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Paradoxical hypertension and salt wasting in Type II Bartter syndrome.

Chan WK, To KF, Tong JH, Law CW - Clin Kidney J (2012)

Bottom Line: We report a low birth weight newborn baby who presented with repeated apnoea shortly after birth as well as hyponatraemia, hypochloraemia, hyperkalaemia and metabolic acidosis.Her biochemical features mimicked pseudohypoaldosteronism but with initial hypertension, which had not been described in BS.Her subsequent genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II BS.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, Queen Elizabeth Hospital, Hong Kong SAR, China.

ABSTRACT
Ante/neonatal Bartter syndrome (BS) is a rare hereditary disorder. It is characterized by renal salt wasting, hypokalaemic metabolic alkalosis, high renin and aldosterone but normal blood pressure. We report a low birth weight newborn baby who presented with repeated apnoea shortly after birth as well as hyponatraemia, hypochloraemia, hyperkalaemia and metabolic acidosis. Her biochemical features mimicked pseudohypoaldosteronism but with initial hypertension, which had not been described in BS. Her subsequent genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II BS.

No MeSH data available.


Related in: MedlinePlus

Mean arterial blood pressure measured from an indwelling arterial catheter over right radial artery of the patient in the first few days of life while her blood test showed hyponatraemia, hypochloraemia and polyuria. The arterial line had a good tracing and reflected a reliable blood pressure measurement.
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fig1: Mean arterial blood pressure measured from an indwelling arterial catheter over right radial artery of the patient in the first few days of life while her blood test showed hyponatraemia, hypochloraemia and polyuria. The arterial line had a good tracing and reflected a reliable blood pressure measurement.

Mentions: We describe a pre-term baby girl born at 35 weeks of gestation with birth weight 2.26 kg, Apgar Score 6 at 1 min and 9 at 5 min. The parents' marriage was non-consanguious and both were Chinese. The pregnancy was complicated by polyhydramnios detected since 28 weeks of gestation. After birth, she started feeding with usual infant formula (SMT™) and passed urine nine times per day. She developed several episodes of shallow breathing and apnoea at 24 h of life. These attacks were associated with oxygen desaturation and bradycardia but responded readily to tactile stimulation. Her oral feeding was poorly tolerated. To supplement her milk feeding, she was given intravenous fluid at 150 mL/day, with sodium concentration of 25 mmol/L and intravenous antibiotics were started empirically after sepsis work-up. The blood test revealed a serum sodium of 124 mmol/L (normal: 136–145 mmol/L) and potassium 6.8 mmol/L (normal: 3.5–5.1 mmol/L), urea 6.4 mmol/L (normal: 1.4–6.8 mmol/L) and creatinine 78 μmol/L (normal: 21–75 μmol/L). She was not oedematous. Her lowest serum sodium dropped to 113 mmol/L on Day 4, chloride 86 mmol/L (normal: 95–105 mmol/L) and bicarbonate 18 mmol/L (normal: 22–29 mmol/L). Her fluid intake, urine output and body weight in the initial few days of life are summarized in Table 1. Despite severe salt wasting and a weight loss of 14% within the first week, her blood pressure measured via intra-arterial line with good tracing was high for a premature baby at around 80/50 mmHg (Figure 1). She had a high urine output which ranged from 7.4–10 mL/kg/h and urine osmolality was low at 145–237 mosmol/kg. Urine sodium excretion ranged from 47 to 91 mmol/L, with increased fractional excretion of urinary sodium to 4–11%. Her morning cortisol was 556 nmol/L (normal spot cortisol at 7–10 am: 171–538 nmol/L), 17αOH progesterone was 3.2 nmol/L (normal: 0.5–20 nmol/L), aldosterone >3330 pmol/L (normal: <444 pmol/L) and plasma renin activity was extremely high such that it was out of the usual range for measurement in our laboratory. A random spot urine calcium creatinine ratio was 3.8 mmol/mmol Cr (normal: <0.7 mmol/mmol Cr). Serum magnesium was 0.69 mmol/L (normal: 0.62–0.91 mmol/L). Cranial ultrasound (USG) on Day 4 did not show any intra-cranial lesions or cerebral oedema. USG kidney on Day 19 showed bilateral nephrocalcinosis. She was treated with an NaCl supplement. Her serum sodium increased to 132 mmol/L by Day 8 of life but her serum potassium slowly dropped to a lowest of 2.6 mmol/L on Day 10 with increased transtubular potassium gradient at 6.9. Genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II Bartter syndrome (BS) (Figure 2a and b). The baby inherited an E151K missense mutation from her father and an in-frame deletion of four amino acids (ANHT) from her mother. Her condition was stabilized with sodium supplement at 10 mmol/kg/day, potassium supplement at 3.4 mmol/kg/day and indomethacin at 1.5 mg/kg/day. Her blood pressure slowly dropped back to the 90th percentile without any treatment. Her estimated glomerular filtration rate by Schwartz formula at 2 weeks of life was 33.3 mL/min/1.73 m2 (normal for age).


Paradoxical hypertension and salt wasting in Type II Bartter syndrome.

