A 34-year-old woman presents to the emergency department with a 3-day history of profound fatigue, intermittent confusion, and easy bruising. Her temperature is 38.2°C (100.8°F), pulse is 105/min, and blood pressure is 110/70 mm Hg. Physical examination reveals scleral icterus and scattered petechiae on the lower extremities. Neurological examination reveals mild disorientation to time and place, but no focal motor or sensory deficits. Laboratory testing reveals the following:
| Laboratory Test | Result | Reference Range |
|---|---|---|
| Hemoglobin | 8.2 g/dL | 12.0 - 16.0 g/dL |
| Platelets | 18,000/mm³ | 150,000 - 400,000/mm³ |
| Leukocytes | 8,500/mm³ | 4,500 - 11,000/mm³ |
| Blood urea nitrogen | 42 mg/dL | 7 - 18 mg/dL |
| Creatinine | 2.1 mg/dL | 0.6 - 1.2 mg/dL |
| Total bilirubin | 3.5 mg/dL | 0.1 - 1.2 mg/dL |
| Indirect bilirubin | 2.8 mg/dL | 0.1 - 0.8 mg/dL |
| Lactate dehydrogenase | 850 U/L | 100 - 250 U/L |
| Prothrombin time | 12 sec | 11 - 15 sec |
| Partial thromboplastin time | 30 sec | 25 - 40 sec |
A peripheral blood smear demonstrates numerous fragmented red blood cells and a paucity of platelets. Which of the following is the most appropriate next step in management for this patient?
- AAdministration of platelet transfusion
- BIntravenous immunoglobulin and corticosteroids
- CInfusion of cryoprecipitate and fresh frozen plasma
- DObservation and serial laboratory monitoring
- Initiation of plasma exchangeCevap
Cevap
The correct answer is the initiation of plasma exchange.
The patient's presentation of fever, confusion, renal dysfunction, severe thrombocytopenia, and microangiopathic hemolytic anemia (MAHA) is characteristic of Thrombotic Thrombocytopenic Purpura (TTP). The presence of schistocytes on the peripheral blood smear confirms the mechanical destruction of red blood cells as they traverse microthrombi in small vessels. The normal prothrombin time (PT) and partial thromboplastin time (PTT) are crucial findings that differentiate TTP from Disseminated Intravascular Coagulation (DIC). TTP is driven by a deficiency of the metalloproteinase ADAMTS13 (usually due to an acquired autoantibody), leading to uncleaved, ultra-large von Willebrand factor multimers that trap platelets. Because this is a life-threatening emergency with a mortality rate exceeding 90% without treatment, the immediate and definitive intervention is plasma exchange (plasmapheresis). This procedure removes the autoantibodies and replenishes the deficient ADAMTS13 enzyme.
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Anahtar Kavram
The diagnosis and emergent management of Thrombotic Thrombocytopenic Purpura (TTP), characterized by microangiopathic hemolytic anemia, thrombocytopenia, and normal coagulation studies, requiring immediate plasma exchange.