Which condition is most likely indicated by an 8-month-old male presenting with hemarthrosis and hematuria with no history of trauma?

The presence of hemarthrosis (bleeding into the joints) and hematuria (blood in the urine) in an 8-month-old male without any history of trauma strongly suggests a bleeding disorder. In this context, the symptoms are characteristic of hemophilia, particularly given that it is a hereditary condition often found in males due to its X-linked recessive inheritance pattern.

Hemophilia is caused by a deficiency in specific clotting factors, usually factor VIII (hemophilia A) or factor IX (hemophilia B), leading to an inability to form stable blood clots. This results in spontaneous bleeding episodes, such as those observed in hemarthrosis, where blood leaks into the joints, causing swelling and pain. Hematuria can occur due to bleeding in the urinary tract.

Other conditions such as thrombocytopenia could cause bleeding but are less specific for joint bleeding and require further exploration of platelet counts and function. Vitamin K deficiency would typically present with additional clinical findings, such as a broader range of bleeding issues, and is less common in infants who are otherwise healthy, particularly if they are breastfed. Blood vessel malformations, while possible, are less likely to cause spontaneous hemarthrosis in such a young child.

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