The acute flank pain syndrome: a common presentation of acute renal failure in young males in Iceland

The acute flank pain syndrome: a common presentation of acute renal failure in young males in Iceland Sir, In 1987, the non-steroidal anti-inflammatory drug (NSAID) suprofen was withdrawn from the market due to ∼400 cases of the so-called 'acute flank pain syndrome' (AFPS) which was ascribed to the drug [1]. AFPS, characterized by severe flank pain, acute renal failure and recovery within 1 or 2 weeks, was most common in young males [2]. After withdrawal of suprofen, only a few reports have been published, associating AFPS with ingestion of other types of NSAIDS, binge drinking or both [3–5]. In Ice-land, the nephrologists have been aware of AFPS since the mid-1990s. By now, typical patients are managed with analgesics and by observation after minimal investigation. We screened the records of patients aged 18–41 years who received the diagnosis acute renal failure at Landspitali University Hospital during the period 1998–2007, and patients with AFPS were identified. AFPS was defined as severe flank or abdominal pain upon admission in combination with acute renal failure (serum creatinine concentration >50% increase of baseline or upper reference range), both features unexplained except for the possible intake of an NSAID, ethanol or both. Information about total and over-the-counter sales of ibuprofen and diclofenac during the study period was collected. There were 106 cases of acute renal failure. Of these, 21 (20%) had AFPS which amounts to an average incidence of 20.1/million/year. The incidence increased during the study period (Table 1). None of the AFPS patients had a history of kidney disease. Eighteen patients were males, and the median age was 26 (18–35)years. There was information about recent consumption of NSAIDs in 15 patients (ibuprofen in 8, diclofenac in 2, both in 2 and unknown type in 3), ethanol in 15 patients, either in 20 patients and both in 9 patients. The laboratory results are shown in Table 1. The sales figures of the NSAIDs were high, and they increased during the study period, especially the over-the-counter sales of ibuprofen (Table 2). This retrospective study underestimated the country-wide incidence of AFPS; an unknown number of patients who sought the advice of their general practitioners were never admitted to the hospital since the consultant neph-rologist recognized AFPS upon description. In spite of this, the study revealed the largest body of material of AFPS that has been reported since the suprofen experience. Moreover, the study showed that AFPS is a …