- Thanks to Jen and Goop for pointing us towards this recent NEJM CPS case that also discussed ChikV vs Dengue!
- Malaria questions
- There was a question during morning report if check a blood smear for malaria is more likely to be positive when a patient is actually febrile. According to one of our UCSF malaria experts, there is no data that he is aware of regarding timing a blood smear to a period of fever. However, an interesting teaching point is that in endemic areas, patients with a documented fever are more likely to have malaria than those that report subjective fever.
- Interesting aside: an old reference suggested that you can use sub-cutaneous injections of epinephrine as a means of “provocation” for malaria testing. The idea was that this may contract the spleen to release parasites. In studies during the Vietnam war, this did not improve the sensitivity testing and actually was dangerous in patients with HTN. So don’t try this at home…
Take-home pearl: It can be difficult to distinguish chikungunya from dengue and you need lab testing. However, if arthralgia/myalgia is the predominant feature, think more about chikungunya. If the patient has thrombocytopenia, think more about dengue.
Additional info for Chikunguna vs Dengue
- Thanks to Billy and Jen for this paper from Singapore: PMID 23029573
- Patients with chikungunya had arthralgias and myalgias (statistically significant)
- Using platelets as a decision-point, a cut-off of platelets of 118K correctly classified patients into dengue 89% of the time
- Using platlets <100 plus clinical bleeding correctly classified patients into dengue 98% of the time
- Thanks to Jen Babik for this table from the CDC with the clinical characteristics to make the distinction