be indicated and sometimes provides significant, albeit short-term, alleviation. Treatment of chronic fungal sinusitis consists of surgical removal of impacted mucus. Recurrence, unfortunately, is common.
Infections of the Ear and Mastoid
Infections of the ear and associated structures can involve both the middle and external ear, including the skin, cartilage, periosteum, ear canal, and tympanic and mastoid cavities. Both viruses and bacteria are known causes of these infections, some of which result in significant morbidity if not treated appropriately.
Infections of the External Ear Structures
Infections involving the structures of the external ear are often difficult to differentiate from noninfectious inflammatory conditions with similar clinical manifestations. Clinicians should consider inflammatory disorders as a possible cause of external ear irritation, particularly in the absence of local or regional adenopathy. Aside from the more salient causes of inflammation such as trauma, insect bite, and overexposure to sunlight or extreme cold, the differential diagnosis should include less common conditions such as autoimmune disorders (e.g., lupus or relapsing polychondritis) and vasculitides (e.g., Wegener's granulomatosis).
Auricular cellulitis is an infection of the skin overlying the external ear and typically follows minor local trauma. It presents with the typical signs and symptoms of a skin/soft tissue infection, with tenderness, erythema, swelling, and warmth of the external ear (particularly the lobule) but without apparent involvement of the ear canal or inner structures. Treatment consists of warm compresses and oral antibiotics such as dicloxacillin that are active against typical skin and soft tissue pathogens (specifically, S. aureus and streptococci). IV antibiotics, such as a first-generation cephalosporin (e.g., cefazolin) or a penicillinase-resistant penicillin (e.g., nafcillin), are occasionally needed for more severe cases.
Perichondritis, an infection of the perichondrium of the auricular cartilage, typically follows local trauma (e.g., ear piercing, burns, or lacerations). Occasionally, when the infection spreads down to the cartilage of the pinna itself, patients may also have chondritis. The infection may closely resemble auricular cellulitis, with erythema, swelling, and extreme tenderness of the pinna, although the lobule is less often involved in perichondritis. The most common pathogens are P. aeruginosa and S. aureus, although other gram-negative and gram-positive organisms are occasionally involved. Treatment consists of systemic antibiotics active against both P. aeruginosa and S. aureus. An antipseudomonal penicillin (e.g., piperacillin) or a combination of a penicillinase-resistant penicillin plus an antipseudomonal quinolone (e.g., nafcillin plus ciprofloxacin) is typically used. Incision and drainage may be helpful for culture and for resolution of infection, which often takes weeks. When perichondritis fails to respond to adequate antimicrobial therapy, clinicians should consider a noninfectious inflammatory etiology; for example, relapsing polychondritis is often mistaken for infectious perichondritis.
The term otitis externa refers to a collection of diseases involving primarily the auditory meatus. Otitis externa usually results from a combination of heat, retained moisture, and desquamation and maceration of the epithelium of the outer ear canal. The disease exists in several forms: localized, diffuse, chronic, and invasive. All forms are predominantly bacterial in origin, with P. aeruginosa and S. aureus the most common pathogens.
Acute localized otitis externa (furunculosis) can develop in the outer third of the ear canal, where skin overlies cartilage and hair follicles are numerous. As in furunculosis elsewhere on the body, S. aureus is the usual pathogen, and treatment typically consists of an oral antistaphylococcal penicillin (e.g., dicloxacillin), with incision and drainage in cases of abscess formation.
Acute diffuse otitis externa is also known as swimmer's ear, although it can develop in patients who have not recently been swimming. Heat, humidity, and the loss of protective cerumen lead to excessive moisture and elevation of the pH in the ear canal, which in turn lead to skin maceration and irritation. Infection may then occur; the predominant pathogen is P. aeruginosa, although other gram-negative and gram-positive organisms have been recovered from patients with this condition. The illness often starts with itching and progresses to severe pain, which is usually triggered by manipulation of the pinna or tragus. The onset of pain is generally accompanied by the development of an erythematous, swollen ear canal, often with scant white, clumpy discharge. Treatment consists of cleansing the canal to remove debris and to enhance the activity of topical therapeutic agents—usually hypertonic saline or mixtures of alcohol and acetic acid. Inflammation can also be decreased by adding glucocorticoids to the treatment regimen or by using Burow's solution (aluminum acetate in water). Antibiotics are most effective when given topically. Otic mixtures provide adequate pathogen coverage; these preparations usually combine neomycin with polymyxin, with or without glucocorticoids.
Chronic otitis externa is caused primarily by repeated local irritation, most commonly arising from persistent drainage from a chronic middle-ear infection. Other causes of repeated irritation, such as insertion of cotton swabs or other foreign objects into the ear canal, can lead to this condition, as can rare chronic infections such as syphilis, tuberculosis, or leprosy. Chronic otitis externa typically presents as erythematous, scaling dermatitis in which the predominant symptom is pruritus rather than pain; this condition must be differentiated from several others that produce a similar clinical picture, such as atopic dermatitis, seborrheic dermatitis, psoriasis, and dermatomycosis. Therapy consists of identifying and treating or removing the offending process, although successful resolution is frequently difficult.
