Proton pump inhibitor-induced hypomagnesemia, a rare cause of reversible delirium: A case report with literature review

Rationale: Hypomagnesemia is associated with multiple electrolyte disturbances such as hypokalemia, hypocalcemia and hypoparathyroidism. Proton pump inhibitors (PPIs) are widely used in gastrointestinal disorders and are generally considered safe by clinicians. However, it is unusual side effect of hypomagnesemia is potentially under-recognized. Delirium is usually thought to be a clue of cerebrovascular disease, and the association between delirium and hypomagnesemia is unexpected. We describe a patient used PPI with hypomagnesemia showed normal parathyroid hormone (PTH) despite hypocalcemia and reversible delirium. To enhance clinicians' vigilance, we performed a literature review on cerebellar syndromes due to hypomagnesemia.

Patient concerns: A 74-year-old woman was admitted to our hospital with intermittent nausea, vomiting, hand tremors, and delirium.

Diagnosis: Laboratory analysis showed hypokalemia, hypomagnesemia, and normal parathyroid hormone despite hypocalcemia, physical examination showed horizontal nystagmus and the brain MRI was negative. Surprising, detailed medical history revealed that the etiology was the usage of omeprazole.

Interventions: Omeprazole was discontinued and oral supplementation with magnesium, calcium, and potassium was administered.

Outcomes: Delirium quickly disappeared and the serum potassium, magnesium, and calcium levels gradually normalized; at discharge, nystagmus gradually disappeared, and plasma electrolyte levels were stable at follow-up.

Lessons: Hypomagnesemia is associated with a variety of neurological symptoms up to life-threatening conditions if left untreated; as Mg is not present in routine electrolyte panels, hypoparathyroidism, hypokalemia, and delirium may be a clue, and physicians must be alert to consider PPI as a potential cause of unexplained hypomagnesemia, and timely treatment to avoid sequelae.