Bone disease in medullary sponge kidney and effect of potassium citrate treatment.
OBJECTIVE
In medullary sponge kidney (MSK)-a common malformative renal condition in patients with calcium nephrolithiasis-hypercalciuria, incomplete distal renal tubular acidosis, and hypocitraturia are common. Clinical conditions with concomitant hypercalciuria and/or incomplete distal renal tubular acidosis are almost invariably associated with bone disease, making osteopathy highly likely in MSK, too. Patients with MSK have never been investigated for osteopathy; neither has the potential effect of potassium citrate administration (CA) on their urinary metabolic risk factors and on bone mineralization.


METHODS
These issues were retrospectively analyzed in 75 patients with MSK and primary stone risk factor (PSRF; hypercalciuria, hypocitraturia, hyperuricosuria, and/or hyperoxaluria) on an outpatient basis; 65 received CA (2.9 +/- 0.8 g/d), whereas 10 received only general "stone clinic" suggestions. The 24-h urinary excretion of calcium, phosphate, oxalate, uric acid, and citrate; morning urine pH; serum biochemistry; and bone mineral density were investigated at baseline and at the end of follow-up (78 +/- 13 and 72 +/- 15 mo in groups A and B, respectively).


RESULTS
CA led to a significant rise in urinary pH and citrate and decreased urinary calcium and phosphate (all P < 0.001). Patients with MSK and PSRF had reduced bone density. Bone density improved significantly in the group that was treated with oral CA.


CONCLUSIONS
Bone disease is very frequent in patients with MSK and concomitant PSRF. Long-term CA improves bone density. The concurrent effects of treatment on PSRF suggest that the subtle acidosis plays a pivotal role in bone disease and hypercalciuria in patients with MSK.
Fabris
Antonia
A
Division of Nephrology, Department of Biomedical and Surgical Sciences, University Hospital of Verona, Verona, Italy.
Bernich
Patrizia
P
Abaterusso
Cataldo
C
Marchionna
Nicola
N
Canciani
Chiara
C
Nouvenne
Antonio
A
Zamboni
Mauro
M
Lupo
Antonio
A
Gambaro
Giovanni
G
D015502:Absorptiometry, Photon; D000141:Acidosis, Renal Tubular / Q000188:drug therapy / Q000209:etiology; D000293:Adolescent; D000328:Adult; D015519:Bone Density / Q000187:drug effects; D001847:Bone Diseases / Q000150:complications* / Q000000981:diagnostic imaging / Q000517:prevention & control*; D004232:Diuretics / Q000008:administration & dosage*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D053565:Hypercalciuria / Q000188:drug therapy / Q000209:etiology; D008297:Male; D007691:Medullary Sponge Kidney / Q000150:complications* / Q000188:drug therapy*; D053040:Nephrolithiasis / Q000150:complications / Q000188:drug therapy; D010710:Phosphates / Q000652:urine; D019357:Potassium Citrate / Q000008:administration & dosage*; D012189:Retrospective Studies; D055815:Young Adult
D004232:Diuretics; D010710:Phosphates; D019357:Potassium Citrate