Diagnostic Investigations in ENT Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Diagnostic Investigations in ENT. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Diagnostic Investigations in ENT Indian Medical PG Question 1: To distinguish between cochlear and post-cochlear damage, which test is done?
- A. Auditory brainstem response (ABR) (Correct Answer)
- B. Impedance audiometry
- C. Pure tone audiometry
- D. Electrocochleography (ECochG)
Diagnostic Investigations in ENT Explanation: ***Auditory brainstem response (ABR)***
- This test evaluates the integrity of the **auditory pathway from the cochlea through the brainstem**, making it excellent for differentiating between cochlear (sensory) and post-cochlear (retrocochlear/neural) lesions.
- Abnormalities in wave latencies or interpeak intervals suggest **retrocochlear pathology** (e.g., acoustic neuroma), while normal ABR responses despite hearing loss point towards cochlear damage.
- ABR records **five characteristic waves (I-V)** representing neural transmission from the auditory nerve through the brainstem.
*Impedance audiometry*
- Primarily assesses the **middle ear function**, including the eardrum and ossicles, by measuring **tympanic membrane compliance** and **acoustic reflexes**.
- It does not directly evaluate the function of the **cochlea or the retrocochlear pathways**, making it unsuitable for this differentiation.
*Pure tone audiometry*
- Measures a person's **hearing sensitivity** at different frequencies and provides information on the **degree and type of hearing loss (conductive, sensorineural, or mixed)**.
- While it identifies sensorineural hearing loss, it cannot pinpoint whether the damage is **cochlear or retrocochlear** within the sensorineural category.
*Electrocochleography (ECochG)*
- Records **electrical potentials generated by the cochlea and auditory nerve** in response to sound, including **cochlear microphonics, summating potentials, and compound action potentials**.
- While it evaluates cochlear function and is useful in diagnosing **Meniere's disease** and **auditory neuropathy**, it does not adequately assess the **integrity of the brainstem auditory pathways** needed to differentiate retrocochlear lesions.
Diagnostic Investigations in ENT Indian Medical PG Question 2: Identify the marked structure in the given image.
- A. Electrode
- B. Coil (Correct Answer)
- C. Magnet
- D. Processor
Diagnostic Investigations in ENT Explanation: ***Coil***
- The marked structure appears to be a **cochlear implant's internal coil**, which is common in X-ray imaging of these devices.
- The **cochlear implant internal coil** is crucial for transmitting processed sound signals via electromagnetic induction to the electrode array within the cochlea.
*Electrode*
- An **electrode array** is typically a thin, flexible wire with multiple contacts inserted into the cochlea, which is not what the arrow is pointing to directly.
- While electrodes are part of a cochlear implant, the marked structure's shape and position are more consistent with the **internal coil** that connects to the electrode array.
*Magnet*
- A **magnet** is present in a cochlear implant system, typically in both the external processor and internal receiver, to hold these two components together through the skin.
- Magnets usually appear as dense, circular structures in X-rays, often seen more anteriorly or superiorly to the coil for external component alignment.
*Processor*
- The **processor** for a cochlear implant is an external device worn behind the ear, not an implanted component visible on an X-ray. It processes sound and sends it to the internal coil.
- The structures seen in the X-ray are **implanted components** of the cochlear implant, not the external sound processor.
Diagnostic Investigations in ENT Indian Medical PG Question 3: Which of the following is the best tuning fork to perform Rinne's and Weber's tests?
- A. 128 Hz
- B. 256 Hz
- C. 512 Hz (Correct Answer)
- D. 1024 Hz
Diagnostic Investigations in ENT Explanation: ***512 Hz***
- A **512 Hz tuning fork** is considered ideal for both Rinne's and Weber's tests because its frequency falls within the **speech frequency range**, which is clinically relevant for detecting hearing loss.
- This frequency also produces an optimal tone that is **sustained long enough** to perform the tests accurately, without being too low (which can cause vibratory sensation) or too high (which decays too quickly).
*128 Hz*
- Tuning forks with **lower frequencies** like 128 Hz are more likely to be perceived as a **vibration sensation** rather than pure sound, especially during bone conduction, which can lead to inaccurate test results.
