Diseases of the Ear — MCQs

Diseases of the Ear Indian Medical PG Practice Questions and MCQs

Question 21: What is true regarding the organ of Corti?

A. The organ of Corti is contained within the scala media.
B. Endolymph is secreted by cells of the stria vascularis.
C. The whole organ of Corti rests on the basilar membrane.
D. All of the above. (Correct Answer)

Explanation: The **Organ of Corti** is the peripheral receptor organ for hearing, located within the cochlea of the inner ear. This question tests fundamental anatomical and physiological knowledge of the auditory system. ### **Detailed Explanation** 1. **Option A (Scala Media):** The cochlea is divided into three compartments: scala vestibuli, scala tympani, and **scala media** (cochlear duct). The organ of Corti is specifically housed within the scala media, which is filled with endolymph. 2. **Option B (Stria Vascularis):** The stria vascularis is a specialized vascularized epithelium located on the lateral wall of the scala media. Its primary function is the **secretion of endolymph** and the maintenance of its unique high-potassium, low-sodium ionic composition (creating the endocochlear potential). 3. **Option C (Basilar Membrane):** The organ of Corti is a cellular structure that sits entirely upon the **basilar membrane**, which separates the scala media from the scala tympani. Sound waves cause this membrane to vibrate, leading to the shearing of hair cell cilia against the tectorial membrane. Since all statements are anatomically and physiologically accurate, **Option D** is the correct answer. ### **High-Yield Clinical Pearls for NEET-PG** * **Endolymph vs. Perilymph:** Endolymph (high $K^+$) is found in the scala media; Perilymph (high $Na^+$, resembles CSF) is found in the scala vestibuli and tympani. * **Hair Cells:** There are **three rows of Outer Hair Cells** (OHC) and **one row of Inner Hair Cells** (IHC). IHCs are primarily responsible for sending auditory signals to the brain (95% of afferent innervation). * **Otoacoustic Emissions (OAE):** These are generated by the electromotility of the **Outer Hair Cells**. * **Tunnel of Corti:** Contains a special fluid called **"Cortilymph,"** which is chemically similar to perilymph (high $Na^+$) despite being located within the scala media.

Question 22: What is the commonest cause of Eustachian tube diseases?

A. Adenoids (Correct Answer)
B. Sinusitis
C. Otitis media
D. Pharyngitis

Explanation: **Explanation:** The **Eustachian tube (ET)** serves three primary functions: ventilation, protection, and drainage of the middle ear. In the pediatric population, the ET is shorter, wider, and more horizontal, making it highly susceptible to dysfunction. **Why Adenoids are the correct answer:** Adenoid hypertrophy is the **most common cause** of Eustachian tube dysfunction. It causes obstruction through two mechanisms: 1. **Mechanical Obstruction:** Enlarged adenoid tissue directly blocks the pharyngeal opening of the ET in the nasopharynx. 2. **Infective Source:** Adenoids act as a reservoir for pathogenic bacteria (forming a biofilm), leading to ascending infections and inflammatory edema of the ET lining (salpingitis). This is the leading precursor to Otitis Media with Effusion (OME). **Analysis of Incorrect Options:** * **B. Sinusitis:** While chronic sinusitis can cause secondary inflammation of the nasopharynx, it is less frequently the primary anatomical cause compared to adenoids. * **C. Otitis Media:** This is generally a **consequence** of ET disease, not the primary cause. ET dysfunction leads to negative middle ear pressure, resulting in Otitis Media. * **D. Pharyngitis:** General pharyngeal infections rarely cause chronic ET disease unless the infection specifically involves the nasopharynx (nasopharyngitis). **High-Yield Clinical Pearls for NEET-PG:** * **Gelle’s Test:** Used to check ET patency and ossicular chain mobility. * **Toynbee Maneuver:** Swallowing with the nose pinched; it is a more physiological way to test ET function than the Valsalva maneuver. * **Unilateral Serous Otitis Media in an adult:** Always rule out **Nasopharyngeal Carcinoma (NPC)** obstructing the ET (Fossa of Rosenmüller). * **Patulous ET:** Often seen after rapid weight loss; the patient complains of **autophony** (hearing their own voice).

