Magnesium Deficiency: Risks, Diagnosis, and Links to Other Pathologies

Introduction: The Role of Magnesium in the Body

Magnesium is one of the most essential minerals involved in hundreds of biochemical reactions in the body. It plays a key role in muscle and nervous system function, blood sugar regulation, blood pressure control, as well as bone formation and DNA synthesis. Despite its critical importance, magnesium deficiency, or hypomagnesemia, can be difficult to diagnose due to the nonspecific nature of symptoms and the complexity of assessing its levels in tissues.

Hypomagnesemia: Prevalence and Risks in Specific Groups

Although magnesium deficiency can occur in the general population, there are high-risk groups. For example, in patients undergoing peritoneal or hybrid dialysis, hypomagnesemia is a relatively common phenomenon. A study conducted in Japan showed that the prevalence of hypomagnesemia (serum magnesium level ≤ 1.5 mg/dL) was 6.2% among patients on peritoneal dialysis alone [5].

Serum magnesium level is an important indicator, and its decrease can be associated with serious consequences. In dialysis patients, hypomagnesemia is associated with an increased risk of developing atrial fibrillation [5]. This underscores the need for regular monitoring of magnesium levels in such patients and timely correction of deficiency to prevent cardiac complications.

Magnesium and Neurological Risks: When Treatment Can Harm

Magnesium, particularly in the form of magnesium sulfate, is used in medicine to treat various conditions, including the prevention of seizures in pregnant women with preeclampsia. However, like any active substance, it has its contraindications and risks. In some cases, the use of magnesium can lead to serious complications.

For example, in patients with myasthenia gravis — an autoimmune disease characterized by muscle weakness — the administration of magnesium sulfate can trigger a myasthenic crisis [8]. This is a condition in which there is a sharp worsening of muscle weakness, including the respiratory muscles, which can be life-threatening. In one case, a 37-year-old woman at 19 weeks of pregnancy with myasthenia gravis developed a myasthenic crisis after intravenous administration of magnesium sulfate for suspected preeclampsia [8]. This case highlights that in the presence of myasthenia gravis, alternative treatment methods for seizure prevention must be considered to avoid magnesium-induced exacerbation of the disease [8].

Non-obvious Symptoms: The Importance of Differential Diagnosis

Symptoms of deficiency in many micronutrients can be nonspecific and mimic other diseases, which complicates timely diagnosis. Although the presented scientific publications do not describe a wide range of general symptoms of magnesium deficiency, they vividly demonstrate how the lack of other important micronutrients, such as vitamin B12, can manifest with diverse and sometimes misleading signs that require thorough diagnosis.

Vitamin B12 Deficiency: Masks for Other Diseases

• Imitation of Addison's Disease: Severe vitamin B12 deficiency can clinically resemble Addison's disease, manifesting as hyperpigmentation of the skin and mucous membranes, despite normal adrenal function. A 34-year-old woman with fatigue, unintentional weight loss (about 20 kg), and mucocutaneous hyperpigmentation was misdiagnosed with primary adrenal insufficiency. Laboratory tests revealed severe cobalamin (vitamin B12) deficiency with macrocytic anemia and signs of intramedullary hemolysis, while adrenal function was preserved. After vitamin B12 replacement therapy, the symptoms gradually resolved [1].
• Skin Hyperpigmentation and Neurological Disorders: In rare cases, skin hyperpigmentation may be the only initial manifestation of vitamin B12 deficiency, which is easily overlooked and leads to delayed diagnosis. A 32-year-old man from Ghana experienced progressive darkening of the skin on his hands, palms, and soles for 4 years, followed by the development of an unsteady gait. A neurological examination revealed weakness in the lower extremities, sensory disturbances, and ataxia. Laboratory tests confirmed a severe vitamin B12 deficiency [2].
• Movement Disorders and Cognitive Impairment: Vitamin B12 deficiency can lead to cognitive impairment, optic neuropathy, sensorimotor polyneuropathy, and subacute combined degeneration of the spinal cord. In rare cases, it can cause extrapyramidal movement disorders such as chorea. A 66-year-old man with an acute onset of choreoathetoid symptoms was found to have a significant vitamin B12 deficiency. After vitamin B12 replacement therapy, the dyskinesia disappeared [3]. Cases of acute reversible cognitive decline due to B12 deficiency, accompanied by changes on brain MRI, have also been described [4].

Gastritis and Anemia

Collagenous gastritis is a rare chronic inflammatory disease of the stomach with nonspecific symptoms such as epigastric discomfort, anorexia, dizziness, and fatigue. It is often accompanied by severe iron-deficiency anemia. A 21-year-old woman with these symptoms and anemia was diagnosed with collagenous gastritis. Although treatment with iron and proton pump inhibitors improved symptoms and hematological parameters, histological changes persisted [6]. This example shows how rare gastroenterological diseases can manifest with systemic symptoms, including anemia, requiring comprehensive diagnosis.

Conclusion: A Comprehensive Approach to Diagnosis

As seen from the presented cases, deficiencies in important micronutrients and rare diseases can manifest in extremely diverse and nonspecific ways. This underscores the critical importance of thorough history taking, a complete physical examination, and comprehensive laboratory diagnostics. When magnesium deficiency or other disorders are suspected, especially in patients with chronic diseases or unclear symptoms, an individual approach and consultation with a specialist are necessary for an accurate diagnosis and the prescription of adequate treatment.

Sources

1. Addison-like Clinical Phenotype Without Adrenal Insufficiency: A Rare Manifestation of Pernicious Anemia. (JCEM case reports, 2026) PubMed
2. Skin Hyperpigmentation as Initial Manifestation of Vitamin B₁₂ Deficiency: A Case of Delayed Diagnosis With Late-Onset Subacute Combined Degeneration of the Cord. (Case reports in medicine, 2026) PubMed
3. Case Report: Reversible chorea arising from severe vitamin B12 deficiency due to autoimmune gastritis: a comprehensive case study. (Frontiers in nutrition, 2025) PubMed
4. Acute reversible cognitive dysfunction due to vitamin B12 deficiency: A case report with rare magnetic resonance imaging findings. (The Journal of international medical research, 2026) PubMed
5. Hypomagnesemia in peritoneal and hybrid dialysis: prevalence, predictors, and association with atrial fibrillation. (Clinical and experimental nephrology, 2026) PubMed
6. Collagenous gastritis: a rare case in young adult with iron deficiency anemia. (Revista espanola de enfermedades digestivas, 2026) PubMed
7. Therapeutic Effect and Side Effects of Pharmacotherapy in Patients With Parkinson Disease and Myasthenia Gravis: A Systematic Review of Case Reports and Case Series Studies. (Clinical therapeutics, 2024) PubMed
8. Magnesium Sulfate-Induced Myasthenic Crisis in Pregnancy: A Case Report. (Cureus, 2026) PubMed

Disclaimer: The information presented in this article is for reference purposes only and should not be used for self-diagnosis or self-treatment. Always consult a qualified medical professional for an accurate diagnosis and an individual treatment plan.