What is the approach to diagnose laryngitis?

Diagnosing Laryngitis: A Systematic Approach

Laryngoscopy is the cornerstone of diagnosing laryngitis and should be performed when dysphonia persists beyond 4 weeks or when a serious underlying cause is suspected regardless of duration. 1

Initial Assessment

History and Physical Examination

• Assess for key symptoms:
  • Duration of hoarseness/dysphonia
  • Pattern (constant vs. intermittent)
  • Associated symptoms (cough, dysphagia, odynophagia)
  • Vocal demands (professional voice user)
  • Smoking and alcohol history
  • Recent respiratory infection
  • Recent intubation or neck surgery

Red Flag Symptoms Requiring Immediate Laryngoscopy

• Hoarseness with:
  • Hemoptysis
  • Dysphagia or odynophagia
  • Accompanying neurologic symptoms
  • Unexplained weight loss
  • Neck mass
  • Worsening symptoms
  • Immunocompromised status
  • Possible foreign body aspiration
  • Post-surgical (especially after intubation or neck surgery) 1

Diagnostic Algorithm

Step 1: Determine Urgency

• Immediate laryngoscopy (do not wait) if:
  • Any red flag symptoms present
  • Professional voice user (singers, teachers)
  • Suspected malignancy
  • Airway compromise 1, 2

Step 2: For Non-Urgent Cases

• If likely viral laryngitis without red flags:
  • Can observe for up to 4 weeks
  • Must perform laryngoscopy if symptoms persist beyond 4 weeks 1

Step 3: Laryngoscopic Examination

• Options include:
  • Transoral mirror examination
  • Rigid endoscopy
  • Flexible fiberoptic or distal-chip laryngoscopy
  • Stroboscopy (preferred for subtle abnormalities) 1

Step 4: Additional Testing Based on Findings

• Do not obtain CT or MRI before laryngoscopy 1
• Consider microbiological examination if ulcerative changes are present 3

Diagnostic Features on Laryngoscopy

Acute Laryngitis

• Diffuse erythema and edema of vocal folds
• Possible fibrinous exudate
• Preserved vocal fold mobility 4

Chronic Laryngitis

• Persistent vocal fold edema
• Hyperemia
• Possible epithelial thickening
• May see nodules or polyps in cases of vocal overuse 4, 5

Ulcerative Laryngitis

• Hyperemia and infiltration of vocal folds
• Erosions or ulcers covered with fibrin
• Typically symmetrical in middle third of vocal folds
• Decreased amplitude and irregular vibrations on stroboscopy 3

Special Considerations

Professional Voice Users

• Lower threshold for laryngoscopy (consider within 2-3 weeks of symptoms)
• Higher susceptibility to microvascular lesions and vocal fold hemorrhage
• May require stroboscopy to detect subtle abnormalities 2, 5

Post-Surgical Patients

• Expedited evaluation needed, especially after thyroid or cervical spine surgery
• Important to rule out vocal fold paralysis or intubation trauma 1, 2

Common Pitfalls to Avoid

1. Delayed diagnosis: Waiting too long before performing laryngoscopy can lead to missed malignancy or delayed treatment of serious conditions 1

2. Premature imaging: Obtaining CT or MRI before laryngoscopy is not recommended and exposes patients to unnecessary radiation and cost 1

3. Misdiagnosis as viral laryngitis: Many cases initially diagnosed as "acute laryngitis" are later found to have different pathologies after laryngoscopy 1

4. Overlooking fungal causes: Fungal laryngitis (especially in inhaler users) requires laryngoscopy for diagnosis and must be distinguished from malignancy 1

5. Inappropriate antibiotic use: Antibiotics have no proven benefit in treating acute laryngitis and should not be routinely prescribed 6

The diagnostic approach to laryngitis requires careful consideration of symptoms, risk factors, and appropriate timing of laryngoscopy to ensure accurate diagnosis and optimal outcomes for patients with voice disorders.