|Year : 2016 | Volume
| Issue : 3 | Page : 179-181
Isolated extrapontine myelinolysis due to hemodialysis in a normonatremic individual
V Umamaheswara Reddy1, P Suneetha1, Amit Agrawal2
1 Department of Radiology, Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India
2 Department of Neurosurgery, Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India
|Date of Web Publication||28-Sep-2016|
Department of Neurosurgery, Narayana Medical College and Hospital, Chinthareddypalem, Nellore - 524 003, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Osmotic demyelination syndrome primarily occurs due to an imbalance of serum electrolytes and caused by rapid correction of hyponatremia. Isolated extrapontine myelinolysis is extremely rare, etiopathogenesis of which may be related to osmotic stress resulting from electrolyte disequilibrium. Extrapontine sites involved in osmotic demyelination syndrome show abundant oligodendrocytes, which are highly susceptible to osmotic stresses. Myelin vacuolization followed by intramyelinic splitting and disruption of myelin sheaths occur due to rapid osmolar fluctuations. Symmetrical hyperintensities showing restriction, which resolve in subsequent magnetic resonance scans can help in clinching the diagnosis of this condition in a given clinical setting.
Keywords: Extrapontine myelinolysis, hemodialysis, hyponatremia, pontine myelinolysis
|How to cite this article:|
Reddy V U, Suneetha P, Agrawal A. Isolated extrapontine myelinolysis due to hemodialysis in a normonatremic individual. J Med Soc 2016;30:179-81
|How to cite this URL:|
Reddy V U, Suneetha P, Agrawal A. Isolated extrapontine myelinolysis due to hemodialysis in a normonatremic individual. J Med Soc [serial online] 2016 [cited 2020 Oct 31];30:179-81. Available from: https://www.jmedsoc.org/text.asp?2016/30/3/179/191186
| Introduction|| |
Pontine and extrapontine myelinolysis due to rapid correction of hyponatremia is well documented. Myelinolysis also rarely occurs due to chronic alcoholism, liver failure, following liver transplantation, malnutrition, and dialysis, etc. ,, Extrapontine sites of involvement are mainly seen in basal ganglia, cortical/subcortical white matter, external capsule and extreme capsule, etc. ,, We describe an uncommon case of isolated extrapontine myelinolysis following dialysis where early diagnosis and supportive treatment helped speedy recovery of the patient.
| Case report|| |
A 52-year-old female patient who is a known hypertensive with chronic kidney disease on maintenance hemodialysis developed a seizure attack (Generalized-tonic clonic type) immediately after the dialysis. The seizure attack lasted for 5 min, following which she had aphasia and deviation of mouth to left side. She had no previous history of epilepsy. On examination, the patient was delirious. There was upper motor neuron type of facial palsy. Other cranial nerve examination was unremarkable. Muscle power and tone were normal. Complete blood picture and serum electrolyte concentrations were within normal limits. Initial diagnosis of stroke was made and magnetic resonance imaging (MRI) was advised to confirm the same. MRI was performed on GE HDxt 3 Tesla machine which showed bilateral symmetrical diffusion restriction in centrum semiovale and corona radiata [Figure 1] and [Figure 2]. Axial susceptibility weighted images demonstrate no blooming suggestive of hemorrhagic areas [Figure 3]. Pons was normal. A diagnosis of extrapontine myelinolysis was made and the patient was supportively managed. There was rapid recovery from the facial palsy and other symptoms. She was discharged as her neurological condition was satisfactory.
|Figure 1: (a-d) Axial diffusion-weighted imaging and corresponding apparent diffusion coeffiient (e-h) images showing symmetrical diffusion restriction in bilateral centrum semiovale and corona radiata|
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|Figure 2: (a) Axial flid-attenuated inversion recovery and (b) diffusion weighted imaging showing normal pons|
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|Figure 3: (a and b) Axial susceptibility-weighted images demonstrate no blooming suggestive of hemorrhagic areas|
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| Discussion|| |
Isolated extrapontine osmotic demyelination (IEPM) is due to an imbalance of electrolytes. It can occur in patients who require frequent dialysis. Exact etiopathogenesis of this may be related to osmotic stress resulting from electrolyte disequilibrium. ,,,, Oligodendrocytes are highly susceptible to osmotic stresses. Myelin vacuolization followed by intramyelinitic splitting and disruption of myelin sheaths occur due to rapid osmolar fluctuations. , Kilinç et al. have described a case of normonatremic individual who developed osmotic myelinolysis. Similarly, our patient also had normal sodium levels and developed IEPM. , Clinical features of osmotic demyelination syndrome are variable, ranging from altered sensorium to quadriparesis and coma.  Imaging diagnosis within 24 h can detect diffusion restriction in central pons sparing the peripheral pons. This finding is relatively specific and differentiates this condition from pontine infarction. Lack of brain stem expansion differentiates it from brain stem glioma. , Diagnosing IEPM requires a high degree of suspicion. Symmetrical bilateral putaminal, cortical and subcortical hyperintensities in a hypo or normonatremic individual, one should consider differential of IEPM. Treatment is generally symptomatic and supportive. , In recent times, asymptomatic cases and cases showing complete recovery following osmotic demyelination syndrome have been described. However, it is important to note that prognosis ranges from complete recovery to death. , Neither clinical nor radiological findings can predict the outcome of osmotic demyelination syndrome. Treatment of this condition is unclear. Favorable response with steroids by intravenous immunoglobulins have been reported. ,
| Conclusion|| |
Isolated extrapontine myelinolysis is extremely rare in setting of hemodialysis. Spontaneous resolution can occur without any treatment. However, it is important recognize this condition early for assessing prognosis, symmetrical hyperintensities in cortex and which resolve in subsequent MR scans are a clue in diagnosing this condition.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]