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Liddle Syndrome

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Topic updated on 11/04/17 7:40pm

Snapshot
  • A 3-year-old boy is brought to the pediatrician for a wellness visit. The mother reports that he has been sleeping and feeding well. She does not have any active concerns. Family history is significant for hypertension. His blood pressure is 110/90 mmHg. Laboratory testing is significant for hypokalemia and metabolic alkalosis.
Introduction
 

 
  • Clinical definition
    • a renal tubular disorder affecting the collecting tubules characterized by
      • hypertension
      • hypokalemia
      • metabolic alkalosis
    • also known as pseudohyperaldosteronism
  • Epidemiology
    • incidence
      • rare
    • demographics
      • young children
        • suspected if there is early onset hypertension
      • may not be detected until adulthood
    • risk factors
      • family history of early onset hypertension or hypokalemia may suggest Liddle’s
  • Pathogenesis
    • gain of function mutation involving the epithelial Na+ channel (ENaC) resulting in
      • increased Na+ reabsorption in the collecting tubules
      • this causes the lumen to be electronegative
        • which causes a gradient that favors secretion of K+ into the lumen
          • this results in decreased serum K+
      • mimics hyperaldosteronism
        • recall that aldosterone increases the number of open luminal Na+ channels
  • Genetics
    • inheritance pattern
      • autosomal dominant
    • mutations
      • chromosome 16p12
  • Prognosis
    • very good with treatment
Presentation
  • Symptoms
    • triad presenting at a young age
      • hypertension
      • hypokalemia
      • metabolic alkalosis
  • Physical exam
    • hypertension
Studies
  • Labs
    • hypokalemia
    • metabolic alkalosis
    • ↓ aldosterone
    • ↓ renin
    • genetic testing
      • most definitive diagnosis
Differential
  • Primary hyperaldosteronism
  • Congenital adrenal hyperplasia
 
Renal Tubular Defects
Category
Fanconi Syndrome
Bartter Syndrome Gitelman Syndrome Liddle Syndrome
Defect localization
  • Proximal tubule
  • Thick ascending loop of Henle
  • Distal convoluted tubule
  • Collecting tubule
Etiology
  • Wilson disease
  • Tyrosinemia
  • Cystinosis
  • Multiple myeloma
  • Galactosemia
  • Mitochondrial myopathies
  • Medications
    • aminoglycosides
    • cisplatin
    • ifosfamide
    • valproic acid
  • Heavy metals
    • mercury 
    • lead
  • Autosomal recessive mutation involving the NKCC2 cotransporter
  • Autosomal recessive mutation involving the NaCl cotransporter
  • Autosomal dominant mutation leading to increased activity of ENaC
Findings
  • Hypophosphatemia
  • Aminoaciduria
  • Renal glucosuria
  • Tubular proteinuria
  • Proximal renal tubular acidosis
  • Hypokalemia
  • Hypochloremia
  • Metabolic alkalosis
  • Normotension
  • Elevated plasma renin level
  • Hypokalemia
  • Hypochloremia
  • Metabolic alkalosis
  • Hypomagnesemia
  • Hypocalciuria
  • Normotension
  • Hypertension
  • Hypokalemia
  • Metabolic alkalosis
 
Treatment
  • Medical
    • potassium-sparing diuretics
      • indication
        • for all patients with Liddle syndrome
        • recall that these medications directly block Na+ channels in the collecting tubules
      • drugs
        • amiloride
        • triamterene
Complications
  • Cardiac arrhythmia due to hypokalemia  


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