Indian Journal of Medical Sciences Medknow Publications on behalf of Indian Journal of Medical Sciences Trust ISSN: 0019-5359 EISSN: 1998-3654 Vol. 64, Num. 12, 2010, pp. 560-563

Indian Journal of Medical Sciences, Vol. 64, No. 12, December, 2010, pp. 560-563

Letter to Editor

Hemi brain demyelination - A variant of acute disseminated encephalomyelitis

CJ Suresh Chandran¹, MH Saddiq², Prameela Joji², Madhavan Unni³

¹ Department of Neurology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
² Department of Pediatrics, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
³ Department of Radiology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India

Correspondence Address:
C J Suresh Chandran
Kerala Institute of Medical Sciences, Trivandrum, Kerala
India
drceejay@rediffmail.com

Code Number: ms10006

PMID: 21258155

DOI: 10.4103/0019-5359.75933

Sir,

Acute disseminated encephalomyelitis (ADEM) is an acquired inflammatory demyelinating disorder characterized by disseminated and multifocal involvement of the brain and spinal cord. ^[1] Unilateral brain involvement has been reported infrequently in ADEM. ^[2],[3] We report a rare case of hemi brain demyelination.

An 8-year-old boy was referred to our hospital. He had been admitted to another hospital on the previous day, with left focal to secondary generalized seizures and left hemiplegia. He had a preceding upper respiratory tract infection, which had resolved in 3 days. There was no recent vaccination. Since his level of consciousness deteriorated, he was transferred to our center. The boy was in a coma (GCS E1M3V1). There was no fever. The pupils were mid-dilated and reacted sluggishly and the oculocephalic reflex was absent. Fundoscopy was normal and no other signs of raised intracranial pressure were noted. There were no signs of meningeal irritation. He had dense left hemiplegia (0/5 in upper and lower limbs). No involuntary movements were noted. He had poor respiratory effort and thus required respiratory support by assisted ventilation.

Magnetic Resonance Imaging (MRI) of the brain showed hyperintense lesions on the T2 and FLAIR sequences involving the right half of the brainstem, right cerebellum, right thalamus, right basal ganglia, right cortical gray matter and subcortical white matter. These lesions were isointense on T1 and did not show any diffusion restriction. Although there was predominant involvement of the right side of the brain, there were isolated lesions in the left hemisphere (T2 and FLAIR hyperintensities involving the left thalamus, left anterior and medial temporal lobes). The right half of brainstem and right cerebral hemisphere were swollen. There was mass effect on the right lateral ventricle [Figure - 1],[Figure - 2],[Figure - 3],[Figure - 4]. There was partial enhancement of some lesions on contrast administration. MR angiography and MRI spine were normal. Cerebrospinal fluid (CSF) study showed elevated protein (150 mg/dl, normal range 20-40 mg/dl), normal sugar (68 mg/dl, corresponding blood sugar was 118 mg/dl) and 5 lymphocytes/mm ³ . CSF oligoclonal band, Indian ink stain for Cryptococcus and Herpes simplex virus (type 1) PCR were negative. CSF gram stain did not yield any organisms. Other viral screening tests could not be done. Vasculitic workup, ELISA for HIV, and serum and CSF VDRL test were negative. EEG showed diffuse attenuation of rhythm and ruled out non-convulsive status epilepticus. A diagnosis of ADEM with predominantly right-sided demyelination was made.

His management comprised intravenous methyl prednisolone (30 mg/kg) once daily, intravenous aciclovir (10 mg/kg intravenous 8 hourly), phenytoin and measures to reduce intracranial pressure (mannitol and hyperventilation). His brain stem function deteriorated and he developed hypotension. He demised 18 hours after admission. Unfortunately, a post-mortem brain biopsy could not be obtained.

ADEM is an acquired monophasic inflammatory demyelinating disease of the central nervous system, characterized by scattered focal or multifocal inflammation of the brain and/or spinal cord. ^[1] A number of variants of ADEM have been described, namely, tumefactive demyelination (Marburg′s disease), acute hemorrhagic leukoencephalitis (AHLE), Balo′s concentric sclerosis and focal or site restricted forms (optic neuritis, myelitis, cerebellitis). ^[1] Our case was peculiar due to the fact that demyelination affected predominantly the right half of brain with contiguous involvement of the right cortex, subcortical white matter, basal ganglia, brainstem and cerebellum. This is atypical compared to the usual bilateral and multifocal lesions. There was also extensive cortical gray matter involvement in addition to the deep gray matter involvement in the basal ganglia and thalamus. There have been isolated case reports of hemi cerebellitis in children and solitary hemispheric tumefactive demyelinating lesions. ^[2],[3] Herpes simplex encephalitis is a differential diagnosis worth considering. However, the extensive involvement of white matter, deep gray matter, brain stem and cerebellum as well as a normal EEG and negative PCR are the points against it. Inflammatory disorders with unilateral brain involvement include Rasmussen′s encephalitis, primary angitis of central nervous system and herpes zoster related vasculopathy. Rasmussen′s encephalitis is an inflammatory immune mediated disorder characterized by unilateral hemispheric atrophy, intractable seizures and progressive neurological dysfunction. MRI features include unilateral enlargement of CSF compartments with increased cortical and/or subcortical T2 and FLAIR signals and caudate head atrophy. ^[4] In primary angitis of central nervous system, the common pattern is multifocal, unilateral, proximal lesions in the anterior circulation. ^[5] Herpes zoster related vasculopathy also shows unilateral lesions in anterior circulation. ^[6]

To the best of our knowledge, no previous cases of unilateral demyelination involving predominantly one half of cerebral hemisphere, brainstem and cerebellum have been reported. Our case is a unique variant of ADEM, namely hemi brain demyelination or predominantly unilateral demyelination. However, in the absence of a histological diagnosis, an infective hemi encephalitis or predominantly unilateral encephalitis is also a possibility.

References

1.	Murthy JM. Acute disseminated encephalomyelitis. Neurol India 2002;50:238-43.  Back to cited text no. 1  [PUBMED]
2.	Garcia-Cazorla A, Olivan JA, Pancho C, Sans A, Boix C, Campistol J. Infectious acute hemicerebellitis. J Child Neurol 2004;19:390-2.  Back to cited text no. 2
3.	Singh S, Alexander M, Sase N, Korah IP. Solitary hemispheric demyelination in acute disseminated encephalomyelitis: Clinicoradiological correlation. Australas Radiol 2003;47:29-36.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]
4.	Bien CG, Granata T, Antozzi C, Cross JH, Dulac O, Kurthen M, et al. Pathogenesis, diagnosis and treatment of Rasmussen encephalitis: A European consensus statement. Brain 2005;128:454-71.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.	Aviv RI, Benseler SM, Silverman ED, Tyrrel PN, Deveber G, Tsang LM, et al. MR imaging and angiography of primary CNS vasculitis of childhood. Am J Neuroradiol 2006;27:192-9.  Back to cited text no. 5
6.	Eidelberg D, Sotrel A, Horoupian DS, Neumann E, Pumarola-Sune T, Price RW. Thrombotic cerebral vasculopathy associated with herpes zoster. Ann Neurol 1986;19:7-14.  Back to cited text no. 6

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