Diseases of the Ear Practice Questions

Q: What is true regarding the organ of Corti?

All of the above.. 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.

Q: What is the commonest cause of Eustachian tube diseases?

Adenoids. **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).

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

Furunculosis. **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).

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

Nasopharyngeal carcinoma. **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.

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

All of the above.. **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).

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

Diplacusis. **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.

Q: 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?

Pseudomonas aeruginosa. **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).

Q: Cholesteatoma is commonly caused by:

Attico-antral perforation. **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).

Q: Gradenigo's syndrome consists of the following except?

Convulsions. **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).

Question 1

What is true regarding the organ of Corti?

Accepted Answer

All of the above.

Answer

The organ of Corti is contained within the scala media.

Answer

Endolymph is secreted by cells of the stria vascularis.

Answer

The whole organ of Corti rests on the basilar membrane.

Question 2

What is the commonest cause of Eustachian tube diseases?

Accepted Answer

Adenoids

Answer

Sinusitis

Answer

Otitis media

Answer

Pharyngitis

Question 3

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

Accepted Answer

Furunculosis

Answer

Oral cavity tumors

Answer

Temporomandibular joint problems

Answer

Teething

Question 4

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

Accepted Answer

Nasopharyngeal carcinoma

Answer

Chronic suppurative otitis media (CSOM)

Answer

Mastoiditis

Answer

Foreign body of the external ear

Question 5

Perforation of the tympanic membrane with destruction of the tympanic annulus is called?

Accepted Answer

Marginal

Answer

Attic

Answer

Subtotal

Answer

Total

Question 6

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

Accepted Answer

All of the above.

Answer

It is also called idiopathic cystic chondromalacia.

Answer

It presents as a painless, spontaneous, dome-shaped cystic swelling on the anterior surface of the auricle.

Answer

It is more common on the right side compared to the left.

Question 7

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

Accepted Answer

Diplacusis

Answer

Hyperacusis

Answer

Hypoacusis

Answer

Paracusis Willisii

Question 8

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?

Accepted Answer

Pseudomonas aeruginosa

Answer

Hemophilus influenzae

Answer

Klebsiella pneumoniae

Answer

Mucor sp.

Question 9

Cholesteatoma is commonly caused by:

Accepted Answer

Attico-antral perforation

Answer

Tubotympanic disease

Answer

Central perforation of tympanic membrane

Answer

Meniere's disease

Question 10

Gradenigo's syndrome consists of the following except?

Accepted Answer

Convulsions

Answer

Retro-orbital pain

Answer

Persistent ear discharge

Answer

External rectus palsy

Diseases of the Ear — MCQs

Diseases of the Ear — MCQs

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