Renal Disorders Flashcards
How are glucose and insulin used to treat hyperkalemia associated with AKI?
when insulin transports glucose into cells, it carries potassium with it
Most common causes of CKD
Diabetes (35%)
High blood pressure (30%)
Glomerulonephritis (12%)
Functions of the kidney
- waste management
- drug and peptide hormone elimination
- maintenance of fluid and electrolyte balance
- regulation of acid-base balance
- endocrine functions
- regulation of extracellular fluid balance and BP
Hormones associated with kidneys
a. Renin - RAAS
b. Aldosterone - reabsorption at distal tubule
c. ADH - reabsorption at collecting tubule
d. activate vitamin D - stimulate Ca and phosphate absorption in intestine
e. erythropoietin formation - bone marrow
What goes on in the Glomerulus/Bowman’s Capsule
Filtration
- water, NaCl, glucose, amino acids, urea
What goes on in proximal convoluted tubule?
Reabsorption
- NaCl, water, urea, bicarbonate, glucose, others
What goes on in Loop of Henle?
Concentrate urin
reabsorb water (descending loop) reabsorb sodium (ascending loop) urea secretion (thin segment)
What goes on in distal convoluted tubule and collecting tubule?
distal tubule: acid-base balance
collecting tubule: electrolyte/fluid balance
How much fluid does the kidney filter per day?
180L/day
120mL/min
Causes of Pre-renal AKI
reduction in blood flow to kidney
a. hypovolemia
b. decreased CO
c. thrombo-embolic obstruction of renal vasculature
Causes of intra-renal AKI
damage to structures within kidney
a. acute tubular necrosis
b. glomerular, tubular or interstitial damage
Causes of post-renal AKI
obstruction in the urinary tract BELOW kidney
a. renal calculi (kidney stones)
b. clots in ureters/urethra
c. tumours
Kidneys receive how many percent of CO?
20-25%
Acute Tubular Necrosis (ATN)
death of tubular epithelial cells, damage to tubules
caused by nephrotoxic drugs, severe hemolytic reactions or muscle trauma
Glomerulonephritis
inflammation of the glomeruli caused by an IMMUNE RESPONSE
antigen-antibody complex trapped in glomerulus, causing large molecules to enter filtrate
Manifestations of glomerulonephritis
hematuria
proteinuria
hypertension
edema
Pyelonephritis
inflammation of kidney pelvis and parenchyma from infection
- can descend from bloodstream or ascend from UTI
- causing fibrosis formation
Manifestations of pyelonephritis
Fever abdo pain dysuria (pain when urinating) cloudy urine polyuria/urgency urinary odour
Nephrotic syndrome
urinary excretion of >3g of protein/day, edema, hypoalbuminemia
(SEVERE)
Nephritic syndrome
nephron inflammation characterized by hematuria and RBC casts, SOME proteinuria and edema
- less severe as nephrotic
Manifestations of Nephrotic syndrome
edema (face, eyes, leg, ankle)
foamy urine (protein)
weight gain
Azotemia
nephrotoxicity that involves excess nitrogen compounds (urea, creatinine, nitrogen-rich compounds)
- elevated BUN and creatinine
- uremic frost
can occur in all types of AKI
Uremia
high levels of urea in blood
(more severe than azotemia)
TERMINAL clinical manifestation of kidney failure
CrCl <10-20mL/min
Acute uremic symptoms
- fluid/electrolyte balance dysregulation
- increase metabolic wastes (metabolic acidosis)
- uremic waste affecting GI tract
- decreased platelet adhesiveness and immune response
- metabolic waste on skin
- decreased EPO secretion (anemia)
AKI management
a. Discontinue all nephrotoxic agents when possible
b. Ensure volume status and perfusion pressure (plasma expanders or diuretics)
c. Consider functional hemodynamic monitoring
d. Monitor serum creatinine and urine output
e. Avoid hyperglycemia
f. dialysis (if none else works)
CKD Management
a. Management of protein intake
b. Supplemental vitamin D
c. Maintenance of sodium and fluid
d. Restriction of potassium (prevent hyperkalemia)
e. Maintenance of adequate caloric intake
f. Management of dyslipidemias
e. Erythropoietin as needed
f. ACE inhibitors or receptor blockers
g. Dialysis
h. Renal transplantation
Increase in the following is usually indicative of kidney disease
- BUN
- serum creatinine
- serum potassium
Decrease in the following is usually indicative of kidney disease
- GFR
- creatinine clearance
- drug excretion
Sudden causes of uremia
trauma, shock, toxins, acute glomerulonephritis, sepsis
What components are needed to calculate CrCl using Cockroft Gault?
age
BW in kg
SCr in μmol/L
What causes hyperkalemia in kidney disease?
a. kidney dysfunction causing inability to excrete K+
b. K+ move out of cells (metabolic acidosis)
c. ACEIs
d. excessive K+ intake
Sever hyperkalemia
K+ >= 7.0mmol/L
K+ = 6.0-6.9mmol/L with ECG changes
What is the most appropriate treatment when hyperkalemia is accompanied by ECG changes?
calcium gluconate to stablize cardiac membrane
Interventions to shift K+ into cells
a. insulin plus glucose (most effective! rapid acting)
b. sodium bicarbonate
c. inhaled salbutamol
Interventions to remove K+ from body
a. sodium polystyrene - binds K+ in gut to increase GI excretion
b. hemodialysis
c. diuresis
4 Key Therapeutic Strategies in management of diabetes and CKD
- manage hyperlipidemia
- control HTN
- maintain optimal glycemic control
- minimize proteinuria
Causes of malnutrition in CKD
- decreased oral intake
- protein/vitamin loss from dialysis
- low serum albumin
What drugs should be used to manage HTN in CKD?
ACEIs, ARBs, CCBs
Loop diuretics when CrCl <25ml/min
What intervention is used to treat anemia in CKD?
blood transfusion
erythropoiesis stimulating agents
possibly iron supplements
What is the target Hgb when administering ESA for anemia? What is the concern?
Hgb: 100-110 g/L
above target could increase risk of CV event
What causes hypocalcemia in kidney disease?
a. increased phosphate bind to calcium causing calcium decrease
b. decreased activation of vit D causing decreased calcium absorption
c. decreased calcium stimulates PTH secretion (causing body to take calcium from bone)
pharmacokinetic alterations in renal impairment
- decreased absorption
- decreased blood levels
- increased free fraction (protein binding)
- increased drug half life
Drug dosing adjustment is based on
- creatinine clearance
- if >50% of drug is renally eliminated
