CKD Flashcards
Definition of CKD
Abnormality of kidney function or structure that is present for at least 3 months
- persistently abnormal function (GFR<60) due to intrinsic kidney disease
OR
- normal function but persistent structural abnoramility of the kidneys with markers of damage (proteinuria, hematuria, casts)
Screening for CKD
How often should you test after an abnormal result?
- Serum creatinine
- ACR
- Urinalysis
+/- 4. U/S
- repeat testing 3-6 months or sooner if severe
- need to screen diabetics annually
Common causes of CKD
Higher risk ethnicities
- Most common cause is DM
- HTN, ischemic, glomerulonephritis, polycystic kidney disease, drugs, pyelonephritis, AKI, NSAIDs
- Smoking, sleep apnea
- South asian, pacific islanders, indigenous
Uremic syndrome
- when does it occur
- sx
- Symptomatic around <30 eGFR, predominates at <15
- fatigue, nausea, anorexia, amenorrhea, cold intolerance, leg cramps and restlessness, wasting, pruritis, constipation, edema/SOB, CHF, HTN
Common comorbidities with CKD
- anemia, hyperkalemia, acidemia, hyperparathyroidism, hyperphosphatemia
- ESRD is actually very uncommon in CKD/DKD as most patients will die before progressing to the need for dialysis
BP goals for CKD and CKD with DM
Careful rule to avoid with HTN drugs?
Which BP drug is first line?
Which BP drug has a risk of hyperkalemia?
- under 135/85
- under 130/80 if diabetic
- DO NOT combine and ACEi and ARB
- thiazides are first choice
- spironolactone is effective but there is a risk of hyperkalemia
When is metformin contraindicated in CKD?
eGFR <30
Bacteria present but no WBC?
NOT an infection, likely contamination
What values would suggest severe CKD?
- ACR
- Protein dipstick
- PCR
- 24h protein
- ACR 30+
- 1+ or more protein
- PCR 50+
- 24h protein 300+
How do _____ affect the AA/EA?
- NSAIDs
- ACEIs/ARBs
- ANP/prostaglandin/ATII/NE
- NSAIDs constrict the AA and ACEI/ARBs dilate the EA (decrease GFR)
- ANP/prostaglandin dilates AA and ANP/ ATII/NE constricts EA (increase GFR)
How does PTH affect Bone/ Kidney/ Intestine?
Bone –> increases calcium and PO4 resorption
Kidney –> increases calcium resorption, increases PO4 excretion (indirect), increases calcitriol activation
Intestine –> indirectly increases calcium and PO4 absorption by increasing calcitriol
- overall increases serum calcium and neutral/ mildly decreases serum PO4
- PTH effect on PO4 renal excretion overrides its own bone and intestine effects as well as the calcitriol effect of increasing PO4 resorption
How does calcitriol affect Bone/ Kidney/ Intestine?
Bone –> increases calcium and PO4 resorption
Kidney –> increases calcium and PO4 resorption
Intestine –> increases calcium and PO4 absorption
- overall increases serum calcium and PO4
How does FGF-23 affect Bone/ Kidney/ Intestine?
Bone –> unknown
Kidney –> increases PO4 excretion, decreases calcitriol activation
Intestine –> indirectly decreases calcium and PO4 absorption by decreasing calcitriol
*overall decreases serum PO4 and calcitriol
Stimulation vs inhibition of PTH?
(+) –> decreased calcium, increased PO4
(-) –> increased calcium, calcitriol, FGF-23
Stimulation vs inhibition of calcitriol?
(+) –> decreased PO4, increased PTH
(-) –> increased PO4, FGF-23
Stimulation of FGF-23?
(No knowledge on what inhibits it)
increased PO4, calcitriol, PTH
How does CKD mineral bone disease affect the balance of Ca/calcitriol/PTH, etc?
hyperphosphatemia, hypocalcemia, decreased calcitriol, and PTH resistance to calcium ALL lead to SECONDARY HYPERPARATHYROIDISM
How does CKD mineral bone disease affect the balance of Ca/calcitriol/PTH, etc?
hyperphosphatemia, hypocalcemia, decreased calcitriol, and PTH resistance to calcium ALL lead to SECONDARY HYPERPARATHYROIDISM
Treatment for CKD mineral bone disease?
- limit hyperPO4 using binders (Tums, Fe, Mg) and diet, consider supplementing calcitriol, consider calcimimetic if on dialysis ( will increase Ca sensitivity), maintain target PTH for CKD stage
What is calcitriol? What is its role in CKD?
- main active vitamin D metabolite
- helps overcome skeletal resistance to PTH that occurs with CKD
Describe process of Diabetic Kidney Disease
What is a good predictor of mortality?
- GFR will initially increase (hyperfiltration) –> microalbuminuria –> proteinuria –> nephrotic syndrome –> decreased GFR
–> ESRD
*faster if diabetic
Silent –> mild GBM thickening, focal mesangial sclerosis
Incipient –> moderate GBM thickening, variable sclerosis, moderate albuminuria, mild GFR decrease
Overt –> severe albuminuria, HTN, decreased GFR, marked sclerosis
ESRD –> global sclerosis, GFR<15, HTN, decreasing albuminuria
*albuminuria predicts CV mortality - closely related to vascular disease due to endothelial dysfunction leading to protein leak
Describe pathology in the kidney with DKD
- mesangial expansion and proliferation
- GBM thickening
- podocyte loss, hypertrophy, foot process effacement
- glomerulosclerosis
- increased ROS (TGF-B, IL1/6/18, TNF-a) from the PKC/ polyol/ RAAS pathways
*oxidative stress is central to the damage caused by hyperglycemia