RESUMO
A bleeding syndrome due to severe prothrombin complex deficiency is reported in 93 infants. Most were breast fed (98 per cent), aged 2 weeks to 1 year and there were no serious preceding or associated diseases. Hemorrhagic diathesis, pallor and mild hepatomegaly were the major manifestations. The incidence of intracr anial bleeding was strikingly high (63 per cent) particularly with subdural and subarachnoid hemorrhage. Acute onset, short course and rapid clinical and laboratory improvement after vitamin K therapy were observed. Mortality rate was 35 per cent but has been reduced to 17 per cent since 1969. The location of bleeding, prompt diagnosis and early treatment are the major factors affecting prognosis. Severe prothrombin complex deficiency due to vitamin K deficiency accounted for the pathogenesis of bleeding. Possible causes of vitamin K deficiency were discussed but definite conclusions could not be drawn.