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DNB Otorhinolaryngology ENT Paper 3 — Complete Answers

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QUESTION 1 [10 Marks]

a) Muscles Responsible for Velopharyngeal Competence [3 Marks]

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b) Contraindications and Complications of Adenoidectomy [3+4 = 7 Marks]

1. Cleft palate (overt or submucous) — risk of VPI and hypernasality
2. Short palate / deep pharynx — inadequate VP closure post-operatively
3. Bifid uvula (indicator of submucous cleft)
4. Nasal regurgitation pre-operatively
5. Coagulation disorders (uncontrolled)

1. Active upper respiratory infection (defer 4–6 weeks)
2. Uncontrolled hypertension
3. Age <2 years (adenoids physiologically important)
4. Recent vaccination (live vaccines)

1. Haemorrhage — from adenoid bed or injury to Eustachian tube orifice
2. Injury to Eustachian tube — leads to otitis media
3. Injury to posterior pharyngeal wall
4. Damage to soft palate or uvula
5. Atlanto-axial subluxation (Grisel's syndrome) — rare but serious

1. Primary haemorrhage
2. Airway obstruction
3. Aspiration of blood/secretions
4. Nasopharyngeal stenosis (rare)

1. Velopharyngeal insufficiency (VPI) — hypernasality, nasal regurgitation (most important long-term complication)
2. Secondary haemorrhage (7–10 days)
3. Recurrence of adenoids (especially in children < 2 years)
4. Nasopharyngeal stenosis
5. Otitis media with effusion (paradoxical — if Eustachian tube function worsens)
6. Persistent rhinorrhoea
7. Grisel's syndrome — torticollis due to atlanto-axial subluxation from ligamentous laxity

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QUESTION 2 [10 Marks]

a) Differences Between Acute Laryngotracheobronchitis (Croup) and Acute Supraglottitis [5 Marks]

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b) Laryngoscopic Findings in Tuberculosis (TB) Laryngitis [5 Marks]

1. Posterior larynx (interarytenoid region) — most common
2. Vocal cords
3. Epiglottis
4. Aryepiglottic folds
5. Subglottis (least common)

• Hyperaemia and oedema of posterior larynx
• Superficial ulceration at interarytenoid fold ("turban epiglottis" appearance if epiglottis is involved)
• Pale, oedematous mucosa (contrasts with the hyperaemic appearance of carcinoma)

1. Mouse-nibbled ulcers — irregular, superficial ulcers with undermined edges on vocal cords
2. Turban epiglottis — diffuse, pale, oedematous thickening of epiglottis (pathognomonic)
3. Interarytenoid pachydermia — thickening/heaping of mucosa at the posterior commissure
4. Pale oedematous mucosa — diffuse, waterlogged appearance ("wet" oedema)
5. Vocal cord involvement — may appear nodular or ulcerated
6. Perichondritis — involvement of laryngeal cartilages causing fixity

• Granuloma formation
• Fibrosis and stenosis
• Immobility of vocal cords

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QUESTION 3 [10 Marks]

a) Labelled Diagram of Intrinsic Membranes of the Larynx [4 Marks]

• Extends from the lateral border of the epiglottis to the arytenoid cartilage
• Upper free border → forms the aryepiglottic fold (aryepiglottic ligament)
• Lower free border → forms the vestibular ligament (false vocal cord)

• A cone-shaped membrane
• Inferior attachment: Upper border of cricoid cartilage (cricothyroid membrane anteriorly)
• Superior free border: Forms the vocal ligament (true vocal cord)
• Anteriorly: The midportion thickens to form the cricothyroid ligament (median cricothyroid ligament)

DIAGRAM (Coronal cross-section):

     Epiglottis
        |
  Aryepiglottic fold ← Upper free border of Quadrangular Membrane
        |
  Vestibular fold (False cord) ← Lower free border of Quadrangular Membrane
        |
  ---- Laryngeal Ventricle ----
        |
  Vocal fold (True cord) ← Superior free border of Conus Elasticus
        |
  Conus Elasticus (Cricovocal Membrane)
        |
  Cricothyroid Ligament (Cricothyroid Membrane anteriorly)
        |
  Cricoid Cartilage

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b) Potential Spaces of the Larynx [6 Marks]

• Boundaries:
  • Anterior: Thyrohyoid membrane and thyroid cartilage
  • Posterior: Epiglottis and thyroepiglottic ligament
  • Superior: Hyoepiglottic ligament
• Contents: Fat, lymphatics
• Clinical importance: Invasion by supraglottic carcinoma; spread from vallecula. T3 disease when invaded.

