Bilateral internuclear ophthalmoplegia as first manifestation of extra pontine myelinolysis

Extrapontine myelinolysis (EPM) is a rare clinical entity affecting anterior basal ganglia. This is one of the osmotic demyelination syndromes. It occurs due to rapid correction of hyponatremia and also rarely occurs in alcoholics. It generally presents with extrapyramidal symptoms. We here report a case of EPM in a 13 year old boy presenting with bilateral internuclear ophthalmoplegia and ptosis. The patient also had generalised weakness, but no psychiatric symptoms. The patient slowly recovered over six months. EPM can affect any age group, although the elderly are more likely to be affected due to frequent electrolyte abnormalities. Ocular movement disorders or brainstem signs are rarely reported in EPM. When present, it can create diagnostic confusion with multiple sclerosis. We believe this is the first report of this entity from India. The relevant literature regarding brainstem manifestations in myelinolysis syndromes is also discussed, along with the radiological findings.