Adult Renal Flashcards
How do you assess the patency of a arteriovenous (AV) graft in the forearm ?
auscultate the site for a bruit
What are the functions of the kidney ?
- regulate the volume and composition of extracellular fluid
- excrete waste
- control BP
- produce erythropoietin (building block of RBCs, decreased kidney function can lead to anemia)
- activate vitamin D (important to absorb calcium)
- regulate acid-base balance
What is Azotemia ?
loss of renal function/ increase of metabolic waste products
- aka buildup of waste products
What is Oliguria ?
decrease in urinary output
- < 400 mL/day
How suddenly does acute renal failure (injury) occur ?
develops over hours/days
- with elevation of BUN & serum Creatinine
What will the lab values in acute renal failure look like ?
- decreased glomerular filtration rate
- increased serum creatinine
- increased creatinine clearance (24 hr urine)
- increased BUN
What is the best indicator of renal failure ?
serum creatinine
- represents how much irreversible damage has already occured
What lab value do we use to diagnose chronic kidney disease/ implementation of dialysis ?
glomerular filtration rate
What is the best indicator of renal function ?
creatinine clearance (24 hr urine)
- represents the degree of seriousness and how well the kidneys are functioning
What does the BUN measure ?
the amount of urea nitrogen in the blood
- represents an indirect measurement of renal function and the GFR
What is the best indicator for fluid balance ?
daily weights
What does Prerenal causes of acute renal failure mean ?
factors that reduce the systemic circulation/perfusion
- heart and blood vessels
- anything that causes decreased perfusion of kidneys and blood flow
- causing reduction in renal blood flow and leading to hypotension/hypovolema
- Ex.) severe blood loss, low BP, sepsis, injury, dehydration,
What does Intrarenal causes of acute renal failure mean ?
conditions that cause direct damage to the renal tissue
- kidney
- resulting in impaired nephron function and tubular necrosis
- problem with the kidney itself
- Ex.) med toxicity ischemia, prolonged dehydration/sepsis, nephrotoxic meds (NSAIDS, metformin, vancomycin)
What does Postrenal causes of acute kidney failure mean ?
causes involve mechanical obstruction of urinary outflow
- ureters and bladder
- some blockage or injury to downstream flow of kidney
- body detects that the urine isn’t going down so the kidneys will just stop producing that waste
- Ex.) prostatic hypertrophy (enlarged prostate which is very common in older men
What are the 4 phases of Acute Renal Injury (ARI) ?
- initiating (whatever caused the injury)
- oliguric (kidneys have no perfusion so they stop/decrease urine production until there is enough perfusion)
- diuretic (tx which is giving fluids or maybe diuretic so kidneys start working again)
- recovery (can be months and its when the kidneys and labs stabilize)
How long does the oliguric phase last of ARI ?
1-7 days
What are some characteristics of the Oliguric phase of ARI ?
- <400 mL/day of urine
- metabolic acidosis (kidneys can’t excrete acid products of metabolism)
- hyperkalemia (kidneys can’t excrete potassium) and hyponatremia
- increased BUN and creatinine
- hematologic disorders (anemia)
- fatigue and malaise (sick feeling)
What are some characteristics of the Diuretic phase of ARI ?
- gradual increase in urine output (1-3 L/day to 3-5 L/day)
- hypovolemia, dehydration
- hypotension
- nephrons are still not fully functioning
- uremia may still be severe, as seen in labs (may look bad for about a few days but should get better gradually)
- BUN and creatinine begins to normalize
- persistent S&S
What are some characteristics of the Recovery phase of ARI ?
- begins when GFR increases
- BUN and creatinine levels plateau (even out) and then decrease
- renal function can take up to 12 months to stabilize
What causes the hyponatremia in the oliguric phase of ARI ?
the damaged tubules can’t conserve sodium
- if left uncontrolled or water excess then it can lead to cerebral edema
Why are hematologic disorders associated with ARI ?
impaired erythropoietin production and platelet abnormalities leading to bleeding
Why may a pt have low serum Ca+ in the oliguric phase of ARI ?
inability of the kidneys to activate Vitamin D
- may be on Ca+/Vita. D supplement
- when hypocalcemia occurs the parathyroid secretes PTH which stimulates bone demineralization which releases Ca+ from the bones
Why may a pt have elevated serum Phosphate levels in the oliguric phase of ARI ?
phosphate is also released when the parathyroid secretes PTH
- pt may be on phosphate binders
How long does the diuretic phase of ARI last ?
1-3 weeks
How long does the recovery phase of ARI last ?
3-12 months
What are some indications for Renal Replacement Therapy/Dialysis ?
- volume overload
- elevated serum Potassium level
- metabolic acidosis
- BUN level >120 mg/dL (43 mmol/L)
- significant change in mental status
- pericarditis, pericardial effusion, or cardiac tamponade
- clinical status of patient
Why may someone in the recovery phase of AKI need therapy or counseling ?
it’s because this phase takes 3-12 months so it can be mentally draining and can cause financial hardships
- also if your kidneys never recover you will need dialysis which is a significant lifestyle change
What is a common cause of AKI ?
acute tubular necrosis
What is a common cause of CKD ?
diabetic nephropathy
How much urine should you excrete per hour ?
80 mL per hr
What is Chronic Kidney Disease (CKD) ?
progressive, irreversible loss of kidney function
What is the main diagnostic value when wanting to diagnose CKD ?
Glomerular Filtration Rate (GFR)
What are the leading causes of CKD ?
- diabetes (50%)
- HTN (25%)
Can Vancomycin cause Nephrotoxicity ?
yes because if you have impaired kidneys, it can cause delayed and decreased elimination which can lead to accumulation of drugs and the potential for drug toxicity
- doses and frequency have to be adjusted according to severity of kidney disease
Why does pruritus happen in CKD ?
the buildup of urea causes the itchiness
When on dialysis, do all patients still produce urine ?
after being on dialysis for a while it’s not uncommon for the pt’s to develop anuria/no urine output
What are some S&S of CKD ?
- uremia
- oliguria (as CKD worsens) & anuria
- metabolic acidosis (breathe may have uric scent to it because they are trying to breathe it off)
- anemia
- infection
- respiratory system
- pleural effusion
- predisposition to respiratory infection
- dyspnea
- pulmonary edema