R2 Chronic Kidney Disease

Card Set Information

R2 Chronic Kidney Disease
2013-03-09 12:35:07
Renal II

Chronic kidney disease
Show Answers:

  1. Stages of Chronic Kidney Disease
    • 1. Kidney damage with normal or high GFR
    • -GFR ≥ 90 ml/min
    • -5.7% of US population

    • 2. Kidney damage with mild decrease in GFR
    • -GFR 60-89 ml/min
    • -5.4% of US population

    • 3. Moderate decrease in GFR
    • -GFR 30-59 ml/min
    • -5.4% of US population

    • 4. Severe decrease in GFR
    • -GFR 12-29 ml/min
    • -0.2% of US population

    • 5. Kidney Failure
    • -GFR <15 or Dialysis
    • -0.2% of US population
  2. Incidence of End-Stage Renal Disease (ESRD) by causes
    Dx of pts who start dialysis
    • Diabetes - 45%
    • HTN - 26.5%
    • Glomerulonephritis - 8.5%
  3. Adaptive changes in CKD
    Systemic complications
    Renal injury leads to adaptations by remaining nephrons that are initially protective, but eventually cause injury

    Hypertension - in the presence of CKD is bad prognostically

  4. Factors that may cause HTN in CKD
    • Impaired sodium excretion (expansion of ECF volume)
    • Activation of RAS (Direct vasoconstriction; sympathetic activation)
    • Sympathetic activation (Direct vasoconstriction; sympathetic activation)
    • Imbalance in prostaglandins or kinins (vasoconstriction)
    • Endothelin (Direct vasoconstriction; renal injury)
    • Reduced nitric oxide (Loss of vasodilator effects)
  5. HTN in CKD
    effect of lowering BP on glomerular capillary pressure
    • -Lowering BP does not necessarily lower PGC; triple therapy does not affect PGC
    • -ACE-Inhibitors do help lower PGC and Mean Arterial Pressure (MAP); "nephroprotective" drug

    ACE-Inhibitors can produce AKI, however: if BP drops to low, PGC will drop too low

    -Tight control on BP reduces risk for: diabetes=related mortality, stroke, microvascular damage, myocardial infarction (more than just CKD complications/progression)
  6. CKD
    glomerular capillary pressure
    Glomerular-capillary hypertension leads  to increased glomerular permeability to macromolecules

    -Increase filtration of plasma proteins --> Proteinuria
  7. Proteinuria and CKD
    • Rate of GFR decline increases as proteinuria increase
    • More protein in urine = more rapid decline in kidney function
  8. CKD and Aldosterone
    • Aldosterone levels correlate with rate of progression
    • Aldosterone levels are inversely related to GFR
    • Dietary protein raises aldosterone in renal disease
    • Aldosterone leads to fibrosis
    • ACE inhibitors lower aldosterone
    • -Aldosterone blocker side effect: hyperkalemia
  9. ACE inhibitors ('-prils')
    Benefit in CKD
    • Benefit beyond controlling HTN:
    • -Improved outcomes in nephropathy in type 1 diabetics; fewer progression to death, dialysis, or transplantation
  10. ARBs and CKD
    • irbesartan showed 70% reduction in risk for progression to overt diabetic nephropathy
    • -results independent of effects on systemic blood pressure

    Losartan improves outcomes (doubling of Cr, ESRD) compared to control

    • -These drugs work best if the BP is well controlled:
    • -MAP can be used to estimate decline in GFR per year (higher MAP, faster annual decline in GFR)
  11. Renal endocrinology
    calcium, phosphate balance
    Kidney is involved in the 1α hydroxilation of 25 VitD (from liver) into the active form: 1,25-Vit D

    • Regulation:
    • -hydroxilation rxn (generation of active Vit D) is promoted by low Ca2+, Low PO4, high PTH
    • -hydroxilation is inhibited by high Ca2+, high PO4, high 1,25-Vit D
  12. CKD effects on PTH
    -As GFR decreases, there is an inability to secrete phosphorus (PO4-); increase in PO4 causes a decrease in serum Ca2+ (PO4 binds Ca2+)

    • -Decrease in serum Ca2+ causes increase in PTH
    • -PTH has detrimental effects on bone (increases osteoclastic activity)

    • -Pts used to present with lytic bone lesions
  13. Limiting phosphate in CKD
    • -Increases serum Ca2+ in order to maintain goal PTH (150-300pg/ml)
    • -Goal PTH: stabilizes and improve bone architecture

    • -Oversuppression of PTH (<150pg/ml) can cause relative hypoparathyroidism and adynamic bone disease
    • -DM, age, aluminum, PTH resistance, malnutrition can also contribute to adynamic bone disease

    • Tx:
    • -limit phosphate intake in diet
    • -phoasphate binding agents (given at same time as meals)
    • -Vit D (increases serum Ca and reduces levels of PTH
  14. CKD
    tx of secondary hyperparathyroidism
    • -Goal PTH increases (and range broadens) with stage of CKD
    • -Treat acidosis
    • -Avoid aluminum overload
    • -Adjust dialysis calcium in ESRD

