From the Guidelines
Cough in thyroid disorders is often associated with hypothyroidism, and treating the underlying condition can resolve cough symptoms. According to a study published in Chest in 2006 1, patients with idiopathic chronic cough are eight times more likely to have an organ-specific autoimmune disease, particularly hypothyroidism. This suggests a link between thyroid disorders and cough, potentially due to lymphocytic airway inflammation or an autoimmune process in the respiratory system.
Causes of Cough in Thyroid Disorders
- Hypothyroidism: may cause cough due to fluid retention in the airways or decreased clearance of mucus
- Hyperthyroidism: can lead to cough through increased respiratory rate or associated autoimmune conditions
- Thyroiditis: can cause cough due to a local irritative effect of the inflamed thyroid
- Tracheomalacia, extrinsic compression by goiter, and/or tracheal ingrowth by thyroid malignancy: may cause cough due to upper airway obstruction
Treatment of Cough in Thyroid Disorders
- Treating the underlying thyroid condition is essential, as it can often resolve cough symptoms
- For hypothyroidism, levothyroxine (typically starting at 25-50 mcg daily, adjusted based on TSH levels) may be effective in resolving cough symptoms
- For hyperthyroidism, medications like methimazole (starting at 10-30 mg daily) or propylthiazil may help
- Symptomatic management with cough suppressants like dextromethorphan (15-30 mg every 6-8 hours) can provide temporary relief
- Staying hydrated and using a humidifier may also help ease symptoms, as suggested by the study 1 that highlights the importance of treating the underlying condition to resolve cough symptoms.
From the Research
Cough in Thyroid Disorders
- Cough can be a presenting complaint of thyroiditis, as reported in a 1982 study 2, where two patients with non-conventional thyroiditis had chronic persistent cough as their chief complaint.
- Thyroid disease, including hypothyroidism and hyperthyroidism, can have various symptoms, but cough is not typically highlighted as a common symptom in general reviews of thyroid disease management 3, 4.
- However, a 2023 case report 5 describes a patient with papillary thyroid carcinoma presenting with chronic cough and hemoptysis, suggesting that thyroid disorders can occasionally manifest with respiratory symptoms.
- A systematic review of respiratory manifestations of hypothyroidism 6 found that hypothyroidism is associated with increased pulmonary morbidity and mortality, but the evidence for a direct effect on pulmonary function is ambiguous, and more research is needed to understand the relationship between hypothyroidism and respiratory problems.
Possible Mechanisms
- The systematic review 6 identified possible mechanisms explaining respiratory problems in hypothyroidism, including:
- Ventilator control system dysfunction
- Diaphragmatic muscle function impairment
- Pulmonary gas exchange abnormalities
- Goiter-caused upper airway obstruction
- Decreased capacity for energy transduction
- Reduced glycolytic activity
- Obstructive sleep apnea syndrome was found to be common among patients with overt hypothyroidism, and was reversible with treatment 6.