Otorhinolaryngology Quiz: Ear Anatomy and Conditions

Affections of External Ear

• The external ear consists of the auricle and external auditory canal (EAC).
• The auricle (pinna) is primarily fibroelastic cartilage, except for the lobule which contains fat.
• The EAC extends from the lateral part of the tympanic membrane (TM) to the external auditory meatus.
• The EAC is about 2.5 cm long.
• The EAC has an outer cartilaginous and inner bony part.
• The cartilaginous part of the EAC contains thick skin, hair follicles, sebaceous and apocrine glands.
• The bony part of the EAC has thin skin and lacks hair follicles and glands.
• The TM is pearly white in appearance.
• The TM has three layers: cuticular, fibrous, and mucous.

Congenital Anomalies of External Ear

• Microtia: A congenital deformity where the pinna is malformed and underdeveloped.
• Associated with anomalies in the middle and inner ear.
• Can be unilateral or bilateral.
• Hearing loss is common.
• Macrotia: Characterized by an excessively large pinna.
• The most exaggerated part is the scaphoid fossa.

Preauricular Sinus/Pit

• A blind-ending narrow pit or tube, due to a failure of fusion of auricular hillocks.
• Classified into three types based on location: the crus, superior area of the crus, and the cymba concha.
• Most are harmless but can become infected, forming retention cysts and causing chronic discharge.

Congenital Atresia of EAC

• Can occur alone or with microtia.
• When occurring alone, it's due to failure of canalization of the ectoderm core filling the dorsal part of the first brachial cleft.
• When associated with microtia, it's frequently accompanied by middle and inner ear abnormalities.
• The EAC may be absent or present as a blind pit.
• Management includes imaging (CT scan of temporal bone), hearing aids, and surgery.

Keloids/Hypertrophic Scars

• A painless mass that forms after trauma or ear piercing.
• Common on the lobule and helix.
• Benign lesions.
• More frequent in people of African descent.
• Firm and round.
• Cosmetic concerns are the primary issue.
• Treatment strategies vary depending on size: topical triamcinolone for smaller keloids and surgical excision with primary closure for larger lesions, using massage and intra-lesion steroids for prevention of recurrence.

Perichondritis

• Inflammation of the perichondrium (the tissue surrounding cartilage) of the auricle.
• Often caused by infection (secondary to hematoma, laceration, surgical incision, or extension from otitis externa).
• Etiological organism is usually Pseudomonas.
• Clinical presentation: severe ear pain, erythema, induration, tenderness of the pinna, possible fluctuation indicating abscess formation and possible chondritis.
• Treatment involves early systemic antibiotics (like ciprofloxacin), drainage, removing necrotic tissue, and packing with antibiotic-impregnated gauze to address abscess formation.
• Delayed treatment can lead to the complication of cauliflower ear (deformity).

Otitis Externa

• Inflammation/infection of the external auditory canal (EAC).
• Common in both genders, with a peak incidence in individuals aged 21-30, often linked to increased outdoor activity.
• Frequent in tropical climates and summer due to increased humidity.
• Risk factors include environmental factors (high temperature and humidity), skin diseases (psoriasis, eczema), EAC abnormalities (exostoses, hairy EAC, stenosis), trauma, presence of foreign bodies (cerumen, hearing aids removal). Endogenous factors include a lack or overproduction of cerumen, systemic illnesses like diabetes mellitus, and immunosuppression.
• Classified as localized (e.g., furunculosis) or diffuse and malignant.
• Causative agents include bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus and fungi.
• Clinical findings include intense ear pain disproportionate to the lesion, reduction in hearing, tragal tenderness, localized EAC swelling, and possible purulent discharge if the swelling ruptures. Preauricular lymphadenopathy can also be observed.
• Management includes aural toilet (using 3% hydrogen peroxide), antibiotic therapy (ampiclox or amoxiclav), analgesics (paracetamol or ibuprofen), and incision and drainage if necessary. Diffuse otitis externa is characterized by inflammation extending to the pinna and tympanic membrane.

Keratosis Obturans

• Abnormal buildup of keratin in the medial portion of the EAC.
• Typically affects adults between 30 and 60 years old.
• Pathophysiology involves faulty epithelial migration and excessive production of epithelium cells.
• Presents as severe ear pain in the osseous part, conductive hearing loss, tinnitus, and a pearly white mass of keratin material with granulation tissue, ulceration, and dilatation of the EAC.
• Treatment options encompass keratolytic agents like salicylic acid, surgical removal under general anesthesia, and canalplasty for recurrent cases, followed by histopathology to rule out malignancy.

Tympanic Membrane Trauma

• Damage to the tympanic membrane (TM) can result from direct force (e.g., foreign body insertion), sudden changes in air pressure (e.g., a loud noise), pressure from fluids (e.g., diving), or temporal bone fractures.
• Trauma often leads to TM perforation.
• Classification is based on duration (acute < 3 months; chronic ≥ 3 months) and presence of discharge (dry or wet).
• Perforation size (small, medium, large) and location (central, marginal) are also considered.
• Symptoms include bleeding, ear pain, ear fullness, conductive or mixed hearing loss, and tinnitus.
• Physical examination involves assessing the TM perforation's location and size, and the presence of fresh blood or CSF leakage for skull base fracture diagnosis.
• Potential complications include ossicular discontinuity, facial nerve injury, and chorda tympani nerve injury. Management typically involves maintaining ear cleanliness and dryness, analgesics, and in cases of persistent perforation, treatment to address potential complications and tympanoplasty.

Fungal Otitis Externa (Otomycosis)

• A fungal infection of the external auditory canal (EAC).
• Causative organisms include Aspergillus nigra (black), Aspergillus fumigatus (brown), and Candida albicans (white/creamy).
• Often occurs in hot, humid environments.
• Secondary infections can arise due to prolonged antibiotic use.
• Symptoms include intense itching, pain, watery discharge with a musty odor, and a canal with a black/grey/white fungal mass, depending on the organism.
• Treatment combines aural toilet, topical antifungal agents (like clotrimazole or ketoconazole), and analgesics. Maintaining ear dryness is important.

Herpes Zoster Oticus

• Viral infection of the EAC, middle ear, and inner ear caused by reactivation of the varicella-zoster virus.
• Predisposing factors include reduced cell-mediated immunity, immunocompromised states, physical or psychological stress.
• Manifestations include vesicles on the tympanic membrane, meatal skin, concha, and the postauricular groove, severe ear pain, ear discharge, facial nerve involvement (CN 7 and 8), and possible Ramsay Hunt syndrome (unilateral lower motor neuron facial palsy).
• Treatment typically involves acyclovir, prednisolone (if facial nerve palsy is present), and pain management. Maintaining ear dryness is important.

Keratosis Obturans

• An abnormal accumulation of keratin within the medial portion of the ear canal (EAC).
• Typically found in adults (30-60).
• Pathophysiology includes disrupted epithelial migration and excessive epithelial production.
• Symptoms involve severe osseous ear pain, conductive hearing loss, tinnitus, a pearly white keratinous mass with granulation tissue within or near the EAC, and potential ulceration and widening of the EAC.
• Management addresses the keratinous blockage with keratolytic agents (like salicylic acid), surgical removal (often under general anesthesia), and canalplasty (for recurrent cases); histological examination is needed to rule out potential malignant transformation after sample removal