Hyperthermia in Severe Hyponatremia: Causes and Clinical Approach

Primary Causes to Investigate

Infection is the most frequent precipitating factor for both hyperthermia and hyponatremia in hospitalized patients, with pneumonia, urinary tract infection, and sepsis being the leading causes 1, 2
Approximately one-third of patients admitted with acute illness will be hyperthermic within the first hours, and hyperthermia is associated with poor neurological outcomes due to increased metabolic demands 1, 2
Patients can be normothermic or even hypothermic despite infection due to peripheral vasodilation, and hypothermia when present is a poor prognostic sign 4

Obtain medication history to identify potential causative agents, and perform infectious workup including complete blood count, urinalysis, chest X-ray, blood cultures, and urine cultures 1, 2
Check creatine kinase to assess for rhabdomyolysis from drug-induced hyperthermia or severe hyponatremia 5, 6
Assess volume status through physical examination to guide hyponatremia management 8

For infection-related hyperthermia, initiate appropriate antimicrobial therapy based on suspected source, and implement measures to achieve normothermia 1, 2
For severe symptomatic hyponatremia, administer 3% hypertonic saline with a target correction of 6 mmol/L over 6 hours, but total correction must not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 8
The American College of Physicians recommends treating dehydration and elevated creatine kinase with IV fluids to prevent renal failure from rhabdomyolysis, although the specific guideline is not mentioned in the article, similar recommendations can be found in other clinical guidelines 3, 5, 6

Do not assume fever is always infectious in origin when a patient is on haloperidol or other antipsychotics—consider drug-induced causes early 3
Do not correct chronic hyponatremia faster than 8 mmol/L in 24 hours—overcorrection risks osmotic demyelination syndrome 8