Perilymphatic Fistula — MCQs
Hennebert's sign is a false positive fistula test when there is no evidence of middle ear disease causing a fistula of the horizontal semicircular canal. It is seen in?
Mainstay of treatment of glue ear -
A patient presents with vertigo, tinnitus, and head tilt. He underwent myringoplasty for the safe type of chronic suppurative otitis media (CSOM) 6 months back. What is your diagnosis?
In a patient with chronic suppurative otitis media, which structure is most commonly involved in labyrinthine fistula?
Most common cause of sensorineural hearing loss (SNHL)
A patient with cholesteatoma has lateral semicircular canal fistula. The most specific sign is:
What is the diagnosis shown in the following image?
Which of the following associations is true regarding facial nerve palsy in temporal bone fractures?
All of the following are true about transverse fractures of the temporal bone EXCEPT:
A patient with a sinus infection develops chemosis, bilateral proptosis, and fever. What is the most likely diagnosis?
Perilymphatic Fistula Indian Medical PG Practice Questions and MCQs
Question 1: Hennebert's sign is a false positive fistula test when there is no evidence of middle ear disease causing a fistula of the horizontal semicircular canal. It is seen in?
- A. Congenital syphilis
- B. Cholesteatoma
- C. Stapedectomy
- D. Meniere’s disease (Correct Answer)
Explanation: ***Meniere's disease*** - **Hennebert's sign** is a *false-positive fistula test* resulting from a hypermobile footplate or saccule, or a fibrous band between the stapes footplate and the utricle due to otolithic *hydrops*. - It indicates that changes in external ear canal pressure cause **nystagmus** and **vertigo** due to inner ear fluid displacement, even without a true fistula. - This is the **most common** cause of Hennebert's sign in clinical practice. *Congenital syphilis* - Congenital syphilis can also present with Hennebert's sign as a false-positive fistula test due to inner ear involvement. - However, the question context specifies Hennebert's sign in the absence of middle ear disease, making Meniere's disease the more typical answer. - Other features include **sensorineural hearing loss**, **vestibular dysfunction**, **interstitial keratitis**, and **Hutchinson's teeth**. *Cholesteatoma* - A cholesteatoma often erodes bone, leading to a **true fistula** in the horizontal semicircular canal, especially its lateral aspect. - This would result in a *true positive fistula test* rather than a false positive associated with Hennebert's sign. *Stapedectomy* - A stapedectomy is a surgical procedure to treat otosclerosis, involving the removal of the stapes and insertion of a prosthesis. - While it can lead to complications such as perilymph fistula, it is not directly associated with Hennebert's sign as a *pre-existing condition* causing a false-positive fistula test in the absence of middle ear disease.
Question 2: Mainstay of treatment of glue ear -
- A. Temporal bone resection
- B. Tonsillectomy & adenoidectomy
- C. Radical Mastoidectomy
- D. Myringotomy + aeration to middle ear (Correct Answer)
Explanation: ***Myringotomy + aeration to middle ear*** - **Myringotomy** involves creating a small incision in the eardrum to drain fluid, and inserting a **grommet (ventilation tube)** to aerate the middle ear, which is the primary treatment for persistent glue ear (otitis media with effusion). - This procedure aims to restore ventilation to the middle ear, allowing trapped fluid to drain and preventing recurrent fluid accumulation, which improves hearing. *Temporal bone resection* - This is a major surgical procedure involving the removal of part of the temporal bone, typically reserved for extensive **malignant tumors** or severe infections, and is not indicated for glue ear. - It carries significant risks and is disproportionate to the treatment of a benign condition like glue ear. *Tonsillectomy & adenoidectomy* - While **adenoidectomy** can sometimes be performed in conjunction with grommet insertion if enlarged adenoids contribute to eustachian tube dysfunction, it is not the **primary treatment** for glue ear itself. - **Tonsillectomy** is generally performed for recurrent tonsillitis and has no direct role in treating glue ear. *Radical Mastoidectomy* - This is a highly invasive surgical procedure involving the removal of the mastoid air cells and part of the external auditory canal, typically performed for severe **cholesteatoma** or chronic mastoiditis. - It is an extensive and risky operation that is not appropriate for the management of glue ear, which is a much milder condition.
Question 3: A patient presents with vertigo, tinnitus, and head tilt. He underwent myringoplasty for the safe type of chronic suppurative otitis media (CSOM) 6 months back. What is your diagnosis?
