Acute haemorrhagic encephalomyelitis (AHEM), also known as acute haemorrhagic 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 characterised by an acute rapidly progressive fulminant inflammation of the white matter. The cause is unclear but may be post-infectious (either viral or bacterial).
AHEM may more commonly occur in young adults, contrary to ADEM, which is more commonly diagnosed in children 5. It has been reported in older adults 6. There is no gender predilection.
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 4.
AHEM is related to autoimmune cross reaction to the myelin antigens, and is defined by the presence of necrotising venulitis with perivascular haemorrhages, diffuse CNS ischemic lesions and myelin destruction 4. Many authors consider it a fulminant variant of ADEM, forming a spectrum of disease 4,5.
- marked cerebral oedema and congestion, often with herniation
- punctate haemorrhages within the cerebral white matter, not infrequently necrotic
- not uncommonly presence of necrosis in basal ganglia
- typically no involvement of the spinal cord
Imaging appearances are dominated by fibrinoid venous necrosis, leading to acute haemorrhage with fibrin exudates and neutrophilic debris:
- classically haemorrhages around the necrotic venules resembling “ring and ball”
- white matter ischemic changes adjacent to necrotic postcapillary venules
- haemorrhage more prominent than demyelination
- no specific immunohistochemical pattern 4
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 haemorrhages and extensive mass effect and surrounding edema.
- possible involvement of ganglia and thalami
Treatment and prognosis
Acute haemorrhagic 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 2.
General imaging differential considerations include:
- 1. Geerts Y, Dehaene I, Lammens M. Acute hemorrhagic leukoencephalitis. Acta Neurol Belg. 1992;91 (4): 201-11. Pubmed citation
- 2. Hurst EW. Acute hemorrhagic leukoencephalitis: a previously undefined entity. (1941) Med J Aust. 1:1–6
- 3. Lee HY, Chang KH, Kim JH et-al. Serial MR imaging findings of acute hemorrhagic leukoencephalitis: a case report. AJNR Am J Neuroradiol. 2005;26 (8): 1996-9. Pubmed citation
- 4. Yachnis AT, Rivera-Zengotita ML. Neuropathology,A Volume in the High Yield Pathology Series (Expert Consult - Online and Print),1. Saunders. (2013) ISBN:1416062203. Read it at Google Books - Find it at Amazon, pp. 287-8
- 5. Borlot F, da Paz JA, Casella EB et-al. Acute hemorrhagic encephalomyelitis in childhood: Case report and literature review. J Pediatr Neurosci. 2011;6 (1): 48-51. Free text at pubmed - Pubmed citation
- 6. Pinto PS, Taipa R, Moreira B et-al. Acute hemorrhagic leukoencephalitis with severe brainstem and spinal cord involvement: MRI features with neuropathological confirmation. J Magn Reson Imaging. 2011;33 (4): 957-61. doi:10.1002/jmri.22505 - Pubmed citation
- primary demyelinating disorders
- clinically isolated syndrome (CIS)
- radiologically isolated syndrome (RIS)
multiple sclerosis (MS)
- McDonald diagnostic criteria for MS (current 2017 revision)
- neuromyelitis optica (NMO) (Devic disease)
- acute disseminated encephalomyelitis (ADEM) and acute haemorrhagic encephalomyelitis (AHEM)
- tumefactive demyelinating lesions
- transverse myelitis
- chronic inflammatory demyelinating polyneuropathy (CIDP)
- Guillain-Barre Syndrome (GBS)
- anti-MOG associated encephalomyelitis
- primary demyelinating disorders