Authors: Pinehas N L et al.
Cureus, 18(1): e101584, January 2026 DOI: 10.7759/cureus.101584
Summary
This case report describes severe magnesium toxicity in a 22-year-old pregnant patient treated for eclampsia using a standard intramuscular Pritchard magnesium sulfate regimen in the setting of preeclampsia-related renal dysfunction. Despite receiving guideline-recommended dosing, impaired renal excretion led to progressive hypermagnesemia with multisystem involvement, including altered mental status, loss of deep tendon reflexes, respiratory failure, acute kidney injury, HELLP syndrome, and posterior reversible encephalopathy syndrome (PRES).
The patient received a total of 34 g of magnesium sulfate within 24 hours across multiple facilities before transfer to a tertiary hospital. On arrival, she was oliguric, hypoxic, encephalopathic, and had absent patellar reflexes with markedly elevated serum creatinine and magnesium levels. Initial management focused on magnesium antagonism with intravenous calcium gluconate, seizure control, and stabilization. Due to multiorgan dysfunction, an emergency cesarean delivery was performed under general anesthesia without neuromuscular blockade. The neonate required resuscitation and NICU admission but survived.
Postoperatively, the patient deteriorated metabolically, with worsening renal failure, metabolic acidosis, and persistent hypermagnesemia. Mechanical ventilation and intermittent hemodialysis were required, leading to normalization of magnesium levels, recovery of renal function, and eventual liberation from ventilatory support. She was discharged without permanent neurological deficits.
The report emphasizes that magnesium toxicity can occur even with standard dosing when renal clearance is impaired, particularly in low-resource settings where laboratory monitoring and ECG surveillance may be limited. Early recognition based on clinical findings and prompt escalation to dialysis were key to avoiding catastrophic maternal outcomes.
Key Points
• Magnesium toxicity can occur despite standard Pritchard dosing in patients with renal dysfunction
• Clinical signs (loss of reflexes, respiratory depression, altered mental status) may precede laboratory confirmation
• Calcium gluconate is essential for acute stabilization, but dialysis may be required when renal failure coexists
• Obstetric anesthesia must anticipate prolonged neuromuscular and respiratory effects of hypermagnesemia
• Low-resource settings magnify the risk due to limited monitoring and delayed diagnosis
What You Should Know
For anesthesiologists and obstetric teams, this case reinforces that “standard dose” does not mean “safe dose” in preeclamptic patients with renal impairment. Reliance on clinical monitoring—particularly deep tendon reflexes, respiratory rate, and mental status—is critical when serum magnesium levels are unavailable or delayed. In high-risk patients, lower-dose magnesium regimens or alternative protocols should be considered, and early nephrology involvement for dialysis can be lifesaving.
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