Malaria Headphone

Long time ago, in a teaching hospital far, far away

A fifty-four-year-old man came to the emergency department with fever, chills, headache, and profound fatigue.

He had just returned from a trip to Vietnam.

By the time I arrived, one of my medical students had already seen him.

"So," I asked, "what do you think?"

"Well, he has a fever after travel, so I thought about malaria.

But he took malaria prophylaxis."

"So?" Jennifer looked at me.

"Well, doesn't that make malaria unlikely?"

"Less likely," I said.

"Not impossible." And that distinction between less likely and impossible is one of the most important distinctions in medicine.

Malaria prophylaxis is not a force field.

It reduces the risk of malaria considerably, but no prophylactic regimen provides one hundred percent protection.

Patients can miss doses.

Absorption may be imperfect.

The medication may not match the local resistance pattern, and some malaria species can leave dormant forms hiding in the liver, waiting for another day.

So when a patient comes back from a malaria-endemic region with fever, the sentence, "But he took prophylaxis," should lower malaria on your differential.

It should never erase it.