• Home
  • EMCrit-RACC
  • PulmCrit
  • IBCC
  • EMNerd
  • Tox & Hound
  • About
    • About EMCrit
    • About PulmCrit
    • EMCrit FAQ
    • Subscription Options
  • Contact Us

Internet Book of Critical Care (IBCC)

Online Medical Education on Emergency Department (ED) Critical Care, Trauma, and Resuscitation

  • ToC
  • About the IBCC
  • Tweet Us
  • IBCC Podcast
You are here: Home / IBCC / Hypermagnesemia


Hypermagnesemia

August 15, 2019 by Josh Farkas

CONTENTS

  • Diagnosis
  • Causes
  • Evaluation
  • Treatment
  • Podcast
  • Questions & discussion
  • Pitfalls
  • PDF of this chapter (or create customized PDF)

diagnosis

(back to contents)


rough correlation between Mg level and symptoms
physical examination
  • Hyporeflexia
    • Presence of reflexes argues against severe hypermagnesemia.
    • Hyporeflexia is nonspecific, however (e.g. some patients have sluggish reflexes at baseline).
  • Bradycardia, hypotension
EKG findings
  • wide QRS and peaked T-waves (can mimic hyperkalemia)
  • heart block
range of symptoms that may occur
  • Cardiac
    • Hypotension
    • Bradycardia, complete heart block
  • Neurologic
    • Muscular weakness (can progress to respiratory failure from diaphragmatic involvement)
    • Delirium, coma
    • Smooth muscle paralysis:  urinary retention, intestinal ileus, pupillary dilation

causes

(back to contents)


Renal Failure plus:
  • Persistent hypermagnesemia requires renal failure (or, less commonly, and ongoing source of magnesium).
  • However, in addition to renal failure, there is usually another source of magnesium
(1) exogenous magnesium
  • Magnesium infusions for pre-eclampsia
  • Magnesium-containing antacids
  • Magnesium-containing laxatives or enemas
(2) endogenous magnesium from cellular lysis
  • Rhabdomyolysis
  • Hemolysis
  • Tumor lysis syndrome
  • Crush injury, severe burns

evaluation

(back to contents)


investigations
  • If the lab is hemolyzed, repeat it (hemolysis may cause pseudo-hypermagnesemia)
  • Obtain complete set of electrolytes including Ca/Mg/Phos (to evaluate for additional concurrent electrolyte abnormalities).
  • Consider LDH, creatinine kinase, or uric acid (to evaluate for hemolysis, rhabdomyolysis, or tumor lysis).

treatment

(back to contents)


moderate hypermagnesemia (e.g. Mg <10 mg/dL, no cardiac/respiratory symptoms)
  • Volume resuscitation
  • Treatment of underlying cause
  • Furosemide may be considered to enhanced magnesium excretion, but make sure to replace excreted volume to avoid hypovolemia.
severe hypermagnesemia (cardiac and/or respiratory consequences)
  • IV calcium may stabilize myocardium
    • Two grams of calcium gluconate IV over 5-10 minutes (or one gram of calcium chloride).
    • May need to repeat or, in extreme cases, give as a continuous infusion.
  • Elimination
    • Not oliguric:  forced diuresis with furosemide plus saline (with close monitoring of volume status and other electrolyte levels).
    • Oliguric:  emergent dialysis

podcast

(back to contents)


The segment of this podcast about hypermagnesemia begins at 18:30: 

Follow us on iTunes

The Podcast Episode

http://traffic.libsyn.com/ibccpodcast/IBCC_Episode_50_Hyper_and_HypoMagnesium.mp3

Want to Download the Episode?
Right Click Here and Choose Save-As


questions & discussion

(back to contents)


To keep this page small and fast, questions & discussion about this post can be found on another page here.

  • Moderate hypermagnesemia (e.g. Mg 5-8 mg/dL) is generally pretty well tolerated.   Be careful about attributing severe symptoms to this degree of hypermagnesemia.
Going further
  • Hypermagnesemia (WikEM)

The Internet Book of Critical Care is an online textbook written by Josh Farkas (@PulmCrit), an associate professor of Pulmonary and Critical Care Medicine at the University of Vermont.


Who We Are

We are the EMCrit Project, a team of independent medical bloggers and podcasters joined together by our common love of cutting-edge care, iconoclastic ramblings, and FOAM.

Like Us on Facebook

Like Us on Facebook

Subscribe by Email

EMCrit is a trademark of Metasin LLC. Copyright 2009-. This site represents our opinions only. See our full disclaimer, our privacy policy, commenting policy and here for credits and attribution.