Invasive otitis externa, also known as malignant or necrotizing otitis externa, is an aggressive and potentially life-threatening disease that occurs predominantly in elderly diabetic patients and other immunocompromised patients. The disease begins in the external canal, progresses slowly over weeks to months, and often is difficult to distinguish from a severe case of chronic otitis externa because of the presence of purulent otorrhea and an erythematous swollen ear and external canal. Severe, deep-seated otalgia is often noted and can help differentiate invasive from chronic otitis externa. The characteristic finding on examination is granulation tissue in the posteroinferior wall of the external canal, near the junction of bone and cartilage. If left unchecked, the infection can migrate to the base of the skull (resulting in skull-base osteomyelitis) and on to the meninges and brain, with a high associated mortality rate. Cranial nerve involvement is occasionally seen, with the facial nerve usually affected first and most often. Thrombosis of the sigmoid sinus can occur if the infection extends to that area. CT, which can reveal osseous erosion of the temporal bone and skull base, can be used to help determine the extent of disease, as can gallium and technetium-99 scintigraphy studies. P. aeruginosa is by far the most common pathogen, although S. aureus, Staphylococcus epidermidis, Aspergillus, Actinomyces, and some gram-negative bacteria have also been associated with this disease. In all cases, the external ear canal should be cleansed and a biopsy specimen of the granulation tissue within the canal (or of deeper tissues) should be obtained for culture of the offending organism. IV antibiotic therapy is directed specifically toward the recovered pathogen. For P. aeruginosa, the regimen typically includes an antipseudomonal penicillin or cephalosporin (e.g., piperacillin or ceftazidime) with an aminoglycoside. A fluoroquinolone antibiotic is frequently used in place of the aminoglycoside and can even be administered orally, given the excellent bioavailability of this drug class. In addition, antibiotic drops containing an agent active against Pseudomonas (e.g., ciprofloxacin) are usually prescribed and are combined with glucocorticoids to reduce inflammation. Cases of invasive Pseudomonas otitis externa recognized in the early stages can sometimes be treated with oral and otic fluoroquinolones alone, albeit with close follow-up. Extensive surgical debridement, once an important component of the treatment approach, is now rarely indicated.
Infections of Middle-Ear Structures
Otitis media is an inflammatory condition of the middle ear that results from dysfunction of the eustachian tube in association with a number of illnesses, including URIs and chronic rhinosinusitis. The inflammatory response to these conditions leads to the development of a sterile transudate within the middle-ear and mastoid cavities. Infection may occur if bacteria or viruses from the nasopharynx contaminate this fluid, producing an acute (or sometimes chronic) illness.
Acute Otitis Media
Acute otitis media results when pathogens from the nasopharynx are introduced into the inflammatory fluid collected in the middle ear (e.g., by nose blowing during a URI). The proliferation of these pathogens in this space leads to the development of the typical signs and symptoms of acute middle-ear infection. The diagnosis of acute otitis media requires the demonstration of fluid in the middle ear (with tympanic membrane immobility) and the accompanying signs or symptoms of local or systemic illness (Table 31-2).
Table 31-2 Guidelines for the Diagnosis and Treatment of Acute Otitis Media
Illness Severity Diagnostic Criteria Treatment Recommendations Mild to moderate Fluid in the middle ear, evidenced by decreased tympanic membrane mobility, air/fluid level behind tympanic membrane, bulging tympanic membrane, purulent otorrhea
Acute onset of signs and symptoms of middle-ear inflammation, including fever, otalgia, decreased hearing, tinnitus, vertigo, erythematous tympanic membrane
Observation alone (symptom relief only)b
Amoxicillin, 80–90 mg/kg qd (up to 2 g) PO in divided doses (bid or tid),
Cefdinir, 14 mg/kg qd PO in 1 dose or divided doses (bid), or
Cefuroxime, 30 mg/kg qd PO in divided doses (bid),
Azithromycin, 10 mg/kg qd PO on day 1 followed by 5 mg/kg qd PO for 4 d
Exposure to antibiotics within 30 d or recent treatment failurea,c
Amoxicillin, 90 mg/kg qd (up to 2 g) PO in divided doses (bid), plus clavulanate, 6.4 mg/kg qd PO in divided doses (bid), or
Ceftriaxone, 50 mg/kg IV/IM qd for 3 d, or
Clindamycin, 30–40 mg/kg qd PO in divided doses (tid)
Severe As above, with temperature ≥39.0°C
Moderate to severe otalgia
Amoxicillin, 90 mg/kg qd (up to 2 g) PO in divided doses (bid), plus clavulanate, 6.4 mg/kg qd PO in divided doses (bid),
Ceftriaxone, 50 mg/kg IV/IM qd for 3 d
Exposure to antibiotics within 30 d or recent treatment failurea,c
Ceftriaxone, 50 mg/kg IV/IM qd for 3 d, or
Clindamycin, 30–40 mg/kg qd PO in divided doses (tid), or
Consider tympanocentesis with culture
aDuration (unless otherwise specified): 10 d for patients <6 years old and patients with severe disease; 5–7 d (with consideration of observation only in previously healthy individuals with mild disease) for patients ≥6 years old.
bObservation (deferring antibacterial treatment for 48–72 h and limiting management to symptom relief) is an option for mild to moderate disease in children 6 months to 2 years of age with an uncertain diagnosis and for children ≥2 years of age.
cFailure to improve and/or clinical worsening after 48–72 h of observation or treatment.
Sources: American Academy of Pediatrics Subcommittee on Management of Acute Otitis Media, 2004; Dowell et al, 1998.
Acute otitis media typically follows a viral URI. The causative viruses (most commonly RSV, influenza virus, rhinovirus, and enterovirus) can themselves cause subsequent acute otitis media; more often, they predispose the patient to bacterial otitis media. Studies using tympanocentesis have consistently found S. pneumoniae to be the most important bacterial cause, isolated in up to 35% of cases. H. influenzae (nontypable strains) and M. catarrhalis are also common bacterial causes of acute otitis media, and concern is increasing about community strains of MRSA as an emerging etiologic agent. Viruses, such as those mentioned above, have been recovered either alone or with bacteria in 17–40% of cases.
Fluid in the middle ear is typically demonstrated or confirmed with pneumatic otoscopy. In the absence of fluid, the tympanic membrane moves visibly with the application of positive and negative pressure, but this movement is dampened when fluid is present. With bacterial infection, the tympanic membrane can also be erythematous, bulging, or retracted and occasionally can spontaneously perforate. The signs and symptoms accompanying infection can be local or systemic, including otalgia, otorrhea, diminished hearing, fever, or irritability. Erythema of the tympanic membrane is often evident but is nonspecific as it is frequently seen in association with inflammation of the upper respiratory mucosa (e.g., during examination of young children). Other signs and symptoms that are occasionally reported include vertigo, nystagmus, and tinnitus.
