A 45 y/o F with a pmh of gastric bypass surgery presents to the ED for evaluation of copious diarrhea x 3 days. The patient appears weak, dehydrated, and sluggish. During your ED evaluation the patient has an acute onset tonic-colonic seizure. The patient is given ativan and is stabilized. Finger stick is 98mg/dL, labs are drawn, results pending. The patient then proceeds to have another seizure.
What electrolyte abnormality could have contributed to the patient’s epileptic event?
- Defined as Mg < 1.9mg/dL; primarily from renal or gi wasting, inadequate dietary intake
- Symptoms include: confusion, anorexia, n/v, lethargy, weakness, tetany, muscle fasciculations; SEIZURES - usually tonic-colonic with SEVERE hypomagnesemia
- Dx confirmed via lab evaluation; hypokalemia, hypocalcemia and metabolic alkalosis frequently coexist with hypomagnesemia
- Mg levels associated with seizures usually < 1.0mg/dL, have been reported with Mg levels as high as 1.4mg/dL
- Rx with Magnesium salts - IV or PO
- Calcium can be given to reverse signs of Mg tox (diminished reflexes, depressed respiratory rate, urinary retention, hypotension)
FUN FACT - If attempting to replete calcium and potassium in patients, remember to check the Magnesium level! Often it is difficult to correct calcium and potassium w/o also repleting Mg.