Core EM - Emergency Medicine Podcast
Episode 167.0 – Malaria
An in depth review of this notorious parasite.
Hosts:
Brian Gilberti, MD
Audrey Bree Tse, MD
https://media.blubrry.com/coreem/content.blubrry.com/coreem/Malaria.mp3
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Tags: Infectious Diseases
Show Notes
Background
* In 2017, there were 219 million cases and 435,000 people deaths from malaria
* Five species: Falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.
* Falciparum, Vivax and Knowlesi can be fatal
* History of recent travel to Africa (69% of cases in US), particularly to west-Africa should raise suspicion for malaria
Clinical Manifestations
* Average incubation period for Falciparum is 12 days
* 95% will develop symptoms within 1 month
* Clinical findings with high likelihood ratios include periodic fevers, jaundice, splenomegaly, pallor.
* Can also have vomiting, headache, chills, abdominal pain, cough, and diarrhea
* Severe malaria has a mortality of 5% to 30%, even with therapy
* Diagnostic criteria for severe malaria:
Ashley 2018
* Most common manifestations of severe malaria affect the brain, lungs, and kidneys
* Patients with cerebral malaria can present encephalopathic or comatose, some severe enough to exhibit extensor posturing, or seizures
* Can have acute lung injury with a quarter of these patients progressing to ARDS
* Can have AKI from ATN and resultant acidosis
* Labs may be unremarkable but watch for anemia and thrombocytopenia
* Hgb <5 has an OR = 4.9 for death
* Severe thrombocytopenia has an OR = 2.8
* Anemia + Thrombocytopenia has an OR = 13.8 (Lampah 2015, PMID 25170106)
* Watch for hypoglycemia
* Be mindful of co-infection with salmonella and HIV
* Obtain BCx, cover with ceftriaxone
Diagnosis
* Blood smear
* Thick smear to increase sensitivity for detecting parasites
* Thin smear for quantifying parasitemia and species
* The first smear is positive in over 90% of cases, but if suspicion is high, it has to be repeated BID for 2-3 days for proper exclusion of malaria (CDC 2019)
Management
* For uncomplicated, non-severe cases, most patients with falciparum should be admitted, especially those with no prior exposure to malaria parasites
* Malarone is one of the first line options
* Check out other suggested regimens from the CDC
* Important to note that when they take this, ensure they take with milk or food containing fat to enhance absorption
* Severe Malaria