Hyponatremia Mbbs

1. PATHOPHYSIOLOGY OF
HYPONATREMIA

2. Hyponatremia with hypovolemia
 In this situation there is depletion of sodium and water but
sodium deficit exceeds the water deficit, causing hypovolemia
and hyponatremia.
 The cause of sodium loss is usually apparent and common
examples are:
 renal sodium losses-diuretic therapy, Adrenocortical failure
 gastrointestinal sodium losses- vomiting ,diarrhea
 skin sodium losses- burns

3. HYPONATRAEMIA WITH EUVOLAEMIA
 It occurs when the total amount of water in the body
is increased , but the sodium level remains normal.
 Excess body water may be the result of abnormally
high intake ,either orally or as a result of medically
infused fluids .
 E.g – it may happen with athletes who engage in
intense exercise, and then drink too much water.

4.  it also occur in Malnutrition and Severe
hypothyroidism.
 Water retention also occurs in the SIDAH ( syndrome
of inappropriate secretion of antidiuretic hormone )
 In this condition ,an endogenous source of vasopressin
promotes water retention by the kidney in the
absence of an appropriate physiological stimulus.

5. HYPONATRAEMIA WITH HYPERVOLAEMIA
 It occurs when the body holds on to too much
water, relative to its sodium content.
 E.g – heart failure ,liver disease or kidney disease

6. SYMPTOMS ;-
 Weakness
 Headache
 Nausea and vomiting
 Muscle cramps
 Restlessness or irritability
 Slurred speech
 Confusion

7. SIGNS OF HYPONATREMIA
 signs of volume overload can manifest with
edema and ascites.
 But people with hypovolemic hyponatremia will
often have signs of dehydration from volume loss
including dry mouth, decreased skin elasticity
 In severe cases where sodium levels drop below
120 mEq/L ,seizure and coma may occur along
with acute encephalitis ,brain damage and even
death.