Renal Pathology, Diuretics, and Anesthesia Flashcards
Two major pathways of natriuretic peptide
- vasodilator effects 2. renal effects that leads to natriuresis and diuresis
Natriuretic peptide is involved in the long-term regulation of _____ and _____ balance, blood volume and arterial pressure.
sodium and water
Natriuretic peptides directly dilate veins resulting in increased ______ ________ and thereby decrese _____, which reduces cardiac output by decreased _________ preload.
venous compliance / CVP / ventricular
Natriuretic peptides also dilate _______, which decreases ____ and systemic ________ pressure
arteries / SVR / arterial
NP affect the kidneys by ________ GFR and filtration fraction, which produces _________ (increased sodium excretion) and _________
increasing / natriuresis / diuresis
A second renal reaction of NPs is that they decrease _____ release, thereby decreasing circulating ________ and _______. This leads to further NATRIURESIS and DIURESIS. Decreased Angiotensin II also contributes to systemic _______ and decreased _____
renin / angiontensin II / Aldosterone / vasodilation / SVR
Natriuretic Peptides serve as a
counter-regulatory system for the renin-angiotensin-aldosterone system
ANP is produced by
atrial myocytes
ANP functions
relax smooth muscle AND promote NaCl and water EXCRETION by kdiney
Stimuli for ANP release
atrial stretch
Elevated levels of ANP are found during _________ states, such as occurs in heart failure
hypervolemic
ANP inhibits ______ release
renin
ANP increases GFR via vasodilation of the ________ arteriole and constriction of the _________ arteriole
afferent / efferent
ANP acts directly on the ______ ______ to decrease NaCl reabsorption
collecting duct
BNP is synthesized largely by the _____ as well as the brain where it was first identified
ventricles
BNP is first synthesized as prepro-BNP and then _______ twice to beecome BNP
cleaved
Natriuetic peptides are involved in the ____ term regulation of _____ and _____ balance, blood volume and arterial pressure
long / sodium and water
Cardiovascular an renal actions of NPs
natriuresis and diuresis, improve GFR and filtration fraction, inhibit renin release (decreases circulating Angiotensin II and Aldosterone), systemic vasodilation, arterial hypotension, redcued venous pressure, reduced PCWP
A substance that increases the rate of urine volume output
diuretic
Most clinically used diuretics act by decreasing the rate of ________ _________ from the tubules which causes sodium output to increase (natriuresis) which results in ________ (water output)
sodium reabsoprtion / diuresis
Common clinical use of diuretics is to decrease ___ volume and thus treat edema, CHF, or hyptertension
ECF
Although many diurectics work within minutes to effect decreases over the next few days with _____ use
chronic
What effects eventually override the effects of diuretics?
Decrease in ECF leads to decrease in MAP and decrease in GFR which eventually leads to Renin release
Review and draw slide 11
diuretics
Sometimes a combination of two diuretics is given because one nephron segment can ________ for altered sodium reabsorption at another nephron segment
compensage
Examples of osmotic diuretics
urea, mannitol
Osmotic diuretics, if injected into the bloodstream are filtered and FILTERED and not easily ________, thus they draw fluid into the ________
reabsorbed / tubules
Glucose can act as a _______ diuretic in diabetics who spill glucose in their urine resulting in increased urine output
osmotic
How do loop diuretics work?
they inhibit the Na-2Cl-K co-transporter in the TAL of Henle’s loop
With loop diuretics, there is inc reased delivery of solutes to the _______ tubule due to inhibited reabsoption, these solutes act as ______ agents to draw fluid into the tubule
distal / osmotic
With loop diuretics, this transporter normally reabsorbs 25% of the sodium load. However, the countercurrent multiplier system is disrupted and the interstitium cannot become ________
hyperosmolar
Loop diuretics also induce renal synthesis of _________, which contribute to their renal action including increase in renal blood flow and redistribution of renal cortical blood flow
prostaglandins
_________ are the most commonly used diuretics
thiazide
Thiazide diuretics work by inhibiting sodium chloride reabsorption in the ____ ______ _____
EARLY DISTAL TUBULE
Normally, the transported mechanism only absorbs ___% of filtered sodium in the distal tubule
5%
Are Thiazide diuretics more or less efficacious than loop diuretics in producing diuresis and natriuresis?
