Facial Nerve Palsy — MCQs
Bilateral facial nerve palsy is seen in
All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
Herpes zoster in geniculate ganglion causes?
True about lower motor neuron palsy of VIIth nerve:
A 40-year-old man presents with sudden onset of unilateral facial paralysis. He is unable to close his eye or raise his eyebrow. What is the most likely diagnosis?
In Ramsay Hunt syndrome, all nerves are involved except
Which clinical sign can detect facial nerve palsy occurring due to the lesion at the outlet of stylomastoid foramen -
All are ophthalmological emergencies except -
Which of the following statements regarding traumatic facial nerve palsy is false?
A patient presents with facial nerve palsy and vertigo after mastoid surgery. The most likely site of injury is:
Facial Nerve Palsy Indian Medical PG Practice Questions and MCQs
Question 1: Bilateral facial nerve palsy is seen in
- A. Melkersen Rosenthal syndrome
- B. Ramsay Hunt syndrome
- C. Guillain Barre syndrome (Correct Answer)
- D. Herpes zoster
Explanation: Guillain Barre syndrome - Guillain-Barré syndrome (GBS) is an acute, rapidly progressive, acquired demyelinating polyneuropathy that can classically present with bilateral facial nerve palsy [1]. - This is due to the widespread nature of the demyelination affecting peripheral nerves, including the facial nerves. Melkersen Rosenthal syndrome - This syndrome is characterized by a triad of recurrent facial paralysis, persistent orofacial swelling (e.g., cheilitis granulomatosa), and a fissured tongue. - While it causes facial nerve palsy, it is typically unilateral and recurrent, though it can occasionally be bilateral. Ramsay Hunt syndrome - This syndrome is caused by the reactivation of the varicella-zoster virus in the geniculate ganglion, leading to herpes zoster oticus. - It presents with unilateral facial paralysis, often accompanied by painful vesicular rash in the external auditory canal or on the auricle, hearing loss, and vertigo [2]. Herpes zoster - Herpes zoster (shingles) is a viral infection caused by the reactivation of the varicella-zoster virus, primarily affecting dermatomes. - While it can cause facial palsy (if it affects the geniculate ganglion, leading to Ramsay Hunt Syndrome), it is generally unilateral and not typically associated with bilateral facial nerve palsy [2].
Question 2: All of the following conditions are immediate priorities in the WHO's "Vision -2020: The Right to sight" except:
- A. Cataract
- B. Epidemic conjunctivitis (Correct Answer)
- C. Onchocerciasis
- D. Trachoma
Explanation: ***Epidemic conjunctivitis*** - While **epidemic conjunctivitis** can cause significant discomfort and temporary vision impairment, it is generally **self-limiting** and rarely leads to permanent blindness. - It was not identified as one of the top five global causes of avoidable blindness targeted by the Vision 2020 initiative. *Cataract* - **Cataract** is the **leading cause of blindness** globally, accounting for approximately half of all cases. - It is a highly treatable condition through surgery, making it a critical priority for Vision 2020. *Onchocerciasis* - Also known as **river blindness**, onchocerciasis is a parasitic disease that causes severe visual impairment and blindness. - It is a significant public health problem in several regions, particularly in Africa, and was a key focus of Vision 2020 due to its widespread impact and the availability of preventive chemotherapy. *Trachoma* - **Trachoma** is the **leading infectious cause of blindness** worldwide, caused by *Chlamydia trachomatis*. - Given its preventable and treatable nature, and its prevalence in many impoverished areas, it was designated as one of the priority diseases under Vision 2020.
Question 3: Herpes zoster in geniculate ganglion causes?
