Week 4

Question 1

CKD (definition, ESRD, staging)

Answer 1

abnormalities of kidney structure/function present for >3 months, with implications for health

subset: ESKD – CKD severe enough to require replacement with dialysis or transplantation

staged by GFR. <60 is good predictor of stage 3-4. 5 is dialysis

Question 2

normal changes to kidneys with aging

Answer 2

• loss of ~1 mL/min each year starting ~40
• intimal fibrosis, loss of kidney mass
• decrease in ability for vascular auto-regulation

Question 3

factors associated with progression of CKD

Answer 3

• modifiable: BP, proteinuria, glycemia, smoking, dietary protein, anemia, obesity
• fixed: baseline GFR, age, genetics, sex, family history

Question 4

general effect of CKD on kidney function

Answer 4

• CKD kidney behaves as if it had fewer nephrons
• can maintain function until lots of damage done and/or pushed to limits

-despite decline in GFR, overall balance for Na, K, PO4 is maintained (can maintain steady-state).

Question 5

CKD and sodium balance

Answer 5

• each nephron is seeing more Na
• FeNa goes up –> new steady state at higher PNa
• Kidneys able to establish Na balance over range of intake, except at very low intake (because urea acts as osmotic diuretic).
• exception: comorbid HTN; still want to restrict Na

Question 6

CKD and potassium balance

Answer 6

• damaged kidneys retain intrinsic ability to excrete K (not effected by osmotic diuresis like Na).
• however, lots of CKD pts are given drugs that impair ability to excrete (diuretics) and are hypo-aldo, so get hyperkalemia

Question 7

water handling in CKD

Answer 7

• concentration is impaired but they’re generally OK b/c can excrete isosmotic urine
• diluting function intact

Question 8

two basic processes of dialysis

Answer 8

• ultrafiltration: remove extra fluid that accumulates to achieve “dry weight” (using pressure)
• Solute removal (using semi-permeable membrane)

Question 9

“dry weight” in dialysis

Answer 9

-pt’s baseline weight. accumulate extra fluid weight between treatments. ultrafiltration used to bring them back to dry weight

Question 10

types of dialysis conduits

Answer 10

• fistula: most desirable, natural tissue, longest lifespan, least chance of clotting, need great vessels
• grafts: less desirable, infection more common, by ready quicker
• catheter: can be used immediately (emergency), very susceptible to infection.