Acute Otitis Media: Treatment
There has been considerable debate on the usefulness of antibiotics for the treatment of acute otitis media. Although most cases resolve clinically 1 week after the onset of illness, antibiotics appear to be of some benefit. A higher proportion of treated than of untreated patients are free of illness 3–5 days after diagnosis. The difficulty of predicting which patients will benefit from antibiotic therapy has led to different approaches. In the Netherlands, for instance, physicians typically manage acute otitis media with initial observation, administering anti-inflammatory agents for aggressive pain management and reserving antibiotics for high-risk patients, patients with complicated disease, or patients who do not improve after 48–72 h. In contrast, many experts in the United States continue to recommend antibiotic therapy for children <6 months old in light of the higher frequency of secondary complications in this young and functionally immunocompromised population. However, observation without antimicrobial therapy is now generally considered a reasonable option in the United States for mild to moderate disease in children 6 months to 2 years of age with an uncertain diagnosis and for children ≥2 years of age (Table 31-2).
Given that most studies of the etiologic agents of acute otitis media consistently document similar pathogen profiles, therapy is generally empirical except in those few cases where tympanocentesis is warranted—e.g., cases in newborns, cases refractory to therapy, and cases in patients who are severely ill or immunodeficient. Despite resistance to penicillin and amoxicillin in roughly one-quarter of S. pneumoniae isolates, one-third of H. influenzae isolates, and nearly all M. catarrhalis isolates, outcome studies continue to find that amoxicillin is as successful as any other agent, and it remains the drug of first choice in recommendations from multiple sources (Table 31-2). Therapy for uncomplicated acute otitis media is typically administered for 5–7 days to patients ≥6 years old; longer courses (e.g., 10 days) should be reserved for children <6 years old and patients with severe disease, in whom short-course therapy may be inadequate.
A switch in regimen is recommended if there is no clinical improvement by the third day of therapy, given the possibility of infection with a β-lactamase-producing strain of H. influenzae or M. catarrhalis or with a strain of penicillin-resistant S. pneumoniae. Decongestants and antihistamines are frequently used as adjunctive agents to reduce congestion and relieve obstruction of the eustachian tube, but clinical trials have yielded no significant evidence of benefit with either class of agents.
Recurrent Acute Otitis Media
Recurrent acute otitis media (more than three episodes within 6 months or four episodes within 12 months) is generally due to relapse or reinfection, although data indicate that the majority of early recurrences are new infections. In general, the same pathogens responsible for acute otitis media cause recurrent disease; even so, the recommended treatment consists of antibiotics active against β-lactamase-producing organisms. Antibiotic prophylaxis [e.g., with trimethoprim-sulfamethoxazole (TMP-SMX) or amoxicillin] can reduce recurrences in patients with recurrent acute otitis media by an average of one episode per year, but this benefit is small compared with the cost of the drug and the high likelihood of colonization with antibiotic-resistant pathogens. Other approaches, including placement of tympanostomy tubes, adenoidectomy, and tonsillectomy plus adenoidectomy, are of questionable overall value, given the relatively small benefit compared with the potential for complications.[newpage]
Serous Otitis Media
In serous otitis media (otitis media with effusion), fluid is present in the middle ear for an extended period and in the absence of signs and symptoms of infection. In general, acute effusions are self-limited; most resolve in 2–4 weeks. In some cases, however (in particular after an episode of acute otitis media), effusions can persist for months. These chronic effusions are often associated with a significant hearing loss in the affected ear. In younger children, persistent effusions and decreased hearing can be associated with impairment of language acquisition skills. The great majority of cases of otitis media with effusion resolve spontaneously within 3 months without antibiotic therapy. Antibiotic therapy or myringotomy with insertion of tympanostomy tubes is typically reserved for patients in whom bilateral effusion (1) has persisted for at least 3 months and (2) is associated with significant bilateral hearing loss. With this conservative approach and the application of strict diagnostic criteria for acute otitis media and otitis media with effusion, it is estimated that 6–8 million courses of antibiotics could be avoided each year in the United States.
Chronic Otitis Media
Chronic suppurative otitis media is characterized by persistent or recurrent purulent otorrhea in the setting of tympanic membrane perforation. Usually, there is also some degree of conductive hearing loss. This condition can be categorized as active or inactive. Inactive disease is characterized by a central perforation of the tympanic membrane, which allows drainage of purulent fluid from the middle ear. When the perforation is more peripheral, squamous epithelium from the auditory canal may invade the middle ear through the perforation, forming a mass of keratinaceous debris (cholesteatoma) at the site of invasion. This mass can enlarge and has the potential to erode bone and promote further infection, which can lead to meningitis, brain abscess, or paralysis of cranial nerve VII. Treatment of chronic active otitis media is surgical; mastoidectomy, myringoplasty, and tympanoplasty can be performed as outpatient surgical procedures, with an overall success rate of ~80%. Chronic inactive otitis media is more difficult to cure, usually requiring repeated courses of topical antibiotic drops during periods of drainage. Systemic antibiotics may offer better cure rates, but their role in the treatment of this condition remains unclear.
Acute mastoiditis was relatively common among children before the introduction of antibiotics. Because the mastoid air cells connect with the middle ear, the process of fluid collection and infection is usually the same in the mastoid as in the middle ear. Early and frequent treatment of acute otitis media is most likely the reason that the incidence of acute mastoiditis has declined to only 1.2–2.0 cases per 100,000 person-years in countries with high prescribing rates for acute otitis media. In countries like the Netherlands, where antibiotics are used sparingly for acute otitis media, the incidence rate of acute mastoiditis is roughly twice that in countries like the United States. However, neighboring Denmark has a rate of acute mastoiditis similar to that in the Netherlands but an antibiotic-prescribing rate for acute otitis media more similar to that in the United States.
