Hypercalciuria with hypercalcemia

– Primary hyperparathyroidism: hypercalciuria caused mainly by increased bone resorption

– Granulomatous diseases (eg, tuberculosis, sarcoidosis, certain types of lymphoma): hypercalciuria caused by excessive synthesis of 1,25(OH)2D3

– Malignancy: bone metastases or increased bone resorption caused by secreted cytokines, synthesis of PTH and PTHrP by some types of cancer

Hypercalciuria without hypercalcemia

– Type 1 distal RTA: nonrespiratory acidosis causing decrease in citrate excretion and reducing reabsorption of calcium (increasing calcium excretion)

– Idiopathic hypercalciuria:

a) With increased calcium absorption: GI calcium absorption ~50% higher than in general population

b) With increased calcium resorption: increased bone resorption without clinically relevant bone disease; increased bone turnover

c) Renal

Hypocitraturia

– Type 1 distal RTA: nonrespiratory acidosis causing decrease in citrate excretion and reducing reabsorption of calcium (increasing calcium excretion)

– Nephrolithiasis associated with chronic diarrhea: chronic diarrhea with loss of bases causing acidosis; may also cause hypokalemia

– Intracellular acidosis caused by chronic hypokalemia: chronic hypokalemia leading to intracellular acidosis, which directly causes hypocitraturia

Hyperoxaluria

– Enzyme defects causing increased synthesis of oxalate

– Acquired: excessive dietary oxalate intake, long-term administration of vitamin C, low-calcium diet (lack of binding of oxalate by calcium in GI tract), chronic diseases of small intestine; bariatric bypass surgery

Cystinuria

Genetic defects of reabsorption of amino acids: cystine, ornithine, arginine, lysine; stones formed from the least soluble cystine

Alkaline urine

UTIs caused by urease-producing bacteria; degradation of urea causing increase in urine pH, which leads to precipitation of struvite stones

Hyperuricosuria

– Gout, Lesch-Nyhan syndrome: abnormalities of purine metabolism

– Myeloproliferative neoplasms and other malignancies: increased degradation of nucleic acids

– Excess dietary purine intake

– Treatment with uricosuric agents

– Idiopathic