From the Guidelines
The patient's calcium level of 2.09 mmol/L indicates hypocalcemia, and I strongly recommend daily calcium and vitamin D supplementation to manage this condition, as suggested by the practical guidelines for managing adults with 22q11.2 deletion syndrome 1. The normal range for calcium levels is typically 2.20-2.60 mmol/L, and a level of 2.09 mmol/L is considered low. Hypocalcemia can be associated with fatigue, emotional irritability, abnormal involuntary movements, seizures, and cardiac arrhythmias, and may predispose to osteopenia/osteoporosis.
- Key considerations for managing hypocalcemia include:
- Regular investigations, including measurements of pH-corrected ionized calcium, magnesium, parathyroid hormone, and creatinine concentrations
- Daily calcium and vitamin D supplementation for all adults with 22q11.2DS
- Magnesium supplementation for those with hypomagnesemia
- Targeted monitoring of calcium concentrations at vulnerable times, such as peri-operatively, perinatally, or during severe illness
- Caution against over-correction, which can result in iatrogenic hypercalcemia, renal calculi, and renal failure, as noted in the study 1. It is essential to investigate the underlying cause of hypocalcemia, as it could result from vitamin D deficiency, hypoparathyroidism, kidney disease, or certain medications. Regular monitoring of calcium levels is necessary to ensure the effectiveness of supplementation. Calcium is essential for proper nerve and muscle function, blood clotting, and bone health, making correction of low levels important for overall health, as emphasized in the guidelines 1.
From the Research
Hypocalcemia Diagnosis and Management
- Hypocalcemia, defined as a serum calcium level less than 2.12 mmol/L, can be caused by various disorders, including hypoparathyroidism and vitamin D metabolism disruptions 2, 3.
- Symptoms of hypocalcemia can range from asymptomatic to life-threatening conditions, including neuromuscular irritability, tetany, and seizures 2, 3.
- Treatment and management options for hypocalcemia vary depending on the underlying disorder, and may include calcium and vitamin D supplementation, as well as replacement of parathyroid hormone (PTH) in cases of hypoparathyroidism 2, 3.
Calcium Homeostasis and Regulation
- Calcium homeostasis is maintained by the complex regulatory axes of PTH and vitamin D, and disorders that disrupt these axes can lead to hypocalcemia 2, 3.
- Calcium absorption and bioavailability are also important factors in maintaining calcium homeostasis, and can be influenced by dietary factors and nutrient sources 4.
- The evaluation of calcium absorption and bioavailability can be done using various methods, including calcium isotopes and absorption tests 4.
Differential Diagnosis of Hypocalcemia
- Hypocalcemia can be divided into two categories: hypocalcemia with low serum phosphate level, and hypocalcemia with normal to elevated serum phosphate level 5.
- The differential diagnosis of hypocalcemia requires a comprehensive approach, including physical and laboratory findings, medical history, and accompanying illnesses 5.
- Recent investigations have identified several causes of PTH-deficient hypoparathyroidism, including genetic abnormalities and parathyroid autoantibodies, which should be differentiated from idiopathic hypoparathyroidism 5.