In typical acute mastoiditis, purulent exudate collects in the mastoid air cells (Fig. 31-1), producing pressure that may result in erosion of the surrounding bone and the formation of abscess-like cavities that are usually evident on CT. Patients typically present with pain, erythema, and swelling of the mastoid process along with displacement of the pinna, usually in conjunction with the typical signs and symptoms of acute middle-ear infection. Rarely, patients can develop severe complications if the infection tracks under the periosteum of the temporal bone to cause a subperiosteal abscess, erodes through the mastoid tip to cause a deep neck abscess, or extends posteriorly to cause septic thrombosis of the lateral sinus.
Acute mastoiditis. Axial CT image shows an acute fluid collection within the mastoid air cells on the left.
Purulent fluid should be cultured whenever possible to help guide antimicrobial therapy. Initial empirical therapy is usually directed against the typical organisms associated with acute otitis media, such as S. pneumoniae, H. influenzae, and M. catarrhalis. Some patients with more severe or prolonged courses of illness should be treated for infection with S. aureus and gram-negative bacilli (including Pseudomonas). Broad empirical therapy is usually narrowed once culture results become available. Most patients can be treated conservatively with IV antibiotics; surgery (cortical mastoidectomy) can be reserved for complicated cases and those in which conservative treatment has failed.
Infections of the Pharynx and Oral Cavity
Oropharyngeal infections range from mild, self-limited viral illnesses to serious, life-threatening bacterial infections. The most common presenting symptom is sore throat—one of the most frequent reasons for ambulatory care visits by both adults and children. Although sore throat is a symptom in many noninfectious illnesses as well, the overwhelming majority of patients with a new sore throat have acute pharyngitis of viral or bacterial etiology.
Millions of visits to primary care providers each year are for sore throat; the majority of cases of acute pharyngitis are caused by typical respiratory viruses. The most important source of concern is infection with group A β-hemolytic Streptococcus (S. pyogenes), which is associated with acute glomerulonephritis and acute rheumatic fever. The risk of rheumatic fever can be reduced by timely penicillin therapy.
A wide variety of organisms cause acute pharyngitis. The relative importance of the different pathogens can only be estimated, since a significant proportion of cases (~30%) have no identified cause. Together, respiratory viruses are the most common identifiable cause of acute pharyngitis, with rhinoviruses and coronaviruses accounting for large proportions of cases (~20% and at least 5%, respectively). Influenza virus, parainfluenza virus, and adenovirus also account for a measurable share of cases, the latter as part of the more clinically severe syndrome of pharyngoconjunctival fever. Other important but less common viral causes include herpes simplex virus (HSV) types 1 and 2, coxsackievirus A, cytomegalovirus (CMV), and Epstein-Barr virus (EBV). Acute HIV infection can present as acute pharyngitis and should be considered in high-risk populations.
Acute bacterial pharyngitis is typically caused by S. pyogenes, which accounts for ~5–15% of all cases of acute pharyngitis in adults; rates vary with the season and with utilization of the health care system. Group A streptococcal pharyngitis is primarily a disease of children 5–15 years of age; it is uncommon among children <3 years old, as is rheumatic fever. Streptococci of groups C and G account for a minority of cases, although these serogroups are nonrheumatogenic. The remaining bacterial causes of acute pharyngitis are seen infrequently (<1% each) but should be considered in appropriate exposure groups because of the severity of illness if left untreated; these etiologic agents include Neisseria gonorrhoeae, Corynebacterium diphtheriae, Corynebacterium ulcerans, Yersinia enterocolitica, and Treponema pallidum (in secondary syphilis). Anaerobic bacteria can also cause acute pharyngitis (Vincent's angina) and can contribute to more serious polymicrobial infections, such as peritonsillar or retropharyngeal abscess (see below). Atypical organisms such as M. pneumoniae and C. pneumoniae have been recovered from patients with acute pharyngitis; whether these agents are commensals or causes of acute infection is debatable.
Although the signs and symptoms accompanying acute pharyngitis are not reliable predictors of the etiologic agent, the clinical presentation occasionally suggests that one etiology is more likely than another. Acute pharyngitis due to respiratory viruses such as rhinovirus or coronavirus is usually not severe and is typically associated with a constellation of coryzal symptoms better characterized as nonspecific URI. Findings on physical examination are uncommon; fever is rare, and tender cervical adenopathy and pharyngeal exudates are not seen. In contrast, acute pharyngitis from influenza virus can be severe and is much more likely to be associated with fever as well as with myalgias, headache, and cough. The presentation of pharyngoconjunctival fever due to adenovirus infection is similar. Since pharyngeal exudate may be present on examination, this condition can be difficult to differentiate from streptococcal pharyngitis. However, adenoviral pharyngitis is distinguished by the presence of conjunctivitis in one-third to one-half of patients. Acute pharyngitis from primary HSV infection can also mimic streptococcal pharyngitis in some cases, with pharyngeal inflammation and exudate, but the presence of vesicles and shallow ulcers on the palate can help differentiate the two diseases. This HSV syndrome is distinct from pharyngitis caused by coxsackievirus (herpangina), which is associated with small vesicles that develop on the soft palate and uvula and then rupture to form shallow white ulcers. Acute exudative pharyngitis coupled with fever, fatigue, generalized lymphadenopathy, and (on occasion) splenomegaly is characteristic of infectious mononucleosis due to EBV or CMV. Acute primary infection with HIV is frequently associated with fever and acute pharyngitis as well as with myalgias, arthralgias, malaise, and occasionally a nonpruritic maculopapular rash, which later may be followed by lymphadenopathy and mucosal ulcerations without exudate.