- A. Melkersson-Rosenthal syndrome
- B. Ramsay Hunt syndrome (Correct Answer)
- C. Bell's palsy
- D. Ophthalmic zoster
Explanation: ***Ramsay Hunt syndrome*** - This syndrome is caused by the **reactivation of varicella-zoster virus (VZV)** within the **geniculate ganglion**, leading to inflammation of the facial nerve (cranial nerve VII). - Key features include **ipsilateral facial paralysis**, **ear pain**, and a **vesicular rash in the external auditory canal** or on the auricle. *Melkersson-Rosenthal syndrome* - This is a rare neurological disorder characterized by a triad of symptoms: **recurrent facial paralysis**, **persistent orofacial swelling**, and **fissured tongue**. - It is not directly related to viral infection or the geniculate ganglion. *Bell's palsy* - Bell's palsy is an **idiopathic facial paralysis** that results from inflammation of the facial nerve, but the exact cause is unknown and it does not involve a vesicular rash. - While it shares some symptoms with Ramsay Hunt syndrome, the **absence of vesicles** distinguishes it. *Ophthalmic zoster* - Ophthalmic zoster occurs when VZV reactivates in the **trigeminal ganglion** (cranial nerve V), specifically affecting the ophthalmic division. - It presents with a **vesicular rash on the forehead, eyelids, and nose** (Hutchinson's sign), and can lead to serious ocular complications, but does not involve the facial nerve directly.
Question 4: True about lower motor neuron palsy of VIIth nerve:
- A. Forehead muscles are affected unlike upper motor neuron lesions
- B. Melkersson's syndrome causes recurrent paralysis
- C. Eye protection is done
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - All statements regarding **lower motor neuron (LMN) palsy of the VIIth cranial nerve** (facial nerve) are accurate. - This type of injury affects the entire ipsilateral side of the face, including the forehead and eye, which require specific protective measures [1]. *Melkersson's syndrome causes recurrent paralysis* - **Melkersson-Rosenthal syndrome** is characterized by the triad of **facial nerve palsy** (often recurrent), **orofacial swelling**, and **fissured tongue**. - The facial palsy in this syndrome is typically a **lower motor neuron lesion**. *Forehead muscles are affected unlike upper motor neuron lesions* - In a **lower motor neuron lesion**, all muscles of the ipsilateral face, including the **frontalis muscle** (which controls the forehead), are affected due to damage to the facial nerve nucleus or its peripheral branches. - In contrast, **upper motor neuron lesions** spare the forehead muscles because the upper face receives bilateral innervation from the cerebral cortex [1]. *Eye protection is done* - Due to paralysis of the **orbicularis oculi muscle**, patients cannot fully close their eye (lagophthalmos), leading to exposure keratitis and dryness. - **Eye protection** with artificial tears, lubricating ointments, and eyelid taping is crucial to prevent corneal damage [1].
Question 5: A 40-year-old man presents with sudden onset of unilateral facial paralysis. He is unable to close his eye or raise his eyebrow. What is the most likely diagnosis?
- A. Myasthenia gravis
- B. Trigeminal neuralgia
- C. Bell's palsy (Correct Answer)
- D. Stroke
Explanation: ***Bell's palsy*** - **Bell's palsy** presents as an **idiopathic, sudden-onset, unilateral facial nerve paralysis** affecting both the upper and lower face (inability to close eye or raise eyebrow). - This condition is thought to be due to **inflammation or compression of the facial nerve (CN VII)**, leading to a complete hemifacial weakness or paralysis [2]. *Myasthenia gravis* - **Myasthenia gravis** is an **autoimmune disorder** primarily affecting the **neuromuscular junction**, causing fluctuating muscle weakness that worsens with activity and improves with rest. - While it can affect facial muscles, it typically presents with **ptosis**, **diplopia**, and generalized weakness, not an acute unilateral paralysis of the entire hemiface. *Trigeminal neuralgia* - **Trigeminal neuralgia** is characterized by **brief, severe, electric shock-like pains** in the distribution of the **trigeminal nerve (CN V)**, often triggered by touch or movement. - It does not cause muscle weakness or paralysis, but rather sensory symptoms and pain. *Stroke* - A **stroke** causing facial paralysis typically results in **sparing of the forehead** (the patient can still raise their eyebrow) because the upper facial muscles receive bilateral cortical innervation [1]. - While a stroke can cause sudden unilateral weakness, the inability to raise the eyebrow is a key differentiating feature making Bell's palsy more likely [2].
