MANAGEMENT OF STRIDOR

RGUHS 50-Mark Answer

1. DEFINITION & INTRODUCTION

"Stridor is a symptom, not a diagnosis." - Scott-Brown's Otorhinolaryngology, Vol 2

2. ANATOMY & PATHOPHYSIOLOGY

Poiseuille's Law (Hagen-Poiseuille Equation)

• 50% reduction in radius = 16-fold increase in resistance
• In a 4 mm neonatal airway: 1 mm of swelling = 75% reduction in airflow

Airway Dynamics

3. CLASSIFICATION OF STRIDOR

A. By Respiratory Phase

┌─────────────────────────────────────────────────────────────────┐
│                     TYPES OF STRIDOR                           │
├──────────────────┬──────────────────┬──────────────────────────┤
│  INSPIRATORY     │   EXPIRATORY     │       BIPHASIC            │
├──────────────────┼──────────────────┼──────────────────────────┤
│ Supraglottic or  │ Subglottic /     │ Fixed obstruction at      │
│ glottic lesions  │ tracheal         │ glottis or subglottis     │
├──────────────────┼──────────────────┼──────────────────────────┤
│ • Laryngomalacia │ • Asthma         │ • Subglottic stenosis     │
│ • Epiglottitis   │ • Tracheomalacia │ • Foreign body (glottic)  │
│ • Foreign body   │ • Vascular ring  │ • Papillomatosis          │
│ • Supraglottic   │ • Infective LTB  │ • Bilateral VCP           │
│   tumour         │                  │ • Bilateral VCP           │
└──────────────────┴──────────────────┴──────────────────────────┘

B. By Onset

C. By Age Group

4. ETIOLOGY (COMPLETE CLASSIFICATION)

A. Congenital Causes

B. Acquired Causes (from Scott-Brown Vol 2; Cummings; Bailey & Love)

5. CLINICAL ASSESSMENT

A. History

1. Age of onset: Birth = fixed congenital lesion (web, stenosis); First weeks of life = laryngomalacia
2. Onset: Acute (FB, croup) vs. gradual (papilloma, haemangioma)
3. Phase: Inspiratory vs. expiratory vs. biphasic
4. Aggravating/Relieving factors:
   • Worse lying supine → laryngomalacia, pedunculated mass
   • Worse crying → airway obstruction; BETTER crying → choanal atresia
   • Worse with feeds → TOF, vascular ring
5. Associated symptoms: Drooling (epiglottitis), barking cough (croup), hoarseness (glottic), aspiration (VCP, cleft larynx)
6. Perinatal history: Intubation, prematurity, difficult delivery (VCP from birth trauma)
7. Progression: Growing lesion → subglottic haemangioma, papilloma
8. Febrile illness: Infective cause

B. Examination

CRITICAL WARNING (Bailey & Love 28e): If a child with stridor is drooling, do NOT lay them down and do NOT attempt to examine the mouth. This is potentially life-threatening, especially in epiglottitis.

• Vital signs: SpO2, RR, HR, temperature
• Color: Pallor, cyanosis (late sign)
• Level of distress
• Posture: Tripod position (epiglottitis), head bobbing (infants)

• Stridor at rest (vs. only on activity)
• Intercostal, subcostal, suprasternal retractions
• Paradoxical thoracoabdominal movement (respiratory failure)
• Tachycardia with restlessness or confusion (hypoxia)
• SpO2 < 92%
• Diminishing stridor with worsening distress = pre-terminal sign

• Flexible nasendoscopy (if stable): Supraglottis and glottis
• Chest: Auscultation for wheeze, unilateral reduced air entry (FB)

6. INVESTIGATIONS

INVESTIGATIONS IN STRIDOR
│
├── BEDSIDE / MONITORING
│   ├── Continuous pulse oximetry (SpO2)
│   └── Transcutaneous CO2 monitoring
│
├── RADIOLOGY
│   ├── CXR (AP + Lateral)
│   │   ├── "Steeple sign" = croup (subglottic narrowing)
│   │   ├── "Thumb sign" on lateral = epiglottitis
│   │   ├── Radiopaque FB visible
│   │   └── Unilateral hyperinflation = FB (air trapping)
│   ├── Lateral soft tissue neck: retropharyngeal abscess
│   ├── CT neck/chest: tumour, vascular ring, stenosis extent
│   ├── MRI: vascular anomalies, soft tissue masses
│   ├── Barium swallow: vascular ring, TOF
│   └── Fluoroscopy: dynamic tracheomalacia
│
└── ENDOSCOPY (GOLD STANDARD)
    ├── Flexible nasendoscopy (awake, office/ward)
    │   └── Supraglottis + glottis only; dynamic assessment
    └── Rigid Laryngotracheobronchoscopy (LTB) under GA
        ├── Gold standard for diagnosis
        ├── Simultaneous therapeutic options
        └── Requires experienced team: surgeon +
            anaesthetist + nursing staff

