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