Transient pseudo-hypoaldosteronism following resection of the ileum: normal level of lymphocytic aldosterone receptors outside the acute phase

Pseudo-hypoaldosteronism (PHA) is due to mineralocorticoid resistance and m anifests as hyponatremia and hyperkalemia with increased plasma aldosterone levels. It may be familial or secondary to abnormal renal sodium handling. We report the case of a 54-year-old woman with multifocal cancer of the co lon, who developed PHA after subtotal colectomy, ileal resection and jejuno stomy. She was treated with 6 g of salt daily to prevent dehydration, which she stopped herself because of reduced fecal tosses. One month later she w as admitted with signs of acute adrenal failure, i.e. fatigue, severe nause a, blood pressure of 80/60 mmHg, extracellular dehydration, hyponatremia (1 18 mmol/l); hyperkalemia (7.6 mmol/l), increased blood urea nitrogen (BUN) (200 mg/dl) and creatininemia (2.5 mg/dl), and decreased plasma bicarbonate s level (HC03(-): 16 mmol/l; N: 27-30). However, the plasma cortisol was hi gh (66 mu g/100 mi at 10:00 h; N: 8-15) and the ACTH was normal (13 pg/ml, N: 10-60); there was a marked increase in plasma renin activity (>37 ng/ml/ h; N supine <3), active renin (869 pg/ml; N supine: 1.1-20), aldosterone (> 2000 pg/ml; N supine <150) and plasma AVP (20 pmol/l; N: 0.5-2.5). The plas ma ANH level was 38 pmol/l (N supine: 5-25). A urinary steroidogram resulte d in highly elevated tetrahydrocortisol (THF: 13.3 mg/24h; N: 1.4+/-0.8) wi th no increase in tetrahydrocortisone (THE: 3.16 mg/24h; N: 2.7+/-2.0) excr etion, and with low THE/THF (0.24; N: 1.87+/-0.36) and alpha THF/THF (0.35; N: 0.92+/-0.42) ratios. The number of mineralocorticoid receptors in monon uclear leukocytes was in the lower normal range for age, while the number o f glucocorticoid receptors was reduced. Small-bowel resection in ileostomiz ed patients causes excessive fecal sodium losses and results in chronic sod ium depletion with contraction of the plasma volume and severe secondary hy peraldosteronism. Nevertheless, this hyperaldosteronism may be associated w ith hyponatremia and hyperkalemia suggesting PHA related to the major impor tance of the colon for the absorption of sodium. In conclusion, this case r eport emphasizes I)the possibility of a syndrome of acquired PHA with sever e hyperkalemia after resection of the ileum and colon responding to oral sa lt supplementation; 2) the major increase in AVP and the small increase in ANH; 3) the strong increase in urinary THF with low THE/THF and alpha THF/T HF ratios; 4) the normal number of lymphocytic mineralocorticoid receptors outside the acute episode. (C) 1999, Editrice Kurtis.