All::Nephrology::Diseases::Renal tubular acidosis
Intro
What is Renal tubular acidosis?
involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine
What are the investigations findings in Renal tubular acidosis?
- hyperchloraemic metabolic acidosis (normal anion gap)
- hypokalaemia (apart from Type IV which has hyperkalaemia)
Renal tubular acidosis type I
What are the main causes of Renal tubular acidosis type I?
- idiopathic
- rheumatoid arthritis
- SLE
- Sjogren's
- amphotericin B toxicity
- analgesic nephropathy
What is the pathophysiology of Renal tubular acidosis type I?
inability to generate acid urine (secrete H+) in distal tubule
What are the common complications of Renal tubular acidosis type I?
- nephrocalcinosis
- renal stones
Renal tubular acidosis type II
What are the main causes of Renal tubular acidosis type II?
- idiopathic
- as part of Fanconi syndrome
- Wilson's disease
- cystinosis
- outdated tetracyclines
- carbonic anhydrase inhibitors (acetazolamide, topiramate)
What is the pathophysiology of Renal tubular acidosis type II?
decreased HCO3- reabsorption in proximal tubule
What are the common complications of Renal tubular acidosis type II?
osteomalacia
Renal tubular acidosis type III
What is the pathophysiology of Renal tubular acidosis type III?
caused by carbonic anhydrase II deficiency
Which is the rarest type of Renal tubular acidosis?
Type III
Renal tubular acidosis type IV
What are the main causes of Renal tubular acidosis type IV?
- hypoaldosteronism
- diabetes
What is the pathophysiology of Renal tubular acidosis type IV?
reduction in aldosterone leads in turn to a reduction in proximal tubular ammonium excretion