What is the treatment for dehydration?

Treatment of Dehydration

The treatment for dehydration should be tailored based on severity, with oral rehydration being first-line for mild to moderate dehydration and intravenous fluids reserved for severe cases or when oral intake is not possible. 1, 2

Assessment of Dehydration Severity

Before initiating treatment, assess the severity of dehydration:

• Mild to Moderate Dehydration:

  • Clinical signs: Dry mucous membranes, decreased skin turgor, decreased urine output
  • Laboratory: Serum osmolality <300 mOsm/kg or calculated osmolarity <295 mmol/L

• Severe Dehydration:

  • Clinical signs: Altered mental status, tachycardia, hypotension, severely decreased skin turgor
  • Laboratory: Serum osmolality >300 mOsm/kg or calculated osmolarity >295 mmol/L
  • Inability to take oral fluids

Treatment Algorithm

1. Mild to Moderate Dehydration

• First-line: Oral Rehydration
  • Encourage increased fluid intake with preferred beverages (tea, coffee, fruit juice, water) 1
  • Use oral rehydration solution (ORS) containing 45-75 mEq/L sodium 2, 3
  • Avoid sports drinks, which have suboptimal salt:sugar ratios 4
  • Continue age-appropriate diet during or immediately after rehydration 2
  • For children, breastfeeding should be continued throughout rehydration 2

2. Severe Dehydration

• Intravenous (IV) Fluids Required When:

  • Serum osmolality >300 mOsm/kg or calculated osmolarity >295 mmol/L 1
  • Patient appears unwell or unable to drink 1
  • Shock, altered mental status present 2

• IV Fluid Protocol:

  • Initial resuscitation: 60-100 mL/kg of 0.9% saline over 2-4 hours to restore circulation 5
  • Once circulation is restored, transition to oral rehydration when possible 1, 5
  • For continued IV needs, fluid selection depends on type of dehydration:
    • Isonatremic: 5% dextrose in 0.45% saline with 20 mEq/L KCl 5
    • Hyponatremic: Alternate 0.9% saline and 0.45% saline in 1:1 ratio with 20 mEq/L KCl 5
    • Hypernatremic: 5% dextrose in 0.2% saline with 20 mEq/L KCl over 2-3 days (slower correction) 5

• Subcutaneous Fluids Option:

  • Can be considered in older adults as an alternative to IV fluids 1
  • Appropriate solutions include half-normal saline-glucose 5%, 40 g/L dextrose with 30 mmol/L NaCl, or similar combinations 1
  • May have fewer adverse effects and lower costs than IV administration 1

3. Special Considerations

• Electrolyte Replacement:

  • Add 20 mEq/L potassium to rehydration solutions once urine output is established 5
  • For severe acidosis, consider physiological doses of bicarbonate to correct pH to 7.25 5

• Medication Considerations:

  • Loperamide may be used for adults with acute diarrhea (4 mg initially, then 2 mg after each loose stool, max 16 mg/day) 2
  • Contraindicated in children under 2 years due to risk of respiratory depression and cardiac adverse reactions 6
  • Caution with loperamide in dehydrated patients due to risk of QT prolongation 6

Monitoring and Follow-up

• Reassess hydration status regularly until corrected 1
• Monitor for signs of improvement or deterioration
• For persistent symptoms beyond 48-72 hours, consider alternative diagnoses 2
• Warning signs requiring immediate attention: severe abdominal pain, distension, ileus, toxic megacolon, or sepsis 2

Common Pitfalls to Avoid

1. Using inappropriate fluids: Sports drinks, juices, and sodas are not suitable replacements for proper ORS, especially in children 2, 4

2. Neglecting electrolyte replacement: Fluid replacement alone without addressing electrolyte imbalances can worsen outcomes 6

3. Delaying IV fluids when indicated: Severe dehydration requires prompt IV rehydration to prevent complications 1, 2

4. Correcting hypernatremic dehydration too rapidly: This can lead to cerebral edema; correction should occur over 2-3 days 5

5. Using antimotility drugs inappropriately: Loperamide is contraindicated in children under 2 years and should be used cautiously in dehydrated patients 2, 6