LESS
Loop and thiazide diuretics increase sodium delivery to the distal segment of the distal tubule, this increases potassium loss and potentially causes ________
hypokalemia
Carbonic Anyhydrase Inhibitors like _________ reduce reabsorption of Na+ in the ______ by decreasing _______ reabsorption
acetazolamide / PCT / bicarbonate
In the PCT, bicarbonate reabsorption is coupled to ______ reabsorption via Na+-H+ counter-transport
Na+
Aldosterone antagonists like _________ are also _______ sparing diuretics
Spironolactone / potassium
Aldosterone antagonists decreases reabsorption of ____ and decreases ___ secretion by competing for ______ binding sites in the distal segment of the DISTAL TUBULE
Na / K / Aldosterone
Aldosterone antagonists are often used in conjunction with ____ or ____ diuretics to help prevent HYPOKALEMIA
thiazide or loop
Na+ channel blockers like _____ and ______ decrease Na/K-ATPase in the ____ ______ and thereby decrease Na+ reabsorption. These diuretics also _____ potassium
amiloride / triamterene / collecting tubules / spare
Review slide 20
CLASS / MOA / Tubular site of Action
AKI
abrupt loss of kidney function within a few days, severe acute kidney injury where the kidneys may abruptly stop working entirely or almost entirely, patients with AKI may eventually RECOVER normal kidney function
CKD
An irreversible decrease in the number of functional nephrons
______ ______ is the leading cause of ESRD followed by _________
diabetes mellitus / HTN
Reflects an abnormality originating outside the kidney. Kidneys not getting enough blood flow and therefore becomes ischemic. Examples are heart failure and hypovolemia. What catefory of Acute renal failure is this?
Pre-renal AKI
Damage to the kidney itself. Examples include toxins, infections, autoimmune disease and direct renal injury. What category of Acute Renal Failure is this?
Infra-renal AKI
Obstruction of the collecting system anywhere from the calyces to the outflow of the bladder. Examples include stones, urethral valves, tied off ureter and kinked foley. What classification of Acute Renal Failure is this?
Postrenal AKI
With CKD, symptoms often do not occur until the number of functioning nephrons decreases to at ___% below normal
70%
CKD is usually defined as the presence of kidney damage or decreased kidney function that persists for at least ____ months
3 months
With CKD, relatively normal blood concentrations of most electrolytes and normal body fluid volumes can still be maintained until the number of functioning nephrons decreases below __ to ___% of normal
20 to 25
______ is the term to describe a clinical syndrome characterized by renal dysfunction that would prove fatal without renal replacement therapy
ESRD
ESRD GFR %
<25% of normal
CRI GFR%
25-40% of normal GFR
Decreased renal reserve GFR%
60-75% of normal GFR
Patients with decreased renal reserve are often ______ and frequently do not have elevated blood levels of creatinine or urea.