• Boundaries:
  • Medial: Quadrangular membrane and conus elasticus
  • Lateral: Thyroid cartilage and cricothyroid membrane
  • Posterior: Pyriform sinus mucosa
• Contents: Fat, muscles
• Clinical importance: Connects supraglottis to glottis and subglottis; pathway for "transglottic spread" of carcinoma. Also known as the paraglottic compartment.

• Located between the vocal cord epithelium and the vocal ligament
• Loose areolar tissue space
• Clinical importance: Reinke's oedema (polypoid corditis) accumulates fluid here; voice changes. Important in vocal fold surgery.

• Between the inferior surface of the true vocal cord and the lower border of the cricoid
• Clinical importance: Subglottic extension of glottic carcinoma; T3/T4 staging

• Between the inner and outer layers of the aryepiglottic fold
• Clinical importance: Site of laryngeal cysts (saccular cysts)

• Between the two arytenoid cartilages posteriorly
• Clinical importance: Early site of TB laryngitis; carcinoma at posterior commissure

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QUESTION 4 [10 Marks]

a) Various Causes of Neonatal Stridor [4 Marks]

1. Laryngomalacia — Most common cause (60–75%), "omega-shaped" epiglottis, floppy arytenoids
2. Lingual thyroid / thyroglossal cyst
3. Mucus retention cyst
4. Laryngeal atresia (rare)

1. Vocal cord paralysis — 2nd most common; bilateral (central — Arnold-Chiari, hydrocephalus), unilateral (birth trauma, mediastinal masses)
2. Laryngeal web (congenital)
3. Laryngeal atresia

1. Congenital subglottic stenosis — 3rd most common
2. Subglottic haemangioma — presents after 2–3 months with worsening stridor; 50% have cutaneous haemangioma
3. Subglottic cyst

1. Tracheomalacia
2. Tracheal stenosis
3. Vascular ring / sling (double aortic arch, pulmonary artery sling)
4. Mediastinal mass (cystic hygroma, teratoma)

• Choanal atresia (stertor, not stridor)
• Pierre Robin sequence (micrognathia + glossoptosis)
• Macroglossia (Beckwith-Wiedemann syndrome)

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b) Calculation of Tracheostomy Tube Size in a Paediatric Patient [2 Marks]

ID (mm) = (Age in years / 4) + 4 (for uncuffed tube)

• Premature neonate: 2.5–3.0 mm ID (Bivona or Shiley neonatal)
• Term neonate: 3.0–3.5 mm
• 1 year: 3.5–4.0 mm

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c) Surgical Procedures for Paediatric Subglottic Stenosis [4 Marks]

• Grade I: <50% obstruction
• Grade II: 50–70% obstruction
• Grade III: 71–99% obstruction
• Grade IV: No detectable lumen

• For Grade I–II stenosis
• Single midline incision through cricoid and upper tracheal rings
• Intubation splints the airway open
• Avoids tracheostomy

• Anterior cartilage graft (usually costal cartilage) for anterior stenosis
• Posterior cartilage graft for posterior glottic stenosis / posterior subglottic stenosis
• Can be single-stage (no tracheostomy) or double-stage (stented with tracheostomy)
• Most commonly performed procedure for Grade II–III stenosis

• For Grade III–IV stenosis
• Resection of stenotic segment with primary thyrotracheal anastomosis
• Higher success rates for severe stenosis
• Preferred over LTR for Grade IV

• Temporising measure for severe cases or as adjunct to LTR

• CO₂ laser resection / balloon dilatation — Grade I–II
• Endoscopic radial incisions with mitomycin C application

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QUESTION 5 [10 Marks]

a) Various Phases of Deglutition [3 Marks]

• Oral preparatory stage: Food is chewed, mixed with saliva, and formed into a bolus
• Oral propulsive stage: Tongue propels bolus posteriorly toward the pharynx; lips sealed, teeth approximated
• Duration: Variable
• Controlled by the cerebral cortex (voluntary)