The clinical features of acute pharyngitis caused by streptococci of groups A, C, and G are all similar, ranging from a relatively mild illness without many accompanying symptoms to clinically severe cases with profound pharyngeal pain, fever, chills, and abdominal pain. A hyperemic pharyngeal membrane with tonsillar hypertrophy and exudate is usually seen, along with tender anterior cervical adenopathy. Coryzal manifestations, including cough, are typically absent; when present, they suggest a viral etiology. Strains of S. pyogenes that generate erythrogenic toxin can also produce scarlet fever characterized by an erythematous rash and strawberry tongue. The other types of acute bacterial pharyngitis (e.g., gonococcal, diphtherial, and yersinial) often present as exudative pharyngitis with or without other clinical features. Their etiologies are often suggested only by the clinical history.
The primary goal of diagnostic testing is to separate acute streptococcal pharyngitis from pharyngitis of other etiologies (particularly viral) so that antibiotics can be prescribed more efficiently for patients to whom they may be beneficial. The most appropriate standard for the diagnosis of streptococcal pharyngitis, however, has not been definitively established. Throat swab culture is generally regarded as such. However, this method cannot distinguish between infection and colonization, and it takes 24–48 h to yield results that vary according to technique and culture conditions. Rapid antigen-detection tests offer good specificity (>90%) but lower sensitivity when implemented in routine practice. The sensitivity has also been shown to vary across the clinical spectrum of disease (65–90%). Several clinical prediction systems (Table 31-3) can increase the sensitivity of rapid antigen-detection tests to >90% in controlled settings. Since the sensitivities achieved in routine clinical practice are often lower, several medical and professional societies continue to recommend that all negative rapid antigen-detection tests in children be confirmed by a throat culture to limit transmission and complications of illness caused by group A streptococci. The Centers for Disease Control and Prevention, the Infectious Diseases Society of America, the American College of Physicians, and the American Academy of Family Physicians do not recommend backup culture when adults have negative results in a high-sensitivity, rapid antigen-detection test, however, given the lower prevalence and smaller benefit in this age group.
Table 31-3 Guidelines for the Diagnosis and Treatment of Acute Pharyngitis
Age Group Diagnostic Criteria Treatment Recommendationsa
Adults Clinical suspicion of streptococcal pharyngitis (e.g., fever, tonsillar swelling, exudate, enlarged/tender anterior cervical lymph nodes, absence of cough or coryza)b
Penicillin V, 500 mg PO tid, or with: Amoxicillin, 500 mg PO bid, or History of rheumatic fever or Erythromycin, 250 mg PO qid, or Documented household exposure or Benzathine penicillin G, single dose of 1.2 million units IM Positive rapid strep screen Children Clinical suspicion of streptococcal pharyngitis (e.g., tonsillar swelling, exudate, enlarged/tender anterior cervical lymph nodes, absence of coryza) Amoxicillin, 45 mg/kg qd PO in divided doses (bid or tid), or with: Penicillin VK, 50 mg/kg qd PO in divided doses (bid), or History of rheumatic fever or Cephalexin, 50 mg/kg qd PO in divided doses (qid), or Documented household exposure or Benzathine penicillin G, single dose of 25,000 units/kg IM Positive rapid strep screen or Positive throat culture (for patients with negative rapid strep screen)
aUnless otherwise specified, the duration of therapy is generally 10 d, with appropriate follow-up.
bSome organizations support treating adults who have these symptoms and signs without administering a rapid streptococcal antigen test.
Sources: Cooper et al, 2001; Schwartz et al, 1998.
Cultures and rapid diagnostic tests for other causes of acute pharyngitis, such as influenza virus, adenovirus, HSV, EBV, CMV, and M. pneumoniae, are available in some locations and can be used when these infections are suspected. The diagnosis of acute EBV infection depends primarily on the detection of antibodies to the virus with a heterophile agglutination assay (monospot slide test) or enzyme-linked immunosorbent assay. Testing for HIV RNA or antigen (p24) should be performed when acute primary HIV infection is suspected. If other bacterial causes are suspected (particularly N. gonorrhoeae, C. diphtheriae, or Y. enterocolitica), specific cultures should be requested since these organisms may be missed on routine throat swab culture.
Antibiotic treatment of pharyngitis due to S. pyogenes confers numerous benefits, including a decrease in the risk of rheumatic fever. The magnitude of this benefit is fairly small, however, since rheumatic fever is now a rare disease, even among untreated patients. When therapy is started within 48 h of illness onset, however, symptom duration is also decreased. An additional benefit of therapy is the potential to reduce the spread of streptococcal pharyngitis, particularly in areas of overcrowding or close contact. Antibiotic therapy for acute pharyngitis is therefore recommended in cases where S. pyogenes is confirmed as the etiologic agent by rapid antigen-detection test or throat swab culture. Otherwise, antibiotics should be given in routine cases only when another bacterial cause has been identified. Effective therapy for streptococcal pharyngitis consists of either a single dose of IM benzathine penicillin or a full 10-day course of oral penicillin (Table 31-3). Erythromycin can be used in place of penicillin, although resistance to erythromycin among S. pyogenes strains in some parts of the world (particularly Europe) can prohibit the use of this drug. Newer (and more expensive) antibiotics are also active against streptococci but offer no greater efficacy than the above agents. Testing for cure is unnecessary and may reveal only chronic colonization. There is no evidence to support antibiotic treatment of group C or G streptococcal pharyngitis or of pharyngitis in which Mycoplasma or Chlamydophila has been recovered. Penicillin prophylaxis (benzathine penicillin G, 1.2 million units IM every 3–4 weeks) is indicated for patients at risk of recurrent rheumatic fever.
