Part 29 Flashcards
Diuretics function and major applications (2)
Increase output of urine
- treat hypertesnion
- mobilize edematous fluid
Diuretics mechanism of action
Blockage of Na+ and Cl- reabsorption, which prevents the passive reabsorption of water and causing water and solutes to be retained in the nephron promoting their excretion
Drugs whose site of action is early in the nephron have….
As a result they…
…opportunity to block greatest amount of solute reabsorption, produce greatest amount of diuresis
Loop diuretics work at the…
They are the most…
…ascending loop of henle, the most effective diuretics available
K+ sparing diuretics work at the…
They are very ___ diuretics because they don’t cause much ____, but can be helpful to reduce ____
…distal convoluted tuble and collecting duct
weak, diuresis, hypokalemia
Furosemide (Lasix) mech of action, where is it excreted?
acts at thick ascending limb of loop of henle blocking reabsorption of Na+ and Cl-, preventing passive reabsorption of water
The liver excretes it
Loop diuretics have activity even during…
…renal failure
Furosemide (Lasix) length of action for oral and IV
Oral - diuresis lasts 8 hours after 1 hour absorption
IV, diuresis lasts for 2 hours within minutes
Furosemide (Lasix) therapeutic uses (3)
- reserved for rapid mobilization of fluid such as pulmonary edema with congestive heart failure
- uncontrolled hypertension
- Electrolyte imbalances
Furosemide (Lasix) ADR’s (7)
- Dehydration
- Thrombosis or embolism
- hypotension
- ototoxicity
- hyperglycemia
- hyperuremia (gouty attack)
- hyperlipidemia
Furosemide (Lasix) can be administered ___ to minimize unfavorable effects
Intermittent schedule
Furosemide (Lasix) drug interactions (3)
- Digoxin effects can be potentiated by loss of K+
- used in combo with aminoglycoside can increase hearing damage
- K+ sparing diuretics can counterbalance K+ wasting effects therby reducing risks of hypokalemia
Furosemide (Lasix) dosage oral, why is taking it in morning important
20 to 80mg/day single dose, administration at night will result in urination all night long
Hydrochlorothiazide (hydrouracil) drug class, mehc of action
Thiazide diuretic,
Blocks reabsoroption of sodium and chloride in early segment of distal convoluted tuble
Hydrochlorothiazide (hydrouracil) requires ___ to function, unlike ____
Adequate GFR, loop diuretics which can promote fluid loss with significant renal impairment
Hydrochlorothiazide (hydrouracil) indications (what is it the DOC for?) (4)
- HTN
- Edema
- diabetes insipidus
Hydrochlorothiazide (hydrouracil) ADR’s (4)
- hypokalemia
- hyperglycmia
- hyperlipidemia
- produces fetal harm and shouldn’t be used during pregnancy
Spironolactone (aldactone) mech of action, drug class
Blocks action of aldosterone at distal tubule, retention of K+and increased excretion of Na+,
K+ sparing diuretic
Spironolactone (aldactone) may take up to ___ to exert effects
48 hrs
Spironolactone (aldactone) indications (5)
- hypertension
- edema
- hepatic cirrhosis
- heart failure
- primary aldosteronism
Spironolactone (aldactone) ADR’s (2)
- hyperkalemia (never combine with K+ supplements or other K+ diuretics
- endocrine effects similar to other steroid hormones
Elperenone (Inspra) vs Spironolactone (aldactone)
Acts like spironolactone, K+ sparing diuretic but has lower affinity for andorgen receptors removing endocrine effects
Elperenone (Inspra) ADR
hyperkalemia
Triamterene (dyrenium) mech of action, drug class
Dirsupts Na/K ATPase exchange in distal nephron, a direct inhibitor acting very quickly but only producing minimal diuresis
-K+ sparing diuretic
Triamterene (dyrenium) therapeutic uses (2)
-used alone or incombo to treat hypertension and edema
Osmotic diuretic compound used in medicine
-mannitol
Mannitol (osmitrol) mech of action and drug class
- pharmacologically inert
- creates osmotic force within lumen of nephron,
Osmotic diuretic
Mannitol (osmitrol) administration
IV injection
Mannitol (osmitrol) therapuetic uses (3)
- prophylaxis of renal failure
- reduciton of inracranial pressure
- reducjtion intraocular pressure
Mannitol (osmitrol) ADR’s (2)
- can precipiptate congestive heart failure
