| Abstract|| |
Early diagnosis of Bartter syndrome (BS) in the neonatal period is a clinical challenge, more so in an extremely low birth weight (ELBW) baby because of the inherent renal immaturity and the associated difficulty in fluid management. However, once a diagnosis is made, the disorder is known to respond well to fluid and electrolyte management, prostaglandin inhibitors, and potassium-sparing diuretics. Herein, we report a case of neonatal BS in a very premature ELBW infant.
|How to cite this article:|
Hegde D, Mondkar J, Abdagire N. Neonatal bartter syndrome in an extremely low birth weight baby. Saudi J Kidney Dis Transpl 2017;28:1162-4
|How to cite this URL:|
Hegde D, Mondkar J, Abdagire N. Neonatal bartter syndrome in an extremely low birth weight baby. Saudi J Kidney Dis Transpl [serial online] 2017 [cited 2020 Sep 29];28:1162-4. Available from: http://www.sjkdt.org/text.asp?2017/28/5/1162/215121
| Introduction|| |
Antenatal Bartter syndrome (BS) is a rare autosomal recessive, renal tubular disorder that can lead to fetal polyuria, severe hydramnios, and premature delivery. Failure to thrive, polyuria, episodes of dehydration, hypercalciuria, and nephrocalcinosis characterize the postnatal course. Early diagnosis in an extremely low birth weight (ELBW) neonate can be challenging because of the renal immaturity that causes electrolyte disturbances and fluid loss. This case highlights the importance of keeping a high index of suspicion in ELBW babies having polyuria and suggestive acid-base disturbance.
| Case Report|| |
A baby girl born by precipitate labor at home at 26.4 weeks of gestation was brought at 12 h of life. She was born of a consanguineous marriage to a multigravida mother (G5P3L2 A2). Although the mother was registered, no antenatal sonography was done. The baby’s birth weight was 850 g, length 35 cm, and head circumference 27 cm. At admission, she was started on empirical antibiotics (cefota-xime and amikacin) and intravenous fluids. On the 3rd day of life, she developed tachycardia and dehydration though adequate fluids were being given. She was polyuric (urine output 9 mL/kg/h). Her renal profile and blood sugar were normal, and she was normotensive. Urine specific gravity and osmolality were 1.003 and 305 osmol/L, respectively. Ultrasound of the kidneys showed no evidence of nephrocalcinosis. Investigations revealed hypochloremic, hypokalemic metabolic alkalosis with hyponatremia (serum sodium 106 mEq/L, potas-sium 2 mEq/L, chloride 65 mEq/L, bicarbonate 29.6 mmol/L, and pH 7.568). Neonatal BS was suspected, and sodium correction and potassium supplementation were started, but hyponatremia, hypokalemia, metabolic alka-losis, and polyuria persisted through day 4, 5, and 6 of life. She was put on continuous positive airway pressure for recurrent apnea on day 7. Sepsis screen was negative. Serum calcium was 6.9 mg/dL and urine showed hyper-calciuria (urine calcium: creatinine ratio 2.56). The diagnosis of BS was confirmed when plasma renin activity was seen to be high (6.85 ng/mL/h for a normal reference range of 0.5–1.9 ng/mL/h). Injection Indomethacin was started at 0.1 mg/kg 12 hourly intravenous, but the dose had to be gradually increased to 0.25 mg/kg/dose 12 hourly by day 9 as hypokalemia and polyuria persisted (serum K+ 1.56 mEq/L). Hypokalemia was corrected only on addition of spironolactone on day 11. Indomethacin was changed to oral at a dose of 1 mg/kg/dose once a day, once she was started on feeds. The baby was discharged after a neonatal intensive care unit stay of 56 days on oral indomethacin (pulverized sachets) and potassium supplements.
| Discussion|| |
BS is an autosomal recessive renal tubular disorder characterized by hypokalemic hypo-chloremic metabolic alkalosis, hyperreninemia, hyperprostaglandism, normal blood pressure with increased urinary loss of sodium, potassium, calcium, and prostaglandin. Fanconi et al in 1971 were the first to report the neonatal variant of BS in two patients with hyper-calciuria and nephrocalcinosis. Both were born prematurely and had hydramnios in the antenatal period. A recent study reported six cases of antenatal BS, all born prematurely with associated polyhydramnios. We presume that prematurity and precipitate labor in our patient was due to polyhydramnios. Hydram-nios is due to fetal polyuria. The continued polyuria in postnatal life leads to dehydration and renal salt wasting and contributes to growth retardation. Hypercalciuria may lead to early-onset nephrocalcinosis.
BS is now classified into five types: (1) neonatal (Types I and II), (2) classic type (Type III), and (3) neonatal with sensorineural deafness (Types IV and V)., The disorder has very rarely been described in extremely premature babies. The postnatal course in these neonates is compounded by hyposthenuria, electrolyte disturbances, and physiological weight loss making early diagnosis a difficult task.
The differential diagnosis of BS includes Gitelman syndrome (characterized by hypo-magnesemia and hypocalciuria), pseudohyper-aldosteronism (hypertension with no evidence of increased secretion of mineralocorticoids), and pseudo-BS due to administration of high doses of prostaglandin E1.
Prenatal diagnosis is possible by demonstrating high chloride content in the amniotic fluid. Antenatal Indomethacin and serial amnio-centesis may postpone premature delivery by controlling polyhydramnios. However, caution needs to be exercised when indomethacin is used antenatally as it can close the ductus arteriosus prematurely, thereby necessitating echocardiographic monitoring. Indomethacin given to the mother can also lead to serious postnatal complications such as oliguric renal dysfunction, necrotizing enterocolitis, and ileal perforation. Spontaneous colonic perforation has also been reported.
Therapeutic efforts are directed at correction of dehydration and electrolyte imbalance. High doses of potassium are necessary to correct hypokalemia. Administration of Indomethacin in a dose of 1–5 mg/kg/day is seen to be beneficial. Addition of a potassium-sparing diuretic like spironolactone is a useful adjunct, but effects are transient. Our patient received potassium in very high doses, and an early diagnosis enabled early institution of Indomethacin. However, hypokalemia responded only after the addition of Spironolactone. We present this rare case for the challenges in the early identification of the problem and fluid and electrolyte management.
| References|| |
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Department of Neonatology, Lokmanya Tilak Municipal Medical College and Hospital, Sion, Mumbai - 400 022, Maharashtra