Question 6: In Ramsay Hunt syndrome, all nerves are involved except
- A. 7
- B. 5
- C. 9 (Correct Answer)
- D. 6
- E. 8
Explanation: Cranial nerve IX, the **glossopharyngeal nerve**, is typically *not involved* in the classic presentation of Ramsay Hunt syndrome, which primarily affects facial and auditory nerves. - Involvement of CN IX would present with symptoms like **dysphagia** or loss of taste on the posterior tongue, which are not characteristic features of the syndrome. Cranial nerve VII, the **facial nerve**, is the *primary nerve affected* in Ramsay Hunt syndrome, causing **facial paralysis** on the affected side [1]. - This paralysis results from reactivation of the **varicella-zoster virus** in the geniculate ganglion. Cranial nerve V, the **trigeminal nerve**, can occasionally be affected, leading to **facial pain** or numbness in the distribution of its sensory branches. - While not a primary feature, its involvement can contribute to the severity and discomfort experienced by patients. Cranial nerve VI, the **abducens nerve**, can be involved in Ramsay Hunt syndrome, leading to **diplopia** due to impairment of the **lateral rectus muscle**. - Its involvement is considered an *atypical presentation* but has been documented in severe cases. Cranial nerve VIII, the **vestibulocochlear nerve**, is frequently involved, causing **vertigo**, **nystagmus**, and **hearing loss** (sensorineural) on the affected side. - This involvement is due to the close proximity of the vestibulocochlear ganglion to the geniculate ganglion.
Question 7: Which clinical sign can detect facial nerve palsy occurring due to the lesion at the outlet of stylomastoid foramen -
- A. Deviation of tongue towards opposite side
- B. Loss of sensation over right cheek
- C. Loss of taste sensation in anterior 2/3 of tongue
- D. Deviation of angle of mouth towards opposite side (Correct Answer)
Explanation: ***Deviation of angle of mouth towards opposite side*** - A lesion of the facial nerve at the **stylomastoid foramen** specifically affects the motor innervation to the **muscles of facial expression**. [1] - This leads to **paralysis of facial expression muscles** on the ipsilateral side, causing the mouth to **deviate towards the unaffected side** due to unopposed muscle action. [1] *Deviation of tongue towards opposite side* - **Tongue deviation** is primarily indicative of a lesion in the **hypoglossal nerve (CN XII)**, which controls the intrinsic and extrinsic muscles of the tongue. - The facial nerve is not involved in **tongue movement**. *Loss of sensation over right cheek* - **Sensory innervation** to the face, including the cheek, is provided by the **trigeminal nerve (CN V)**, not the facial nerve. - The facial nerve is primarily a **motor nerve** for facial expression, although it carries some sensory fibers for taste and a small area of the ear. *Loss of taste sensation in anterior 2/3 of tongue* - **Taste sensation** from the **anterior two-thirds of the tongue** is carried by the **chorda tympani nerve**, which is a branch of the facial nerve. - However, the **chorda tympani branches off proximal to the stylomastoid foramen**, meaning a lesion at the foramen itself would not affect taste.
Question 8: All are ophthalmological emergencies except -
- A. Endophthalmitis
- B. CRVO (Correct Answer)
- C. Acute congestive glaucoma
- D. CRAO
Explanation: ***CRVO*** - Central Retinal Vein Occlusion (CRVO) is characterized by painless **vision loss** due to retinal hemorrhage and edema, but it is generally *not* considered an immediate, vision-threatening emergency in the same vein as the other options. - While it requires prompt evaluation and management to preserve vision, CRVO allows for a less urgent intervention compared to conditions that can lead to permanent vision loss within hours. *Endophthalmitis* - **Endophthalmitis** is a severe inflammation of the intraocular fluids and tissues, typically caused by infection, and can lead to rapid and irreversible vision loss if not treated urgently. - It presents with pain, redness, reduced vision, and hypopyon (pus in the anterior chamber), necessitating immediate antibiotic treatment and surgical intervention. *Acute congestive glaucoma* - **Acute congestive glaucoma** (acute angle-closure glaucoma) involves a sudden increase in intraocular pressure, causing severe pain, redness, corneal edema, and profound vision loss. - If left untreated, the high pressure can cause irreversible damage to the optic nerve within hours, making it a true ocular emergency. *CRAO* - **Central Retinal Artery Occlusion (CRAO)** is a sudden, painless loss of vision in one eye due to blockage of the central retinal artery, leading to retinal ischemia. - It is an ocular emergency because irreversible retinal damage and vision loss can occur within 90-120 minutes of the occlusion, requiring immediate intervention to restore blood flow.
