Otology Practice Questions

Q: Rinne's test is negative in which of the following conditions?

Chronic suppurative otitis media (CSOM). ### Explanation **Concept of Rinne’s Test** Rinne’s test compares Air Conduction (AC) and Bone Conduction (BC). * **Rinne Positive (Normal/Sensorineural):** AC > BC. This is seen in healthy ears or in Sensorineural Hearing Loss (SNHL). * **Rinne Negative (Conductive):** BC > AC. This occurs when there is a pathology in the external or middle ear that impedes sound conduction. **Why Option B is Correct** **Chronic Suppurative Otitis Media (CSOM)** involves a perforated tympanic membrane and/or ossicular chain damage. This creates a **Conductive Hearing Loss (CHL)**. In CHL, the air conduction pathway is blocked, but the cochlea (tested via bone conduction) remains functional. Therefore, BC becomes louder than AC, resulting in a **Negative Rinne’s test**. **Why Other Options are Incorrect** * **A. Presbycusis:** This is age-related **SNHL**. In SNHL, both AC and BC are reduced, but the relative relationship (AC > BC) is maintained. Thus, Rinne is positive. * **C. Labyrinthitis:** This is an inflammatory condition of the inner ear causing **SNHL**. Rinne remains positive. * **D. Meniere’s Disease:** This involves endolymphatic hydrops affecting the inner ear, leading to **SNHL**. Rinne remains positive. **High-Yield Clinical Pearls for NEET-PG** 1. **The 256 Hz Rule:** A negative Rinne test usually indicates a conductive air-bone gap of at least **15–20 dB**. 2. **False Negative Rinne:** Occurs in severe **unilateral SNHL**. The patient appears to hear the tuning fork better via BC on the affected side because the sound travels through the skull to the *opposite* healthy ear. 3. **Tuning Fork of Choice:** The **512 Hz** fork is preferred for Rinne’s test as it provides the best balance between bone-conduction vibration and decay time.

Q: What is the function of the stria vascularis?

To maintain the electric milieu of endolymph. ### Explanation The **stria vascularis** is a highly vascularized layer of stratified epithelium located on the lateral wall of the cochlear duct (scala media). It is often referred to as the "battery of the cochlea." **Why Option C is Correct:** The primary function of the stria vascularis is to maintain the unique ionic composition and the **endocochlear potential (EP)** of the endolymph. It actively pumps Potassium ($K^+$) ions into the scala media, creating a high concentration of $K^+$ and a positive electrical potential of approximately **+80 mV**. This steep electrochemical gradient is essential for the transduction of sound, as it allows $K^+$ to flow into the hair cells during stimulation. **Analysis of Incorrect Options:** * **Options A & B:** Perilymph is primarily formed as an ultrafiltrate of blood plasma or from cerebrospinal fluid (via the cochlear aqueduct). It is absorbed into the venous plexus of the modiolus. The stria vascularis is specifically associated with **endolymph**, not perilymph. * **Option D:** The electrical milieu of perilymph is relatively neutral (0 mV) and resembles extracellular fluid (high $Na^+$, low $K^+$). The stria vascularis does not regulate this space; the perilymphatic space is maintained by the blood-perilymph barrier. **High-Yield Clinical Pearls for NEET-PG:** * **Composition of Endolymph:** High $K^+$ (150 mEq/L) and low $Na^+$ (2 mEq/L). It is the only extracellular fluid in the body that resembles intracellular fluid. * **Waardenburg Syndrome:** Often involves stria vascularis defects, leading to sensorineural hearing loss due to the absence of melanocytes (which are essential for stria function). * **Ototoxicity:** Loop diuretics (e.g., Furosemide) act on the stria vascularis by inhibiting the $Na^+-K^+-2Cl^-$ cotransporter, leading to a temporary or permanent loss of endocochlear potential.

Q: Teunissen's classification is used for congenital anomalies of which anatomical structure?

