Overview of Pseudo-hyperaldosteronism
Pseudo-hyperaldosteronism (PHA), also known as Liddle syndrome, renal sodium retention syndrome, congenital renal tubular hyperkalemia, hypo-reninotropic hypertension syndrome, and pseudo-hyperaldosteronism, is a renal tubular disease characterized by severe hypertension, hypokalemia, metabolic alkalosis, and hypo-reninotropic hyponatremia without hyperaldosteronism. Renal tubular disease, which is hereditary and inherited in an autosomal dominant manner. The disease has no possibility of self-healing and requires active and correct treatment of hypertension and chronic hypokalemia to prevent complications.
Etiology
Autosomal dominant, caused by mutations in the gene for the aminoclopramide-sensitive epithelial sodium channel (eNaC), which determines Na+ reabsorption in distal renal units.
Symptoms
Typical clinical manifestations are hypertension, hypokalemia, and metabolic alkalosis. The clinical phenotype varies widely by gene exonucleosis and environmental influences.
1. Hypertension
Hypertension is the earliest and most common symptom, which occurs more frequently in adolescents and is more serious.
2. Hypokalemia
Such as muscle weakness, periodic paralysis, hand and foot twitching, and even rhabdomyolysis (with elevated plasma creatine phosphokinase), sensory abnormalities, polyuria, and irritable thirst.
Examination
1. Blood potassium
Generally as low as 2.4～2.8mmol/L, sometimes only mildly low potassium, 3.0～3.6mmol/L, very low potassium (1.8～2.2mmol/L) is rare.
2. Metabolic alkalosis
Plasma HCO3- levels are elevated, and arterial blood pH is elevated. Blood sodium increases, plasma renin and aldosterone levels are low. Decreased urinary sodium, increased urinary potassium, low urinary aldosterone levels.
Diagnosis.
Diagnosis is made on the basis of history, clinical manifestations, and laboratory tests; ultrasound, CT, and MRI of the adrenal glands are helpful.
Treatment
Pseudoaldosteronism is sensitive to salt restriction and sodium channel blockers (potassium-preserving diuretics). Potassium-preserving diuretics amphotericin and amiloride have good efficacy, which can directly inhibit the luminal membranes of distal convoluted tubules and collecting ducts, ENaC, and inhibit Na+ reabsorption, so that urinary sodium is increased and urinary potassium is decreased. Strict salt restriction or moderate salt restriction plus potassium-preserving diuretics can normalize blood pressure and restore plasma renin and aldosterone levels.
Thiazide diuretics are also effective in treating pseudoaldosteronism, but require large potassium chloride supplementation; alternatively, sodium intake can be restricted and thiazide diuretics, aminopterin, or amiloride can be administered.
Frequent monitoring of blood pressure and potassium is required during treatment, and the regimen is adjusted accordingly; if blood pressure is elevated, the diuretic dosage is increased or sodium intake is further restricted. If blood potassium levels are low, potassium chloride is to be supplemented and the dosage of aminopterin or amiloride is to be increased. Potassium chloride and not potassium bicarbonate should be used, as the disease itself is alkalized and alkaline potassium salts should not be used.
The hydrocorticoid receptor antagonist spironolactone is ineffective against plasma renin and aldosterone due to their low levels and can lead to hyponatremia with prolonged application.