What is the management of dehydration in different age groups according to Harrison's principles?

Management of Dehydration Across Age Groups

Oral rehydration solution (ORS) is the first-line treatment for mild to moderate dehydration in all age groups, with age-specific dosing and assessment strategies that differ significantly between infants, children, adults, and elderly patients. 1

Initial Assessment by Age Group

Infants and Children (<18 years)

• Assess dehydration severity through physical examination focusing on skin turgor, mucous membrane moisture, mental status, rapid breathing, and signs of hypovolemic shock 1
• Monitor weight changes throughout therapy as the most reliable indicator of rehydration adequacy 1
• Reassess hydration status after 3-4 hours of treatment and adjust therapy based on clinical response 1

Adults

• Carefully assess all adults with acute dehydrating diarrhea to rule out cholera 1
• Evaluate duration of illness, stool characteristics (quantity, frequency, consistency, blood), vomiting frequency, and presence of fever 1

Elderly Patients (≥65 years)

• All older persons should be screened for dehydration when contacting healthcare, when clinical condition changes unexpectedly, and periodically when malnourished 1
• Use directly measured serum or plasma osmolality (>300 mOsm/kg indicates dehydration) as the gold standard diagnostic test 1
• Recognize that degree of frailty and functional status are more relevant than chronological age alone 1

Oral Rehydration Protocol

Infants (<2 years)

• Administer 50-100 mL of ORS after each stool 1, 2
• Continue breastfeeding throughout the illness without interruption 1, 2
• For formula-fed infants, dilute milk with equal volume of clean water until diarrhea stops 1
• For infants unable to drink but not in shock, use nasogastric tube at 15 mL/kg/hour 1, 2

Children (2-18 years)

• Administer 100-200 mL of ORS after each stool 1, 2
• For children >4-6 months, offer freshly prepared foods (cereal with beans or meat, vegetable oil added) every 3-4 hours 1
• Encourage eating as much as tolerated; never delay feeding until diarrhea stops 1

Adults

• Give as much ORS as desired; adults failing to respond promptly require reassessment to exclude cholera 1, 2
• Encourage locally available fluids prepared at home (cereal-based gruels, soup, rice water) 1
• Avoid soft drinks due to high osmolality 1

Elderly Patients

• Encourage small amounts of fluids throughout the day rather than large volumes at once 3
• Ensure minimum intake of 1.7 liters per 24 hours 3
• Make drinks easily available and accessible at all times with frequent reminders 3
• Consider more concentrated hydration sources like soups if difficulty drinking adequate volumes 4

Intravenous Rehydration Indications

All Age Groups

Administer isotonic IV fluids (lactated Ringer's or normal saline) when there is severe dehydration, shock, altered mental status, failure of ORS therapy, or ileus 1, 4

Specific Protocols by Age

Children and Adults:

• Continue IV rehydration until pulse, perfusion, and mental status normalize 1
• Once stabilized, transition remaining deficit replacement to ORS 1

Elderly Patients:

• Initiate 0.45% or 0.9% normal saline at 4-14 mL/kg/hour (approximately 200-700 mL/hour for 50kg patient) 5
• Start at lower end (4-7 mL/kg/hour or 200-350 mL/hour) given high risk of cardiac compromise and fluid overload 5
• Immediately reduce or stop fluids if observing increased jugular venous pressure, pulmonary crackles, peripheral edema, or respiratory distress 5
• Reassess after 3-4 hours and adjust based on clinical response 5

Critical Age-Specific Pitfalls

Infants

• Use nasogastric tube for shock only if IV equipment unavailable 1
• Hypertonic dehydration requires slower rehydration over 48 hours with 1/2 to 1/3 isotonic Ringer-lactate to avoid cerebral edema 6

Elderly

• Avoid overly aggressive resuscitation due to reduced cardiac reserve, impaired renal function, and higher baseline heart failure risk 5
• Clinical signs like skin turgor, sunken eyes, dry mouth, tachycardia, and orthostatic changes have inadequate diagnostic value in elderly 7
• Transition to oral fluids as soon as tolerated with continued 24-hour monitoring 5

Maintenance and Monitoring

All Ages

• Replace ongoing stool losses with ORS until diarrhea and vomiting resolve 1
• Resume age-appropriate diet immediately after rehydration completes 1
• Monitor for adequate hydration: pale yellow urine, urination 4-6 times daily, absence of thirst 4

Antimicrobial Therapy

Antibiotics are contraindicated for routine uncomplicated watery diarrhea; specific indications only include cholera, Shigella dysentery, amoebic dysentery, and acute giardiasis 1