- While useful for testing **vibratory sensation** in neurological exams, it is not preferred for distinguishing between air and bone conduction in hearing tests.
*256 Hz*
- Although it produces a clear tone, a **256 Hz tuning fork** can still introduce some degree of **vibratory sensation**, potentially confusing test interpretation, especially in bone conduction.
- The **512 Hz fork** offers a better balance between sound clarity and minimal vibratory sensation for hearing assessment.
*1024 Hz*
- A **1024 Hz tuning fork** produces a high-frequency tone that tends to **decay too quickly**, making it difficult to accurately compare air and bone conduction times, especially in the Weber test.
- While useful for testing higher frequencies, its **short sustain time** makes it less practical for the comparative nature of Rinne's and Weber's tests.
Diagnostic Investigations in ENT Indian Medical PG Question 4: Caloric test assesses the function of
- A. Anterior semicircular canal
- B. Superior semicircular canal
- C. Posterior semicircular canal
- D. Lateral semicircular canal (Correct Answer)
Diagnostic Investigations in ENT Explanation: ***Lateral semicircular canal***
- The **caloric test** specifically evaluates the function of the **lateral (horizontal) semicircular canal** and its associated neural pathways.
- Introducing warm or cold water into the ear canal creates convection currents in the endolymph of the lateral semicircular canal, stimulating or inhibiting the hair cells.
*Anterior semicircular canal*
- The caloric test primarily affects the horizontal canal due to its anatomical position; it does not directly assess the **anterior semicircular canal**.
- The anterior canal is mainly involved in sensing **rotational movements** of the head in the sagittal plane.
*Superior semicircular canal*
- The **superior semicircular canal** is another name for the anterior semicircular canal and is therefore not directly assessed by the caloric test.
- It detects angular accelerations, particularly when the head is tilted forward or backward.
*Posterior semicircular canal*
- The caloric test has minimal to no direct impact on the **posterior semicircular canal**.
- The posterior canal is involved in sensing rotational movements, particularly those in the coronal plane, like tilting the head to the shoulder.
Diagnostic Investigations in ENT Indian Medical PG Question 5: Following are the laboratory tests for the diagnosis of vestibular dysfunction except -
- A. Galvanic test
- B. Electronystagmography
- C. Gelle's test (Correct Answer)
- D. Optokinetic test
Diagnostic Investigations in ENT Explanation: ***Gelle's test***
- **Gelle's test** is used to evaluate the mobility of the **tympanic membrane** and the integrity of the **ossicular chain**, primarily in the diagnosis of **otosclerosis**.
- It does not directly assess the function of the **vestibular system** or its pathways.
*Galvanic test*
- The Galvanic test involves applying an electrical current to the mastoid process to stimulate the **vestibular nerve** directly.
- It assesses the function of the **semicircular canals** and their connections to the brainstem.
*Electronystagmography*
- **Electronystagmography (ENG)** records eye movements during various maneuvers to evaluate the function of the **vestibular-ocular reflex (VOR)**.
- It helps detect nystagmus and other eye movement abnormalities indicative of **vestibular dysfunction**.
*Optokinetic test*
- The **optokinetic test** assesses the ability of the eyes to follow moving targets, evaluating the **central vestibular pathways** and their interaction with the visual system.
- It can help differentiate between peripheral and central **vestibular disorders**.
Diagnostic Investigations in ENT Indian Medical PG Question 6: The investigation of choice for vestibular schwannoma is
- A. Gadolinium enhanced MRI (Correct Answer)
- B. PET scan
- C. SPECT
- D. Contrast enhanced CT scan
Diagnostic Investigations in ENT Explanation: ***Gadolinium enhanced MRI***
- **Gadolinium-enhanced MRI** is the gold standard due to its superior spatial resolution for soft tissues, allowing for clear visualization of the tumor within the **internal auditory canal** and **cerebellopontine angle**.
- It effectively detects even small **vestibular schwannomas**, which are typically missed by other imaging modalities.
