He had blood in his urine and a strange rash. What was happening?

A rash of small crusts

Fishman listened to the young man’s story and then examined it. The bump on his neck was obvious. She had seen him from the doorway. But it wasn’t tender and moved easily, like lymph nodes are supposed to. The rash was also easily visible, but on her arms she noticed something different. “What is this?” she asked, pointing to spots that looked like tiny scabs. It’s from my cats, replied the patient. They had four at home. They liked to play and sometimes left traces.

After the exam, Fishman excused herself and went to find the primary resident she was working with, Dr. Neeharika Namineni. The resident had also seen the patient and reviewed his records. Fishman described what she found and reviewed the emergency department test results. His thyroid was normal. He had no antibodies to Lyme or the other tick-borne diseases commonly seen in the Northeast, anaplasmosis and babesiosis. He had no antibodies against HIV. Fishman paused. Yet he could have HIV at an early stage, before the antibodies are present. It takes four to six weeks to develop a measurable number of antibodies against most infections. Additionally, an acute HIV infection may begin with fever and a rash. So first she would like to send a test to look for HIV itself, to make sure it was not in the early stages of this infection. He also had those cat scratches. Could it be cat scratch fever or toxoplasmosis? Each of these diseases can be transmitted from cats to humans through scratches; each can cause febrile illness and enlarged lymph nodes. Finally, could this be evidence of a hidden cancer – possibly testicular cancer – that has spread to his lymph nodes?

Namineni thought infection was more likely, but cancer was definitely possible. Fishman has added tests for these pathogens to their orders. If all the tests were negative, they would be looking for cancer.

The next morning they met with the patient’s supervisor, Dr. Lloyd Friedman. Again, Fishman described the patient and her thoughts. Friedman’s eyes lit up when the young woman mentioned the cat scratches. “I’m betting on cat-scratch fever,” he enthused after she finished her presentation. Friedman wondered aloud if this infection could cause ITP. A quick internet search turned up only one case report. So it was rare but still possible. Friedman doubled down. The scratches, the fever, the extremely swollen lymph node: it sounded like cat-scratch fever to him.

The patient received several doses of intravenous immunoglobulin over the following days. He did his job – his platelet count started to return to normal, going from 2 to 6 to 15 to 30 to 60. The patient hadn’t felt sick since arriving at the hospital, and the blood in his urine and the sores in his mouth cleared up after the first dose of immunoglobulin.

With his platelet count improving – although still far from normal – the patient was safe (and eager) to leave the hospital. Even after he left, Fishman monitored the labs for results. It wasn’t toxoplasmosis. It wasn’t acute HIV. Finally, they got their answer: he had cat-scratch fever, an infection caused by bacteria called Bartonella henselae. By this time, the patient’s symptoms had long disappeared. Even the swollen lymph node was barely visible.