Differential Diagnosis for Coagulopathy in a 76-year-old Patient
Single Most Likely Diagnosis
- Disseminated Intravascular Coagulation (DIC): The presence of urinary tract infection leading to sepsis, tachycardia, hypertension, thrombocytopenia (platelet count 77,000), elevated prothrombin time (PT) and partial thromboplastin time (PTT), and schistocytes on peripheral blood smear are highly suggestive of DIC. The condition is characterized by both widespread clotting and bleeding, which can be triggered by severe infections like sepsis.
Other Likely Diagnoses
- Heparin-Induced Thrombocytopenia (HIT): Although the patient is on unfractionated heparin, the presence of thrombocytopenia and elevated PT/PTT could also suggest HIT, especially if there's a recent drop in platelet count after heparin initiation. However, the clinical context of sepsis and the presence of schistocytes lean more towards DIC.
- Thrombotic Thrombocytopenic Purpura (TTP): This condition is characterized by thrombocytopenia, microangiopathic hemolytic anemia (schistocytes on smear), renal failure, and neurological symptoms. While some features are present, the absence of mentioned neurological symptoms or renal failure makes it less likely than DIC.
Do Not Miss Diagnoses
- Severe Vitamin K Deficiency: Although less likely given the acute presentation, severe vitamin K deficiency could lead to elevated PT/PTT. However, it would not typically cause thrombocytopenia or schistocytes.
- Antiphospholipid Syndrome: This condition can cause thrombocytopenia and prolongation of PT/PTT but is less likely given the acute onset in the context of sepsis.
Rare Diagnoses
- Atypical Hemolytic Uremic Syndrome (aHUS): Characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure, aHUS is a rare condition that could present similarly to TTP or DIC but is less likely given the context of sepsis.
- Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare, acquired, life-threatening disease of the blood characterized by the destruction of red blood cells, bone marrow failure, and the potential for thrombotic events. The presence of schistocytes could suggest PNH, but the clinical context provided does not strongly support this diagnosis.