Question 23: Referred pain in the ear can be caused by all of the following EXCEPT:

A. Furunculosis (Correct Answer)
B. Oral cavity tumors
C. Temporomandibular joint problems
D. Teething

Explanation: **Explanation:** The ear has a complex sensory nerve supply involving the **Trigeminal (V3)**, **Facial (VII)**, **Glossopharyngeal (IX)**, **Vagus (X)**, and **Greater Auricular (C2, C3)** nerves. **Referred otalgia** occurs when a disease process in a distant site shares a common neural pathway with the ear. **Why Furunculosis is the correct answer:** Furunculosis is a localized infection of the hair follicle in the outer cartilaginous part of the external auditory canal (usually caused by *Staphylococcus aureus*). Because the pathology is located **within the ear itself**, the pain is classified as **Primary Otalgia**, not referred pain. **Analysis of Incorrect Options (Causes of Referred Otalgia):** * **Oral cavity tumors:** Pain is referred via the **Lingual nerve (branch of V3)** or the **Glossopharyngeal nerve (IX)**. * **Temporomandibular joint (TMJ) problems:** The TMJ is supplied by the **Auriculotemporal nerve (branch of V3)**, which also supplies the external ear and tympanic membrane. This is a very common cause of referred earache. * **Teething:** Dental issues, including teething or impacted molars, refer pain to the ear via the **Alveolar nerves (branches of V3)**. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply Summary:** * **V3 (Auriculotemporal):** TMJ, teeth, anterior pinna. * **IX (Jacobson’s nerve):** Oropharynx, tonsils, base of tongue (Common after tonsillectomy). * **X (Arnold’s nerve):** Laryngopharynx, esophagus, vagal stimulation can cause a cough reflex during ear cleaning. * **Rule of Thumb:** In an elderly patient with a normal-looking ear complaining of severe earache, always rule out a malignancy in the upper aerodigestive tract (referred via IX or X).

Question 24: What is the cause of unilateral secretory otitis media in an adult?

A. Chronic suppurative otitis media (CSOM)
B. Nasopharyngeal carcinoma (Correct Answer)
C. Mastoiditis
D. Foreign body of the external ear

Explanation: **Explanation:** The presence of **unilateral secretory otitis media (SOM)** in an adult is a classic clinical "red flag" that must be considered **Nasopharyngeal Carcinoma (NPC)** until proven otherwise. **1. Why Nasopharyngeal Carcinoma is correct:** The underlying mechanism is **Eustachian tube dysfunction**. NPC typically arises from the **Fossa of Rosenmüller**, which is located adjacent to the pharyngeal opening of the Eustachian tube. As the tumor grows, it mechanically obstructs the tube, preventing middle ear ventilation. This leads to negative pressure and the subsequent accumulation of sterile fluid (effusion) in the middle ear. In adults, while SOM is often preceded by an upper respiratory infection, a persistent unilateral presentation requires a mandatory endoscopic examination of the nasopharynx. **2. Why other options are incorrect:** * **CSOM (A):** This involves a permanent perforation of the tympanic membrane with active or inactive infection; it does not present as an intact drum with fluid (secretory). * **Mastoiditis (C):** This is a complication of acute suppurative otitis media (ASOM) characterized by retroauricular pain, fever, and bone destruction, rather than painless fluid accumulation. * **Foreign body (D):** This affects the external auditory canal and may cause conductive hearing loss or discharge, but it does not cause fluid collection behind an intact tympanic membrane. **Clinical Pearls for NEET-PG:** * **Trotter’s Triad (for NPC):** 1. Conductive hearing loss (due to SOM), 2. Ipsilateral facial/temporoparietal pain (Trigeminal nerve involvement), 3. Palatal paralysis (Vagus nerve involvement). * **Most common symptom of NPC:** Cervical lymphadenopathy (often the upper deep cervical/jugulodigastric nodes). * **Investigation of choice:** Nasopharyngoscopy and biopsy; MRI is preferred for assessing local extent.

Question 25: Perforation of the tympanic membrane with destruction of the tympanic annulus is called?