Chan WK, To KF, Tong JH, Law CW - Clin Kidney J (2012)

Mean arterial blood pressure measured from an indwelling arterial catheter over right radial artery of the patient in the first few days of life while her blood test showed hyponatraemia, hypochloraemia and polyuria. The arterial line had a good tracing and reflected a reliable blood pressure measurement.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400504&req=5

fig1: Mean arterial blood pressure measured from an indwelling arterial catheter over right radial artery of the patient in the first few days of life while her blood test showed hyponatraemia, hypochloraemia and polyuria. The arterial line had a good tracing and reflected a reliable blood pressure measurement.
Mentions: We describe a pre-term baby girl born at 35 weeks of gestation with birth weight 2.26 kg, Apgar Score 6 at 1 min and 9 at 5 min. The parents' marriage was non-consanguious and both were Chinese. The pregnancy was complicated by polyhydramnios detected since 28 weeks of gestation. After birth, she started feeding with usual infant formula (SMT™) and passed urine nine times per day. She developed several episodes of shallow breathing and apnoea at 24 h of life. These attacks were associated with oxygen desaturation and bradycardia but responded readily to tactile stimulation. Her oral feeding was poorly tolerated. To supplement her milk feeding, she was given intravenous fluid at 150 mL/day, with sodium concentration of 25 mmol/L and intravenous antibiotics were started empirically after sepsis work-up. The blood test revealed a serum sodium of 124 mmol/L (normal: 136–145 mmol/L) and potassium 6.8 mmol/L (normal: 3.5–5.1 mmol/L), urea 6.4 mmol/L (normal: 1.4–6.8 mmol/L) and creatinine 78 μmol/L (normal: 21–75 μmol/L). She was not oedematous. Her lowest serum sodium dropped to 113 mmol/L on Day 4, chloride 86 mmol/L (normal: 95–105 mmol/L) and bicarbonate 18 mmol/L (normal: 22–29 mmol/L). Her fluid intake, urine output and body weight in the initial few days of life are summarized in Table 1. Despite severe salt wasting and a weight loss of 14% within the first week, her blood pressure measured via intra-arterial line with good tracing was high for a premature baby at around 80/50 mmHg (Figure 1). She had a high urine output which ranged from 7.4–10 mL/kg/h and urine osmolality was low at 145–237 mosmol/kg. Urine sodium excretion ranged from 47 to 91 mmol/L, with increased fractional excretion of urinary sodium to 4–11%. Her morning cortisol was 556 nmol/L (normal spot cortisol at 7–10 am: 171–538 nmol/L), 17αOH progesterone was 3.2 nmol/L (normal: 0.5–20 nmol/L), aldosterone >3330 pmol/L (normal: <444 pmol/L) and plasma renin activity was extremely high such that it was out of the usual range for measurement in our laboratory. A random spot urine calcium creatinine ratio was 3.8 mmol/mmol Cr (normal: <0.7 mmol/mmol Cr). Serum magnesium was 0.69 mmol/L (normal: 0.62–0.91 mmol/L). Cranial ultrasound (USG) on Day 4 did not show any intra-cranial lesions or cerebral oedema. USG kidney on Day 19 showed bilateral nephrocalcinosis. She was treated with an NaCl supplement. Her serum sodium increased to 132 mmol/L by Day 8 of life but her serum potassium slowly dropped to a lowest of 2.6 mmol/L on Day 10 with increased transtubular potassium gradient at 6.9. Genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II Bartter syndrome (BS) (Figure 2a and b). The baby inherited an E151K missense mutation from her father and an in-frame deletion of four amino acids (ANHT) from her mother. Her condition was stabilized with sodium supplement at 10 mmol/kg/day, potassium supplement at 3.4 mmol/kg/day and indomethacin at 1.5 mg/kg/day. Her blood pressure slowly dropped back to the 90th percentile without any treatment. Her estimated glomerular filtration rate by Schwartz formula at 2 weeks of life was 33.3 mL/min/1.73 m2 (normal for age).

Bottom Line: We report a low birth weight newborn baby who presented with repeated apnoea shortly after birth as well as hyponatraemia, hypochloraemia, hyperkalaemia and metabolic acidosis.Her biochemical features mimicked pseudohypoaldosteronism but with initial hypertension, which had not been described in BS.Her subsequent genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II BS.

View Article: PubMed Central - PubMed

Affiliation: Department of Paediatrics, Queen Elizabeth Hospital, Hong Kong SAR, China.

ABSTRACT
Ante/neonatal Bartter syndrome (BS) is a rare hereditary disorder. It is characterized by renal salt wasting, hypokalaemic metabolic alkalosis, high renin and aldosterone but normal blood pressure. We report a low birth weight newborn baby who presented with repeated apnoea shortly after birth as well as hyponatraemia, hypochloraemia, hyperkalaemia and metabolic acidosis. Her biochemical features mimicked pseudohypoaldosteronism but with initial hypertension, which had not been described in BS. Her subsequent genetic study confirmed two novel heterozygous mutations in the Exon 5 of KCNJ1 compatible with Type II BS.

No MeSH data available.


Related in: MedlinePlus