Otology — MCQs

Otology Indian Medical PG Practice Questions and MCQs

Question 141: A 31-year-old female patient complains of bilateral hearing impairment for the past 5 years. On examination, the tympanic membrane is normal, and the audiogram shows bilateral conductive deafness. Acoustic reflexes are absent. Which of the following constitutes part of the treatment EXCEPT?

A. Hearing aid
B. Stapedectomy
C. Sodium fluoride
D. Gentamicin (Correct Answer)

Explanation: ### Explanation The clinical presentation of a young female with bilateral progressive conductive hearing loss, a normal tympanic membrane, and absent acoustic reflexes is a classic description of **Otosclerosis**. **Why Gentamicin is the Correct Answer (The "Except"):** Gentamicin is an **aminoglycoside antibiotic** known for its significant **vestibulotoxicity**. In ENT, it is used therapeutically for chemical labyrinthectomy in refractory cases of Meniere’s disease to destroy vestibular hair cells. It has no role in treating Otosclerosis; in fact, its ototoxic profile could potentially worsen hearing or cause vestibular dysfunction. **Analysis of Other Options:** * **A. Hearing Aid:** This is the safest non-surgical management option for patients who do not wish to undergo surgery or are unfit for it. * **B. Stapedectomy:** This is the **surgical treatment of choice**. It involves replacing the fixed stapes footplate with a prosthesis to restore the ossicular chain's mobility. * **C. Sodium Fluoride:** This is the **medical treatment** used in the active phase of the disease (Otospongiosis). It inhibits bone resorption and promotes the maturation of spongy bone into dense bone, potentially slowing the progression of sensorineural hearing loss. **Clinical Pearls for NEET-PG:** * **Schwartz Sign:** A flamingo-pink flush seen on the promontory through the TM, indicating active otospongiosis. * **Carhart’s Notch:** A characteristic dip in the bone conduction threshold at **2000 Hz** on an audiogram. * **Gelle’s Test:** Negative in otosclerosis (indicates stapes fixation). * **Stapedial Reflex:** The earliest sign of otosclerosis is the "on-off effect" (diphasic impedance change), followed by total absence of the reflex.

Question 142: A 9-year-old girl presents with painful swelling behind her ear. An MRI reveals mastoiditis. Which of the following structures is most likely to be affected by the inflammation?

A. Transverse sinus (Correct Answer)
B. Petrous part of the temporal bone
C. Middle ear
D. Occipital sinus

Explanation: **Explanation:** The correct answer is **A. Transverse sinus**. **1. Why Transverse Sinus is Correct:** The mastoid air cells are in close anatomical proximity to the **sigmoid sinus** and the **transverse sinus**. In cases of acute or chronic mastoiditis, the inflammatory process can easily spread through the thin bony plate (Trautmann’s triangle) or via retrograde thrombophlebitis of the small emissary veins. This often leads to **Lateral Sinus Thrombophlebitis (LSTP)**, a classic intracranial complication of mastoiditis. While the sigmoid sinus is the most immediate neighbor, it is a direct continuation of the transverse sinus, and both are frequently involved in the same pathological process. **2. Why Incorrect Options are Wrong:** * **B. Petrous part of the temporal bone:** While inflammation can spread here (causing Petrositis/Gradenigo’s Syndrome), it is less common than venous sinus involvement in standard mastoiditis cases. * **C. Middle ear:** The middle ear and mastoid are already connected via the *aditus ad antrum*. Mastoiditis is usually a *sequela* of middle ear infection, not a structure "affected by the spread" of mastoiditis in the context of a complication. * **D. Occipital sinus:** This sinus is located in the attached margin of the falx cerebelli and is anatomically distant from the mastoid air cells. **3. Clinical Pearls for NEET-PG:** * **Griesinger’s Sign:** Edema over the mastoid process due to thrombosis of the mastoid emissary vein (pathognomonic for Lateral Sinus Thrombosis). * **Delta Sign:** Seen on contrast-enhanced CT, indicating a thrombus in the dural sinus. * **Bezold’s Abscess:** Pus escaping the mastoid tip into the sternocleidomastoid muscle. * **Citelli’s Abscess:** Pus tracking into the posterior belly of the digastric muscle.

