RESUMO
High altitude polycythemia is one of the altitude illnesses. Sana'a region is located at high altitude which reaches 3600 meters above the sea level. To determine the hematological and clinical features of polycythemic patients residing in Sana'a region and to clarify the effect of high altitude in causing polycythemia. Hematological, clinical and demographic data were obtained from 30 polycythemic patients [26 males, 4 females, aged 26 to 85 years residing Sana'a region and referred to the National Centre of Public Health Laboratories in Sana'a city for the first time venesection. All studied samples showed high hemoglobin levels [mean 18.85 g/dl for both sexes], normal platelet counts [228 and 267 x10[9]/L for males and females, respectively], normal white cell counts in 96.7% of the cases [means 6.01 to 5.98 x10[9]/L. Their clinical features showed predominance of headache, ruddy cyanosis, dyspnea and night sweating by 86.7%, 76.7%, 70% and 60%, respectively, Hypertension, joint pain, renal disease, peptic ulcer were less commonly mentioned by 36.7%, 20%, 13.3%, and 10%, respectively. Hemorrhage, pruritus, splenomegaly, heart disease and liver disease were observed by only 6.67% each. Findings suggest that secondary polycythemia is predominant among polycythemic patients due to the high altitude of Sana'a region. Findings needs to be confirmed by studying a larger sample and extended to investigate the erythropoietin level and JAK2V617F mutation for accurate diagnosis