HYPOMAGNESEMIA IN CRITICALLY ILL MEDICAL PATIENTS

CS Limaye, VA Londhey, MY Nadkar, NE Borges FROM JAPI JAN 2011

MODERATOR-DR. AJEET KR. CHAURASIYA

PRESENTED BY

VINEET MISHRA

Magnesium50% to 60% contained in bone

4TH most common cation in the body

Coenzyme in metabolism of protein and

carbohydrates

Factors that regulate calcium balance appear

to influence magnesium balance

Acts directly on myoneural junction

Important for normal cardiac function

Low serum Mg caused byProlonged fasting or starvation

Shift: Pancreatitis, Insulin administration , Post-

parathyroidectomy

Chronic alcoholism

Fluid loss from gastrointestinal tract

Prolonged parenteral nutrition without

supplementation

Diuretics, aminoglycosides, cisplatinum,

amphotericin

Manifestations

Tremors, tetany , ↑ reflexes, paresthesias of feet

and legs, convulsions

Positive Babinski , Chvostek and Trousseau signs

Personality changes with agitation, depression or

confusion, hallucinations

ECG changes (tall peaked , flat or inverted T

waves ; ST depression , U waves, voltage loss ,

wide QRS and prolonged PR)

SIGNS EXCESS DEFICIENCY

Magnesium (Mg) Hypermagnesaemia

Loss of deep tendon reflexes (DTRs)

Depression of CNS

Depression of neuromuscular function

Hypomagnesaemia

Hyperactive DTRs

CNS changes

BACKGROUNDHypomagnesaemia is an important but

underdiagnosed electrolyte abnormality in critically ill patients.

There are many studies to find the prevalence of hypomagnesaemia and its effects on mortality and morbidity in these patients

Studies have been carried out in intensive care units.

in respiratory intensive care unit critically ill cancer patient

AIMS AND OBJECTIVES

• To study serum magnesium levels in critically ill patients

• To correlate serum magnesium levels with patient outcome.

• To identify the primary medical conditions associated with abnormalities of serum magnesium

• To identify the factors predisposing or contributing to hypomagnesaemia in critically ill patients admitted in a medical intensive care unit

• To detect other electrolyte abnormalities associated with hypomagnesemia

PARAMETERS

Length of stay in MICU

Need for ventilatory support

Duration of ventilatory support

APACHE score

Mortality

METHODOLOGYProspective observational study was carried out in

the Medical Intensive Care Unit(from April 2004 to

May 2005)

Hundred patients admitted to the MICU for critical

illnesses were INCLUDED in the study

Patients who had received magnesium prior to

transfer to MICU were EXCLUDED

Blood sample was collected for estimation of serum

total magnesium levels

History and clinical findings were noted

Hematological, biochemical and radiological

investigations were performed

APACHE score was calculated for each patient on the

day of admission

Serum total magnesium level (1.7 to 2.4 mg/dl) was

determined by colorimetric method using Titan yellow

Normal deviate (z) test was applied for quantitative

data and chi-square test was applied for qualitative

data

CRITICAL DISEASES• Severe infections like

complicated malaria,leptospirosis, tetanus,

urinary tract infections, cellulitis, meningitis,

pneumonia, tuberculosis and mucormycosis.

• Hepatic failure

• Acute renal failure

• Chronic renal failure

• Respiratory failure

Congestive cardiac failure

Cerebrovascular accident

Poisonings including Organophosphate compounds

Snake bite

Acute pancreatitis

Guillain-Barre syndrome

Malignancy

Status epilepticus and

Diabetic ketoacidosis

Mortality

Ventilator need

Ventilator days

MICU stay

APACHE

Hypocalcemia

Hypoalbuminemia

Hypokalemia

Sepsis

DM

Alcoholism

0 10 20 30 40 50 60 70 80 90

Study result

NormoHypo

Representational values

CONCLUSION

HYPOMAGNESEMIA AFFECTED/ASSOCIATED WITH-

HYPOCALCEMIA

HYPOALBUMINEMIA

VENTILATOR NEED

ON VENTILATOR DURATION

SEPSIS

DIABETES MELLITUS

MORTALITY

CONCLUSION CONTD. . . . . HYPOMAGNESEMIA NOT AFFECTED/ASSOCIATED WITH-

MICU STAY

APACHE II SCORE

HYPOKALEMIA

ALCOHOLISM (CHRONIC)

SUMMARYHypomagnesaemia is a common electrolyte

imbalance in the critically ill patients.Whether hypomagnesaemia directly

contributes to cellular alterations leading to increased mortality, morbidity and poor patient outcome in critically ill patients or it is just a marker of critical illness is not clear.

Hypomagnesaemia is associated with higher mortality rate in critically ill patients and is also associated with more frequent and more prolonged ventilatory support.

It was seen in this study that hypomagnesaemia is frequently associated with sepsis and diabetes mellitus.

Although there was a high incidence of hypomagnesaemia in the present study, its correction after magnesium supplementation was not included as a part of the study.

The potential benefit of magnesium supplementation to prevent or correct hypomagnesaemia in critically ill patients requires further study.

MAGNESIUM ESTIMATIONSpecimen: non-hemolyzed serum or lithium heparin

plasma used. EDTA and citrate bind to the Mg.

24hr urine may be used and should be acidified to avoid Ppt.

Colorimetric method/photometric[TITAN YELLOW]: Mg binds to calmagite, formazen dye and methylthymol blue to form a chromogen that is measure at 532- 600nm.

Ca2+ should be eliminated from the sample

AAS- absorbance at 285.2nm

ISE- free Mg with neutral carrier inonophores

TAKE HOME MESSAGE

Hypomagnesaemia is NOT A RARE electrolyte abnormality in critically ill patients.Hypomagnesemia should NOT be misdiagnosed as Hypokalemia.It should be ordered with Na, K and Ca serum levels.REMEMBER HYPOMAGNESEMIA TOO !!