Carpal tunnel syndrome (CTS) is a common finding in patients with certain endocrine or metabolic problems. Hypothyroidism (low thyroid) and diabetes are the two most common conditions.

Anything that puts pressure on the median nerve as it goes through the carpal tunnel in the wrist can cause CTS. In the case of low thyroid, the thyroid gland isn't producing enough thyroid hormone. As a result, the tissues of the skin and connective fascia get separated by mucopolysaccharides (sugar) and proteins. The tendons get thick and stuck together putting pressure on the nerve.

In addition, water binds with the sugar-protein complex. Swelling occurs in places like the eyes, hands, and feet. This puts even more pressure on the nerve. Treatment of the thyroid condition usually takes care of the CTS symptoms.