Homozygosity or mixed heterozygosity for mutations in the adenine phosphoribosyltransferase gene cause enzyme deficiency directing adenine through an alternative metabolic pathway. This results in the production of 2,8-dihydroxyadenine, which is actively secreted into the urine. 2,8-dihydroxyadenine is insoluble at physiological urinary pH but as marked supersaturation is possible the manifestations differ: there may be minimal consequences, there may be infiltration of the tubulointerstitial tissue with acute or chronic damage or there may be stone formation in the urinary tract. Effective treatment can be offered and therefore the prognosis depends upon the renal function at diagnosis. Treatment consists of adequate fluid intake, a low-purine diet and administration of allopurinol. Urinary 2,8-dihydroxyadenine crystals are easily recognized under a microscope. The diagnosis of 2,8-dihydroxyadeninuria can be confirmed by estimation of adenine phosphoribosyltransferase activity in erythrocyte lysates. More than 300 cases of 2,8-dihydroxyadeninuria have been diagnosed worldwide, most of them in Japan, France and Iceland. One case has been reported in Finland but there have been no reports from the Scandinavian peninsula or from Denmark. The relevant mutations may be very rare in these countries but underdiagnosis is also possible.
The purpose of the study was to calculate the incidence of the acute flank pain syndrome in Iceland and to describe the case series.
The hospital records of those who fulfilled the following criteria were studied: age 18-41 years, acute renal failure, and a visit to Landspitali University Hospital in 1998-2007. The acute flank pain syndrome was defined as severe flank pain in combination with acute renal failure, unexplained except for the possible consumption of NSAIDs, ethanol or both. Information was collected about the sales of NSAIDs.
One hundred and six patients had acute renal failure. Of those, 21 had the acute flank pain syndrome (20%). The annual incidence of the acute flank pain syndrome increased threefold during the study period. The average incidence was 3.2/100.000/year (relative to the population of the Reykjavik area) and 2.0/100.000/year (relative to the population of Iceland). 18 patients were male and the median age was 26 (19-35) years. The symptoms regressed spontaneously during a few days or weeks. There was history of NSAID intake in 15, ethanol consumption in 15, either in 20, and both in nine patients. The sales figures of NSAIDs were high and they increased during the study period, especially those of the over-the-counter sales of ibuprofen.
The incidence of the acute flank pain syndrome was high. The paper describes the largest case series that has been published since the withdrawal of suprofen in 1987. Young people should be warned about consuming NSAIDs during or directly after binge drinking.
The incidence of encapsulating peritoneal sclerosis in patients on peritoneal dialysis seems to be increasing worldwide. In Iceland, two cases of encapsulating peritoneal sclerosis have recently been diagnosed (cumulative incidence 1.6%). The patients followed a similar course; the disease was diagnosed in the wake of a bacterial peritonitis, steroid treatment was effective during the acute phase but eventually surgical treatment was needed and a successful enterolysis performed.
Oral sodium phosphate solutions (OSPS) are widely used for bowel cleansing prior to colonoscopy and other procedures. Cases of renal failure due to acute phosphate nephropathy following OSPS ingestion have been documented in recent years, questioning the safety of OSPS. However, the magnitude of the problem remains unknown.
We conducted a population based, retrospective analysis of medical records and biopsies of all cases of acute phosphate nephropathy that were diagnosed in our country in the period from January 2005 to October 2008. Utilizing the complete official sales figures of OSPS, we calculated the incidence of acute phosphate nephropathy in our country. Fifteen cases of acute phosphate nephropathy were diagnosed per 17,651 sold doses of OSPS (0.085%). Nine (60%) were women and mean age 69 years (range 56-75 years). Thirteen patients had a history of hypertension (87%) all of whom were treated with either ACE-I or ARB and/or diuretics. One patient had underlying DM type I and an active colitis and one patient had no risk factor for the development of acute phosphate nephropathy. Average baseline creatinine was 81.7 µmol/L and 180.1 at the discovery of acute renal failure, mean 4.2 months after OSPS ingestion. No patient had a full recovery of renal function, and at the end of follow-up, 26.6 months after the OSPS ingestion, the average creatinine was 184.2 µmol/L. The average eGFR declined from 73.5 ml/min/1.73 m(2) at baseline to 37.3 ml/min/1.73 m(2) at the end of follow-up. One patient reached end-stage renal disease and one patient died with progressive renal failure.
Acute phosphate nephropathy developed in almost one out of thousand sold doses of OSPS. The consequences for kidney function were detrimental. This information can be used in other populations to estimate the impact of OSPS. Our data suggest that acute phosphate nephropathy may be greatly underreported worldwide.
Cites: Am J Kidney Dis. 2009 Mar;53(3):448-5619100671