9.3 Pediatric Diarrheal Diseases & Dehydration

Pediatric Diarrheal Diseases & Dehydration

Diarrheal diseases remain among the leading causes of preventable under-five illness and death in Kenya. Severe dehydration secondary to acute gastroenteritis leads rapidly to hypovolemic shock, metabolic acidosis, acute kidney injury, and electrolyte derangements. The implementation of standardized oral rehydration therapy (ORT), low-osmolarity Oral Rehydration Salts (ORS), universal zinc supplementation, and rapid intravenous fluid resuscitation protocols (IMCI Plans A, B, and C) has revolutionized pediatric diarrheal management.

---

1. Definitions & Clinical Classifications of Diarrhea

Under IMCI and Kenya pediatric guidelines, diarrheal illnesses are categorized into three distinct clinical syndromes:

1. Acute Watery Diarrhea: Passing 3 or more loose or liquid stools within a 24-hour period, lasting for less than 14 days. The primary pathological threat is acute water and electrolyte depletion leading to dehydration.
   • Common Etiologies: Rotavirus (historically the most lethal, now mitigated by routine Rotavirus vaccination at 6 and 10 weeks), Norovirus, Astrovirus, Enterotoxigenic Escherichia coli (ETEC), and Vibrio cholerae (in epidemic settings).
2. Dysentery (Acute Bloody Diarrhea): Diarrhea characterized by visible red blood in the stool, accompanied by fever, abdominal cramps, and tenesmus.
   • Common Etiologies: Shigella species (specifically Shigella flexneri and Shigella dysenteriae type 1), Campylobacter jejuni, Enteroinvasive E. coli (EIEC), and Entamoeba histolytica.
3. Persistent Diarrhea: A diarrheal episode that begins acutely and lasts for 14 consecutive days or longer.
   • Pathophysiology: Extensive blunting and destruction of intestinal villous architecture, brush-border disaccharidase enzyme deficiency (secondary lactose intolerance), progressive nutrient malabsorption, and severe acute malnutrition.

---

2. IMCI Dehydration Assessment Framework

To classify dehydration severity, the clinician systematically examines the child for Four Standardized Physical Signs:

THE FOUR IMCI DEHYDRATION SIGNS:

1. General Appearance / Mental State:
   • Normal/Alert ──► Restless / Irritable ──► Lethargic or Unconscious

2. Eyes:
   • Normal ──► Sunken

3. Fluid Offer (Offer water or ORS by cup):
   • Drinks normally (not thirsty) ──► Thirsty, drinks eagerly ──► Unable to drink or drinks poorly

4. Abdominal Skin Pinch (Pinch skin midway between umbilicus and flank for 1 second):
   • Retracts immediately (<1 sec) ──► Retracts slowly (1–2 sec) ──► Retracts very slowly (>2 sec)

Clinical Pitfall — Severe Malnutrition: In a child with severe acute malnutrition (kwashiorkor or marasmus), standard clinical dehydration signs can be misleading. Subcutaneous fat loss causes skin pinches to retract slowly even when the child is not dehydrated, while sunken eyes are common in marasmus. Conversely, abdominal edema in kwashiorkor can mask true fluid deficits. Over-resuscitation with rapid IV fluids can precipitate fatal heart failure. Always look for lethargy, cold extremities, and weak core pulses, and prioritize oral rehydration with ReSoMal (Rehydration Solution for Malnutrition) rather than rapid IV infusions unless frank hypovolemic shock is present.

---

3. Rehydration Protocols: Plans A, B, and C

Plan A: Home Treatment for Diarrhea (No Dehydration)

Plan A aims to prevent dehydration and malnutrition through four core household rules:

1. Rule 1 — Give Extra Fluids: Encourage the mother to give as much fluid as the child will accept. Recommended fluids include low-osmolarity ORS solution, clear vegetable soups, coconut water, rice water, and clean water. If exclusively breastfed, increase the frequency and duration of breastfeeding. For older children, administer extra ORS after each loose stool:
   • Children under 2 years: 50 to 100 mL of ORS after each loose stool (approximately 500 mL/day).
   • Children 2 years up to 5 years: 100 to 200 mL of ORS after each loose stool (approximately 1,000 mL/day).
2. Rule 2 — Universal Zinc Supplementation: Administer daily zinc for 14 consecutive days.
3. Rule 3 — Continue Feeding: Never withhold food. Continue frequent, energy-dense, easily digestible meals (mashed bananas, potatoes, porridge enriched with milk or oil). Continued feeding prevents nutritional faltering and accelerates enterocyte regeneration.
4. Rule 4 — Know When to Return Immediately: Counsel the mother to bring the child back immediately if the child: becomes unable to drink or breastfeed, develops a high fever, vomits everything, develops blood in the stool, or shows no improvement after 3 days.

Plan B: Oral Rehydration for Some Dehydration (Outpatient Clinic)

Plan B restores existing fluid deficits over a 4-hour observation period in the health facility:

• Target ORS Volume Calculation:

Target Volume (mL) = Child Weight (in kg) × 75 mL

• If the child's exact weight is unknown, use age-based guidelines: <4 months (200–400 mL); 4–11 months (400–700 mL); 12–23 months (700–900 mL); 2–5 years (900–1,400 mL).
• Administration Protocol: Administer the calculated volume slowly and steadily using a clean cup and spoon. If the child vomits, wait 10 minutes, then resume administration more slowly (e.g., 1 spoonful every 2 to 3 minutes). Breastfeeding should continue on demand whenever the child desires.
• Reassessment at 4 Hours:
  • If signs of dehydration have resolved -> transition to Plan A.
  • If Some Dehydration persists -> repeat Plan B for another 4 hours and start offering food.
  • If dehydration has worsened to Severe Dehydration -> immediately transition to Plan C.

