Necrotizing Otitis Externa

Malignant or necrotizing otitis externa (MOE) is an aggressive infection that begins as otitis externa but spreads through surrounding tissues toward the skull base. It is seen predominantly in the elderly, diabetic, or immunocompromised patient. P. aeruginosa is the most common causative pathogen; however, staphylococcal species are also known to cause the infection (11). Fungal causes of MOE are less common, with Aspergillus species the predominating pathogen (12).

MOE initially presents with symptoms and signs of AOE. Subsequently, it may progress to temporal bone osteomyelitis and affect adjacent cranial nerves (VII to XII), blood vessels, and soft tissue. If not treated aggressively, the infection can expand intracranially leading to neurologic symptoms. On otoscopic examination, granulation tissue is classically seen at the bony–cartilaginous junction (11–13). A raised erythrocyte sedimentation rate and abnormal computed tomography (CT) or magnetic resonance imaging (MRI) scan help to confirm the clinical diagnosis. Other imaging techniques that assist in diagnosis include gallium scan, indium-labeled leukocyte scan, technetium bone scan, and single-photon emission tomographs (12,14). Patients will require treatment with systemic antibiotics that cover pseudomonal and staphylococcal infection, including methicillin-resistant Staphylococcus aureus (11,12).

Furunculosis (Ear Canal Abscess)

Furunculosis is a localized infection of the ear canal that is usually caused by an infected hair follicle. It may present with otalgia, otorrhea, and localized tenderness. A tender, often fluctuant nodule within the lateral ear canal can be identified on the examination. The most common pathogen is S. aureus. The treatment includes application of heat, incision and drainage of the infected area, and systemic antibiotic treatment with staphylococcal coverage (15).

Acute Otitis Media

Acute otitis media is an inflammation of the middle ear, which is generally characterized by the rapid onset of otalgia, aural fullness, and occasionally fever. In the pediatric patient, more common signs are irritability, sleeplessness, and pulling at the affected ear. On pneumatic otoscopy, the tympanic membrane will have a red, opaque, and bulging appearance with decreased mobility due to the accumulation of purulent fluid in the middle ear space. Additionally, the tympanic membrane may rupture, so that patients will present with otorrhea (16,17).

Predominant pathogens in AOM are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis (18). Observation for 24 to 48 hours in the case of a nonsevere illness in an otherwise healthy individual greater than 6 months of age is an initial option, with 60% resolving within 24 hours without antibiotic treatment. If symptoms persist, antimicrobial therapy should be initiated. Amoxicillin is recommended for initial treatment of acute otitis media, at a recommended dose of 80 to 90 mg/kg/d. In the case of penicillin allergy, azithromycin, clarithromycin, erythromycin–sulfisoxazole, or trimethoprim–sulfamethoxazole could be used. Due to the increased incidence of β-lactamase–producing organisms, the bacterial coverage should be expanded if there is no improvement within 48 to 72 hours. In very rare cases, if pain or fever is excessive, immediate tympanocentesis or myringotomy may be required, taking care to send purulent fluid for culture in this case (18,19).

Otitis media with effusion is the presence of fluid in the middle ear without signs or symptoms of acute ear infection and should be distinguished from acute otitis media. Otitis media with effusion often occurs as a result of eustachian tube dysfunction, or middle ear inflammation following acute infection. It is most common in the pediatric population between the ages of 6 months and 4 years, although it may occur at any age. On pneumatic otoscopy, the tympanic membrane is often retracted, will have decreased mobility, and an air–fluid level or bubbles are often visualized. Patients often report a decrease in hearing. Otitis media with effusion is often self-limited and is likely to resolve spontaneously within 3 months. If it persists, hearing testing is recommended, particularly in children with language delay, learning problems, or suspicion of significant hearing loss (17,20). In individuals with hearing loss and persistent middle ear effusion for greater than 3 months, myringotomy with tympanostomy tube insertion should be considered (21). Medical treatment, such as decongestants, has not been shown to be effective in the treatment of middle ear effusion. In an adult presenting with a unilateral middle ear effusion, an examination of the nasopharynx should be performed to rule out the possibility of a nasopharyngeal mass causing obstruction of the eustachian tube.

