PATHO OF THE EAR

Acute otitis media

What is an infection of the middle ear resulting in pain and ear fullness?

Infants and children

In which age group is acute otitis media most common?

Viral infection

What is the most common initial cause of acute otitis media?

Serous exudates

What type of fluid is typically produced by a viral middle ear infection?

Red and bulging

How does the tympanic membrane appear in acute otitis media?

Streptococcus pneumoniae, nontypeable H. influenzae, and Moraxella catarrhalis

What are the three primary bacterial agents in suppurative acute otitis media?

Chronic otitis media

What condition results from repeated bouts of acute otitis media with a failure of resolution?

Pseudomonas aeruginosa and S. aureus

What are the two primary causative bacterial agents of chronic otitis media?

Fungus and polymicrobial infections

Besides bacteria, what are two other causes of chronic otitis media?

Perforation of the eardrum

What is a common physical sequela of chronic otitis media?

Ossicles and labyrinth

Chronic otitis media can encroach on which middle ear and inner ear structures?

Mastoid spaces

Into which area of the temporal bone can chronic otitis media spread?

Temporal cerebritis or abscess

What can occur if chronic otitis media penetrates the cranial vault?

Diabetic patients

In which specific patient population is P. aeruginosa otitis media especially aggressive?

Destructive necrotizing otitis media

What aggressive condition results from P. aeruginosa in diabetic ear infections?

Cholesteatoma

What is a benign non-neoplastic cystic lesion in the middle ear or mastoid?

Chronic otitis media

With which condition is cholesteatoma associated?

1 to 4 cm

What is the typical diameter of a cholesteatoma?

Keratinizing squamous or metaplastic mucus-secreting epithelium

What histologically lines a cholesteatoma?

Amorphous keratinous debris

What fills the cystic lesion of a cholesteatoma?

Giant cells

Which cells are produced to engulf necrotic squamous cells after a cholesteatoma cyst ruptures?

Erode the ossicles, labyrinth, and adjacent bone

What can a cholesteatoma do as it progressively enlarges?

Visible neck masses

What can a cholesteatoma occasionally produce as it erodes surrounding soft tissue?

Otosclerosis

What condition involves abnormal bone deposition in the middle ear?

Rim of the oval window

Where does bone deposition typically occur in otosclerosis?

Stapes footplate

Which part of the stapes is anchored by bony overgrowth in otosclerosis?

Bilateral

Is otosclerosis usually unilateral or bilateral?

Fibrous ankylosis

What occurs first to the stapes footplate in the early decades of life in otosclerosis?

Bony overgrowth

What anchors the stapes footplate over time in otosclerosis?

Degree of immobilization of the stapes footplate

What factor determines the severity of hearing loss in otosclerosis?

Autosomal dominant with variable penetrance

What is the genetic transmission pattern for otosclerosis?

Uncoupling of normal bone resorption and bone formation

What process represents the basis for osseous overgrowth in otosclerosis?

Bone resorption followed by fibrosis and vascularization

What are the initial steps of the otosclerotic process in the temporal bone?

Dense new bone

What eventually replaces fibrosis to anchor the stapes footplate?

External ear or pinna

Which part of the ear is lined by squamous cell epithelium?

Squamous cell carcinoma and basal cell carcinoma

Which two tumors commonly occur in the pinna?

Elderly men

In which group does pinna carcinoma tend to occur?

Sun exposure

What is the primary association for squamous cell carcinoma of the pinna?

Middle-aged to elderly women

In which group does ear canal squamous cell carcinoma occur most often?

Not associated

Is ear canal squamous cell carcinoma associated with sun exposure?

Poor prognosis

What is the prognosis for ear canal carcinoma due to potential cranial cavity invasion?

50 percent

What is the 5-year survival rate for ear canal squamous cell carcinoma?

Regional lymph nodes

Where can ear canal carcinoma metastasize?