asymptomatic
Established renal insufficiency results in abnormal serum creatinine and BUN values but ________ may be the only symptom (due to reduced concentrating ability)
nocturia
Injury to renal vasculature can be due to _________ of large vessels, _________ dysplasia, and __________ which refers to sclerotic lesions of smaller arteris, arterioles and golmeruli
atherosclerosis / fibromuscular / neprhosclerosis
Glomerulonephritis is most commonly caused by deposition of _____-______ complexes in glomerular membranes
antigen-antibody
Glomerulonephritis can be post _________ infection and ________ can cause this as well
streptococcal / lupus
Atherosclerotic or hyperplastic lesions of the large arteries frequently affect one kidney more than the other and, therefore cause _________ diminshed kidney function
unilaterally
Benign _________ is th most common form of kidney disease. When sclerosis occurs in the glomeruli, the injury is referred to as ________
nephrosclerosis / glomerulosclerosis
_________ __________ is when the bladder wall fails to coolude the ureter during micturation and contaminated urine from the lower urinary tract is propelled retrograde into the kidney and can result in an INFECTION
Vesicoureteral reflux
_____ _______ is a condition where large amounts of protein are lost in the urine due to destruction of or loss of negative charge on the capillary basement membrane in the glomerulus
nephrotic syndrome
Pyleoneprhritis review
most common organism is E.coli, begins in renal medulla and affects it more than cortex, since countercurrent mechanism is in medulla they often have difficulty concentrating urine
______ is the effect of renal failure on the body
uremia
______ ____ is a constellation of signs and symptoms of anorexia, N/V, pruritis, anemia, fatigue, coagulopathy that reflects the kidney’s progressibe inability to perform its excretory, secretory and regulatory functions
uremic syndrome
The most important RISK FACTOR for ESRD is _________ being that it is a major cause of both diabetes and hypertension
obesity
Renal failure and ESRD
prone to pulmonary edema and fluid overload, minute ventilation is increased to compensate for acidosis, osteomalacia
Osteomalacia
Vit D is convereted in two steps (1st in liver and then in kidneys) before it can promote Ca++ absoroption from the intestine. Thus decreases in the active form of virtamin D are seen. Also the rise in phosphate concentration stimulates PTH which causes skeletal muscle demineralization (secondary hyperparathyroidism)
More effects of renal failure (review)
abnormal glucose tolerance, platelet and WBC dysfunction, hypersecretion of gastric acid increases risk of ulcers, autonomic neuropathy can slow gastric emptying, peripheral neuropathy is common
Kidney lesions which decrease ____ and ______ excretion promote _______
sodium / water / hypertension
If one kidney or part of one is ischemic or damaged the normal kidney gets _________ because renin and angiontensin II from the ischemic kidney affect the normal kidney and drives up BP
punished
The ischemic renal tissue secretes large quantities of ____
renin
Effective treatment of hypertension related to kidney disease requires enhancing the kidney’s capability to excrete ______ and ______. This is accomplished by increasing _____ or by decreasing _____ ______.
salt and water / GFR / tubular reabsorption
With dialysis, the artifical kidney passes blood across a thin membrane, on the other side of the membrane is a dialyzing fluid where undesired substances pass by ________
diffusion
With dialysis, the rate of movement of solute across the membrane depends oon the _____ _____ of the solute and the permeability and surface area of the membrane and also the length of time the blood and fluid remain in contact with the membrane
concentration gradient
With dialysis, the maximum rate of solute transfer occurs initially when the concentration gradient is _________ (when dialysis begins)
greatest
How much blood is usually in the dialysis machine at any time?
500 cc
Is there phosphate, urea, urate, sulfate or creatinine in the dialyzing fluid?
NO
Indications for dialysis
fluid overload, hyperakalemia, severe acidosis, metabolic encephalopathy, pericarditis, coagulopathy, refractory GI symptoms, drug toxicity
BUN normal is
10-20 mg/dL
Ammonia is converted to urea in the ____ and urea is handled by the ______
liver / kidney
___ to ___% of urea is passively reabsorbed in the nephron, _________ wiill increase this
40-50% / hypovolemia
Increased BUN can be from decreased ______ or increased _______ breakdown
GFR / protein
Patients on hemodialysis should undergo dialysis during the ____ hrs preceding elective surgery
24 hrs
normal creatinine in men
0.8 to 1.3
Normal creatinine in women
0.6-1
Creatinine concentration is directly related to _____ _____ mass and inversely related to _____
body muscle / GFR
_______ ________ is a way to measure GFR
creatinine clearance
GFR _______ with age in most people.