Chronic Otitis Media

Chronic otitis media is diagnosed when infection persists for more than 1 to 3 months. It may present as chronic suppurative otitis media (CSOM), which is characterized by persistent bacterial infection and drainage from the ear, or as chronic otitis media with effusion (COME), which results from unresolving inflammation of the middle ear and persistent middle ear secretions with an intact tympanic membrane. Chronic otitis media may be associated with cholesteatoma, which is a keratin cyst that forms from an accumulation of squamous debris in the middle ear with potential for growth and erosion of surrounding structures (22).

Patients with CSOM will present with hearing loss, painless purulent otorrhea, and a chronic tympanic membrane perforation. Evaluation includes visual examination, bacterial culture, and radiographic imaging. Gram-negative and anaerobic organisms are usually seen on cultures, with P. aeruginosa being a predominant organism. Temporal bone CT scan allows evaluation of the extent of disease and reveals potential complications. Medical treatment of CSOM consists of topical debridement, along with topical and systemic antibiotics. Topical drops often consist of antibiotic and steroid combinations (23). Ciprofloxacin is recommended for systemic use; however, it cannot be given to children under 17 years of age. Surgical treatment is performed for eradication of the infection and reconstruction of the middle ear (22).

COME is characterized by persistent hearing loss and a middle ear space filled with thick mucus. Chronic inflammation of the middle ear often begins with obstruction of the eustachian tube. The resulting negative pressure in the middle ear leads to collection of transudate. Secondary to chronic inflammation, the middle ear lining becomes hyperplastic and produces further mucous. On examination, the tympanic membrane is intact and has a thickened, opaque appearance. On pneumatic otoscopy, the tympanic membrane does not move. As the disease progresses the tympanic membrane starts to retract and drape over the ossicles. Nasal obstruction and sinus disease may contribute to Eustachian tube insufficiency and lead to middle ear fluid accumulation. Treatment of COME consists of fluid drainage, which is accomplished by myringotomy with ventilation tube insertion. Treating sinus disease and relieving nasal obstruction may improve eustachian tube function (20).

Acute or chronic forms of otitis media, if left untreated, may lead to extracranial or intracranial complications (Table 87.1). Hearing loss, tympanic membrane perforation, atelectasis of the middle ear, mastoiditis, apical petrositis, facial nerve paralysis, labyrinthitis, and ossicular discontinuity are some of the possible intratemporal sequelae of otitis media. Meningitis, extradural abscess, subdural empyema, encephalitis, brain abscess, sigmoid sinus thrombosis, and hydrocephalus are potential intracranial complications. Intracranial complications should be suspected in individuals presenting with changes in mental status (17,24,25).

TABLE 87.1 Complications of Otitis Media

Labyrinthitis

Labyrinthitis is an inflammation or infection of the vestibular apparatus. Patients typically present with vertigo, nausea, vomiting, and malaise. The etiology is most often viral or traumatic, but can be bacterial. Bacterial labyrinthitis most often arises as a spread of infection from meningitis or otitis media. It can be serous or suppurative. Viral infections such as mumps, measles, Lassa fever, varicella-zoster, syphilis, and herpes simplex have been associated with labyrinthitis. Labyrinthitis may or may not be associated with a sensorineural hearing loss, which can be temporary or permanent depending on the etiology, patient’s age, and severity of the loss (26).