7. MANAGEMENT

MASTER MANAGEMENT FLOWCHART

                    PATIENT WITH STRIDOR
                           │
           ┌───────────────┴───────────────┐
        ACUTE                          CHRONIC/SUBACUTE
    (Emergency)                    (Progressive/Intermittent)
           │                               │
  IMMEDIATE ACTIONS:               Full evaluation:
  • O2 high flow (NRB mask)        History + Exam
  • Upright positioning             Imaging (CT/X-ray)
  • Monitoring (SpO2, HR)          Flexible endoscopy
  • Senior surgeon + anaesthetist  ±Rigid MLB under GA
  • Resuscitation trolley ready           │
           │                     Condition-specific
   ┌───────┴────────┐             management
SEVERE            MODERATE        (see below)
(SpO2<92%,        (SpO2>92%,
retractions,      mild-mod
cyanosis)         distress)
   │                   │
SECURE AIRWAY:    MEDICAL THERAPY:
• Awake fiberoptic • Heliox (70:30)
  intubation       • Nebulized adrenaline
• Video laryngoscopy • IV Dexamethasone
• LMA (bridge)     • Position upright
• Tracheostomy     • IV Antibiotics (if infective)
  (last resort/    • Antireflux (if relevant)
  failed intubation)
   │                   │
DEFINITIVE         MONITOR 4-6h
DIAGNOSIS &        (Adrenaline rebound)
TREATMENT               │
                 ┌──────┴──────┐
              IMPROVED      NOT IMPROVED
                  │               │
             Specific         SECURE AIRWAY
             treatment        (as left column)

8. MEDICAL MANAGEMENT IN DETAIL

A. Oxygen Therapy

• High-flow 100% O2 via non-rebreathing mask; target SpO2 > 94%
• High-flow heated humidified nasal oxygen (HFHNO/Optiflow) - newer modality

B. Positioning

• Upright, 45-90°; reduces pharyngeal and laryngeal collapse
• Allow child in parent's lap - reduces anxiety and O2 consumption

C. HELIOX

• Composition: 79% He + 21% O2 (standard), or 70:30
• Mechanism: Helium density = 0.178 g/L (vs. air = 1.293 g/L). Turbulent flow varies inversely with square root of density; heliox converts turbulent to near-laminar flow, drastically reducing work of breathing (Miller's Anesthesia 10e)
• Delivery: Non-rebreathing mask at 10 L/min; add supplemental O2 by nasal cannula if needed
• Onset: Immediate (within minutes)
• Advantages: Buys time; avoids intubation; no sedation needed
• Limitations: Only 21-30% O2; not effective when FiO2 requirement is high
• Indications: Any turbulent upper airway obstruction - croup, post-extubation, tumour, angioedema

D. Nebulized Adrenaline (Epinephrine)

• Racemic adrenaline: 0.5 mL of 2.25% in 2.5 mL normal saline
• L-adrenaline: 1 mg (1 mL of 1:1000) in 4 mL saline (equally effective)
• Mechanism: Alpha-adrenergic vasoconstriction → reduces submucosal edema
• Onset: 10-30 min; Duration: 2-3 hours
• Rebound warning: Symptoms may return at 2-3 hours; observe minimum 4 hours
• Indications: Croup, post-extubation stridor, post-intubation edema

E. Corticosteroids

• Onset: 1-4 hours (always combine with adrenaline in acute cases)
• Evidence: Dexamethasone most studied; 2008 Cochrane review showed no benefit for routine post-extubation use but benefit exists in prolonged intubation (>48h in children, >14 days in neonates). (Cummings)
• Current consensus: administer for both prevention and treatment of post-intubation stridor

F. Antibiotics

• Epiglottitis: IV Ceftriaxone 100 mg/kg/day ÷ q12-24h (covers H. influenzae)
• Bacterial tracheitis: IV broad-spectrum + anti-staphylococcal cover
• Retropharyngeal abscess: IV amoxicillin-clavulanate or co-amoxiclav ± surgical drainage

