title: Unilateral adrenal hyperplasia is a usual cause of primary hyperaldosteronism. Results from a Swedish screening study.
abstract: BACKGROUND
  The existence of unilateral adrenal hyperplasia (AH) has been considered a rare cause of primary hyperaldosteronism (PA).
  
  
  METHODS
  In a prospective study we screened for PA in a non-selected (NSP) and selected hypertensive population (SP), to define the cause of PA. We included 353 consecutive patients with hypertension; age 20 to 88 years, 165 women and 188 men, from a university-based Hypertension and Nephrology Outpatient clinics (123 SP) and two primary care centres, (230 NSP) from the same catch-up area. Serum aldosterone and plasma renin activity (PRA) were measured and the ARR calculated. Verifying diagnostic procedure was performed in patients with both elevated aldosterone and ARR. Patients diagnosed with PA were invited for adrenal venous sampling (AVS) and offered laparoscopic adrenalectomy when AVS found the disease to be unilateral.
  
  
  RESULTS
  After screening, 46 patients, 13% of the whole population (22.8% SP and 7.8% NSP) had aldosterone and ARR above the locally defined cut-off limits (0.43 nmol/l and 1.28 respectively). After diagnostic verification, 20 patients (6%) had PA, (14.5% SP and 1.4% NSP). Imaging diagnostic procedures with CT-scans and scintigraphy were inconclusive. AVS, performed in 15 patients verified bilateral disease in 4 and unilateral in 10 patients. One AVS failed. After laparoscopic adrenalectomy, 4 patients were found to have adenoma and 5 unilateral AH. One patient denied operation.
  
  
  CONCLUSIONS
  The prevalence of PA was in agreement with previous studies. The study finds unilateral PA common and unilateral AH as half of those cases. As may be suspected PA is found in much higher frequency in specialised hypertensive units compared to primary care centers. AVS was mandatory in diagnosis of unilateral PA.
authors.affiliation: Department of Medicine, Centrum of Endocrinology and Metabolism, Sahlgrenska University Hospital, University of Gothenburg, Gothenburg, Sweden. helga.sigurjonsdottir@medic.gu.se.
authors.forename: Helga Agusta
authors.initials: HA
authors.lastname: Sigurjonsdottir
authors.forename: Mikael
authors.initials: M
authors.lastname: Gronowitz
authors.forename: Ove
authors.initials: O
authors.lastname: Andersson
authors.forename: Robert
authors.initials: R
authors.lastname: Eggertsen
authors.forename: Hans
authors.initials: H
authors.lastname: Herlitz
authors.forename: Augustinas
authors.initials: A
authors.lastname: Sakinis
authors.forename: Bo
authors.initials: B
authors.lastname: Wangberg
authors.forename: Gudmundur
authors.initials: G
authors.lastname: Johannsson