Central Pontine Myelinolysis
Original Editor - Wendy Walker
Top Contributors - Wendy Walker, Laura Ritchie, Kim Jackson, Lucinda hampton, WikiSysop, Admin, Naomi O'Reilly and Aminat Abolade
Introduction[edit | edit source]
Central pontine myelinolysis (CPM) is a component of osmotic demyelination syndrome (ODS), characterized by damage to regions of the brain (most commonly pontine white matter tracts) after rapid correction of metabolic disturbances such as hyponatremia (low amounts of sodium in the blood)
- Central pontine myelinolysis (CPM) was first described in 1959 by Adams and his colleagues in a report of four patients with pseudobulbar palsy and quadriplegia.
- The initial cases were seen in patients with alcohol use disorder and malnutrition.
- Subsequent cases showed a link with rapid sodium correction.
- CPM has since been reported in cases of severe burns, liver transplantation, anorexia nervosa and hyperemesis gravidarum, and hyperglycemic states.
- Clinical features of CPM typically begin to appear within several days after rapid correction of hyponatremia. Clinical manifestations vary and can range from encephalopathy to coma and death.[1]
Mechanism of Injury / Pathological Process[edit | edit source]
Central pontine myelinolysis is a concentrated, frequently symmetric, noninflammatory demyelination within the pons. The area involved is usually confined to the basal part of the pons but occasionally involves the tegmentum also
The Pons is situated in the brainstem. It lies above the medulla, below the midbrain and anterior to the cerebellum.
It is one of the demyelinating conditions and was first described by Adams et al in 1959.[2] In at least 10% of patients with central pontine myelinolysis, demyelination also occurs in extrapontine regions, including the mid brain, thalamus, basal nuclei and cerebellum. The exact mechanism that strips the myelin sheath is unknown.
Central pontine myelinolysis occurs most often as a complication of treatment of patients with profound, life-threatenin-g hyponatremia (low sodium) and is a consequence of a rapid rise in serum tonicity following treatment in individuals with chronic, severe hyponatraemia who have made intracellular adaptations to the prevailing hypotonicity.
In some cases, demyelination occurs outside the pons too; cases which include extrapontine demyelination are labelled "osmotic demyelination syndrome", "extra pontine myelinosis" or "osmotic myelinosis".[3]
Microscopically the lesion shows degeneration and loss of oligodendrocytes with preservation of axons unless the lesion is very advanced.
Clinical Presentation[edit | edit source]
Clinically CPM presents in a biphasic pattern: 1st phase = acute encephalopathy, caused by the electrolyte abnormalities. Once treatment is given causing rapid reversal of this abnormality, the patient improves for 2 to 3 days before progressing onto the classic CPM features. These consist of:
Causes[edit | edit source]Conditions predisposing patients to central pontine myelinolysis include alcoholism, liver disease, malnutrition and hyponatraemia (an electrolyte disturbance in which the sodium ion concentration in the plasma is lower than normal). CPM may occur following liver transplantation surgery. Burn patients may develop CPM and it can also occur with Wilson disease and neoplasia. Diagnostic Procedures[edit | edit source]
|