*PET scan*
- **PET scans** are primarily used for assessing metabolic activity in tumors and are more relevant for distinguishing between benign and malignant lesions, or for staging cancer, rather than purely anatomical localization of a **vestibular schwannoma**.
- Its resolution is often insufficient to precisely delineate small lesions in the **internal auditory canal**.
*SPECT*
- **SPECT** uses gamma-ray emitting radiotracers and is more commonly employed in nuclear medicine for functional imaging of organs or to assess blood flow, particularly in cardiac or neurological conditions like epilepsy, rather than for detailed anatomical imaging of tumors such as **vestibular schwannomas**.
- Its spatial resolution is generally lower than MRI, making it less suitable for detecting small lesions in complex anatomical regions.
*Contrast enhanced CT scan*
- While a **contrast-enhanced CT scan** can show larger tumors and bony erosion, its soft tissue contrast is inferior to MRI, which means it may miss smaller **vestibular schwannomas**.
- It also exposes the patient to **ionizing radiation**, and its primary role in vestibular schwannoma detection is often limited to cases where MRI is contraindicated.
Diagnostic Investigations in ENT Indian Medical PG Question 7: A 72-year-old man presents to his primary care physician with progressively worsening hearing loss. He states that his trouble with hearing began approximately 7-8 years ago. He is able to hear when someone is speaking to him; however, he has difficulty with understanding what is being said, especially when there is background noise. In addition to his current symptoms, he reports a steady ringing in both ears, and at times experiences dizziness. Medical history is significant for three prior episodes of acute otitis media. Family history is notable for his father being diagnosed with cholesteatoma. His temperature is 98.6°F (37°C), blood pressure is 138/88 mmHg, pulse is 74/min, and respirations are 13/min. On physical exam, when a tuning fork is placed in the middle of the patient's forehead, sound is appreciated equally on both ears. When a tuning fork is placed by the external auditory canal and subsequently on the mastoid process, air conduction is greater than bone conduction. Which of the following is most likely the cause of this patient's symptoms?
- A. Stapedial abnormal bone growth
- B. Endolymphatic hydrops
- C. Cochlear hair cell degeneration (Correct Answer)
- D. Accumulation of desquamated keratin debris
Diagnostic Investigations in ENT Explanation: ***Cochlear hair cell degeneration***
- The patient's **progressive, bilateral hearing loss** over several years, difficulty understanding speech in noise, and **tinnitus** are classic symptoms of **presbycusis**, which results from age-related **degeneration of cochlear hair cells**.
- The **normal Weber test** (no lateralization) and **Rinne test** (air conduction > bone conduction) indicate a **sensorineural hearing loss**, consistent with cochlear pathology rather than conductive issues.
*Stapedial abnormal bone growth*
- This condition (**otosclerosis**) causes **conductive hearing loss** due to fixation of the stapes, which would present with an **abnormal Rinne test** (bone conduction > air conduction) in the affected ear.
- While it can cause progressive hearing loss and tinnitus, the normal Rinne test contradicts this diagnosis.
*Endolymphatic hydrops*
- This is the underlying pathology of **Ménière's disease**, which typically presents with episodic vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural fullness.
- The patient's dizziness is non-episodic, and the absence of fluctuating hearing loss and aural fullness makes Ménière's less likely.
*Accumulation of desquamated keratin debris*
- This describes a **cholesteatoma**, which typically causes **conductive hearing loss** and often presents with otorrhea, earache, and possibly vestibular symptoms.
- The normal Rinne test (indicating sensorineural loss) and lack of otorrhea or earache make cholesteatoma unlikely, despite a family history.
Diagnostic Investigations in ENT Indian Medical PG Question 8: In a child aged 3-12 years with an ear problem, which one of these situations merits urgent referral to hospital?
- A. Pus seen draining from the ear, and discharge reported for more than or equal to 14 days
- B. Pus seen draining from the ear, and discharge reported for less than 14 days
- C. Tender swelling behind the ear (Correct Answer)
- D. Pus seen draining from both ears, irrespective of duration
Diagnostic Investigations in ENT Explanation: ***Tender swelling behind the ear***
- A **tender swelling behind the ear**, particularly in a child with an ear problem, is a classic sign of **mastoiditis**, which is a serious complication requiring urgent medical attention due to the risk of intracranial spread.
