Renal: RTA

Question 1

what is RTA in general
-results in?
-types and their basic pathos
-

Answer 1

-group of diseases causing a NON-AG metabolic acidosis—-with specific CM for each type

type 1: distal RTA
*impaired renal H+ excretion–>distabl tubule cannot acidify the urine-hypokalemia and acidic urine pH

type 2: Proximal RTA

• impaired HCO3- resoprtion
• hypokalemia
• alkaline OR acidic urine pH

type 4: hypo-aldosterone state

• hyperkalemia
• assoc with DM

Question 2

name the types

Answer 2

type 1: distal RTA
type 2: proximal RTA
type 4: hyperkalemic RTA

Question 3

RTA type 1

Answer 3

H+ secretion impaired–acidification problem

• hypokalemia
• urine pH >5.5
• metabolic acidosis

PRIMARY
*familial or idiopathic

SECONDAY:

• autoimmune—RA, sjorgens
• drugs: ibuprofen, lithium, amophtericin
• hypercalciruia
• misc: obstructive uropathy, medullary sponge kidney

CM

• nephrolithiasis bc urine ph HIGH and incr bone turnover and nephrocalcinosis
• hyPOK
• HYPERchloremia
• HYPER-calcemia

Question 4

RTA Type 2

Answer 4

**defect in prox tubule reabsoprtion of HCO3–> BICARB LOSS PROBLEM

> > > > > bicarb loss versus type 1
urine pH may be > or <5.5 (variable)

incr risk for Hypo-phosphatemic rickets

CAUSES

• Fanconi syndrome
• carbonic anhydrase inhibitors

Question 5

RTA type 4

-mcc

Answer 5

MCC=DM
others: meds: NSAIDs, ACEi, arbs, heparin-LMW, obstructive nephropathy, primary adrenal insuff, sickle cell nephropathy

kidneys cannot excrete NH4
-aldosterone deficinecy or resistence to aldosterone

CAN acidify the urine—–urine PH is low in the setting of metabolic acidosis

Hyperk*
hypercl-

Question 6

appraoch to dx RTA

Answer 6

1. has to be metabolic acidosis
2. calculate AG—>it will be normal (10-12)
3. look at serum K+
   * if K+ is LOW= types 1-3
   * if K+ HIGH= 4
4. Look at urine PH–>
   * ph >5.5= distal type 1
   * ph <5.5= type 2 or 4

Question 7

urineAG and RTA

(-) means?

Answer 7

negative=means no RTA bc this is normal

positive= RTA–means there is not enough NH4 avaible to buffer the acids and HCO3 is high in the urine

Question 8

TX for:

type 2

Answer 8

TYPE 2

• large amts of HCO3 or Nacitrate
• thiazides
• vit d and phosphate rxs if they have Fanconi syndrome

type 1

• less HCO3 than proximal type 2
• monitor for s/s of nepthrolithiasis,
• might need thiazides

type 4
-may require K+ binding resins