- edema by pulling water into interstitial spaces
Carbonic anhydrase inhibitors (acetazolamide (diamox)) function
Sulfonamide without antibacterial activity, primarily used for other pharmacologic actions such as treatment of glaucoma rather than diuretic effect because much less effacious than thiazides or loop diuretics
acetazolamide (diamox)) mehc of action
- Inhibitss carbonic anhydrase located intracelluarly on apical membrane of proximal convoluted tubular epithelium
- HCO3- is retained in lumen resulting in marked elevation of urinary pH - loss of HCO3- causes hyperchloremic metabolic acidosis and decreased diuretic efficacy after several days of therapy
acetazolamide (diamox) therapeutic uses (3)
- Glaucoma
- mountain sickness
- edema rarely used
acetazolamide (diamox) ADR’s (4)
- metabolic acidosis
- hypokalemia
- renal stone formation
- drowsiness and parasthesias
(T/F) Loop diuretics can be used with caution in pregnancy
true
Hydrochlorothiazide (hydrouracil) drug interactions (3)
- digoxin
- antihypertensive drugs
- lithium
Even though albumin is a small enough protein to pass thru the fenestrations of the renal corpuscle, it doesn’t because….
Why is maintaining protein in plasma important?
….albumin is negatively charged as well as the filter so it repels it back into the circulation
It helps maintain oncotic pressure
Albumin (protein) in urine tested on disptick is a sign of…
…nephrotic syndrome
Afferent arterioels are branches of the ____ arteries and each supply a single ____
interlobular, glomerulus
Efferent arterioles divide to form the ___
Peritubular microcirculation
Why should you avoid NSAIDS and ASA with vomiting and diarrhea?
These irreversibly block prostaglandins in the endothelium, preventing their release to act as dilators of the afferent arterioles that need to dilate to increase GFR
Factors that impact afferent or efferent arteriole tone (5)
- angiotensin II
- ADH/vasopressin
- prostaglandins
- Endothelins
- Epi/norepi
Endothelin definition
Proteins that constrict blood vessels and raise pressure, kept in balance by other mechanisms but when over-expressed contribute to hypertension
In order to compensate for lowered GFR pressure, we will vaso___ the afferent and vaso___ the efferent arteries
dilate, constrict
Sympathetic innervation of the bladder vs parasympathetic innervation of the bladder
Sympathetic allows for smooth muscle contraction of the bladder, parasympathetic allows for relaxing of internal urethral sphincter
With one kidney removed, blood flow in the remaining kidney will…
…compensate quite well nearly double within a few weeks
Increase hydrostatic pressure in Bowman’s capsule, often due to urethral obstruction, can cause…
…edema of the kidney
Urine volume is a poor indicator of _____
Renal dysfunction
Low urine output may be one of 3 categories
prerenal - the blood before the kidney
intrarenal - within the kidney
postrenal - in the ureters, bladder, or urethra
Polyuria, oliguria, and anuria values in mL/day
poly - >2L
oligo - <500mL
an - 0-100mL
A CBC is beneficial in evaluation of renal function for these 2 reasons
1) checks erythropoietin function
2) checks infection of kidney
The main organ responsible for balancing electroyltes in the body
kidney
Renal threshold
The amount of glucose (190-220mg/dL) of glucose that will result in sugar in the urine
BUN definition
Blood urea nitrogen, waste product of nitrogenous breakdown such as muscle in the body, useful measure in assessing kidney function
Creatinine definition
Breakdown of product of muscle in the body, useful measure in assessing kidney function
4 intrarenal disease possibilities
1) acute tubular necrosis
2) glomerular
3) vascular
4) tubulointerstitial
In a young patient (20’s) with hypertension, need to see if possible pathology source is…
…renal artery stenosis
3 common presentations of renal dysfunction
- hematuria
- proteinuria
- azotemia
Azotemia definition
Increased plasma conc. of BUN in bloodstream, without symptoms
Uremia definition
Toxic effects felt as wastes accumulate in the body resulting from renal failure, sometimes being excreted thru the skin, typically causese elevated BUN and creatinine
What kills from renal failure?
