Bartter syndrome natural history, complications and prognosis

Bartter Syndrome usually occurs in childhood. Bartter syndrome type I and type II are salt-wasting renal tubular disorders that are clinically characterized by polyhydramnios leading to premature delivery, marked polyuria, and a tendency towards nephrocalcinosis. Common complications of Bartter syndrome include Gallstones, Rhabdomyolysis, Prolonged QT interval, Life-threatening arrhythmia, Syncope, Sudden death, weakening of the bones and Renal failure. The limited prognostic information available suggests that early diagnosis and appropriate treatment of infants and young children with classic Bartter Syndrome (type 3) may improve growth and perhaps neuro-intellectual development. On the other hand, sustained hypokalemia and hyperreninemia can cause progressive tubulointerstitial nephritis, resulting in end-stage renal disease (Kidney failure). With the early treatment of the electrolyte imbalances, the prognosis for patients with Classic Bartter Syndrome is good. Patients with Bartter syndrome type I and II tend to present a satisfactory prognosis after a median follow-up of more than 10 years.

• Bartter Syndrome usually occurs in childhood. Patient presents with the history of:
  • Constipation
  • Growth failure. The rate of weight gain is much lower than that of other children of similar age and gender.
  • Increased urinary frequency. The patient needs to urinate more often than usual.
  • Low blood pressure
  • Nephrolithiasis (Kidney stones)
  • Muscle cramping and weakness^[1]

• Bartter syndrome type I and type II are salt-wasting renal tubular disorders that are clinically characterized by polyhydramnios leading to premature delivery, marked polyuria, and a tendency towards nephrocalcinosis.^[2]
• Gallstones might represent a new complication of antenatal Bartter syndrome.^[3] Gallstone formation might result from an altered function of either the sodium–potassium–chloride cotransporter or the channel ROMK within the hepatobiliary system.^[3]
• Hypokalemia in Bartter syndrome can be exacerbated by electrolytes and fluid losses. Diarrhea, vomiting, alcohol abuse, cocaine, or other drugs result in electrolyte and fluid loss. Severe hypokalemia can lead to rhabdomyolysis, prolonged QT interval, life-threatening arrhythmia, syncope, and sudden death.^[4][5]
• Glomerular filtration rate of <90 mL/min/1.73 m2, sometimes associated with overt proteinuria.
• Prolonged hypokalemia can lead to interstitial fibrosis and tubular atrophy.^[6]
• Large amounts of calcium are lost through the urine (hypercalciuria), which can cause weakening of the bones (osteopenia).^[7]
• Untreated cases are associated with significant morbidity and mortality with a major contribution from chronic kidney disease. Kidney failure is a possible complication due to interstitial fibrosis, and may require renal replacement therapy.^[8]

• The prognosis is based on mutations or depends on the degree of the receptor dysfunction.^[8]
• The limited prognostic information available suggests that early diagnosis and appropriate treatment of infants and young children with classic Bartter Syndrome (type 3) may improve growth and perhaps neuro-intellectual development. On the other hand, sustained hypokalemia and hyperreninemia can cause progressive tubulointerstitial nephritis, resulting in end-stage renal disease (Kidney failure). With the early treatment of the electrolyte imbalances, the prognosis for patients with Classic Bartter Syndrome is good.
• Patients with Bartter syndrome type I and II tend to present a satisfactory prognosis after a median follow-up of more than 10 years.^[3]

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