Middle ear. **Explanation:** **Teunissen and Cremers Classification** is the standard system used to categorize **congenital middle ear malformations** in patients with an intact tympanic membrane and no external ear canal atresia. The classification is divided into four main classes based on the surgical findings and the specific ossicular chain pathology: * **Class 1:** Isolated stapes ankylosis (congenital stapes fixation). * **Class 2:** Stapes ankylosis combined with other ossicular chain malformations (e.g., incudostapedial joint discontinuity). * **Class 3:** Ossicular chain malformations with a mobile stapes footplate. * **Class 4:** Congenital aplasia or severe dysplasia of the oval or round window. **Why other options are incorrect:** * **Larynx:** Congenital anomalies of the larynx (e.g., Laryngomalacia, Laryngeal webs) are typically classified using systems like the **Benjamin-Inglis classification** (for webs). * **Trachea:** Tracheal anomalies (e.g., Tracheomalacia, Stenosis) use classifications based on the length and site of the segment involved, such as the **Lobeck classification**. * **Pharynx:** Pharyngeal anomalies (e.g., Branchial cleft cysts) are classified based on their embryological origin (1st, 2nd, or 3rd branchial arches). **High-Yield Clinical Pearls for NEET-PG:** 1. **Jahrsdoerfer Scale:** Used to assess candidacy for surgery in patients with **Congenital Aural Atresia** (External Ear). A score of $\geq$ 6 is generally required for surgery. 2. **Most common ossicular anomaly:** The most common isolated ossicular deformity is the **fixation of the stapes footplate**. 3. **Clinical Presentation:** These patients typically present with non-progressive, congenital conductive hearing loss and a normal-looking tympanic membrane.

Q: What is the most common site of perilymph fistula?

Oval window. **Explanation:** A **perilymph fistula (PLF)** is an abnormal communication between the fluid-filled perilymphatic space of the inner ear and the air-filled middle ear cavity. This leakage of perilymph results in sudden or fluctuating sensorineural hearing loss and vertigo. **Why the Oval Window is correct:** The **oval window** is the most common site for a perilymph fistula. Anatomically, it is more vulnerable to barotrauma (sudden pressure changes) or physical trauma because the stapes footplate sits within it, held only by the annular ligament. Rupture typically occurs at this ligamentous interface. Common triggers include heavy lifting, straining (Valsalva maneuver), or sudden atmospheric pressure changes (diving/flying). **Analysis of Incorrect Options:** * **Round Window:** While the second most common site, the round window membrane is generally more resilient than the annular ligament of the oval window. * **Otic Capsule:** This is the dense bone surrounding the inner ear. While fractures of the otic capsule (e.g., temporal bone fractures) can cause perilymph leaks, they are less common than spontaneous or barotrauma-induced leaks at the windows. * **Attic:** The attic (epitympanum) is a part of the middle ear containing the head of the malleus and body of the incus. It is not a site of perilymph containment; therefore, a fistula cannot originate here. **Clinical Pearls for NEET-PG:** * **Hennebert’s Sign:** Vertigo/nystagmus induced by applying pressure to the external auditory canal (positive in PLF and Meniere’s). * **Tullio Phenomenon:** Vertigo induced by loud sounds (seen in PLF and Superior Semicircular Canal Dehiscence). * **Management:** Initial treatment is strict bed rest with head elevation. If symptoms persist, surgical exploration and patching of the windows are indicated.

Q: In the majority of cases with otosclerosis, what is the typical appearance of the tympanic membrane?

Normal. In otosclerosis, the primary pathology is the replacement of normal dense lamellar bone with irregular, vascular spongy bone in the otic capsule, most commonly at the **fissula ante fenestram**. This leads to stapes fixation and conductive hearing loss. **Explanation of Options:** * **A. Normal (Correct):** In the vast majority of patients (approx. 90%), the tympanic membrane appears completely normal on otoscopy. This is because otosclerosis is a disease of the bony labyrinth and ossicles, not the middle ear mucosa or the drum itself. * **B. Flamingo pink:** This refers to **Schwartz’s sign** (or Fleischer's sign). It represents the hypervascularity of the promontory seen through a transparent drum during the active phase of the disease (otospongiosis). While pathognomonic for otosclerosis, it is only seen in about **10% of cases**, making "Normal" the more typical finding. * **C. Blue:** A blue tympanic membrane is characteristic of **Hemotympanum** (blood in the middle ear) or a **High Jugular Bulb/Glomus tumor**. * **D. Yellow:** A yellowish or amber-colored drum is typically seen in **Otitis Media with Effusion (Serous Otitis Media)** due to the presence of sterile fluid. **High-Yield Clinical Pearls for NEET-PG:** 1. **Gelle’s Test:** Negative (indicates stapes fixation). 2. **Carhart’s Notch:** A characteristic dip in the bone conduction threshold at **2000 Hz**. 3. **Bezold’s Triad:** Includes (a) Raised bone conduction threshold, (b) Negative Rinne, and (c) Prolonged Schwabach test. 4. **Treatment of Choice:** Stapedotomy (using a Teflon piston). 5. **Paracusis Willisi:** A clinical feature where the patient hears better in noisy surroundings.