Idiopathic Facial Paralysis (Bell Palsy)

Idiopathic facial paralysis is an acute unilateral peripheral facial nerve weakness. It is a diagnosis of exclusion, and only made when other causes of paralysis, such as systemic diseases, infection, trauma, central nervous system disorders, and neoplasm, are ruled out. Patients will usually present with abrupt onset of unilateral facial weakness. Other symptoms may include numbness or pain around the ear, decreased taste, and increased sensitivity to sounds (27). Herpes simplex virus is thought to be an etiologic factor for this disease (28). Bell palsy most commonly occurs in individuals between 10 and 40 years of age. Pregnant women and individuals with diabetes mellitus are at a higher risk of developing Bell palsy. Most cases spontaneously improve within 6 months. Residual facial nerve weakness may persist in about 15% of affected individuals (27). In patients older than 16 years of age, the recommended treatment consists of the early administration (first 72 hours) of high-dose prednisone. Antivirals may be added, but have not shown to have benefit apart from steroids (29). Patients should be educated about using artificial tears and protecting the eye during sleep to prevent corneal abrasion and eye infection.

Ramsay Hunt Syndrome

Ramsay Hunt syndrome is caused by reactivation of varicella-zoster virus (VZV) in the geniculate ganglion and is associated with eruption of an auricular or oropharyngeal vesicular rash, facial paralysis, and otalgia (30). In addition, tinnitus, hearing loss, nausea, vomiting, vertigo, and nystagmus can be the accompanying symptoms (31). Patients with Ramsay Hunt syndrome present more severe symptoms and have a worse prognosis for recovery of facial nerve function relative to patients with Bell palsy. The timing between onset of facial paralysis and vesicular eruption may vary. Some patients present with facial paralysis, have a rise in VZV antibody, but never develop cutaneous manifestations. Initiation of early treatment with prednisone and acyclovir is currently recommended (32).

Chondritis/Perichondritis

Chondritis/perichondritis of the ear is an infection of auricular cartilage/perichondrium. It is often caused by penetrating injury to the ear, particularly piercing of the pinna (33). Blunt trauma with auricular hematoma can also lead to infection. Cartilage involvement can also be seen in spreading otitis externa. Because of its relative avascularity, cartilage is more susceptible to infection. Infections are more often reported during warm weather, after exposure to water in pools, lakes, or hot tubs. Patients present with a very tender, erythematous, and indurated auricle. It is generally doughy on palpation and is rarely fluctuant. P. aeruginosa has been identified as the most likely cause of the infection, but S. aureus must also be considered (33,34). Treatment consists of removing any foreign body, and drainage of any abscess or hematoma. Patients should be treated aggressively with antibiotics that provide coverage for Pseudomonas. Cartilage necrosis or subperichondrial fibrosis leading to auricular deformity may be seen following the infectious process. Recurrent auricular chondritis should raise suspicion for the diagnosis of relapsing polychondritis (35).

