Happy Friday, Moffitt!
Thank you to Sarah L. for sharing an amazing case of a young man with CVID on IVIG and Cronh’s disease on infliximab who recently traveled to Mexico, presenting with several days of fevers, HA, and thrombocytopenia. We don’t yet have a final diagnosis, but have a high suspicion for dengue! See below for pearls about fever in a returning traveler and then a little more about dengue and chikungunya. BONUS: I also attached the Nature Immunology Review about immunodeficiency and autoimmunity that we discussed this AM.
❤ TLC (Tim and Laura, your Chiefs)
Approach to fever in a returning traveler
- First, acknowledge that the patient can have a fever related to their travel vs. independent of it. For travel independent fevers, consider the usual categories: infectious vs. non-infectious (malignancy, rheumatologic, meds/tox, etc). Also don’t forget that fever in a returned travel is often caused by common, cosmopolitan infections such as PNA and pyelo, so don’t forget about these in search for an exotic diagnosis.
- When considering travel-related fevers, think about geography and incubation period to narrow the differential diagnosis.
- Travel history (destination, urban/rural, vaccinations and malaria prophylaxis)
- Exposures (animals, bites, water, diet, tattoos, sexual contact)
- Timing (incubation period)
- Differential Diagnosis for Incubation Period <21d:
- Bacterial: Typhoid, nontypohoidal salmonellosis, leptospirosis, rickettsial diseases, meningoccemia
- Viral: Zika, dengue, chikungunya, EBV (mononucleosis), WNV, Japanese encephalitis, yellow fever
- Parasitic: Malaria
- Differential Diagnosis for Incubation Period >21d:
- Bacterial: Brucellosis
- Viral: Viral hepatitis (especially HepA and HepE), acute HIV, rabies
- Parasitic: Leishmaniosis
- Fungal: Endemic fungi (check prevalence by region)
- Mycobacterial: Tuberculosis
- Fun Facts
- Malaria is the most common cause of acute undifferentiated fever after travel to sub-Saharan Africa and some other tropical areas, per the CDC.
- Dengue is the most common cause of febrile illness among people who seek medical care after travel to Latin America or Asia, per the CDC.
- Geosentinel: http://www.istm.org/geosentinel A Global Surveillance Network of the International Society of Travel Medicine in Partnership with the CDC. The resource Harry mentioned today!
- NEJM 2017: The article Dan referred to about an approach to fever in a returning traveler, attached and here: https://www.nejm.org/doi/full/10.1056/NEJMra1508435
- CDC Post-Travel Evaluation: https://wwwnc.cdc.gov/travel/yellowbook/2018/post-travel-evaluation/fever-in-returned-travelers#5017
- Table 5-02: Common causes of fever by geographic area
- Table 5-03: Common infections by incubation period
- Table 5-04: Common clinic findings and associated infections
Dengue vs. Chikungunya
- Febrile illness caused by infection with one of four dengue viruses (DENV) which is transmitted by the Adedes aegypti or Aedes albopictus
- Infections may be asymptomatic or present with a broad range of clinical manifestations including a mild febrile illness to dengue hemorrhagic fever to life-threatening shock.
- Incubation period is 4-7 days
- Febrile illness caused by infection with the chikungunya virus which is also transmitted by Adedes aegypti or Aedes albopictus
- The name chikungunya is derived from the Kimakonde language spoken in Tanzania meaning “that which bends up” or “stooped walk” because of the incapacitating arthralgia caused by the disease. Mortality is rare and usually occurs in older adults
- Incubation period is 3-7 days, but can cause relapsing or persistent symptoms of rheumatologic symptoms (up to a year in many cases!).
Which one is which??
- As Harry said this morning, it is very difficult to distinguish dengue and chikungunya clinically, so you usually need lab testing. In general, if the patient has thrombocytopenia, think more about dengue. If arthralgia/myalgia is the predominant feature, think more about chikungunya. See this table from the CDC for a general comparison and this recent NEJM CPS case for more info!