When malaria imitates thrombotic thrombocytopenic purpura: importance of patient history and physician awareness of uncommon diseases

A 43-year-old man in a rapidly deteriorating state was transferred to the intensive care unit (ICU) from the gastroenterology unit, where he had been admitted due to an episode of syncope associated with abdominal pain, diarrhea, and jaundice. Diagnostic tests performed before the ICU admission showed normocytic anemia (hemoglobin, 9.3 g/dl; reference range [RR], 13–18 g/dl), severe thrombocytopenia (35 G/l; RR, 150–450 G/l), hyperbilirubinemia (176 µmol/l; RR, 5.1–20.5 µmol/l), elevated alanine and aspartate transaminase levels (79 IU/l and 99 IU/l, respectively; RR, 0–50 IU/l), undetectable haptoglobin, as well as elevated levels of inflammatory markers (C-reactive protein, 178 mg/l; RR, 0.08–3.1 mg/l). Abdominal ultrasonography showed hepatosplenomegaly. The medical history was impossible to obtain because of the patient’s altered mental status. Computed tomography (CT) scans of the head showed signs of brain hypoxia (Figure 1A and 1B). In the ICU, the patient was highly agitated with signs of delirium, and presented with hypotension and tachycardia. He was sedated and intubated. Mechanical ventilation was initiated. A diagnosis of thrombotic thrombocytopenic purpura (TTP) was suggested, and 4 units of fresh frozen plasma (FFP) were administered. A screening test revealed low activity of ADAMTS13 protease; therefore, 2 rounds of plasmapheresis were performed and steroids were administered while awaiting a confirmatory ADAMTS13 functional inhibitor assay result. The patient’s condition stabilized, and the platelet count increased. However, a recurrent high fever was observed, and blood tests revealed an increased level of creatinine (142 µmol/l; RR, 64–104 µmol/l) and further elevation of inflammatory marker concentrations, while features of hemolysis persisted. Chest CT was performed, which showed fluid in the pleural cavity and pericardium along with enlarged retroperitoneal lymph nodes (Figure 1C and 1D). The confirmatory test result for TTP was negative but the manual blood smear showed atypical erythrocytes with uncommon inclusions (Figure 1E and 1F). At the same time, physicians learned from the Consulate Office that the patient had stayed in Tanzania for a month before the current hospitalization. Consequently, a screening test for malaria was performed, and the result was positive for Plasmodium falciparum. Severe cerebral malaria was diagnosed and treatment with intravenous artesunate was started. One day after the administration of the drug, parasitemia reduced from 4.95% to 0.8%, and the patient’s general condition gradually improved. After 7 days in the ICU, the patient was extubated. He remained conscious and verbally responsive. He was transported to the infectious diseases department and discharged on his own request after 3 days.

TTP often affects abdominal vessels and the brain, most commonly through microangiopathy and consequential ischemia. Nonspecific abnormalities in blood test results are the most frequent manifestation in laboratory workup.¹ According to the American Society of Hematology, the ADAMTS13 activity assay is the first step in TTP diagnosis.² Treatment involves steroids, therapeutic plasma exchange, and FFP or blood transfusions. Malaria may imitate TTP with intravascular coagulation, severe anemia, and hyperlactatemia, so the TTP treatment may improve the patient’s condition despite misdiagnosis.³ P. falciparum infection often leads to cerebral malaria.⁴ Artesunate is considered the drug of choice in severe malaria.^3,5 In Poland, due to the rarity of malaria, physicians are far more likely to suspect and diagnose TTP. It is worth checking the possibility of a systemic, parasitic infection or other clinically similar diseases if there is even a single symptom atypical for TTP, for example, elevated liver enzyme levels. The additional investigation may protect patients from unnecessary medical procedures.