A. Attic
B. Marginal (Correct Answer)
C. Subtotal
D. Total

Explanation: ### Explanation The classification of tympanic membrane (TM) perforations is based on their location and whether they involve the **tympanic annulus** (the thickened peripheral rim of the TM that fits into the tympanic sulcus). **1. Why "Marginal" is Correct:** A **marginal perforation** is defined as a perforation that reaches the periphery of the tympanic membrane, resulting in the **destruction of the tympanic annulus**. Clinically, this is highly significant because the absence of the fibrous annulus allows squamous epithelium from the external auditory canal to migrate into the middle ear cleft, leading to the formation of **cholesteatoma**. This is why marginal perforations are considered "unsafe" or "dangerous" types of Chronic Suppurative Otitis Media (CSOM). **2. Analysis of Incorrect Options:** * **Attic:** This perforation occurs in the *pars flaccida* (Shrapnell’s membrane) above the lateral process of the malleus. While also "unsafe" and associated with cholesteatoma, it specifically involves the attic region rather than the destruction of the annulus in the *pars tensa*. * **Subtotal:** This is a large perforation of the *pars tensa* where the **annulus remains intact**. A rim of the tympanic membrane is preserved circumferentially. It is considered a "safe" (tubotympanic) type. * **Total:** In a total perforation, the entire TM is absent, but the term specifically implies the loss of the membrane itself; the clinical hallmark of "marginal" is the specific involvement/destruction of the bony rim (annulus). **3. High-Yield Clinical Pearls for NEET-PG:** * **Central Perforation:** Any perforation where there is a rim of TM present all around (annulus is intact). Associated with **Safe/Tubotympanic CSOM**. * **Marginal/Attic Perforation:** Associated with **Unsafe/Atticoantral CSOM** and bone-eroding processes. * **Most common site for Attic Cholesteatoma:** Prussak’s space. * **Management:** Marginal perforations usually require surgery (Mastoidectomy with Tympanoplasty) due to the risk of cholesteatoma and intracranial complications.

Question 26: Which of the following statements regarding a pseudocyst of the pinna is true?

A. It is also called idiopathic cystic chondromalacia.
B. It presents as a painless, spontaneous, dome-shaped cystic swelling on the anterior surface of the auricle.
C. It is more common on the right side compared to the left.
D. All of the above. (Correct Answer)

Explanation: **Explanation:** **Pseudocyst of the Pinna** is a condition characterized by an intracartilaginous collection of fluid within the auricle, lacking an epithelial lining (hence the term "pseudocyst"). 1. **Why Option A is correct:** It is also known as **idiopathic cystic chondromalacia**. The pathogenesis involves the release of lysosomal enzymes that cause the degradation of auricular cartilage, leading to the formation of a cystic space. 2. **Why Option B is correct:** The classic presentation is a **painless, non-inflammatory, dome-shaped swelling**. It typically occurs on the **anterior surface** of the pinna, specifically within the scaphoid or triangular fossa. It often appears spontaneously or following minor repeated trauma. 3. **Why Option C is correct:** Epidemiological studies and clinical observations indicate a higher prevalence in males, with a peculiar predilection for the **right side** over the left, though the exact reason for this laterality remains idiopathic. Since all individual statements are factually accurate, **Option D (All of the above)** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Site:** Most common in the **scaphoid fossa**. * **Fluid Characteristics:** The aspirated fluid is typically **straw-colored** (serous) and albumin-rich. * **Treatment:** Simple aspiration often leads to recurrence. The treatment of choice is **aspiration followed by pressure dressing** (using buttons or corrugated rubber) or **deroofing** of the cyst wall to prevent fluid re-accumulation and maintain the contour of the pinna. * **Differential Diagnosis:** Must be distinguished from a hematoma auris (which follows significant trauma and is usually painful).

Question 27: What type of hearing defect is characteristic of Meniere's disease?

