White blood cell drop leads to infections

Dear Dr. Donohue • What is leukopenia? My brother, age 67, has it. — R.B.

Answer — The definition of leukopenia (LUKE-uh-PEA-nee-uh) is a drop in the number (“penia”) of white (“leuko”) blood cells. White blood cells protect us from foreign invaders, like bacteria and viruses. Five different kinds of white blood cells exist, each with its own function. The most numerous variety is granulocytes, also called neutrophils.

“Leukopenia” often is used to indicate a deficiency of granulocytes. They’re the attack dogs of white blood cells. Infections are inevitable with too few of them.

Umpteen conditions lead to a shortage of these cells. A condition called cyclic leukopenia consists of three-to-five-day periods when the count drops and then rebounds. During the dropoff, people can become quite sick. Rheumatoid arthritis and lupus deplete the white-blood-cell count. So does an overactive thyroid gland. Acute leukemia — white blood cell cancer — often features a low count in its early stages. Deficiencies of vitamin B-12 and folate (another B vitamin) can bring down the count.

An enlarged spleen is another cause. The point is that it takes a fairly long time and a complicated investigation to come up with the cause of leukopenia. Treatment, of course, depends on finding the exact cause.

An innocuous cause of a low white count is chronic idiopathic leukopenia of adults. Here, no cause for the dropoff in white blood cells is found, but this condition is something that happens without rhyme or reason and without dire consequences.

Your brother must have undergone many tests, and should be prepared for many more.

He might need to have a sample of bone marrow removed to discover the correct diagnosis.

Write Dr. Donohue at P.O. Box 536475, Orlando, Fla. 32853-6475.