Otology Practice Questions

Q: What is the function of the stria vascularis?

To produce endolymph. 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." ### **Explanation of the Correct Answer** **Option D (To produce endolymph)** is correct. The primary function of the stria vascularis is the secretion of **endolymph**. It actively transports potassium ions ($K^+$) into the scala media, creating a high potassium concentration and a positive endocochlear potential (+80 mV). This electrochemical gradient is essential for the transduction of sound by hair cells. ### **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 not produced or absorbed by the stria vascularis. * **Option C:** While the stria vascularis is critical for maintaining the ionic environment, its fundamental physiological role in the context of standard ENT textbooks is the **production/secretion** of endolymph. ### **High-Yield Clinical Pearls for NEET-PG** * **Composition of Endolymph:** High in $K^+$ (150 mEq/L) and low in $Na^+$ (5 mEq/L). It resembles intracellular fluid but is found extracellularly. * **Composition of Perilymph:** High in $Na^+$ (140 mEq/L) and low in $K^+$ (4 mEq/L). It resembles extracellular fluid/CSF. * **Waardenburg Syndrome:** Often involves atrophy of the stria vascularis, leading to sensorineural hearing loss. * **Ototoxicity:** Loop diuretics (like Furosemide) act on the stria vascularis, disrupting the ionic balance and causing transient or permanent hearing loss. * **Presbycusis:** "Metabolic" or "Strial" presbycusis is caused by the atrophy of the stria vascularis.

Q: Fluctuating recurring variable sensorineural deafness is seen in:

Perilabyrinthine fistula. ### Explanation **Correct Answer: C. Perilabyrinthine fistula** A **Perilabyrinthine (or Perilymph) fistula** is an abnormal communication between the fluid-filled inner ear (perilymphatic space) and the air-filled middle ear, most commonly occurring at the round or oval window. * **Mechanism:** The leakage of perilymph leads to sudden or episodic changes in inner ear pressure. This results in **fluctuating sensorineural hearing loss (SNHL)** and episodic vertigo. The hearing loss is "variable" because it can worsen with physical exertion, coughing, or sneezing (Valsalva maneuver), which increases intracranial or middle ear pressure. * **Clinical Sign:** A positive **Hennebert’s sign** (vertigo/nystagmus induced by pressure changes in the external ear canal) is a classic finding. **Why other options are incorrect:** * **A & B (Serous otitis media & Haemotympanum):** These conditions involve fluid or blood in the middle ear, which interferes with the ossicular chain's vibration. Therefore, they cause **Conductive Hearing Loss (CHL)**, not sensorineural deafness. * **D (Labyrinthine concussion):** This usually results from head trauma. While it causes SNHL, the hearing loss is typically **sudden and stable** (non-fluctuating) or may gradually improve; it does not present with recurring, variable fluctuations. **High-Yield Clinical Pearls for NEET-PG:** * **Meniere’s Disease** also presents with fluctuating SNHL, but it is characterized by the triad of vertigo, tinnitus, and aural fullness, often with low-frequency SNHL initially. * **Management of Fistula:** Initial management is strict bed rest with head elevation. If symptoms persist, surgical exploration and patching of the windows are required. * **Tullio Phenomenon:** Vertigo induced by loud sounds; often seen in perilymph fistula and Superior Semicircular Canal Dehiscence (SSCD).

Q: All the following are features of Gradenigo's syndrome except?

Flushing of skin over parotid. **Gradenigo’s Syndrome** is a classic clinical triad resulting from **Petrositis** (infection spreading to the petrous apex of the temporal bone), typically as a complication of chronic suppurative otitis media (CSOM). [1] ### Explanation of Options: * **Correct Answer: Flushing of skin over parotid (Option A)** This is the correct answer because it is **not** a feature of Gradenigo’s syndrome. Flushing and sweating over the parotid region during mastication is characteristic of **Frey’s Syndrome** (auriculotemporal nerve injury), usually following parotid surgery. It has no anatomical or pathological link to petrositis. * **Retro-orbital pain (Option B):** This is caused by irritation of the **Trigeminal nerve (Vth cranial nerve)**, specifically the Gasserian ganglion, which lies in Meckel’s cave near the petrous apex. [1] * **VI nerve palsy (Option C):** The **Abducens nerve** passes through **Dorello’s canal** beneath the petrosphenoid ligament. Inflammation at the petrous apex compresses the nerve, leading to lateral rectus palsy and diplopia. [2] * **Persistent ear discharge (Option D):** This represents the underlying **Otorrhoea** associated with the primary middle ear infection/mastoiditis that leads to petrositis. [1] ### Clinical Pearls for NEET-PG: 1. **The Triad:** 1. Abducens (VI) nerve palsy, 2. Retro-orbital pain (V nerve), 3. Otorrhoea. [2] 2. **Anatomy:** Dorello’s canal is the most vulnerable site for the VI nerve in this syndrome. 3. **Investigation:** **MRI** is the gold standard to visualize marrow changes in the petrous apex, though CT shows bone destruction. [1] 4. **Treatment:** Intensive IV antibiotics and surgical drainage (e.g., cortical or radical mastoidectomy with petrous apicectomy). [1]

Q: Which of the following is a feature of Scheibe's syndrome?

