Renal - Renal Tubular Acidosis Flashcards
What is renal tubular acidosis?
Metabolic acidosis due to pathology in the tubules of the kidneys
Complete the table
What is the most common type of renal tubular acidosis?
Type 4
Outline Type 1 renal tubular acidosis
Distal tubule cannot excrete hydrogen ions
This causes
- High urinary pH due to absence of H+ ions
- Metabolic acidosis -retained H+ ions
- Hypokalaemia, failure of the H+K+ATPase
What conditions can cause renal tubular acidosis type 1?
SLE
Sjogren’s syndrome
Primary biliary cholangitis
Hyperthyroidism
Sickle cell anaemia
Marfan’s syndrome
How does renal tubular acidosis type 1 present?
Failure to thrive in children
Recurrent UTIs (due to alkaline urine)
Bone disease (rickets of osteomalacia)
Muscle weakness
Arrhythmias
How is renal tubular acidosis type 1 treated?
Oral bicarbonate to correct acidosis and electrolyte imbalance
When does Type 2 renal tubular acidosis occur?
Proximal tubule cannot reabsorb bicarbonate from urine
What does type 2 renal tubular acidosis lead to?
High urinary pH (excess bicarbonate in urine)
Metabolic acidosis (inadequate bicarbonate in the blood)
Hypokalaemia (loss of potassium along with bicarbonate)
What are some key causes of renal tubular acidosis type 2?
Inherited
Multiple myeloma
Fanconi’s syndrome
How is type 2 renal tubular acidosis treated?
Oral bicarbonate
What is type 3 renal tubular acidosis?
Rare condition
Combination of type 1 and 2 RTA
What is type 4 renal tubular acidosis?
Caused by reduced aldosterone
Aldosterone leads to increased ENaC and RomK channels so impaired aldosterone reduces H+ and K+ excretion
Ammonia produced in distal tubules to balance H+ excretion to prevent urine from being too acidic
Hyperkalaemia suppresses ammonia production so urine becomes acidotic
What does type 4 renal tubular acidosis result in?
Metabolic acidosis (retained H+ ions in blood)
Hyperkalaemia
Low urinary pH
What can cause low aldosterone?
Adrenal insufficiency
Diabetic nephropathy
ACEi
Spironolactone
Eplerenone
