Hyponatremia

Definition

Hyponatremia is a serum sodium less than 135 mEq/L. Severity ranges from mild to life-threatening depending on rapidity of development and neurologic symptoms.

Causes

• SIADH (too much ADH, water retention)
• Heart failure, cirrhosis, nephrotic syndrome (dilutional)
• GI losses (vomiting, diarrhea)
• Diuretics (thiazides)
• Psychogenic polydipsia
• Addison's disease

Signs and Symptoms

Nausea, headache, muscle cramps, confusion, lethargy, SEIZURES, coma. Neurologic symptoms arise from brain swelling.

Nursing Interventions

• Mild/asymptomatic: fluid restriction
• Severe/symptomatic: hypertonic 3% NS IV, slowly (increase less than 10 mEq/L/24 hours) to prevent osmotic demyelination syndrome (central pontine myelinolysis)
• Treat underlying cause
• Seizure precautions
• For SIADH: fluid restriction, possibly vaptans (conivaptan)

NCLEX Relevance

Priority: seizure precautions. Slow correction to prevent CPM.