Hyponatremia can occur with hypovolemia, euvolemia, or hypervolemia depending on the balance of sodium and water in the body. With hypovolemia, sodium loss exceeds water loss leading to volume depletion; common causes include diuretic use, adrenal insufficiency, vomiting, and burns. Euvolemic hyponatremia results from excess water intake relative to normal sodium levels, such as from overhydration in athletes or inappropriate antidiuretic hormone secretion. Hypervolemic hyponatremia occurs when too much water is retained relative to sodium, as seen in heart failure, liver disease, or kidney disease. Symptoms include weakness, headache

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.