Renal Tubular Acidosis Flashcards
Finding on ABG
Hyperchloraemic metabolic acidosis
Normal anion gap
Where does type 1 happen
Distal tubule
Why does type 1 happen
Inability to generate acid urine (secrete H+) in distal tubule
Complications of type 1 (2)
Nephrocalcinosis
Renal stones
Causes of type 1 (6)
Idiopathic RA SLE Sjogrens Amphotericin B toxicity Analgesic nephropathy
Which cause hypokalaemia
1, 2 and 3
Which cause hyperkalaemia
4
Where does type 2 happen
Proximal tubule
Why does type 2 happen
Decreased HCO3- reabsorption in proximal tubule
Complication of type 2
Osteomalacia
Causes of type 2 (6)
Idiopathic Fanconi syndrome Wilson’s disease Cystinosis Outdated tetracyclines Carbonic anhydride inhibitors
Where does type 3 happen
Mixed
What causes type 3
Carbonic anhydrase II deficiency
Where does type 4 happen
Collecting duct
Why does type 4 happen
Reduction in aldosterone —> reduction in proximal tubular ammonium excretion
Causes of type 4 (2)
Hypoaldosteronism
Diabetes
Type 1 urine pH
pH > 5.5
Type 2 urine pH
High pH initially but <5.5 later
Type 4 urine pH
pH <5.5
Type 1 primary defect
Impaired distal NH4+ secretion
Type 2 primary defect
Reduced proximal HCO3- reabsorption
Type 4 primary defect
Decreased aldosterone secretion or aldosterone resistance
