Diseases of the Larynx Practice Questions

Q: Which laser is used in laryngeal work?

CO2. **Explanation:** The **CO2 (Carbon Dioxide) laser** is the gold standard and most commonly used laser in laryngeal surgery. Its wavelength (10,600 nm) is highly absorbed by water, which constitutes the majority of soft tissue. This results in **excellent precision, minimal peripheral thermal damage (0.1 mm), and superior hemostasis** for small vessels. In laryngeal work, it is used for procedures like cordectomy, papilloma excision, and treating subglottic stenosis because it allows for "what you see is what you get" surgical accuracy, preserving the delicate vocal cord architecture. **Analysis of Incorrect Options:** * **Argon Laser:** Primarily used in otology (e.g., stapedotomy) and ophthalmology. It is absorbed by pigment (hemoglobin/melanin) rather than water, making it less ideal for general laryngeal tissue ablation. * **Nd:YAG Laser:** It has deep tissue penetration (up to 4-5 mm), which causes significant collateral thermal damage. While used for debulking large obstructing tracheobronchial tumors, it lacks the precision required for delicate laryngeal surgery. * **Holmium Laser:** Mainly used in urology (lithotripsy) and orthopedic surgery. It is rarely used in the larynx due to its pulsed nature and less predictable tissue interaction compared to CO2. **High-Yield Clinical Pearls for NEET-PG:** * **KTP (Potassium Titanyl Phosphate) Laser:** Known as the "vascular laser," it is excellent for angiolytic work (e.g., vocal cord varices or papillomas) as it is absorbed by hemoglobin. * **Safety Protocol:** When using CO2 lasers in the airway, **Laser-safe endotracheal tubes** (e.g., Mallinckrodt or Medtronic) must be used, and the cuff should be filled with **saline dyed with methylene blue** to detect accidental perforation immediately. * **Mode of Delivery:** CO2 lasers are typically delivered via a micromanipulator attached to an operating microscope.

Q: Reinke's space is seen in which of the following anatomical locations?

Vocal cords. **Explanation:** **Reinke’s space** is a potential subepithelial space located in the **vocal cords** (specifically the true vocal folds). It is situated between the overlying non-keratinizing squamous epithelium and the underlying vocal ligament. 1. **Why Vocal Cords are correct:** Reinke’s space contains loose areolar tissue and lacks lymphatic drainage. This anatomical peculiarity is why fluid accumulation occurs easily here, leading to **Reinke’s Edema**. This space is bounded superiorly and inferiorly by the line of arcuate and anteriorly by the anterior commissure. 2. **Why other options are incorrect:** * **Subglottis:** This region starts below the vocal folds. It is characterized by respiratory epithelium and does not contain the specific loose connective tissue layer of Reinke. * **Epiglottis:** The epiglottis consists of elastic cartilage covered by a mucous membrane; it does not possess the specialized layered architecture of the true vocal folds. * **Pharynx:** The pharyngeal walls consist of mucosa, submucosa, and muscle layers, lacking the distinct "space" required for vocal fold vibration. **Clinical Pearls for NEET-PG:** * **Reinke’s Edema:** Characteristically seen in **chronic smokers** and those with **vocal abuse**. It presents with a low-pitched, gravelly voice. * **Lymphatics:** Reinke’s space has **no lymphatics**, which is why early glottic (vocal cord) cancers have an excellent prognosis as they do not spread to lymph nodes early. * **Histology:** The vocal fold has five layers. Reinke’s space corresponds to the **superficial layer of the lamina propria**.

Q: Cadeveric position of vocal cords after thyroidectomy is typically due to which of the following?

