Makindo Medical Notes

Bartter's syndrome 🧬 is a rare inherited renal tubular disorder that causes defective electrolyte handling. It is marked by hypokalaemia ⚡, metabolic alkalosis, and high renin/aldosterone — but without hypertension 🚫🩸, which is the key differentiator from other causes of secondary hyperaldosteronism.

About 📖

• Characterized by low potassium (hypokalaemia) ⚡.
• Blood pressure is normal or low 🩸⬇️.
• Pathophysiology resembles the chronic use of loop diuretics (Furosemide 💊).

Aetiology 🔬

• Genetic defect in tubular ion transport proteins.
• Most commonly affects the Na-K-2Cl co-transporter in the thick ascending limb of the loop of Henle.
• Consequences include:
• ↑ Urinary loss of K⁺ and H⁺ → hypokalaemia ⚡ + metabolic alkalosis 🧪.
• ↑ Prostaglandin production 🌀 contributing to salt wasting.
• Juxtaglomerular hyperplasia → ↑ renin & aldosterone 🔄.

Clinical Features 👶👦

• Infants: poor feeding, tiredness & lethargy 💤 due to K⁺ loss.
• Failure to thrive 🚼 common in children.
• Muscle weakness, cramps, constipation 💪⚡.
• Normal/low BP (distinguishes from hyperaldosteronism) 🩸⬇️.
• Can present as growth failure in childhood/adolescence 📉.

Investigations 🧪

• ↑ Renin & Aldosterone (secondary hyperaldosteronism).
• Hypokalaemic metabolic alkalosis ⚡🧪.
• Hypercalciuria 💧 (excess urinary calcium), may lead to nephrocalcinosis.
• Defective Na/K/Cl co-transporter confirmed genetically.
• Normal/low BP despite RAAS activation 🚫🩸.

Differential Diagnosis 🔍

• Chronic vomiting 🤮 or diarrhoea 💩.
• Diuretic abuse 💊.
• Magnesium deficiency 🧂.
• Gitelman syndrome (similar but with hypomagnesaemia and no hypercalciuria).

Management 💊

• Electrolyte supplementation: Oral Na⁺ & K⁺ to correct losses.
• Potassium-sparing diuretics: Spironolactone or Amiloride ⚡ to reduce K⁺ wasting.
• NSAIDs (e.g. Indomethacin): Reduce prostaglandin production 🌀.
• ACE inhibitors/ARBs: May be used to blunt RAAS overactivity.

Key Clinical Pearl ✨

• Bartter’s = hypokalaemia + metabolic alkalosis + high renin/aldosterone + normal/low BP 🧪⚡🩸⬇️.
• Think of it as the “genetic Furosemide effect” 💊.