Lung problems in thyroid diseases

Thyroid diseases can lead to various chest problems. Both hypothyroidism and hyperthyroidism can cause respiratory muscle weakness and decrease lung functions. 

Thyroid is a gland in neck which produces thyroxine hormone. Thyroid hormone is very important for good health. It drives protein, fat & carbohydrate metabolism of body. It maintains basal metabolic rate (BMR). So a less of thyroid hormones (hypothyroid) leads to decrease BMR and thus weight gain and more of thyroid hormone (hyperthyroid) in body causes weight loss. Thyroid hormone levels in body has  to be in the range. The hormone levels below or above the normal range causes various problems.

Changes in thyroid state during pregnancy can impair fetus growth and maturation. thyroid state can be assessed by thyroid function tests. A high TSH means hypothyroid  and low TSH means increase in thyroid hormones. 

There are certain respiratory problems encountered in thyroid dysfunction.

HYPOTHROIDISM & RESPIRATORY PROBLEMS:

• Causes obesity leading to Obesity Hypoventilation Syndrome
• Decreases respiratory drive from brain
• Causes respiratory and diaphragmatic muscle weakness
• cause obstructive sleep apnea 
• 1/4 th of hypothyroid patients have pleural effusion.

HYPERTHROIDISM & RESPIRATORY PROBLEMS:

•  Hyperthyroidism increases respiratory drive and cause breathlessness on exertion or rest
• Respiratory muscle weakness
• Grave's Hyperthyroidism (a subtype of hyperthyroidism) may be associated with allergy (raised IgE levels & atopic background) which can precipitate life threatening asthma attack on starting beta blocker medicine for hyperthyroidism
• Pulmonary Hypertension

ENLARGEMENT OF THYROID OR GOITER;

• Compression of trachea can occur with nodular goiters and thyroid cancers
• This leads to whistling sound on inhalation phase (stridor), breathlessness or cough

So, if you are a thyroid patient and you experience cough, breathlessness, snoring or daytime sleepiness, immediately contact your doctor.

Sleep apnea in Thyroid disorders (Hypothyroidism)

OSA is common in diseased thyroid state when thyroid secretes less hormone which is known as hypothyroidism. Hypothyroidism is when your thyroid is not secreting enough thyroid hormones and treated by oral thyroid tablets taken every day empty stomach. In hypothyroidism TSH levels are high and that is how it is diagnosed. OSA in hypothyroid state is independent of obesity and improves significantly with treatment of hypothyroid state.

So, OSA patients should undergo thyroid function tests to rule out Hypothyroidism. Similarly, in hypothyroid patients, OSA symptoms should actively be looked for and sleep study should be performed if required.