Renal tubular acidosis

Question 1

What is RTA?

Answer 1

Metabolic acidosis due to pathology in the tubules of the kidney

Question 2

Type 1 RTA
1) Type 1 RTA is due to a pathology where?
2) What is the consequence of a pathology in this area?
3) Name 3 causes of type 1 RTA
4) Name 2 ways it may present
5) Name 2 results of type 1 RTA
6) How is it treated?

Answer 2

1) Distal tubule
2) Distal tubule unable to excrete hydrogen ions
3) Genetic - autosomal dominant and recessive forms, SLE, Sjogren’s syndrome, primary biliary cirrhosis, hyperthyroidism, sickle cell anaemia, Marfan’s syndrome
4) Failure to thrive in children, hyperventilation to compensate for the metabolic acidosis, CKD, osteomalacia
5) Hypokalaemia, metabolic acidosis, high urine pH
6) Oral bicarbonate

Question 3

Type 2 RTA
1) Type 2 RTA is due to a pathology where?
2) What is a consequence of this?
3) What is the commonest cause
4) Name 2 results of type 2 RTA
5) How is it treated?

Answer 3

1) Proximal tubule
2) Proximal tubule is unable to reabsorb bicarbonate from urine into blood
3) Fanconi syndrome
4) Hypokalemia, metabolic acidosis and high urine pH
5) Oral bicarbonate

Question 4

What is type 3 RTA?

Answer 4

Combination of type 1 and type 2 with pathology in the proximal and distal tubule

Question 5

Type 4 RTA
1) What causes type 4 RTA?
2) Name 2 causes of this
3) It results in the same 3 things as type 1 and 2, but what else?
4) How is it managed?

Answer 5

1) Reduced aldosterone production
2) Adrenal insufficiency, medications i.e. ACEi, spironolactone, or systemic infections that affect the kidney i.e. SLE, HIV, diabetes
3) High chloride
4) Fludrocortisone