NASAL INFECTIONS

Rhinosinusitis

Acute Bacterial Rhinosinusitis

Acute bacterial rhinosinusitis most often develops following a viral upper respiratory infection, and is distinguished by a duration of greater than 10 days (38). Some of the presenting diagnostic symptoms include purulent nasal discharge, nasal congestion, maxillary, tooth or facial pain, and worsening of symptoms following initial improvement, but are not specific for bacterial sinusitis as opposed to viral causes. Predisposing physiologic factors include obstruction of sinus ostia, reduction in number or function of sinus cilia, and a change in the quality of secretions (39). The most common pathogens are S. pneumoniae, H. influenzae, M. catarrhalis, and S. aureus. In immunocompromised patients, in patients with cystic fibrosis, and in patients with sinusitis of nosocomial origin (on mechanical ventilation, with nasal tubing), P. aeruginosa and other aerobic gram-negative rods are common causative pathogens (40). Anaerobic bacteria are usually associated with sinusitis of dental origin (41). It is often difficult to distinguish between viral and bacterial sinusitis. The diagnosis is usually based on medical history and clinical findings. With bacterial sinusitis, symptoms are usually present for more than 10 days. Sinus puncture with aspiration of sinus contents is the most accurate diagnostic technique; however, since it is invasive it is not commonly used. Radiographic imaging may help confirm the presence of sinus disease. Plain films can be difficult to interpret and should not be ordered. CT findings will include thickened mucosa, sinus opacification, or air–fluid levels, and is the preferred examination although these findings are nonspecific (Fig. 87.2). CT scans are rarely ordered to confirm acute infection unless there is concern about possible complications, such as in the case of frontal or sphenoid sinus infection. Nasal endoscopy will often demonstrate swelling within the middle meatus or sphenoethmoidal recess, with purulent discharge. Antimicrobial treatment of acute sinusitis includes amoxicillin (first line), amoxicillin–clavulanic acid, cephalosporins, trimethoprim–sulfamethoxazole, macrolides, doxycycline, and quinolones (42). Treatment can be supplemented with nasal saline irrigation, antihistamines, decongestants, and intranasal steroids (43). If there is minimal improvement after 2 to 3 days, a change in antibiotics may be indicated. Frontal sinus disease in particular may require early surgical management. If not treated, acute bacterial sinusitis may be complicated by the development of a number of orbital and intracranial complications, particularly when the infection involves the ethmoid, frontal, or sphenoid sinuses, and may require additional surgery to treat the complications (Table 87.2) (44–46).

Chronic Bacterial Rhinosinusitis

Chronic bacterial rhinosinusitis is diagnosed when the symptoms of sinusitis are present for at least 12 weeks. Symptoms include nasal congestion, purulent discharge, facial pressure, and anosmia. Nasal endoscopy may reveal nasal polyps, edema, or purulent discharge. CT findings may reveal mucosal thickening, sinus opacification, polyps, or air–fluid levels (47,48). Predisposing factors include smoking, inhalant allergies, obstruction of the ostiomeatal complex (Fig. 87.3), immune deficiency, and genetic factors (48). Pathogens are similar to those found in acute infections, with a greater predominance of Staphylococcus, Pseudomonas, and possibly anaerobes. The most common anaerobic bacteria include Peptostreptococcus species, Fusobacterium species, Prevotella, and Porphyromonas species. In cases of P. aeruginosa, aminoglycosides, fourth-generation cephalosporins, or fluoroquinolones are used in treatment (40). In chronic bacterial rhinosinusitis (CRS), a prolonged course of antibiotic therapy is often required, ranging from 3 to 6 weeks, with any imaging occurring after the completion of medical therapy. Adjunctive therapy including decongestants, mucolytics, and steroids (both intranasal and oral) may be helpful. In patients with continued symptoms, recent guidelines recommend allergy testing to exclude allergic rhinitis as a contributing factor, as well as considering other immunologic disorders. Testing for cystic fibrosis in younger patients may also be helpful (43,49). If patients do not respond to medical therapy, functional endoscopic sinus surgery may be indicated (50).

TABLE 87.2 Potential Complications of Sinusitis

Viral Rhinosinusitis

Viral rhinosinusitis is more common than bacterial. The most common pathogens are rhinovirus, influenza viruses, adenoviruses, parainfluenza viruses, and respiratory syncytial virus (RSV). Inflammatory symptoms of viral rhinosinusitis are thought to be due to the host response to the virus. Patients may present with symptoms of the common cold such as nasal congestion, nasal discharge, sneezing, cough, fever, malaise, and muscle ache. Viral rhinosinusitis is usually self-limited. Antiviral therapy may be used for specific viruses. Nasal saline irrigation and various anti-inflammatory medications may aid with symptomatic relief (51).

