Vitamin D2026

Case Report: Unusual electrolyte changes in primary hyperparathyroidism-a call to suspect underlying Gitelman syndrome.

Shantha Dasili Wickramasinghe Aruna, Waidyatilleke Sasmitha Ravindu, Senevirathne Kanishka Piumi, Dhanushkar Ravindran et al. — Frontiers in endocrinology

Summary

This report describes a 74-year-old woman with an overactive parathyroid gland, a condition usually causing high blood calcium. However, she also presented with unusual low levels of potassium and magnesium, and surprisingly low calcium in her urine. These complex findings, along with vitamin D deficiency, led doctors to suspect an additional underlying kidney disorder called Gitelman syndrome, even after treating the parathyroid issue.

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Key points

A patient with an overactive parathyroid gland showed unusual low potassium, low magnesium, and low calcium in her urine.
These unexpected electrolyte imbalances, combined with vitamin D deficiency, suggested an additional kidney condition.
Even after successful treatment for the overactive parathyroid gland, some electrolyte issues persisted, pointing to an underlying disorder like Gitelman syndrome.
This case highlights that complex electrolyte problems can have multiple causes beyond a single diagnosis.

What the study looked at

What question the study asked: This case report aimed to highlight that when a patient with an overactive parathyroid gland shows unusual electrolyte imbalances—specifically low potassium, low magnesium, and surprisingly low calcium in the urine—it should prompt doctors to consider other underlying conditions. It explored what these atypical findings, especially alongside vitamin D deficiency, might indicate. How it was studied (design/participants): This was a detailed observation of a single 74-year-old woman. Her medical team carefully documented her symptoms, conducted various blood and urine tests to measure electrolyte levels and hormone activity, and used imaging techniques to identify the parathyroid issue. They also monitored her response to surgery and subsequent treatments. What it found: The study found that despite having an overactive parathyroid gland (which usually causes high calcium in the blood and urine), the patient had low potassium, low magnesium, and unusually low calcium in her urine. She also had vitamin D deficiency. Even after successful surgery to remove the overactive parathyroid tissue and receiving vitamin D supplements, her low magnesium levels continued. This led the doctors to conclude that she likely had an additional, underlying kidney disorder, such as Gitelman syndrome, which affects how the kidneys manage electrolytes.

Dietary takeaway

This case highlights that complex electrolyte imbalances can stem from multiple health issues, including both hormonal problems and kidney function, with vitamin D status being one contributing factor. While this specific report doesn't offer direct dietary advice for the general public, it reinforces the importance of maintaining adequate vitamin D levels through sources like fatty fish, fortified foods, or safe sun exposure for overall health. It's crucial to remember that this is a single case study, and its findings may not apply broadly; always consult a healthcare professional for personalized health and dietary guidance.

Abstract

BACKGROUND: Primary hyperparathyroidism (PHPT) is commonly associated with hypercalcemia, hypophosphatemia, and hypercalciuria. Hypokalemia and hypomagnesemia are rare and indicate a complicated etiology. CASE PRESENTATION: We describe a 74-year-old woman who presented with metabolic encephalopathy and moderate dehydration. Biochemical examinations revealed a parathyroid crisis with severe hypercalcemia (4.18 mmol/L), hypophosphatemia, hypokalemic (2.5 mmol/L) metabolic alkalosis, severe hypomagnesemia (0.23 mmol/L), and a high level of intact parathyroid hormone (243.0 pg/mL). The electrolyte imbalances were resistant to proper hydration and electrolyte replacement. Markedly, urine analysis showed renal potassium and magnesium wasting and severe hypocalciuria (calcium-to-creatinine clearance ratio, 0.0093). The presence of this paradoxical hypocalciuria despite PHPT brought into question the possibility of an underlying renal tubulopathy or accompanying vitamin D deficiency. Vitamin D assay showed deficiency with a level of 14.2 ng/mL. Ultrasound neck and contrast-enhanced computed tomography of the neck showed a right thyroid lesion for which the patient underwent right hemithyroidectomy and parathyroidectomy. Histopathological examination revealed a parathyroid adenoma. Although the patient's hypercalcemia settled postoperatively, hypomagnesemia persisted despite vitamin D supplementation, which indicates the presence of underlying renal tubulopathy, likely Gitelman syndrome. CONCLUSION: This case emphasizes that persistent hypokalemia, hypomagnesemia, and unexpected hypocalciuria in patients with PHPT should prompt clinicians to suspect concurrent renal tubulopathies such as Gitelman syndrome.

View on PubMed →DOI: 10.3389/fendo.2026.1829964