An elderly man complains of feeling cold all the time, even though the weather is warm. There is no evidence of anemia on a complete blood count; thyroid studies are normal. What additional studies should be ordered? — Felix N. Chien, DO, Newport Beach, Calif.

Cold intolerance is difficult to define and may refer to either local or systemic symptoms that can be acute or chronic. Hypothyroidism is the most well-known etiology, but there are many causes and the history and physical exam are crucial to direct further testing. For example, acute localized symptoms (such as in the hand) can imply vascular injury, and this should be ruled out.

A history of recent trauma, clotting disorders, and focal neurologic symptoms and signs may provide important clues. Prior neuromuscular damage may lead to focal but chronic symptoms such as with postpolio syndrome. Similarly, post-traumatic cold intolerance can last for years after injury.

Acute systemic cold intolerance, especially if accompanied by orthostasis, nausea, fatigue, or fever, could be the result of adrenal insufficiency or sepsis, and both should be considered. Chronic systemic symptoms can result from low body weight (as with anorexia nervosa or chronic illness) or advanced peripheral vascular disease. Depression, fibromyalgia, and sleep deprivation have also been associated with cold intolerance. — Daniel G. Tobin, MD (157-6)