ESPE Abstracts

Brief summary: This case series of three patients with Bartter syndrome (BS) type 3 treated in Sao Paulo and Santarem, Brazil is presented to highlight the difficulties of clinical management and diagnosis. BS is an inherited disorder characterized by impaired sodium chloride reabsorption in the cortical and medullary thick ascending limbs of the loop of Henle and secondary hypokalemic alkalosis. In Brazil, genetic testing for this disease is not common. However, one benefit of genetic testing is that it can aid in avoiding aggressive treatment for individuals with transient BS type 5 and to identify infants with BS type 4a/b. This case series describes the care of three children born with BS type 3 at two hospitals in Sao Paulo and Santarem, Brazil between 1998 and 2022. Consanguinity was present in two families. All three children had homozygous deletions in CLCNKB, severe short stature, neurodevelopmental delay and were referred to Sao Paulo’s institution for molecular analyses at 1, 8 and 14 years of age. The 8-year-old patient had short stature (-3,5 SD) and, unlike what is observed in the literature, was born prematurely and extremely underweight and in addition to this presented with hypercalciuria, nephrocalcinosis and chronic kidney disease. The patient was treated with potassium supplementation, spironolactone and recombinant GH (rhGH). The 14-year-old patient was born appropriate for gestacional age and had severe short stature (-4.3 SD) and hypokalemia (1.3 mEq/l). This patient was treated for two years with high-dose potassium supplements, spironolactone and rhGH but died two years after starting treatment. The child aged 1 year and 5 months was born small for gestational age and had length less than 3th percentile. This patient had severe short stature (-5.8 SD) and presented with the following characteristics: high anterior hairline, frontal bossing, postnatal microcephaly, hypokalemia, hyponatremia, dyslipidemia and died three months after the first assessment. Persistent growth failure despite adequate treatment of metabolic disturbances has been repeatedly reported in BS, especially in BS type 3. It remains unclear whether poor growth is due to acid/base or electrolyte disturbances in BS or whether it is an intrinsic part of the disorder. The authors advocate for an improvement in multidisciplinary support for these patients and the urgent need for endocrinologists to be better prepared to evaluate clinical, laboratory and molecular genetic diagnoses to optimize patient outcomes.