Treatment of viral pharyngitis is entirely symptom-based except in infection with influenza virus or HSV. For influenza, a number of therapeutic agents exist, including amantadine, rimantadine, and the two newer agents oseltamivir and zanamivir. All of these agents need to be started within 36–48 h of symptom onset to reduce illness duration meaningfully. Of these agents, only oseltamivir and zanamivir are active against both influenza A and influenza B and therefore can be used when local infection patterns are unknown. Oropharyngeal HSV infection sometimes responds to treatment with antiviral agents such as acyclovir, although these drugs are often reserved for immunosuppressed patients.
Although rheumatic fever is the best-known complication of acute streptococcal pharyngitis, the risk of its following acute infection remains quite low. Other complications include acute glomerulonephritis and numerous suppurative conditions, such as peritonsillar abscess (quinsy), otitis media, mastoiditis, sinusitis, bacteremia, and pneumonia—all of which occur at low rates. Although antibiotic treatment of acute streptococcal pharyngitis can prevent the development of rheumatic fever, there is no evidence that it can prevent acute glomerulonephritis. Some evidence supports antibiotic use to prevent the suppurative complications of streptococcal pharyngitis, particularly peritonsillar abscess, which can also involve oral anaerobes such as Fusobacterium. Abscesses are usually accompanied by severe pharyngeal pain, dysphagia, fever, and dehydration; in addition, medial displacement of the tonsil and lateral displacement of the uvula are often evident on examination. Although early use of IV antibiotics (e.g., clindamycin; penicillin G with metronidazole) may obviate the need for surgical drainage in some cases, treatment typically involves needle aspiration or incision and drainage.
Aside from periodontal disease such as gingivitis, infections of the oral cavity most commonly involve HSV or Candida species. In addition to causing painful cold sores on the lips, HSV can infect the tongue and buccal mucosa, causing the formation of irritating vesicles. Although topical antiviral agents (e.g., acyclovir and penciclovir) can be used externally for cold sores, oral or IV acyclovir is often needed for primary infections, extensive oral infections, and infections in immunocompromised patients. Oropharyngeal candidiasis (thrush) is caused by a variety of Candida species, most often C. albicans. Thrush occurs predominantly in neonates, immunocompromised patients (especially those with AIDS), and recipients of prolonged antibiotic or glucocorticoid therapy. In addition to sore throat, patients often report a burning tongue, and physical examination reveals friable white or gray plaques on the gingiva, tongue, and oral mucosa. Treatment, which usually consists of an oral antifungal suspension (nystatin or clotrimazole) or oral fluconazole, is frequently successful. In the uncommon cases of fluconazole-refractory thrush that are seen in some patients with AIDS, other therapeutic options include oral formulations of itraconazole, amphotericin B, or voriconazole as well as the IV echinocandins (caspofungin, micafungin, and anidulafungin).
Vincent's angina, also known as acute necrotizing ulcerative gingivitis or trench mouth, is a unique and dramatic form of gingivitis characterized by painful, inflamed gingiva with ulcerations of the interdental papillae that bleed easily. Since oral anaerobes are the cause, patients typically have halitosis and frequently present with fever, malaise, and lymphadenopathy. Treatment consists of debridement and oral administration of penicillin plus metronidazole, with clindamycin alone as an alternative.
Ludwig's angina is a rapidly progressive, potentially fulminant cellulitis that involves the sublingual and submandibular spaces and that typically originates from an infected or recently extracted tooth, most commonly the lower second and third molars. Improved dental care has substantially reduced the incidence of this disorder. Infection in these areas leads to dysphagia, odynophagia, and "woody" edema in the sublingual region, forcing the tongue up and back with the potential for airway obstruction. Fever, dysarthria, and drooling may also be noted, and patients may speak in a "hot potato" voice. Intubation or tracheostomy may be necessary to secure the airway, as asphyxiation is the most common cause of death. Patients should be monitored closely and treated promptly with IV antibiotics directed against streptococci and oral anaerobes. Recommended agents include ampicillin/sulbactam and high-dose penicillin plus metronidazole.
Postanginal septicemia (Lemierre's disease) is a rare anaerobic oropharyngeal infection caused predominantly by Fusobacterium necrophorum. The illness typically starts as a sore throat (most commonly in adolescents and young adults), which may present as exudative tonsillitis or peritonsillar abscess. Infection of the deep pharyngeal tissue allows organisms to drain into the lateral pharyngeal space, which contains the carotid artery and internal jugular vein. Septic thrombophlebitis of the internal jugular vein can result, with associated pain, dysphagia, and neck swelling and stiffness. Sepsis usually occurs 3–10 days after the onset of sore throat and is often coupled with metastatic infection to the lung and other distant sites. Occasionally, the infection can extend along the carotid sheath and into the posterior mediastinum, resulting in mediastinitis, or it can erode into the carotid artery, with the early sign of repeated small bleeds into the mouth. The mortality rate from these invasive infections can be as high as 50%. Treatment consists of IV antibiotics (penicillin G or clindamycin) and surgical drainage of any purulent collections. The concomitant use of anticoagulants to prevent embolization remains controversial but is often advised.
Infections of the Larynx and Epiglottis
Laryngitis is defined as any inflammatory process involving the larynx and can be caused by a variety of infectious and noninfectious processes. The vast majority of laryngitis cases seen in clinical practice in developed countries are acute. Acute laryngitis is a common syndrome caused predominantly by the same viruses responsible for many other URIs. In fact, most cases of acute laryngitis occur in the setting of a viral URI.
Nearly all major respiratory viruses have been implicated in acute viral laryngitis, including rhinovirus, influenza virus, parainfluenza virus, adenovirus, coxsackievirus, coronavirus, and RSV. Acute laryngitis can also be associated with acute bacterial respiratory infections, such as those caused by group A Streptococcus or C. diphtheriae (although diphtheria has been all but eliminated in the United States). Another bacterial pathogen thought to play a role (albeit unclear) in the pathogenesis of acute laryngitis is M. catarrhalis, which has been recovered on nasopharyngeal culture from a significant percentage of people with acute laryngitis. Chronic laryngitis of infectious etiology is much less common in developed than in developing countries. Laryngitis due to Mycobacterium tuberculosis is often difficult to distinguish from laryngeal cancer, in part because of the frequent absence of signs, symptoms, and radiographic findings typical of pulmonary disease. Histoplasma and Blastomyces may cause laryngitis, often as a complication of systemic infection. Candida species can cause laryngitis as well, often in association with thrush or esophagitis and particularly in immunosuppressed patients. Rare cases of chronic laryngitis are due to Coccidioides and Cryptococcus.
Laryngitis is characterized by hoarseness and can also be associated with reduced vocal pitch or aphonia. As acute laryngitis is caused predominantly by respiratory viruses, these symptoms usually occur in association with other symptoms and signs of URI, including rhinorrhea, nasal congestion, cough, and sore throat. Direct laryngoscopy often reveals diffuse laryngeal erythema and edema, along with vascular engorgement of the vocal folds. In addition, chronic disease (e.g., tuberculous laryngitis) often includes mucosal nodules and ulcerations visible on laryngoscopy; these lesions are sometimes mistaken for laryngeal cancer.
Acute laryngitis is usually treated with humidification and voice rest alone. Antibiotics are not recommended except when group A Streptococcus is cultured, in which case penicillin is the drug of choice. The choice of therapy for chronic laryngitis depends on the pathogen, whose identification usually requires biopsy with culture. Patients with laryngeal tuberculosis are highly contagious because of the large number of organisms that are easily aerosolized. These patients should be managed in the same way as patients with active pulmonary disease.
The term croup actually denotes a group of diseases collectively referred to as "croup syndrome," all of which are acute and predominantly viral respiratory illnesses characterized by marked swelling of the subglottic region of the larynx. Croup primarily affects children <6 years old. For a detailed discussion of this entity, the reader is referred to a text of pediatric medicine.
Acute epiglottitis (supraglottitis) is an acute, rapidly progressive cellulitis of the epiglottis and adjacent structures that can result in complete—and potentially fatal—airway obstruction in both children and adults. Before the widespread use of H. influenzae type b (Hib) vaccine, this entity was much more common among children, with a peak incidence at ~3.5 years of age. In some countries, mass vaccination against Hib has reduced the annual incidence of acute epiglottitis in children by >90%; in contrast, the annual incidence in adults has changed little since the introduction of Hib vaccine. Because of the danger of airway obstruction, acute epiglottitis constitutes a medical emergency, particularly in children, and prompt diagnosis and airway protection are of utmost importance.
After the introduction of the Hib vaccine in the mid-1980s, disease incidence among children in the United States declined dramatically. Nevertheless, lack of vaccination or vaccine failure has meant that many pediatric cases seen today are still due to Hib. In adults and (more recently) in children, a variety of other bacterial pathogens have been associated with epiglottitis, the most common being group A Streptococcus. Other pathogens seen less frequently include S. pneumoniae, Haemophilus parainfluenzae, and S. aureus. Viruses have not yet been established as causes of acute epiglottitis.
Clinical Manifestations and Diagnosis
Epiglottitis typically presents more acutely in young children than in adolescents or adults. On presentation, most children have had symptoms for <24 h, including high fever, severe sore throat, tachycardia, systemic toxicity, and (in many cases) drooling while sitting forward. Symptoms and signs of respiratory obstruction may also be present and may progress rapidly. The somewhat milder illness in adolescents and adults often follows 1–2 days of severe sore throat and is commonly accompanied by dyspnea, drooling, and stridor. Physical examination of patients with acute epiglottitis may reveal moderate or severe respiratory distress, with inspiratory stridor and retractions of the chest wall. These findings diminish as the disease progresses and the patient tires. Conversely, oropharyngeal examination reveals injection that is much less severe than would be predicted from the symptoms—a finding that should alert the clinician to a cause of symptoms and obstruction that lies beyond the tonsils. The diagnosis is often made on clinical grounds, although direct fiberoptic laryngoscopy is frequently performed in a controlled environment (e.g., an operating room) in order to visualize and culture the typical edematous "cherry-red" epiglottis and to facilitate placement of an endotracheal tube. Direct visualization in an examination room (e.g., with a tongue blade and indirect laryngoscopy) is not recommended because of the risk of immediate laryngospasm and complete airway obstruction. Lateral neck radiographs and laboratory tests can assist in the diagnosis but may delay the critical securing of the airway and cause the patient to be moved or repositioned more than is necessary, thereby increasing the risk of further airway compromise. Neck radiographs typically reveal an enlarged edematous epiglottis (the "thumbprint sign," Fig. 31-2), usually with a dilated hypopharynx and normal subglottic structures. Laboratory tests characteristically document mild to moderate leukocytosis with a predominance of neutrophils. Blood cultures are positive in a significant proportion of cases.
Acute epiglottitis. In this lateral soft tissue radiograph of the neck, the arrow indicates the enlarged edematous epiglottis (the "thumbprint sign").
Security of the airway is always of primary concern in acute epiglottitis, even if the diagnosis is only suspected. Mere observation for signs of impending airway obstruction is not routinely recommended, particularly in children. Many adults have been managed with observation only since the illness is perceived to be milder in this age group, but some data suggest that this approach may be risky and probably should be reserved only for adult patients who have yet to develop dyspnea or stridor. Once the airway has been secured and specimens of blood and epiglottis tissue have been obtained for culture, treatment with IV antibiotics should be given to cover the most likely organisms, particularly H. influenzae. Because rates of ampicillin resistance in this organism have risen significantly in recent years, therapy with a β-lactam/β-lactamase inhibitor combination or a second- or third-generation cephalosporin is recommended. Typically, ampicillin/sulbactam, cefuroxime, cefotaxime, or ceftriaxone is given, with clindamycin and TMP-SMX reserved for patients allergic to β-lactams. Antibiotic therapy should be continued for 7–10 days and should be tailored, if necessary, to the organism recovered in culture. If the household contacts of a patient with H. influenzae epiglottitis include an unvaccinated child under the age of 4, all members of the household (including the patient) should receive prophylactic rifampin for 4 days to eradicate carriage of H. influenzae.
