lets CRACK RTA - kylie

[ArchivalUser]

hey guys I am starting discussing renal tubular acidosis here as it is HY and diff to understand.

[ArchivalUser]

RTA 1:
what I understand is
1)it is defect in H secretion
2)K is low or high
3)URINE pH>5.3
4)causes are .hereditary,lithium,amphotericin,sickle cell,autoimmune
5)treat with potassium citrate
6)complication is nephrolithiasis.
I do understand point 1.why is urine pH >5.3?and how does it cause renal stones>

[ArchivalUser]

renal stone is due to accompanied loss of Ca ++

[ArchivalUser]

y do we have osteomalcia in type 2 ?

[ArchivalUser]

RTA cracker ???

[ArchivalUser]

Hi, the real mechanism is not known. But this is the hypotheses found in most textbooks,
in type 1 there is acidosis in the blood so which decreases the secretion of citrate, hypocitrauria is a cause of nephrolithiasis as stated in Kaplan notes. In type 2, there is defect in ability to absorb HCO3 but at the same time citrate cannot be reabsorbed, so lots of citrate in the urine no nephrolithiasis.

[ArchivalUser]

I would say this mechanism is not important to remember cause it is just a hypothesis. Just remember 1 is associated with renal stones, 2 is associated with osteomalacia.

Rx is all the same bicarbonate in both cases with supplementation of electrolytes. In type 1 lots of bicarbonate(much more than type1 is needed -so diuretics which cause alkalosis is used to reduce the amount of bicarbonate needed.

Dx is acid load for both but for type II you have to add a base load to prove the defect is failure to absorb HCO3

do correct me if I am wrong.....

By Pray

[ArchivalUser]

Type 2 RTA is associated with Multiple Myeloma I think it is a important point to remember. in MKSAP there were 2 cases in which a old man coming in with back pain with RTA(no anion gap acidosis)--------------------Most likely diagnosis is MM----shoould start evaluation for MM