Metabolic disorders: stones as first clinical manifestation of significant diseases

Metabolic syndrome, type 2 diabetes, and primary hyperparathyroidism are metabolic disorders that should deserve a special focus in renal stone patients as a pathogenic link is established with some stone components. Indeed, an acidic urinary pH due to a decreased ammonium bioavailability explains the high prevalence of uric acid stones in patients with metabolic syndrome or diabetes and, primary hyperparathyroidism induced hypercalciuria increases the risk of calcium phosphate stones.

We report here four clinical cases of renal stone patients with metabolic disorders encountered in a daily practice. Clinical and metabolic findings altogether with stone analysis components presented here, illustrate relevant pathophysiological links.

24 hours urine evaluation and stone analysis which includes both morphological typing and infrared spectroscopy, are key diagnostic steps for early recognition of metabolic disorders. Metabolic screening allows diet related stone identification, points out stone risk factors and identifies patients'comorbidity. The occurrence of nephrocalcinosis with or without chronic renal failure should require a more detailed metabolic evaluation in order to identify uncommon etiologies such as renal tubular acidosis.