Tubular Disorders

Question 1

What characteristic does Liddle syndrome, bartter and Gitelman syndrome all have in common?

Answer 1

• They are hereditary
• Hypokalaemia and metabolic alkalosis
• Barrter/Gitelman: hypokalaemia without HTN, autosomal dominant condition affecting sodium chloride reabsorption
• Liddle: hypokalaemia with HTN

Barrter
- Defective Na/K/Cl cotransport in ascending loop of henle
- Hypokalaemia, hyponatremia, hyperCALCIURIA
- Hypotension/normal
- High aldosterone/renin
- Tx: electrolyte replacement + NSAIDs
potassium-sparing diuretics (spironolactone, amiloride)

Gitelman
- Defective Na/CL cotransporter in distal convoluted tubules
- Hypokalaemia, hypomagnesemia, hypoCALCIURIA
- Hypotension/normal
- High aldosterone/renin
- Tx: electrolyte replacement + NSAIDs
potassium-sparing diuretics (spironolactone, amiloride)

Liddle:
- defective epithelial sodium channel in the collecting duct
- HTN
- Low renin/aldosterone
- Hypokalaemia/metabolic alkalosis + HYPERTENSION
- Tx:Lifelong oral potassium substitution with potassium-sparing diuretics that directly block ENaCs in the collecting duct (e.g., amiloride, triamterene)
Spirnolactone does not work due to low aldosterone levels