Thyrotropin

What Is Hypothyroidism?

Author/s: 
Krista Roberts

Hypothyroidism is a disease of thyroid hormone deficiency.

The most common cause of hypothyroidism worldwide is insufficient intake of iodine, a mineral found in iodized salt and some foods (such as seafood and dairy) that is needed for production of thyroid hormones. In the US and other high-income countries, the most common cause of hypothyroidism is an autoimmune condition called Hashimoto thyroiditis.1

Tilt Table Testing

Author/s: 
Chesire, W.P., Dudenkov, D.V., Munipalli, B.

A 43-year-old woman presented with a 1-year history of recurring symptoms of sudden onset of fatigue, palpitations, dyspnea, chest pain, lightheadedness, and nausea that were associated with standing and resolved with sitting. These symptoms began 1 month after mild COVID-19 infection. At presentation, while supine, blood pressure (BP) was 123/70 mm Hg and heart rate (HR) was 90/min; while seated, BP was 120/80 and HR was 93/min; after standing for 1 minute, BP was 124/80 and HR was 119/min. Physical examination results were normal. Oxygen saturation was 98% at rest while breathing room air. She had no oxygen desaturation during a 6-minute walk test but walked only 282 m (45% predicted). Complete blood cell count, morning cortisol, and thyrotropin blood levels were normal. Electrocardiogram (ECG), chest computed tomography, pulmonary function testing, methacholine challenge, bronchoscopy, echocardiography, and cardiac catheterization findings were normal. During tilt table testing, the patient experienced lightheadedness and nausea when moved from horizontal to the upright position. Results of the tilt table test are shown in the Table and Figure.

Tilt Table Testing

Author/s: 
Chesire, W.P., Dudenkov, D.V., Munipalli, B.

A 43-year-old woman presented with a 1-year history of recurring symptoms of sudden onset of fatigue, palpitations, dyspnea, chest pain, lightheadedness, and nausea that were associated with standing and resolved with sitting. These symptoms began 1 month after mild COVID-19 infection. At presentation, while supine, blood pressure (BP) was 123/70 mm Hg and heart rate (HR) was 90/min; while seated, BP was 120/80 and HR was 93/min; after standing for 1 minute, BP was 124/80 and HR was 119/min. Physical examination results were normal. Oxygen saturation was 98% at rest while breathing room air. She had no oxygen desaturation during a 6-minute walk test but walked only 282 m (45% predicted). Complete blood cell count, morning cortisol, and thyrotropin blood levels were normal. Electrocardiogram (ECG), chest computed tomography, pulmonary function testing, methacholine challenge, bronchoscopy, echocardiography, and cardiac catheterization findings were normal. During tilt table testing, the patient experienced lightheadedness and nausea when moved from horizontal to the upright position. Results of the tilt table test are shown in the Table and Figure.

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