A 34-year-old woman is admitted to the intensive care unit with severe sepsis secondary to acute pyelonephritis. On her second day of admission, the nursing staff notes persistent bleeding from her intravenous catheter sites and new-onset ecchymoses over her extremities. Her temperature is 38.8°C (101.8°F), blood pressure is 90/60 mmHg, and pulse is 115/min. Laboratory studies are obtained and show the following:
| Laboratory Test | Result | Reference Range |
|---|---|---|
| Platelet count | 42,000/mm³ | 150,000 - 400,000/mm³ |
| Prothrombin time (PT) | 22 seconds | 11 - 15 seconds |
| Partial thromboplastin time (PTT) | 65 seconds | 25 - 40 seconds |
| Fibrinogen | 85 mg/dL | 150 - 400 mg/dL |
| D-dimer | 4,500 ng/mL FEU | < 500 ng/mL FEU |
Which of the following is the most likely diagnosis based on these laboratory findings?
- Disseminated intravascular coagulationAnswer
- BImmune thrombocytopenia
- CThrombotic thrombocytopenic purpura
- DVitamin K deficiency
- EHemophilia A
Answer
Disseminated intravascular coagulation
The correct answer is Disseminated intravascular coagulation (DIC). This patient's clinical presentation of sepsis with bleeding from intravenous sites, combined with a laboratory profile showing thrombocytopenia, prolonged PT, prolonged PTT, hypofibrinogenemia, and elevated D-dimer, is classic for DIC. In DIC, widespread systemic activation of the coagulation cascade leads to the rapid consumption of platelets and coagulation factors (which prolongs the PT and PTT and lowers fibrinogen). Concurrently, the fibrinolytic system is activated to break down the clots, resulting in significantly elevated fibrin degradation products, such as D-dimer.
Step-by-Step Solution
Key Concept
Disseminated intravascular coagulation manifests with widespread consumption of platelets and coagulation factors, leading to prolonged PT/PTT, thrombocytopenia, decreased fibrinogen, and elevated D-dimer.