RENAL Flashcards
What is azotemia?
Elevated nitrogen containing compounds (urea, creatinine)
At what 3 locations can azotemia occur?
Pre, renal, or post-renal
If a patient has severe azotemia that is symptomatic and can cause metabolic acidosis and electrolyte disturbances – what is this known as?
Uremia
How do we stage AKI?
RIFLE (risk, injury, failure) class
AKIN (acute kidney injury network) stage
KDIFO (kidney disease improving global outcomes) guideline
What is something that a nurse would call and notify you about that has changed for the patient, that would trigger you to think about AKI?
Decreases in urine output to less than 3ml/kg over 6 hours (or 0.5ml/kg/hr)
**Falls under KDIGO
We should always be checking creatinine levels when someone first enters the hospital, and re-checking. What change would indicate to us AKI?
Rises greater than 0.3mg/dl
**Falls under KDIGO
What are some of the clinical manifestation of AKI?
Often none
Edema, HTN, decreased UO, and changes in labs
What lab changes would you note with AKI?
Albuminuria, increased BUN, hyperkalemia, and hyponatremia
What would be some examples of prerenal azotemia?
Dehydration!!!! → Hypovolemia (may include blood loss)
Prolonged renal ischemia (acute tubular necrosis)
What are the two components of ATN? What causes each?
Ischemia (prolonged pre-renal)
Nephrotoxicity (NSAIDs, Abx, contrast dye)
What are some causes of Renal (intrinsic) Azotemia?
Glomerulonephritis (immune modulated) vs. Nephrosis (ischemia, contrast, toxins, DIC, precipitation)
Nephritis → Immune modulated
Minimal change disease (nephrotic syndrome)
What are some causes of postrenal azotemia?
Urinary obstruction = Prostatism, tumors, calculi, occasional urethra obstruction
What are some classic diagnostic testing we do for AKI?
UA, BUN, Cr, K, Na, Phosphate, Ca, CBC, and Renal/Pelvic US
How do we prevent AKI?
Sustain renal perfusion (fluid balance, blood volume, BP)
Don’t clog the pipes → prepare for planned exposure to contrast dye and check labs before!
What is the #1 most important step for treating AKI?
You must figure out the cause!!!
How do we treat AKI?
Meticulous limitation of intake = water, meds, proteins, K, Na, phosphate
If everything fails then consider a renal consult → Dialysis
What must we have prepped and ready for a renal consult?
BMP, Mg, Phosphate, UA, hemoglobin, and Renal US
What are some underlying medical co-mordidities that can lead to chronic kidney disease?
AKI, HTN, DM, and vascular disease
If the GFR is 60-89, what stage CKD?
2 (mild)
If the GFR is 30-44, what stage CKD?
3B
If the GFR is less than 15, what stage CKD?
5 (end stage)
If we have a patient in the hospital with CKD, what’s out #1 goal?
To prevent the development of acute-on-chronic kidney disease
If we have someone in the hospital with CKD, how do we manage them?
Diet (low sodium, potassium, protein, and phosphate)
Avoid nephrotoxins (NSAIDs and contrast)
Water management (think about your IVF!!!)
What is the primary intracellular cation?
Potassium
AKI, CKD, diet high in potatoes or bananas, hemolysis, metabolic acidosis, beta blockers, insulin deficiency, or aldosterone antagonists – can all cause what?
Hyperkalemia
What do we see on EKG with hyperkalemia?
Peaked T waves! With widening PR, QRS
What do we see on PE with hyperkalemia?
Weakness and Paralysis
How can we treat hyperkalemia?
Treat the cause
IVF
Kayexelate
Limit potassium
Insulin + dextrose
Beta adrenergics (albuterol neb)
If a patient has metabolic alkalosis due to excessive V/D (laxatives) or renal diuretics/hypomagnesemia – what can they all lead to?
Hypokalemia
What do you see on PE with Hypokalemia?
Weakness, rhabdomyolysis
Glucose intolerance
What would you see on EKG with hypokalemia?
U waves
How do you treat hypokalemia?
Potassium replacement! (PO vs. IV for symptomatic, should be KCl)
ALWAYS CHECK Mg AND REPLACE IF NEED BE!!!
