Electrolye imbalance(Hyponatremia )

[dralaa]

Serum Na+ (135-145 mmol/L)
Serum K+ (3.5-5 mmol/L)

Hyponatremia (<135 mmol/L)
( Evaluation of urinary Na+ (10-20 mmol/L) )

Types :-Hypovolemic hyponatremia
• Urinary Na+ >20 due to renal loss (diuretics, hypoaldosteronism , RTA, renal disease)
• Urinary Na+ <10 due to extrarenal loss (vomiting ,diarrhea ,3rd space loss)

Euvolemic hyponatremia
Causes: cushing, hypothyroidism, drugs and SIADH
• Causes of SIADH:
• Cancer: lung ,pancreas
• Pulmonary lesions: pneumonia, lung abscess, T.B
• C.N.S. disorders: meningitis, encephalitis

Hypervolemic hyponatremia
• Urinary Na+ >20 due to renal failure (ARF,CRF)
• Urinary Na+ <10 due to liver cirrhosis, congestive heart failure
Clinical manifestations :-C.N.S. (brain oedema) : lethargy, apathy, convulsions
Neuromuscular : muscle cramps, anorexia, nausea

Treatment:-• Acute symptoms within 48 hrs of onset
(at more risk to develop brain oedema)
• Chronic : more time to adapt to changes, rapid correction center pontine myelenolysis
• Hypovolemic : Normal saline 0.9 % + fluid restriction
Hypervolemic : hypertonic saline 3 % + diuretic


In general
• Rate of correction : 2 mmol/hr till resolution of symptoms
• 3 % hypertonic saline
• Loop diuretics (frusemide)
• Fluid restriction
• TTT cause

Chronic hyponatremia (SIADH)
• Fluid restriction
• Loop diuretics
• Lithium
• Demeclocyclin
• Vasopressin antagonists

[dralaa]

Types :-
1-hypovolemic hypernatremia
• urinary Na+ >20 due to renal loss(diuretics)
• urinary Na+ <10 due to extra renal loss (Diarrhea or GIT fistula )
2-euvolemic hypernatremia
• Diabetes insipidus
3-hypervolemic hypernatremia
• Conn's syndrome or cushing

Treatment :
• Replacement of ECV with :
0.9% saline if hypovolemic
0.45% saline or dextrose 5 % in H2O

[dralaa]

Causes:-
1. Intracellular shift : insulin, B2 agonist
2. ↓ Total body K+ according to urinary K+
3. >20mmol/L : renal loss (RTA, DKA, Diuretics)
4. <20mmol/L : GIT loss (diarrhea, vomiting)

Clinical manifestations:-
• Cardiac : digitalis toxicity, arrhythmia
• Muscular : cramps, weakness (flaccid para
• GIT : constipation, paralytic ileus

Treatment :-
• Dietary K+ supply
• In life threat ( I.V KCL through central V.)

[dralaa]

Causes :-
1. Extracellular shift: metabolic acidosis, ↓ insulin, beta blockers
2. ↓ Renal excretion: RF, RTA
Clinical manifestations :-• Cardiac : ECG (hyperacute T wave, prolonged PR,QT,QRS), bradycardia,cardiac arrest
• Ascending paralysis (late)
• Fatal if >7.5

Treatment :-• Immediate : (ca gluconate 10 % (slow I.V)
Insulin + glucose
B2 agonist inhalation
• Long acting : frusemide
• ↓Dietary K+
• Dialysis in renal impairmen