Fungal Ear Infection:

  • Aspergillus species are ubiquitous molds found in soil, on plants, and in decomposing organic materials.
  • The most common species causing aspergillosis are A fumigatus and A flavus.
  • Rare but frequently lethal infection.
  • Risk factors include low CD4 count, neutropenia, corticosteroids, concurrent malignancy with chemotherapy, HIV-related phagocytic impairment, previous respiratory infections, broad-spectrum antibiotic exposure.

Aspergillosis

Clinical Manifestations:

  • Pulmonary aspergillosis is the most common presentation.
  • Invasive pulmonary aspergillosis associated with fever, cough, dyspnea, pleuritic pain.
  • Additional manifestations include necrotizing tracheobronchitis, pseudomembranous. tracheobronchitis, CNS involvement, cutaneous, sinus, middle ear and mastoid infection.

Aspergilosis:

  • Usually isolated from the blood but also readily isolated from lung, sinus, brain, and skin biopsy.
  • Definitive diagnosis includes histopathologic demonstration of organisms in biopsy specimens.
  • Presumptive diagnosis of respiratory tract infection can be made if Aspergillus species is recovered from respiratory sample.

Diagnosis:

  1. Chest radiograph demonstrates either diffuse interstitial pneumonitis or localized wedge-shaped infiltrates.
  2. CT of chest may be used to identify a “halo” sign.
  3. Cavitation and air crescent formation in chest CDT more frequent in older children and adults.

Prevention:

  • Consider excluding plants and flowers from rooms and avoiding food items such as nuts and spices.
  • Erect suitable barriers between patient care and construction sites, clean shower heads routinely as well as hot-water faucets and air-handling systems.

Treatment:

  • Voriconazole is recommended for treatment of invasive aspergillosis.
  • Adult data indicate that voriconazole is superior to amphotericin B but data in children are limited.
  • Recommended dosage for children is 6-8 mg/kg IV (or 8 mg/kg orally) Q12H, followed by 7 mg/kg IV or orally twice daily.
  • Treatment is continued for 12 weeks.

Adverse Effects and Treatment Failure:

  • Voriconazole side effects include reversible dose-dependent visual disturbances, elevated liver enzymes, and occasional skin rash.
  • Amphotericin toxicity is associated primarily with fever, chills, and nephrotoxicity.
  • Efficacy of antifungal therapy for aspergillosis is poor.
  • Experimental approaches include evaluation of caspofungin.

Otitis Externa:

  • Pain and itching that results may be severe because of the limited space for expansion of the inflamed tissues.
  • Otitis externa can be subdivided into 4;
  • Acute localised otitis externa,2.Acute diffuse otitis externa 3.Chronic otitis externa and 4.Malignant otitis externa.
  • Infection of the external auditory canal(otitis externa) is similar to infection of skin and soft tissue elsewhere.
  • Unique problems occur because the canal is narrow and tortuous, fluid and foreign objects enter, are trapped and cause maceration and irritation of superficial tissues.
  • The external auditory canal is about 2.5cm long from the conchae of the auricle to the tympanic membrane.
  • The outer half of the canal is cartilaginous,the medial half tunnels through the temporal bone.
  • A constriction, the isthmus is present at the juntion of the osseus and cartilaginous parts.
  • The skin of the canal is thicker in the cartilaginous portion and includes a well developed dermis and subcutaneous layer.
  • The skin lining the osseus portion is thinner and and lacks a subcutaneous layer.
  • Hair follicles are numerous in the outer third and fewer in the inner 2/3 of the canal.

Aetiological Agents:

  • The microbial flora of the external Canal is similar to the flora of the skin elsewhere.
  • There is predominance of staph. Epidermidis , S. aureus and corynebacteria  and lesser extent anaerobic bacteria like propioni bacterium acnes.
  • Others streptococcus pneumoniae, Haemophilus, influenza, moraxella catarhalis.
  • Gm neg bacilli- Pseudomonas aeruginosa.

Pathogenesis:

  • The ear canal epithelium absorbs moisture from the environment.
  • Desquamation of the superficial layers of the epithelium may follow; In this warm moist environment, the organisms in the canal may flourish and ivade the macerated skin.
  • Inflammation and suppuration follow.

