Proximal renal tubular acidosis and Fanconi syndrome
Introduction
Proximal renal tubular acidosis can occur isolated or associated with defects in the proximale tubule. Fanconi syndrome is the term for a patient with proximal renal tubular acidosis, glycosuria, aminoaciduria, hypouricemia, hypophosphatemia.
Causes
When the condition debuts in adulthood, monoclonal gammopathies are the most common cause of proximal tubule dammage. The syndrome can also be viewed as a side effect to a few medications. In children, familial and random gene defects must be considered as potential causes.
Table of the the most common causes of renal tubular acidosis and Fanconi syndrome:
| Causes |
Examples |
| Primary gene defects | Idiopathic |
| Familial |
| Acquired | Monoclonal gammopathies |
| Drugs |
| Heavy metals |
Clinical presentation
Renal tubular acidosis should be considered in patients with unexplained metabolic acidosis and a normal anion gap (hyperchloremic). In proximal RTA, the expected bicarbonate is 12-20 mmol/l and urin pH will be < 5,5, unlike in distal RTA where urine pH is > 5,5 and bicarbonate can often be < 10 mmol/l. In concurrent renal glycosuria, hypophosphatemia and/or hypouricemia, the patient has proximal RTA as a part of Fanconi syndrome.
Read more about renal tubular acidosis
UpToDate