Week 2 AKI Flashcards
What is Azotemia
an accumulation of nitrogen waste products in the blood
what is normal hourly urine output
0.5 mL/kg/h
what is the most common manifestation of an AKI
Oliguria
what are the 3 different types of renal failure
Pre
Intra
Post
what is pre renal failure
when there health factors external to the kidneys that result in reduced systemic circulation causing a reduction in renal blood flow and decreased GF (so the kidneys are working fine but there is just not enough blood flowing through them to filter properly)
What is intrarenal AKI
When there is direct damage to the renal tissue which causes impaired nephron function
What is post renal AKI
When there is a mechanical obstruction that blocks urine flow
what is the most common intrarenal AKI
Acute tubular necrosis
what are the three main causes of ATN
-Ischemia
-Nephrotoxins
-Sepsis
what are 4 causes of postrenal AKI
-BPH
-Kidney stones
-Trauma
-Tumor
What three meds are very hard on the kidneys
-Vancomycin
-NSAIDs
-ACE inhibitors
What are the different phases of ATN
Initiation
Maintenance
Recovery
what amount of urine over 24 hours is usually classified as oliguric
anything less than 400 ml/24hrs is usually classified as oliguric
what are 4 typical characteristics of urine for someone who experiencing oliguria from ATN
-Normal specific gravity
-High sodium
-Low urine osmolality (kidneys can’t concentrate urine)
-Urine with protein/RBC, WBC
What marks the beginning of a diuretic phase during the recovery phase of ATN
a gradual increase in urine output to around 1-3 L and it shows the kidneys have regained their function to excrete waste but still can’t concentrate the urine
What indicates someone is in the recovery phase of an AKI
A return to normal BUN, Creatinine and GFR towards normal ranges
How is the initiation phase characterized in ATN
Increase in:
-Creatinine
-BUN
-Decreased urine output
During the maintenance phase for people who are not experiencing oliguria what are the characteristics of their urine
-Dilute urine with low specific gravity
-Uremic toxins are not removed (so they stay in the body)
How long does oliguria usually last during the maintenance phase of ATN
Usually lasts 10-14 days but can last months in some cases
How can ATN cause metabolic acidosis
-Kidneys can not synthesize ammonia which is needed to excrete hydrogen
-The kidneys lose their ability to re uptake bicarbonate
Would someone with ATN typically have high or low sodium
Low sodium since the kidneys are no longer able to conserve it an excess amounts are excreted in the urine
What happens to potassium levels for someone who is experiencing ATN
Serum potassium levels increase because kidneys can no longer excrete potassium
What happens to calcium levels during ATN and why
-Vit D must be activated by the kidneys (so when there not working its not activated)
-Vit D responsible for absorption of calcium so not working no calcium absorption=hypocalcemia
What happens to phosphate levels during ATN and why
-Since there is hypocalcemia parathyroid hormone stims release of calcium from bones which also releases phosphate from bones
-Kidneys aren’t able to excrete phosphate so it builds up in the body
what is the best indicator for renal failure
Creatinine levels
why is BUN not the best indicator of renal failure
elevated BUN can occur for many reasons not just renal failure
What are the three phases of AKI
Oliguric
Diuretic
Recovery
What happens to potassium during the diuretic phase of AKI
potassium is low since it is being over excreted in the urine
What are common urinalysis findings in a patient with intrarenal AKI
-Urine sediment
-Casts
-protein
What are common urinalysis findings in a person with post renal AKI
-Hematuria
-pyuria (WBC’s or pus)
-Crystals
What information about the kidneys can a renal ultrasound show
-renal blood flow
-integrity of collecting systems
-anatomy and function
What information about the kidneys can a renal CT scan show
-Lesions
-Masses
-Obstructions
What information can an MRI provide about the kidneys
MRI’s not recommended since the contrast dye can be nephrotoxic
What are crystalloid fluids
IV fluids that contain water or electrolytes (ie normal IV fluids)
what can protect the myocardium from the toxic effects of hyperkalemia?
Calcium gluconate since it counteracts the effect of hyperkalemia on the myocardium
What medications can shift potassium back into cells
-IV regular insulin
-Salbutamol
-Sodium bicarbonate
What medications can promote potassium excretion
-Sodium polystyrene sulfonate (Kayexalate)
-Sodium zirconium cyclosilicate
-Patiromer
-Loop diuretics
What medications can exacerbate hyperkalemia
-ACE
-ARBS
-potassium sparing diuretics
Why are AKI patients more susceptible to bleeding
Uremia (waste products in blood) decreases platelet adhesion
What are hematological changes that occur during an AKI and why
-Anemia since the kidneys are no longer producing EPO
-lower WBC (so more at risk for infection)