A. Hyperacusis
B. Hypoacusis
C. Diplacusis (Correct Answer)
D. Paracusis Willisii

Explanation: **Explanation:** **Meniere’s Disease** (Endolymphatic Hydrops) is characterized by a classic tetrad: episodic vertigo, fluctuating sensorineural hearing loss (SNHL), tinnitus, and aural fullness. **Why Diplacusis is correct:** Diplacusis (specifically *Diplacusis Binauralis*) is a hallmark of Meniere’s disease. Due to the distension of the cochlear duct (hydrops), the basilar membrane's tuning mechanism is altered. This causes the same sound frequency to be perceived at a different pitch in the affected ear compared to the normal ear. This "double hearing" is a highly characteristic finding during the active phases of the disease. **Analysis of Incorrect Options:** * **Hyperacusis (A):** An abnormal sensitivity to loud sounds. While seen in conditions like Bell’s Palsy (due to stapedius paralysis) or Tullio’s phenomenon, it is not the defining hearing defect of Meniere’s. * **Hypoacusis (B):** A general term for hearing loss. While Meniere’s causes SNHL, "Diplacusis" is the more specific and characteristic qualitative defect tested in exams. * **Paracusis Willisii (D):** This is a classic feature of **Otosclerosis**, where a patient hears better in noisy environments. **High-Yield Clinical Pearls for NEET-PG:** * **Hearing Loss Pattern:** Early Meniere’s shows **low-frequency SNHL** (rising audiogram). In late stages, it becomes flat or involves all frequencies. * **Recruitment Phenomenon:** Present in Meniere’s (indicates a cochlear lesion). The ear is more sensitive to small increases in intensity. * **Lermoyez Syndrome:** A variant where hearing improves during a vertigo attack ("the reverse Meniere’s"). * **Glycerol Test:** Used for diagnosis; it acts as an osmotic diuretic to temporarily reduce hydrops and improve hearing.

Question 28: A 73-year-old woman with a history of diabetes presents with left ear pain and drainage of pus from the ear canal. She has a swelling and tenderness over the left mastoid bone. Which of the following microorganisms is the MOST likely causative agent?

A. Hemophilus influenzae
B. Klebsiella pneumoniae
C. Mucor sp.
D. Pseudomonas aeruginosa (Correct Answer)

Explanation: **Explanation:** The clinical presentation of an elderly diabetic patient with severe ear pain (otalgia), purulent discharge, and mastoid tenderness strongly suggests **Malignant Otitis Externa (MOE)**, also known as Necrotizing Otitis Externa. **1. Why Pseudomonas aeruginosa is correct:** * **Pseudomonas aeruginosa** is the causative organism in more than 95% of cases of Malignant Otitis Externa. * It is an opportunistic gram-negative aerobe that thrives in the microenvironment of the external auditory canal. In immunocompromised individuals (like diabetics), it invades the soft tissues, cartilage, and eventually the temporal bone (osteomyelitis), leading to the characteristic severe pain and potential cranial nerve palsies. **2. Why the other options are incorrect:** * **Hemophilus influenzae:** Typically associated with Acute Otitis Media (AOM) in children, not invasive external ear infections in elderly diabetics. * **Klebsiella pneumoniae:** While it can cause various infections, it is a rare cause of MOE compared to Pseudomonas. * **Mucor sp.:** While diabetics are prone to Mucormycosis, it typically presents as Rhinocerebral Mucormycosis (involving the sinuses and orbit) rather than primary otitis externa. **Clinical Pearls for NEET-PG:** * **Pathognomonic Sign:** Presence of **granulation tissue** at the junction of the cartilaginous and bony part of the external auditory canal. * **Diagnosis:** **Technetium-99m scan** is used for initial diagnosis (detects osteoblastic activity); **Gallium-67 scan** is used to monitor treatment response (detects active infection). * **Complication:** The most common cranial nerve involved is the **Facial nerve (VII)** at the stylomastoid foramen. * **Treatment:** Long-term intravenous antipseudomonal antibiotics (e.g., Ciprofloxacin, Ceftazidime).