• Triggered when bolus contacts the anterior tonsillar pillars
• Duration: ~1 second
• Sequential events (all simultaneous/rapid): a. Velopharyngeal closure (levator veli palatini) — prevents nasal regurgitation b. Laryngeal elevation (hyoid rises 2 cm, larynx 2 cm) c. Epiglottis tilts posteriorly to cover laryngeal inlet d. Vocal cord adduction + false cord closure — airway protection e. Pharyngeal peristalsis (superior, middle, inferior constrictor sequentially) f. Cricopharyngeal relaxation (Killian's dehiscence area) — opening of UOS
• Breathing ceases momentarily (deglutition apnoea)

• Bolus passes through the oesophagus to the stomach
• Upper 1/3: striated muscle (voluntary control)
• Lower 2/3: smooth muscle (autonomous)
• Primary peristalsis propels bolus (10–15 seconds)
• Lower oesophageal sphincter (LOS) relaxes to allow entry into stomach
• Secondary peristalsis clears residual bolus

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b) Oesophageal Causes of Dysphagia [3 Marks]

1. Foreign body impaction

1. Oesophageal stricture (peptic — from GERD, most common benign cause)
2. Achalasia cardia — failure of LOS relaxation
3. Oesophageal webs (Plummer-Vinson/Patterson-Kelly syndrome — cervical web + iron deficiency)
4. Oesophageal rings (Schatzki's ring — at GE junction)
5. Oesophageal diverticula (Zenker's — pharyngo-oesophageal; Killian-Jamieson; mid-oesophageal)
6. Diffuse oesophageal spasm
7. Oesophagitis (eosinophilic, infective)
8. Systemic sclerosis (scleroderma) — smooth muscle atrophy

1. Carcinoma oesophagus (squamous — upper 2/3; adenocarcinoma — lower 1/3)

1. Mediastinal lymphadenopathy (TB, lymphoma)
2. Aortic aneurysm
3. Dysphagia lusoria — aberrant right subclavian artery
4. Retrosternal goitre
5. Lung carcinoma
6. Pericardial effusion

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c) Investigations in Management of Dysphagia [4 Marks]

• Detailed history and examination
• Cranial nerve assessment (IX, X, XII)

1. Barium swallow — first-line investigation; identifies webs, strictures, diverticula, motility disorders; "bird beak" sign in achalasia
2. Modified Barium Swallow (Video Fluoroscopy) — gold standard for pharyngeal phase dysphagia; real-time assessment of all phases
3. CT neck and chest — extrinsic compression, lymphadenopathy, malignancy
4. MRI — soft tissue details, neurological causes

1. Fibre-optic Endoscopic Evaluation of Swallowing (FEES) — bedside, dynamic assessment; reveals pooling, aspiration, penetration
2. Rigid/flexible oesophagoscopy — direct visualization; biopsy of lesions
3. Upper GI endoscopy — assessment of oesophageal lesions

1. Oesophageal manometry — motility disorders (achalasia, diffuse spasm, nutcracker oesophagus)
2. 24-hr pH monitoring — GERD-related strictures
3. Video laryngostroboscopy — vocal cord function assessment

1. MBS (Modified Barium Swallow) with various textures — guides diet modification
2. CT angiography — vascular causes (dysphagia lusoria)
3. Blood tests: CBC, iron studies (Plummer-Vinson), thyroid function

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QUESTION 6 [10 Marks]

a) Boundaries of Beahr's Triangle and Joll's Triangle [4+4 = 8 Marks]

• Described in thyroid surgery for identifying the external laryngeal nerve (EBSLN)
• Boundaries:
  • Medially: Midline of the neck / sternothyroid muscle
  • Laterally: Superior pole of the thyroid lobe (upper pole vessels)
  • Above/Superiorly: Sternohyoid muscle crossing
• Contents: External branch of the superior laryngeal nerve (EBSLN) — runs in this triangle before entering the cricothyroid muscle
• Surgical importance: The EBSLN is at risk during ligation of the superior thyroid pedicle. To protect it, the superior thyroid vessels should be ligated as close to the gland as possible, at the apex of Joll's triangle.