Q: Which structure of the inner ear produces endolymph?

Secreted by the stria vascularis. **Explanation:** The correct answer is **B. Secreted by the stria vascularis.** **1. Why the correct answer is right:** Endolymph is the unique fluid found within the membranous labyrinth (scala media). It is actively secreted by the **stria vascularis**, a highly vascularized layer of stratified epithelium located on the lateral wall of the cochlear duct. The stria vascularis acts as a "battery," maintaining the high potassium ($K^+$) concentration and the positive endocochlear potential (+80 mV) necessary for hair cell depolarization. **2. Why the incorrect options are wrong:** * **A. A filtrate of blood serum:** This describes **Perilymph**, which is chemically similar to extracellular fluid or CSF (high $Na^+$, low $K^+$). Perilymph is formed partly as an ultrafiltrate of blood and partly from CSF via the cochlear aqueduct. * **C. Secreted by the basilar membrane:** The basilar membrane is a structural fibrous layer that supports the Organ of Corti; it has no secretory function. * **D. Secreted by hair cells:** Hair cells are sensory receptors that *utilize* the ionic gradient of endolymph to generate nerve impulses; they do not produce the fluid itself. **3. NEET-PG High-Yield Pearls:** * **Composition:** Endolymph is the only extracellular fluid in the body that resembles intracellular fluid (High $K^+$, Low $Na^+$). * **Absorption:** Endolymph is drained via the endolymphatic duct and absorbed by the **endolymphatic sac**. * **Clinical Correlation:** **Meniere’s Disease** (Endolymphatic Hydrops) is caused by either the overproduction or under-absorption of endolymph, leading to the classic triad of vertigo, tinnitus, and sensorineural hearing loss. * **Helicotrema:** The point where the scala vestibuli and scala tympani communicate, allowing perilymph to flow between them.

Question 1

The Crowe-Beck test is positive in which of the following conditions?

Accepted Answer

Lateral sinus thrombophlebitis

Answer

Stage of localization of brain abscess

Answer

Stage of termination of brain abscess

Answer

Otitic hydrocephalus

Question 2

Which of the following statements are true about idiopathic sudden sensorineural hearing loss?

Accepted Answer

Hearing loss occurs within 24 hours.

Answer

Vertigo is always present.

Answer

Carbogen (5% CO2 + 95% O2) is beneficial.

Answer

Hearing loss occurs within 72 hours.

Question 3

Stapedial reflex is absent in:

Accepted Answer

VIIIth nerve lesion

Answer

VIth nerve lesion

Answer

Xth nerve lesion

Answer

Vth nerve lesion

Question 4

Rinne's test is negative in which of the following conditions?

Accepted Answer

Chronic suppurative otitis media (CSOM)

Answer

Presbycusis

Answer

Labyrinthitis

Answer

Meniere's disease

Question 5

What is the function of the stria vascularis?

Accepted Answer

To maintain the electric milieu of endolymph

Answer

To produce perilymph

Answer

To absorb perilymph

Answer

To maintain the electric milieu of perilymph

Question 6

Teunissen's classification is used for congenital anomalies of which anatomical structure?

Accepted Answer

Middle ear

Answer

Larynx

Answer

Trachea

Answer

Pharynx

Question 7

What is the most common site of perilymph fistula?

Accepted Answer

Oval window

Answer

Round window

Answer

Otic capsule

Answer

Attic

Question 8

In the majority of cases with otosclerosis, what is the typical appearance of the tympanic membrane?

Accepted Answer

Normal

Answer

Flamingo pink

Answer

Blue

Answer

Yellow

Question 9

Which structure of the inner ear produces endolymph?

Accepted Answer

Secreted by the stria vascularis

Answer

A filtrate of blood serum

Answer

Secreted by the basilar membrane

Answer

Secreted by hair cells

Question 10

What type of eardrum perforation is considered unsafe?

Accepted Answer

Marginal

Answer

Central

Answer

Paracentral

Answer

Multiple central

Otology — MCQs

Otology — MCQs

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