- **Mastoiditis** often presents with fever, pain, and a prominent, pushed-out auricle.
*Pus seen draining from the ear, and discharge reported for more than or equal to 14 days*
- This suggests **chronic suppurative otitis media (CSOM)**, which typically requires a referral to ENT for assessment and management but is not usually an *urgent* referral unless there are signs of complications.
- While concerning, the chronicity itself doesn't immediately indicate an acute emergency in the absence of other symptoms like fever or severe pain.
*Pus seen draining from the ear, and discharge reported for less than 14 days*
- This indicates acute otitis media (AOM) with perforation, which is very common in children.
- It usually resolves with antibiotics and local care, and while a follow-up is important, it doesn't typically require urgent hospital referral.
*Pus seen draining from both ears, irrespective of duration*
- Bilateral ear discharge suggests bilateral acute or chronic otitis media, but does not inherently imply an acute emergency that requires urgent hospital referral.
- The key factor for urgency would be signs of complications, such as mastoiditis or intracranial involvement, rather than the bilaterality of discharge alone.
Diagnostic Investigations in ENT Indian Medical PG Question 9: Gelle's test is done in?
- A. Traumatic deafness
- B. Senile deafness
- C. Otosclerosis (Correct Answer)
- D. Serous otitis media
Diagnostic Investigations in ENT Explanation: ***Otosclerosis***
- **Gelle's test** is primarily used to diagnose **otosclerosis**, a condition causing **conductive hearing loss** due to abnormal bone growth in the middle ear.
- The test assesses changes in **bone conduction hearing** in response to alterations in external ear canal pressure, which is characteristic of a fixed stapes footplate in otosclerosis.
*Traumatic deafness*
- **Traumatic deafness** can result from direct injury to the ear, but **Gelle's test** is not a primary diagnostic tool for this type of hearing loss.
- Diagnosis typically involves evaluating the **nature and extent of the trauma** and other audiometric tests.
*Senile deafness*
- Also known as **presbycusis**, **senile deafness** is a **sensorineural hearing loss** associated with aging.
- **Gelle's test** assesses changes in bone conduction with pressure, making it less relevant for diagnosing age-related nerve damage.
*Serous otitis media*
- **Serous otitis media** involves fluid accumulation in the middle ear, leading to **conductive hearing loss**.
- While it causes conductive hearing loss, **Gelle's test** is not the definitive diagnostic test; **tympanometry** and **audiometry** are more commonly used.
Diagnostic Investigations in ENT Indian Medical PG Question 10: The following test is useful for diagnosis of all except:
- A. Ossicular discontinuity
- B. Otosclerosis
- C. Serous otitis media
- D. Postmeningitis deafness (Correct Answer)
Diagnostic Investigations in ENT Explanation: ***Postmeningitis deafness***
- The image illustrates a **tympanometer**, which primarily assesses the function of the **middle ear** and **eardrum mobility** within the context of air pressure changes.
- **Postmeningitis deafness** typically results from **sensorineural hearing loss** due to damage to the **cochlea** or **auditory nerve**, which is a condition of the inner ear and cannot be directly diagnosed by tympanometry.
*Ossicular discontinuity*
- This condition involves a break or separation in the **ossicular chain**, leading to excessive mobility of the tympanic membrane.
- Tympanometry in **ossicular discontinuity** typically shows a **Type Ad tympanogram**, characterized by abnormally high compliance due to the lack of resistance from the damaged ossicles.
*Otosclerosis*
- **Otosclerosis** involves abnormal bone growth around the **stapes** footplate, leading to its fixation and reduced mobility.
- Tympanometry in otosclerosis typically yields a **Type As tympanogram**, indicating abnormally low compliance or a shallow peak.
*Serous otitis media*
- Also known as **otitis media with effusion**, this condition involves the accumulation of fluid in the middle ear without signs of acute infection.
- Tympanometry in **serous otitis media** typically presents with a **Type B tympanogram**, characterized by a flat curve due to reduced or absent eardrum mobility caused by the fluid.
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