Foscarnet-induced crystalline glomerulonephritis with nephrotic syndrome and acute renal failure after kidney transplantation.

Foscarnet nephrotoxicity has been reported to be associated with acute tubulointerstitial nephritis. Crystals in glomerular capillary lumens have also been observed in patients with acquired immunodeficiency syndrome who were treated with foscarnet for cytomegalovirus disease. We describe a kidney transplant recipient who developed a nephrotic syndrome with microscopic hematuria and nonoliguric acute renal failure within 15 days after starting foscarnet therapy for cytomegalovirus infection. A kidney biopsy specimen showed the presence of crystals in all glomeruli and in proximal tubules. Fourier transform infrared microscopy analysis demonstrated that crystals were made from several forms of foscarnet salts: mixed calcium and sodium salts, and unchanged trisodium foscarnet salts. Renal function and proteinuria spontaneously improved, and a second transplant biopsy performed 8 months after the first one revealed fibrotic organization of half of the glomeruli and of interstitial tissue, and crystal vanishing. We were thus able to provide proof of the possible precipitation of foscarnet in a transplanted kidney.

Identification of crystals in kidneys of AIDS patients treated with foscarnet.

Three acquired immune deficiency syndrome patients given foscarnet to treat cytomegalovirus retinitis developed renal failure with crystal deposits within the renal glomeruli. We identified these crystals as a mixture of sodium salt, calcium salt, and a mixed salt containing both sodium and calcium ions. This composition has not been previously reported. Foscarnet can complex available ionized calcium and secondarily precipitate in glomeruli. The percentage of complexing depends on calcium concentration in serum and the poor calcium salt solubility.

Advantage of zero-crossing-point first-derivative spectrophotometry for the quantification of calcium oxalate crystalline phases by infrared spectrophotometry.

The main component of urinary calculi in industrialized countries is calcium oxalate. Its detection in stones is easily performed by infrared spectrophotometry. However its two crystalline forms calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD), which are linked to different aetiologies, provide similar patterns, with overlapping vibrations leading to difficulties in differentiation and quantitation of both the phases in mixtures. Some minor but characteristic bands of each crystalline species are emphasized for analytical purposes. The method of zero-crossing-point first-derivative spectrophotometry was applied to calcium oxalate species quantitation and revealed to be easy, accurate, precise and very well adapted to routine laboratories.

Crystalline phase differentiation in urinary calcium phosphate and magnesium phosphate calculi.

UNLABELLED: Phosphates are encountered as the main components in about 15% of urinary calculi. Except for struvite, no specific correlations have been found between the crystalline phase of the phosphates and the cause of nephrolithiasis. OBJECTIVE: The relationship between aetiological factors and crystalline phases or carbonate rate in calcium phosphate stones were assessed. MATERIAL AND METHODS: From a series of 1148 phosphate calculi, we investigated the relationship between composition and aetiological factors. RESULTS: Carbapatite was the most frequent crystalline phase (74.0%). It was associated with many possible causes, including hypercalciuria, hypocitraturia, primary hyperparathyroidism, tubular acidosis, medullary sponge kidney and chronic urinary tract infection. The carbonate rate of carbapatite may be of clinical interest because carbonate rates above 15% are frequently related to urinary tract infection with urea-splitting bacteria. Conversely, the carbonate rate was commonly less than 10% in cases of carbapatite induced by metabolic disorders. Among other phosphates, brushite was found in hypercalciuric states and primary hyperparathyroidism and whitlockite in cases of urinary tract infection by non-urease-producing bacteria. CONCLUSION: Identification of crystalline phases and measurement of carbonate rate in calcium phosphate calculi is of clinical interest for identifying stone aetiology.

Irreversible glomerular lesions induced by crystal precipitation in a renal transplant after foscarnet therapy for cytomegalovirus infection.

AIMS: Foscarnet is an antiviral agent used to treat cytomegalovirus infection in AIDS patients and in transplant recipients. In most cases, foscarnet induces reversible tubulo-interstitial lesions which can be avoided by correct hydration. We report the first case of crystal foscarnet precipitation within glomerular capillaries in a renal transplant. METHODS AND RESULTS: The recipient, a 49-year-old man, developed a nephrotic syndrome with haematuria and an acute renal failure after foscarnet therapy for cytomegalovirus (CMV) infection. The polarization examination of the first graft biopsy revealed the presence of birefringent crystals within glomeruli and tubules. Infrared analysis attested to the presence of trisodium foscarnet salts and mixed sodium calcium salts coloured by Von Kossa's reaction. A second biopsy showed glomerular sclerosis, interstitial fibrosis, tubular atrophy and crystal vanishing. Polymerase chain reaction (PCR) in situ applied to this biopsy confirmed the diagnosis of cytomegalovirus infection. CONCLUSIONS: These adverse effects might be the result of a toxic synergy between foscarnet and other drugs. In cases with crystalline precipitation, graft biopsy remains the best mean of diagnosis and follow-up of glomerular damage.