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Hemorrhagic Shock and Encephalopathy Syndrome (HSES)

By Elizabeth J. Palumbo, MD, The Pediatric Group, Fairfax, VA

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Hemorrhagic shock and encephalopathy syndrome is an extremely rare disease characterized by acute onset of severe shock, coagulopathy, encephalopathy, and hepatic and renal dysfunction in previously healthy children, resulting in death or catastrophic neurologic outcome. Diagnosis is by exclusion (particularly of sepsis, Reye syndrome, hemolytic-uremic syndrome, and thrombotic thrombocytopenic purpura). Treatment is supportive.

Hemorrhagic shock and encephalopathy syndrome (HSES) occurs predominantly in infants aged 3 to 8 mo (median age, 5 mo) but has been reported in a 15 yr old. HSES resembles heatstroke, with extremely high temperature and multiple organ dysfunction, but the cause is unknown. Overwrapping of infants who have febrile illness has been suggested, but evidence is slim. Other theories include a reaction to intestinal or environmental toxins, pancreatic release of trypsin, or an unidentified virus or bacterium. Many investigators suspect an underlying gene defect. Diffuse cerebral edema with herniation and focal hemorrhages and infarcts in the cerebral cortex and other organs are common. The lungs and myocardium are not primarily involved.

Symptoms and Signs

A prodrome of fever, upper respiratory tract symptoms, or vomiting and diarrhea occurs in most patients. The major features are an acute onset of encephalopathy, cerebral edema (manifested as seizures, coma, and hypotonia), and severe shock (ie, hypotension and poor perfusion). Other common features include hyperpyrexia (up to 43.9° C rectally), bloody or watery diarrhea, disseminated intravascular coagulation (DIC), myoglobinuria, and rhabdomyolysis.


  • Laboratory testing

Similar symptoms can result from sepsis, Reye syndrome, hemolytic-uremic syndrome, thrombotic thrombocytopenic purpura, and familial or acquired erythrophagocytic lymphohistiocytosis. Patients require laboratory evaluation, including blood, urine, stool, sputum, and CSF cultures, ABG, CBC differential/platelets, electrolytes, BUN, creatinine, PT/PTT, liver function tests, C-reactive protein, CK, lactate, fibrin, fibrin split products, ferritin, and lipids, and head CT and EEG. Multiple abnormalities include metabolic acidosis, elevated liver transaminases, DIC, elevated CK, acute renal failure, thrombocytopenia, falling Hct, leukocytosis, hypoglycemia, and hyperkalemia. Bacteriologic and viral cultures are negative. Diagnosis is by exclusion.


In all cases, > 60% of patients die, and 70% of survivors have severe neurologic sequelae. Early detection and treatment are important to minimize morbidity and mortality.


  • Supportive measures

Treatment is entirely supportive. Infusions of large volumes of isotonic solutions and blood products (fresh frozen plasma, albumin, whole blood, packed RBCs) along with inotropic support (eg, dopamine, epinephrine) and correction of acid-base abnormalities are necessary to maintain circulation. Marked temperature elevation (eg, > 39° C) requires external cooling (see Treatment). Increased intracranial pressure caused by cerebral edema requires intubation and hyperventilation. DIC often progresses despite use of fresh frozen plasma.

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* This is the Professional Version. *