# Hypocalcemia Revisited: Thinking Outside the Box!

## TL;DR

A 62-year-old man with chronic hypocalcemia was diagnosed with pseudohypoparathyroidism type 1b after standard treatments failed.

## Contribution

The paper highlights the importance of genetic testing in diagnosing pseudohypoparathyroidism when hypocalcemia persists despite treatment.

## Key findings

- Persistent hypocalcemia despite calcium and vitamin D supplementation led to a PHP1b diagnosis via genetic testing.
- Alfacalcidol treatment showed a positive response, indicating parathyroid hormone resistance.
- The case underscores the need for systematic evaluation to identify rare causes of chronic hypocalcemia.

## Abstract

This case report details the presentation of a 62-year-old man with a background of hypothyroidism, hypertension, and chronic kidney disease (CKD) who experienced fatigue with acute-on-chronic hypocalcemia. Despite receiving oral calcium carbonate with vitamin D3 (cholecalciferol) supplementation in primary care, persistent hypocalcemia in the absence of significant renal impairment and a positive response to alfacalcidol (1α-hydroxycholecalciferol) prompted further investigation into genetic causes. A final diagnosis of pseudohypoparathyroidism type 1b (PHP1b) was confirmed through genetic studies. In cases of pseudohypoparathyroidism (PHP), appropriate monitoring and timely management are essential for patient safety and favorable outcomes. This case explores the systematic approach required in the assessment of chronic hypocalcemia to discern aetiology among a wider range of differentials.