Renal symptomatology in patients with acute intermittent porphyria. A population-based study

Objective. Can renal insufficiency in subjects with acute intermittent porp hyria (AIP) be due solely to AIP? Design. A population-based study. Subjects. Subjects with AIP greater than or equal to 18 years of age (n = 3 86) in the four most northerly counties of Sweden. Interventions. Screening with creatinine clearance at 24 h. Patients below the lower reference level underwent a repeat clearance test and, if still l ow, also chromEDTA clearance. Results. 286 (74%) subjects performed the creatinine clearance test and in 57 clearance was low; the second clearance proved normal in 23 who were the n excluded. Eighteen subjects with other possible medical reasons for renal insufficiency, ethical reasons or refusing further examinations were also excluded. The 16 remaining subjects with no explanation for their renal ins ufficiency other than AIP were then studied in detail. All 14 women, mean a ge 52 years, and two uraemic men, 58 and 67 years, had manifest AIP. Twelve patients had hypertension (HT) and four were normotensive in spite of rena l insufficiency. Histological findings of renal biopsies revealed diffuse g lomerulosclerotic and interstitial changes with additional ischaemic lesion s. Conclusion. Protracted vasospasm in attacks of AIP may be a cause of renal lesions. This is discussed.