Clinical Manifestations:

  • Acute localised otitis externa may occur as a pustule or furuncle associated with hair follicles.-Staph aureus.
  • Erysipelas caused by group A sreptococcus- may cause hemorrhagic bullae on the canal and tympanic membrane.
  • Adenopathy in the lymphatic drainage areas is often present.

Clinical Manifestations:

  • Acute diffuse otitis externa(swimmers ear) occurs mainly in hot and humid weather.
  • Ear is itchy, painful and canal is edematous and red.
  • Gm neg bacilli esp P aeruginosa.
  • Treatment-topical eg neomycin/polymyxin in steroid/systemic antibiotics
  • Chronic otitis externa- due to irritation of drainage from the middle ear in patients with chronic suppurative otitid media.
  • Itching may be severe. Management is by treating the otitis media also.
  • Organisms rare-mycobacteria, treponemes, yaws, leprosy.
  • Invasive malignant otitis externa is a severe necrotizing infection that spreads from the squamous epithelium of the ear canal to adjacent areas of soft tissue, blood vessels , cartilage and bone.
  • This invasive otitis externa is associated with pain and tenderness of the tissues around the ear and mastoid accompanied by pus drainage from the canal.
  • At risk include diabetics, immunocompromised, debilitated and elderly patients.
  • Complications- life threatening disease may result by spread of infection to the meninges and brain.

Malignant otitis externa cont:

  • Cranial nerves 7, 9,10,12 may be paralysed.
  • Cause – P aeruginosa.
  • Treatment-Clean the canal devitalised tissues removed,ear drops with antipseudomonal and steroid activity given and systemic therapy for 4-6 weeks.ticarcillin/piperacillin/a ceftazidime with aminoglycoside.

Otitis Media:

  • Defined by presence of fluid in the middle ear accompanied by signs and symptoms of the illness.
  • Peak incidence occurs in the first 3 yrs of life.
  • The disease is less common in the school aged child, adolescent and adult.

Associated Factors:

  • Otitis media has been associated with;
  • Immunosuppression, passive smoking, poor breastfeeding, introduction of infants into large day care groups,
  • Race and ethnicity-canadian eskimos and australian aborigines have extraordinary incidence and severeity of otitis media.
  • Age at the time of first episode of acute otitis media is a powerful predictor of recurrent middle ear infections.
  • Males >females.
  • Some children have anatomical changes- cleft palate, cleft uvula, submucous cleft – or alteration of the normal physiologic defenses-patulous eustachian tube.

Pathogenesis:

  • The middle ear is lined by respiratory epithelium with ciliated cells mucus secreting goblet cells and cells capable of secreting local immunoglobulins.
  • Anatomic or physiological dysfuntion of the Eustachian tube appears to play a critical role in the development of otitis media.
  • The eustachian tube has at least 3 physiologic functions  with respect to the middle ear.
  • These are 1. protection of the ear from nasopharyngeal secretions,2. drainage into the nasopharynx of secretions produced from the middle ear, 3.Ventilation of the middle ear to equilibrate pressures to be as the atmospheric –external ear canal pressure.
  • When one or more of these funtions is compromised,accumulation of fluid in the middle ear and subsequent infections may occur.
  • (congestion of the mucosa of the eustachian tube can result in obstruction;secretions that are constantly formed by the mucosa of the middle ear accumulate behind the obstruction, and If a bacterial agent is present, a suppurative otitis media may result.)

Bacterial agents –otitis media:

  • Streptococcus pneumonia,Haemophilus infleunza,Staphylococcus aureus,Group A streptococcus,Moraxella catarhalis.
  • Others chlamydia trachomatis,mycoplasma pneumonie,diphtheritic otitis,mycobacterial tb and chelonae.

