Calculi urinary, uric acid

On the other hand, the amorphous urate accumulations within the tubules are clearly dependent upon the concentration of uric acid in tubular urine. This is dependent upon both the total urate excretion, the urine volume and also the urine pH. Now both of these types of deposit are well recognized as occurring in gouty kidneys (2), as is the fact that their presence predisposes to hypertension, arterial disease, renal calculus formation, urinary tract infection and moderate degrees of renal insufficiency (3). 

A previously unknown concrete acid calculus) was separated by Scheele from urinary calculi (uric acid) and shown to be present in small quantities in urine. The red colour (murexide) formed on evaporating it with nitric acid was observed. By heating uric acid he obtained a sublimate (afterwards called pyrouric acid) which he thought was similar to succinic acid it is really cyanuric acid. ... 

Marcet discovered in a urinary calculus a substance which he called xanthic oxide, since it was soluble in alkalis and on evaporation with nitric acid gave a yellow substance. Its correct formula, C5H4O2N4, was first found by Wohler and Liebig, and since it contains one atom of oxygen less than uric acid, Berzelius called it urous acid (Harnige Saure). It is now called xanthine it can be obtained by reducing uric acid with sodium amalgam and is colourless when pure. ... 

A tentative diagnosis of a right renal uric acid calculus was made. The patient was placed on intravenous fluids and parenteral analgesics. A CAT scan was performed, which showed a translucent calculus present in the lower right ureter close to its insertion into the urinary bladder. A serum uric acid was completed and was reported as above normal. His urine was continually monitored to note total output as well as to attempt to obtain the stone should it be passed. 

This patient presented with a very typical history and symptom complex for a uric acid calculus. This is a condition that usually occurs in males, and there usually is a familial history. In addition, his diet contributed to the condition. He was in some ways very fortunate that the urinary problem developed at an early stage in his development of gout. His maintenance of a proper diet and medication should prevent him from pathological changes developing that would have occurred in his joints, because the condition was diagnosed before the onset of bony changes with joint destruction. 

Based on the United States Renal Data System, which reported their retrospective records of 42,096 renal transplant recipients between 1994 and 1998, the incidence of urolithiasis was 0.11% for males and 0.15% for females (Abbott et al. 2003). At the time of calculus discovery, 67% had kidney stones and 33% ureteral stones. Uric acid stones are much less common than calcium calculi. The stones can be transplanted from cadaveric or living donors or develop de novo, favored either by metabolic disorders (tertiary hyperparathyroidism, hypercalciuria, hypocitraturia) or infection (Proteus tnirabilis), or the presence of a foreign body in the urinary tract (double-J stent) (Crook and Keoghane 2005). 

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