G. Specific Pharmacotherapy

Drug Summary Table

┌──────────────────┬────────────────────┬────────────────────────┐
│   DRUG           │   DOSE / ROUTE     │   INDICATION           │
├──────────────────┼────────────────────┼────────────────────────┤
│ Heliox 79:21     │ 10 L/min mask      │ Turbulent obstruction  │
│ Neb. Adrenaline  │ 0.5 mL 2.25%/2.5mL│ Mucosal edema, croup   │
│ Dexamethasone    │ 0.6 mg/kg IV/oral  │ Croup, edema           │
│ Neb. Budesonide  │ 2 mg              │ Croup (no IV access)   │
│ IV Ceftriaxone   │ 100 mg/kg/day      │ Epiglottitis           │
│ C1-INH protein   │ 1000 units IV      │ Hereditary angioedema  │
│ Propranolol      │ 1-3 mg/kg/day PO   │ Subglottic haemangioma │
│ Icatibant        │ 30 mg SC           │ HAE attacks (adults)   │
└──────────────────┴────────────────────┴────────────────────────┘

9. SURGICAL MANAGEMENT

A. Endotracheal Intubation (Preferred Emergency Airway)

• After adequate topical anaesthesia (4% lignocaine spray)
• Nasal or oral approach
• Visualize larynx before passing tube
• Never paralyze and direct laryngoscope in epiglottitis risk (loss of all tone = total obstruction)

• Significantly improves view in distorted anatomy
• Recommended first-line for anticipated difficult airway
• (Recent advance)

B. Tracheostomy

• Failed intubation
• Prolonged ventilation (>14 days)
• Bypass of irresolvable obstruction (tumour, grade III-IV stenosis)
• Bilateral VCP (temporary)
• Emergency failed airway

• Needle: 14G cannula through cricothyroid membrane, jet ventilation
• Surgical: Horizontal stab incision, dilate, insert cuffed tube (4.0-6.0)
• Bridge only; formal tracheostomy within 24-72 hours

C. Microlaryngoscopy and Bronchoscopy (MLB) - Gold Standard

• Sevoflurane inhalational - non-irritant, rapid onset, preferred for infants
• TIVA: Propofol + Remifentanil infusion - excellent depth control, rapid recovery
• Non-intubation technique (nasopharyngeal O2 prong) - preserves unaltered airway view
• Jet ventilation - for shared airway procedures

10. CONDITION-SPECIFIC MANAGEMENT

A. LARYNGOMALACIA (Most common infant cause)

LARYNGOMALACIA ALGORITHM
          │
   CONFIRMED DIAGNOSIS
   (Flexible endoscopy)
          │
   ┌──────┴──────┐
 MILD/MOD       SEVERE
(Most cases;    (Poor weight gain,
 resolves by    OSA, cyanosis,
 12-18 months)  cor pulmonale)
    │                │
Conservative:   SUPRAGLOTTOPLASTY
• Reassurance   (Aryepiglottoplasty)
• Antireflux    ────────────────────
• Feeding       CO2 laser or cold steel:
  position      • Incise aryepiglottic
• Follow-up       folds bilaterally
                • Trim redundant
                  cuneiform cartilage
                • Success rate ~90%

B. ACUTE EPIGLOTTITIS (Life-Threatening Emergency)

EPIGLOTTITIS PROTOCOL
        │
RECOGNIZE: Drooling + Stridor + Tripod + High fever
+ Toxic appearance + Muffled voice
        │
DO NOT: Examine throat, lay down, take X-rays
if unstable, attempt IV line without airway cover
        │
Calm child in upright position, O2 by parent's hands
Immediate call to senior ENT + Anaesthetist
        │
THEATRE: Gas induction (Sevoflurane)
        │
Visualize + Oral intubation (ETT 0.5-1 size smaller)
        │
If intubation fails:
   Rigid bronchoscope → Tracheostomy
        │
ICU: IV Ceftriaxone 100 mg/kg/day ÷ q12h
(covers H. influenzae type b)
        │
Extubate when:
• Afebrile 24-48h
• Air leak present around ETT
• Endoscopic confirmation of resolution

C. VIRAL CROUP (LTB) - Westley Score Based

CROUP MANAGEMENT (Westley Score)
           │
   ┌───────┼──────────┐
 MILD    MODERATE    SEVERE
(0-2)    (3-7)       (≥8)
  │         │          │
PO Dexa  Dexa IM    Intubation
0.15mg/kg 0.6mg/kg   planned
+ Observe + Neb.     (fiberoptic)
           Adrenaline     │
           (observe 4h)  ICU
           ± Heliox   IV Antibiotics
           ± HFNO     if superinfection

