Can hyperthyroidism cause laryngitis?

Hyperthyroidism and Laryngitis: The Connection

Hyperthyroidism can cause laryngitis through several mechanisms, including direct effects on laryngeal tissues via thyroid hormone receptors and indirect effects through associated conditions. 1, 2

Pathophysiological Mechanisms

Direct Effects

• Thyroid hormone receptors in the larynx: Research has identified both TR-alpha and TR-beta thyroid hormone receptors in the human larynx, specifically in:

  • Fibrous connective tissue of the lamina propria
  • Cartilage
  • Glandular elements 1

• This receptor presence implies that thyroid hormone dysregulation in hyperthyroidism directly affects laryngeal tissues, potentially causing inflammation and voice changes.

Indirect Effects

• Thyroid enlargement: Hyperthyroidism, especially Graves' disease, can cause thyroid gland enlargement that may:

  • Compress laryngeal structures
  • Affect recurrent laryngeal nerve function
  • Create mechanical pressure on the trachea 2

• Associated autoimmune processes: Autoimmune thyroid disorders like Graves' disease may involve inflammatory processes that affect the larynx 3

Clinical Presentation

Patients with hyperthyroidism-related laryngitis may present with:

• Hoarseness
• Voice fatigue
• Decreased vocal range
• Throat discomfort
• Globus pharyngeus (sensation of a lump in the throat) 2

Diagnosis

1. Thyroid function tests:

   • TSH level (typically suppressed <0.45 mUI/L in hyperthyroidism)
   • Free T4 and T3 levels (typically elevated) 4

2. Laryngeal examination:

   • Laryngoscopy to assess vocal fold mobility and laryngeal structures
   • Look for signs of inflammation, edema, or other changes 2

3. Additional testing when indicated:

   • Thyroid ultrasound to assess gland size and nodules
   • Radioactive iodine uptake scan to determine etiology of hyperthyroidism 4, 5

Management

Primary Treatment of Hyperthyroidism

Treatment of the underlying hyperthyroidism is essential for resolving associated laryngitis. Options include:

1. Antithyroid medications (methimazole, propylthiouracil)
2. Radioactive iodine ablation
3. Thyroidectomy - particularly when a goiter is causing compressive symptoms affecting the voice 6, 5

Symptomatic Management of Laryngitis

While treating the underlying thyroid disorder:

• Voice rest to reduce laryngeal irritation
• Adequate hydration to maintain mucosal health
• Avoid irritants such as smoking and alcohol
• Voice therapy may be beneficial for persistent voice changes 2

Post-Thyroidectomy Voice Care

For patients requiring thyroidectomy:

• Monitor for recurrent laryngeal nerve injury - occurs in 0.85% to 8.5% of cases
• Early otolaryngology referral for voice changes post-surgery
• Speech therapy for persistent voice problems 2

Special Considerations

Voice Professionals

Individuals who rely on their voice professionally require special attention:

• Earlier intervention may be warranted
• More aggressive management of voice symptoms
• Close coordination between endocrinology and otolaryngology 2

Medications That May Worsen Symptoms

Be aware of medications that can exacerbate voice problems:

• Inhaled steroids
• Antihistamines
• Anticholinergics
• Diuretics 2

Prognosis

Voice changes related to hyperthyroidism typically improve with successful treatment of the thyroid disorder. However, if structural changes have occurred in the larynx or if nerve damage is present (particularly after thyroid surgery), some voice changes may persist and require specific voice therapy or laryngeal procedures 2.

Common Pitfalls

• Misattribution: Not recognizing the connection between thyroid dysfunction and voice changes
• Delayed diagnosis: Treating laryngitis symptomatically without investigating thyroid function
• Inappropriate treatment: Using antibiotics for non-infectious laryngitis associated with hyperthyroidism 2
• Overlooking post-surgical voice changes: Failing to monitor for recurrent laryngeal nerve injury after thyroid surgery 2