Malarial thrombocytopenic bleeding among haemophiliacs in a tropical setting
Incidence, pattern and risk factors in Northern Nigeria
Malarial thrombocytopenia (MT) and its haemorrhagic effect on haemophiliacs have not been studied in Nigeria. We hypothesized that the risk of malarial thrombocytopenic bleeding (MTB) among haemophiliacs with MT in Nigeria would be affected by demographic and clinical factors that may affect platelet function, host susceptibility to malaria or its clinical severity. To determine incidence, pattern, demographic and clinical risk factors of MTB among haemophiliacs with MT, we retrospectively studied 95 haemophiliacs with MT with respect to MTB, age, sex, severity of haemophilia, thrombocytopenia, parasitemia, haemoglobin (Hb) phenotypes and ABO blood groups. Relative risk (RR) of MTB for each parameter was calculated. Out of 95 haemophiliacs with MT, 16(16.8%) had muco-cutaneous MTB. No significant difference in frequency of severe haemophilia between haemophiliacs with and without MTB (50% vs.48.1%, RR=1.1, p=0.89). But haemophiliacs with MTB had higher frequency of age < 5 years (81.3% vs. 38.0%: RR=5.2, p=0.006), higher frequency of platelet count <20 x 109/L (81.3% vs. 21.5%, RR=9.4, p=0.0002), higher frequency of malaria parasite density ≥3+ (68.7% vs. 11.4%, RR=8.3, p=0.0001), higher frequency of HbAA phenotype (75% vs. 44.3%, RR=3.1, p=0.04), and higher frequency of non-O blood groups (62.5% vs. 32.9%, RR=2.7, p=0.03). Incidence of MTB among haemophiliacs with MT was 16.8%. Risk of MTB was not affected by severity of haemophilia, but the risk was increased by young age, severity of parasitemia and thrombocytopenia, non-O blood group and HbAA phenotype. Therefore, haemophiliacs presenting with triad of fever, thrombocytopenia and muco-cutaneous bleeding in the tropics should be investigated for malaria.