Fungal Rhinosinusitis

Acute Necrotizing Fungal Rhinosinusitis. Acute invasive necrotizing fungal rhinosinusitis is a fulminant invasive fungal infection that is often life-threatening. It usually affects immunocompromised patients, such as diabetics, patients with immunodeficiency disorders, and patients undergoing chemotherapy. Patients often present with acute onset of fever, headache, cough, mucosal ulcerations, and epistaxis. On examination, necrotic black turbinates and nasal eschar spreading through mucosa, soft tissue, and bone are seen. Histopathologic evaluation of involved tissue reveals necrosis and inflammatory infiltrate with giant cells, lymphocytes, and neutrophils. Gomori methenamine silver or periodic acid-Schiff histologic fungal stains demonstrate tissue and vascular invasion by fungal hyphae. Most common pathogens are Aspergillus, Rhizopus, and Mucor species. Treatment involves emergent surgical debridement, intravenous antifungal drugs such as Amphotericin B, and treatment of the underlying immunocompromising disorder. If disease is not treated, it may lead to rapid dissemination and death (52,53).

Chronic Invasive Fungal Rhinosinusitis. Chronic invasive fungal rhinosinusitis is a chronic (greater than 3 months) and slowly invasive fungal infection. It too usually affects immunocompromised patients, particularly diabetics and patients requiring prolonged corticosteroid treatment, but has also been reported in otherwise healthy individuals. Patients may present with orbital apex syndrome due to the extension of the infection into the orbit. This will result in decreased vision, ocular immobility, and proptosis. Erosion may also occur into the infratemporal fossa, the anterior cranial fossa, or the premaxillary region. Histopathology reveals a dense accumulation of hyphae, with a chronic inflammatory infiltrate of lymphocytes, giant cells, and necrotizing granulomas. If left untreated, the disease may invade cerebral blood vessels leading to ischemic injury, or directly invade the brain. Treatment involves repeated surgical debridement and antifungal drugs (52).

Mycetoma

Mycetoma, also described as a fungal ball, is an accumulation of degenerating fungal hyphae within a sinus cavity, most often involving the maxillary sinus. Patients are generally immunocompetent and will present with symptoms of nasal obstruction, postnasal drainage, and localized facial pain. Risk factors include previous sinus surgery, oral–sinus fistula, and chemotherapy treatment. The presence of chronic mucosal inflammation may be noted on nasal endoscopy, along with green–black concretions within the middle meatus. A CT study will reveal sinus opacification, often with areas of calcification. MRI may be definitive, demonstrating isodense opacification on T1 images, with a ring of enhancement and central attenuation on T2 (Fig. 87.4). This result is from ferromagnetic deposits related to the fungal infection. Aspergillus is the most common organism, although fungal cultures are often found to be negative. Treatment involves surgical removal of the fungal ball with adequate drainage of the affected sinus (52,55).

Allergic Fungal Sinusitis

The etiology of allergic fungal sinusitis (AFS) is thought to be in part an allergic response to the presence of noninvasive fungi in the sinus cavity, and has been likened to allergic bronchopulmonary aspergillosis (54,56). Patients will commonly present with hypertrophic sinus disease and nasal polyps. Symptoms of headache, paranasal fullness, and nasal discharge are often reported. Sinus CT often reveals the presence of chronic sinusitis with hyperattenuation present in the opacified sinus, creating an inhomogeneous appearance often with areas of calcification (Fig. 87.5). Serum IgE levels are often elevated, and histologic evaluation reveals the presence of allergic mucin, containing fungal hyphae and elevated eosinophils; there is no evidence of mucosal invasion. Intraorbital and intracranial expansion may occur secondary to pressure resorption of surrounding bone. The most common causative agents are Bipolaris spicifera and Curvularia lunata. Other causative agents are Exserohilum rostratum, Alternatia species, and Aspergillus species. Treatment consists of sinus surgery to remove the diseased mucosa and allergic mucin, although recurrence is common. Once AFS is diagnosed, if there are no contraindications, treatment with corticosteroids should be initiated. Other treatments include surgical debridement, immunotherapy, antibiotics, and nonsteroidal immunomodulatory medications (57).

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