Hemorrhagic shock and encephalopathy syndrome

Hemorrhagic shock and encephalopathy syndrome (HSES) is a rare pediatric encephalopathy syndrome with a high mortality rate.

Epidemiology

Hemorrhagic shock and encephalopathy syndrome is considered rare, although the exact global incidence and prevalence is not known. The condition occurs in infants and is more common in winter months ^1,2.

Clinical presentation

Hemorrhagic shock and encephalopathy syndrome is an acute-onset illness ^1,2. Clinical manifestations may be diverse, including ^1,2:

• fever

• shock

• encephalopathy, with seizures (including status epilepticus) and decreased conscious state

• hemorrhagic tendency due to disseminated intravascular coagulation

• diarrhea and/or vomiting

• multiorgan dysfunction with prominent hepatic and renal failure

  • respiratory failure is notably not a common clinical feature

Pathology

The pathogenesis of hemorrhagic shock and encephalopathy syndrome is unknown ^1,2. It is thought that there may be a cytokine storm present, possibly triggered by a preceding viral infection ^1,2. However, in many cases no infective trigger is ever identified ^1,2.

Radiographic features

CT

CT brain can initially be normal, even as patients are critically unwell ^1,2. As the condition progresses, there is loss of grey-white matter interfaces indicative of cerebral edema, and development of watershed infarctions ^1,2. If patients survive the acute illness, there may be evidence of cortical laminar necrosis and eventual cerebral atrophy ².

MRI

MRI brain is usually abnormal even in the early stages of the illness ^2-4. The most prominent features, as seen on CT, are those of cerebral edema and watershed infarctions ².

• T1: often normal during acute illness, with increased cortical signal intensity indicative of cortical laminar necrosis appreciated later ²

• T2/FLAIR: hyperintensity and swelling of the cortex ^2-4

• DWI: high signal regions in subcortical white matter, particularly in watershed zones indicative of acute infarction, but also in other patterns (e.g. bright tree appearance) ^2-4

Treatment and prognosis

No effective treatment options exist ^1,2. Management is supportive in an intensive care unit setting, including management of raised intracranial pressure and multi-organ dysfunction ^1,2. Immunomodulatory therapies have been utilized but without certain benefit ².

Prognosis of hemorrhagic shock and encephalopathy syndrome is very poor, with at least one-third of patients across case series dying due to the illness ^1,2. There is a high neurological morbidity in survivors of the condition ^1,2.

History and etymology

Hemorrhagic shock and encephalopathy syndrome was first described in a 1983 seminal case series ⁵.

Differential diagnosis

• acute necrotizing encephalopathy

• acute encephalopathy with biphasic seizures and late reduced diffusion (AESD)

• acute leukoencephalopathy with restricted diffusion (ALERD)