| Abstract|| |
In this report, we present a case of a child with distal renal tubular acidosis, severe failure to thrive and profound rickets, who was only 7.8 Kg when presented at 6 years of age. His response to treatment and his follow-up for four years is discussed. Although failure to thrive is a common finding in renal tubular acidosis but the physical and x-ray findings in our case were unique.
|How to cite this article:|
Derakhshan A, Basiratnia M, Fallahzadeh MH, Hosseini-Al-Hashemi G. A Neglected Case of Renal Tubular Acidosis. Saudi J Kidney Dis Transpl 2007;18:585-9
|How to cite this URL:|
Derakhshan A, Basiratnia M, Fallahzadeh MH, Hosseini-Al-Hashemi G. A Neglected Case of Renal Tubular Acidosis. Saudi J Kidney Dis Transpl [serial online] 2007 [cited 2020 Jun 2];18:585-9. Available from: http://www.sjkdt.org/text.asp?2007/18/4/585/36516
| Introduction|| |
Renal tubular acidosis (RTA) was first described by Lightwood et al, in 1935  and Butler et al, in 1936  in children, and by Baines in 1945 in adults.  There are three main types of RTA, each type is either primary or secondary, besides several subdivision for each type., Recent advances of molecular basis of RTA have resulted in a better understanding of the disease and more therapeutic options than the mere oral alkali therapy.,
Failure to thrive is a common presentation of distal RTA but rickets is not as common. , We report here an interesting case of distal RTA with severe failure to thrive and profound rickets.
| Case report|| |
A six-year old boy referred with severe growth retardation and respiratory distress in June 2002. He was apparently well till five months of age, but he failed to thrive afterwards. There was a history of recurrent vomiting. Four siblings died at early life (no data available).
On physical examination, he was tachypnic, irritable, and cyanotic with severe deformity in chest cage and deformity of extremities [Figure - 1],[Figure - 2]. His parameters included weight 7.800 Kg, length 81 cm, head circumference 51 cm, blood pressure 80/50 mmHg, respiratory rate 35/min, pulse rate 90/min, and temperature 36.7 o C. Widening of wrist and deformity of knees and ankles were observed. The cardiac and abdomen exam were unremarkable.
The laboratory evaluations are summarized in [Table - 1], and revealed normal liver function test, urinalysis: RBC 4-5, WBC 8-10, Specific Gravity 1.002, Blood +1, urine pH 6.8, 24hr urine calcium 133 mg, serum creatinine 72 mg, and urine Na 26 mmol/L, K 20 mmol/L, Cl 33 mmol/L. Urine culture was negative. Renal ultrasound revealed normal size kidneys with severe increase in medullary echogenicity compatible with nephrocalcinosis, [Figure - 3]. Wrist x-ray revealed profound rickets [Figure - 2] and abdominal plain X-ray revealed nephrocalcinosis [Figure - 3] and severe osteopenia in all visualized bones. According to this presentation and investigations we diagnosed renal tubular acidosis.
Since the patient had a very low serum potassium level, potassium infusion and then sodium bicarbonate infusion were initiated as treatment of metabolic acidosis. After three days, his treatment was changed to polycitra (citric acid, sodium citrate and potassium citrate). Vitamin D was started from the beginning of treatment and was continued after discharge.
The course of the patient and follow up are summarized in [Table - 2], and his last follow up photograph was shown in [Figure - 4].
| Discussion|| |
Diagnosis of distal RTA is obvious with normal anion gap hyperchloremic metabolic acidosis, alkaline urine pH, positive urine anion gap, hypercalciuria and dramatic response to alkaline therapy in our case. ,,, Rickets in distal RTA could be treated with alkali therapy, without vitamin D, but the rickets in our case was so severe that we preferred to treat him with active vitamin D.
In a recent review, 5.6% of hospital admissions and/ or pediatric consultation were due to renal tubular acidosis.  Cases of distal RTA with hypokalemic paralysis and bony deformities and multiple bone fractures has been reported in the literature. ,, Although RTA is not a common renal cause of failure to thrive, it should be considered when we are confronted with children who have developed significant growth retardation, tubular dysfunction, polyuria, refractory rickets and hypokalemic metabolic acidosis. 
Our case is unique in that at his six years of age, he was just 7.8 Kg in weight, 81 cm in length and did not seek medical advice so far.
| Acknowledgement|| |
The authors would like to thank Dr. Davood Mehrabani, Miss Gholami and Mrs. Ghorbani at Center for Development of Clinical Research of Nemazee Hospital for editorial and typing assistance.
| References|| |
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Pediatric Office, Nemazee Hospital, Shiraz University of Medical Sciences, Post -Code: 71937-11351, Shiraz
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]
[Table - 1], [Table - 2]