-hyperkalemia causing arrhythmia of heart and eventual death
BUN normal value range
Between 10-20mg/dL at all times
What are 4 things that can decrease BUN?
- Overhydration
- liver failure
- neg nitrogen balance
- pregnancy
Normal creatinine level and elevated BUN level indicates a ___renal disease
Pre
BUN/Creatinine ratio
A useful measurement to determine the type of renal disease present
Creatinine is a direct reflection of ____ because it is always ____
Renal filtration rate, filtered
Only __renal disorders will affect creatinine levels
Intra
Rhabdomyolysis definition
An emergency disease that if left untreated leads to kidney failure, indicated by presence of myoglobin in urine, muscle pain, and weakness.
4 causes of elevated creatinine
- rhabdomyolysis
- acromegaly
- myesthenia gravis
- muscular dystrophy
Ceatinine clearance definition
A test that helps determine if kidneys are functioning normally by gauging the amount of creatinine in the urine compared to that in the blood
Serum creatinine concentration is the most common way to estimate ___, what is its relationship to that value?
GFR, the change in serum creatinine is inversely related logarithmically (i.e. creatinine from 1 to 2 is GFR 1 to .5)
24 hr urine collection definition, what are some issues with it?
Gold standard test for measuring kidney function, involves having patient pee first thing in morning and then collect every following urination up until completing first pee the next morning, patient compliance is the biggest issue with it
Inulin clearance definition and function
A lab test using a compound called inulin that is only filtered by kidney, and is therefore a 100% accurate test of GFR, no longer done anymore
Healthy individuals without chronic illness can have unlimited ___ intake because it doesn’t have comorbidity associated with it. In theory, intake of this should equal ___ of it
Salt, excretion
Fractional excretion of Na+ in urine is extremely useful in distinguishing the most 2 common causes of acute kidney injury, what should it be in euvolemic patients in Na+ balance with normal renal function?
- prerenal azotemia
- acute tubular necrosis
<1%, if >1% can conclude it is acute tubular necrosis
UNLESS on diuretics
Specific gravity of serum, what is urine typically?
1.010, somewhere above that unless over hydrating then it will be diluted and lowered
Prerenal azotemia vs ATN urinalysis
normal or with hyaline casts, brown granular casts and cellular debris
Positive heme without positive blood on urinalysis, is indicative of this disease…
…rhabdo
+1 or +2 urine glucose on urinalysis is indicative of serum glucose levels of…
190-220
Leukocyte esterase on urinalysis indicates….
nitrite reduction on urinalysis indicates…
WBC in urine
Infection
Infection
Bright red blood tainted urine indicates the bleed is coming from the ___, while dark red indicates it is coming from the ____
lower urinary tract, kidney
A urine specimen that does not test positive via urinalysis for urobiligen is ___ a urine specimen that tests positive for bilirubin via urinalysis is ___
bad, bad
Micral test for microalbuminuria definition
The gold standard test for early detection of glomerular disease, test for microalbumin in the urine
Microscopic urine analysis detects for these 3 things
- cells
- crystals
- casts
In a blood positive urinalysis, diabetic, kidney infected, metabolic, or kidney stone patient, what should be ordered alongside a urinalysis?
Microscopic urine analysis
Red cells on a microscopic urine analysis is indicative of what anatomic location? What about red cell casts and what disease? What about white cell casts and what disease? What disease state is about white blood cells in urine? What do muddy brown casts in urine indicate?
Renal pelvis down, nephron (glomerulonephritis), nephron (pyelonephritis), bladder infection, tubular damage
Blood present at start of stream and then becomes clear indicates…
Blood present through the middle of the stream indicates…
Blood present at the end of the stream indicates…
- urethral bleeding
- bladder or above
- prostate and trigone bleeding
Common prerenal diseases (4)
- azoemia
- congestive heart failure
- hypovolemia
- hemorrhage
Healthy BUN:Cr ratio
between 10:1 and 20:1
Common postrenal kidney diseases (2)
- severe acute tubular necrosis
- obstruction
Common intrinsic renal diseases (3)
- glomerulonephritis
- proteinuria
- nephrotic syndrome
Orthostatic proteinuria
Benign condition frequently seen in children where proteinuria is seen after periods of standing but not sitting, can be tested for by sampling first urine in morning
What kidney conditions would you use ultrasound to detect? (3) Why is this the preferred imaging modality?
