Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
55 Cards in this Set
- Front
- Back
|
explain the 60-40-20 rule for fluid compartments
|
total body water is 60% of body weight
Intracellular fluid is 40% of body weight Extracellular fluid is 20% of body weight |
|
|
Three reasons for oliguria
|
low blood flow to kidney
kidney pathology post-renal obstruction |
|
|
normal urine output in adults?
|
>1mL/kg/hr
|
|
|
for each degree celsius above 37C, how much extra insensible losses per day?
|
100mL/day
|
|
|
what is the standard maintenance fluid used?
|
D5 1/2 NS +/- 20mEq KCl
|
|
|
What portion of D5W remains intravascular? Why?
|
1/12 because glucose freely permeates all fluid compartments and intravascular fluid space is only 1/12 of total body water
|
|
|
100/50/20 rule for maintenance fluids
|
100 mL/kg for first 10 kg, 50 mL/kg for second 10 kg, 20 mL/kg for every 1kg over 20kg
divide by 24 for hourly rate |
|
|
4/2/1 rule for maintenance fluids
|
4 mL/kg for first 10 kg, 2 mL/kg for second 10 kg, 1mL/kg for every 1 kg over 20
this is HOURLY estimation |
|
|
pre-renal azotemia from hypovolemia - significant lab values?
|
Increased serum Na, decreased urine Na, BUN/Cr >20:1, FeNa <1
|
|
|
4 primary diseases that cause fluid-retention
|
CHF, nephrotic syndrome, cirrhosis, ESRD
|
|
|
hyponatremia + urine Na >20mmol/L =?
|
salt-wasting nephropathy, diuretic overuse, or hypoaldosteronism
|
|
|
hyponatremia + urine Na >40mmol/L suggests what condition?
|
SIADH
|
|
|
treatment of severe hypotonic hyponatremia (Na+ <110 mmol/L)? what is possible complication?
|
hypertonic saline to increase Na+ 1 to 2 mEq/L per hour
risk of central pontine myelinolysis if increase >8mEq/L in 24 hours |
|
|
one renal and one extra-renal cause of HYPOVOLEMIC HYPERNATREMIA
|
renal: osmotic diuresis (commonly glycosuria)
extra-renal: diarrhea |
|
|
common disorder causing ISOVOLEMIC HYPERNATREMIA
|
diabetes insipidus
|
|
|
CNS effects of Hypernatremia vs. Hyponatremia
|
in hyponatremia, get CNS cell edema
in hypernatremia, get CNS cell dehydration |
|
|
common causes of Hypervolemic Hypernatremia
|
Cushing's syndrome, iatrogenic (too much parenteraly NaHCO3), glucocorticoids
|
|
|
how to differentiate nephrogenic vs. central diabetes insipidus?
|
Desmopressin challenge: if response to desmopressin, there is a CENTRAL process
|
|
|
how to calculate FREE WATER DEFICIT?
|
Total Body Water (1 - (actual Na+ / desired Na+))
|
|
|
how is total calcium and free ionized calcium affected by Hypoalbuminemia?
|
total calcium is decreased, free ionized calcium is unchanged
|
|
|
how to calculate free ionized calcium?
|
Total calcium - (serum albumin x 0.8)
|
|
|
how does pH affect total calcium and free ionized calcium? why?
|
increased pH causes DECREASED free ionized calcium by enabling albumin to bind more
i.e. in alkalemic states, total calcium is normal but free ionized calcium is LOW |
|
|
three hormones involved in Calcium metabolism? what are their targets?
|
hormones: PTH, Calcitonin, Vitamin D
targets: Kidney, Gut, Bone |
|
|
PTH affects on Kidney, Gut, Bone?
|
Kidney: inc. Calcium resorption, decreased phosphate resorption
Gut: activation of Vitamin D Bone: increased bone resorption |
|
|
Calcitonin affects on Kidney, Gut, Bone?
|
Kidney: decreased calcium resorption, increased phosphate resorption
Gut: decreased Calcium absorption Bone: dec. bone resorption |
|
|
Vitamin D affects on Kidney, Gut, Bone?
