Carpal Tunnel Syndrome in Persons with Acromegaly

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The summary below is from the full report titled "The Pathology of Median Neuropathy in Acromegaly." It is in the 1 August 2000 issue of Annals of Internal Medicine (volume 133, pages 197-201). The authors are P.J. Jenkins, S.A. Sohaib, S. Akker, R.R. Phillips, K. Spillane, J.A.H. Wass, J.P. Monson, A.B. Grossman, G.M. Besser, and R.H. Reznek.

What is the problem and what is known about it so far?

Acromegaly is a rare disease in which high levels of growth hormone lead to increases in the size of the hands, feet, and head, as well as changes in internal organs and the skin. Growth hormone, which comes from a gland called the pituitary (located under the brain), controls growth in children and regulates the way the body uses fats and carbohydrates in adults. Adults with acromegaly are known to be at risk for a condition known as the carpal tunnel syndrome. In this syndrome, parts of the hand become painful, numb, and weak because of pressure on the median nerve, one of the nerves that travel through the carpal tunnel. (The carpal tunnel is a small opening deep inside the wrist.) It is not known whether acromegaly leads to the carpal tunnel syndrome because the soft tissues in the carpal tunnel swell and compress the median nerve (which seems to be the case in patients without acromegaly who develop the carpal tunnel syndrome), or because the nerve itself swells.

Why did the researchers do this particular study?

To understand better why patients with acromegaly develop the carpal tunnel syndrome.

Who was studied?

The researchers studied nine patients with acromegaly, four of whom had symptoms of carpal tunnel syndrome (discomfort, numbness, or weakness of the hand).

How was the study done?

The researchers used magnetic resonance imaging (MRI) to take pictures of the inside of the patients' wrists, both at the time they entered the study and again after 6 months of treatment for acromegaly. These pictures made it possible to measure changes in the nerves and soft tissues in the carpal tunnel.

What did the researchers find?

The size of the median nerve was increased in patients with the carpal tunnel syndrome compared with patients without symptoms of the syndrome, suggesting that the nerve itself was swollen. The soft tissues around the nerve were the same size in patients with and those without symptoms. In patients who had carpal tunnel syndrome symptoms, the median nerve enlargement decreased after the patients received treatment for acromegaly.

What were the limitations of the study?

The study included only nine patients, so it is uncertain whether the findings would apply to all patients with acromegaly and the carpal tunnel syndrome.

What are the implications of the study?

The carpal tunnel syndrome in patients with acromegaly appears to be related to swelling of the nerve itself rather than to enlarged soft tissues in the carpal tunnel pressing on the nerve.