- A. Paget disease
- B. Labyrinthitis
- C. Vestibular schwannoma
- D. Perilymphatic fistula (Correct Answer)
Explanation: ***Perilymphatic fistula*** - The combination of **vertigo**, **tinnitus**, and **head tilt** occurring after a **myringoplasty**, even for a safe type of CSOM, suggests a perilymphatic fistula. - Myringoplasty can occasionally involve trauma to the **oval or round window**, leading to a direct communication between the inner ear (perilymph) and the middle ear, causing these symptoms. *Paget disease* - This is a **bone remodeling disorder** that primarily affects the skull, pelvis, and long bones, leading to bone pain and deformities. - While it can cause hearing loss (due to otosclerosis) and a sense of imbalance, it does not typically present with the acute onset of **vertigo** and **tinnitus** following ear surgery. *Labyrinthitis* - **Labyrinthitis** is an inflammation of the inner ear, typically caused by a viral infection, leading to sudden, severe **vertigo**, **nausea**, and often **hearing loss** or **tinnitus**. - While the symptoms of vertigo and tinnitus are present, the history of recent myringoplasty makes a **structural compromise** like a perilymphatic fistula a more specific diagnosis than generalized inflammation. *Vestibular schwannoma* - Also known as an acoustic neuroma, this is a **benign tumor** on the eighth cranial nerve, causing **gradual unilateral hearing loss**, **tinnitus**, and **imbalance**, but rarely sudden, intense vertigo unless very large. - The presentation with a history of myringoplasty and acute symptoms makes a **spontaneous structural defect** more likely than a slowly growing tumor.
Question 4: In a patient with chronic suppurative otitis media, which structure is most commonly involved in labyrinthine fistula?
- A. Superior semicircular canal
- B. Posterior semicircular canal
- C. Utricle
- D. Lateral semicircular canal (Correct Answer)
Explanation: ***Lateral semicircular canal*** - The **lateral semicircular canal** is the most commonly involved structure in labyrinthine fistula due to its anatomical prominence in the **epitympanum** and its thinner bony wall compared to other labyrinths, making it susceptible to erosion from cholesteatoma. - **Cholesteatoma**, a common complication of chronic suppurative otitis media, erodes bone due to its enzymatic activity, frequently affecting this canal as it lies in the direct path of disease extension. *Superior semicircular canal* - While possible, involvement of the **superior semicircular canal** is much less common than the lateral canal due to its deeper and more protected anatomical position. - Erosion leading to fistula in this canal would typically indicate very extensive and aggressive disease. *Posterior semicircular canal* - The **posterior semicircular canal** is also less frequently affected in labyrinthine fistula compared to the lateral canal. - Its deep anatomical location and often thicker surrounding bone provide more protection against erosion. *Utricle* - The **utricle** is part of the vestibule and is surrounded by a substantial bony labyrinth, making direct fistulization from otitis media or cholesteatoma relatively rare. - Fistulae usually occur in the semicircular canals where the bony walls are thinner and more exposed to disease processes.
Question 5: Most common cause of sensorineural hearing loss (SNHL)
- A. Labyrinthitis
- B. Meniere's disease
- C. Presbycusis (Correct Answer)
- D. Vestibular Schwannoma
Explanation: ***Presbycusis*** - **Presbycusis**, or age-related hearing loss, is the most common cause of **sensorineural hearing loss (SNHL)**, affecting a significant portion of the elderly population. - It typically results from **degenerative changes** in the inner ear, specifically the hair cells and nerve fibers, leading to a gradual, symmetrical, high-frequency SNHL. *Labyrinthitis* - **Labyrinthitis** is an inflammation of the inner ear that can cause sudden SNHL, often accompanied by **vertigo** and **tinnitus**. - While it causes SNHL, it is an acute condition and not the most common overall cause, especially when considering the prevalence of age-related hearing loss. *Meniere's disease* - **Meniere's disease** is characterized by recurrent episodes of **vertigo, fluctuating low-frequency SNHL, tinnitus**, and aural fullness. - It is a specific condition causing SNHL, but its prevalence is much lower than presbycusis, making it a less common overall cause. *Vestibular Schwannoma* - A **vestibular schwannoma** (acoustic neuroma) is a benign tumor that arises from the Schwann cells of the **vestibulocochlear nerve**. - It can cause **progressive unilateral SNHL**, tinnitus, and balance issues, but it is a relatively rare condition compared to presbycusis.
