Acute focal neurological deficits routinely trigger immediate stroke code protocols in emergency departments. However, non-vascular metabolic disturbances can produce identical clinical features. Clinicians must recognize that a hypomagnesemia stroke mimic can closely simulate acute cerebral ischemia. Patients presenting with sudden hemiparesis or aphasia often undergo urgent neuroimaging and thrombolysis assessments. Nevertheless, basic laboratory panels rarely measure magnesium during acute presentations. Consequently, severe magnesium deficiency remains an underdiagnosed etiology of acute focal deficits. A recent clinical report highlights this critical diagnostic vulnerability in a patient taking proton pump inhibitors and metformin. The patient developed acute hemiparesis and aphasia, which resolved completely following magnesium repletion. Therefore, physicians must maintain clinical suspicion for drug-induced electrolyte depletion during acute neurovascular evaluations.

Recognizing the Hypomagnesemia Stroke Mimic Presentation

Emergency physicians frequently encounter stroke mimics during acute clinical evaluations. In fact, mimics account for nearly thirty percent of all emergency stroke admissions. Typical mimics include epileptic seizures, complex migraines, functional neurological disorders, and hypoglycemia. However, hypomagnesemia presenting with isolated focal neurological deficits remains exceptionally rare and frequently overlooked.

In this recent case report, a patient presented with sudden unilateral motor weakness and severe aphasia. Because these symptoms pointed to middle cerebral artery occlusion, the team immediately suspected an acute stroke. However, emergency computed tomography and magnetic resonance imaging revealed no acute ischemic lesion. Furthermore, the patient had experienced prior unexplained transient neurological episodes that resolved spontaneously.

Notably, laboratory testing revealed severe hypomagnesemia as the sole underlying metabolic abnormality. Magnesium deficiency typically presents with generalized neuromuscular symptoms, including tetany, carpopedal spasms, tremors, and cardiac arrhythmias. Conversely, unilateral hemiparesis and cortical deficits represent distinctly atypical manifestations of magnesium depletion. Consequently, practitioners often dismiss metabolic causes when deficits follow a strict vascular distribution. Recognizing this presentation prevents unnecessary interventions and ensures prompt, appropriate treatment.

The Pharmacological Link: Long-Term PPI and Metformin Use

Common medications often induce significant metabolic disturbances that escape routine clinical detection. Specifically, prolonged use of proton pump inhibitors frequently impairs active gastrointestinal magnesium absorption. Chronic gastric acid suppression alters intestinal luminal pH, which suppresses transient receptor potential melastatin channels, particularly TRPM6 and TRPM7. Over time, this diminished intestinal uptake leads to profound systemic magnesium depletion.

Additionally, concurrent metformin therapy introduces further metabolic challenges. Metformin alters intestinal cation transport and gut motility, compounding the malabsorptive effects of acid suppression. Millions of patients globally take proton pump inhibitors and metformin concurrently for gastroesophageal reflux and type 2 diabetes. Furthermore, clinicians rarely order routine serum magnesium tests during chronic outpatient follow-up.

As a result, severe hypomagnesemia progresses silently until acute neurological symptoms emerge. In this documented case, long-term medication use directly contributed to life-threatening electrolyte exhaustion. Discontinuing the offending proton pump inhibitor or substituting a histamine-2 receptor antagonist typically normalizes gastrointestinal magnesium transport. Therefore, physicians must rigorously review chronic medications whenever patients present with unexplained transient neurological symptoms.

Pathophysiological Mechanisms Behind Focal Neurological Deficits

Magnesium plays a vital physiological role in maintaining normal neuronal stability and cerebrovascular tone. At the cellular level, magnesium blocks N-methyl-D-aspartate receptor channels in a voltage-dependent manner. When serum magnesium falls precipitously, this natural receptor blockade fails. Consequently, excessive calcium influx triggers neuronal hyperexcitability and neurotoxic cellular cascades.

Moreover, profound hypomagnesemia promotes localized cerebral vasoconstriction. Magnesium directly stabilizes vascular smooth muscle by regulating intracellular calcium exchange. Severe deficiency precipitates focal arterial vasospasm, which causes transient regional cerebral hypoperfusion without permanent infarction. This localized hypoperfusion explains why clinical symptoms can mimic a specific vascular territory syndrome, such as acute hemiparesis or aphasia.

In addition, severe magnesium depletion impairs neuronal sodium-potassium ATPase pump function. This enzymatic dysfunction destabilizes resting membrane potentials and promotes spreading cortical depression. When combined with subclinical regional microvascular vulnerability, metabolic exhaustion targets specific cortical networks disproportionately. Thus, focal deficits manifest instead of generalized encephalopathy. Fortunately, these pathophysiological disruptions remain functional and reversible before structural necrosis develops.

