Platelet kinetics and scintigraphic imaging in thrombocytopenic malaria patients

Summary

Thrombocytopenia is a common occurrence in acute malaria. It is attributed, among other factors, to excessive splenic platelet pooling and a shortened platelet lifespan. The aim of our study was to evaluate the platelet kinetics and sequestration site by isotopic studies in uncomplicated malaria-induced thrombocytopenia. Seven thrombocytopenic malaria patients (74,000±36,000 platelets/µl) were included in the study. Autologous ¹¹¹In-labeled platelet scintigraphy was performed up to 96 hours (h) post injection (p.i.) to evaluate the platelet sequestration site. Late sequestration for the spleen (S) and the liver (L) was analyzed according to the following activity ratios: S (spleen count on the last day of the platelet lifespan / spleen count at 30 min) and L (liver count on the last day of the platelet lifespan / liver count at 30 min). Additionally, platelet survival studies were performed. A normal late sequestration (S: 0.95±0.06 and L: 1.04±0.08; normal values, S and L: 1 ± 0.2.) was observed in all of our patients. The platelet lifespan was reduced (1 to 4 days; normal range, 7-9 days), recovery was normal (mean, 63±6%; normal range, 55-75%), and the turnover rate was enhanced (mean, 95,000±80,000/µl/day; normal value, 35,000±4,500/µl/ day). According to the results of scintigraphy, the sequestration site by uncomplicated malaria-induced thrombocytopenia appears to be non-splenic and/or hepatic, yet diffuse.

Keywords

Malaria - thrombocytopenia - ¹¹¹In-oxine - platelets - sequestration

• References

• 1 Perrin LH, Mackey LJ, Miescher PA. The hematology of malaria in man. Semin Hematol 1982; 19: 70-82.
• 2 Wickramasinghe SN, Abdalla SH. Blood and bone marrow changes in malaria. Baillieres Best Pract Res Clin Haematol 2000; 13: 277-99.
• 3 Hill GJ, Knight V, Jeffrey GM. Thrombocytopenia in vivax malaria. Lancet 1964; I: 240.
• 4 Dennis LH, Eichelberger JW, Inman MM. et al. Depletion of coagulation factors in drugresistant Plasmodium falciparum malaria. Blood 1967; 29: 713-21.
• 5 Beale PJ, Cormack JD, Oldrey TB. Thrombocytopenia in malaria with immunoglobulin (IgM) changes. Br Med J 1972; 01: 345-49.
• 6 Horstmann RD, Dietrich M, Bienzle U. et al. Malaria induced thrombocytopenia. Blut 1981; 42: 157-64.
• 7 Borochovitz D, Crosley AL, Metz J. Disseminated intravascular coagulation with fatal haemorrhage in cerebral malaria. Br Med J 1970; 02: 710.
• 8 Fletcher JR, Butler T, Kopriva CJ. et al. Acute Plasmodium falciparum malaria: Vital capacity, blood gases, and coagulation. Arch Intern Med 1972; 129: 617-19.
• 9 Sheagren JN, Tobie JE, Fox LM. et al. Reticuloendothelial system phagocytic function in naturally acquired human malaria. J Lab Clin Med 1970; 75: 481-87.
• 10 Skudowitz RB, Katz J, Lurie A. et al. Mechanisms of thrombocytopenia in malignant tertian malaria. Br Med J 1973; 02: 515-18.
• 11 International Committee for Standardization in Hematology Panel on Diagnostic Applications of Radionuclides (ICSH). Recommended method for Indium-111 platelet survival studies. J Nucl Med 1988; 29: 564-66.
• 12 Heyns AP, Badenhorst PN, Wessels P. et al. Indium-111-labelled human platelets: a method for use in severe thrombocytopenia. Thromb Haemost 1984; 52: 226-29.
• 13 Lamy T, Moisan A, Dauriac C. et al. Splenectomy in idiopathic thrombocytopenic purpura: its correlation with the sequestration of autologous indium-111-labeled platelets. J Nucl Med 1993; 33: 182-86.
• 14 Oriuchi N, Korkmaz M, Kim EE. et al. Role of indium-111 labelled platelet scintigraphy in the management of thrombocytopenic patients with malignant neoplasms. Eur J Nucl Med 1988; 25: 247-52.
• 15 Thakur ML, Welch MJ, Joist JH. et al. Indium111-labeled platelets: studies on preparation and evaluation of in vitro and in vivo functions. Thromb Res 1976; 09: 345-57.
• 16 Lotter MG, Heyns AD, Badenhorst PN. et al. Evaluation of mathematic models to assess platelet kinetics. J Nucl Med 1986; 27: 1192-201.
• 17 Harker LA, Finch CA. Thrombokinetics in man. J Clin Invest 1969; 48: 963-74.
• 18 Neva FA, Sheagren JN, Shulman NR. et al. Malaria: Host-defence mechanisms and complications. Ann Intern Med 1970; 73: 295-306.
• 19 Russel PF, West LS, Mauwell RD. Practical malariology. In: London: Oxford University Press; 1963. 356 378.
• 20 Heyns AP, Badenhorst PN, Wessels P. et al. Indium-111-labelled human platelets: a method for use in severe thrombocytopenia. Thromb Haemost 1984; 52: 226-29.
• 21 Sodeman WA, Jeffrey GM. Primary malarial thrombocytopenia in the rhesus monkey. Trans R Soc Trop Med Hyg 1966; 60: 70.
• 22 Peters AM. Review of platelet labelling and kinetics. Nucl Med Commun 1988; 09: 803-8.
• 23 George JN, Woolf SH, Raskob GE. et al. Idiopathic thrombocytopenic purpura: a practice guideline developed by explicit methods for the American Society of Hematology. Blood 1996; 88: 3-40.