OVERVIEW
Gordon syndrome is hyperkalemic, hyperchloremic, and hyporeninemic hypertension, also known as familial hyperkalemic hypertension or type II pseudoaldosteronism, a rare autosomal dominant disorder. There is no effective method of prevention, and the prognosis depends on the blood pressure level. Sodium-restricted diets and thiazide diuretics are very effective in treating Gordon’s syndrome.
Etiology
Due to congenital renal tubular defects, renal sodium reabsorption is increased, resulting in elevated sodium and chloride, leading to blood volume expansion and hypertension; renin secretion is inhibited, so plasma renin activity is reduced. Due to the decrease of renal potassium excretion, hyperkalemia is produced. Acidosis is mainly caused by hyperkalemia.
Symptoms
The biochemical disturbances of Gordon’s syndrome begin at birth, whereas hypertension most often occurs in adulthood. Hyperkalemia and hyperchloremic acidosis with low plasma renin activity and normal glomerular filtration rate, with or without hypertension, should be considered Gordon syndrome.
Complications of Gordon’s syndrome are similar to those of hypertension and can be complicated by stroke, left ventricular failure, hypertensive retinopathy, and hypertensive nephropathy. Patients tend to tolerate chronic hyperkalemia. In severe cases of hyperkalemia, there may be muscle weakness or paralysis.
Examination
1. Hyperkalemia is essential for the diagnosis of the disease, and multiple blood potassium checks are advisable.
2. Hyperchloremic acidosis, with a decrease in plasma carbonate concentration and a decrease in arterial blood pH in most cases.
3. Plasma renin activity is significantly reduced, and plasma aldosterone levels are mostly normal. However, aldosterone levels are low for hyperkalemia compared to the norm at normokalemia. Atrial natriuretic peptide is normal or mildly elevated.
4. Blood creatinine and urea nitrogen reflecting renal function, endogenous creatinine clearance is often in the normal range, and urine concentrating function is normal.
Diagnosis
Chronic hyperkalemia should be considered when other symptoms are often not apparent. In the diagnosis and treatment of hypertension, it is important to be alert to the presence of this disease, and when suspicious signs are found, further examination should be carried out with a view to early detection and early treatment. The diagnosis of the disease can be made on the basis of clinical manifestations and laboratory tests.
Differential diagnosis
The glomerular filtration rate is normal in Gordon’s syndrome. In contrast, all other diseases can have a temporary or persistent decrease in glomerular filtration rate. Isolated hypoaldosteronism, Addison’s disease, and pseudohypoaldosteronism all have aldosterone deficiency or resistance, resulting in renal sodium loss and decreased blood volume, which elevates plasma renin along with decreased glomerular filtration rate.
Treatment
Thiazide diuretics are very effective in the treatment of Gordon’s syndrome. They can reduce blood pressure to normal levels, and hyperkalemia, hyperchloremia, and acidosis can be corrected. Prolonged use may produce hypokalemia, hypochloremic alkalosis, hyperuricemia, hyperglycemia, and hypercalcemia. It is advocated to start with a small dose and adjust the therapeutic dose of diuretics according to changes in blood pressure and changes in blood potassium and blood chloride.
Sodium-restricted diet also achieves good therapeutic effect and can improve hyperkalemia and hyperchloremia.
Prognosis
There is no effective method of prevention. The prognosis depends on the blood pressure level. Treated patients who respond well to thiazide diuretics have fewer complications than patients with normal hypertension.