Upgrade to remove ads
Only $2.99/month

Magnesium

Terms in this set (39)

Magnesium
second most abundant cation in intracellular fluid
Magnesium Functions
-Promotes enzyme reactions within the cells during carbohydrate metabolism

-Helps the body produce and use ATP for energy

-Takes part in DNA and protein synthesis

-Influences vasodilation and cardiac muscle contractility

-Aids in neurotransmission

-Plays an essential role in the production of parathyroid hormone

-helps sodium and potassium ions cross the cell membrane (explains why magnesium affects sodium and potassium ion levels both inside and outside the cell)
Normal Magnesium Serum levels:
1.5 -2.5 mEq/L

-ranges differ for neonates and children
Magnesium and Calcium
-influences the body's calcium level though its effect on parathyroid hormone (PTH).

-PTH maintains a constant calcium level in extracellular fluid
Interpreting Magnesium levels
-Normally, the body's total serum magnesium level is between 1.5 and 2.5 mEq/L.

-This may not accurately reflect your patients actual magnesium stores because most magnesium is found within cells, where it measures about 40 mEq/L.
Magnesium Balance
-More than half of magnesium ions are free, circulating ions; others bind to albumin and other substances

-Magnesiums levels r/t albumin levels. Low magnesium = low albumin; high magnesium levels = high albumin

-
Systems that regulate magnesium levels
- GI and urinary systems

-Through dietary intake and output in urine and feces

-If serum magnesium levels drop, the GI tract may absorb more magnesium, and excrete more if the level rises

-The kidneys alter its reabsorption at the proximal tubule and loop of henle
Hypomagnesemia
< 1.5 mEq/L
-common among critically ill patients
Hypomagnesemia results from:
- poor dietary intake of magnesium

-poor GI absorption

-increased loss from GI or urinary tract
Hypomagnesemia occurs in patients who:
- are pregnant
-have chronic diarrhea
-hemodialysis
-hypercalcemia
-hypothermia
-sepsis
-burns
-wound debridement
-taking certain medications
Danger signs of low magnesium levels:
* suspect your pt is really in trouble if he has any of these late-developing danger signs or symptoms:
-cardiac arrhythmias
-digoxin toxicity (anorexia, arrhythmias, N/V, yellow-tinged vision)
-laryngeal stridor
-respiratory muscle weakness
-seizures
At r/f Hypomagnesemia:
-alcoholics: poor diet, poor intestinal absorption or from frequent or prolonged vomiting
-pts who can't take magnesium orally: pts receiving prolonged IV fluid therapy, total parenteral nutrition, or enteral feeding with insufficient magnesium
-Pts with diabetes mellitus: loss due to osmotic diuresis
Hypomagnesemia through absorption problems:
-Malabsorption syndromes: steatorrhea, ulcerative colitis, Chron's disease

-cancer, pancreatic insufficiency, excessive calcium or phosphorus in the GI tract
Hypomagnesemia from GI problems
-fluids in the GI tract contain magnesium. This is why when a person has prolonged diarrhea or fistula drainage, can be deficient.

-Pt who uses laxatives or has a nasogastric tube connected to suction is also at risk

In acute pancreatitis, magnesium forms soaps with fatty acids. This takes some of the magnesium out of circulation
Hypomagnesemia from Urinary problems:
-primary aldosteronism
-hyperparathyroidism, hypoparathyroidism
-DKA
-diuretics
-impaired renal absorption of magnesium resulting from disease
Other causes of Hypomagnesemia
-excessive fluid loss
-hypercalcemia
-hypothermia
-SIADH
-sepsis
-serious burns
-wounds requiring debridement
-any condition predisposing them to excessive calcium or sodium in urine
What to look for with Hypomagnesemia:
- CNS, neuromuscular, cardiovascular, and GI

-may resemble potassium or calcium imbalance sx
Hypomagnesemia and CNS
-altered LOC
-ataxia
-confusion
-delusions
-depression
-emotional lability
-hallucinations
-insomnia
-psychosis
-seizures
-vertigo
Hypomagnesia and muscles
-The body compensates for low magnesium, but moving it out of cells
-This causes skeletal muscles to grow weak and nerves and muscles to become hyperirritable
The 3 T's with hypomagnesia:
1. Tremors
2. Twitching
3. Tetany
Hypomagnesemia and hypocalcemia
-if you suspect low magnesium, look for signs of low calcium:
-Chvostek's sign: facial twitching when facial nerve is tapped
-Trousseau's sign: carpal spasm when the upper arm is compressed
Hypomagesemia and the heart
-magnesium promotes cardiac function, so low magnesium can irritate the myocardium
-this can lead to cardiac arrhythmias, low CO
-atrial fibrilation
-heart block
-paroxysmal atrial tachycardia, premature ventricular contractions
-supraventricular tachycardia
-torsades de pointes
-ventricular fibrillation
ventricular tachycardia
ECG changes with low magnesium:
-prolonged PR interval
-widened QRS complex
-prolonged QT interval
-depressed ST segment
-broad, flattened T wave
-prominent U wave
s/sx of hypomagnesemia
-Altered LOC
-Ataxia
-Confusion
-depression
-seizures
-vertigo
-skeletal muscle weakness
-Hyperactive DTRs
-Tetany
-Chvostek's and Trousseau's signs
-Arrhythmias
-rapid HR
-vomiting

