Jenai was bitten by a tick and now has petechiae, blood in the stool, and spontaneous nosebleeds; labs show a decreased platelet count. Which disorder is most likely?

• A. Hemophilia
• B. Leukemia
• C. Acquired thrombocytopenia
• D. Lymphoma

Answer: (C)

When platelets are low, primary hemostasis is impaired, so small vessels bleed easily. This produces petechiae and mucosal bleeding, such as nosebleeds and blood in the stool. The combination of petechiae, mucosal bleeding, and a decreased platelet count points to a thrombocytopenic state.

Acquired thrombocytopenia fits best because it is an acquired, often immune-mediated, destruction or suppression of platelets leading to low counts and mucocutaneous bleeding. It contrasts with a clotting factor problem (hemophilia), where bleeding is typically into joints and muscles and the platelet count is normal with abnormal coagulation tests. Leukemia or lymphoma can cause low platelets, but they usually present with additional signs such as fatigue, infections, weight loss, or lymphadenopathy and abnormal blood smear findings indicating marrow infiltration, not just isolated mucosal bleeding after a tick bite.