CKD And Renal Replacement Therapies

Question 1

In development of CKD, _____ is an initially appropriate adaptation but ultimately becomes maladaptive as it leads to sclerosis and decrease in number of nephrons d/t distortion of renal architecture, abnormal podocyte function, and disruption of filtration barrier

____ is also involved in initial protective increase in filtration, but worsens hypertrophy and sclerosis over time

Answer 1

Hyperfiltration

RAAS

Question 2

Most common diseases associated with CKD

Answer 2

Diabetes and HTN = most common

Others: glomerulonephritis, ADPKD, other cystic and tubulointerstitial nephropathies

Question 3

What parameter is used to define and stage CKD?

Answer 3

GFR

[contrast to AKI which is defined and staged by rate of rise in serum creatinine]

Question 4

Normal GFR is ~100

Define GFR changes in stages of CKD

Answer 4

Stage 2: GFR 60-89

Stage 3: GFR 30-59

Stage 4: GFR 30-44

Stage 5: GFR <15 (renal failure)

Question 5

Progressive lab changes/clinical features in worsening stages of CKD

Answer 5

Stage 2, or GFR ~80 = HTN

Stage 3, or GFR ~30-60 = elevated PTH, anemia, hyperphosphatemia, hyperkalemia, possible mild uremic syndrome

Stages 4-5, or GFR <30 = all of the above changes + acidosis + uremic syndrome

Question 6

How does sodium change in CKD?

Answer 6

ECV increases as Na excretion decreases (so lab levels may appear normal)

This worsens HTN and often requires diuretic therapy

Question 7

Potassium is typically unaffected in CKD except under what circumstances?

Answer 7

Dietary changes!

If there is an increase in dietary intake, consider potassium wasting diuretics like loop diuretics

Potassium sparing diuretics are also used (triamterene); other meds that interfere with RAAS include spironolactone, ACE, ARB, etc. may need adjusing

Question 8

How does acid/base status change in CKD?

Answer 8

Initially (GFR ~40), a NAGMA/hyperchloremic metabolic acidosis — related to reduced ammonia production

As renal function worsens (GFR ~15-20), becomes HAGMA d/t retained organic acids/failure to excrete anions

Presence of acidosis can induce protein catabolic state

Question 9

______ is a syndrome caused by accumulation of multiple toxins in CKD as well as loss of fluid/electrolyte homeostasis, hormone regulation, and progressive increase in systemic inflammation affecting bone, blood, skin, heart, nervous system, GI system, etc.

Answer 9

Uremia

Question 10

Characteristic changes with CKD include:

_____phosphatemia

_____calcemia

______vitaminosis D

The above 3 result in secondary _____parathyroidism

Answer 10

Hyperphosphatemia
Hypocalcemia
Hypovitaminosis D

Hyperparathyroidism

[hyperparathyroid symptoms include fatigue, malaise, muscle weakness]

Question 11

Changes in bone metabolism (due to hyperparathyroidism induced by hyperphosphatemia, hypocalcemia, and hypovitaminosis D) with CKD lead to what abnormalities?

Answer 11

Osteitis fibrosa cystica (high turn-over bone disease causing cysts to form in bones)

Osteomalacia (defective mineralization)

Adynamic bone disease (decreased rate of bone turnover without mineralization defect; worse in DM)

Question 12

PTH effects on cardiovascular system and potential tx

Answer 12

Elevated PTH —> cardiac muscle fibrosis

Increased vascular calcification and atherosclerosis

Tx includes supplemental calcitriol (vit D analog) to suppress PTH

Question 13

Number one cause of mortality in pts with CKD

Answer 13

Cardiovascular disease

[likely associated with increased inflammatory state with cytokines and CRP]

Requires aggressive interventions including BP management, lipid management, exercise, smoking cessation, weight reduction, etc.

Question 14

What causes the anemia associated with CKD?

What kind of anemia is it?

