Anatomy, Physiology, and Relevant Pathologies Flashcards

Inventory of outer, middle, inner, retrocochlear, and vestibular disorders along with genetic syndromes as documented in the lecture appendices.

Atresia

Congenital malformation of the external auditory canal due to interrupted development of the outer ear, categorized into Type A (meatal), Type B (partial), Type C (total), and Type D (hypopneumatic).

Exostoses

Broad, round, bony growths occurring in the osseous portion of the EAC, often associated with exposure to cold temperatures (e.g., swimming, diving).

Microtia

A small or misshapen pinna, sometimes occurring as a "peanut" shape; Anotia refers to the complete absence of the pinna.

Herpes zoster oticus (shingles)

Lesions or blisters on the pinna resulting from the chicken pox virus, often accompanied by swelling on the side of the face, facial weakness, and SNHL.

Furunculosis

Raised, reddish lesions at the base of hair follicles on the outer EAC.

Osteoma

Pedunculated benign tumors in the osseous portion of the EAC characterized by growths with a narrow base.

Cholesteatoma

Overproduction of keratin from squamous cell epithelium within the middle ear, most often in the epitympanum; can be acquired through chronic inflammation or related to embryonic epithelial cell nests.

Disarticulation of the ossicular chain

Disruption of the continuity of the ossicles, most often at the incudostapedial joint, yielding a Type Ad tympanogram.

Eustachian tube dysfunction

Failure of the ET to open or chronic closure which prevents middle ear ventilation, creating excess negative pressure and Type C tympanograms.

Glomus tumor (paraganglioma)

Tumors arising from paraganglion cells in the jugular bulb or adjacent to Arnold's or Jacobson's nerve, often causing pulsatile tinnitus and showing Brown's sign during otoscopy.

Otosclerosis

Metabolic alteration of the temporal bone in the otic capsule where the stapes footplate becomes mineralized around the oval window; common signs include Schwartze's sign and Carhart's notch.

Carhart's notch

An audiometric finding associated with otosclerosis consisting of CHL with a SNHL-like dip at $2\,kHz$.

Tympanosclerosis

White calcified plaques on the tympanic membrane, primarily asymptomatic but may result in Type As tympanograms.

Autoimmune inner ear disorder

A progressive or fluctuating SNHL caused by the body's immune response directed at the inner ear, common in middle-aged women.

Enlarged vestibular aqueduct syndrome (EVAS)

A condition where the vestibular aqueduct within the temporal bone is abnormally large, typically diagnosed around age $3-4$ and associated with fluctuating/progressive SNHL.

Hidden hearing loss

Abnormalities in the inner hair cells or ribbon synapses of the cochlea due to noise exposure, presenting with normal hearing thresholds but difficulty with speech in noise and missing/reduced wave I on ABR.

Meniere's disease

A labyrinthine disorder caused by excess endolymph fluid pressure characterized by roaring tinnitus, episodic vertigo, aural fullness, and unilateral low-frequency SNHL.

Ototoxicity

Degeneration of cochlear hair cells and auditory nerve due to toxic medications or chemicals, resulting in bilateral progressive high-frequency SNHL.

Perilymphatic fistula

A leak of perilymph from the oval or round window altering pressure differences between the scalae, often resulting in Hennebert's sign (nystagmus during pressure changes).

Superior semicircular canal dehiscence (SSCD)

Thinning or opening of the bony covering of the superior semicircular canal, creating a fistula and symptoms like autophony and Tullio's (vertigo to loud sounds).

Auditory neuropathy spectrum disorder (ANSD)

Impaired function of the auditory nerve where OAEs are present but ABR is absent or highly abnormal with cochlear microphonic (CM) only.

Vestibular schwannoma

A benign tumor of the vestibular branch of CN VIII originating from Schwann cells, often characterized by positive reflex decay and unilateral SNHL with positive rollover.

Benign paroxysmal positional vertigo (BPPV)

Sudden onset vertigo lasting $30-60\,seconds$ provoked by head movements such as lying down or rolling over in bed.

Mal de debarquement syndrome

Persistent rocking sensation (without imbalance) following prolonged travel, typically relieved when the person is in motion.

Alport syndrome

A primarily X-linked genetic disorder characterized by kidney abnormalities (glomerulonephritis), abnormal retina color, and progressive SNHL.

CHARGE syndrome

An autosomal dominant disorder identified by Coloboma, Heart defects, Atresia chonae, Retarded growth, Genital abnormalities, and Ear anomalies (SNHL or MHL).

Jervell & Lange-Nielsen syndrome

An autosomal recessive disorder characterized by a prolonged heart QT interval, repeated syncope attacks, and profound bilateral SNHL.

Pendred syndrome

An autosomal recessive disorder featuring goiter (enlarged thyroid) and bilateral high-frequency progressive SNHL associated with enlarged vestibular aqueducts.

Stickler syndrome

An autosomal dominant disorder characterized by a flat facial profile, musculoskeletal issues, retinal detachment, and SNHL of varying severity (Types 1-3).

Usher syndrome

An autosomal recessive disorder characterized by dual sensory loss: retinitis pigmentosa (progressive eye disease) and bilateral SNHL.

Waardenburg syndrome

A genetic disorder characterized by white forelock, heterochromia, and nonprogressive SNHL; Types I and II are autosomal dominant.