Question 143: Referred pain in the ear is commonly associated with which of the following conditions?

A. Maxillary carcinoma
B. Nasopharyngeal carcinoma
C. Carcinoma of the tongue (Correct Answer)
D. Malignant otitis externa

Explanation: **Explanation:** Referred otalgia (ear pain in a normal-looking ear) occurs because the sensory nerve supply of the ear is shared with various structures in the head and neck. **Why Carcinoma of the Tongue is correct:** The posterior one-third of the tongue is supplied by the **Glossopharyngeal nerve (CN IX)**. This nerve also gives off the **Jacobson’s nerve** (tympanic branch), which provides sensory innervation to the middle ear. Malignancies involving the base of the tongue or the oropharynx cause irritation of CN IX, leading to pain referred to the ear via Jacobson’s nerve. **Analysis of Incorrect Options:** * **Maxillary Carcinoma:** The maxillary sinus is supplied by the maxillary division of the Trigeminal nerve (V2). While V3 (mandibular) causes referred otalgia via the auriculotemporal nerve, V2 involvement rarely refers pain to the ear. * **Nasopharyngeal Carcinoma:** While it can cause ear symptoms, it typically presents with **conductive hearing loss** due to Eustachian tube blockage (leading to Serous Otitis Media) rather than isolated referred otalgia. * **Malignant Otitis Externa:** This is a primary inflammatory/infectious condition of the external auditory canal itself. The pain is **local**, not referred. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nerves responsible for Referred Otalgia:** * **CN V3 (Auriculotemporal n.):** Dental caries, TMJ arthritis, molar impaction. * **CN IX (Jacobson’s n.):** Tonsillitis, Post-tonsillectomy pain, Base of tongue CA. * **CN X (Arnold’s n.):** Laryngopharyngeal CA, GERD. * **C2, C3 (Greater Auricular n.):** Cervical spondylosis. 2. **Trotter’s Triad (Nasopharyngeal CA):** Conductive deafness, Palatal palsy, and Temporofacial neuralgia. 3. **Rule of Thumb:** In an elderly patient with earache and a normal otoscopy, always examine the upper aerodigestive tract to rule out occult malignancy.

Question 144: All of the following structures are removed during a radical mastoidectomy except?

A. Chorda tympani
B. Incus
C. Posterior meatal wall
D. Stapes (Correct Answer)

Explanation: **Explanation:** In a **Radical Mastoidectomy**, the primary goal is to convert the mastoid antrum, attic, and middle ear into a single, common exteriorized cavity. This procedure is typically indicated for extensive cholesteatoma where hearing preservation is secondary to the complete eradication of disease. **Why Stapes is the Correct Answer:** The **Stapes footplate** (and usually the superstructure) is strictly preserved. Removing the stapes would open the oval window, leading to a perilymph leak and creating a direct pathway for infection into the labyrinth (labyrinthitis), which can cause permanent sensorineural hearing loss and vertigo. **Analysis of Incorrect Options:** * **Incus & Malleus (Option B):** These are routinely removed to ensure all cholesteatoma matrix is cleared from the attic and middle ear. Only the stapes remains to maintain the integrity of the inner ear. * **Posterior Meatal Wall (Option C):** This is a hallmark of "Canal Wall Down" procedures. The bony wall between the external auditory canal and the mastoid is drilled away to create the common cavity. * **Chorda Tympani (Option A):** As it traverses the middle ear space, it is almost always sacrificed during the removal of the disease and the bony partitions. **High-Yield Clinical Pearls for NEET-PG:** * **Structures preserved in Radical Mastoidectomy:** Stapes footplate, Tensor tympani muscle, Eustachian tube orifice, and the Promontory. * **Modified Radical Mastoidectomy (MRM):** Unlike the radical procedure, MRM preserves the **tympanic membrane remnants and functional ossicles** to maintain hearing. * **Bondy’s Procedure:** A specific type of MRM used for attic cholesteatoma where the middle ear space is normal.

Question 145: Facial nerve palsy can be caused by which of the following?