• Described to identify the recurrent laryngeal nerve (RLN)
• Boundaries:
  • Medially: Trachea / tracheoesophageal groove
  • Laterally: Common carotid artery
  • Superiorly: Inferior pole of thyroid lobe / Berry's ligament area
• Contents: Recurrent laryngeal nerve (in the tracheoesophageal groove)
• Surgical importance: RLN is at greatest risk near Berry's ligament (suspensory ligament of thyroid). The nerve must be identified before ligation of inferior thyroid artery.

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b) Semon's Law, Wagner's Law, and Grossman's Theory [1+1+1 = 3 Marks — but expanded for exam]

• States that in progressive organic lesions affecting the RLN, abductors (posterior cricoarytenoid) are paralysed before adductors (lateral cricoarytenoid)
• Thus, with partial RLN palsy, the cord lies in the paramedian position (not fully adducted or abducted)
• Clinical implication: An abductor paresis is an early sign; bilateral abductor palsy → respiratory distress

• Describes the position of the vocal cord in various degrees of nerve injury
• With complete unilateral RLN palsy: cord lies in cadaveric position (intermediate/paramedian)
• With incomplete palsy: cord remains near midline

• Explains the mechanism of cord position in unilateral RLN palsy
• Proposes that the cricothyroid muscle (innervated by the external branch of the SLN — not RLN) continues to function
• The cricothyroid adducts and tenses the cord → pulls it medially
• Therefore, in complete RLN palsy, the cord assumes the paramedian position (not lateral cadaveric position) due to intact cricothyroid action
• This explains why the cord is NOT in the fully abducted position even with complete RLN palsy

• Semon: Abductors first → paramedian position
• Wagner: Cadaveric (intermediate) position in complete palsy
• Grossman: Paramedian position due to intact cricothyroid action

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QUESTION 7 [10 Marks]

a) Patient Position for Rigid Bronchoscopy [1 Mark]

• Head is elevated on a rigid head-ring/pad and extended at the atlantooccipital joint
• Mouth opened widely
• This aligns the oral, pharyngeal, and tracheal axes into a straight line, allowing passage of the rigid bronchoscope

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b) Indications, Contraindications, Technique, and Complications [2+2+3+3 = 10 Marks]

1. Unexplained haemoptysis
2. Suspected foreign body (FB) inhalation — gold standard
3. Bronchial biopsy (carcinoma, sarcoidosis)
4. Evaluation of tracheal/bronchial stenosis
5. Unresolved pneumonia / atelectasis
6. Assessment before bronchial surgery

1. Foreign body removal (primary indication)
2. Management of massive haemoptysis
3. Laser resection of endobronchial tumours
4. Stent placement
5. Bronchial toileting in secretion retention
6. Dilatation of bronchial stenosis

1. Ankylosing spondylitis / cervical spine instability (cannot hyperextend neck)
2. Severe coagulopathy (uncorrected)
3. Unstable cardiovascular status

1. Recent myocardial infarction
2. Severe respiratory compromise (PaO₂ < 70 mmHg)
3. Aortic aneurysm
4. Trismus (limited mouth opening)

1. Pre-operative: Fasting 6 hrs, inform patient, IV access, monitoring
2. Anaesthesia: General anaesthesia (preferred); topical anaesthesia + sedation (adult)
3. Position: Supine with neck hyperextended (Boyce position / Jackson's position)
4. Lubrication of bronchoscope tip
5. Scope introduction: Over the tongue midline, identifies epiglottis → lifts epiglottis → visualizes vocal cords
6. Cords crossed with scope bevel rotated 90° (horizontal to vertical)
7. Scope advanced into trachea → carina identified
8. Systematic examination: Right bronchial tree first (more vertical), then left
9. For FB: Optical forceps passed through side channel; FB grasped and removed under direct vision
10. Ventilation: Through side port of bronchoscope (Hopkins rod ventilation)

1. Dental injury (tooth fracture, dental avulsion)
2. Laryngeal/tracheal trauma
3. Haemorrhage (especially with biopsy)
4. Desaturation / hypoxia
5. Cardiac arrhythmia
6. Oesophageal intubation (rare)
7. FB pushing further distally

1. Laryngeal/subglottic oedema → respiratory distress
2. Pneumothorax / surgical emphysema (especially with biopsy)
3. Respiratory failure
4. Laryngospasm
5. Mediastinitis (rare)
6. Bronchospasm

