Acute hemorrhagic leukoencephalitis

Central
nervous system complications associated with SARS-CoV-2 infection: integrative concepts of pathophysiology and case reports. Para-infectious autoimmunity. a Acute necrotizing encephalopathy (ANE). A 23-year-old SARS-CoV-2-positive female presented mainly with encephalopathy progressed to catatonia. C-reactive protein (CRP) was 72.3 mg/dl. CSF analysis was completely normal. Coronal (1) and axial (2) fluid-attenuated inversion recovery (FLAIR)/T2-weighted (T2W) MR images reveal signal hyperintensities of the ventromedial thalami and hippocampi. DWI (3) and ADC (4) images show slightly increased signal intensity on DWI but without low signal intensity on ADC to suggest diffusion restriction. Bilateral thalamic involvement is highly characteristic for ANE. Her neurological condition improved substantially following immune therapies that included intravenous immunoglobulin, intravenous pulse methylprednisolone, and rituximab. b Acute disseminated encephalomyelitis (ADEM). A 56-year-old SARS-COV-2 positive female admitted for diarrhea and hypoxemic respiratory symptoms that progressed to ARDS necessitating intubation. Notable laboratory findings were CRP of 31 mg/dl (reference range 0.00–0.40), ferritin of 799 ng/ml (reference range 15–150 ng/ml), D-Dimer of 362 ng/ml (reference range < 230 ng/ml), and IL-6 of 42 (reference range less < 5 pg/ml). Neurological examination was notable for severe encephalopathy and severe quadriplegia. Axial FlAIR MR images (1, 2, 3) demonstrate multiple periventricular white matter hyperintensity lesions, without corpus callosal involvement. There is no enhancement or restricted diffusion on DWI (4, 5, 6). These findings are consistent with acute disseminated encephalomyelitis. Patient received a 5-day course of intravenous pulse methylprednisolone (1000 mg/day) and tocilizumab 750 mg (8 mg/kg) intravenously. She improved substantially to the point of becoming fully awake and alert with 4/5 power of upper extremities and 3–4/5 power of lower extremities. Patient was discharged to an acute rehabilitation facility and then went home showing a steady neurological improvement
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Acute hemorrhagic encephalomyelitis (AHEM), also known as acute hemorrhagic leukoencephalitis (AHLE), Hurst disease or Weston Hurst syndrome, is a very rare form of demyelinating disease. It occurs sporadically and may be considered as the most severe form of acute disseminated encephalomyelitis (ADEM) and is characterized by an acute rapidly progressive fulminant inflammation of the white matter. The cause is unclear but may be post-infectious (either viral or bacterial).

Epidemiology

AHEM may more commonly occur in young adults, contrary to ADEM, which is more commonly diagnosed in children . It has been reported in older adults . There is no gender predilection.

Clinical presentation

Patients present with fever, neck stiffness, fatigue, headache, nausea and vomiting, seizures and coma.

A history of upper respiratory infection prior to presenting neurologic symptoms (interval 2 to 12 days) may be present in ~50% of cases .

Pathology

AHEM is related to autoimmune cross reaction to the myelin antigens, and is defined by the presence of necrotizing venulitis with perivascular hemorrhages, diffuse CNS ischemic lesions and myelin destruction . Many authors consider it a fulminant variant of ADEM, forming a spectrum of disease .

Macroscopic appearance
  • marked cerebral edema and congestion, often with herniation
  • punctate hemorrhages within the cerebral white matter, not infrequently necrotic
  • not uncommonly presence of necrosis in basal ganglia
  • typically no involvement of the spinal cord
Microscopic appearance

Imaging appearances are dominated by fibrinoid venous necrosis, leading to acute hemorrhage with fibrin exudates and neutrophilic debris:

  • classically hemorrhages around the necrotic venules resembling “ring and ball”
  • white matter ischemic changes adjacent to necrotic postcapillary venules
  • hemorrhage more prominent than demyelination
  • no specific immunohistochemical pattern

Radiographic features

MRI

This is the gold-standard and may depict aforementioned morphologic changes such as:

  • large tumefactive lesions involving the white matter and sparing the cortex
  • associated punctate hemorrhages and extensive mass effect and surrounding edema.
  • possible involvement of ganglia and thalami

Detection of cerebral microhemorrhages by GRE or the more sensitive susceptibility weighted images (SWI) is an important finding and may allow for differentiation from ADEM.

Treatment and prognosis

Acute hemorrhagic leukoencephalitis is associated with a very poor prognosis with the majority of affected individuals succumbing to the disease.

History and etymology

It was first described by Edward Weston Hurst (1900-1980), a British neurologist, in 1941 .

Differential diagnosis

General imaging differential considerations include:

Siehe auch:
Assoziationen und Differentialdiagnosen zu Acute haemorrhagic encephalomyelitis (AHEM):
Leigh-Syndrom
 
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