Diseases of the Larynx Practice Questions

Q: In the Nodal "N" staging of laryngeal carcinoma, extranodal invasion is indicated by which category?

N3B. **Explanation:** The staging of laryngeal carcinoma follows the **AJCC 8th Edition** TNM classification. The 8th edition introduced a significant change by incorporating **Extranodal Extension (ENE)** into the "N" staging, as it is a major prognostic indicator for poor outcomes. **1. Why N3b is correct:** According to the AJCC 8th Edition, the **N3** category is subdivided based on size and ENE: * **N3a:** Metastasis in a lymph node larger than 6 cm in greatest dimension, but **without** extranodal extension (ENE-). * **N3b:** Metastasis in any node(s) with **clinically overt extranodal extension (ENE+)**. This means if ENE is present, the size or number of nodes no longer dictates the stage; it automatically becomes N3b. **2. Why other options are incorrect:** * **N2c:** Represents bilateral or contralateral lymph node metastasis, none larger than 6 cm, and without ENE. * **N3a:** As mentioned, this is a large node (>6 cm) but specifically lacks extranodal invasion. * **N3c:** This category does not exist in the current AJCC TNM staging for laryngeal cancer. **High-Yield Clinical Pearls for NEET-PG:** * **ENE Definition:** Extension of tumor through the lymph node capsule into the surrounding connective tissue. * **Clinical ENE:** Suggested by skin involvement, fixation to adjacent structures (muscles/vessels), or nerve invasion. * **TNM 7th vs 8th:** In the 7th edition, N3 was simply any node >6 cm. The 8th edition added ENE to refine prognostic accuracy. * **Most common site:** The most common site for laryngeal cancer is the **Glottis**, but **Supraglottic** cancers have a higher rate of nodal metastasis due to rich lymphatic drainage.

Q: Topical mitomycin C is used in the treatment of which condition?

Tracheal stenosis. **Explanation:** **Correct Answer: B. Tracheal stenosis** **Mechanism and Rationale:** Mitomycin C (MMC) is an antineoplastic antibiotic derived from *Streptomyces caespitosus*. Its primary medical utility in ENT is its ability to **inhibit fibroblast proliferation** and protein synthesis. When applied topically to the site of a tracheal or subglottic stenosis (usually after endoscopic dilation or laser excision), it prevents the formation of excessive granulation tissue and collagen deposition. This reduces the rate of restenosis and maintains the patency of the airway. **Analysis of Incorrect Options:** * **A. Basal cell carcinoma:** While MMC is used topically in ophthalmology for ocular surface squamous neoplasia, the standard of care for BCC is surgical excision (Mohs surgery) or radiotherapy. * **C. Skull base osteomyelitis:** This is a severe infection (usually Pseudomonas in diabetics) requiring long-term systemic intravenous antibiotics and potentially surgical debridement, not topical antiproliferative agents. * **D. Angiofibroma:** Juvenile Nasopharyngeal Angiofibroma (JNA) is a benign but locally aggressive vascular tumor. The primary treatment is surgical excision (often preceded by embolization). MMC has no role in its management. **High-Yield Clinical Pearls for NEET-PG:** * **Concentration:** Typically used at a concentration of **0.4 mg/ml** applied for 2–5 minutes. * **Other ENT Uses:** MMC is also used topically in **Myringotomy** (to keep the perforation patent longer) and in **Dacryocystorhinostomy (DCR)** or sinus surgery to prevent ostial stenosis. * **Tracheal Stenosis Etiology:** The most common cause of acquired tracheal stenosis is prolonged endotracheal intubation (pressure necrosis from the cuff).

Q: Bilateral recurrent laryngeal nerve palsy is seen in which of the following conditions?

