Tropical Medicine in the ER
No matter where you practice emergency medicine, there’s a good chance you’ll need to know a little tropical medicine. Luckily, the vast majority of febrile illnesses in returning travelers from tropical climates are actually due to a fairly small number of conditions. In fact, approximately 90% of the cases of tropical illnesses can be attributed to malaria, dengue, enteric infection, rickettsial infection, chikungunya, and Zika.
“The most important step in diagnosing and treating a tropical illness is to consider it. If you don’t think about it, you can’t diagnose it. You must get in the habit of asking a travel history in every patient presenting with fever. If you don’t ask, you don’t know to suspect these conditions and you’re sure to miss it. ”
I recently gave a lecture during conference entitled, “5 Tropical Infections All Emergency Physicians Should Know.” I’ve included the link to my lecture for those of you interested in learning more. My lecture reviews 5 diseases worth knowing about. For the remainder of this post, let’s review the condition that was number #1 on my list: Malaria.
#1 Malaria
“Malaria is a can’t miss diagnosis and as Emergency Providers, we are in the business of can’t misses. ”
When I was a medical resident my husband was working primarily in Nigeria. One day early on in my intern year I got a text from him in Nigeria asking me what to do for a fever. He was wondering if he should go ahead and start an antimalarial. At the time, I knew very little about malaria as a US medical resident. It was an eye opening moment for me and sparked an interest in global health. Around that same time, Dr. Erin Noste, had developed a Global Health curriculum at my residency and I was able to join that program which enabled me to complete a global health track and travel to Nigeria to see cases of malaria first hand.
One of the most important things I learned was that malaria presented with a very broad range of presentations. Its presentation was often flu-like in nature and depending on the patient it could mirror a minor viral illness or present with signs that more closely resembled severe sepsis with significant end organ damage and shock. Malaria even has the ability to present similar to meningitis in cases of cerebral malaria, which if not properly treated, end in death.
Malaria is the most common cause of fever in the returning traveler from tropical climates. Most cases of malaria in the US occur in travelers returning from Sub-Saharan Africa and Southeast Asia. Malaria can progress fairly rapidly and is associated with a significant risk of morbidity and mortality when not treated.
Bottom line: Consider Malaria in anyone who has been in a tropical climate now presenting with illness.
“A returning traveler with fever has malaria until proven otherwise. ”
What do you need to know about Malaria?
Transmission: Malaria is a parasitic disease transmitted from the Anopheles mosquito to human. Less commonly, transmission may occur through blood products, organ transplantation, placenta, and rarely needle sharing. Your patient and nurses are going to look to you as the physician to provide education regarding how this disease is transmitted. No special isolation is required. This is not contagious to others unless the infected person is donating blood or an organ.
Presentation: Malaria generally presents with fever, generalized malaise, and flu-like symptoms. There’s a wide spectrum of disease. Patients may have uncomplicated malaria with flu-like symptoms or complicated malaria (also known as severe malaria) which presents with signs of end organ damage. The physical exam of a patient with malaria may not be helpful but you may appreciate fever, hepatosplenomegaly, mild jaundice, tachypnea, and potentially altered mental status in cases of cerebral malaria. In general, rash is not a prominent feature of malaria which can suggest that the illness is more likely due to some other tropical infection such as dengue.
Highest risk groups: Immigrants who return to their native country to visit, pregnant, young children, and non-immune travelers. The majority of cases within the US fall within one of these high risk categories.
Incubation period: 7-30 days. The incubation period varies based on the species of malaria and the immunity of the host. The exception to this incubation period is vivax and ovale which can be dormant in the liver for a long time.
Other important facts: There are 5 species of malaria (falciparum, vivax, malariae, ovale, knowlesi). Falciparum is the most common and the most deadly. Vivax and ovale are notable because they can stay dormant in the liver and then cause a relapsing episode of malaria that can happen months to even a year later.
Diagnosis: You must send a thick and thin smear. 3 negative smears sent 12-24 hours apart are required to rule out malaria. The thick smear detects the presence of malaria, the thin smear detects the specific species involved.
Treatment & Disposition: Malaria can be classified as uncomplicated or complicated. Complicated can also be referred to as severe malaria. Many of the things that make malaria “severe” are common sense presentations such as shock, kidney failure, altered mental status, etc. For uncomplicated malaria, Artemisin Combination Therapy (ACT) is the first line treatment. An example is Coartem (Artemether Lumefantrine). If that’s not available at the pharmacy, check the CDC website and choose an alterative option based on the region and resistance pattern. For severe malaria, IV Artesunate is now FDA approved in the US! However, obtaining IV Artesunate requires a call to the CDC and flying the drug to your hospital. While awaiting arrival of IV artesunate, you could use treatments like quinidine gluconate or quinine sulfate.
I hope this has been a helpful review of malaria. For more about malaria and the 4 other conditions that made my list: Dengue, Chagas, Ebola, & Zika, check out my lecture. Remember to always consider malaria in the returning traveler and of course, don’t forget about the normal stuff too (UTIs, pneumonia, etc).
Featured Full Lecture
Special Thanks:
Dr. Adeline Dozois, Director of Global Health at Carolinas Medical Center and Dr. Erin Noste, Deputy Medical Director at Team Rubicon and UCSD EMS Fellowship Director, both took time to share their experiences and review the featured lecture.
References:
Gautret P, Parola P, Wilson ME. Fever in Returned Travelers. Travel Medicine. 2019;495-504. doi:10.1016/B978-0-323-54696-6.00056-2
•Am Fam Physician. 2003 Oct 1;68(7):1343-1350.
About the author
Dr. Okonkwo is the Assistant Program Director at USF Emergency Medicine. She completed medical school at Indiana University and did her Emergency Medcine residency at Carolinas Medical Center where she completed a Global Health Certificate.