From the Guidelines
Diagnosing acquired Bartter syndrome requires a comprehensive approach that includes clinical evaluation, laboratory tests, and exclusion of other causes, with a focus on identifying characteristic electrolyte abnormalities and renal salt wasting, as recommended by the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders 1. To diagnose acquired Bartter syndrome, the following steps should be taken:
- Evaluate the patient's medical history, including any history of polyhydramnios, premature birth, growth failure, and family history of similar conditions 1
- Conduct biochemical tests, including serum electrolytes, acid-base status, renin, aldosterone, creatinine, fractional excretion of chloride, and urinary calcium-creatinine ratio 1
- Perform a renal ultrasound to detect medullary nephrocalcinosis and/or kidney stones 1
- Consider genetic analysis to confirm the clinical diagnosis of Bartter syndrome, although this is not typically necessary for acquired forms 1 Key laboratory findings in acquired Bartter syndrome include:
- Hypokalemia and metabolic alkalosis
- Elevated renin and aldosterone levels
- Increased urinary excretion of potassium, sodium, and chloride
- Normal to low blood pressure It is essential to exclude other causes of hypokalemia and metabolic alkalosis, such as vomiting, laxative abuse, and Gitelman syndrome, and to consider the potential role of medications like loop diuretics, aminoglycosides, cisplatin, or amphotericin B in the development of acquired Bartter syndrome 1. The diagnosis of acquired Bartter syndrome should be based on a combination of clinical, biochemical, and sonographic findings, as outlined in the consensus and recommendations from the European Rare Kidney Disease Reference Network Working Group for Tubular Disorders 1.
From the Research
Diagnosis of Acquired Bartter Syndrome
To diagnose acquired Bartter syndrome, the following steps can be taken:
- Identify the clinical and biochemical alterations associated with the syndrome, including:
- Polyuria
- Dehydration
- Hypokalemia
- Hypochloremic metabolic alkalosis
- Hyperreninemia
- High levels of prostaglandins
- Normal or low blood pressure
- Hypercalciuria
- Failure to thrive 2
- Perform molecular studies to identify the subtype of Bartter syndrome, as different subtypes are caused by mutations in different genes, such as:
- BS type I: mutations in the gene encoding the luminal Na+-K+-2Cl- co-transporter
- BS type II: mutations in the gene encoding the luminal K+ channel ROMK
- BS type III: mutations in the gene encoding the basolateral chloride channel ClC-Kb (CLCNKB) 2
- Use the comprehension of renal physiology to guide the diagnosis and treatment, as limited clinical evidence for treatment is available 3
- Consider the use of nonsteroidal anti-inflammatory medications to control excessive renal prostaglandin E2 production, which can help reduce polyuria 2
Key Laboratory Findings
Key laboratory findings that can aid in the diagnosis of acquired Bartter syndrome include:
- Hypokalemia
- Hypochloremic metabolic alkalosis
- Hyperreninemia
- High levels of prostaglandins
- Hypercalciuria
- Normal or low blood pressure 2, 4
Genetic Causes
The genetic causes of Bartter syndrome have been identified, and mutations in several genes have been found to cause different subtypes of the syndrome, including: