D. Osmotic demyelination syndrome
This patient’s MRI demonstrated T2 hyperintensity of the pons and the surrounding basal ganglia diagnostic for osmotic demyelination syndrome (ODS). ODS is a rare neurologic sequela of osmotic stress, and in this case is associated with poorly controlled diabetes. Only 106 pediatric cases have been reported between 1960-2018. Classically, symptoms are delayed 2-6 days after a rapid correction of chronic hyponatremia. Other associations include:
- Chronic alcoholism
- Liver transplant
- Poorly controlled diabetes mellitus
- Diabetes insipidus
- Renal failure
- Refeeding syndrome
- Burns
ODS clinical manifestations are varied and include dysarthria, dysphagia, quadriparesis/paraparesis, behavioral disturbances, movement disorders, seizures, and/ altered mental status. Osmotic myelinolysis is usually seen in areas of the brain containing both gray and white matter, such as the pons and basal ganglia. MRI is the diagnostic test of choice. In 46% of patients there are pontine findings (ie. central pontine myelinolysis). 28% of patients have extrapontine findings, and 26% of patients have pontine and extrapontine findings. Treatment is supportive with a possible role for IVIG and steroids in pediatric patients. Complete neurologic recovery occurs in 60% of pediatric patients.
A brainstem cerebrovascular accident would involve a specific watershed area with associated ipsilateral cranial nerve palsies and contralateral hemiparesis. Acute disseminated encephalomyelitis would involve multiple, asymmetric, and typically bilateral signal abnormalities throughout the brain and is classically associated with fever and meningeal signs. Cerebral edema is associated with acute diabetic ketoacidosis or hyperosmolar hyperglycemic state. And finally a pontine glioma would demonstrate infiltration or a mass effect.
To date the patient continues to have a wide-based gait and dysmetria two months after the initial presentation. She is able to ambulate short distances with support, otherwise she uses a wheel chair. There has been slight improvement with regular physical therapy. Confusion and altered mental status has resolved. She has been started on gabapentin for tingling and increased sensitivity in the bilateral lower extremities.
References
Bansal LR, Zinkus T. Osmotic Demyelination Syndrome in Children. Pediatr Neurol. 2019;97:12‐17. doi:10.1016/j.pediatrneurol.2019.03.018
Donnelly H, Connor S, Quirk J. Central pontine myelinolysis secondary to hyperglycaemia. Pract Neurol. 2016;16(6):493‐495. doi:10.1136/practneurol-2016-001389
Fasano A, Cavallieri F, Mandrioli J, Chiari A, Nichelli P. Central pontine myelinolysis and poorly controlled diabetes: MRI’s hints for pathogenesis. Neurol Sci. 2018;39(1):193‐195. doi:10.1007/s10072-017-3117-0
Kamath M, Manjunath S. Idiopathic Central Pontine and ExtrapontineMyelinolysis in a Child. J Pediatr Neurosci. 2019;14(2):97‐99. doi:10.4103/jpn.JPN_158_18