Absence of Proof Is Not Proof of Absence

Meeting: Hospital Medicine 2012, April 1-4, San Diego, Calif.

Abstract number: 97764

Case Presentation:

A 59–year–old man presented with sudden onset left–sided facial droop, aphasia, and left upper and lower extremity weakness. His medical history included hepatitis C, cirrhosis, and hepatocellular carcinoma. CT of the brain showed no acute process, and his deficits resolved within an hour. His vital signs were within normal limits and his exam was otherwise unremarkable. Brain MRI revealed acute infarctions in the right basal ganglia and the left periventricular white matter. Transthoracic echocardiogram and CT angiogram of the neck and brain were normal. Laboratory evaluation revealed hemoglobin 8.3 g/dL and platelet count 20,000/mL. His electronic record revealed progressive thrombocytopenia and anemia over the past month. His stool was heme–negative. Additional labs revealed total bilirubin 2.1 mg/dL, LDH 522 U/L, reticulocytes 6.55%, haptoglobin 1 mg/dL. INR, PTT, and fibrinogen were normal. Coombs test was negative. Blood smear showed no schistocytes. Creatinine was 0.9 mg/dL. At this time the diagnosis of thrombotic thrombocytopenia purpura (TTP) was considered but was ultimately rejected given the patient’s normal renal function, lack of fever, and absence of schistocytes on the blood smear. Over the next 36 hours, the patient had two episodes of transient facial droop, aphasia, and upper extremity weakness. His mental status remained intact during these episodes. Repeat CT of the brain showed evidence of new left frontal lobe infarction. His platelets dropped below 10,000/mL. Given his fluctuating neurologic status, severe thrombocytopenia, and hemolytic anemia he was transferred to an academic medical center for further evaluation. A repeat blood smear revealed schistocytes and the diagnosis of TTP was confirmed. Plasmapheresis was initiated; his platelet count recovered and his LDH normalized. ADAMTS13 activity was measured at <5%. He had no further episodes of neurologic deficits and he was discharged home to continue outpatient plasmapheresis.


Hospitalists commonly associate TTP with the classic pentad of fever, neurologic abnormalities, renal failure, thrombocytopenia, and microangiopathic hemolytic anemia. However, there is wide variability in the clinical presentation of TTP and patients may not present with all elements of the classic pentad. Our patient never developed fever or renal failure, and his initial blood smear showed no schistocytes despite clear laboratory evidence of hemolysis. His neurologic abnormalities were focal deficits rather than confusion or altered mental status. These factors combined to cloud his clinical picture and delayed the diagnosis.


TTP should be suspected in patients with thrombocytopenia and hemolytic anemia, even in the absence of the classic pentad of symptoms.

Figure 1Peripheral blood smear done at the time of admission.

To cite this abstract:

Wachter A, Stephany A. Absence of Proof Is Not Proof of Absence. Abstract published at Hospital Medicine 2012, April 1-4, San Diego, Calif. Abstract 97764. Journal of Hospital Medicine. 2012; 7 (suppl 2). https://www.shmabstracts.com/abstract/absence-of-proof-is-not-proof-of-absence/. Accessed March 28, 2020.

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