Primary aldosteronism: Review

• Src: http://www3.interscience.wiley.com/cgi-bin/fulltext/117998266/PDFSTART;

Subtypes of primary aldosteronism

• Aldo.-producing adenoma (APA): 35% of cases
• Bilat. idiop. hyperplasia (IHA): 60% of cases
• Prim. (unilat.) adrenal hyperplasia: 2%
• Pure aldo.-producing adrenocortical carcinoma: <1%
• Familial hyperaldosteronism (FH)
• Glucocorticoid-remediable aldosteronism (FH type 1): <1%
• FH type 2 (APA or IHA): ?%
• Ectopic aldo.-producing adenoma or carcinoma: <0.1%

Investigations

• When to consider testing for Primary Aldosteronism:
• Htn and hypokalaemia
• resistant htn
• adrenal incidentaloma and htn
• onset of htn at a young age (<20 y)
• severe htn (>=160/100)
• whenever considering secondary htn
• Test morning blood sample in seated ambulant patient
  
• Plasma aldo. concentration (PAC)
• Plasma renin activity (PRA or PRC)
• Results: investigate for prim. aldosteronism if:
  
• icrd PAC (>416pmol/l; >15ng/dl)
• AND: dcrd PRA (<1.0ng/ml/h) OR dcrd PRC (<LL of detection for assay)
• AND: icrd PAC/PRA ratio >=555(pmol/l)/(ng/ml/h) (>=20(ng/dl)/(ng/ml/h))