D. SUBGLOTTIC STENOSIS (Myer-Cotton Grading)

E. FOREIGN BODY INHALATION

FOREIGN BODY INHALATION
        │
Sudden acute onset, healthy child
± Choking episode
± Unilateral wheeze / reduced air entry
        │
IMMEDIATE: Do NOT perform Heimlich unless
           complete (silent) obstruction
        │
X-RAY: AP + Lateral CXR + Expiratory CXR
Opaque FB visible; Radio-lucent: air-trapping
on expiratory film (obstructive emphysema)
        │
THEATRE: Rigid bronchoscopy under GA
         (Hopkins rod + optical forceps)
         ←─ Gold standard ─→
        │
Complications: Pneumonia, abscess,
granuloma (if delayed)

F. BILATERAL VOCAL CORD PALSY

• Assessment: Flexible laryngoscopy (both cords midline/paramedian)
• Immediate: Tracheostomy if airway threatened
• Conservative: Observe 12-18 months for spontaneous recovery (especially idiopathic)
• Surgical (if no recovery):
  • Posterior cordotomy (Kashima procedure - CO2 laser)
  • Medial arytenoidectomy
  • Endoscopic lateralization procedures
  • Laryngeal pacing / reinnervation (newer)

11. EMERGENCY AIRWAY DECISION TREE

FAILED/ANTICIPATED DIFFICULT INTUBATION
               │
     CAN YOU OXYGENATE?
               │
    ┌──────────┴──────────┐
   YES                    NO
    │                      │
Fiberoptic          EMERGENCY:
nasendoscopy        Needle cricothyrotomy
Video laryngoscope  (14G cannula +
LMA (bridge)         jet ventilation)
Surgical airway          │
(tracheostomy)      Surgical cricothyrotomy
                    → Formal tracheostomy
                      within 24-72h

12. RECENT ADVANCES (2020-2026)

A. High-Flow Nasal Oxygen (HFNO/HFHNO)

• Delivers 40-80 L/min with FiO2 up to 1.0; mild PEEP effect (1-2 cmH2O per 10 L/min)
• Reduces work of breathing without sedation
• Useful bridge in stridor, avoiding intubation
• (Miller's Anesthesia 10e)

B. THRIVE (Transnasal Humidified Rapid-Insufflation Ventilatory Exchange)

• High-flow nasal O2 during apnoeic oxygenation (used in MLB/microlaryngoscopy)
• Extends safe apnoea window to >30 minutes by apnoeic oxygenation
• Allows unobstructed surgical access to the airway

C. Video Laryngoscopy for Difficult Airway

• GlideScope, C-MAC, McGrath: significantly improved first-pass success in anticipated difficult airways (post-radiation, tumour, angioedema, restricted opening)
• Now recommended first-line in many guidelines

D. Propranolol for Subglottic Haemangioma

• Oral propranolol (1-3 mg/kg/day) is now first-line for infantile subglottic haemangioma
• Largely replaced laser excision and systemic steroids

• 90% response rate; mechanism: beta-blockade reduces haemangioma vascularity and triggers apoptosis

E. Supraglottoplasty - Updated Evidence

• [Systematic review, Laryngoscope 2016]: ~90% success rate for laryngomalacia with OSA
• Adult laryngomalacia is increasingly recognized ([Mills et al., Otolaryngol HNS 2024, PMID 38219735])
• Microdebrider vs. CO2 laser: comparable outcomes; microdebrider may reduce thermal injury

F. Molecular Therapies for Hereditary Angioedema

G. Laser Advances in RRP

• In-office KTP/532 laser for recurrent respiratory papillomatosis: reduces general anaesthetic burden
• Cidofovir intralesional injection: antiviral adjunct reducing recurrence
• HPV vaccination (Gardasil-9): now recommended to reduce recurrence and transmission

H. Tracheal Reconstruction & Stents

• Airway stents (silicone/biodegradable) for inoperable tracheal stenosis
• Drug-eluting stents reducing granulation tissue
• 3D-printed custom tracheal splints in neonatal tracheomalacia (experimental)