All of the above. **Explanation:** The **Recurrent Laryngeal Nerve (RLN)** is the primary motor nerve of the larynx, supplying all intrinsic muscles except the cricothyroid. Because of its long, vulnerable course—especially its proximity to the thyroid gland and the esophagus—it is susceptible to injury from both surgical trauma and malignant infiltration. **Why "All of the above" is correct:** * **Thyroidectomy:** This is the **most common surgical cause** of bilateral RLN palsy. During total thyroidectomy or subtotal thyroidectomy, both nerves can be inadvertently ligated, bruised, or transected due to their close anatomical relationship with the inferior thyroid artery and the Berry’s ligament. * **Carcinoma Thyroid:** Advanced thyroid malignancies (especially medullary or anaplastic types) can invade locally. If the tumor involves both tracheoesophageal grooves, it can result in bilateral nerve paralysis. * **Cancer of the Cervical Esophagus:** The RLNs ascend in the tracheoesophageal grooves. Malignant growths of the cervical esophagus can infiltrate these grooves bilaterally, leading to nerve compromise. **Clinical Pearls for NEET-PG:** 1. **Position of Cords:** In bilateral RLN palsy, both vocal cords typically assume a **median or paramedian position** because the cricothyroid muscle (supplied by the Superior Laryngeal Nerve) remains intact and adducts the cords. 2. **Clinical Presentation:** The hallmark is **stridor and respiratory distress**, while the voice may remain surprisingly good. This is a medical emergency often requiring a tracheostomy. 3. **Semon’s Law:** States that in progressive lesions, abductor fibers are injured before adductor fibers. 4. **Most common cause of Unilateral RLN palsy:** Historically, it was thyroid surgery; however, idiopathic causes and lung/mediastinal malignancies are also frequent.

Q: A 65-year-old man presented with vocal cord palsy. He has a history of pan chewing since childhood. On examination, the abducting function of his vocal cord is impaired. Which nerve is most likely affected?

Recurrent laryngeal nerve. ### Explanation The correct answer is **Recurrent Laryngeal Nerve (RLN)**. **1. Why the Recurrent Laryngeal Nerve is correct:** The intrinsic muscles of the larynx are responsible for the abduction and adduction of the vocal cords. All intrinsic muscles of the larynx—except for the cricothyroid—are supplied by the **Recurrent Laryngeal Nerve**. Specifically, the **Posterior Cricoarytenoid (PCA)** is the sole abductor of the vocal cords (often called the "safety muscle of the larynx"). Therefore, any impairment in the abducting function of the vocal cord directly indicates a lesion or palsy of the RLN. **2. Why the other options are incorrect:** * **External Laryngeal Nerve:** This nerve supplies only the **Cricothyroid muscle**, which acts as a tensor of the vocal cords. Damage to this nerve leads to a loss of pitch and a "husky" voice, but not a loss of abduction. * **Mandibular Nerve:** This is a branch of the Trigeminal nerve (CN V) and supplies the muscles of mastication and sensory innervation to the lower face. It has no role in vocal cord movement. * **Vagus Nerve:** While the RLN is a branch of the Vagus nerve (CN X), a high vagal lesion would typically present with additional symptoms like dysphagia (due to pharyngeal branch involvement) or palatal palsy. The specific loss of abduction is the hallmark of its distal branch, the RLN. **3. High-Yield Clinical Pearls for NEET-PG:** * **Posterior Cricoarytenoid (PCA):** The only **abductor** (Safety muscle). * **Lateral Cricoarytenoid (LCA):** The primary **adductor**. * **Semon’s Law:** In progressive lesions of the RLN, abductor fibers are more susceptible and are paralyzed first compared to adductor fibers. * **Left RLN** is more commonly involved in vocal cord palsy because of its longer intrathoracic course (looping around the arch of the aorta), making it vulnerable to mediastinal pathologies (e.g., lung cancer, mitral stenosis/Ortner’s syndrome).

Q: Which anatomical landmark is used to determine the level of tracheostomy?

