Renal Flashcards by Shay Edgeston

Acid base balance involves

Bicarbonate reabsorption

H+ elimination

(maintains urine pH >4.5)

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What hormones do the kidneys produce?

Renin

Erythropoietin

Vitamin D3

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The kidneys receive how much of the cardiac output?

25%/minute

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RBF is maintained between

50-180mmHG

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There is a direct relationship between

RBF & glomerular filtration

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When does filtration to the kidneys cease?

MAP below 50

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The kidneys can override

The SNS and cause vasodilation

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What happens when the kidneys release renin?

There is an increase in aldosterone secretion, causing an increase in BP

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What is the strongest trigger for aldosterone release?

HYPERKALEMIA (even more than renin)

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Aldosterone will cause reabsorption of_______ and secretion of______

Reabsorb Na+ and Water

Secrete K+

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Antidiuretic hormone will increase

Distal tubular permeability to water

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The renin/angiotensin causes

The conversion to angiotensin II, which causes vasoconstriction

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Renin/ angiotensin will cause reabsorption of ____ & secretion of _____

Reabsorb NaCl & Water

Secrete K+

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Renin/angiotensin will cause release of

Aldosterone & ADH (antidiuretic hormone)

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What drugs inhibit RAAS activation?

ACE inhibitors

ARBS

Renin antags

Aldosterone antags

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ANF will cause vaso______ and may increase RBF & _____

Dilation

GFR (afferents are dilated)

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Atrial natriuretic factor will increase

Urine flow & Na+ EXCRETION (to rid the body of extra fluid)

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Renal prostaglandins affect

Excretion of substances

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Prostaglandin E2 & thromboxane A2 can

Modulate renal effects of other hormones

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Prostaglandin E2 vaso______

Thromboxane A2 vaso ______

Dilate

Constricts

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Urine filtrate formation involves these 4 steps

Filtration

Reabsorption

Secretion

Elimination

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What happens when fluid is filtered in the renal corpuscle?

There is passive movement of water & small dissolved molecules from the plasma into the BC filtrate

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GFR is increased by

RBF

Afferent arteriole vasodilation

Efferent arteriole vasoconstriction

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GFR is decreased by

Decreased RBF

Afferent constriction

Efferent dilation

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NSAIDS ________afferent arterioles, causing potential kidney damage

Constrict

ACEI/ARBs ______efferent arterioles, causing kidney_______

Dilate Protection

A decrease in flow & GFR will inhibit prostaglandin production, causing

Vasoconstriction

Reabsorption is the movement of substances from

The tubular filtrate & back to the plasma

What substances are usually reabsorbed?

Water Electrolytes Glucose Amino Acids

Reabsorption can be _____ or ____

Active (Na/K ATPase) Passive (diffusion or osmosis)

Secretion is the

Movement of substances from the plasma into the tubular filtrate

What substances are secreted?

Organic anions Drugs Foreign substances

Secretion can be ___ or ____

Active or Passive

Na+ reabsorption is greatest in the

Proximal Convoluted Tubule

In the absence of ADH, the final urine will be

Dilute

With the presence of ADH, the final urine will be

Concentrated

What is the primary therapeutic effect of diuretics?

Inhibit Na+ reabsorption

What are the 2 primary reasons we give diuretics?

Used for HTN & CHF

What drugs target the PCT?

Carbonic Anhydrase Inhibitors Osmotic Diuretics

What drug works in the Loop of Henle?

Loop diuretics

What drug works in the DCT?

Thiazides

What drugs work in the collecting ducts?

Aldosterone Antagonists ADH antagonists

Carbonic anhydrase inhibitors (Acetazolamide [Diamox]) work by

Blocking carbonic anhydrase activity

Carbonic anhydrase inhibitors decrease the reabsorption of

Na+ HCO3- Water Causing natriuresis, diuresis & alkaline urine

Carbonic anhydrase inhibitors increase the excretion of____

K+

Carbonic anhydrase inhibitors increase the reabsorption of ____

Cl-

Carbonic anhydrase inhibitors can lead to this metabolic change

Metabolic Acidosis

Carbonic anhydrase inhibitors can cause the formation of

Kidney stones

Carbonic anhydrase inhibitors can cause these electrolyte imbalances

Hypokalemia Hyperchloremia

Carbonic anhydrase inhibitors can cause

Fatigue Paresthesias Tolerance after 2-3 days

Osmotic diuretics are

Inert chemical substances that are freely filtered by the glomerulus (increasing osmolarity of fluids)

Osmotic diuretics decrease the reabsorption of

Water

Osmotic diuretics are given to treat

IOP Glaucoma ICP

Osmotic diuretics can cause these electrolyte abnormalities

Hypokalemia Hyponatremia

Osmotic diuretics can cause this in the vein

Thrombophlebitis when infiltrated

Osmotic diuretics can cause this, so caution when giving to patients with LV dysfunction or pulmonary edema

Increases plasma volume due to initial increase in intravascular volume

Osmotic diuretics can worsen

cerebral edema in patients with non-intact BBB

With long term use, Osmotic diuretics can cause

Hypovolemia

What is the IV dose of Mannitol?