Bilateral recurrent laryngeal nerve paralysis.. **Explanation:** The position of the vocal cords is determined by the balance of intrinsic laryngeal muscles. In **Bilateral Recurrent Laryngeal Nerve (RLN) paralysis**, all intrinsic muscles of the larynx are paralyzed except for the cricothyroid (supplied by the external laryngeal nerve). The cricothyroid acts as a tensor and slight adductor. When both RLNs are severed (often during extensive thyroid surgery), the cords lose their motor supply and assume the **cadaveric position**—a neutral, mid-abducted position (approx. 3.5mm from the midline) where they are neither fully open nor closed. **Analysis of Options:** * **Option A (Unilateral RLN paralysis):** The affected cord typically assumes a **paramedian position** (1.5mm from midline) because the intact cricothyroid muscle on the same side adducts it slightly. The patient presents with hoarseness but a safe airway. * **Option C & D (External Laryngeal Nerve paralysis):** This nerve supplies the cricothyroid muscle. Paralysis leads to a loss of tension in the vocal cords, resulting in a **wavy/zigzag appearance** and inability to produce high-pitched sounds, but does not result in a cadaveric position. **NEET-PG High-Yield Pearls:** 1. **Semon’s Law:** States that in progressive RLN lesions, abductor fibers (posterior cricoarytenoid) are more vulnerable and paralyzed before adductor fibers. 2. **Wagner and Grossman Hypothesis:** Explains that if the Superior Laryngeal Nerve is intact, the cricothyroid muscle keeps the paralyzed cord in a paramedian position; if both SLN and RLN are gone, the cord moves to the cadaveric position. 3. **Clinical Emergency:** Bilateral RLN injury is a surgical emergency because the cords may eventually fall into a paramedian position, causing acute airway obstruction (stridor) requiring tracheostomy.

Q: A one-day-old neonate presents with a weak cry since birth and biphasic stridor, suggestive of incomplete canalisation. What is the most common site of this defect?

Glottic. ### Explanation The clinical presentation of a neonate with a **weak cry** and **biphasic stridor** since birth, specifically mentioning **incomplete canalisation**, points towards a **Laryngeal Web**. **1. Why Glottic is Correct:** Laryngeal webs result from the failure of the larynx to recanalize during the 10th week of intrauterine life. The **glottis (vocal cords)** is the most common site for this defect, accounting for approximately **75% of cases**. Because the web involves the vocal cords, it interferes with phonation (leading to a weak or muffled cry) and narrows the airway (causing stridor). **2. Analysis of Incorrect Options:** * **Supraglottic:** While congenital anomalies like laryngomalacia occur here, webs are rare in this region. Supraglottic lesions typically present with inspiratory stridor and a normal cry. * **Subglottic:** This is the second most common site for congenital narrowing (e.g., Subglottic Stenosis), but it is not the primary site for defects of "incomplete canalisation" (webs). Subglottic lesions usually present with a normal cry but significant biphasic stridor. * **Hypopharynx:** This area is part of the pharynx, not the larynx. Obstructions here usually present with feeding difficulties or muffled voice (hot potato voice) rather than true laryngeal stridor. **3. Clinical Pearls for NEET-PG:** * **Most common congenital anomaly of larynx:** Laryngomalacia (presents with inspiratory stridor). * **Most common site of Laryngeal Web:** Glottis (specifically the anterior commissure). * **Triad of Laryngeal Web:** Weak cry/hoarseness, croup-like cough, and varying degrees of respiratory obstruction (stridor). * **Association:** Large glottic webs may be associated with **Shprintzen syndrome (22q11.2 deletion)**. * **Management:** Small webs may require no treatment; thick webs require endoscopic laser excision or placement of a Silastic keel.

Q: What is the most widely used treatment for recurrent respiratory papillomatosis?

CO2 laser ablation. **Explanation:** **Recurrent Respiratory Papillomatosis (RRP)** is a condition caused by Human Papillomavirus (HPV types 6 and 11), characterized by benign wart-like growths in the airway. The primary goal of treatment is to maintain a patent airway and improve voice quality while minimizing scarring. **Why CO2 Laser Ablation is correct:** The **CO2 laser** is considered the gold standard and most widely used treatment. Its wavelength is highly absorbed by water, allowing for precise, bloodless excision with minimal collateral thermal damage. This precision is vital in the larynx to prevent complications like anterior glottic webbing or permanent vocal cord scarring. **Analysis of Incorrect Options:** * **Diathermy excision:** This method involves significant thermal spread, which leads to excessive scarring and stenosis of the delicate laryngeal tissues. It is rarely used today. * **Excision with microdebrider:** While the microdebrider is a popular alternative (often preferred by some surgeons for faster removal and less thermal risk), the **CO2 laser remains the most "widely used" and classically cited** treatment in standard textbooks for NEET-PG. * **Wait for spontaneous resolution:** RRP is aggressive and can cause life-threatening airway obstruction. While juvenile-onset RRP may regress after puberty, active management is mandatory to prevent asphyxia. **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** HPV 6 (most common) and HPV 11 (more aggressive). * **Most common site:** True vocal cords (squamous epithelium). * **Triad of symptoms:** Hoarseness, stridor, and respiratory distress. * **Adjuvant therapy:** Cidofovir (antiviral) is the most common adjuvant used for severe, rapidly recurring cases. * **Tracheostomy:** Should be avoided if possible, as it can lead to "stomal seeding" and distal spread of the disease into the lungs.

