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Liddle syndrome is a rare hereditary disorder in which the kidneys excrete K but retain too much Na and water, leading to hypertension. Symptoms are of hypertension, fluid retention, and metabolic alkalosis. Diagnosis is through measurement of urinary electrolytes. K-sparing diuretics provide the best treatment.

Liddle syndrome is a rare autosomal dominant disorder of renal epithelial transport that clinically resembles primary aldosteronism (see Adrenal Disorders: Primary Aldosteronism), with hypertension and hypokalemic metabolic alkalosis but without elevated plasma renin or aldosterone levels. The syndrome results from an inherently increased activity of the luminal membrane Na channels, which accelerates Na resorption and K secretion in the collecting tubule.

Patients with Liddle syndrome present at < 35 yr. Hypertension and signs and symptoms of hypokalemia (see Fluid and Electrolyte Metabolism: Hypokalemia) and metabolic alkalosis occur.

Diagnosis

• Urine Na level
• Plasma renin and aldosterone levels

Diagnosis is suggested by the presence of hypertension in a young patient, particularly one with a positive family history. Low urine Na (< 20 mEq), normal plasma renin and aldosterone levels, and response to empiric treatment usually are considered sufficient to confirm the diagnosis. Definitive diagnosis can be achieved through genetic testing (see www.genetests.org for more information).

Treatment

Triamterene Some Trade Names
DYRENIUM
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(100 to 200 mg po bid) or amiloride Some Trade Names
MIDAMOR
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(5 to 20 mg po once/day) are effective because they close Na channels. Spironolactone Some Trade Names
ALDACTONE
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is ineffective.

Last full review/revision September 2009 by Peter C. Brazy, MD

Content last modified September 2009