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QUESTION 8 [10 Marks]

a) Narrow Band Imaging (NBI) — Principle and Clinical Applications [4 Marks]

• NBI is an optical image enhancement technology developed by Olympus
• Uses filtered light at two specific wavelengths instead of white light:
  • 415 nm (blue light) — absorbed by haemoglobin in superficial capillaries (mucosal layer) → highlights intraepithelial papillary capillary loops (IPCL)
  • 540 nm (green light) — penetrates deeper to highlight submucosal vessels
• Since blood vessels absorb these narrow wavelengths intensely, they appear dark brown/green-black against the pinkish mucosa
• No dyes required — purely optical (unlike chromoendoscopy)

• IPCLs (Intraepithelial Papillary Capillary Loops) — crucial markers of mucosal disease
• Normal IPCLs: Regular, fine, loop-like pattern
• Abnormal/malignant IPCLs: Dilated, irregular, elongated, tortuous, varied calibre

1. Detection of early mucosal carcinoma — hypopharynx, larynx, oropharynx (brown spot sign indicates IPCL abnormality)
2. Delineation of tumour margins — more accurate than white light endoscopy
3. Differentiating benign vs malignant lesions:
   • Type I/II IPCL → benign (leukoplakia, papilloma)
   • Type IV/V IPCL → high suspicion of malignancy
4. Assessment of vocal cord lesions — pre-malignant changes, CIS, invasive carcinoma
5. Surveillance after chemoradiotherapy — residual/recurrent disease detection
6. Oesophageal cancer — Barrett's oesophagus, squamous cell carcinoma detection
7. Second primary tumour detection in head and neck cancer patients (panendoscopy with NBI)

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b) Vocal Registers [3 Marks]

• Lowest register
• Frequency: 20–50 Hz
• Vocal folds are lax, thick; short bursts of vibration with long closed phase
• Sound: Creaky, popping, low-pitched (like bacon sizzling)
• Not used in standard speech; used in some singing styles

• Normal speaking and singing register
• Frequency: ~100–350 Hz (males 100–150 Hz; females 200–300 Hz)
• Full length of vocal fold vibrates with complete adduction
• Most commonly used in everyday speech
• Rich in lower harmonics

• Higher pitched register
• Frequency: 300–1000 Hz
• Only the medial edges of cords vibrate (thin, stretched cords)
• Shorter closed phase
• Breathy quality; used in upper range singing

• Highest register
• Frequency: >1000 Hz (up to 2500 Hz)
• Mechanism debated — possible air jet between partially adducted cords
• Only some singers (coloratura sopranos) can produce this
• Extremely high-pitched

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c) Parameters Measured on Video Laryngostroboscopy [3 Marks]

• Absent mucosal wave → invasion of vocal ligament/muscle (carcinoma, scar)
• Reduced mucosal wave → Reinke's oedema, polyp, cyst
• Incomplete glottic closure → paralysis, paresis, bowing, sulcus vocalis

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QUESTION 9 [10 Marks]

a) Physiological Actions of Thyroid Hormones [4 Marks]

• Increase basal metabolic rate (BMR) — most important action
• Increase oxygen consumption in most tissues (except brain, testis, spleen)
• Calorigenic effect — heat production
• Increase Na⁺/K⁺-ATPase activity

• Increase glucose absorption from gut
• Increase gluconeogenesis and glycogenolysis
• Enhance insulin-mediated glucose uptake by cells
• Overall: Raise blood glucose (diabetogenic at high doses)

• Physiological amounts: Anabolic (promote protein synthesis)
• Excess: Catabolic (protein breakdown, muscle wasting)

• Increase lipolysis (fat breakdown)
• Increase cholesterol synthesis AND degradation (degradation > synthesis → net decrease in serum cholesterol)
• Hypothyroidism → hypercholesterolaemia

• Increase heart rate, force of contraction, cardiac output
• Decrease peripheral vascular resistance
• Increase β-adrenergic receptor sensitivity

• Essential for skeletal maturation (ossification)
• Critical for CNS maturation in fetal and neonatal life — deficiency → cretinism
• Stimulate GH secretion and IGF-1 production

• Maintain normal reflexes and mentation
• Excess → tremor, hyperreflexia, anxiety