Question 6: A patient with cholesteatoma has lateral semicircular canal fistula. The most specific sign is:
- A. Head thrust test
- B. Fistula test (Correct Answer)
- C. Hennebert's sign
- D. Dix-Hallpike test
Explanation: ***Fistula test*** - The **fistula test** (Positive pressure test or Hennebert's test) directly assesses for a communication between the middle ear and the labyrinth by applying positive or negative pressure to the external auditory canal. - A positive result, indicated by **nystagmus** or **vertigo** induced by pressure changes, is the **most specific sign** for a **labyrinthine fistula** in the context of **cholesteatoma**. - The lateral semicircular canal is the most commonly affected site in cholesteatoma-related fistulae. *Hennebert's sign* - **Hennebert's sign** refers to **nystagmus** or **vertigo** induced by pressure changes in the external auditory canal **in the absence of an actual fistula**. - It represents a **false positive fistula test** and is classically associated with **congenital syphilis**, **Meniere's disease**, or other conditions causing increased labyrinthine membrane mobility. - In this case with a **confirmed fistula**, the positive pressure test would be called a **positive fistula test**, not Hennebert's sign. *Head thrust test* - The **head thrust test** evaluates the function of the **vestibulo-ocular reflex (VOR)** and is used to detect **peripheral vestibular hypofunction**. - While cholesteatoma can affect vestibular function, this test is **not specific** for identifying a **labyrinthine fistula**. *Dix-Hallpike test* - The **Dix-Hallpike test** is used to diagnose **Benign Paroxysmal Positional Vertigo (BPPV)** by identifying nystagmus and vertigo triggered by specific head positions. - This test detects **otoconia displacement** in the semicircular canals and is **not relevant** for identifying a **labyrinthine fistula**.
Question 7: What is the diagnosis shown in the following image?
- A. Hyperinsulinism
- B. Conductive hearing defect
- C. Perichondritis (Correct Answer)
- D. Mucopolysaccharidosis
Explanation: ***Perichondritis*** - The image exhibits signs of **inflammation and swelling** of the external ear, consistent with **perichondritis**, an infection of the tissue surrounding the ear cartilage. - This condition can lead to **redness**, **pain**, and fluid collection (abscess formation) that distorts the ear's normal architecture. - Typically spares the **lobule** (which lacks cartilage) and presents as an **acute inflammatory condition**. *Hyperinsulinism* - **Hyperinsulinism** is a metabolic disorder characterized by excessive insulin secretion and has no relationship to external ear pathology. - This is not an appropriate option for an acute inflammatory ear condition shown in clinical images. *Conductive hearing defect* - A **conductive hearing defect** is a functional diagnosis, not a structural/pathological diagnosis visible on examination. - It refers to problems in sound transmission through the **external or middle ear**, but is not itself visible as inflammation or swelling. - The image shows an **acute inflammatory condition**, not a hearing disorder. *Mucopolysaccharidosis* - **Mucopolysaccharidoses** are lysosomal storage disorders that can cause progressive dysmorphic facial features, including ear structure changes. - However, these present with **chronic, diffuse structural changes** rather than acute inflammation and swelling. - The acute inflammatory presentation in the image is inconsistent with this genetic storage disorder.
Question 8: Which of the following associations is true regarding facial nerve palsy in temporal bone fractures?
- A. Common with longitudinal fractures
- B. Common with transverse fractures (Correct Answer)
- C. Always associated with CSF otorrhea
- D. Facial nerve injury is always complete
Explanation: **Explanation:** Temporal bone fractures are classically categorized based on their orientation relative to the long axis of the petrous part of the temporal bone. Understanding the anatomical path of the facial nerve is key to predicting injury patterns. * **Why Option B is Correct:** **Transverse fractures** (occurring perpendicular to the petrous ridge) are far more likely to involve the facial nerve. Although they account for only 20% of all temporal bone fractures, they result in facial nerve palsy in approximately **50% of cases**. This is because the fracture line often crosses the internal auditory canal or the fallopian canal directly. * **Why Option A is Incorrect:** **Longitudinal fractures** are the most common type (80%), but they involve the facial nerve in only about **15-20% of cases**. The injury here is usually due to edema or compression rather than direct transection. * **Why Option C is Incorrect:** While CSF otorrhea can occur in longitudinal fractures (due to tympanic membrane rupture), transverse fractures more commonly present with **CSF rhinorrhea** (as the CSF leaks through the Eustachian tube) or a hemotympanum with an intact drum. It is not an "always" association. * **Why Option D is Incorrect:** Facial nerve injury can be **incomplete (paresis)** or **complete (paralysis)**. In longitudinal fractures, the palsy is often delayed and incomplete, whereas in transverse fractures, it is more likely to be immediate and complete. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common site of injury:** The **Geniculate Ganglion** (Perigeniculate area) is the most frequent site of facial nerve injury in temporal bone trauma. 2. **Management:** Immediate-onset complete paralysis usually indicates nerve transection (requires surgical exploration); delayed-onset palsy suggests edema (managed conservatively with steroids). 3. **Hearing Loss:** Longitudinal fractures are associated with **conductive hearing loss** (ossicular disruption), while transverse fractures cause **sensorineural hearing loss** (labyrinthine involvement).