0.25-2g/kg IV

What is the onset and duration of Mannitol?

IV onset: 10-15 min Duration: 6-8 hours

With Mannitol, the

Surgar alcohol doesn't cross the cell membranes

When does Mannitol reduce ICP?

~60-90 min

Mannitol may prevent

Preoperative renal failure in ATN by causing vasodilation, which improves RBF, removes renal toxins & necrotic debris, & is a scavenger of free O2 radical, which may prevent cellular injury

Loop Diuretics work by blocking...

Na+/K+/2Cl co transporter

Loop diuretics decrease the reabsorption of

Na+ K+ Cl- Water Ca+ Mg+

What is natriuresis?

Removal of Na+

What is the most potent diuretic?

Loop Diuretics

Loop diuretics cause less

Vasodilation than thiazines, leading to a less effect in lowering HTN

Loop diuretics can increase the formation of

Prostaglandins

Loop diuretics can cause these electrolyte imbalances

Hypokalemia Hyponatremia Hypocalcemia Hypomagnesemia

Loop diuretics can cause this metabolic change

Metabolic Alkalosis

Which diuretic can lead to gout, renal ischemia injury, & hyperuricemia?

Loops

Which diuretic can cause ototoxicity & tinnitus?

Loops

Loop diuretics can increase the nephrotoxic effects of

Aminoglycosides & cephalosporins

What is the dose of Lasix?

20-40mg IV MAX 200 mg/dose

What is the onset & duration of Lasix?

Onset: 5-10 min Duration: 2-6 hours

What diuretic can cause an acute tolerance, leading to RAAS activation, resistance in HF patients, and may require the addition of a thiazide?

Loops

Thiazide diuretics block the

Na+/Cl cotransporter

Thiazides decrease the reabsorption of

Na+ Cl- Water

Thiazides increase the excretion of

K+

Thiazides increase the reabsorption of

Ca+

Which diuretic is first line in the treatment of HTN?

Thiazides, since they decrease the fluid volume, cardiac output, & cause vasodilation

Thiazides are also used to treat

Hypocalcemia

Thiazides can cause these electrolyte abnormalities

Hypokalemia Hyponatremia Hypercalcemia Hypomagnesemia Hypochloremia Hypophosphatemia

Thiazides side effects include

Hyperuricemia Metabolic Alkalosis Hypovolemia HOTN HYPERglycemia Cross-reactivity in sulfa allergy

In which 2 ways do potassium-sparing diuretics work?

Epithelial Na+ channel (ENaC) blockers Aldosterone receptor antagonists

ENaC blockers decrease the reabsorption of

Na+ Water

What are examples of ENaC blockers?

Triamterene Amiloride

Aldosterone receptor antagonists decrease the reabsorption of

Na+ Water

Aldosterone receptor antagonists inhibit

Na+/K+ ATPase

What are drug examples of Aldosterone receptor antagonists?

Spironolactone Eplerenone

Potassium Sparing diuretics decrease the excretion of

K+

Potassium Sparing diuretics can cause these electrolyte imbalances

Hyperkalemia Hyponatremia

Potassium Sparing diuretics can also cause

Metabolic Acidosis Dehydration HOTN Gynecomastia Decrease Androgen levels Dry skin Rash

Dopamine receptor Agonists inhibits

Na+/H+ exchange Na+/K+ ATPase

Dopamine receptor agonists increase

cAMP

Higher doses of dopamine receptor agonists will activate the SNS, causing...

Beta cardiac stimulation Alpha vasoconstriction

What is an example drug of a dopamine receptor agonists?

Fenoldopam

Fenoldopam has moderate activity at

Alpha 2

Fenoldopam increases & decreases...

Increases RBF Decreases SVR

Hypookalemia places the patient at greatest risk for

Arrhythmia Potentiating (increasing effect) of muscle relaxants Paralytic ileus

Why will hypokalemia enhance the effects of muscle relaxants?

When you are hypokalemic, the is more potassium in the plasma rather than inside the cells. This will cause the cells to hyper polarize, making it difficult to have an action potential

What is the typical wave form seen with hypokalemia?

U wave Prolonged QT Inverted T waves

What are patient risk factors for perioperative acute kidney injury?

>56 Active CHF Ascites DM HTN Male

What is a poor indicator of renal function?

MAP

Reducing sympathetic stimulation, minimizing increases ni intrathoracic & intraabdomiinal pressures can

Help maintain renal blood flow

Urine output can be a

Poor predictor of function

Nephrotoxic agents should be avoided & include

NSAIDS Contrast Antivirals Abx