A. Cholesteatoma
B. Multiple sclerosis
C. Mastoidectomy
D. All of the above (Correct Answer)

Explanation: Facial nerve palsy is a common clinical presentation in Otology, and understanding its diverse etiology—ranging from infections and trauma to neurological disorders—is crucial for the NEET-PG exam. **Explanation of Options:** * **Cholesteatoma (Option A):** In Chronic Suppurative Otitis Media (CSOM) of the attico-antral type, cholesteatoma causes bone erosion. The facial nerve is most commonly involved at the **tympanic (horizontal) segment**, where the bony canal is naturally thin or dehiscent. Pressure necrosis or inflammatory toxins lead to nerve palsy. * **Multiple Sclerosis (Option B):** While less common than peripheral causes, MS is a central cause of facial nerve palsy. Demyelination within the brainstem (pons) can affect the facial nerve nucleus or its intramedullary fibers, often presenting as an Upper Motor Neuron (UMN) or Lower Motor Neuron (LMN) lesion depending on the site of the plaque. * **Mastoidectomy (Option C):** Iatrogenic injury is a recognized complication of ear surgery. The nerve is most vulnerable during a mastoidectomy at the **second genu** (near the aditus ad antrum) or within the mastoid segment. **Clinical Pearls for NEET-PG:** 1. **Most common site of injury in Mastoidectomy:** The horizontal semicircular canal is the landmark; the nerve is usually injured just below it at the second genu. 2. **Most common site of idiopathic palsy (Bell’s):** The **labyrinthine segment** (the narrowest part of the fallopian canal). 3. **Grading:** The **House-Brackmann scale** is used to grade the severity of facial nerve palsy (Grade I is normal, Grade VI is total paralysis). 4. **Topognostic tests:** Schirmer’s test (Greater superficial petrosal nerve), Stapedial reflex (Nerve to stapedius), and Taste/Electrogustometry (Chorda tympani) help localize the level of the lesion.

Question 146: What is the most common cranial nerve involved in chronic suppurative otitis media (CSOM)?

A. Cranial Nerve V (Trigeminal)
B. Cranial Nerve VII (Facial) (Correct Answer)
C. Cranial Nerve IX (Glossopharyngeal)
D. Cranial Nerve XI (Accessory)

Explanation: ### Explanation **Correct Answer: B. Cranial Nerve VII (Facial)** **Why it is correct:** The facial nerve (CN VII) has a long and complex course through the temporal bone, specifically within the bony **Fallopian canal**. In Chronic Suppurative Otitis Media (CSOM), particularly the **atticoantral (unsafe) type** involving cholesteatoma, the bony wall of this canal can be eroded by osteoclastic enzymes (e.g., collagenases) or pressure necrosis. The most common site of involvement is the **tympanic (horizontal) segment** of the nerve, which lies just above the oval window. If the canal is naturally dehiscent (a common anatomical variation), the nerve is even more susceptible to infection and inflammation, leading to facial palsy. **Why the other options are incorrect:** * **Cranial Nerve V (Trigeminal):** While the Gasserian ganglion sits near the petrous apex, it is typically only involved in **Gradenigo’s Syndrome** (petrositis), which presents with retro-orbital pain. It is not the most common nerve involved in general CSOM. * **Cranial Nerve IX (Glossopharyngeal):** This nerve exits via the jugular foramen. While it provides sensory innervation to the middle ear (Jacobson’s nerve), motor paralysis of CN IX is not a standard complication of CSOM. * **Cranial Nerve XI (Accessory):** This nerve also exits the jugular foramen and is distant from the middle ear cleft; it is not affected by middle ear suppuration. **Clinical Pearls for NEET-PG:** * **Most common site of dehiscence:** The horizontal segment of the Fallopian canal (above the oval window). * **Management:** If facial palsy occurs in acute otitis media, it is treated medically (myringotomy + antibiotics). If it occurs in **CSOM**, it is a surgical emergency requiring **Urgent Mastoidectomy** to decompress the nerve. * **Gradenigo’s Triad:** Otorrhea + Diplopia (CN VI palsy) + Retro-orbital pain (CN V involvement).