Plan C: Rapid Intravenous Rehydration for Severe Dehydration

Severe dehydration is a medical emergency requiring rapid intravenous expansion of the circulating vascular volume:

• Preferred Intravenous Fluid: Ringer's Lactate (Hartmann's Solution). It provides physiological concentrations of sodium (130 mmol/L), potassium (4 mmol/L), chloride (109 mmol/L), and lactate (28 mmol/L), which metabolizes to bicarbonate to correct metabolic acidosis. If Ringer's Lactate is unavailable, 0.9% Normal Saline can be used. Warning: Never use 5% Dextrose in water, as it lacks electrolytes and induces fatal cerebral edema and hyponatremia.
• Total Fluid Volume: 100 mL/kg body weight.
• Age-Stratified Infusion Timetable:

PLAN C INTRAVENOUS RESUSCITATION TIMETABLE (100 mL/kg Total):

┌────────────────────────────────────────┬────────────────────────────────────────┐
│            INFANTS (< 12 Months)       │       CHILDREN (12 Months to 5 Years)  │
│            Total Duration: 6 Hours     │            Total Duration: 3 Hours     │
├────────────────────────────────────────┼────────────────────────────────────────┤
│ Step 1: Rapid Bolus                    │ Step 1: Rapid Bolus                    │
│   • 30 mL/kg over 1 HOUR               │   • 30 mL/kg over 30 MINUTES           │
│                                        │                                        │
│ Step 2: Maintenance Infusion           │ Step 2: Maintenance Infusion           │
│   • 70 mL/kg over 5 HOURS              │   • 70 mL/kg over 2.5 HOURS            │
└────────────────────────────────────────┴────────────────────────────────────────┘

• Continuous Monitoring: Reassess the child every 15 to 30 minutes. If the peripheral radial pulse remains weak, thready, or undetectable after the initial 30 mL/kg, repeat the rapid 30 mL/kg bolus over the same timeframe. Once the child can drink safely without choking (usually after 3–4 hours in infants, or 1–2 hours in older children), administer oral ORS solution at 5 mL/kg/hour alongside the running IV infusion to supply additional potassium and base.

---

4. Universal Zinc Supplementation

Zinc is an essential micronutrient critical for cellular immunity, mucosal epithelial repair, and enzymatic gastrointestinal function. During acute diarrhea, substantial zinc is lost in stool.

Physiological Mechanisms of Zinc

• Accelerates the regeneration of damaged enterocytes and restores brush-border disaccharidases.
• Enhances tight junction integrity, reducing intestinal mucosal permeability.
• Facilitates mucosal water and electrolyte absorption by inhibiting cyclic AMP-induced secretomotor pathways.
• Stimulates local gut cell-mediated immunity and secretory IgA production.

Standard Dosing Protocol (Kenya MOH & WHO)

• Infants under 6 months of age: 10 mg elemental zinc (1/2 dispersible tablet) once daily for 14 consecutive days.
• Children 6 months up to 5 years: 20 mg elemental zinc (1 full dispersible tablet) once daily for 14 consecutive days.
• Clinical Benefits: Universal 14-day zinc administration reduces the duration of the current diarrheal episode by 20–25%, decreases stool frequency and volume, and provides prophylactic protection against recurrent diarrheal episodes for the subsequent 2 to 3 months.

---

5. Management of Dysentery & Persistent Diarrhea

Dysentery (Bloody Diarrhea)

• Any child presenting with visible red blood in loose stools has dysentery. In Kenya, the vast majority of severe pediatric dysentery cases are caused by invasive Shigella.
• Antimicrobial Therapy:
  • First-Line Regimen: Oral Ciprofloxacin (15 mg/kg twice daily for 3 days).
  • Widespread bacterial resistance has rendered historical agents (ampicillin, cotrimoxazole, tetracyclines, and nalidixic acid) ineffective.
• Mandatory 2-Day Review: Reassess the child after 48 hours. Successful therapy manifests as resolution of fever, reduction in stool frequency, and disappearance of blood. If symptoms persist or worsen, switch to second-line therapy (oral Azithromycin or parenteral Ceftriaxone) and investigate for amoebiasis.

Persistent Diarrhea (Diarrhea ≥ 14 Days)

• Severe Persistent Diarrhea (Pink): Diarrhea lasting ≥14 days accompanied by any degree of dehydration (Some or Severe). Requires immediate pre-referral fluid stabilization, screening for systemic sepsis, and urgent hospital admission for specialized dietary therapy.
• Persistent Diarrhea (Yellow): Diarrhea lasting ≥14 days with No Dehydration.
  • Management: Prescribe universal 14-day zinc; prescribe a multivitamin/mineral supplement containing vitamin A, folic acid, iron, and copper for 2 weeks; introduce a low-lactose or lactose-free diet (e.g., fermented milk/yogurt or lactose-free porridge) to counteract mucosal lactase deficiency; schedule clinical review in 5 days.