Hemostatic disorders and their implication in the pathogenesis of Astrakhan rickettsial fever

AIM: to define a role of hemostatic disorders in the pathogenesis of Astrakhan rickettsial fever (ARL). SUBJECTS AND METHODS: Platelet functional activity and plasma hemostatic parameters were studied in 89 patients of moderate ARL. RESULTS: The clinical manifestations of hemostatic disorders at the height of ARL were characterized by the appearance of typhoid maculopapular rashes in 91.4% of the patients, solitary elements of which were transformed to petechiae in 20% of cases. At convalescence (on day 10.2 +/- 1.3 of the disease), all eruptions regressed via pigmentation. At the peak of the fever, there were nasal hemorrhages and bleedings from the sites of injections; lowered platelet aggregation was detectable in the presence of thrombocytopenia at the height. Coagulation hemostasis changes were characterized only by elevated fibrinogen levels. Increased platelet functional activity and decreased fibrinogen concentrations were observed at convalescence. CONCLUSION: The basis of the clinical manifestations of ARL is hemostatic disorders due to thrombocytopenia and diminished platelet functional activity. In early convalescence, there was improved platelet aggregatability; however, the increasing trend for the rate of aggregation and the radius of aggregates suggests a risk of thrombogenesis in convalescents, which requires their follow-up with obligatory hemostatic monitoring.