A 27 year old male presents with fever (of 40 degrees celsius), headache, vomiting, muscle aches and a diffuse erythematous, blanchable rash 1 week after travelling to India. 2 weeks later, his fevers have improved but the rash has changed characteristics and has not yet resolved.
What testing would you send to confirm your suspicion? Are you concerned about his rash?
This gentleman is presenting with Dengue Fever. The Dengue virus is an RNA Flavivirus that is carried by the Aedes mosquito (particularly A. Egypti). There are 4 subtypes. It is a significant global health concern affecting up to 100 million people annually in over 110 countries¹. It is considered a growing health threat – each year there are more cases found in a broader distribution of countries.
For patients presenting during the first week after fever onset, diagnostic testing should include a test for dengue virus (PCR) and Dengue Virus IgM¹. IgG antibodies are not useful for diagnostic testing because they remains detectable for life after a dengue infection. In addition, people infected with or vaccinated against other flaviviruses (such as yellow fever or Japanese encephalitis) may produce cross-reactive flavivirus antibodies, yielding false-positive serologic dengue diagnostic test results.
There are 3 different phases to the dengue infection: Febrile, critical and convalescent. However, about 75% of patients are asymptomatic!
The febrile phase lasts for 2-7 days and occurs after a 5-7 day incubation period. It is characterized by muscle aches, headache with retro-orbital pain, maculo or maculopapular rash, and minor hemorrhagic complications (e.g petechiae, purpura, ecchymosis).
The critical phase begins once the fevers end. Although most patients start to improve during this time, this is also where people can develop a systemic capillary leak system that can make them critically ill due to shock. Patients with dengue should be counselled to seek medical attention if they notice symptoms of ascites, pleural effusion or shock.
As the plasma leakage subsides, patients begin to resorb fluid that leaked out of capillary beds during the recovery or convalescent phase of the illness. There may be desquamation of the rash and associated pruritus.
For this patient, he presented with classic findings of the febrile phase. The progression of his rash is consistent with the recovery phase of the illness. The treatment of Dengue is just symptomatic, with NSAIDs and supportive care if hypotension or severe capillary leak syndrome is suspected.
Dengue, Zika and Chikengunya virus can all present with febrile illness
This article summarizes how you can differentiate between different febrile tropical diseases.
So how does this relate to our monthly theme of Women’s History Month?
Much of what we know about Dengue Virus is thanks to the contributions of Dr. Fe Del Mundo, a philipino peditrician who trained at Harvard medical school in the 1930’s. However, she was almost denied the opportunity to become a physician.
She was a brilliant student and had a personal sponsorship from the president of the Phillipines to study at any school in the world. When she chose Harvard Medical School, she didn’t realize that they had a policy at the time to not accept female medical students. When she showed up for the first day, mass confusion broke out! How could a woman practice medicine? Students and residents protested and the administrators tried to kick her out of the school but because her tuition had been sponsored and she had a powerful ally on her side, she was allowed into the school.
It wasn’t until 1945 that the first female medical student was officially allowed to enroll in the medical school, almost 100 years after it was first proposed.
Her career spanned an incredible 8 decades of productivity and she saw patients well into her 90s. She started her own children’s hospital in the Phillipines which runs to this day. Her graduate studies bacteriology and location in the tropics allowed her to focus on understanding the spread and pathophysiology of this emerging threat.
The history of women at Harvard is not mentioned in heavily advertised. If you don’t look for it, you would think that women simply did not want to go or meet the criteria to be admitted to medical school. However, we are indebted to physicians like Dr. del Mundo who paved the way forward.