Hypomagnesemia
From Anvita Health Wiki
Contents |
More Specific Terms
Etiology
-
- hypoparathyroidism
- hyperaldosteronism
- diabetes mellitus via glucose-induced osmotic diuresis
- disorders of calcium metabolism
- resistance to effects of PTH ( pseudohypoparathyroidism)
- hungry bone syndrome
- malabsorption of Mg+2 in the ileum
- celiac sprue, stearrhea
- pancreatitis [1]
- radiation injury to the bowel
- bowel resection
- small bowel bypass
- excessive GI secretions
- redistribution from extracellular to intracellular space
- 'hungry bone' syndrome after parathyroidectomy
- osteoblastic metastases
- acute respiratory alkalosis
- insulin therapy
- inappropriate renal excretion (decreased tubular reabsorption)
- Bartter's syndrome
- idiopathic magnesium wasting
- obstructive uropathy
- renal transplantation
- chronic interstitial renal disease
- chronic poor nutritional status
- alcoholism
- recovery from acute renal failure
- pharmaceutical agents
- diuretics, thiazides, loop diuretics
- cisplatin
- amphotericin B
- cyclosporine A
- aminoglycoside antibiotics
- pentamidine (rare)
- foscarnet (rare)
- extracellular volume expansion
- cirrhosis
- intravenous ( IV) fluid administration
- genetic disorders (see OMIM correlations)
Epidemiology
- up to 65% of patients in intensive care units
Genetics
Clinical-manifestations
- complaints related to hypomagnesemia are nonspecific
- most patients asymptomatic
- usually, patients become symptomatic at 1.8 mEq/L [2]
- tachycardia
- CNS manifestations
- altered mental status in severe cases
- neuromuscular abnormalities
- positive Chvostek's sign
- positive Trousseau's sign
- convulsions
- muscle weakness, muscle cramping
- dysarthria & dysphagia from esophageal dysmotility Laboratories
- serum Mg+2, serum Ca+2, serum K+, serum phosphorus
- hypokalemia is common
- hypocalcemia is common
- hypophosphatemia may occur
- BUN & serum creatinine
- blood glucose
- inappropriately normal or low PTH
- 24 hour urine magnesium
- > 20-50% retention of IV magnesium sulfate 2.4 mg/kg suggests Mg+2 depletion
- urine Mg+ secretion of > 24 mg/day suggest renal Mg+2
Diagnostic-procedures
- findings are non-specific
- ST segment depression
- tall, peaked T waves
- flat T waves or depression in the precordium
- U waves; loss of voltage
- PR prolongation
- widened QRS
- due to hypomagnesemia alone or concomitant hypokalemia
- paroxysmal atrial & ventricular dysrhythmias
- repolarization alternans
Management
- intravenous magnesium sulfate 1-2 g IV every 6 hours to a total dose of 8-12 g for serum Mg+2 < 1 mg/dL
- oral replacement with magnesium citrate, magnesium oxide, magnesium gluconate
- hypokalemia & hypocalcemia may correct with Mg+2 replacement
- treat seizures with benzodiazepines
More General Terms
Additional Terms
- Chvostek's sign
- magnesium (Mg+2) in serum
- magnesium sulfate (MgSO4)
- pseudohypoparathyroidism
- Trousseau's sign
Internet Database
OMIM: 154020
OMIM: 248250
OMIM: 602014
References
- Medical Knowledge Self Assessment Program (MKSAP) 11, 14, American College of Physicians, Philadelphia 1998, 2006
- eMedicine: hypomagnesemia [1]