Diagnostic Challenges and Emergency Department Workup

Managing acute neurological deficits requires rapid, precise clinical evaluation under strict time constraints. Clinicians must quickly differentiate ischemic stroke from mimic conditions to avoid inappropriate thrombolysis. However, standard acute blood panels commonly exclude serum magnesium testing. Because stroke code algorithms prioritize speed, atypical metabolic mimics frequently bypass routine detection.

Consequently, clinicians may administer intravenous thrombolytic therapy to patients with pure metabolic deficits. Although thrombolysis in stroke mimics carries low intracranial hemorrhage risk, it incurs substantial unnecessary healthcare costs and patient anxiety. Furthermore, missed severe hypomagnesemia leaves patients vulnerable to fatal cardiac arrhythmias, including torsades de pointes.

Therefore, emergency departments should consider incorporating magnesium into routine hyperacute electrolyte panels. Advanced neuroimaging plays a decisive role in resolving diagnostic ambiguity. Specifically, diffusion-weighted magnetic resonance imaging demonstrates an absence of cytotoxic edema, which points toward non-ischemic etiologies. When neuroimaging does not match profound clinical deficits, clinicians must immediately investigate reversible metabolic disturbances. Notably, a detailed medication history provides vital clues that accelerate the correct diagnosis.

Therapeutic Reversal and Preventive Clinical Practice

Immediate electrolyte correction produces rapid and dramatic clinical improvement in severe hypomagnesemia. Intravenous administration of magnesium sulfate rapidly restores extracellular cation concentrations. As magnesium levels normalize, the physiological blockade of N-methyl-D-aspartate receptors returns, arresting excitotoxic signaling pathways.

Simultaneously, cerebral vascular tone normalizes as smooth muscle membranes stabilize. In this case, prompt intravenous magnesium infusion produced complete recovery from hemiparesis and aphasia. The patient regained baseline neurological function without any permanent functional deficits. Conversely, failure to replenish magnesium promptly can cause persistent deficits, refractory seizures, and secondary hypocalcemia.

Following acute intravenous therapy, clinicians must prescribe oral magnesium supplementation to replenish depleted intracellular stores. Intracellular repletion often requires several weeks of sustained therapy. In addition, clinicians must stop contributing medications like proton pump inhibitors to prevent recurrence. Primary care physicians should practice active deprescribing and monitor electrolytes periodically in patients requiring chronic acid suppression. Ultimately, heightened clinical vigilance enables physicians to cure this alarming condition swiftly and effectively.

Can severe hypomagnesemia cause focal deficits like hemiparesis and aphasia?

Yes, severe hypomagnesemia can produce focal deficits, including hemiparesis and aphasia. Depleted magnesium triggers localized cerebral vasospasm, impairs membrane potentials, and causes uncontrolled N-methyl-D-aspartate receptor activation. These pathophysiological alterations induce reversible regional hypoperfusion and focal cortical dysfunction that closely mimic acute ischemic stroke without causing permanent structural tissue damage.

Why does long-term proton pump inhibitor use cause magnesium depletion?

Proton pump inhibitors alter intestinal pH, which impairs active magnesium transport across the gut epithelium. Chronic acid suppression inhibits transient receptor potential melastatin channels, specifically TRPM6 and TRPM7. Over months or years, blunted intestinal absorption exhausts total body magnesium stores, especially when combined with medications like metformin or poor dietary intake.

How should clinicians manage acute stroke mimics caused by hypomagnesemia?

Clinicians must immediately administer intravenous magnesium sulfate under continuous cardiac monitoring to restore normal neurological function. Concurrently, clinicians should perform urgent neuroimaging to rule out true vascular occlusion. After acute symptoms resolve, patients require oral magnesium supplementation, electrolyte monitoring, and discontinuation of offending drugs like chronic proton pump inhibitors.

Disclaimer: This content is for informational and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here. The mentions of specific products or services do not constitute endorsement. Refer to the latest local and national guidelines for clinical practice.

References

Vidal Bankier D et al. Stroke mimic caused by severe hypomagnesemia: a case report and literature review. J Neurol. 2026 Sep 29. doi: 10.1007/s00415-026-14155-8. PMID: 42809124.

Pascarella A, Cutellè R, Cianci V, Gasparini S, Ferlazzo E. Severe hypomagnesemia mimicking acute stroke: a rare but overlooked mimic? Neurol Sci. 2025;46(9):4741-4743. doi: 10.1007/s10072-025-08215-6.

Shan M, et al. Stroke mimic in an acute rehabilitation unit patient with associated hypomagnesaemia. BMJ Case Rep. 2021;14(4):e239777. doi: 10.1136/bcr-2020-239777.

Tamura T, et al. Dilemma in the emergency setting: hypomagnesemia mimicking acute stroke. Case Rep Neurol. 2016;8(2):125-130. doi: 10.1159/000446864.