3274 patients were examined in the hospital with admission serum sodium of less than 120 mEq/l for the development of central pontine myelinolysis (CPM). Seven patients with CPM were identified; five developed CPM despite a sodium correction rate of less than or equal to 8 mEq/l/24 hours.
The current study suggest that in patients with severe hyponatremia, less than 120 mg/L sodium correction of less than 6 mg/L and initial 24 hours of hospitalization is associated with increased in the hospital and 30-day mortality and longer length of stay compared to correction greater than 10 mg/L per 24 hours. Similar to prior studies correction rates frequently exceeded guideline recommendations and the incidence of central pontine myelinolysis is infrequent.
Limiting the sodium correction rate was associated with higher mortality and longer length of stay. Whether the sodium correction rate influences neurologic complications needs further evaluation.
Published September26,2023 NEJM Evid 2023 https://evidence.nejm.org/toc/evid/2/10
ORIGINAL ARTICLE :Severe Hyponatremia Correction, Mortality, and Central Pontine Myelinolysis
Mortality was highest in patients with history of alcoholism and cancer. Patient's with admission Na<105 mEq/L were at the highest risk for CPM.
2013 US guidelines recommend a limit of 8 mg/L for patients at high risk ( sodium level less than or equal to 105 mEq/L, hypokalemia, alcoholism, malnutrition and advanced liver disease) . Lowering of 10 to 12 mg/L for patients at normal risk with chronic severe hyponatremia (less or equal than 120 mg/L.). At goal 24-hour correction rate of 4-6 mg/L is also recommended for individuals at high risk.
2014 European guidelines recommend limiting 24-hour correction rate to 10 mEq/L in patients with moderately symptomatic hyponatremia.
CPM has been reported among many patients with severe hyponatremia even when guidelines recommend correction was achieved and also has been described in patient with normal to mildly low sodium levels
Rate of sodium correction may be important for preventing some cases of ODS (Osmotic Demyelination Syndrome) . However etiologic categories of serum sodium and other potential risk predispositions also play an important role in the development of CPM.
