Cat-scratch disease

WILLIAMSBURG, VA. -- Keep cat scratch disease in mind for patients with prolonged fevers of unknown origin.

Bartonella is "absolutely the most common cause we recognize in fever of unknown origin," Dr. Sheldon L. Kaplan said at a meeting on practical pediatrics sponsored by the American Academy of Pediatrics.

Physicians have discovered a new systemic form: hepatosplenic cat scratch disease. In 19 cases of hepatosplenic cat scratch disease seen at Texas Children's Hospital in Houston, the most common patient complaint was fever. "These kids had fevers on a daily basis for 3 weeks be fore the diagnosis was established" and were given a whole host of antibiotics be fore presenting to the hospital, said Dr. Kaplan, chief of the infectious disease service at the institution.

Some patients' fevers had resolved with previous courses of antibiotics, but others hadn't. Most of the fevers subsided within 5 days of the children being diagnosed and started on rifampin, Dr. Kaplan reported.

All of the children had a history of con tact with cats or kittens. Other clues included abdominal pain during examination and a palpable enlarged spleen or tender liver. The median age of the patients was 5.5 years.

Only five of the patients (26%) had lym phadenopathy and only two (11%) bore scratch marks. None had the classic papule of cat scratch disease. Researchers stumbled upon this particular manifestation during 1988 in children with prolonged fever and granulomas in the liver, Dr. Kaplan said. "Subsequently, we're all convinced of the possibility of hepatosplenic cat scratch in the correct setting."

Systemic presentation of the usually benign, self-limiting infection is rare, but should be considered in children with prolonged fever, abdominal pain, and elevated erythrocyte sedimentation rate, he said.

The tentative diagnosis can be substantiated with radiographs or CT scans showing microabscesses in the liver, spleen, or both organs.

Dr. Kaplan said he sends serology samples to the Centers for Disease Control and Prevention, which provides information on their Bartonella diagnostic services at 404-639-1075.

Although laboratory assays are useful for confirmation, they are not diagnostic in the sense that treatment should not hinge on results that can take 3 weeks to return, Dr. Jamie Childs, chief of the CDC branch of viral and rickettsial diseases, Atlanta, noted in a later interview.

There is no standard definition for fever of unknown origin in children. Dr. Kaplan uses the label for any fever over 38 degrees Celsius going unexplained for 2-3 weeks in spite of a careful physical examination and laboratory assessment.

Infectious diseases tend to bear the brunt of the blame for mystery fevers. A study of 64 children with fever of unknown origin resulted in diagnoses of Epstein-Barr virus in 16, osteomyelitis in 12, and bartonellosis and urinary tract infection in 5 children each. The other diagnoses included cytomegalovirus, tularemia, ehrlichiosis, blastomycosis, and enterovirus infection.

Of course, many cases of fever of unknown origin remain unsolved. In another study, 73 of 109 children with fever of unknown origin were never diagnosed with a particular disease despite receiving a barrage of tests and more than their share of poking and prodding.

"There are a fair number of viruses that we haven't described yet. Obviously, there are a lot of things going on that we don't understand," Dr. Kaplan said.

COPYRIGHT 2001 International Medical News Group
COPYRIGHT 2001 Gale Group