Dysplasia of cochlea. ### Explanation **Scheibe’s Dysplasia** (also known as Cochleosaccular Dysplasia) is the most common form of congenital inner ear malformation. It is characterized by a restricted anomaly involving only the **membranous labyrinth**, specifically the **cochlea and the saccule**. **1. Why the correct answer is right:** In Scheibe’s syndrome, the **bony labyrinth is normal**, but there is dysplasia of the organ of Corti and the saccular macula. Because the pathology involves the cochlea (specifically the basal turn), it results in sensorineural hearing loss. Since the question asks for a feature of the syndrome, **Dysplasia of cochlea** is the most accurate description of the underlying pathology. **2. Why the incorrect options are wrong:** * **Abnormality in bony labyrinth:** This is incorrect because Scheibe’s is a *membranous* labyrinthine dysplasia. Radiologically, the bony labyrinth (CT scan) appears completely normal. * **Semicircular canal fistula:** This is typically a complication of chronic suppurative otitis media (cholesteatoma) or trauma, not a feature of congenital inner ear dysplasia. In Scheibe's, the semicircular canals and utricle are usually preserved. * **Middle ear anomaly:** Scheibe’s syndrome is an inner ear pathology. Middle ear anomalies are seen in conditions like Treacher Collins syndrome or Goldenhar syndrome. **3. NEET-PG High-Yield Pearls:** * **Most Common:** Scheibe’s is the most common histopathological finding in congenital deafness. * **Mondini Dysplasia:** Unlike Scheibe’s, Mondini involves both bony and membranous labyrinths (only 1.5 turns of the cochlea instead of 2.5). * **Michel Aplasia:** The most severe form, characterized by complete absence of the inner ear. * **Alexander’s Aplasia:** Involves only the basal turn of the cochlear duct (high-frequency hearing loss). * **Key Distinction:** Scheibe’s = Membranous only; Mondini = Bony + Membranous.

Q: All are true about transverse fracture of the temporal bone except?

Conductive deafness. Temporal bone fractures are traditionally classified as **Longitudinal** (80%) or **Transverse** (20%) based on their relationship to the long axis of the petrous bone. ### **Why "Conductive Deafness" is the Correct Answer (The Exception)** Transverse fractures typically run perpendicular to the petrous ridge, crossing the bony labyrinth (cochlea and vestibule) and the internal auditory canal. This results in **Sensorineural Hearing Loss (SNHL)** and severe vertigo due to direct damage to the inner ear structures. **Conductive deafness** is a hallmark of *longitudinal* fractures, where the fracture line involves the middle ear, causing ossicular disruption or tympanic membrane rupture. ### **Analysis of Other Options** * **A. Facial nerve commonly involved:** True. Facial nerve paralysis occurs in approximately **50%** of transverse fractures (compared to only 15-20% in longitudinal) because the fracture line often crosses the fallopian canal or internal auditory meatus. * **B. Sensorineural deafness:** True. As the fracture line transects the cochlea or the 8th cranial nerve, permanent SNHL is the expected outcome. * **D. These fractures are less common:** True. Transverse fractures account for only about **20%** of all temporal bone fractures and usually result from severe frontal or occipital blows. ### **High-Yield Clinical Pearls for NEET-PG** | Feature | Longitudinal Fracture (80%) | Transverse Fracture (20%) | | :--- | :--- | :--- | | **Force Direction** | Lateral (Temporal/Parietal) | Frontal or Occipital | | **Hearing Loss** | **Conductive** (Common) | **Sensorineural** (Common) | | **Facial Nerve** | Less common (15-20%) | **More common (50%)** | | **Otics Capsule** | Spared | **Involved** | | **Bleeding** | Bleeding from ear (common) | Hemotympanum (intact TM) | | **CSF Otorrhea** | More common | Less common |

Q: The Phlep sign is seen in which of the following conditions?

Glomus tumor. **Explanation:** The **Phelps sign** (often referred to as the Phlep sign in some Indian medical texts) is a characteristic radiological finding seen in **Glomus Jugulare** tumors. It refers to the **erosion of the bony septum** (the carotico-jugular crest) that separates the jugular bulb from the carotid canal. This sign is best visualized on a high-resolution CT scan of the temporal bone and helps differentiate a glomus tumor from a high-placed jugular bulb. **Analysis of Options:** * **Glomus Tumor (Correct):** These are highly vascular paragangliomas. The Phelps sign indicates the destructive nature of the tumor as it expands from the jugular bulb toward the carotid artery. * **Otosclerosis:** Characterized by the **Schwartze sign** (flamingo flush) on otoscopy and the **Carhart’s notch** at 2 kHz on audiometry. It involves bony remodeling, not large-scale erosion of the jugular crest. * **Meniere’s Disease:** A clinical diagnosis of endolymphatic hydrops. It does not present with bony erosive signs on imaging. * **Lateral Sinus Thrombosis:** A complication of CSOM characterized by the **Griesinger sign** (edema over the mastoid) and the **Delta sign** (empty triangle) on contrast CT, representing a thrombus in the sinus. **NEET-PG High-Yield Pearls for Glomus Tumor:** 1. **Brown’s Sign:** Pulsation of the tympanic membrane seen on otoscopy, which ceases with positive pressure (Siegle’s bulb). 2. **Aquino’s Sign:** Blanching of the tympanic mass upon carotid artery compression. 3. **Clinical Presentation:** Pulsatile tinnitus (most common symptom) and a "rising sun" appearance behind the intact eardrum. 4. **Investigation of Choice:** Contrast-enhanced MRI (shows "salt and pepper" appearance).

