2-3: Renal and Urology Flashcards
What are the three main functions of the renal system?
- excretion
- elimination
- regulation
What is the difference between excretion and elimination?
They both have to do with organic waste products, but things do no stay in the body during excretion and they do stay in the body during elimination
What types of things does the renal system regulate?
- blood volume and solute concentration
- control of the body’s water balance
- fluid and electrolyte balance
- regulation of BP
- regulation of the acid-base balance
- regulation of hematocrit
Where are the kidneys located?
on either side of the vertebral column between L1 and L3
left kidney is higher than right
What is the GFR
the glomerular filtration rate- amount of filtrate produced by the kidneys each minute
Where is creatinine produced
in the muscles
What types of things can alter the creatinine level?
- muscle mass changes
- liver disease
- malnutrition
- exercising
- renal failure
- medications
- ketoacidosis
What is the lag time of serum creatinine behind GFR?
2-3 days
what is the most common cause of elevated BUN?
poor kidney function
What is the normal value for BUN?
7-21 mg per 100 mL of blood
What does a very high BUN indicate?
moderate-to-severe renal failure
What is the most commonly used diuretic and what does it do ?
Thiazide
inhibits the sodium-chloride transporter in the distal tubule
Acute renal failure is now referred to as _____
acute renal injury (AKI)
What is azotemia?
a rise in BUN
What are the three types of acute renal failure (or AKI)
- prerenal
- intrinsic
- postrenal
How does prerenal AKI come about?
decreased blood flow to the kidney -> causes volume loss, decreased renal perfusion, and heart failure
How does intrinsic AKI come about?
there is actual tissue damage to the parenchyma
- structural injury is the hallmark of intrinsic AKI
What are some causes of intrinsic AKI?
- acute interstitial nephritis (AIN)
- acute glomerular nephritis (AGN)
- acute tubular necrosis (ATN)
- renal artery / vein insult
- hepatorenal syndrome`
How does postrenal failure come about?
mechanical obstruction of the urinary collecting system, including the renal pelvis, ureters, bladder, or urethra
What is the mnemonic for dialysis indications?
AEIOU
A- acidosis
E- electrolyte imbalance (hyper-k)
I- ingestion
O- (fluid) overload (pulm edem)
U- uremia (encephalopathy)
What is the mnemonic for dialyzable toxins?
I STUMBLE
I- isopropyl alcohol
S- salicylates
T- theophylline
U- uremia
M- methanol
B- barbituates, beta blockers
L- lithium
E- ethylene glycol
At what GFR percentage do substances such as urea and creatinine start to show significant increases?
50%
What are some emergency complications of CRF / CKD?
- pericarditis
- encephalopathy
- GI symptoms
- anorexia
- n/v/d
- hypertension
- CHF
- malnutrition
- hypoglycemia
- platelet dysfunction with tendency to bleeding
When is emergency dialysis especially beneficial for a patient with acidosis?
when the acidosis is severe (<7.2) and refractory to sodium bicarbonate (or unable to give bicarb due to fluid overload)
When is emergency dialysis especially useful for a patient with electrolyte imbalances?
in pt with hyperkalemia when potassium >6.5 or when seen with EKG changes
What is rhabdomyolysis?
breakdown of muscle fibers secondary to injury resulting in the release of their intracellular contents into the bloodstream
skeletal muscles account for __-___% of total body mass
40-50%
What components are primarily intracellular in the muscle?
- potassium (leads to hyperK if cell bursts)
- Lactic acid (leads to metabolic acidosis if cell bursts)
- Purines and myoglobin (are nephrotoxic if cell bursts)
What two things must the Na+/K+ pump have in order to function?
ATP and oxygen
Failure of the sodium potassium pump results in what?
failure of the pump allows sodium, chloride, and calcium to flood into the cells.
If the Na/K pump fails and calcium shifts into the cells, what will this cause?
hypocalcemia, calcium deposits in muscle and renal tissue
If the Na/K pump fails and sodium shifts into the cells, what will this cause?
water follows Na, which results in cell swelling and then lysis
the cell then releases its intracellular components
What is the most “important” toxin as cells break down?
potassium- and lethal hyperkalemia can occur quickly
What is the sequential sequelae of rhabdo?
- electrolyte disturbances
- hypovolemia
- hyperkalemia
- metabolic acidosis
- coagulopathy disturbances
- AKI
- multi-system organ failure
When should rhabdo be suspected when evaluating CK levels in a patient and what are CK levels usually in a rhabdo patient?
rhabdo should be suspected when the CK levels are 2-3 x greater than normal
CK values are typically 5-10x greater than normal reference ranges
What will be present in the urine in cases of rhabdo?
hemoglobin or myoglobin
urine test is only 50% sensitive, so it does not rule out rhabdo
Why do PTT, PT, and platelet count need to be evaluated in cases of rhabdo?
because DIC is possible
What is the risk of developing a UTI with an indwelling catheter?
10-30%
What is the prehospital treatment for rhabdo?
aggressive fluid resuscitation with isotonic crystalloids
administer a min of 500 ml/H bolus, then titrate to maintain a urinary output of 1.5-2 mL/kg
What is the most common association with UTIs in men under the age of 50?
STDs
____ stones account for 75% of kidney stones
calcium
20% of kidney stone patients will require hospital admission because of:
- severe pain
- inability to excrete fluid
- urinary tract infection
- inability to pass the stone
What is the most commonly used diagnostic test for kidney stones?
CT scans without contrast
How do NSAIDs work for kidney stone pain?
they inhibit the formation of prostaglandin E2, which is the mediator of renal colic pain
Patients presenting with kidney stone signs and symptoms should be examined for possible _____. Why?
AAA
the signs and symptoms of a leaking aneurysm mimic those of a kidney stone
What are the indications of a Foley catheter?
- any patient that requires monitoring of urinary output
- sedated or medically paralyzed patients
- long transports
- prevention or management of neurogenic bladder
What are the contraindications of a Foley catheter?
- urethral trauma
- multisystem injuries
- pelvic fractures
- straddle impacts
- indications of urethral trauma
- blood at the meatus of urethra
- scrotal hematoma
- high riding prostate
What should urinary output be for adults?
20-50 cc’s/hour for adults
What should you consider if the catheter is draining little or there is no urine despite adequate fluid intake
- consider the level of the drainage bag
- consider flushing the catheter
The bag should always be lower than the level of the bladder
Where in the brain is ADH released?
The posterior pituitary
In renal insufficiency, what happens to relative tubular secretion? What does this do to serum creatinine?
relative tubular secretions increase, which can falsely depress creatinine and interfere with correlation of serum creatinine with GFR
What are the three acid-base compensatory systems in the body?
- buffer
- respiratory
- renal
(in that order!!)
What are the two markers for AKI?
BUN and creatinine