    • 1. Dietary PO4 restrictions; PO4 binders
    • 2. Vit D
    • 3. Calcimimetics - binds the calcium-sensing receptor (CaSR)
    • 4. Consider parathyroidectomy
  15. CKD and renal endocrinology
    Erythropoietin (EPO)
    Erythropoietin is made in the kidney; promotes production of RBC precursors and increases maturation of the burst forming unit-erythroid (BFU-E) and pro-erythroblast

    CKD or ESRD is often complicated by anemia

    Tx: target hemoglobin of 11-12g/dLany higher and pts have problems
  16. CKD and bleeding
    • Impaired platelet aggregation is common in CKD
    • -Abnormal vWF (various sized vWF fragments) are seen in CKD that (presumably) interfere with platelet adhesion

  17. CKD and GI bleeding
    factors that lead to GI bleeding
    • Renal failure:
    • -Abnormal platelet function
    • -Decreased degradation of gastrin → ↑acid → submucosal edema and hyperemia
    • -2o hyperparathyroidism → increased secretion → increased gastrin ...
    • -Increased Na retention, decreased albumin → submucosal edema and hyperemia
    • -Increased urea →decreased mucosal barrier
    • -Increased urea → increased urease→ irritability
  18. CKD and cardiovascular disease
    • CKD can cause CV disease → CV disease accelerates CKD

  19. Clinical evidence of renal failure
    • *Can have significant loss of function before sx appear
    • -Cr as a measure of GFR is inexact; GFR can vary while Cr stays the same (or relatively the same)
  20. Uremic syndrome
    uremic toxins and major manifestations
    • Uremic solute:
    • -Urea
    • -Creatinine
    • -Arginine
    • -Dimethylarginine
    • -Guanidinosuccinic acid
    • -β2-microglobulin
    • -Myoinositol
    • -Inositol
    • -PTH
    • -p-cresol sulfate
    • -Indican

    • Uremic syndrome manifestations:
    • 1. Nervous system - seizures, anorexia, RLS, asterixes
    • 2. MSK - weaknes, gout, renal osteodystrophy
    • 3. Hematologic - Anemia, bleeding disorders, leukocyte dysfunction
    • 4. Pulmonary - ARDS, pneumonitis, pleuritis
    • 5. CV - cardiomyopathy, arrhythmias, pericarditis
    • 6. GI - Anorexia, NausVom, GI bleeding
    • 7. Acid base/electrolytes - Anion gap acidosis, hyperkalemia, fluid overload
    • 8. Endocrine/metabolism - Hyperparathyroidism, insulin resistance
    • 9. Skin - pruritis, yellow pigmentation

  21. Clinical manifestations of CKD
    • General:
    • fatigue, weakness, lethargy
    • pruritis, pallor, petechiae
    • anorexia, nausvom
    • insomnia, irritability, paresthesia, asterixis, seizures, obtunded
    • dyspnea, peripheral edema, pericarditis, friction rub may be audible

  22. Neurological symptoms of CKD
    uremic syndrome
  23. GI symptoms of CKD
    Uremic syndrome
  24. Skin and peripheral neurological sx of CKD
    Uremic syndrome
  25. Lab findings in CKD
    • -Metabolic acidosis
    • -Hyperphosphatemia
    • -Hypocalcemia
    • -Electrolyte distrubances
    • -Normochromic, normocytic anemia
    • -Hyperuricemia
    • -Broad, waxy casts
    • -Periosteal erosions on plain film
    • -Small, echogenic (scarred kidneys)
  26. Renin-Angiotensin-Aldosterone System (RAAS)
    regulation of potassium excretion in the kidney
    Juxtaglomerular aparatus → Renin → Angiotensin I → Angiotensin II → binds Angiotensin receptors on adrenal gland → releases Aldosterone

    Aldosterone binds to aldosterone receptor in collecting duct, leading to K+ secretion

    Aldosterone blocking drugs (ACE inhibitors, ARBs, Aldosterone receptor blockers...)  can cause hyperkalemia hyperkalemia is a common cause of/finding in hospital admission

  27. Clinical strategies to slow progressive renal disease
    • Reduce systemic blood pressure (130/80), especially in DM
    • ACE-Inhibitors (Proteinuia <1000mg/day)
    • Administer ARB (Proteinuia <1000mg/day)
    • Reduce proteinuria (diet <1gm protein/kg body weight/day)
    • Blood glucose control (HgbA1c <7%)
    • Lipid-lowering agent (LDL <100mg/dL)
    • Miscellaneous (treat acidosis, corect calcium, phospohrus, vitamin D, and PTH)
    • Combination therapy (ACE-In, ARB, lipid-lowering, other antihypertensive)
  28. CKD and dialysis
    Principles, options for patients
    • Semipermeable membrane

    • 1. Hemodialysis
    • -need a high pressure/flow vein: "arteriolize" the vein (fistula, graft, or catheter)
    • -many more patients on hemodialysis (~350,000)

    • 2. Peritoneal dialysis
    • -peritoneum used as the semipermeable membrane; dialysate is pumped into peritoneal cavity
    • -pts can dialyse from home, even over night
    • -fewer patients on Peritoneal dialysis (~25,000)
  29. Renal transplant
    • Survival at 1 year: 95-98%
    • Survival at 10 years: 80%
    • ~165,000 transplants each year