HUS-induced cardiac and circulatory failure is reversible using cardiopulmonary bypass as rescue

Extra-renal involvement in hemolytic uremic syndrome (HUS) includes gastrointestinal, pancreatic, hepatic, neurological and cardiac manifestations. The current 3–5% mortality rate in HUS patients is primarily attributed to complications related to the central nervous system and the heart. In this brief report, we illustrate that severe cardiac involvement in a patient with HUS is potentially reversible using cardiopulmonary bypass as rescue.

A 12-year-old boy was diagnosed with enterohemorrhagic Escherichia coli-induced HUS related to E. coli serotypes O55:H7 and O121:H19. The patient developed anuria and hypertension of 150/105 mmHg and had neurological symptoms, with lethargy, confusion and later a tonic-clonic seizure successfully treated with midazolam. Laboratory tests on blood samples revealed acute renal failure, with a creatinine level of 3.98 mg/dL, thrombocytopenia of 47 × 10⁹/L, lactate dehydrogenase level of 3620 IU/L, low haptoglobin (<20 mg/dL), anemia (10.0 g/dL) and schistocytes on blood smears. Peritoneal dialysis was initiated without complications. Serum potassium level was normal. At day 3, the patient suffered cardiac arrest on two separate occasions. Troponin-T, creatine kinase and creatine kinase-MB levels were significantly increased. The second episode of cardiac arrest could not be reversed with advanced cardiopulmonary resuscitation, and a cardiopulmonary bypass circuit was established. Declining cardiac pump function to a near non-contractile state with an ejection fraction of <10% was observed on echocardiography. This persisted during the following days. After the patient had been on the cardiopulmonary bypass (CPB) circuit for 7 days, the myocardium slowly recovered function. Three days later, the CPB was successfully discontinued; the echocardiography showed near-normal ejection fraction, and electrocardiography (ECG) showed sinus rhythm.

Fatal outcome in patients with HUS may be the result of severe cardiac involvement. The present case illustrates the need for intensive supportive care, including the use of CPB, as the cardiac symptoms in HUS patients may be reversible. We suggest the monitoring of cardiac-specific enzymes, ECG and echocardiography in high-risk patients.