Hyponatremia
Hyponatremia is defined as relative excess of water in
relation to sodium in the body.
Causes and
Classification:
Increased water
Intake:
Primary Polydipsia
Endocrine Disorders:
Adrenal Insufficiency
Hypothyroidism
Impaired water
excretion
Advanced Renal Failure
Increased Anti diuretic Hormone ADH Release.
Causes Of Increased
ADH Relaese:
Decreased effective
circulating volume:
Volume depletion
Congestive Heart Failure
Cirrhosis
Diuretics Overuse
SIADH : Syndrome Of
inappropriate ADH Secretion
Causes Of SIADH:
Central Nervous System Disorders
Cancer/Tumors : (Ususally small cell lung ca)
Medications and Drugs:
Carbamazepine
Cyclophosphamide
SSRIS : Selective Serotonin Reuptake Inhibitors
Lung Diseases
Postoperative patients.
Increased use of hypotonic fluids postoperatively
Symptoms Of hyponatremia:
These are mainly neurological and occur due to cerebral
oedema caused by movement of water into the brain cells.
Earliest symptoms are nausea,malaise followed by headache.
In severe hyponatremia when serum sodium falls below 115 meq
/ L seizures,coma and respiratory arrest can occur.
Treatment Of Hyponatremia/Key Points
It depends upon th cause of hyponatremia,the severity of symptoms
and plasma concentration of sodium.
Management of Severe Symptomatic Hyponatremia / sodium below
115 meq/L
Sodium should be corrected at rate of 1.5 – 2 meq/L / hour
for the first 3 – 4 hours.
Hypertonic saline should be used in this perios eg 3 %
Normal saline.
Plasma sodium levels should be monitored frequently during
this initial correction.
Sodium levels should not be raised more than 12 meq/L in
first 24 hours.
