| A Case of Type IV-4 Renal Tubular Acidosis |
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Young A Jo, Dong Un Kim, Yoon Kyung Lee, Byung Jun Choi, Jin Tack Kim, Ik Jun Lee |
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Department of Pediatrics, Catholic University Medical College, Seoul, Korea |
| IV-4형 신세뇨관성 산혈증 1례 |
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조영아, 김동언, 이윤경, 최병준, 김진택, 이익준 |
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가톨릭대학교 의과대학 소아과학교실 |
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| Abstract |
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Type IV renal tubular acidosis(RTA) is due to renal tubular bicarbonate wasting
associated with mineralocorticoid deficiency. In its five subtypes, IV-4 is due to
pseudohypoaldosteronism(PHA) evidenced by increased plasma renin and aldosterone.
PHA is believed to result from distal tubular unresponsiveness to circulating aldosterone
and has normal renal and adrenal fuction.
Hypoaldosteronism can easily be suspected when the patient shows typical electrolyte
imbalance (hyponatremia coupled with hyperkalemia) and the diagnosis of PHA is
confirmed by elevated serum aldosterone level. But some patients of PHA show
negligible electrolyte imbalance, thus metabolic acidosis is a sole abnormal finding in
routine laboratory examination.
We experienced a case of IV-4 RTA in a 2-month-old male infant who presented
with normal anion gap-metabolic acidosis as a sole abnormal finding in routine laboratory
examination. RTA was suspected and the test of urine pH during systemic acidosis and
fractional excretion of bicarbonate(FEHCO3
-) during the condition of normal plasma
bicarbonate concentration revealed the disease to be type IV RTA. With elevated plasma
renin activity and aldosterone level, the diagnosis of type IV-4 RTA (pseudohypoaldosteronism)
was made.
Type IV RTA is the most common form of RTA, therefore it is recommended that
young infants with suspected RTA should be checked for serum aldosterone level first. |
| Key Words:
Type IV-4 Renal Tubular Acidosis, Pseudohypoaldosteronism |
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