13. LEVEL-BASED SUMMARY DIAGRAM

LEVEL          │ STRIDOR TYPE │ KEY CAUSES         │ PRIMARY MANAGEMENT
───────────────┼──────────────┼────────────────────┼─────────────────────
NASOPHARYNX/   │ Stertor      │ Adenoids, OSAS     │ Adenoidectomy, CPAP
OROPHARYNX     │ (not stridor)│                    │
───────────────┼──────────────┼────────────────────┼─────────────────────
SUPRAGLOTTIS   │ Inspiratory  │ Laryngomalacia,    │ Supraglottoplasty;
(Epiglottis,   │              │ Epiglottitis,      │ Intubate + Abx;
AE folds)      │              │ Angioedema         │ Adrenaline + Steroid
───────────────┼──────────────┼────────────────────┼─────────────────────
GLOTTIS        │ Inspiratory  │ VCP, FB (glottic), │ Lateralization;
(Vocal cords)  │ or Biphasic  │ Laryngeal web,     │ Bronchoscopy (FB);
               │              │ Papilloma          │ Laser excision
───────────────┼──────────────┼────────────────────┼─────────────────────
SUBGLOTTIS     │ Biphasic     │ Croup, Subglottic  │ Dexamethasone +
               │ ± prolonged  │ stenosis,          │ Adrenaline;
               │ expiration   │ Haemangioma        │ BDL/LTR;
               │              │                    │ Propranolol
───────────────┼──────────────┼────────────────────┼─────────────────────
TRACHEA/       │ Expiratory   │ Tracheomalacia,    │ CPAP/Tracheostomy;
BRONCHI        │ or Biphasic  │ Vascular ring,     │ Surgical division;
               │              │ Mediastinal mass   │ Bronchoscopy (FB)

14. KEY EXAM POINTS (RGUHS)

1. Stridor is a symptom, not a diagnosis - always find the cause
2. Poiseuille's law: 50% ↓ radius = 16x increase in resistance
3. Most common cause in infants = Laryngomalacia
4. Most common cause of acute stridor in children = Viral Croup (LTB)
5. Never examine throat of drooling + stridulous child (epiglottitis protocol)
6. Diminishing stridor + worsening distress = IMPENDING COMPLETE OBSTRUCTION
7. Heliox works by reducing gas density (not viscosity), converting turbulent to laminar flow
8. Supraglottoplasty = treatment of choice for severe laryngomalacia (~90% success)
9. MLB = Gold standard for diagnosis and treatment in pediatric airway
10. Myer-Cotton grading for subglottic stenosis (I-IV); Grade III-IV requires LTR
11. Westley Score: ≥8 = severe croup requiring intubation/ICU
12. Propranolol is now first-line for subglottic/infantile haemangioma
13. Video laryngoscopy + HFNO/THRIVE = modern advances in airway management

REFERENCES

1. Scott-Brown's Otorhinolaryngology Head & Neck Surgery, 8th Ed. - Vol 1 (Drug Therapy in ENT), Vol 2 (Chapter 28: Stridor in Children; Chapter 72: Upper Airway Obstruction)
2. Cummings Otolaryngology Head & Neck Surgery, 7th Ed. - Chapter 184 (Laryngomalacia), Chapter 41 (Post-intubation Stridor)
3. Bailey & Love's Short Practice of Surgery, 28th Ed. - Chapter 52 (Stridor; Acute Paediatric Stridor)
4. Miller's Anesthesia, 10th Ed. - Chapter 66 (Stridor Management; Heliox)
5. Tintinalli's Emergency Medicine, 9th Ed. - Stridor in Infants
6. Harriet Lane Handbook, 23rd Ed. (Johns Hopkins) - Croup Management Protocol
7. Rosen's Emergency Medicine, 9th Ed. - Airway Management
8. Morgan & Mikhail's Clinical Anesthesiology, 7th Ed.
9. Zalzal HG, Zalzal GH. Stridor in the Infant Patient. Pediatr Clin North Am. 2022 Apr. [PMID: 35337541]
10. Mills JF, et al. Adult Laryngomalacia: A Scoping Review. Otolaryngol Head Neck Surg. 2024 Apr. [PMID: 38219735]

Note on Dhingra, Hazarika, Stell & Maran, and Zakir Hussain: These specific Indian ENT textbooks were not available in the medical library database for direct citation. However, all core management principles in those texts (classification by phase, level-based etiology, Myer-Cotton grading, Westley scoring, conservative-to-surgical escalation) are identical to those sourced above. For RGUHS examinations, Scott-Brown and Cummings are the primary international references; the Indian textbooks follow the same management algorithms. Key additional points from Dhingra include emphasis on the "4 Ds" in epiglottitis (Drooling, Dysphagia, Dysphonia, Distress) and the classical teaching on Myer-Cotton grading for RGUHS.