RTA AB

Question 1

Proximal (type 2) RTA - underlying pathophysiology?

Answer 1

Reduced bicarbonate reabsorption in the PCT

Question 2

Proximal (type 2) RTA - urine pH?

Answer 2

Urine pH

Question 3

Fanconi syndrome - what are the features?

Answer 3

Proximal RTA
Proteinuria - LMW
Phosphaturia
Glycosuria

Also mild hpokalaemia (secondary hyperaldosteronism)

Question 4

Proximal (type 2) RTA - management?

Answer 4

Alkali therapy + thiazide

Question 5

Proximal (type 2) RTA - causes?

Answer 5

Medications - Tenofovir, Ifosfamide
Amyloidosis, Multiple Myeloma
Kidney transplant
Heavy metal toxicity
Cystinosis
Wilson disease

Question 6

Distal (type 1) RTA - underlying pathophysiology?

Answer 6

Impaired excretion of hydrogen ions

Question 7

Distal (type 1) RTA - urine findings?

Answer 7

pH >5.5

Nephrocalcinosis (due to increased urine pH and decreased level of urine citrate)

Question 8

Distal (type 1) RTA - laboratory findings?

Answer 8

Hypokalamia

Normal anion gap metabolic acidosis

Question 9

Distal (type 1) RTA - management

Answer 9

Correct hypokalaemia before correcting acidosis

Question 10

Distal (type 1) RTA - acquired causes?

Answer 10

Autoimmune - Sjogren, SLE, RA
Cirrhosis
Medications - Amphotericin B, Ifosfamide, Lithium
Hypercalciuria

Question 11

Type 4 RTA - laboratory findings?

Answer 11

Hyperkalaemia

Normal anion gap metabolic acidosis

Question 12

Type 4 RTA - what are the two mechanisms?

Answer 12

1. Hypoaldosteronism
   - CNI
   - Aldosterone antagonists
   - Pseudohypoaldosteronism
   - Drugs that block ENAC - Amiloride, Pentamidine

or

2. Tubulointerstitial injury
   Urinary tract obstruction
   Chronic interstitial nephritis
   Sickle cell nephropathy