From the Research
Based on the clinical picture of hypercalcemia with suppressed PTH, normal vitamin D, and a family history of hypercalcemia, I recommend testing for familial hypocalciuric hypercalcemia (FHH) by measuring the calcium-to-creatinine clearance ratio, as this condition is characterized by hypercalcemia, relative hypocalciuria, and inappropriately normal or elevated PTH levels, as described in the study by 1. The clinical presentation of hypercalcemia with low PTH levels and a family history of hypercalcemia suggests FHH, which is a benign condition with minimal complications, as noted in the study by 2. Key features of FHH include:
- Hypercalcemia
- Relative hypocalciuria
- Inappropriately normal or elevated PTH levels
- Family history of hypercalcemia
- Benign course with minimal complications To confirm the diagnosis of FHH, I recommend:
- Measuring the calcium-to-creatinine clearance ratio
- Genetic testing for calcium-sensing receptor (CaSR) mutations, which are characteristic of FHH, as described in the study by 3
- Comprehensive metabolic panel to assess renal function
- Complete blood count
- Thyroid function tests If these tests are unrevealing, consider testing for rarer causes of non-PTH mediated hypercalcemia, such as:
- Vitamin A toxicity
- Medications (thiazides, lithium)
- Granulomatous diseases, as described in the study by 4
- Infections, such as histoplasmosis, as described in the study by 5 It is essential to distinguish FHH from primary hyperparathyroidism, as the treatment and management of these conditions differ significantly, as noted in the study by 1.