Q: Laryngeal web most commonly involves which region?

Glottis. **Explanation:** **Laryngeal webs** are congenital or acquired membranes that span the laryngeal lumen. The correct answer is **Glottis** because approximately **75% of all laryngeal webs occur at the glottic level**, specifically involving the anterior commissure. 1. **Why Glottis is Correct:** Congenital laryngeal webs result from the failure of the laryngeal lumen to recanalize during the 10th week of gestation. Since recanalization starts posteriorly and moves anteriorly, the anterior glottis is the most common site for residual tissue. Acquired webs also most commonly affect the glottis following trauma (e.g., prolonged intubation or aggressive bilateral vocal cord surgery). 2. **Why other options are incorrect:** * **Supraglottis:** While webs can occur here, they are rare. Supraglottic pathology is more commonly associated with laryngomalacia or epiglottitis. * **Subglottis:** Subglottic involvement is less common than glottic. However, if a glottic web is thick, it may have subglottic extension (often seen in Shamblin’s Type III or IV). Isolated subglottic webs are rare compared to subglottic stenosis. * **Both Supraglottis and Glottis:** This is an uncommon distribution; most webs are localized to the glottis and may extend inferiorly rather than superiorly. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Anterior Glottis (Anterior Commissure). * **Clinical Triad:** Weak/hoarse cry (most common symptom), inspiratory stridor, and varying degrees of airway obstruction. * **Association:** Congenital glottic webs are strongly associated with **22q11.2 deletion (DiGeorge Syndrome)**. Always screen for cardiac defects if a web is found. * **Management:** Thin webs can be managed with endoscopic laser excision; thick webs may require an open procedure with the placement of a **Silastic Keel** to prevent re-adhesion of the vocal folds.

Q: Injury to the superior laryngeal nerve causes which of the following?

Loss of timbre of voice. The **Superior Laryngeal Nerve (SLN)** divides into two branches: the internal laryngeal nerve (sensory) and the **external laryngeal nerve (motor)**. The external branch supplies the **cricothyroid muscle**, which is the only intrinsic muscle of the larynx located outside the laryngeal framework. ### Why "Loss of timbre of voice" is correct: The cricothyroid muscle acts as a **tensor of the vocal cords**. It tilts the thyroid cartilage forward, lengthening and tightening the cords to increase the pitch of the voice. Injury to the SLN leads to paralysis of the cricothyroid, resulting in a loss of tension. This manifests clinically as: * **Loss of timbre (quality)** and range of voice. * Inability to produce high-pitched sounds (common in singers). * Easy vocal fatigue. ### Why other options are incorrect: * **A & B: Hoarseness and Paralysis of vocal cords:** These are characteristic of **Recurrent Laryngeal Nerve (RLN)** injury. The RLN supplies all other intrinsic muscles of the larynx and is responsible for vocal cord abduction/adduction. SLN injury alone does not cause significant hoarseness or cord paralysis. * **C: No effect:** While the voice may sound normal during routine conversation, there is a distinct functional deficit in pitch control and vocal strength. ### High-Yield Clinical Pearls for NEET-PG: * **Internal Laryngeal Nerve Injury:** Leads to anesthesia of the laryngeal mucosa above the vocal cords, increasing the risk of **aspiration**. * **Combined SLN and RLN Injury:** Results in the vocal cord being in the **cadaveric position** (midway between abducted and adducted). * **Wagner and Grossman Theory:** Suggests that if the SLN is intact in an RLN palsy, the vocal cord remains in the paramedian position due to the adducting action of the cricothyroid.

