Renal Tubular Acidosis

Question 1

What is this?

Answer 1

metabolic acidosis due to pathology in the kidney tubules

Question 2

how many types are there?

Answer 2

Type 1-4

• 1&4 are most relevant to exams and clinical practice

Question 3

Pathology of type 1?

Answer 3

• pathology is in the DISTAL TUBULE
  
  • inability to excrete H+

Question 4

causes of T1?

Answer 4

• genetic mutation
• SLE
• sickle cell anaemia
• marfan’s
• hyperthyroidism
• PBC
• Sjogren’s

Question 5

Presentation of T1?

Answer 5

• FTT in kids
• CKD
• hyperventilation in response to the acidosis
• bone disease (osteomalacia)

Question 6

Results of T1?

Answer 6

• metabolic acidosis
• hypokalaemia
  
  • as K+ cannot be reabsorbed
• high urinary pH

Question 7

Mx for T1?

Answer 7

oral bicarbonate

Question 8

Pathology in T2?

Answer 8

pathology is in the proximal tubule- inability to reabsorb bicarbonate

Question 9

cause of T2?

Answer 9

main cause is Fanconi Syndrome

• linked to Ashkenazi Jews
• causes BM failure, AML and other cancers

Question 10

Results of T2?

Answer 10

• metabolic acidosis
• hypokalaemia
• high urinary pH

but also…

• glycosuria
• phosphaturia
• aminoaciduria

Question 11

Mx of T2?

Answer 11

oral bicarbonate

Question 12

type 3 pathology?

Answer 12

mixture of T1&T2

Question 13

Type 4 pathology?

Answer 13

reduced aldosterone

Question 14

Causes of T4?

Answer 14

• adrenal insufficiency
• drugs
  
  • ACEI / Spironolactone
• systemic diseases that affect kidneys
  
  • SLE/Diabetes/HIV

Question 15

Results of T4?

Answer 15

• metabolic acidosis
• hyperkalaemia
• low (acidic) urinary pH
  
  • hyperkalaemia suppresses ammonia production

Question 16

Mx of T4?

Answer 16

• fludrocortisone
• oral sodium bicarbonate + treatment of hyperkalaemia