Flashcards in Intro to diuretics and renal disease Deck (72)
What are the 3 common uses of diuretics?
- control ECF volume
- increase urine volume output
- lower ECF volume
What conditions would result in needing to control ECF volume?
- hypertension: non-renal failure induced elevations in ECF
- edema: trauma, congestive heart failure
What do most diuretics target?
- since Na stays in the lumen, so does water
Why does decreased resorption of other electrolytes occur with diuretic use?
Since water remains in the tubules, there is an increased flow rate through the tubules which leads to diminished resorption of electrolytes (Ca, Mg, etc) that rely on a concentration gradient for passive reabsorption
- do not see an increase in the concentration of other electrolytes that would normally occur with reabsorption of Na and water (so, no increase in concentration = no concentration gradient established)
Diuretics are considered to be potassium ______
- increased Na, water, and flow rate prevents an increase in K concentration at the level of the distal tubule and collecting duct, promoting more rapid excretion of K+
What diuretics are not K+ wasting?
Those that target Na resorption by the principle cells of the distal tubules and collecting ducts
Increase tubular osmolarity
- use with excess glucose or urea
- ex: mannitol
Loop blocker diuretics
Inhibit Na-K-Cl cotransport
- blocks concentrating and diluting ability
- increase urine output of Na, Cl, K, etc
- increase quantities of solutes delivered to distal parts of nephrons, which act as osmotic agents
- disrupt countercurrent multiplier system by decreasing absorption of ions from Henle into the medullary interstitium
- ex: furosemide
Inhibit Na Cl cotransport by targeting the Na-Cl co transporter on the apical membrane of early distal tubules
- ex: hydrochlorothiazide
Carbonic anhydrase inhibitors
Inhibit H secretion and HCO3 reabsorption = blocking Na reabsorption
- disadvantage: can cause acidosis due to loss of bicarb
- used to manage HYPP
- ex: acetazolamide
Blocks aldosterone receptor in the cortical collecting tubule principle cells = decreased reabsorption of Na and secretion of K (leading to a decrease in excretion of K)
- ex: spironolactone
Na channel blocker
Blocks Na entry into the Na channels of the apical membrane of the collecting tubule cells that were inserted under the influence of aldosterone
- leads to decreased activity of Na K ATPase pump, reducing secretion of K
- ex: amiloride
Kidney is the primary organ responsible for long term maintenance of ___
What are the 6 main functions of the kidney?
- excretion of metabolic waste products
- regulation of acid-base balance
- control of arterial pressure
- regulation of water and electrolyte excretion
- secretion, metabolism, and excretion of hormones
- excretion of foreign chemicals
Accumulation of nitrogenous waste products
- urea, creatinine, ammonia
Hyperkalemia causes ______
Arrhythmias, neuromuscular dysfunction
Affects CNS function and all cell processes
- retention of H and organic acids, loss of bicarb
Hypertension or hypotension
Failure to excrete or conserve sodium and water
- failure to produce renin = no angiotensin
- edema or dehydration
What 2 hormones are produced by the kidney?
- renal erythropoietic factor: absence leads to anemia
- 1,25 dihydroxycholecaliferol (Vit D): absence leads to osteomalacia
Does renal disease have subclinical signs?
- kidney can be deteriorating for a while without clinical signs appearing
Renal disease clinical signs
- general malaise
- weight loss
Prerenal disease will typically result in _______
Diminished renal blood flow
What are the 3 main causes for diminished RBF?
- volume loss: diminished renal perfusion (diarrhea, hemorrhage, etc)
- volume redistribution: endotoxemia, septicemia, 3rd space sequestration
- cardiovascular failure: diminished renal perfusion (myocardia, valve disease, etc)
Dehydration is typically a ______ issue
SpGr should be ____ in dehydration
How does the macula densa react during states of mild dehydration?
Induces afferent arteriolar dilation and release of renin from juxtaglomerular cells results in efferent arteriolar constriction
- both work to preserve GFR and glomerular hydrostatic pressure, ensuring filtration/elimination of Cr
Why does BUN increase during dehydration?
Low flow states cause increased time for reabsorption of urea
- ADH induced carrier proteins facilitate urea reabsorption from medullary collecting tubules
High urine SpGr with a high BUN and Cr indicates ____
High BUN and Cr with a lower urine SpGr indicates _____