Answer 14

Decreased erythropoietin production

Normochromic, normocytic anemia with associated neocytolysis (premature RBC death)

Question 15

Signs/symptoms of anemia associated with CKD

Answer 15

Fatigue, decreased exercise tolerance

Decreased cognition and mental acuity

Impaired host defense against infection

Left ventricular hypertrophy (LVH) — d/t chronic low O2 delivery activating SNS to increase HR and SV

Question 16

Neuromuscular effects are seen by stage ____ of CKD and include WHAT signs/symptoms?

Answer 16

STAGE 3

Neuromuscular irritability = twitches, hiccups, cramps

Peripheral neuropathy by stage 4 — sensory predominates until later stages, LE > UE

Question 17

GI effects of uremia

Answer 17

Uremic fetor — urine-like breath odor associated with unpleasant metallic taste

Gastritis, peptic disease and mucosal ulcerations

Anorexia, N/V

Constipation

[pts also become calorie depleted d/t new dietary restrictions including sodium, potassium, etc]

Question 18

Endocrine effects of CKD include increased plasma levels of _____ (which is usually cleared by the kidney), ______ levels of estrogen in women, and _____ levels of testosterone in men

Answer 18

Insulin; decreased; decreased

Question 19

How do endocrine effects of CKD affect young women? What about young children?

Answer 19

Young women: Fertility changes, irregular menstrual cycles

Children: growth retardation, failure to thrive

Question 20

Skin changes associated with CKD

Answer 20

Hyperpigmentation (likely d/t decreased excretion of pigments)

Pruritis — intense itching is hallmark if uremia!! Worse with hyperphosphatemia

Question 21

Tx/management of CKD

Answer 21

Control BP — ACE-I and ARBs are first line

Monitor volume status for edema (I/Os, daily weights)

Dietary changes (Na+ restriction, protein restriction but monitor for malnutrition)

Assess and tx cardiac risk factors

Monitor for extra-renal complications — anemia, GI, bone changes, etc.

Question 22

What nephrotoxic drugs must be avoided in CKD?

Answer 22

NSAIDs

Antibiotics (aminoglycosides)

Antiarrhythmics

Radiocontrast agents and gadolinium

Question 23

At what CKD stage/GFR should you refer your pt to nephrology for possible dialysis or renal transplant?

Answer 23

Nephrology referral at CKD stage 4 — when GFR is <30

[dialysis or transplant must be initiated when GFR is 15 or less]

Question 24

Describe dialysis

Answer 24

Goal is volume and toxin reduction

Solute diffusion and water transport across a selectively permeable membrane; can be intermittent (3-4 hrs, 3x/week)

Question 25

Describe peritoneal dialysis

Answer 25

Uses abdominal cavity and peritoneal membrane as filter; Some movement also occurs via lymphatics

Hyperosmolar solution (typically glucose) creates osmotic gradient

Removes low molecular weight substances — creatinine, urea, K+, as well as large molecules like albumin

With time, instilled solution equilibrates toward serum osmolality

Question 26

What are some important considerations for pts on peritoneal dialysis?

Answer 26

Variable gradients based on peritoneal membrane

Nutritional challenges: balancing protein needs, serum glucose, weight gain

Diabetics will need additional insulin!

Sclerosing encapsulating peritonitis: entraps loops of bowel —> symptoms of bowel obstruction

Peritonitis, infection at catheter site, catheter malfunction, hernias, fluid leaks

Question 27

Describe hemodialysis

Answer 27

Creation of AV fistula — joins high pressure vessel to low pressure vessel as access port

Blood removed for cleansing then returned to body; attached to heparin pump to prevent clotting

Question 28

Preparation for renal transplant involves CV and pulmonary evaluations. What are the contraindications?

Answer 28

Malignancy
Active infection
Significant cardiopulmonary disease

Question 29

With kidney transplants, the renal allograft is placed in the _____ space; its vascular supply is the _____ artery and vein; the ureter is attached through the muscular layer to approximate sphincter function

Answer 29

Extraperitoneal; iliac