Question 29: Cholesteatoma is commonly caused by:

A. Attico-antral perforation (Correct Answer)
B. Tubotympanic disease
C. Central perforation of tympanic membrane
D. Meniere's disease

Explanation: **Explanation:** **1. Why Attico-antral perforation is correct:** Cholesteatoma is a hallmark of **Attico-antral type** of Chronic Suppurative Otitis Media (CSOM), also known as "unsafe" or "bone-eroding" ear disease. It involves the presence of keratinizing squamous epithelium in the middle ear cleft. This occurs most commonly via **marginal perforations** in the pars flaccida (attic) or the posterosuperior part of the pars tensa. These perforations allow the migration of squamous epithelium from the external auditory canal into the middle ear, leading to bone destruction and potential intracranial complications. **2. Why the other options are incorrect:** * **Tubotympanic disease:** This is the "safe" type of CSOM. It involves the anteroinferior part of the middle ear cleft and is characterized by a central perforation. It rarely, if ever, leads to cholesteatoma. * **Central perforation:** This is a feature of Tubotympanic disease. By definition, a central perforation is surrounded by a remnant of the tympanic membrane, which usually prevents the inward migration of squamous epithelium. * **Meniere's disease:** This is an inner ear disorder characterized by endolymphatic hydrops. It presents with a triad of vertigo, tinnitus, and sensorineural hearing loss, and has no pathological link to cholesteatoma. **Clinical Pearls for NEET-PG:** * **Pathogenesis Theories:** The most accepted theories for cholesteatoma include Wittmaack’s (Retraction pocket), Habermann’s (Epithelial migration), and Sade’s (Metaplasia). * **Hallmark Sign:** A "pearly white" mass seen behind the tympanic membrane or through a perforation. * **Bone Destruction:** Cholesteatoma causes bone erosion primarily due to the release of **osteoclasts** and enzymes like **Acid Phosphatase** and **Collagenase**. * **Treatment:** The definitive treatment for cholesteatoma is surgical (Mastoidectomy).

Question 30: Gradenigo's syndrome consists of the following except?

A. Retro-orbital pain
B. Persistent ear discharge
C. External rectus palsy
D. Convulsions (Correct Answer)

Explanation: **Explanation:** **Gradenigo’s Syndrome** is a classic clinical triad resulting from the spread of infection from the middle ear to the **petrous apex** (Petrositis). It is typically a complication of Chronic Suppurative Otitis Media (CSOM) or acute otitis media. **Why Convulsions is the correct answer:** Convulsions are not a feature of Gradenigo’s syndrome. Seizures usually indicate a more diffuse intracranial involvement, such as brain abscess, meningitis, or cortical venous sinus thrombosis. While petrositis is an intracranial complication, the syndrome itself is defined by localized pressure and inflammation at the petrous apex affecting specific cranial nerves. **Analysis of the Triad (Incorrect Options):** 1. **Retro-orbital pain (Option A):** This is caused by irritation of the **Trigeminal nerve (CN V)**, specifically the Gasserian ganglion, which lies in Meckel’s cave near the petrous apex. 2. **Persistent ear discharge (Option B):** Chronic or profuse otorrhea is a hallmark of the underlying middle ear infection and petrositis. 3. **External rectus palsy (Option C):** This is caused by involvement of the **Abducens nerve (CN VI)** as it passes through **Dorello’s canal**, located between the petrous tip and the sphenoid bone. This results in diplopia (double vision) on lateral gaze. **High-Yield Clinical Pearls for NEET-PG:** * **The Triad:** Otorrhea + Trigeminal neuralgia (Retro-orbital pain) + Abducens palsy. * **Anatomy:** Dorello’s canal is the most vulnerable site for CN VI in petrositis. * **Investigation of Choice:** **MRI** is superior to CT for visualizing bone marrow edema and abscess formation in the petrous apex. * **Treatment:** Aggressive intravenous antibiotics and surgical drainage (e.g., cortical or radical mastoidectomy with petrous apicectomy).

Practice by Chapter

Otitis Externa

Practice Questions

Acute Otitis Media

Practice Questions

Chronic Otitis Media

Practice Questions

Complications of Otitis Media

Practice Questions

Otosclerosis

Practice Questions

Presbycusis

Practice Questions

Sudden Sensorineural Hearing Loss

Practice Questions

Noise-Induced Hearing Loss

Practice Questions

Ménière's Disease

Practice Questions

Benign Paroxysmal Positional Vertigo

Practice Questions

Vestibular Neuritis

Practice Questions

Tumors of the Ear and Temporal Bone

Practice Questions

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