OVERVIEW
Pseudoaldosteronism is a rare salt-loss syndrome, also known as Cheek-Perry syndrome, first reported by Cheek and Perry (1958). Most cases develop in the neonatal period, and symptoms may appear in the first few hours of life, with recurrent vomiting, diarrhea, decreased or absent thirst, and growth retardation (or even idiocy) as the main symptoms; in some cases, the symptoms become apparent only after salt restriction or the application of aldosterone antagonists, and resolve spontaneously with age.
Etiology
The cause of the disease is a deficiency of aldosterone receptors in the patient’s target organs (renal tubules, salivary glands, sweat glands, and colon), or a reduced or complete failure of aldosterone to bind to its receptors; further studies in molecular biology and molecular biochemistry have revealed that pseudoaldosteronism is based on a genetically determined dysfunction of the sodium channels in the cell membranes.
Because a family history of salt loss can be traced in the majority of patients, the disease has been reported to be a hereditary disorder with either autosomal dominant or autosomal recessive inheritance.
Symptoms.
The target organ of the receptor is not always the same in different patients, and the degree of salt loss in its clinical manifestations varies in severity. In most cases, the disease develops in the neonatal period, and symptoms may appear in the first few hours of life, with recurrent vomiting, diarrhea, reduced or absent thirst, and growth retardation (or even idiocy) as the main symptoms; in some cases, the symptoms are revealed only after salt restriction or the application of aldosterone antagonists, and are relieved spontaneously as the patient grows older. Children with polyuria, hypotonic or isotonic dehydration, and severe electrolyte disorders due to high sodium in urine will die prematurely due to dehydration or secondary infections if effective treatment is not taken in a timely manner.
Pseudohypoaldosteronism is an autosomal disorder and is relatively rare. The renal tubules, salivary glands, and colonic mucosa are unresponsive to ALD in autosomal recessive inheritance, and the simple renal unresponsive type is dominant.
Examination
1. Biochemical changes are hyponatremia, hypochloremia and hyperkalemia, and some patients may have acidosis; hyperreninemia and high plasma aldosterone activity are also present. Urinary aldosterone excretion increases, but urine 17 ketone and 17 hydroxysteroid and ACTH test is normal.
2. Other auxiliary examinations: routine X-ray and ultrasound.
Diagnosis
According to the above clinical features, diagnosis is generally not difficult. The main points of diagnosis are:
1. Early age of onset, mostly in the neonatal period.
2. There are typical clinical manifestations, repeated vomiting, diarrhea, reduced or disappeared thirst, polyuria, hypotonic or isotonic dehydration, severe electrolyte disorders, some patients may have acidosis; children’s growth and intellectual development are backward.
3. No response to exogenous deoxycorticosterone acetate or 9α-fludrocortisone.
4. Plasma ALD, PRA, and ATII are elevated, but the renal tubules or salivary glands and colonic mucosa are resistant to hydrocortisone.
5. Laboratory tests are consistent with the disease. The disease can be diagnosed.
Differential diagnosis
This disease should be differentiated from the following diseases:
1. Salt loss syndrome
This disease should be differentiated from the salt-loss syndrome caused by 21-hydroxylase deficiency and 18-hydroxylase deficiency. Salt loss syndrome in addition to salt loss manifestations, at the same time there are abnormal development of external genitalia, that is, female masculinization or male pseudo-precocious puberty, plasma renin activity and aldosterone concentration tends to be lower than normal; blood ACTH is obviously elevated while plasma cortisol is obviously reduced, clinically effective treatment with cortisol. In addition to the clinical manifestation of salt loss, plasma renin activity is elevated while blood aldosterone concentration is reduced, and the application of exogenous aldosterone treatment is ineffective.
2. Renal salt-loss nephritis
This disease should also be distinguished from renal salt-losing nephritis. Renal salt-losing nephritis has a primary etiology and most often starts in adults. Patients may also present with hyponatremia and dehydration, but it is not a hereditary disease, so it can be distinguished from renal salt-losing nephritis.
3. Renal tubular acidosis
In addition to hyponatremia, renal tubular acidosis may also be characterized by hypocalcemia, hyperchloremia, hypokalemia, and so on, which can be differentiated from this disease.
Complications
Backward growth and development; electrolyte disorder and acidosis; secondary to various infectious diseases.
Treatment
In this disease, salt supplementation is the main treatment, and some children need sodium bicarbonate to correct acidosis. The indicators of effective treatment are the correction of salt loss, the recovery of thirst and the normalization of growth and development. In the vast majority of children, treatment can be stopped in about 2 weeks. Hyperkalemia can be corrected by sodium chloride supplementation (3-6 g/day), which lowers plasma renin and aldosterone levels and improves clinical symptoms.
Prognosis
The prognosis is generally good if detected and treated early.