The hyper-reactive malarial splenomegaly

Q: The hallmark of hyper-reactive malarial splenomegaly (HMS) is the high level of Peripheral parasitemia, diagnosed by peripheral blood slide.

A) True

B) False

Answer: B

Hyper-reactive malarial splenomegaly, also known as tropical splenomegaly syndrome, is a complication of chronic malaria. Due to long term chronic infection, peripheral parasitemia is usually absent. The diagnosis is based on combination of clinical, epidemiological, hematological, and immunological findings, like it is more common in eastern Indonesia and the Papuan highlands.

Immunologically, there is an overproduction of IgM due to repeated infection, with formation of immune complexes that cause prolonged stimulation of splenic reticuloendothelial cells. There may be a a decrease in T-suppressor lymphocytes that normally downregulate B-lymphocyte function and antibody production.

Clinically, it causes massive splenomegaly, left upper quadrant pain, fatigue, ascites, lower extremity edema, and dyspnea.

Treatment is chloroquine 300 mg base as 500 mg salt once weekly (or alternate regimen) till clinical and immunological signs resolved. Splenectomy is not recommended unless it is life threatening or there is a failure of medical treatment as mortality is very high.

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References:

1. Moraes MF, Soares M, Arroz MJ, et al. [New concepts in hyperactive malarial splenomegaly]. Acta Med Port 2003; 16:41.

2. Leoni S, Buonfrate D, Angheben A, et al. The hyper-reactive malarial splenomegaly: a systematic review of the literature. Malar J 2015; 14:185.

3. Mothe B, Lopez-Contreras J, Torres OH, et al. A case of hyper-reactive malarial splenomegaly. The role of rapid antigen-detecting and PCR-based tests. Infection 2008; 36:167.