Consider hyperglycemia and DKA
What is the primary extracellular cation?
Sodium
***AKA we’re moving onto the natremias…
If we discover that someone is hypernatremic – what must we figure out next?
If their urine is dilute or highly concentrated
What would cause a patient to be hypernatremic with highly concentrated urine?
Extrarenal water loss (on a desert island)
Fever, sweating, diarrhea, mechanical ventilation
What would cause a patient to be hypernatremic with dilute urine?
Osmotic diuresis (something is in there, and it’s got to come out)
DKA, Diabetes insipidus (central = low ADH, Nephrogenic = unresponsive to ADH)
If we have determined that a person is hypernatremic with dilute urine – what do we need to figure out next?
Polyuric? (is their urine output greater than 3L/day)
If yes, is the urine osmolality: +300mOsm/L (indicating osmotic diuresis)
Or Less than 150mOsm/L (indicating diabetes insipidus)
If a patient is just dehydrated and that’s why they are hypernatremic – what do we do?
NS initially → transition to ½ NS
How fast can we correct hypernatremia due to dehydration?
SLOW!
No faster than 0.5mEq/L/hour (to avoid cerebral edema)
What does hyponatremia often indicate?
Increased water with relation to sodium
Often associated with elevated ADH
Almost all patients that are hyponatremic are they also: hypoosmolar or hyperosmolar?
Hypoosmolar
*Just don’t worry about hyperosmolar
So, when we figure out someone with Hyponatremic Hypoosmolar – what must we figure out next?
Volume status!
Hypervolemic, Hypovolemic, or Euvolemic
Assess with Hx, exam, Urine Na, and urine osmolality
What would be some causes for HypERvolemic Hyponatremic?
CHF!!! Cirrhosis or nephrotic syndrome → they have EDEMA
What would we see on labs with hypervolemic hyponatremic?
Na = 125 (140 is NORMAL)
Baroreceptors are increasing ADH secretion since circulation is inadequate (ADH is high) → thus the kidneys are retaining both water and salt
If a patient is hypOvolemic hyponatremic – where should we look for the source?
Renal or Non-renal causes
Renal = Urine Na 30+mmol/L
Non-renal = Urine Na less than 30mmol/L
If the urine Na is over 30 in a hypOvolemic hyponatremic patient – what are some possible causes?
Diuretics!!! (thiazides)
Primary adrenal insufficiency
Cerebral salt wasting
If the urine Na is less than 30 in a hypOvolemic hyponatremic patient – what are some possible causes?
GI!!!!
Vomiting, diarrhea, dehydration
If a patient is euvolemic but their labs come back with a sodium of 116 – what are they?
Euvolemic Hyponatremic
In a Euvolemic hyponatremic patient, what must we look at next?
Can they concentrate their urine
UrOsm 100+ (urine remains relatively concentrated, despite excess water in blood)
UrOsm less than 100 (unable to concentrate urine)
What are some causes of Euvolemic hyponatremia with concentrated urine?
SIADH!!!!
Secondary adrenal insufficiency, renal insufficiency, hypothyroidism
What are some causes of Euvolemic hyponatremia with inability to concentrate urine?
Psychogenic polydipsia (they’re literally drinking from the toilet)
Tea & Toast diet
So, like we said earlier almost all of Hyponatremias are associated with elevated ADH levels – what would cause elevated ADH in a hospitalized patient?
Pain, volume depletion, trauma, meds (SSRI, diuretics), neoplasms, neurophyschiatric meds
How do we treat acute symptomatic hyponatremia?
Saline (normal 0.9%)
Loop diuretic
Recheck Serum Na and Urine Osmol every 1-2 hours
How do we treat chronic symptomatic hyponatremia?
Brief stint of 3% saline (ALWAYS from nephrology input)
Stop NaCl when suren Na rises, Urine Osm falls, or symptoms resolve
What must we remember about the IVF we give for hyponatremia?
The UrOsm should be LESS than whatever you’re giving
How do you treat chronic ASYMPTOMATIC hyponatremia?
Fluid restriction (best/safest initial)
Increase solute intake
D/C offending agents
ADH receptor antagonist
How do you treat hypovolemic hyponatremia?
NaCl
