IIH typically affects infants and pediatric patients with a syndrome characterized by severe hypercalcemia, hypercalciuria, suppressed parathyroid hormone level and nephrolithiasis.
The elevated 1,25(OH)<sub>2</sub>D levels in turn result in hypercalciuria due to enhanced intestinal calcium absorption and reduced parathyroid hormone (PTH)-dependent calcium-reabsorption in the distal renal tubules, leading to the development of kidney stones and/or nephrocalcinosis in approximately half of the individuals with HHRH.
The criteria for the diagnosis of NPHPT were as follows: serum PTH above the reference range (11-65 pg/mL), normal albumin-corrected serum calcium concentrations, normal 24-h urinary calcium excretion, serum 25OHD above 30 ng/mL, estimated GFR (MDRD) above 60 mL/min/1.73 m2 (with the exclusion of medications such as thiazide diuretics, lithium, bisphosphonates, and denosumab), a history of clinical symptoms of urolithiasis, and a family history of kidney stones.
In this review, composition of kidney stones, its prevalence/incidence, explanation of pathophysiological mechanisms and role of various factors; urinary pH, uric acid, parathyroid hormone, citrate, oxalate, calcium and macromolecules; osteopontin, matrix Gla protein, kidney injury molecules, urinary prothrombin fragment-1, Tamm-Horsfall protein, inter-α-inhibitors, have been discussed in detail.
Concerning the kidney, the most common consequences of excessive parathyroid hormone secretion are hypercalciuria and kidney stones; however, the exact pathogenesis of urinary stone formation is still unknown.
Patients with a history of nephrolithiasis or a suspected metabolic bone disease are increasingly being identified with elevated PTH concentrations in the setting of consistently normal serum and ionized calcium concentrations.
In multivariable analysis, higher preoperative calcium (odds ratio [OR] 1.7, 95% confidence interval [CI] 1.1-2.5), higher PTH (OR 1.0, 95% CI 1.0-1.0), and kidney stones (OR 3.0, 95% CI 1.1-8.2) were independently associated with HC.
Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications).
Patients with silent stones had higher parathyroid hormone (PTH) and lower 25OH-vitamin D (25OHD) levels and more frequently experienced microlithiasis than patients with symptomatic renal stones.
We performed mutational screening of CYP24A1 gene in a cohort of 12 Italian patients: 8 children with nephrocalcinosis, hypercalcemia and PTH levels <10 pg/ml and 4 adult patients with nephrolithiasis, mild hypercalcemia and PTH levels <10 pg/ml from 11 unrelated Italian families.
The 282D variant was not associated with serum calcium, phosphate, creatinine, or PTH levels or with bone mineral density, fractures, or renal stones in the PHPT group.
Here we describe a 29-year-old man with a history of childhood rickets who presented with increased renal phosphate clearance leading to hypophosphatemia, hypercalciuria, low serum parathyroid hormone (PTH), elevated serum 1,25-dihydroxyvitamin D (1,25(OH)2D) and recurrent nephrolithiasis.
Probands had recurrent nephrolithiasis, chronic hypercalcaemia with depressed parathyroid hormone (PTH) and increased 1,25(OH)(2)D levels; carriers had nephrolithiasis (two of six), hypercalciuria (two of six) and high or normal-high 1,25(OH)(2)D (four of four).
On follow-up, hypercalcemia with high parathyroid hormone (PTH) levels was detected, associated with nephrolithiasis and low bone mineral density in the spine and hip.
In PHPT patients, only R990G polymorphism was associated with disease parameters; in comparison with R/R, R/G+G/G patients showed lower mean serum parathyroid hormone (PTH) and phosphate levels (139.9 +/- 62.2 vs 199.9 +/- 136.3 pg/ml, P < 0.05 and 0.69 +/- 0.12 vs 0.81 +/- 0.18 mmol/l, P = 0.031 respectively), higher mean 24-h urine calcium concentration and calcium excretion (9.05 +/- 2.05 vs 6.77 +/- 4.31 mmol/24 h, P = 0.012 and 67 +/- 20 vs 51 +/- 26 mumol/l GF, P = 0.039), and increased prevalence of nephrolithiasis (90.0 vs 44.2%, P = 0.007).