Question 147: Skull base osteomyelitis is:

A. Otomycosis
B. Tumor of the Ear
C. Malignant Otitis Externa (Correct Answer)
D. Chronic serous Otitis Media

Explanation: **Explanation:** **Malignant Otitis Externa (MOE)**, also known as Necrotizing Otitis Externa, is a severe, life-threatening infection of the external auditory canal that spreads to the **skull base**, leading to **Skull Base Osteomyelitis**. 1. **Why the correct answer is right:** MOE is primarily caused by *Pseudomonas aeruginosa* and typically affects elderly diabetic or immunocompromised patients. The infection originates in the external ear canal and spreads through the **Fissures of Santorini** and the tympanomastoid suture to the temporal bone and skull base. This results in osteomyelitis, which can lead to multiple cranial nerve palsies (CN VII is most common, followed by IX, X, and XI). 2. **Why the incorrect options are wrong:** * **Otomycosis:** A superficial fungal infection of the external ear canal (usually *Aspergillus niger* or *Candida*). It does not involve the bone. * **Tumor of the Ear:** While tumors like Squamous Cell Carcinoma can invade the skull base, the term "Skull Base Osteomyelitis" specifically refers to an inflammatory/infectious process, not a neoplastic one. * **Chronic Serous Otitis Media:** This involves non-purulent fluid in the middle ear due to Eustachian tube dysfunction. It is a non-infectious condition and does not cause bone destruction. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic Sign:** Presence of **granulation tissue** at the junction of the cartilaginous and bony external auditory canal. * **Diagnosis:** **Technetium-99m scan** is the most sensitive for initial diagnosis (detects osteoblastic activity). **Gallium-67 scan** is used to monitor response to treatment (detects active infection). * **Treatment:** Long-term intravenous anti-pseudomonal antibiotics (e.g., Ciprofloxacin, Ceftazidime) and strict glycemic control.

Question 148: What is the ossicular ratio?

A. 1.3 : 1 (Correct Answer)
B. 1.2 : 1
C. 1.1 : 1
D. 1 : 1

Explanation: ### **Explanation** The correct answer is **A. 1.3 : 1**. This question pertains to the **impedance matching mechanism** of the middle ear, which ensures that sound energy is efficiently transferred from the air (low impedance) to the fluid of the inner ear (high impedance). Without this mechanism, approximately 99.9% of sound energy would be reflected. #### **The Underlying Concept: Lever Action of Ossicles** The ossicular ratio (also known as the **Lever Ratio**) is derived from the anatomical relationship between the **malleus** and the **incus**. * The handle of the malleus is approximately **1.3 times longer** than the long process of the incus. * Because the malleus acts as a longer lever arm rotating around a fulcrum, it increases the force exerted on the stapes. * **Calculation:** Length of Malleus handle / Length of Incus long process = **1.3 : 1**. #### **Analysis of Incorrect Options** * **Options B, C, and D:** These ratios are mathematically incorrect. A ratio of 1:1 (Option D) would imply no mechanical advantage, leading to significant hearing loss. #### **High-Yield Clinical Pearls for NEET-PG** To master middle ear transformer mechanics, remember these three components: 1. **Areal Ratio (Hydraulic Action):** The most significant factor. The effective area of the tympanic membrane (55 $mm^2$) is much larger than the stapes footplate (3.2 $mm^2$). Ratio = **17 : 1**. 2. **Lever Ratio:** As explained above, this is **1.3 : 1**. 3. **Total Transformer Ratio:** By multiplying the Areal Ratio (17) by the Lever Ratio (1.3), we get a total gain of approximately **22 : 1**. 4. **Decibel Gain:** This mechanical advantage results in a pressure increase of about **25–30 dB**, which compensates for the transition from air to cochlear fluids.

Question 149: Which of the following is NOT true regarding Ramsay Hunt syndrome?

A. Cranial nerve VII is involved.
B. Facial muscles are involved.
C. Facial vesicles are seen. (Correct Answer)
D. Herpes zoster is the etiologic agent.

