Magnesium (F) Flashcards
What are the characteristics of Mg?
1) It is the 4th most abundant cation
2) It is the 2nd most abundant intracellular cation
Where are Mg stored and their corresponding percentages?
1) Bones (majority): 53%
2) Muscles and soft tissues (some): 46%
3) Serum and RBC (small amt): 1%
What are the fxns of Mg?
1) Cofactor of 300 enzymes >
2) Fxns in cardiovascular aspect
3) Fxns in metabolic aspect
4) Fxns in neuromuscular health
5) Fxns in maintaining the structures of DNA and RNA
6) Regulates movement of K across the myocardium
What are the hormones that are responsible for the regulation of Mg?
1) Parathyroid hormone (PTH)
2) Aldosterone
3) Thyroxine (T4)
What are the mechanisms of action of PTH in terms of regulation of Mg?
1) It increases renal absorption of Mg
2) It increases intestinal absorption of Mg
What is the mechanism of action of aldosterone and T4 in terms of regulation of Mg?
These increases renal excretion of Mg
Who are the pts where hypomagnesemia is observed?
1) Hypomagnesemia is observed in hospitalized individuals in intensive care unit (ICU)
2) Or for those who are receiving diuretic therapy / digitalis therapy
True or False
Hypomagnesemia rarely occurs in non-hospitalized pts
True
What is the main cause of deficiency of Mg (/ hypomagnesemia)?
Reduced intake (of Mg)
What are the 3 hormones and 1 electrolyte (in their abnormal lvls) that are related w/ hypomagnesemia?
1) Hyperparathyroidism
2) Hyperthyroidism
3) Hyperaldosteronism
4) Hypercalcemia
What is hyperaldosteronism (/ what is its effect)?
It is the condition whereas there is an excess in serum Na
What is the cause of pseudohypomagnesemia?
It is the condition that is due to hyperaldosteronism
What is hyperthyroidism (/ what is the event present in this condition)?
It is the condition whereas there is an increase renal excretion
Is diabetes related to hypomagnesemia?
Yes
What are the different drugs that are related w/ hypomagnesemia?
1) Diuretics
2) Gentamicin
3) Cisplatin
4) Cyclosporine
What is the result if diuretics, gentamicin, cisplatin, and cyclosporine are intake by the pt (in relation to hypomagnesemia)?
Increased renal loss
Can excess lactation lead to hypomagnesemia?
Yes
How is excess lactation associated w/ hypomagnesemia?
Because due to excess lactation, there is an increased use / utilization of Mg w/c are lost through milk production
What are the causes of hypomagnesemia?
1) Reduced intake (of Mg)
2) Hyperaldosteronism
3) Pseudohypomagnesemia
4) Hyperthyroidism
5) Diabetes
6) Medications
a. Diuretics
b. Gentamicin
c. Cisplatin
d. Cyclosporine
7) Excess lactation
True or False
Hypermagnesemia is observed more frequently > hypomagnesemia
False, because hypomagnesemia is observed more frequently > hypermagnesemia
What are the causes of hypermagnesemia?
1) Due to renal failure
2) Medicines
a. Antacids
b. Enemas
c. Cathartics
3) Decreased T4 and growth hormone (GH) production
4) Multiple myeloma
a. Bone cancer
How can multiple myeloma and bone CA cause hypermagnesemia?
Because if these conditions are present, there is an increased bone loss, w/c results to the release of Mg from the bones
What are the sx considerations for Mg determination?
1) Non-hemolyzed serum should be used
2) Hemolysis should be absent
3) Anticoagulants such as oxalate, citrate, and EDTA should not be used
Why should hemolysis (in the sx) be absent in terms of Mg determination?
Because hemolysis can cause false increase of Mg
What are the rgnts present in the rgnt set for Mg?
1) Buffer (/ buffer rgnt)
2) Color developer (/ color rgnt)
3) Mg std
What is the result if Mg (present in the sx) combines w/ calmagite in an alkaline medium?
Red colored complex
If spectrophotometer is used for determination of Mg lvls, what is the wavelength used?
530 nm
What is the meaning of EGTA?
Egtazic acid
What are the actions of EGTA?
1) It serves to complex and prevent Ca interference
2) It acts as a surfactant that eliminates the effect of protein
What is the process (/ steps) for Mg determination?
1) Prep the ff tubes (blank, standard, and sample)
2) Add Mg working rgnt (1,000 uL)
3) Add the sx (10 uL) to the respective test tubes
4) Incubate for 5 mins
5) Read and record A (via spectrophotometer) at 530 nm
What is the normal reference range for Mg?
1.3 - 2.5 mEq/L or 1.3 - 2.5 mmol/L