Q: The stapes foot plate covers which anatomical structure?

Oval window. **Explanation:** The middle ear functions as an impedance-matching mechanism, transmitting sound vibrations from the air to the fluid-filled cochlea. The **stapes**, the smallest bone in the human body, consists of a head, neck, two crura, and a **footplate**. The footplate is held in the **Oval Window** (Fenestra vestibuli) by the annular ligament. When the stapes vibrates, it pushes the footplate into the oval window, creating pressure waves in the perilymph of the scala vestibuli. **Analysis of Options:** * **A. Round Window (Fenestra Cochleae):** This is located postero-inferior to the oval window and is covered by the **secondary tympanic membrane**. It serves as a pressure release valve; as the stapes pushes into the oval window, the round window membrane bulges outward. * **C. Sinus Tympani:** This is a deep recession on the posterior wall of the tympanic cavity, medial to the pyramid and facial nerve canal. It is a clinically significant site as it is a common hiding spot for **cholesteatoma**. * **D. Pyramid:** This is a hollow conical projection on the posterior wall that houses the **stapedius muscle**. The tendon of the stapedius emerges from its apex to attach to the neck of the stapes. **High-Yield Clinical Pearls for NEET-PG:** * **Otosclerosis:** A condition characterized by pathological bone remodeling that fixes the stapes footplate in the oval window, leading to conductive hearing loss. * **Schwartze Sign:** A flamingo-pink flush seen on the promontory through the TM, indicative of active otosclerosis. * **Stapedectomy:** The surgical treatment for otosclerosis where the fixed footplate is bypassed or removed and replaced with a prosthesis.

Question 1

What is the function of the stria vascularis?

Accepted Answer

To produce endolymph

Answer

To produce perilymph

Answer

To absorb perilymph

Answer

To maintain the ionic composition of endolymph

Question 2

Fluctuating recurring variable sensorineural deafness is seen in:

Accepted Answer

Perilabyrinthine fistula

Answer

Serous otitis media

Answer

Haemotympanum

Answer

Labyrinthine concussion

Question 3

All the following are features of Gradenigo's syndrome except?

Accepted Answer

Flushing of skin over parotid

Answer

Retro orbital pain

Answer

VI nerve palsy

Answer

Persistent ear discharge

Question 4

What is true about the Eustachian tube?

Accepted Answer

It has a higher elastin content in adults.

Answer

Its length is 36 mm in adults and 1.6 mm to 3 mm in children.

Answer

The ventilatory function of the ear is better developed in infants.

Answer

It is more horizontal in adults.

Question 5

Which of the following is a feature of Scheibe's syndrome?

Accepted Answer

Dysplasia of cochlea

Answer

Semicircular canal fistula

Answer

Abnormality in bony labyrinth

Answer

Middle ear anomaly

Question 6

A girl presented with chronic ear discharge, pain on ocular movements, and vertigo, and underwent mastoidectomy. Postoperatively, there was no relief and continuous purulent ear discharge persisted. The patient also had sensorineural hearing loss. What is the most probable diagnosis?

Accepted Answer

Apical petrositis

Answer

Suppurative labyrinthitis

Answer

Serous labyrinthitis

Answer

Lateral sinus thrombophlebitis

Question 7

All are true about transverse fracture of the temporal bone except?

Accepted Answer

Conductive deafness

Answer

Facial nerve commonly involved

Answer

Sensorineural deafness

Answer

These fractures are less common

Question 8

All of the following are true about ear ossicles except?

Accepted Answer

The muscles are highly developed like in bats for echolocation.

Answer

Give the eardrum mechanical advantage via lever action

Answer

Transmit vibrations from tympanic membrane to inner ear

Answer

Are controlled by muscles as part of the acoustic reflex

Question 9

The Phlep sign is seen in which of the following conditions?

Accepted Answer

Glomus tumor

Answer

Otosclerosis

Answer

Meniere's disease

Answer

Lateral sinus thrombosis

Question 10

The stapes foot plate covers which anatomical structure?

Accepted Answer

Oval window

Answer

Round window

Answer

Sinus tympani

Answer

Pyramid

Otology — MCQs

Otology — MCQs

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