*** Remember S.T.A.R.V.E.D
Seizures, Tetany, Anorexia and arrhythmias, Rapid heart rate, Vomiting, Emotional lability, Dtr increased
Tx for hypomanesemia
-change in diet

-oral or IV magnesium replacement
Nursing Interventions Hypomagnesemia
-assess mental status and report changes
-check for hyperactive DTRs, tremors, tetany, (Chvostek's and Trousseau's signs if hypocalcemia is also suspected)
-check for dysphagia before giving food or oral meds
-monitor resp. stats bc hypomagnesemia can cause laryngeal stridor
-cardiac monitoring if magnesium< 1 mEq/L
-monitor pts who have lost an excess of fluid
-monitor urine output at least q4h; magnesium isnt administered if output < 100 ml in 4 hours
-assess VS q15 minutes on a pt with hypomagnesemia
-notify physician if calcium or potassium is low since that can cause hypomagnesemia
-institute seizure and safety precautions
Hypermagnesemia
>2.5 mEq/L

-usually uncommon except in patients with renal failure (especially patients taking antacids or laxatives)
Hypermagnesemia cause by:
-advancing age, which tends to reduce renal function

-renal failure

-Addison's disease

-adrenocortical insufficiency

-untreated DKA
People at risk for Hypermagnesemia
-elderly
-patients with renal insufficiency or failure
-pregnant women in pre-term labor or pregnancy induced htn
-neonates whose mothers received magnesium sulfate during labor
-high intake of magnesium
-adrenal iinsufficiency
-severe DKA
-dehydrated pts
-those with hyperthyroidism
Hypermagnesemia may result from:
-increased intake of magnesium, usually from hemodialysis using magnesium-rich dialysate, TPN with excess magnesium, or continuous magnesium sulfate infusion to treat certain conditions
s/sx of hypermagnesemia:
-decreased muscle and nerve activity
-hypoactive DTRs
-generalized weakness, drowsiness, and lethargy
-facial parasthesia
-N/V
-slow, shallow, depressed respirations
-respiratory arrest (slow, shallow, depressed respirations are indicators of
-ECG changes
-vasodilation
-arrhythmias
Dx tests with Hypomagnesemia:
-serum magnesium level > 1.8 mEq/L
-below normal serum potassium or calcium level
-characteristic ECG changes
-elevated levels of digoxin in pt receiving the drug
Hypermagnesemia Tx
-oral or IV fluids

-avoidance of magnesium products

-calcium gluconate, in emergent situations

-hemodialysis with magnesium-free dialysate (for dialysis patients)

-Mechnical ventilation (for severe cases in which respiration depression is present)
Nursing Interventions for Hypermagnesemia
-monitor VS frequently. Stay alert for signs of hypotension and resp depression
-check for flushed skin and diaphoresis
-assess DTRs and muscle strength
-monitor for hypocalcemia since that can accompany hypermagnesemia, bc low serum calcium level suppresses PTH secretion
-monitor urine output
-evaluate for changes in neuro status
-prepare for continuous cardiac monitoring
-be prepared for emergency ventilation
-prepare for dialysis if tx isnt working
-establish IV access
-restrict magnesium intake
Magnesium is an important electrolyte because it:
-assists in neuromuscular transmission

-acts as a myoneural junction and is vital to nerve and muscle activity
Your pt with Crohn's disease develops tremors while receiving TPN. Suspecting she might have hypomagnesemia, you assess her neuromuscular system. You should expect to see:
-hyperactive DTRs

-In a pt with hypomagnesemia, expect to see hyperactive DTRs because hypomagnesemia increases neuromuscular excitability
When teaching your pt with hypomagnesemia about proper diet, you should recommend
-seafood

-as well as chocolate, dry beans and peas, meat, nuts, whole grains, and green leafy vegetables
Your pt is diagnosed with hypermagnesemia. To treat this imbalance, the practitioner is likely to order:
-Both oral and IV fluids

-By causing diuresis, the fluids promote excretion of excess magnesium by the kidneys
Your hemodialysis patient needs a laxative. When you see that the practitioner has ordered magnesium citrate, you decide to question this order bc:
-magnesium administration could worsen the pts conditon

-Magnesium citrate is a poor laxative choice for a pt with renal impairment whose kidneys can't excrete magnesium properly. The pt could develop hypermagnesemia.
THIS SET IS OFTEN IN FOLDERS WITH...