Metabolic Acidosis, Hyperkalemia, and Renal Unresponsiveness to Aldosterone Syndrome: Response to Treatment with Low-Potassium Diet.

Gordon syndrome involves hyperkalemia, acidosis, and severe hypertension (HTN) with hypercalciuria, low renin and aldosterone levels. It is commonly observed in children and adolescents. Such patients respond successfully to sodium restriction and thiazide diuretics. In this article, we present three cases of metabolic acidosis, hyperkalemia, and renal unresponsiveness to aldosterone (MeHandRU Syndrome). All three patients did not have HTN or hypercalciuria and demonstrated normal renin and aldosterone levels. These patients did not respond to thiazide-type diuretic therapy and salt restriction. Two males (aged 55- and 62-year) and a female patient (aged 68-year) presented to the clinic with unexplained hyperkalemia (5.9 mEq/L, 5.9 mEq/L and 6.2 mEq/L, respectively). On physical examination, blood pressure (BP) was found to be normal (<140/90 mm Hg). Over the counter potassium supplement, nonsteroidal anti-inflammatory drugs, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, potassium sparing diuretic use, as well as hyporeninemic hypoaldosteronism states such as diabetes mellitus were excluded. Plasma renin and aldosterone levels were normal. All three patients had low transtubular potassium gradient, despite high serum potassium levels. None of the patients reported a family history of hyperkalemia or kidney failure. All failed to demonstrate a response to hydrochlorothiazide and salt restriction. After careful consideration, strict low potassium diet (<2 g/day) was initiated in consultation with the dietician. Diuretic therapy was discontinued while BP remained within normal range (<140/90 mm Hg). At eight weeks, all three patients demonstrated normalization of potassium and correction of acidosis. At follow-up of six months, all patients are maintaining a normal potassium level. We suggest that potassium restriction can be successful in patients presenting with MeHandRU syndrome.

Structural chromosome disruption of the NR3C2 gene causing pseudohypoaldosteronism type 1 presenting in infancy.

Type I pseudohypoaldosteronism (PHA1) is a rare form of mineralocorticoid resistance presenting in infancy with renal salt wasting and failure to thrive. Here, we present the case of a 6-week-old baby girl who presented with mild hyponatraemia and dehydration with a background of severe failure to thrive. At presentation, urinary sodium was not measurably increased, but plasma aldosterone and renin were increased, and continued to rise during the subsequent week. Despite high calorie feeds the infant weight gain and hyponatraemia did not improve until salt supplements were commenced. Subsequently, the karyotype was reported as 46,XX,inv (4)(q31.2q35). A search of the OMIM database for related genes at or near the inversion breakpoints, showed that the mineralocorticoid receptor gene (NR3C2) at 4q31.23 was a likely candidate. Further FISH analysis showed findings consistent with disruption of the NR3C2 gene by the proximal breakpoint (4q31.23) of the inversion. There was no evidence of deletion or duplication at or near the breakpoint. This is the first report of a structural chromosome disruption of the NR3C2 gene giving rise to the classical clinical manifestations of pseudohypoaldosteronism type 1 in an infant.

[Type Ib pseudohypoaldosteronism: clinical aspects and nosological problems. Apropos of 3 cases]. / Pseudo-hypoaldostéronisme de type Ib: particularités cliniques et problèmes nosologiques. A propos de trois cas.

BACKGROUND: Type Ib pseudohypoaldosteronism is a congenital disorder characterized in the newborn by salt loss caused by multiple end-organ resistance to aldosterone. An autosomal recessive mode of inheritance has been reported. Its particularity is the spontaneous improvement by 18 months to 2 years, due to an improved tubular response of the kidneys to mineralocorticoids, or earlier when given salt supplements once the diagnosis is made. OBSERVATIONS: We observed three children with this disease, which was revealed by day 8 to day 15 of life; one of these presented respiratory symptoms identical to those of cystic fibrosis, and another one an apparently chance association with a rod myopathy. CONCLUSION: Recent findings in the literature demonstrate the molecular aspects of pseudohypoaldosteronism and lead to an interesting comparison with cystic fibrosis by explaining their similar physiopathology through the activity of epithelial sodium channels.

Long term observations in a patient with pseudohypoaldosteronism.

This paper describes a patient with severe pseudohypoaldosteronism (PHA) for over 12 years. The patient presented at 10 days of age with a serum sodium of 118 mEq/l and potassium of 12 mEq/l. After failing to maintain normal fluid and electrolyte status with standard therapy, including maximal mineralocorticoid stimulation, he was given a special formula containing minimal potassium plus salt supplements which normalized his electrolyte status. However, when he was 4.5 years of age, an acute gastrointestinal illness led to severe volume depletion, hyperkalemia, and cardiopulmonary arrest. This resulted in significant neurological impairment. At 12.5 years of age, the patient continues to require massive sodium supplements and his diet contains less than 0.5 mEq/kg potassium daily; his height and weight are at the 95th percentile, thus demonstrating that normal growth may be achieved with strict dietary manipulation in a patient with persistent, severe PHA. Serial studies to further define the lesion in this patient have demonstrated: (1) normal binding of aldosterone to aldosterone binding globulin (5.1% bound); (2) normal mineralocorticoid "activity"; (2) suppressible renin and aldosterone levels; (4) increased prostaglandin excretion (3.15 micrograms/g creatinine); (5) lack of benefit of prostaglandin inhibition with indomethacin; (6) normal proximal tubule function (CNa + CH2O = 18.0 ml/100 ml glomerular filtration rate; (7) impaired distal tubule function (CH2O/CNa + CH2O = 79.8%) during water diuresis.