Explanation: **Explanation:** Ramsay Hunt Syndrome (Herpes Zoster Oticus) is caused by the reactivation of the **Varicella Zoster Virus (VZV)** in the **geniculate ganglion** of the facial nerve. **Why Option C is the correct answer (The "False" statement):** While the syndrome involves a vesicular rash, the characteristic vesicles are typically found on the **pinna (auricle), the external auditory canal, and the soft palate/fauces**, rather than the general facial skin. In NEET-PG, examiners often differentiate between "facial vesicles" (suggestive of Herpes Zoster Ophthalmicus or general shingles) and the specific "otic" distribution of Ramsay Hunt. **Analysis of other options:** * **Option A & B:** The virus resides in the geniculate ganglion of **Cranial Nerve VII**. Reactivation leads to inflammation and compression of the nerve, resulting in lower motor neuron **facial nerve palsy**, which manifests as paralysis of the **facial muscles** on the affected side. * **Option D:** **Herpes Zoster** (reactivated VZV) is indeed the etiologic agent. **High-Yield Clinical Pearls for NEET-PG:** * **Triad:** Ipsilateral facial paralysis, otalgia (ear pain), and vesicles in the auditory canal/auricle. * **Nerve Involvement:** CN VII is most common, but CN VIII is frequently involved, leading to sensorineural hearing loss and vertigo. * **Prognosis:** The facial paralysis in Ramsay Hunt is generally more severe and has a poorer recovery rate compared to Bell’s Palsy. * **Treatment:** Combination of oral Acyclovir/Valacyclovir and systemic corticosteroids.

Question 150: Simple mastoidectomy is indicated for which of the following conditions?

A. Lateral sinus thrombophlebitis
B. Small localized cholesteatoma
C. Acute suppurative otitis media (ASOM)
D. Acute mastoiditis (Correct Answer)

Explanation: **Explanation:** **1. Why Option D is Correct:** Simple Mastoidectomy (Schwartze operation) is a **cortical mastoidectomy** where the mastoid air cells are exenterated without disturbing the posterior meatal wall or the contents of the middle ear. Its primary goal is to provide drainage and remove infected bone in cases of **Acute Mastoiditis** that fail to respond to conservative medical management (antibiotics). It converts the mastoid into a single large cavity, effectively draining the "empyema" of the mastoid. **2. Why Other Options are Incorrect:** * **Option A (Lateral Sinus Thrombophlebitis):** While a mastoidectomy is performed as part of the surgical approach, it usually requires a more extensive procedure to expose the sinus plate and potentially internal jugular vein ligation, rather than just a simple cortical mastoidectomy. * **Option B (Small Localized Cholesteatoma):** Cholesteatoma is a feature of Chronic Suppurative Otitis Media (Attico-antral type). It requires a **Modified Radical Mastoidectomy (MRM)** or Radical Mastoidectomy to ensure complete removal of the squamous epithelium and to create a "trouble-free" ear. Simple mastoidectomy is contraindicated in cholesteatoma as it does not address the middle ear pathology. * **Option C (ASOM):** Most cases of ASOM are managed medically with antibiotics and decongestants. Surgery (Myringotomy) is only indicated if the drum is bulging or if there is severe pain. Mastoidectomy is only considered if ASOM progresses to the complication of Acute Mastoiditis. **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Simple Mastoidectomy:** Acute mastoiditis with reservoir sign, masked mastoiditis, and as a preliminary step in Endolymphatic sac surgery or Cochlear Implantation. * **Boundaries of MacEwen’s Triangle (Suprameatal Triangle):** The surgical landmark for the mastoid antrum. Boundaries: Supramastoid crest (superior), Postero-superior segment of external auditory canal (anterior), and Tangent to the canal (posterior). * **Key Landmark:** The **Henle’s spine** lies at the anteroinferior corner of the MacEwen’s triangle.

Practice by Chapter

Tympanic Membrane Perforation

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Cholesteatoma

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Tympanoplasty Techniques

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Ossicular Chain Reconstruction

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Mastoidectomy

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Stapedectomy

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Implantable Hearing Devices

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Congenital Aural Atresia

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Otologic Trauma

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Glomus Tumors

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Facial Nerve Decompression

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Rehabilitative Audiology

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Otology — MCQs

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