|
Kidney: inc. Calcium resorption, decreased phosphate resorption
Gut: Inc. calcium resorption, inc. phosphate resorption Bone: increased bone resorption |
|
|
why SPECIFICALLY does renal insufficiency lead to hypocalcemia?
|
decreased 1,25-Vitamin D
|
|
|
what other value should be looked at when total Calcium is low?
|
albumin - if low then this is why
|
|
|
hypocalcemia should always be in the differential for what ECG finding?
|
Prolonged QT
|
|
|
acute pancreatitis can be associated with what electrolyte abnormality?
|
hypocalcemia - calcium deposits in pancreas occur
|
|
|
emergency treatment for symptomatic hypocalcemia
|
IV calcium gluconate
|
|
|
Barterr's syndrome: what is it?
|
autosomal recessive defect in salt reabsorption in ascending limb --> juxtaglomerular apparatus hyperplasia --> inc. renin and aldosterone --> hypokalemia
|
|
|
urine potassium cutoff to differentiate GI loss vs renal loss
|
GI loss: <20mEq/L
Renal Loss: >20 mEq/L |
|
|
Hypo kalmia predisposes patients to what drug toxicity?
|
Digoxin
|
|
|
what are hyperkalemias effects on ammonia?
|
hyper kalmia inhibits renal ammonia synthesis and reabsorption leading to acidosis and more potassium release from cells
|
|
|
at what value of hyperkalemia do ECG findings occur?
|
6.0 mmol/liter
|
|
|
ECG findings in hyperkalemia
|
PEAKED T waves, prolonged PR, QRS widened and can fuse with T wave
in severe hyperkalemia: VFib and cardiac arrest |
|
|
with hyperkalemia and ECG changes what is the first drug to administer?
|
IV calcium gluconate to stabilize cell membranes
use CAUTION when administering to digoxin patients bc hypercalcemia predisposes to dig toxicity |
|
|
largest reservoir of Magnesium in the body?
|
Bone - two-thirds
|
|
|
most common cause of Hypomagnesemia?
|
malnutrition/steatorrheic states
|
|
|
hypomagnesemia makes what other two electrolyte abnormalities difficult to treat?
|
hypokalemia and hypocalcemia
|
|
|
what two electrolyte abnormalities frequently (but not always) coexist with hypomagnesemia?
|
hypokalemia and hypocalcemia
|
|
|
ECG changes in hypomagnesemia?
|
prolonged QT interval, T wave flattening, and in severe cases: Torsade de pointes
|
|
|
treatment of Mild and Severe hypomagnesemia?
|
mild: oral Mg2+ supplement (magnesium oxide)
Severe: parenteral Mg2+ (magnesium sulfate) |
|
|
most common cause of HYPERmagnesemia?
|
renal failure
|
|
|
common signs of HYPERmagnesemia?
|
loss of DTRs, somnolence --> coma, nausea, weakness
|
|
|
ECG findings in HYPERmagnesemia?
|
similar to hyperkalemia: increased PR interval, widened QRS complex, elevated T waves
|
|
|
treatment of severe HYPERmagnesemia?
|
first: administer IV calcium gluconate to stabalize cardiac cell membranes
saline, furosemide, dialysis (renal failure patients) |
|
|
serum cutoffs for HYPO vs. HYPERphosphatemia
|
HYPO: <2.5 mEq/L
HYPER: >5 mEq/L |
|
|
two most common causes of hypophosphatemia?
|
alcoholism and DKA
|
|
|
most common cause of hyperphosphatemia?
|
decreased renal excretion due to renal failure
|
|
|
main clinically relevant finding in prolonged hyperphosphatemia?
|
hi PO4(3-) in blood causes metastatic calcification and soft-tissue calcifications by crashing out of solution
HYPOCALCEMIA as sequela, leads to neurologic changes |
|
|
how to predict if phosphate-calcium deposition will ocurr?
|
(serum calcium x serum phosphorus) >70
|
|
|
equation for Anion Gap?
|
AG = [Na+] - ([Cl-] + [HCO3-])
|
|
|
Normal range of Anion Gap?
|
8 to 15
|