Q: A 38-year-old man presents with stridor following a respiratory infection. Cotton's grading is used to classify the pathology. Which of the following is the diagnosis?

Subglottic stenosis. **Explanation:** **Subglottic stenosis** is the correct diagnosis because **Cotton’s Grading System** is the gold-standard classification specifically used to quantify the severity of subglottic stenosis. It is based on the percentage of luminal narrowing: * **Grade I:** <50% obstruction * **Grade II:** 51–70% obstruction * **Grade III:** 71–99% obstruction * **Grade IV:** Complete obstruction (no detectable lumen) In this clinical scenario, the patient presents with **stridor** (a hallmark of airway narrowing) following a respiratory infection, which can trigger inflammatory stenosis or exacerbate a pre-existing subclinical narrowing. **Analysis of Incorrect Options:** * **Laryngeal Carcinoma:** While it causes stridor, it is staged using the **TNM classification**, not Cotton’s grading. * **Superior Laryngeal Nerve Palsy:** This typically presents with voice fatigue or loss of high-pitched notes (due to cricothyroid muscle paralysis) rather than fixed airway stenosis. * **Vocal Cord Misuse:** This leads to functional voice disorders or organic lesions like vocal nodules, which are not graded by Cotton’s system. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause:** Iatrogenic (prolonged endotracheal intubation) is the most common cause of acquired subglottic stenosis. * **Anatomical Site:** The subglottis is the narrowest part of the pediatric airway (at the level of the cricoid cartilage). * **Management:** Grade I and II are often managed conservatively or endoscopically (dilation/laser), while Grade III and IV usually require surgical reconstruction (Laryngotracheal reconstruction or Cricotracheal resection).

Question 1

Which laser is used in laryngeal work?

Accepted Answer

CO2

Answer

Argon

Answer

Nd:Yag

Answer

Holmium

Question 2

Reinke's space is seen in which of the following anatomical locations?

Accepted Answer

Vocal cords

Answer

Subglottis

Answer

Epiglottis

Answer

Pharynx

Question 3

Cadeveric position of vocal cords after thyroidectomy is typically due to which of the following?

Accepted Answer

Bilateral recurrent laryngeal nerve paralysis.

Answer

Unilateral recurrent laryngeal nerve paralysis.

Answer

Unilateral external laryngeal nerve paralysis.

Answer

Bilateral external laryngeal nerve paralysis.

Question 4

A one-day-old neonate presents with a weak cry since birth and biphasic stridor, suggestive of incomplete canalisation. What is the most common site of this defect?

Accepted Answer

Glottic

Answer

Supraglottic

Answer

Subglottic

Answer

Hypopharynx

Question 5

What is the most widely used treatment for recurrent respiratory papillomatosis?

Accepted Answer

CO2 laser ablation

Answer

Diathermy excision

Answer

Excision with microdebrider

Answer

Wait for spontaneous resolution

Question 6

In acute epiglottitis, what is the common cause of death?

Accepted Answer

Respiratory obstruction

Answer

Acidosis

Answer

Atelectasis

Answer

Laryngospasm

Question 7

Maximum stridor is seen in which condition of vocal cord paralysis?

Accepted Answer

Bilateral incomplete paralysis

Answer

Unilateral incomplete paralysis

Answer

Unilateral complete paralysis

Answer

Bilateral complete paralysis

Question 8

Laryngeal web most commonly involves which region?

Accepted Answer

Glottis

Answer

Supraglottitis

Answer

Subglottis

Answer

Both supraglottis and glottis

Question 9

Injury to the superior laryngeal nerve causes which of the following?

Accepted Answer

Loss of timbre of voice

Answer

Hoarseness

Answer

Paralysis of vocal cords

Answer

No effect

Question 10

A 38-year-old man presents with stridor following a respiratory infection. Cotton's grading is used to classify the pathology. Which of the following is the diagnosis?

Accepted Answer

Subglottic stenosis

Answer

Laryngeal carcinoma

Answer

Superior laryngeal nerve palsy

Answer

Vocal cord misuse

Diseases of the Larynx — MCQs

Diseases of the Larynx — MCQs

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