Potassium Flashcards
former name of potassium
kalium
must NEVER be administered IV push as it can immediately stop the heart <3
potassium
RBC in K+ is _?
23x of plasma/serum potassium
major intracellular cation, give corresponding values
potassium (105 mmol/L in RBC
Critical Value: Hypokalemia
2.5 mmol/L
Critical Value: Hyperkalemia
6.5 mmol/L
Male Reference Range of Potassium in Plasma
3.5-4.5
reference range of serum potassium
3.5 - 5.1 mmol/L
reference range of serum potassium is only __ of total body K+
2%
this hormone can also regulate potassium
aldosterone
In this organ 70-80% of filtered K+ is reabsorb (proximal tubules)
kidney
it results to rapid entry of K+ in the cell
acute K+ elevation
Female Reference Range of Potassium in Plasma
3.4 - 4.4
ref range of K+ in urine (24h)
25-125 mmol/d
slight increase/decrease of potassium can seriously affect this muscle
potassium
In terms of abnormality, it is the single most important analayte
potassium
when aldosterone acts in DCT, it reabsorbs Na, in turn this electrolyte is excreted
potassium
it promotes cellular uptake of potassium
insulin
In acute elevation of potassium, it results to the rapid entry of K+ into the cell, this mechanism happen because?
it’s an attempt to lower potassium in serum
true/false
beta blockers which are therapeutic drugs specifically cardioactive drugs promotes cellular uptake of K+
false (impairs)
hypokalemia may result in?
arrythmia and paralysis
potassium levels with <2.5mmol/L causes __?
tachycardia
most common cause of hypokalemia (extra renal)
diarrhea
Enumerate causes of Hypokalemia
• GIT loss
• Renal loss
• Cellular Shift
• Decreased K+ Intake
It causes increased loss of potassium in stool
large doses of laxatives
True/False
Cathecholamines is involved in cellular uptake of Potassium
True
hyperkalemia: 6-7 mmol/L can alter?
ECG TRACE
this concentraton of K+ can cause lack of muscle excitability/weakness
8mmol/L
K+ conc that can cause cardiac arrest
10mmol/L
preferred sample for K+ lab analysis
heparinized plasma
it mimics the function of aldosterone
cortisol
cathecholamine hyper or hypoglycemia?
hyperglycemia
It promotes decrease in hydrogen ions, which then promotes excretion of potassium
renal tubular acidosis
former name of potassium
kalium
Explain why cushing syndrome results to hypokalemia (renal loss)
it involves increase in cortisol which is secreted in the adrenal cortex that MIMICS action of aldosterone
alkalosis causes hypokalemia, in what way?
When blood pH is alkaline, it will make H+ ions exit the cell to normalize blood pH which in turn makes the K+ enter the cell leading to hypokalemia
hypomagnesemia enhances what?
secretion of aldosterone
Explain how Hyperaldosteronism causes hypokalemia
PISO
Hyperaldosteronism causes sodium to be absorbed and potassium to be excreted.
It causes hypokalemia because of immature wbcs
acute leukemia
Pseudohypokalemia only occurs during analysis and when your patient has?
leukocytosis which takes up potassium if sample left at RT
how many percentage of filtered K+ does kidneys reabsorb
70-80%
It’s a disease that causes hyperkalemia because all adrenal hormones are affected
addison’s disease
explain why acidosis causes hyperkalemia
when blood is acidic, H+ ions will enter the cell, which in turn makes K+ exit the cell entering blood leading to Hyperkalemia
I was so busy that I forgot to centrifuge the whole blood sample that is stored in the ref.
can i still use this blood sample?
no, because it is a variable in lab analysis of potassium, this action promotes exit of K+ from cell which will lead to false increase
An 18 year old patient fresh from volleyball practice came to the lab, a request came that she should be tested for potassium levels.
what should we do?
explain that she can’t be tested for potassium levels because exercise and prolonged standing causes false increase in potassium levels by 10-20%
An intern took the blood sample from the patient that will be tested for potassium levels, it was noticeable that the procedure took more than 1 minute.
what can you notice in this case?
the blood collection procedure took more than one minute, meaning there is a prolonged tourniquet application, that will cause false increase in K+
An intern carefully instruct the patient to fist clench, during blood testing for potassium.
what can you say?
you should not instruct your patient to fist clench because it will cause cellular exit of K+
True or False
It is okay to use a lipemic sample in potassium testing because it does not necessarily affect K+
False, it will cause false increase of serum potassium
Potassium: Slight hemolysis - values
(50mg/dl hgb)
3% increase in K+
Potassium: Gross hemolysis - values
(>500 mg/dl hgb)
30% inc K+
variable values: mild moderate excercise
0.3-1.2 mmol/l inc
variable value: vigorous excercise
also, give an example
2-3 mmol/l inc (fist clenching)
ISE unexcited or excited?
unexcited
ISE k+ specific membrane
valinomycin
K+ lab method: colorimetry (___)
lockhead and prucell
Flame emission photometry: excited or not?
excited
true or false
hyperaldosteronism = hypernatremia = hypokalemia
true
T/F
Diabetes Mellitus causes hyponatremia, and hypokalemia
false
hyperglycemia causes hyponatremia
DM causes hyperkalemia
why can’t you use K2 (versene) in a blood sample that will be tested for K+
dipotassium EDTA
Acidosis values in hyperkalemia
inc 0.2-1.7 mmol/l/0.1 ph unit decrease
T/F
a female patient experiences hyperkalemia 128mmol/d in her urine sample. It also means that she has hypoaldosteronism and hypernateremia
t
why plasma is preferred over serum in potassium lab analysis?
serum is 0.1-0.7 mmol/l higher than plasma
3 specimen accepted in potassium analysis
heparinized plasma, serum, urine
major cation inside the cell
potassium
