Liddle Syndrome

At a Glance

The clinical presentation is that of polyuria and polydipsia, failure to thrive, and systemic hypertension in infancy and/or early childhood. This is an autosomal dominant form of inheritance, so a family history of the same is supportive.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

The clinical findings of hypertension and aboratory findings reveal a hypokalemic metabolic alkalosis, and evidence of depressed levels of renal and aldosterone should alert the clinician to Liddle syndrome as a cause. Renal function and renal imaging are normal in these children.(Table 1)

Table 1

Test Results Indicative of the Disorder

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?

The laboratory findings of a hypokalemic metabolic alkalosis may occur from diuretic use (abuse), but diuretic use will not result in hypertension, nor low aldosterone or renin levels.

What Lab Results Are Absolutely Confirmatory?

The following are absolutely confirmatory:

• family history

• hypertension, failure to thrive

• hypokalemic metabolic alkalosis

• hypo renin and hypo aldosterone

• genetic testing

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

This syndrome is associated with mineralocorticod excess that does not respond to Spironolactone. The clinical improvement of the hypertension after the initiation of amiloride and triamterene is pathognomonic of this syndrome. Potassium supplement or a high potassium diet is also usually needed.