Movement disorders and the osmotic demyelination syndrome.

With the advent of MRI, osmotic demyelination syndromes (ODS) are increasingly recognised to affect varied sites in the brain in addition to the classical central pontine lesion. Striatal involvement is seen in a large proportion of cases and results in a wide variety of movement disorders. Movement disorders and cognitive problems resulting from ODS affecting the basal ganglia may occur early in the course of the illness, or may present as delayed manifestations after the patient survives the acute phase. Such delayed symptoms may evolve over time, and may even progress despite treatment. Improved survival of patients in the last few decades due to better intensive care has led to an increase in the incidence of such delayed manifestations of ODS. While the outcome of ODS is not as dismal as hitherto believed - with the acute akinetic-rigid syndrome associated with striatal myelinolysis often responding to dopaminergic therapy - the delayed symptoms often prove refractory to medical therapy. This article presents a review of the epidemiology, pathophysiology, clinical features, imaging, and therapy of movement disorders associated with involvement of the basal ganglia in ODS. A comprehensive review of 54 previously published cases of movement disorders due to ODS, and a video recording depicting the spectrum of delayed movement disorders seen after recovery from ODS are also presented.