Clinical Course:

  • Acute otitis media is defined by the presence of fluid in the middle ear along with signs/symptoms of acute illlness.
  • Signs and symptoms may be specific eg ear pains, ear discharge, hearing loss; or non specific eg fever, irritability, lethargy.
  • Vertigo, nystagmus, tinnitus can also occur.
  • Fluid can persist in the middle ear for prolonged periods after onset of acute otitis media even though symptoms may resolve within a few days of intiation of antimicrobial treatment.
  • The common causes of otitis media are recovered frequently in cultures.
  • However if the patient is toxic or has focal infection elsewhere, culture of the blood and the focus are warranted.
  • Needle aspirations of the middle ear fluid (tympanocentesis) can be done in critically ill patients, the patient who has not responded to the initial antimicrobial therapy in 48-72 hrs and is toxic, and patient with altered host defences eg immunological defect including the newborns.

Treatment:

  • Amoxicillin-clavulanate, cefuroxime, cefixime, erythromycin.
  • Role of oral and nasal decongestants given alone or in combination with antihistamine-may relieve obstruction of the eustachian tube.

Chronic otitis media:

  • This term includes recurrent episodes of acute infection and prolonged duration of middle ear effusions usually resulting from a precious episode of acute infection.
  • Recurrent episodes of acute infection can be managed by chemoprophylaxis (eg amoxicillin given in winter and spring) and immunoprophylaxis = pneumococcal vaccination.
  • Middle ear effusions can be managed surgically.
  • This can be by Myringotomy- incision of the tympanic membrane, adenoidectomy, and insertion of tympanostomy tubes.
  • The proximity of the mastoid to the middle ear cleft suggests that most cases suppurative otitis media are associated with inflammation of the mastoid air cells.
  • Hyperaemia, edema, serous then purulent exudate collects in the cells.
  • Bone necrosis due to pressure of the exudate.
  • Acute mastoiditis is usually accompanied by acute infection in the middle ear.
  • Specific features of mastoiditis include swelling, redness and tenderness over the mastoid bone; pinna is displaced outward and downward and a purulent discharge may be seen after perforation of the tympanum.

Diagnosis:

  • Specimen- pus discharge from ear, freshly from the tympanic membrane.
  • If the tympanic membrane is not perforated,tympanocentesis should be performed to obtain specimen from middle ear.
  • Cultures for bacteria.

Treatment:

  • Antibiotics are similar as those used in otitis media.
  • If the disease in the mastoid has had a prolonged course, cover for staph aureus and Gm neg enteric bacilli for initial therapy until culture results ready.
  • Mastoidectomy- when mastoid abscess forms and sepsis has been controlled by antibiotics.

Summary of pus Examination:

  • DAY1;
  • Description of specimen macroscopically- colour, blood stain.
  • Culture on BA/Mac/Neomycin blood agar if anaerobic infection suspected/LJ media for recurrent or chronic otitis media/SDA.
  • Gram smear –pus cells and bacteria.
  • ZN smear/KOH preparation/Darkfield mic.

Pus Exam:

  • DAY 2 onwards;
  • Examine and report cultures

Complications of Ear Piercing:

}Infection is one of the most common complications of ear piercing. Although skin organisms are the most likely culprits, P aueruginosa infection should be kept in mind for cases that do not respond promptly to antibiotics.

Auricular chondoritis can be slow to heal and may require aggressive therapy, including surgical debridement and drainage.50 Empirical therapy should include coverage for P aueruginosa.

Differentiation of infection from metal sensitivity may be challenging.50 Itching is more likely to predominate over pain when a patient presents with a red ear following piercing. Removal of the stud is recommended.

Eczematous Otitis Externa:

Cellulitis of the external ear may result from trauma, infected atopic dermatitis, or ear piercing. Infections of the earlobe tend to be relatively minor and are generally due to S. aureus, and respond to local measures of cleansing and warm compresses and oral anti staphylococcal antibiotics.

More serious infections that involve the upper ear and its cartilage are associated with high risk for cosmetic deformation. Infections from ear cartilage piercing are most often due to Pseudomonas aeruginosa.23 Wound culture is important to guide therapy.

Empirical intravenous antibiotic coverage for P. aueruginosa, S. aureus, and group A streptococcus is often recommended to lessen the chance of a poor cosmetic result. Cefepime, piperacilline.