Neurotology Practice Questions

Q: MRI Brain of a 40-year-old patient with progressive unilateral SNHL and tinnitus is shown below. Which is the most common extracanalicular nerve to be involved?

V. ***V*** - The image shows a large **right cerebellopontine angle (CPA) mass**, consistent with an **acoustic neuroma** (vestibular schwannoma), which commonly arises from CN VIII in the internal auditory canal and extends into the CPA. - The **trigeminal nerve (CN V)** is the most common extracanalicular cranial nerve to be compressed and involved by larger CPA tumors due to its proximity and superior-anterior position relative to CN VIII. *VI* - The abducens nerve (CN VI) controls the lateral rectus muscle of the eye, and its involvement typically causes **diplopia** and **lateral gaze palsy**. While possible with very large and medially extending CPA tumors, it is less common than CN V involvement. - CN VI is located more medially and anteriorly within the brainstem and generally requires significant mass effect rather than direct compression from a typical CPA tumor. *VII* - The facial nerve (CN VII) travels with the vestibulocochlear nerve (CN VIII) through the **internal auditory canal**, and is frequently involved by acoustic neuromas within the canal, leading to **facial weakness or paralysis**. - However, the question specifically asks for the most common **extracanalicular** nerve involvement. While CN VII is intimately associated, its most common site of involvement is within the canal, or early in the CPA, and V is often implicated with larger CPA masses. *VIII* - The vestibulocochlear nerve (CN VIII) is the nerve from which **acoustic neuromas (vestibular schwannomas)** originate, causing the presenting symptoms of **unilateral SNHL and tinnitus**. Therefore, it is the primary affected nerve, not an extracanalicular one involved due to compression. - The question asks for the most common **extracanalicular nerve to be involved**, implying a nerve *other than* the one the tumor originates from or primarily affects locally within the canal.

Q: A patient presents with conductive hearing loss, pulsatile tinnitus and a positive Phelps sign. Using the CT scan provided, identify the condition.

Glomus jugulare. ***Glomus jugulare*** - This diagnosis aligns with the presence of **conductive hearing loss**, **pulsatile tinnitus**, and a **positive Phelps sign**, which indicate a highly vascular tumor in the jugular foramen. - While exact details of the CT scan are difficult to discern from the provided image, the clinical context strongly points towards a **glomus jugulare tumor**, known for its characteristic bone erosion around the jugular bulb seen on imaging. *Glomus tympanicum* - This typically presents with **pulsatile tinnitus** and **conductive hearing loss**, but is usually observed as a red mass behind an intact tympanic membrane, arising from the **promontory** within the middle ear space. - It would not typically cause a **Phelps sign**, which specifically relates to erosion of the jugular foramen region. *Acoustic neuroma* - An acoustic neuroma (vestibular schwannoma) causes **sensorineural hearing loss**, often unilateral, not conductive, along with **tinnitus** (usually non-pulsatile) and **balance issues**. - It arises from the vestibular nerve within the **internal auditory canal** and cerebellopontine angle, and does not cause a Phelps sign. *Otosclerosis* - Otosclerosis is characterized by **conductive hearing loss** due to abnormal bone growth fixing the stapes in the oval window, but it does not cause **pulsatile tinnitus** or involve a **positive Phelps sign**. - The disease involves the **otic capsule** and typically does not present with a tumorous mass visible on CT in the jugular foramen area.

Q: A patient presents with conductive hearing loss, pulsatile tinnitus, and a positive Phelps sign. Based on the CT scan image provided, what is the most likely diagnosis?

Glomus Jugulare. ***Glomus Jugulare*** - The symptoms of **conductive hearing loss**, **pulsatile tinnitus**, and a **positive Phelps sign** (destruction of the bone separating the carotid artery from the jugular bulb on CT) are classic for a glomus jugulare tumor. - The CT scan image, showing a destructive lesion in the **jugular foramen** region, further supports this diagnosis, as these tumors originate from the paraganglia of the jugular bulb. *Glomus Tympanicum* - While it can cause conductive hearing loss and pulsatile tinnitus, a glomus tympanicum tumor is typically **confined to the middle ear cavity** and does not involve bone erosion of the jugular foramen as indicated by a positive Phelps sign. - The CT findings would show a mass in the middle ear, often behind an intact tympanic membrane, rather than extensive bone destruction in the jugular region. *Acoustic Neuroma* - This tumor, also known as a **vestibular schwannoma**, primarily causes **sensorineural hearing loss**, **tinnitus** (often non-pulsatile), and **balance issues**, not conductive hearing loss or pulsatile tinnitus. - An acoustic neuroma is located in the **cerebellopontine angle** and internal auditory canal, and the CT scan would show a mass in this specific location, not necessarily bone erosion of the jugular foramen. *Cholesteatoma* - A cholesteatoma is a **destructive, expanding growth of keratinizing squamous epithelium** in the middle ear or mastoid, typically presenting with **conductive hearing loss**, **otorrhea**, and sometimes headaches. - It does not typically cause pulsatile tinnitus unless it's very large and vascularized, nor does it present with the characteristic destruction of the jugular foramen seen with a positive Phelps sign.

Q: The commonest cranial nerve involved in acoustic neuroma is:

VIII. ***Correct Answer: VIII (Vestibulocochlear Nerve)*** - Acoustic neuroma, also known as **vestibular schwannoma**, arises from the **Schwann cells** of the **vestibular branch of cranial nerve VIII**. - Its symptoms, such as **hearing loss**, **tinnitus**, and **balance problems**, directly result from the compression and dysfunction of the vestibulocochlear nerve. - This is the **primary nerve involved** as the tumor originates from it. *Incorrect: X (Vagus Nerve)* - The **vagus nerve (cranial nerve X)** is involved in diverse functions like **swallowing, phonation, and parasympathetic innervation of organs**. - While a large acoustic neuroma can eventually affect adjacent cranial nerves, it is not the primary nerve involved or the origin of the tumor. *Incorrect: IX (Glossopharyngeal Nerve)* - The **glossopharyngeal nerve (cranial nerve IX)** is primarily responsible for **taste, salivation, and sensation from the pharynx**. - Involvement of this nerve typically presents with symptoms like **dysphagia** or altered taste, which are not initial or common features of an acoustic neuroma. *Incorrect: VI (Abducens Nerve)* - The **abducens nerve (cranial nerve VI)** controls the **lateral rectus muscle**, responsible for moving the eye outward. - Involvement would lead to **diplopia** or a convergent squint, which occurs only in very large acoustic neuromas that cause significant brainstem compression.

Q: Earliest reflex lost in acoustic neuroma -

Stapedial. Stapedial - The stapedial reflex (also known as the acoustic reflex) involves the contraction of the stapedius muscle in response to loud sound, which stiffens the ossicular chain. - This reflex arc utilizes the facial nerve (VII), whose fibers are often the first to be compressed as an acoustic neuroma (vestibular schwannoma) grows in the cerebellopontine angle, leading to its early impairment [1]. Corneal - The corneal reflex tests the integrity of the trigeminal nerve (V) (afferent) and the facial nerve (VII) (efferent) by touching the cornea. - While cranial nerves V and VII can be affected by larger acoustic neuromas, the stapedial reflex typically shows impairment earlier due to the proximity of the facial nerve at the internal auditory meatus [1]. Pupillary - The pupillary light reflex involves the optic nerve (II) (afferent) and the oculomotor nerve (III) (efferent), controlling pupil constriction [2]. - This reflex is generally unaffected by an acoustic neuroma, as the involved cranial nerves are distant from the tumor's location in the cerebellopontine angle [2], [3]. Gag reflex - The gag reflex primarily involves the glossopharyngeal nerve (IX) (afferent) and the vagus nerve (X) (efferent), which are located more inferiorly in the brainstem. - While very late-stage or large acoustic neuromas can compress nerves IX and X, this reflex is typically preserved until significant tumor growth, making it a much later sign than stapedial reflex loss.

Q: Which of the following is not true regarding Vestibular neuroma

Normal Corneal reflex. ***Absence of caloric response*** - A **vestibular schwannoma** (acoustic neuroma) typically arises from the **vestibular nerve**, causing early impairment of **vestibular function**. - This often manifests as a **reduced or absent caloric response** in the affected ear, indicating damage to the peripheral vestibular system. *Normal Corneal reflex* - The **corneal reflex** tests the integrity of the **trigeminal nerve (CN V)** for the afferent limb and the **facial nerve (CN VII)** for the efferent limb. - While a large vestibular schwannoma can compress the trigeminal nerve and cause a diminished corneal reflex, early-stage tumors, or smaller tumors less commonly lead to this finding. *Nystagmus* - **Nystagmus** is an involuntary rhythmic eye movement and can be a sign of **vestibular dysfunction**, which is characteristic of a vestibular schwannoma. - It often presents as a **vestibular nystagmus**, which can be spontaneous or provoked, particularly in the early stages as the tumor affects balance pathways. *High frequency sensorineural deafness* - **Sensorineural hearing loss** is a classic and often the earliest symptom of a vestibular schwannoma, as the tumor compresses the **cochlear nerve**. - The hearing loss typically affects **higher frequencies** first and is progressive and unilateral.

Q: True about acoustic neuroma:

Arises from vestibular nerve. ***Arises from vestibular nerve*** - An **acoustic neuroma**, also known as a **vestibular schwannoma**, is a benign tumor that originates from the **Schwann cells** of the **vestibular nerve (cranial nerve VIII)**. - This tumor typically grows in the **internal auditory canal** and cerebellopontine angle. *Malignant tumour* - Acoustic neuromas are almost always **benign tumors**, meaning they are non-cancerous and do not typically spread to other parts of the body. - While they are benign, their growth can compress adjacent nerves and brain structures, leading to significant neurological deficits. *Upper pole compresses IX,X,XI nerves* - The **glossopharyngeal (IX), vagus (X), and accessory (XI) nerves** originate lower in the brainstem and are more commonly compressed by tumors in the **jugular foramen** region, not typically by the upper pole of an acoustic neuroma. - An acoustic neuroma primarily affects the **vestibulocochlear nerve (VIII)** and, if large enough, the **facial nerve (VII)** and **trigeminal nerve (V)** in the **cerebellopontine angle**. *Lower pole compresses trigeminal cranial nerve* - The **trigeminal nerve (V)** is located more superiorly and medially in the **cerebellopontine angle** relative to the usual growth pattern of an acoustic neuroma. - Compression of the trigeminal nerve by an acoustic neuroma is more likely to occur with a **large tumor** expanding into the superior part of the cerebellopontine angle, rather than by its lower pole.

Q: Acoustic neuroma causes:

Retrocochlear deafness. ***Retrocochlear deafness*** - An acoustic neuroma is a **benign tumor** that grows on the **vestibulocochlear nerve (cranial nerve VIII)**, which is responsible for hearing and balance. - As the tumor grows, it compresses the nerve, causing **sensorineural hearing loss** that originates distal to the cochlea and is therefore termed retrocochlear. *Any of the above* - This option is incorrect because acoustic neuromas specifically cause **retrocochlear deafness**, not all types of hearing loss. - The type of deafness is defined by the **location of the lesion**, and acoustic neuromas compress the nerve beyond the cochlea. *Conductive deafness* - **Conductive deafness** results from problems in the outer or middle ear that prevent sound waves from reaching the inner ear. - Acoustic neuromas affect the **nerve itself** (inner ear/brain pathway), not the sound conduction mechanisms of the outer or middle ear. *Cochlear deafness* - **Cochlear deafness** is a type of sensorineural hearing loss originating within the **cochlea** (inner ear). - While an acoustic neuroma causes sensorineural hearing loss, the lesion is **distal to the cochlea** (on the nerve), making it retrocochlear rather than cochlear.

Q: All of the following are true about glomus-jugulare tumor except:

Most commonly affects male. ***Most commonly affects male*** - **Glomus jugulare tumors** are more common in **females** (3:1 to 5:1 ratio), making this statement **incorrect**. - This tumor type is related to **paragangliomas** and typically affects middle-aged individuals, with a clear predilection for the female sex. *Are paragangliomas* - **Glomus jugulare tumors** are indeed **paragangliomas**, arising from neuroendocrine cells (chemoreceptor cells) of the jugular bulb. - These are **chemodectomas**, originating from neural crest cells associated with the parasympathetic nervous system. *Arises from the adventitia of jugular bulb* - **Glomus jugulare tumors** arise from the **paraganglia in the adventitia of the jugular bulb**. - These are **glomus bodies** (chemoreceptor tissue) located in the temporal bone, specifically in the jugular foramen region. *Pulsatile tinnitus and conductive deafness seen* - **Pulsatile tinnitus** is a classic symptom due to the tumor's highly vascular nature and proximity to the ear. - **Conductive hearing loss** can result from the tumor encroaching on the middle ear ossicles or filling the tympanic cavity.

Q: If in a patient of acoustic neuroma, corneal reflex is absent it implies involvement of cranial nerve:

5th. ***5th*** - The **corneal reflex** tests the integrity of the **trigeminal nerve (CN V)** for the afferent (sensory) pathway, detecting touch on the cornea [1]. Its absence indicates dysfunction of this nerve. - An **acoustic neuroma**, growing in the **cerebellopontine angle**, can compress adjacent cranial nerves, including the trigeminal nerve, leading to sensory deficits like an absent corneal reflex. *None of the options* - This option is incorrect because the **corneal reflex** directly evaluates specific cranial nerves, and its absence strongly points to involvement of one or more of them. - The symptoms described are classic neurological findings that can be localized to a specific nerve. *Both* - While both the trigeminal (CN V) and facial (CN VII) nerves are involved in the corneal reflex, the **afferent limb (sensory perception)** is primarily mediated by the trigeminal nerve [1]. - The efferent limb (motor response of blinking) is mediated by the facial nerve, but the absence of the reflex points to the sensory input problem [1]. *7th* - The **facial nerve (CN VII)** is responsible for the **efferent (motor) component** of the corneal reflex, causing the eyelids to close [1]. - While a lesion of the facial nerve would impair the blinking response, the primary issue when the stimulus is not perceived (leading to an absent reflex altogether) is generally a problem with the **trigeminal nerve's sensory function**.

Question 1

MRI Brain of a 40-year-old patient with progressive unilateral SNHL and tinnitus is shown below. Which is the most common extracanalicular nerve to be involved?

Accepted Answer

V

Answer

VI

Answer

VII

Answer

VIII

Question 2

A patient presents with conductive hearing loss, pulsatile tinnitus and a positive Phelps sign. Using the CT scan provided, identify the condition.

Accepted Answer

Glomus jugulare

Answer

Glomus tympanicum

Answer

Acoustic neuroma

Answer

Otosclerosis

Question 3

A patient presents with conductive hearing loss, pulsatile tinnitus, and a positive Phelps sign. Based on the CT scan image provided, what is the most likely diagnosis?

Accepted Answer

Glomus Jugulare

Answer

Glomus Tympanicum

Answer

Acoustic Neuroma

Answer

Cholesteatoma

Question 4

The commonest cranial nerve involved in acoustic neuroma is:

Accepted Answer

VIII

Answer

X

Answer

IX

Answer

VI

Question 5

Earliest reflex lost in acoustic neuroma -

Accepted Answer

Stapedial

Answer

Corneal

Answer

Pupillary

Answer

Gag reflex

Question 6

Which of the following is not true regarding Vestibular neuroma

Accepted Answer

Normal Corneal reflex

Answer

Nystagmus

Answer

High frequency sensorineural deafness

Answer

Absence of caloric response

Question 7

True about acoustic neuroma:

Accepted Answer

Arises from vestibular nerve

Answer

Malignant tumour

Answer

Upper pole compresses IX,X,XI nerves

Answer

Lower pole compresses trigeminal cranial nerve

Question 8

Acoustic neuroma causes:

Accepted Answer

Retrocochlear deafness

Answer

Any of the above

Answer

Conductive deafness

Answer

Cochlear deafness

Question 9

All of the following are true about glomus-jugulare tumor except:

Accepted Answer

Most commonly affects male

Answer

Are paragangliomas

Answer

Arises from the adventitia of jugular bulb

Answer

Pulsatile tinnitus and conductive deafness seen

Question 10

If in a patient of acoustic neuroma, corneal reflex is absent it implies involvement of cranial nerve:

Accepted Answer

5th

Answer

None of the options

Answer

Both

Answer

7th

Neurotology — MCQs

Neurotology — MCQs

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