
Background: Thrombocytopenia is not a disease but a symptom. For investigating causes of thrombocytopenia in patients, the aetiology can be achieved by taking a good clinical history, physical examination and basic laboratory tests. Thrombocytopenia has an inverse relation to mortality and morbidity is various febrile illnesses, serial monitoring of platelet counts has prognostic value. This highlights the importance of thrombocytopenia in various febrile disorders. Objective: To assess etiological factors of thrombocytopenia in acute febrile illness in indoor patients in our hospital. To assess the prognosis of acute febrile illness in relation with severity of thrombocytopenia. To correlate platelet count with bleeding and effectiveness of platelet replacement therapy. To assess the complications and mortality in relation to thrombocytopenia. Materials and Methods: The study is a observational randomised case study carried out from January 2016 to September 2017 at C.U. Shah Medical College and Hospital, Surendranagar (Gujarat). Hundred patients of acute febrile illness admitted to the medicine Department with platelet count less than 1,50,000 per microliter of blood with evidence of infection. The study protocol was approved by the institutional research review board and ethical committee. Result: Maximum number of patients were in age group 31 to 40 years (27%) and Male predominance was observed in all the age groups. Out of 100 patients, Maximum number of 81 (81%) patients presented within 7 days with complain of fever.21 patients had some kind of bleeding manifestation. Hematuria was the most common bleeding manifestation. 14 (14%) number of patients had very severe thrombocytopenia, 55 (55%) number of patients had severe thrombocytopenia, 29(29%) number of patients had moderate thrombocytopenia and 2(2%) patients had platelet count between 1,00,000-1,50,000/ml on presentation. Out of 100 patients 2 were expired and 98 patients were discharged. Anemia was the most common complication other than bleeding. Conclusion: Febrile illness accounts for large number of cases with thrombocytopenia. Most common cause of thrombocytopenia in patients presented with acute febrile illness was Malaria in 55 patiens, among them 40 patients had P. vivax and 15 patients had P. falciparum followed by dengue fever (22%). Anemia (36%) was the most common sequelae other than bleeding manifestation and Hematuria (9%) was the most common bleeding manifestation. Thrombocytopenia has an inverse relation to mortality and morbidity is various febrile illnesses, serial monitoring of platelet counts has prognostic value. This highlights the importance of thrombocytopenia in various febrile disorders.