In this post I link to and excerpt from the Internet Book Of Critical Care [Link is to the Table of Contents] chapter: Hypomagnesemia, August 15, 2019 by Dr. Josh Farkas.
I’ve reviewed this chapter previously in the blog but as these are just my study notes, so I’m reviewing the chapter again.
Here are direct links that Dr. Farkas has provided us to various sections of his chapter:
CONTENTS
Here are excerpts:
diagnosis
magnesium level
physical examination
- Hyperreflexia
EKG manifestations
- Most common is prolonged QT interval, which may progress to Torsade de Pointes.
- May prolong all intervals (PR, QRS, QT).
- May increase risk of various other arrhythmias (especially atrial fibrillation).
symptoms
cardiac
- Cardiac arrest from Torsade de pointes.
- Atrial fibrillation or atrial flutter
- Frequent premature atrial complexes or premature ventricular complexes
neuromuscular hyperexcitability
- seizure
- delirium, depression, psychosis
- cerebellar dysfunction (ataxia, downbeat nystagmus, slurred speech, tremor)
- paresthesias
- muscle cramps, tremors, fasciculation, hyperreflexia, even tetany
Downbeat nystagmus may be caused by hypomagnesemia, Wernicke’s encephalopathy, or structural brain lesions. Get a CT scan, but also check electrolytes & consider thiamine.
other potential consequences
- Insulin resistance
causes
medications
- Diuretics (except for potassium-sparing diuretics)
- Antibiotics
- Aminoglycosides
- Amphotericin B
- Pentamidine
- Foscarnet
- Cyclosporine & tacrolimus
- Platinum-based chemotherapy
- EGFR receptor blockers (cetuximab, panitumumab, matuzumab)
- Proton pump inhibitors
other electrolyte abnormalities (electrolytic disarray)
- Hypercalcemia
- Hyperphosphatemia
- Metabolic acidosis
renal disease
- Chronic tubulointerstitial disease
- Diuresis after recovery from ATN or renal obstruction
- Administration of Mg-free IV fluid
- Osmotic diuresis (e.g. hyperglycemia)
- Renal tubular acidosis
gastrointestinal disease
- Malabsorption
- Proton pump inhibitors
- Inflammatory bowel disease
- Diarrhea, vomiting, NG suction
- Pancreatitis
- Diarrhea
specific situations
- Chronic alcoholism, protein calorie malnutrition, anorexia
- Diabetes, insulin, refeeding syndrome
- Large volume transfusion of citrated blood products
- Continuous renal replacement therapy (CRRT)
- Ethylene glycol intoxication
- Sepsis
evaluation of cause
investigation
- Check complete panel of electrolytes (including Ca/Mg/Phos).
treatment*
Click the above link for treatment details.