Isthmus of the thyroid. **Explanation:** The **isthmus of the thyroid gland** is the primary anatomical landmark used to determine the level of a tracheostomy. In a standard elective tracheostomy, the isthmus typically overlies the second, third, and fourth tracheal rings. To access the trachea, the surgeon must either retract the isthmus superiorly/inferiorly or divide it between clamps to expose the underlying tracheal rings. * **Why Option B is correct:** The isthmus serves as the "gatekeeper" to the trachea. Its identification is crucial for surgical orientation. Once the isthmus is managed, the incision is usually made in the **2nd and 3rd or 3rd and 4th tracheal rings**. * **Why Option A is wrong:** The **Cricoid cartilage** is the landmark for a **Cricothyroidotomy** (emergency airway), not a tracheostomy. Performing a tracheostomy at or above the cricoid is contraindicated as it leads to subglottic stenosis. * **Why Options C & D are wrong:** While the 2nd and 3rd tracheal rings are the *site* where the tracheal window is created, they are not the *landmark* used to navigate the procedure. The thyroid isthmus must be identified first to safely reach these rings. **High-Yield Clinical Pearls for NEET-PG:** 1. **Level of Tracheostomy:** High (1st ring - avoided), Mid (2nd, 3rd, 4th rings - **Preferred**), Low (below 4th ring - avoided due to risk of injury to the innominate artery). 2. **Emergency Airway:** Cricothyroidotomy is the procedure of choice for immediate airway obstruction. 3. **Most common complication (Immediate):** Hemorrhage (from thyroid vessels or anterior jugular veins). 4. **Most common late complication:** Tracheal stenosis.

Q: Laryngeal edema is a life-threatening situation seen in association with which of the following conditions?

Ludwig's angina. ### Explanation **Ludwig’s Angina** is a rapidly spreading, life-threatening cellulitis of the submandibular space (including sublingual and submaxillary spaces), usually of dental origin. The correct answer is **C** because the infection causes massive swelling of the floor of the mouth, pushing the tongue superiorly and posteriorly. This displacement, combined with the spread of edema to the epiglottis and supraglottic structures via the parapharyngeal space, leads to acute airway obstruction and **laryngeal edema**. **Analysis of Incorrect Options:** * **A. Cavernous Sinus Thrombosis:** This is a late complication of infections in the "danger area of the face." It presents with proptosis, chemosis, and cranial nerve palsies (III, IV, V1, V2, VI), but does not typically cause laryngeal edema. * **B. Infection of Pharyngeal Tonsils:** Acute tonsillitis or adenoiditis primarily causes odynophagia or nasal obstruction. While a peritonsillar abscess (Quinsy) can cause some trismus, it rarely leads to generalized laryngeal edema unless it spreads to the deep neck spaces. * **D. Cellulitis:** General skin cellulitis (unless specifically involving the submandibular space as in Ludwig's) does not involve the deep neck structures required to trigger laryngeal edema. **Clinical Pearls for NEET-PG:** * **Source:** 70-80% of Ludwig’s Angina cases arise from the **2nd and 3rd lower molars**. * **Clinical Sign:** "Woody" or "brawny" edema of the neck; the patient often presents with a "bull-neck" appearance and drooling. * **Management:** The priority is **airway maintenance** (often requiring tracheostomy if intubation fails). Antibiotics and surgical drainage are secondary. * **Key Space:** It is a **submandibular space** infection; it does not involve the subdiaphragmatic or retropharyngeal spaces primarily.

Q: Cadaveric position of vocal cords is seen in which condition?