- hydronephrosis
- kidney stone
- renal artery stenosis
No radiation
Significant bacteruria is when there are ____ml of a single organism
100,000 (nonpregnant patient)
1 cause of renal artery stenosis, as well as 2 other common ones
Atherosclerosis, fibromuscular dysplasia, takayasu arteritis
Onset of hypertension before age 30 strongly suggests…
…Renal artery stenosis
3 clinical features of renal artery stenosis
- unexplained hypokalemia (due to aldosterone release)
- abdominal bruits
- abrupt onset of hypertension before age 30
The risk factors for Renal artery stenosis are the same as those for….
…coronary artery disease
A rare but significant symptom of bilateral renal artery stenosis
Unexplained flash pulmonary edema
2 labs/diagnostic studies for renal artery stenosis (gold standard and the cheaper preferred method)
- Renal arteriogram (invasive but almost guaranteed to find)
- renal ultrasound (cheaper and less iinvasive)
2 Treatments for renal artery stenosis (why are we cautious with one of them)
- medical management of hypertension with ACEI or ARB (use caution because already have decreased GFR)
- revascularization for severe cases
Renal artery stenosis prognosis
4 year mortality rate up to 40%, improved survival with treatment
Fibromuscular dysplasia affects ___ 2-10x more and its cause is…
women, unknown
What system is used to classify fibromuscular dysplasia today?
Angiographic classification system
Fibromuscular dysplasia definition
A fibrotic change in one of the layers of vasculature in medium sized vessels that often affects the carotid or renal arteries creating aneurisms that look like “beads”
Fibromuscular dysplasia presentation (5)
- hypertension
- headache
- pulsatile tinnitus
- neck pain
- cervical bruit
Fibromuscular dysplasia mech of action
Symptoms of hypertension, headache, neck pain, etc are result of ischemia due to stenosis, dissection occlusion of arteries, and rupture of aneurysms
Fibromusucular dysplasia prognosis
Shorter duration of Hypertension, better outcomes
Takayayasu arteritis definition, what sex is it most common in? Where is it most often found?
Inflmammatory arteritis of the aorta, females, Asia
Takayayasu arteritis clinical presentation (3)
- Female with uncontrolled hypertension
- <40 years old
- diminished pulse and limb claudication
The human kidney can tolerate ___ minutes of ischemia
60-90
Treatment of renal artery occlusion
-heparin followed by oral coumadin, potentially surgical intervention
Polyarteritis nodosa definition
Very very rare systemic arterial vasculitis
Polyarteritis nodosa 3 diagnostic criteria
1) necrotizing vasculitis affecting small arteries
2) no association with primary or secondary glomerulopathy
3) not an ANCA associated vasculitis
Polyarteritis nodosa mechanism of action
- autoimmune reaction where immune cells attack the arteries
Polyarteritis nodosa treatment (2)
Steroids and autoimmune suppression
Kawasaki disease clinical presentation (5)
- a fever lasting longer than 5 days
- bilateral bulbar conjunctival infection
- oral mucous membrane changes
- erythema of palms and soles and rash
- cervical lymph adenopathy
Kawasaki disease definition
A systemic vasculitis uncommon to be of renal origin
Kawasaki disease treatment
- Treatment within 10 days needed
- high aspirin dose (even in children)
- IVIG
Reye syndrome
A severe encephalopathy that also affects the liver resulting from children recovering from viral illness and associated with aspirin treatment
Atheroembolitic disease definition
Cholesterol crystal embolism occuring due to wide spread atherosclerosis
Thrombotic thrombocytopenic purpura characteristics (3)
Fever, purpura, CNS signs
Hemolytic uremic syndrome
Hemolysis often following gastrointestinal infection where toxins cause hemolysis affecting most often children putting them into renal failure
Triad of hemolytic uremic syndrome
- Thrombocytopenia
- hemolytic anemia
- acute renal failure
