Related Experiment Videos
Familial hypocalciuric hypercalcemia: description of a new kindred with emphasis on its difference from primary
Insights
Familial hypocalciuric hypercalcemia (FHH) patients exhibit elevated serum calcium but significantly lower urinary calcium excretion compared to primary hyperparathyroidism (PHP). This distinction aids in diagnosing these related hypercalcemic disorders.
Area of Science:
- Endocrinology
- Nephrology
- Genetics
Background:
- Differentiating familial hypocalciuric hypercalcemia (FHH) from primary hyperparathyroidism (PHP) is crucial for accurate diagnosis and management.
- Both conditions involve hypercalcemia, but present with distinct clinical and biochemical profiles.
Observation:
- This study compared four FHH patients from two generations with six PHP patients and controls.
- FHH patients were asymptomatic, whereas PHP patients experienced recurrent renal stones.
- Key phosphocalcic balance elements were measured in blood and urine under various conditions.
Findings:
- Serum calcium was slightly elevated in FHH compared to PHP (11.90 vs 11.37 mg/dl).
- Serum phosphorus, parathyroid hormone, and 1,25(OH)2D levels were similar between FHH and PHP groups.
- Crucially, urinary calcium excretion (fasting, post-calcium load, and 24-hour) was significantly lower in FHH patients than in PHP patients (p < 0.001).
Implications:
- Lower urinary calcium excretion is a key differentiator for FHH, even with similar serum calcium and PTH levels.
- These findings support the use of urinary calcium measurements in distinguishing FHH from PHP.
- Accurate differentiation is essential for appropriate clinical management and genetic counseling.
Abstract:
In order to better understand the difference between familial hypocalciuric hypercalcemia (FHH) and primary hyperparathyroidism (PHP), 4 adults with this disease (FHH(+], from the same kindred, and spanning 2 generations, were compared with 6 patients with PHP, 10 normal controls (N) and 3 unaffected members of the same kindred (FHH(-]. Clinically speaking, the FHH(+) patients were asymptomatic while those with PHP had recurring renal stones. Various phosphocalcic balance elements were measured in blood and urine, in a fasting state, following oral loading of 1 g calcium, as well as in 24-hour urine specimens. Serum calcium levels were slightly higher (11.90 +/- .14 vs 11.37 +/- .24 mg/dl; p less than .05), in patients with FHH(+), but serum phosphorus (2.47 +/- .38 vs 2.88 +/- .40 mg/dl), serum parathyroid hormone (301 +/- 147 vs 291 +/- 224 pg/ml) and serum 1,25(OH)2D (52.8 +/- 6.7 vs 55.0 +/- 12.0 pg/ml) values were similar to those observed in patients with PHP. Urinary calcium present in FHH(+), while fasting (.064 +/- .043 mg/100 ml G.F.), after the calcium loading (.150 +/- .071) and in the 24-hour specimen (.089 +/- .016), was below the 95% confidence limit of values obtained in patients with PHP (.225 +/- .026, p less than .001; .413 +/- .066, p less than .001; 314 +/- .080, p less than .001), but similar to those obtained in N and FHH(-).(ABSTRACT TRUNCATED AT 250 WORDS)