Central pontine myelinolysis
Central pontine myelinolysis, is a rare disorder of pontine white matter.
Some cases of inordinately rapid hyponatremia treatment have been associated with osmotic demyelination syndrome (which includes central pontine myelinolysis (CPM) 1) and extrapontine myelinolysis, as well as other areas of cerebral white matter.
First described in alcoholism 2) producing insidious flaccid quadriplegia, mental status changes, and cranial nerve abnormalities with a pseudobulbar palsy appearance. In one review 3) no patient developed CPM when treated slowly.
And yet, the rate of correction correlates poorly with CPM; it may be that the magnitude is another critical variable 4). Features common to patients who develop CPM are 5)
● delay in the diagnosis of hyponatremia with resultant respiratory arrest or seizure with probable hypoxemic event
● rapid correction to normo-or hypernatremia(>135mEq/L) within 48 hours of initiating therapy
● increase of serum sodium by >25 mEq/L within 48 hours of initiation of therapy
● over-correcting serum sodium in patients with hepatic encephalopathy
● NB: many patients developing CPM were victims of chronic debilitating disease, malnourishment, or alcoholism and never had hyponatremia. Many had an episode of hypoxia/anoxia 6)
● presence of hyponatremia >24 hrs prior to treatment 7).
