Platelets and influenza A (N1H1)

Introduction: In January 2011 we had two pacients with Influenza A(H1N1) in our clinic and both of them had moderate thrombocytopenia. Therefore we decided to observe the abnormalities of thrombocytes during Influenza A(H1N1) pandemia. Materials and methods: Retrospective study based on medical records of 21 consecutive patients admitted in our clinic (November 2009- January 2010) for pandemic A(H1N1) and respiratory failure. Twelve patients had underlying diseases: obesity (6), diabetes mellitus (3), BPOC (2), asthma (1), HTA (1), TBC+SIDA (1). There were seven exitus (30%). Results: From 21 patients (11 female) nine (42,95%) patients had thrombocytopenia. In four of this nine cases (44.4%) thrombocytopenia was accompanied by low mean platelet volume (under 7 fL). The degree of thrombocytopenia was moderate (96000-110000/microL) and it was correlated significantly with the degree of inflammation measured by the serum C-reactive protein concentration. Also, all these patients had elevated levels of LDH and serum transaminases. Conclusions: Influenza A(H1N1) virus can induce a lower number of platelets. This virus can impair even platelets functions: in four cases thombocytopenia coupled with low mean platelet volum (MPV), elongated APTT and elevated levels of D-dimers, which can suggest an impact of Influenza A(H1N1) on coagulation. The platelet count can evaluate and monitor the efficiency of treatment: the thrombocytes count is the first parameter that returns to its normal levels in cases with a good evolution. The evolution of number and mean volum of thrombocytes can be predictors of evolution of infection with Influenza A(H1N): from seven exitus three pacients had thrombopenia with low MPV.