decreases (5% decline per decade after age 20)
Creatinine clearance formula
140-Age x IBW / 72 x creatinine **multiply CC by 0.85 for women
BUN / creatinine rationis > 10:1 are seen in ____ _______ or conditions associated with decreased tubular flow and obstructive uropathy
volume contraction
urinary pH is helpful when arterial pH is known. Urinary pH > 7.0 in the presence of systemic acidosis is suggestive of renal _____ _____
tubular necrosis
Specific gravity is related to _______ osmolality
urinary
A low specific gravity in the face of plasma hyperosmolality is consistent with _____ _____
diabetes insipidus
Patients with renal disease are more susceptible barbiturates because or decreased ____ ______
protein binding
Propofol, ketamine and etomidate have no significant differences in _____ patients
uremic
Extra caution with ______ since active metabolites can accumulate
diazepam
Dexmedetomidine is primarily metabolized in the ______. Renal impairment may cause longer lasting effects related to less ______ ______
liver / protein binding
T/ F Significant renal impairment may affect the disposition, metabolism, and excretion of the commonly used anesthetic agents
TRUE
Opiod cautions with renal failure
morphine, demerol and hydromorphone BAD. Use fentanyl
Succinylcholine is safe in patients with K <5.0 but will transiently increase K+ by almost ___mEq/L
0.5
Drug of choice is ______ for renal failure
cisatracurium
_____ ______ are the most likely foup of drugs used in anesthetic practice to produce prolonged effects in ESRD because of their dependence on renal excretion
muscle relaxants
Muscle relaxants to avoid that depend primarily on renal excretion
pancuronium, pipecuronium, alcuronium, doxacurium
With ESRD, elective surgery should be below ____mEq/L. If it is not, we generally dialyze the patient for a minumum of ___ hrs
5.5 / 2
T/F peritoneal dialysis is generrally performed until just prior to the procedure and the dialysate should be drained prior to the procedure
TRUE
What fluids do you want to avoid with ESRD and why?
LR because of the potassium
_____ ______ may be the best as it will decrease the risk of respiratory acidosis which is not good in the setting of metabolic acidosis
controlled ventilation
Algorithm on slide 55
anesthesia for the dialysis patient
For patients with mild to moderate renal impairment, _______ is a key facator in the causation of periop renal failure.
hypovolemia
post-op renal failure has a mortality of ____%
50%
Prophylaxis for patients with mild to moderate renal failure may be
mannitol 0.5g/kg
Risk factors for perioperative renal failure
sepsis, hypovolemia, obstructive jaundice, aminoglycoside antibiotics, NSAIDS, ACE inhibitors, recent dye injections
Rational management of intraoperative oliguria
First make sure foley is patent, assess fluid status, admin bolus if needed and observe, check CVP, increase BP if it is low, if patient is on lasix they may need their daily dose, consider mannitol
Most common composition of renal stones
calcium oxalate
Who is more likely to get a kidney stone
men
Most stones <4mm pass _______
spontaneously
Alpha blockers like _____ may help decrease tone of ureter and promote passage of stone
terazosin
May have surgical mangement of larger stone or if stone has not passed in ___ days
30
ESWL is used for disintegration of stones in the kidney or ureter above the level of the ____ ____
iliac crest
Contraindiciations to ESWL
inability to properly position patient, pregnancy, infection, obstruction below the level of the stone, proximity of prosthetic device
With ESWL shocks are timed for 20 ms after the ___ wave so it is deliverd during the ventricular _____ _____
R / ventriular refractory
Stone prevention
drink water, avoid cola beverages, limit protein, nitrogen and sodium in diet
With Gout, 75% of first attacks involve the ___ ____. Serum urate is not always ________.
big toe / urate
Gout is more common where there is a diet rich in _____, _____ and _____
protein / fat / alcohol
GOUT pain relief involves NSAIDs (first line) and _________ which works by alkalinizing the urine which traps weak acids
acetazolamide
Gout prevention
allopurinol (watch out fatal interacction with azathioprine which is a transplant drug can be fatal), uricocurics, caffeine, CPAP
