2. • Magnesium is the fourth most abundant
cation.
• Magnesium balance is maintained by renal
regulation of magnesium reabsorption.
• Magnesium deficiency and
hypomagnesaemia can result from a variety of
causes including gastrointestinal and renal
losses.
3. • Magnesium deficiency can cause a wide
variety of features including hypocalcaemia,
hypokalaemia and cardiac and neurological
manifestations.
• Chronic low magnesium state has been
associated with a number of chronic diseases
including diabetes, hypertension, coronary
heart disease, and osteoporosis
4. • Hypermagnesaemia is less frequent than
hypomagnesaemia and results from failure of
excretion or increased intake.
• Hypermagnesaemia can lead to hypotension
and other cardiovascular effects as well as
neuromuscular manifestations
6. • Plasma magnesium concentration/magnesium status
• Glomerular filtration rate
• Volume status
• Hormones
• PTH
• Calcitonin
• Antidiuretic hormone
• Glucagon
• Insulin
• Phosphate depletion
• Acid base status
• Hypercalcaemia
• Diuretics
• Miscellaneous factors
Factors affecting tubular reabsorption of magnesium
7. Tests used in assessing magnesium
status
Serum Magnesium Concentration
Total magnesium
Ultrafiltrable magnesium
Ionised magnesium
Intracellular Magnesium content
Red cells
Mononuclear blood cells
Skeletal muscle
Physiological tests
Metabolic balance studies
24 h urinary excretion of magnesium
Magnesium loading test
Intracellular free magnesium ion concentration
Fluorescent dye
Nuclear magnetic resonance spectroscopy
8. Magnesium Deficiency and Hypomagnesaemia
• Hypomagnesaemia is frequently undetected.
• In patients with other electrolyte
abnormalities hypomagnesaemia is more
frequent, 40% in hypokalaemic patients, 30%
in hypophosphataemic patients, 23% in
hyponatraemic patients and 22–32% in
hypocalcaemia patients
9. Aetiology and pathogenesis
Redistribution of magnesium
Refeeding and insulin therapy
Correction of acidosis
Massive blood transfusion
Gastrointestinal causes
Reduced intake
Mg free intravenous fluids
Dietary deficiency
low oxalate diet
Reduced absorption
Malabsorption syndrome
Chronic diarrhoea
Intestinal resection
Renal loss
Reduced sodium reabsorption
Saline infusion
Diuretics
Renal disease
Post renal transplantation
Dialysis
Diuretic phase of acute renal failure
Endocrine causes
Hypercalcaemia
Hyperthyroidism
Hyperaldosteronism
Diabetes mellitus
Alcoholism
Drugs
11. Management
• Manage hypoventilation and respiratory
depression.
• ECG monitoring
• Monitor K+and Ca 2+ levels
• IV MgSO4 oral also can be used.
• Mg rich foods-whole grains,meat sea food
green leafy vegetables
12. Hypermagnesemia
• ECF Mg level> 2.5mEq/L
ETIOLOGY
Less common
Underlying chronic renal diasease
abnormla retension- renal failure,adrenal
insufficiency,and Rx with Mg salts
13. Pathopohysiology
• occurs as a result of decreased GFR
• May occur with laxatives compromised renal
function
Clinical manifestation
• Peripheral vasodilation
• nausea,vomiting,paralysis
• hypotension
• decreased DTRs
• Resp depression,C arrest also
14. Management
• treat underlying cause
• Ca Gluconate/ salts antagonizes Mg reverses
cardiac manifestations
• IV hydration for renal clearance
• dialysis may be indicated.
• monitor vitals , LOC
15. PHOSPHATE IMBALANCE
• In the body, almost all phosphorus is combined
with oxygen to form phosphate. Phosphate is
used as a building block for many substances
such as DNA, cell membranes, etc.
• The body obtains phosphate from food and
excretes it in urine and sometimes stool.
• Foods that are phosphate rich are milk, egg yolks,
chocolate and soft drinks. Imbalances in
phosphate may be too high
(Hyperphosphatemia) or too low
(Hypophosphatemia).
16. • Hypophosphatemia is a short-term or chronic
condition that happens when you have a low
level of phosphate in your blood.
• While mild hypophosphatemia is somewhat
common and usually isn’t a cause for concern,
severe hypophosphatemia can be life-
threatening and requires medical treatment.
17. • MAINLY IN BONES REST IN ECF
• ALSO FOUND IN TEETH SOFT TISSUES
• NORMAL LEVEL 2.5-4.5MG/DL
18. HYPOPHOSPHATEMIA
• LEVEL BELOW 3 MG/DL
• BELOW 1 MG/DL IS LIFE THREATENING
ETIOLOGY
LIMTED INTAKE
SHIFT INTO ICF
REDUCED ABSORPTION FROM GI TRACT
INCREASED RENAL ECRETION
19. PATHOPHYSIOLOGY
LIMITED INATKE R/T VOMITING, LONG TERM STARVATION
CELLULAR SHIFT DURING RAPID GROWTH,, HYPERMTABOLIC
STATE
EXCESSIVE USE OF ANTACIDS BINDING OCCURS
MALABSORPTION- IN CROHN’S DISEASE
HEMOLYTIC ANEMIA- ATP DEFICIENCY ( MAINTAIN RED CELL
MEMBRANE)
CLINICAL MANIFESTATION
IRRITABILITY, DISORIENTATION, TREMORS,
SEIZURES, RESPIRATORY FAILURE
POTENTIAL COMA