• Necessary for normal gonadal function
• Hypothyroidism → menorrhagia, anovulation

• Stimulate erythropoietin production → increased red cell mass

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b) Physiological Actions of Parathyroid Hormone (PTH) and Calcitonin [4+2 = 6 Marks]

• Secreted by chief cells of the parathyroid gland
• Target organs: Bone, kidney, intestine (indirect via Vitamin D)
• Overall effect: RAISES serum calcium; LOWERS serum phosphate

1. Activates osteoclasts → bone resorption → releases Ca²⁺ and PO₄³⁻ into blood
2. Stimulates RANKL on osteoblasts → osteoclast differentiation
3. Continuous PTH: Catabolic (bone resorption)
4. Pulsatile/low-dose PTH: Anabolic (used therapeutically in osteoporosis — teriparatide)

1. Increases Ca²⁺ reabsorption in distal tubule (DCT) → retains calcium
2. Decreases PO₄³⁻ reabsorption in proximal tubule → phosphaturia (lowers serum PO₄)
3. Stimulates 1α-hydroxylase → converts 25(OH)D to active 1,25(OH)₂D (calcitriol)
4. Increases cAMP in urine (marker of PTH activity)

1. Via calcitriol → increases calcium and phosphate absorption from gut

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• Secreted by parafollicular C cells of the thyroid gland
• 32-amino acid peptide
• Overall effect: LOWERS serum calcium (physiological antagonist of PTH)

1. Inhibits osteoclast activity → reduces bone resorption
2. Net effect: calcium remains in bone → lowers serum Ca²⁺

1. Inhibits Ca²⁺ and PO₄³⁻ reabsorption → increases urinary excretion of both
2. Decreases serum calcium and phosphate

1. Decreases Ca²⁺ absorption (minor effect)

• Tumour marker for medullary thyroid carcinoma (C-cell tumour) — serum calcitonin elevated
• Used therapeutically for Paget's disease, osteoporosis, hypercalcaemia (salmon calcitonin nasal spray)

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QUESTION 10 [3 Marks shown — answer expanded for 10 marks]

Various Types of Conservation Laryngectomies [10 Marks]

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• Type I: Subepithelial cordectomy
• Type II: Subligamental cordectomy
• Type III: Transmuscular cordectomy
• Type IV: Total cordectomy
• Type V: Extended cordectomy (a-e subtypes involving arytenoid, subglottis, ventricle, etc.)

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• Midline thyrotomy + excision of one vocal cord
• For T1a glottic carcinoma
• Historical procedure; largely replaced by TLM

• Excision of anterior 2/3 of one cord + anterior commissure + small portion of opposite cord
• For T1 glottic with anterior commissure involvement

• Excision of one vertical half of the larynx
• For T1b, T2 glottic carcinoma
• Voice preserved via mucosal reconstruction; breathing through stoma initially

• Includes one arytenoid or subglottis
• For selected T2–T3 glottic tumours

• Excision of all structures above the true vocal cords (false cords, epiglottis, aryepiglottic folds, upper half of thyroid cartilage)
• Preserves: True vocal cords, arytenoids, cricoid
• For T1–T2 supraglottic carcinoma
• Voice: Normal; swallowing needs rehabilitation (aspiration risk)

• Includes base of tongue, pyriform sinus, one arytenoid
• For T3 supraglottic carcinoma

• SCL with cricohyoidopexy (CHP): Epiglottis retained; for supraglottic tumours
• SCL with cricohyoidoepiglottopexy (CHEP): Epiglottis removed; for glottic tumours

• For T2–T3 glottic and transglottic carcinoma
• Voice: Functional (arytenoid-epiglottis/hyoid contact produces sound)
• No permanent tracheostomy needed
• Considered the most oncologically versatile conservation procedure

• Total laryngectomy + creation of a tracheopharyngeal shunt using a strip of mucosa
• Requires permanent tracheostomy
• Voice: Shunt phonation (tracheopharyngeal voice without prosthesis)
• For advanced T3–T4 glottic carcinoma

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1. Adequate pulmonary function (FEV₁ >50%) — to tolerate aspiration
2. No cartilage invasion (relative)
3. At least one mobile arytenoid
4. No subglottic extension >1 cm
5. No bilateral cord fixation
6. Patient compliance and motivation for rehabilitation

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