Question 9: All of the following are true about transverse fractures of the temporal bone EXCEPT:
- A. Facial nerve is commonly involved
- B. Sensorineural deafness can occur
- C. Conductive deafness can occur (Correct Answer)
- D. These fractures are less common
Explanation: Temporal bone fractures are traditionally classified into **Longitudinal** and **Transverse** based on their relationship to the long axis of the petrous pyramid. ### Why Option C is the Correct Answer (The "EXCEPT") Transverse fractures run perpendicular to the petrous ridge, typically crossing the internal auditory canal or the bony labyrinth (cochlea/vestibule). Because the fracture line directly destroys the inner ear structures or the vestibulocochlear nerve, it results in **Sensorineural Hearing Loss (SNHL)**. Conductive hearing loss is characteristic of *longitudinal* fractures, where the tympanic membrane or ossicular chain is disrupted, but the inner ear is spared. ### Analysis of Incorrect Options * **A. Facial nerve is commonly involved:** True. The facial nerve is injured in approximately **50%** of transverse fractures (compared to only 20% in longitudinal). The injury is often a complete transection. * **B. Sensorineural deafness can occur:** True. As the fracture line traverses the otic capsule, it causes permanent, often profound, SNHL and severe vertigo/nystagmus. * **D. These fractures are less common:** True. Transverse fractures account for only **20%** of temporal bone fractures, usually resulting from severe frontal or occipital blows. Longitudinal fractures are more common (80%). ### High-Yield Clinical Pearls for NEET-PG | Feature | Longitudinal Fracture (80%) | Transverse Fracture (20%) | | :--- | :--- | :--- | | **Mechanism** | Lateral blow (Temporal) | Frontal/Occipital blow | | **Hearing Loss** | **Conductive** (Common) | **Sensorineural** (Common) | | **Facial Nerve** | 20% (Delayed/Neuropraxia) | **50%** (Immediate/Transection) | | **Bleeding** | Bleeding from Ear (Tear in TM) | **Hemotympanum** (Intact TM) | | **CSF Leak** | CSF Otorrhea | CSF Rhinorrhea (via Eustachian tube) |
Question 10: A patient with a sinus infection develops chemosis, bilateral proptosis, and fever. What is the most likely diagnosis?
- A. Lateral sinus thrombosis
- B. Frontal lobe abscess
- C. Cavernous sinus thrombosis (Correct Answer)
- D. Meningitis
Explanation: **Explanation:** The clinical triad of **chemosis (conjunctival edema), bilateral proptosis, and fever** following a sinus infection is the classic presentation of **Cavernous Sinus Thrombosis (CST)**. **1. Why Cavernous Sinus Thrombosis is correct:** The cavernous sinuses are paired venous structures located on either side of the sella turcica. They receive venous drainage from the face (via the ophthalmic veins) and the paranasal sinuses (ethmoid and sphenoid). An infection in these areas can lead to septic thrombosis. * **Proptosis and Chemosis:** Occur due to impaired venous drainage from the orbit. * **Bilateral Involvement:** This is the hallmark of CST. Because the two cavernous sinuses communicate via the intercavernous sinuses, an infection starting on one side rapidly spreads to the other. **2. Why other options are incorrect:** * **Lateral Sinus Thrombosis:** Usually a complication of chronic suppurative otitis media (CSOM). It presents with "Griesinger's sign" (edema over the mastoid) and a "picket-fence" fever, but not proptosis or chemosis. * **Frontal Lobe Abscess:** Presents with features of raised intracranial pressure (headache, vomiting, papilledema) and altered mental status, but lacks the specific orbital signs seen here. * **Meningitis:** Presents with fever, neck stiffness, and photophobia. While it can coexist with CST, it does not explain the mechanical orbital findings (proptosis). **Clinical Pearls for NEET-PG:** * **Nerves involved:** Cranial nerves III, IV, V1, V2, and VI pass through the cavernous sinus. **CN VI (Abducens)** is usually the first to be affected (lateral rectus palsy). * **Danger area of the face:** Infections here (e.g., furuncles) can lead to CST due to the **valveless** nature of the facial and ophthalmic veins. * **Treatment:** High-dose intravenous antibiotics and management of the primary source (sinus drainage).
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