For decades he required varying doses of the steroid prednisone to keep the Crohn's from flaring up. But the long-term steroids had caused his bones to thin so that he had developed significant osteoporosis.
When a new type of drug came out that could control Crohn's and spare him from the steroids, he was eager to try it. He had received an intravenous dose of infliximab (or Remicade) every two months for the last year and had been doing well.
His doctor was hesitant when he told him of his plans to spend a month in sub-Saharan Africa on a hospital building project. "There are certain infections, like tuberculosis, that could spiral out of control if you get exposed to them on infliximab," he warned.
But the patient couldn't fathom letting his Crohn's keep him from his goals. He made an appointment with a travel clinic and planned to be very cautious on the trip. He had all the recommended shots and took his antimalaria pills without fail.
Three weeks after returning, as he lay miserable in the emergency room now with pain emerging in what seemed like every joint of his body, he feared maybe he had been too cavalier after all.
When the infectious diseases team came to see him, in addition to the joint pain, the patient had a high fever and a faint rash over his knuckles.
The patient talked to the team at length. No, he hadn't spent any time on the hospital children's ward. Or the tuberculosis ward. Yes, perhaps he had inhaled some dust and dirt while building. And he had used mosquito netting and had always taken his antimalarial pills. But he hadn't consumed any unbottled water, ice cubes, or uncooked vegetables. And he certainly had not had sex with prostitutes in Nairobi. Or elsewhere.
He did go to Lake Victoria for a long weekend and yes, he had waded in the water. His wife had called the other travelers and they were fine.
After returning, he had been doing great. His Crohn's had been quiet. He had received a dose of infliximab one week ago.
The patient underwent several blood tests, including a blood smear looking specifically for malaria and a blood culture to look for typhoid, two of the infections responsible for many of the cases of fever in travelers returning from sub-Saharan Africa. But the patient's symptoms were not really consistent with either of these.
From an infection point of view, the patient's report of wading in Lake Victoria was most intriguing, in particular for a parasitic infection called acute schistosomiasis or "Katayama fever," named for a Japanese town where the illness was described more than a century ago.
In many bodies of water in Africa and some parts of Asia, the Caribbean, and South America, the parasite eggs get into fresh water from human stool or urine. The parasite matures in species of snails until it emerges into the water. It then can penetrate human skin and enter the circulatory system, where it continues to mature to eventually look like a small worm.
The parasite migrates through the body to a final destination, often the veins feeding into the liver, where the worms begin to lay eggs.
It's during this migration that the body can react aggressively to the parasite, leading to fevers, muscle aches, and joint aches, not unlike the symptoms the patient experienced.
The treatment for schistosomiasis is a few doses of an antiparasitic drug that is quite safe. But with parasites dying throughout the body from the drug, the immune system can go wild and there is a risk a patient could get overwhelmingly ill, so that steroids are often given as part of Katayama fever treatment to quell the immune response.
The physicians sent off tests for schistosomiasis, cognizant that the results wouldn't be known for days and could be unreliable early in infection. The patient's basic blood work returned looking pretty normal - and without the high level of the type of white blood cells, called eosinophils, often seen in Katayama fever.
Without the eosinophils, while Katayama fever was not ruled out, the team also had to consider another, less exotic possibility: that the patient's symptoms had nothing to do with his travels at all.
Infliximab is a mouse-derived monoclonal antibody. The drug and others like it have dramatically altered the care of many diseases from Crohn's to rheumatoid arthritis, and while there are some potential issues that come up, most people don't have any major problems with the drugs.
But in rare cases, the immune system can react against the foreign proteins found in infliximab, causing a constellation of fevers, joint aches, and rashes known as "serum sickness." Classic serum sickness was seen when horse serum was used as treatment for diphtheria and scarlet fever.
In the patient's case, he got a dose of antiparasitic medication and steroids, and began to feel better. Apparently the improvement was due to the steroids - the schistosomiasis tests came back negative, including a repeat a month later.
The patient stopped the infliximab, with plans to begin an alternative drug without the same risk for serum sickness.
His a long-term plans include a return to Africa in five years, but next time, he'll skip the lakes.