The triage nurse calls a physician to evaluate a newly arrived patient in the emergency department. The patient, a 34-year-old woman with no significant past medical history, describes a rapidly progressive, profound exhaustion over the last 72 hours, accompanied by intermittent episodes of confusion and 'purple spots' appearing on her legs.
Vital signs include a heart rate of 108/min, blood pressure of 142/88 mmHg, temperature of 37.8°C (100.0°F), and oxygen saturation of 98% on room air. Examination shows widespread lower extremity petechiae, mild scleral icterus, and temporal disorientation without focal neurological deficits.
| Test | Result | Reference Range |
|---|---|---|
| Hemoglobin | 7.6 g/dL | 12.0-15.5 g/dL |
| Platelet count | 18,000/mm³ | 150,000-400,000/mm³ |
| Leukocyte count | 8,400/mm³ | 4,500-11,000/mm³ |
| Creatinine | 1.3 mg/dL | 0.6-1.1 mg/dL |
| Total bilirubin | 3.2 mg/dL | 0.1-1.2 mg/dL |
| Indirect bilirubin | 2.8 mg/dL | 0.1-0.8 mg/dL |
| Lactate dehydrogenase (LDH) | 1,150 U/L | 140-280 U/L |
| Prothrombin time (PT) | 12 sec | 11-15 sec |
| Activated PTT (aPTT) | 30 sec | 25-40 sec |
Based on the clinical presentation and initial laboratory data, arrange the following diagnostic and therapeutic steps in the strictly required chronological sequence to properly manage this patient's suspected hematologic emergency.
- 1Evaluate a peripheral blood smear to confirm the presence of microangiopathic hemolytic anemia
- 2Draw blood samples for ADAMTS13 activity and inhibitor testing
- 3Initiate urgent therapeutic plasma exchange (TPE) without waiting for specific assay results
- 4Monitor daily platelet counts and lactate dehydrogenase (LDH) levels