Diagnosis and Management of Bartter Syndrome

Clinical Presentation and Diagnosis

The American Academy of Pediatrics and the European Society for Pediatric Nephrology recommend diagnosing Bartter syndrome clinically based on the triad of hypokalemic metabolic alkalosis, renal salt wasting with elevated fractional chloride excretion (>0.5%), and elevated renin-aldosterone, then confirming with genetic testing using a multi-gene panel 1, 2, 3
Severe polyhydramnios from excessive fetal polyuria is virtually pathognomonic for Bartter syndrome, particularly in the prenatal/neonatal period 4
Premature birth, typically between 29-35 weeks gestational age, is a common presentation in neonates with Bartter syndrome 4
Postnatal presentation includes renal salt wasting, severe polyuria, rapid weight loss, and dehydration 2, 3
Failure to thrive, recurrent vomiting, and repeated fever are common presentations beyond the neonatal period 1, 2, 3
Hypochloremic and hypokalemic metabolic alkalosis are characteristic biochemical findings in patients with Bartter syndrome 1, 2, 3
Nephrocalcinosis, particularly in Types 1 and 2, is a common complication of Bartter syndrome 1, 2, 3
Salt craving, muscle weakness, low blood pressure, and pubertal delay are also common features of Bartter syndrome 3
Rare presentations include hypokalemic paralysis or severe hypocalcemia with altered sensorium 5

The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend a comprehensive medical history assessment, including polyhydramnios during pregnancy, premature birth, growth failure, and developmental milestones 1, 2, 3
Biochemical parameters, including electrolytes (sodium, chloride, potassium, calcium, and magnesium), acid-base status, renin, and aldosterone levels, are crucial in diagnosing Bartter syndrome 1, 2, 3, 5
Urine studies, such as fractional excretion of chloride and urinary calcium-creatinine ratio, help distinguish between different types of Bartter syndrome 5
Imaging studies, including renal ultrasound, are recommended to detect medullary nephrocalcinosis and/or kidney stones 5

Genetic testing with a multi-gene panel is recommended for all patients with clinical suspicion of Bartter syndrome, with an analytical sensitivity of 90-100% and clinical sensitivity of ~75% in children 1, 2, 3, 5
The multi-gene panel should include genes such as SLC12A1, KCNJ1, CLCNKB, BSND, and MAGED2, which are associated with different types of Bartter syndrome 1, 2, 6
Genetic counseling should be offered to all affected families, including cascade screening of relatives 1, 2

Type	Age at Onset	Polyhydramnios	Calciuria	Key Features
Type 1 (SLC12A1)	Prenatal	Severe	High	Nephrocalcinosis after 1-2 months [1, 2, 4]
Type 2 (KCNJ1)	Prenatal	Severe	High	Nephrocalcinosis after 1-2 months [1, 2, 4]
Type 3 (CLCNKB)	0-5 years	Absent/mild	Variable	Later presentation [1, 2, 4]
Type 4 (BSND)	Prenatal	Very severe	Variable	Deafness, risk for CKD/ESRD [1, 2, 4]
Type 5 (MAGED2)	Prenatal	Present	High	Transient disease [1, 2, 4]

Diuretic abuse, laxative abuse, and vomiting should be excluded as acquired causes of hypokalemic metabolic alkalosis 4, 5, 6
Gitelman syndrome should be distinguished from Bartter syndrome based on hypocalciuria, hypomagnesemia, and milder symptoms 5, 6
Other considerations include congenital chloride diarrhea, pseudo-Bartter syndrome in cystic fibrosis, and pseudohypoaldosteronism type I 4, 5, 6

Tubular function tests with furosemide or thiazides should not be performed due to the risk of severe volume depletion 1, 2, 3, 7
Standard management of acute kidney injury (AKI) should not be assumed, as volume depletion from salt wasting requires salt supplementation, not restriction 5
Magnesium levels should not be overlooked, as severe hypomagnesemia can present as hypocalcemia and must be corrected for calcium to normalize 5
Potassium citrate should not be used for replacement, as non-chloride salts worsen the metabolic alkalosis 5