Infections of the Deep Neck Structures
Deep neck infections are usually extensions of infection from other primary sites, most often within the pharynx or oral cavity. Many of these infections are life-threatening but are difficult to detect at early stages when they may be more easily managed. Three of the most clinically relevant spaces in the neck are the submandibular (and sublingual) space, the lateral pharyngeal (or parapharyngeal) space, and the retropharyngeal space. These spaces communicate with one another and with other important structures in the head, neck, and thorax, providing pathogens with easy access to areas including the mediastinum, carotid sheath, skull base, and meninges. Once infection reaches these sensitive areas, mortality rates can be as high as 20–50%.
Infection of the submandibular and/or sublingual space typically originates from an infected or recently extracted lower tooth. The result is the severe, life-threatening infection referred to as Ludwig's angina (see "Oral Infections," above). Infection of the lateral pharyngeal (or parapharyngeal) space is most often a complication of common infections of the oral cavity and upper respiratory tract, including tonsillitis, peritonsillar abscess, pharyngitis, mastoiditis, or periodontal infection. This space, located deep to the lateral wall of the pharynx, contains a number of sensitive structures, including the carotid artery, internal jugular vein, cervical sympathetic chain, and portions of cranial nerves IX through XII; at its distal end, it opens into the posterior mediastinum. Involvement of this space with infection can therefore be rapidly fatal. Examination may reveal some tonsillar displacement, trismus, and neck rigidity, but swelling of the lateral pharyngeal wall can easily be missed. The diagnosis can be confirmed by CT. Treatment consists of airway management, operative drainage of fluid collections, and at least 10 days of IV therapy with an antibiotic active against streptococci and oral anaerobes (e.g., ampicillin/sulbactam). A particularly severe form of this infection involving the components of the carotid sheath (postanginal septicemia, Lemierre's disease) is described above (see "Oral Infections,"). Infection of the retropharyngeal space can also be extremely dangerous, as this space runs posterior to the pharynx from the skull base to the superior mediastinum. Infections in this space are more common among children <5 years old because of the presence of several small retropharyngeal lymph nodes that typically atrophy by the age of 4 years. Infection is usually a consequence of extension from another site of infection, most commonly acute pharyngitis. Other sources include otitis media, tonsillitis, dental infections, Ludwig's angina, and anterior extension of vertebral osteomyelitis. Retropharyngeal space infection can also follow penetrating trauma to the posterior pharynx (e.g., from an endoscopic procedure). Infections are commonly polymicrobial, involving a mixture of aerobes and anaerobes; group A β-hemolytic streptococci and S. aureus are the most common pathogens. M. tuberculosis was a frequent cause in the past but now is rarely involved in the United States.
Patients with retropharyngeal abscess typically present with sore throat, fever, dysphagia, and neck pain and are often drooling because of difficulty and pain with swallowing. Examination may reveal tender cervical adenopathy, neck swelling, and diffuse erythema and edema of the posterior pharynx as well as a bulge in the posterior pharyngeal wall that may not be obvious on routine inspection. A soft tissue mass is usually demonstrable by lateral neck radiography or CT. Because of the risk of airway obstruction, treatment begins with securing of the airway, which is followed by a combination of surgical drainage and IV antibiotic administration. Initial empirical therapy should cover streptococci, oral anaerobes, and S. aureus; ampicillin/sulbactam, clindamycin alone, or clindamycin plus ceftriaxone is usually effective. Complications result primarily from extension to other areas; for example, rupture into the posterior pharynx may lead to aspiration pneumonia and empyema. Extension may also occur to the lateral pharyngeal space and mediastinum, resulting in mediastinitis and pericarditis, or into nearby major blood vessels. All these events are associated with a high mortality rate.
American Academy of Pediatrics Subcommittee on Management of Acute Otitis Media: Diagnosis and management of acute otitis media. Pediatrics 113:1451, 2004 American Academy of Pediatrics Subcommittee on Management of Sinusitis and Committee on Quality Improvement: Clinical practice guideline: Management of sinusitis. Pediatrics 108:798, 2001 Cooper RJ et al: Principles of appropriate antibiotic use for acute pharyngitis in adults: Background. Ann Intern Med 134:509, 2001 [PMID: 11255530] Dowell SF et al: Otitis media—principles of judicious use of antimicrobial agents. Pediatrics 101:165, 1998 Gonzales R et al: Principles of appropriate antibiotic use for treatment of nonspecific upper respiratory tract infections in adults: Background. Ann Intern Med 134:490, 2001 [PMID: 11255526] Hickner JM et al: Principles of appropriate antibiotic use for acute rhinosinusitis in adults: Background. Ann Intern Med 134:498, 2001 [PMID: 11255528] Piccirillo JF: Acute bacterial sinusitis. N Engl J Med 351:902, 2004 [PMID: 15329428] Rafei K et al: Airway infectious disease emergencies. Pediatr Clin North Am 53:215, 2006 [PMID: 16574523] Schwartz B et al: Pharyngitis—principles of judicious use of antimicrobial agents. Pediatrics 101:171, 1998 Sinus and Allergy Health Partnership: Antimicrobial treatment guidelines for acute bacterial rhinosinusitis. Otolaryngol Head Neck Surg 130:1, 2004 Van Zuijlen DA et al: National differences in incidence of acute mastoiditis: Relationship to prescribing patterns of antibiotics for acute otitis media? Pediatr Infect Dis J 20:140, 2001 Wenzel RP et al: Acute bronchitis. N Engl J Med 355:2125, 2006 [PMID: 17108344]