Question 9: Which of the following statements regarding traumatic facial nerve palsy is false?
- A. Posttraumatic facial nerve palsy may be complete at the time of presentation
- B. Decompression of the canal can be useful treatment
- C. Usually occurs with longitudinal petrous temporal bone fracture (Correct Answer)
- D. Usually occurs with transverse petrous temporal bone fracture
Explanation: ***Usually occurs with longitudinal petrous temporal bone fracture*** ✓ FALSE - This is the correct answer - **Longitudinal temporal bone fractures** account for the majority (70-80%) of temporal bone fractures but are **less likely to cause severe facial nerve palsy** (10-20% incidence) compared to transverse fractures. - When facial nerve injury does occur with a longitudinal fracture, it typically involves the **tympanic segment** and can be caused by **edema or contusion**, often presenting with delayed or incomplete palsy rather than direct transection. *Usually occurs with transverse petrous temporal bone fracture* - **Transverse temporal bone fractures** are less common (20-30%) but are associated with a **higher incidence and severity of immediate facial nerve paralysis** (30-50% incidence) due to direct nerve transection or severe compression. - These fractures typically cross the **internal auditory canal** and otic capsule, often damaging the labyrinth and facial nerve directly. *Posttraumatic facial nerve palsy may be complete at the time of presentation* - **Complete facial nerve paralysis** can occur immediately after trauma, particularly with **transverse temporal bone fractures**, indicating severe injury such as nerve transection. - Early assessment of the degree of paralysis using the House-Brackmann grading system is crucial for determining prognosis and guiding management strategies. *Decompression of the canal can be useful treatment* - **Surgical decompression of the facial nerve canal** may be considered for patients with **immediate complete paralysis** or **progressive paralysis** following trauma, especially if imaging shows nerve entrapment or significant edema. - The decision for surgery is usually guided by **electrophysiological studies** (electroneuronography showing >90% degeneration) and high-resolution CT imaging to assess the extent of nerve damage and fracture pattern.
Question 10: A patient presents with facial nerve palsy and vertigo after mastoid surgery. The most likely site of injury is:
- A. Vertical segment (Correct Answer)
- B. Geniculate ganglion
- C. Tympanic segment
- D. Labyrinthine segment
Explanation: ***Vertical segment (Mastoid segment)*** - The **vertical (mastoid) segment** of the facial nerve descends through the mastoid bone from the second genu to the stylomastoid foramen. - This segment is **most vulnerable during mastoidectomy** due to its course through the surgical field, particularly in patients with dehiscent facial nerve canals or anatomical variations. - Injury manifests as **facial nerve palsy** (complete or partial facial weakness). - **Vertigo** occurs when surgical trauma extends to adjacent structures like the **semicircular canals** (especially the lateral/horizontal canal which lies close to the mastoid antrum) or causes thermal injury to the vestibular apparatus. - This combined presentation of facial palsy + vertigo points specifically to the vertical segment injury during mastoid surgery. *Labyrinthine segment* - The **labyrinthine segment** is the shortest and narrowest segment, running from the internal auditory canal to the geniculate ganglion. - It lies **deep within the petrous temporal bone**, far from the typical mastoid surgical field. - Injury here is rare during mastoidectomy unless there is extensive petrous bone drilling or complications. - Would cause facial palsy and potentially hearing loss, but is not the typical site of injury during mastoid surgery. *Geniculate ganglion* - The **geniculate ganglion** is located at the first genu where the facial nerve transitions from labyrinthine to tympanic segment. - It lies **medial and superior** to the middle ear cavity, protected by bone. - Injury would cause facial palsy, loss of taste (anterior 2/3 tongue via chorda tympani), hyperacusis (stapedius dysfunction), and decreased lacrimation. - **Less commonly injured** during routine mastoidectomy; vertigo is not a primary feature unless there is extension to the vestibular apparatus. *Tympanic segment* - The **tympanic (horizontal) segment** runs along the medial wall of the middle ear above the oval window. - While it can be exposed during mastoidectomy with extended approaches, it is **less frequently injured** than the vertical segment in standard mastoid surgery. - Injury causes facial palsy but **vertigo is less characteristic** unless the procedure directly involves the oval window or horizontal semicircular canal.
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