Thrombocytopenia in Malaria- a retrospective study

Abstract

Introduction: Malaria is usually associated with low blood cell counts and mild to moderate thrombocytopenia is a common association. The cause of thrombocytopenia is poorly understood, but the immune-mediated lysis, sequestration in the spleen and diminished platelet production by the bone marrow have all been postulated.

Objectives: This study was carried out to evaluate the degree of thrombocytopenia in patients suffering from malaria.

Methods: This retrospective cross-sectional analytical study was conducted at Armed Forces Institute of Pathology (AFIP), over a period of one-year from January 2012 to December 2012. A total 81 cases of malaria parasite positive on peripheral blood film were studied by full blood counts (FBC) with automated haematology analyzer Sysmex 1800i. Thick and thin smears were stained with Giemsa and Leishman stains and examined by haematologist. Data was analyzed using the SPSS version 10.0.

Results: Out of 81 patients, all were male. Mean age was 24.3 years (Mean+2SD:24.3±10.7) with a range of 23-42 years. Plasmodium falciparum was detected in 61(75.3%) cases, P. vivax in 16 (19.8%) and mixed infection in 04 (4.9%) cases. Haemoglobin values in patients of malaria with thrombocytopenia and without thrombocytopenia were 10.8±3.2 g/dl and 12.2±2.6 g/dl respectively. White blood cell counts in patients with and without thrombocytopenia were 6.2±4.3X10⁹/L and 9.3±5.2X10⁹/L respectively. 25 JAFMC Bangladesh. Vol 10, No 1 (June) 2014 Out of 81 patients, 23 (28.4%) had normal platelet counts, and 58 (71.6%) had thrombocytopenia. Platelet counts in patients with malaria with and without thrombocytopenia were 48.1±25.3X10⁹/L and 199±45.4X10⁹ respectively. The mild, moderate and severe thrombocytopenia were found in 44 (75.9%), 09 (15.5%) and 05 (8.6%) cases respectively. Platelet counts of <20X10⁹/L were noted in only 8.6% cases of falciparum malaria and none in vivax malaria.

Conclusion: The study found high frequency of mild to moderate thrombocytopenia in the Plasmodium falciparum and plasmodium vivax malaria. Although thrombocytopenia is uncommon in malaria, its presence is not a distinguishing feature between the two types. Finding of thrombocytopenia in a patient with fever is of diagnostic help as it raises the suspicion of malaria. Thrombocytopenia of <20X10⁹/L can occur in P. vivax malaria although it is statistically more common with P. falciparum malaria. The above findings can have therapeutic implications in context of avoiding unnecessary platelet infusions with the relatively benign course in P. vivax malaria.

DOI: http://dx.doi.org/10.3329/jafmc.v10i1.22899

Journal of Armed Forces Medical College Bangladesh Vol.10(1) 2014