Renal tubular disease Flashcards
what is renal tubular acidosis
metabolic acidosis causes by impaired secretion by the kidney. hyperchloraemic metabolic acidosis with normal anion gap
how many types of RTA are there
4
where is type 1 RTA
distal
what is type 1 RTA
inability to excrete H+ and generate acidic urine in distal tubule
causes of type 1 RTA
inherited disorders, SLE, Sjogrens, drug related
features type 1 RTA
rickets, osteomalacia (as buffering H+ with calcium). nephrocalcinosis with renal calculi, recurrent UTIs
tests type 1 RTA
urine PH >5.5 despite met acidosis
treatment type 1 RTA
oral sodium bicarbonate or citrate. ESRF may result from nephrocalcinosis
where is type 2 RTA
proximal
what is type 2 RTA due to
bicarbonate leak- defect in the HCO3- reabsorption in proximal tubule leading to excess HCO3- in the urine pH >5.5 leading to a metabolic acidosis
which is rarer type 1 or 2
type 2- assoc with a more generalised tubular defect
what is common in type 2 RTA
hypokalaemia- due to osmotic diuretic effect of decr HCO3- reabsorption, causing incr flow rate to distal tubular and incr K+ excretion
treatment type 2
high doses bicarbonate >10mmol/kg/day
what is type 3 RTA
rare combination of types 1 and 2
what is type 4 RTA
hyperkalaemic. due to hyporeninaemic hypoaldosteronism. decr K+ and H+ excretion
causes of type 4
Addisons, diabetic nephropathy, interstitial nephritis, drugs (K+ sparing diuretics, b blockers, NSAIDs)
treatment type 4
remove any cause. fludrocortisone 0.1mg, furosemide, or calcium resonium
what is Fanconi syndrome
proximal tubular dysfunction leading to loss of amino acids, glucose, PO4^3-, and HCO3 in urine
what does Fanconi cause
dehydration, metabolic acidosis (type 2 RTA), osteomalacia/rickets, electrolyte disturbances
what are the causes of Fanconi
congenital- idiopathic, Wilsons, tyrosinaemia, Lowe syndrome. Acquired- heavy metal poisoning, drugs, Sjogrens
treatment Fanconi
remove cause replace losses. K+, sodium bicarb, PO4^3- and vit D supplements
what is cystinosis
accumulation cysteine in lysosomes due to autosomal recessive defect
what can cysteine deposits cause
Fanconi syndrome, visual impairment, myopathy, hypothyroidism, ESRF.
treatment cystinosis
oral cysteamine. remove cause and replace losses
what are the Hereditary Hypokalaemic Tubulopathies
Bartter syndrome, and Gitelman syndrome
what is Bartter syndrome an inherited mutation in
co transporter targeted by LOOP diuretics
what is Gitelmans syndrome a mutation in
co transporter targeted by THIAZIDE diuretics
what does Bartter syndrome involve
low K+, metabolic alkalosis, hypercalciuria
what does Gitelmans syndrome involve
low K+, metabolic alkalosis and hypocalciuria and low Mg2+