Bilateral recurrent and superior laryngeal nerve palsy. ### Explanation The position of the vocal cords is determined by the balance of intrinsic laryngeal muscles. The **cadaveric position** (neutral position) occurs when the vocal cords are approximately 3.5 mm from the midline, representing a state of total denervation. **1. Why Option A is Correct:** The vocal cords are controlled by two main nerves: the **Recurrent Laryngeal Nerve (RLN)**, which supplies all intrinsic muscles except the cricothyroid, and the **Superior Laryngeal Nerve (SLN)**, specifically its external branch, which supplies the cricothyroid (the primary tensor). * In **Bilateral RLN palsy**, the cords usually lie in the paramedian position because the cricothyroid muscles (supplied by the intact SLN) continue to adduct the cords. * When **both the RLN and SLN are paralyzed bilaterally**, the cricothyroid also loses function. This results in a total loss of muscle tone, causing the cords to fall into the **cadaveric position**. **2. Why Other Options are Incorrect:** * **Option B (Bilateral RLN palsy):** The cords are in the **paramedian position**. This is a surgical emergency as it causes severe airway obstruction (stridor), though the voice may remain relatively good. * **Option C & D (SLN palsy):** Isolated SLN palsy primarily affects the tension of the cords. It results in a wavy or "scalloped" appearance of the cord margin and a loss of high-pitched notes, but not a cadaveric position. **3. High-Yield Clinical Pearls for NEET-PG:** * **Median Position (0 mm):** Seen in phonation. * **Paramedian Position (1.5 mm):** Seen in isolated RLN palsy. * **Cadaveric Position (3.5 mm):** Seen in combined RLN + SLN palsy. * **Full Abduction (7 mm):** Seen during deep inspiration. * **Semon’s Law:** States that in progressive nerve lesions, the abductor fibers (posterior cricoarytenoid) are more susceptible and paralyzed earlier than adductor fibers.

Question 1

In the Nodal "N" staging of laryngeal carcinoma, extranodal invasion is indicated by which category?

Accepted Answer

N3B

Answer

N2C

Answer

N3A

Answer

N3C

Question 2

Topical mitomycin C is used in the treatment of which condition?

Accepted Answer

Tracheal stenosis

Answer

Basal cell carcinoma

Answer

Skull base osteomyelitis

Answer

Angiofibroma

Question 3

Bilateral recurrent laryngeal nerve palsy is seen in which of the following conditions?

Accepted Answer

All of the above

Answer

Thyroidectomy

Answer

Carcinoma thyroid

Answer

Cancer of the cervical esophagus

Question 4

What is the most common site for performing a tracheostomy?

Accepted Answer

Retro thyroid region

Answer

Superior thyroid region

Answer

Infra thyroid region

Answer

Lateral thyroid region

Question 5

A 65-year-old man presented with vocal cord palsy. He has a history of pan chewing since childhood. On examination, the abducting function of his vocal cord is impaired. Which nerve is most likely affected?

Accepted Answer

Recurrent laryngeal nerve

Answer

External laryngeal nerve

Answer

Mandibular nerve

Answer

Vagus nerve

Question 6

An end tracheostomy is performed in patients undergoing which of the following procedures?

Accepted Answer

Laryngectomy

Answer

Laryngofissure surgery

Answer

Oropharyngeal tumor resection

Answer

Surgical correction of obstructive sleep apnea with stridor

Question 7

Which anatomical landmark is used to determine the level of tracheostomy?

Accepted Answer

Isthmus of the thyroid

Answer

Cricoid cartilage

Answer

Second tracheal ring

Answer

Third tracheal ring

Question 8

Laryngeal edema is a life-threatening situation seen in association with which of the following conditions?

Accepted Answer

Ludwig's angina

Answer

Cavernous sinus thrombosis

Answer

Infection of pharyngeal tonsils

Answer

Cellulitis

Question 9

Cadaveric position of vocal cords is seen in which condition?

Accepted Answer

Bilateral recurrent and superior laryngeal nerve palsy

Answer

Bilateral recurrent laryngeal nerve palsy

Answer

Unilateral superior laryngeal nerve palsy

Answer

Bilateral superior laryngeal nerve palsy

Question 10

Which of the following are indications for tracheostomy?

Accepted Answer

Flail chest, Head injury, Tetanus, Foreign body

Answer

Head injury, Tetanus, Cardiac tamponade, Foreign body

Answer

Flail chest, Head injury, Tetanus, Cardiac tamponade

Answer

Flail chest, Head injury, Cardiac tamponade, Foreign body

Diseases of the Larynx — MCQs

Diseases of the Larynx — MCQs

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