Paulson - Magnesium Flashcards
hypermagnesemia definition
Mg > 2.5
hypermagnesemia is rare and usually 2/2
renal failure
causes of hypermagnesemia (4)
oral ingestion
Mg enemas
Mg infusion
renal insufficiency
what do you see when you see hyperkalemia rt Mg infusion
pregnancy → eclampsia/preeclampsia
how does ckd affect magenesium
as ckd worsens → Mg rises
2 meds that cause hypermagnesemia
antacids
laxatives
when is hypermagnesemia symptomatic
Mg > 4
mc sx of hypermagnesemia
neuromuscular toxicity
Mg 4-6
nausea
flushing
ha
lethargy
drowsiness
decreased dtr’s
Mg 6-10 (6)
somnolence
hypocalcemia
absent dtr’s
hypotn
bradycardia
ekg changes
Mg >10
muscle paralysis →
flaccid quadriplegia
apnea
respiratory failure
heart block
cardiac arrest
dx for hypomagnesemia (3)
serum. Mg → separate lab
bmp
ekg
ekg changes associated w. hypermagnesemia (3)
diminished conduction
widened qrs
prolonged pq
tx for hypermagnesemia w. normal renal fxn (2)
stop offending agent
+/- diuretics
pharm for hypermagnesemia
IV calcium gluconate
tx for hypermagnesemia if severe + renal impairment
hd
hypomagnesemia definition
Mg < 1.8
mc causes of hypomagnesemia (3)
chronic diuretics → loop and thiazide
chronic diarrhea
chronic ppi
also hypoparathyroidism, etoh
hypomagnesemia affects
neuro
cardiovascular
neuro sx of hypomagnesemia (3)
tetany → trosseau and chvostek
sz
involuntary movements
ekg changes associated w. moderate hypomagnesemia
QRS widening and peaked T waves
ekg changes associated w. severe hypomagnesemia (3)
prolonged pr interval
qrs widening
diminished t wave
PACs, PVCs
vfib
hypomagnesemia frequently occurs w. what other lyte deficiencies
hypokalemia
hypocalcemia
if hypomagnesemia cause not obvious from hx, order (2)
24 hr urine Mg excretion
OR
random urine → fraction excretion
urine tests can help differentiate
GI vs renal Mg losses
sx of severe hypomagnesemia (3)
tetany
arrhythmias
sz
tx for severe hypomagnesemia
IV Mg sulfate
dosing consideration for IV Mg sulfate
renal dosing → CrCl < 30
tx for asymptomatic/mild hypomagnesemia
oral replacement → MgCl or Mg oxide
major s.e of MgCl or Mg oxide
diarrhea