Overview
Definition:
Dehydration is a state of excessive loss of body fluid, leading to a deficit in total body water
In pediatrics, it most commonly results from gastroenteritis with vomiting and diarrhea
Oral Rehydration Therapy (ORT) is the cornerstone of management, utilizing an oral rehydration solution (ORS) to replace fluid and electrolyte losses.
Epidemiology:
Diarrheal diseases are a leading cause of mortality and morbidity in children under five globally, with dehydration being the primary cause of death
In India, a significant proportion of pediatric hospital admissions are related to dehydration secondary to acute gastroenteritis
Rotavirus is a common etiology.
Clinical Significance:
Accurate assessment of dehydration severity is critical for appropriate management and preventing life-threatening complications like hypovolemic shock
ORT is a highly effective, cost-efficient intervention that reduces the need for intravenous fluid resuscitation and hospitalization, significantly improving patient outcomes.
Clinical Presentation
Symptoms:
Decreased urine output, indicated by fewer wet diapers or infrequent urination
Thirst, which may be difficult to assess in infants
Lethargy or irritability
Dry mouth and tongue
Absence of tears when crying
Sunken eyes
Sunken fontanelle (in infants)..
Signs:
Mild dehydration: Appears well, slightly thirsty, moist mucous membranes, normal skin turgor, normal capillary refill (<2 sec)
Moderate dehydration: Appears unwell, thirsty/drinks eagerly, dry mucous membranes, decreased skin turgor (pinch returns slowly), delayed capillary refill (2-3 sec), sunken eyes, sunken anterior fontanelle, normal to slightly decreased blood pressure, slightly increased heart rate
Severe dehydration: Appears very ill, unable to drink or drinks poorly, very dry mucous membranes, poor skin turgor (pinch returns very slowly), prolonged capillary refill (>3 sec), sunken eyes, sunken anterior fontanelle, hypotension, tachycardia, cool extremities, mottled skin, decreased consciousness (lethargy to coma).
Diagnostic Criteria:
Clinical assessment based on physical signs and symptoms is the primary diagnostic tool
WHO guidelines classify dehydration into three categories: no dehydration, some dehydration (mild), and severe dehydration, based on the presence of specific clinical signs
The CARE (C-A-R-E) mnemonic is useful: C - Consciousness, A - Arms/Legs (warmth), R - Refill time (capillary), E - Eyes (sunken) and T - Thirst
In India, similar clinical grading systems are employed.
Diagnostic Approach
History Taking:
Quantify fluid loss: Frequency and volume of vomiting and diarrhea
Presence of blood in stool
Fluid intake: What has the child been drinking? How much? How often? Urine output: Number of wet diapers or voiding episodes in the last 24 hours
Duration of illness
Associated symptoms: Fever, respiratory symptoms, other medical conditions
Red flags: High fever, bloody diarrhea, severe abdominal pain, decreased consciousness, inability to keep any fluids down.
Physical Examination:
General appearance: Alert, irritable, lethargic, comatose
Vital signs: Heart rate, respiratory rate, blood pressure, temperature
Assess mucous membranes: Dryness of tongue and oral mucosa
Skin turgor: Pinch the skin over the abdomen or forearm
observe how quickly it returns to normal
Capillary refill time: Press on the sternum or forehead and note the time for color to return
Assess fontanelle: Sunken or full
Assess eyes: Sunken or normal
Assess extremities: Warmth and color.
Investigations:
Generally not required for mild to moderate dehydration due to gastroenteritis
If severe dehydration or atypical presentation: Serum electrolytes (Na+, K+, Cl-, HCO3-), BUN, creatinine to assess renal function and electrolyte imbalances
Blood gas analysis (venous or arterial) to assess acid-base status (metabolic acidosis)
Blood glucose (especially in neonates and infants)
Stool examination: Microscopy, culture, and sensitivity if bloody diarrhea or prolonged symptoms
Serum lactate if hypoperfusion is suspected.
Differential Diagnosis:
Other causes of shock in children: Septic shock, cardiogenic shock, anaphylactic shock
Other causes of vomiting and diarrhea: Food poisoning, parasitic infections, surgical abdomen (intussusception, appendicitis), metabolic disorders, urinary tract infections, pneumonia (especially in infants)
Non-gastrointestinal causes of fever and lethargy.
Management
Initial Management:
For severe dehydration: Immediate intravenous fluid resuscitation with isotonic crystalloids (e.g., 0.9% NaCl or Ringer's Lactate) at a rate of 20 ml/kg bolus, repeated as needed based on clinical response
Simultaneously, start ORT if the child can tolerate oral intake
For moderate dehydration: Aggressive ORT
For mild dehydration: Continue usual diet plus ORS.
Oral Rehydration Therapy:
Components of ORS: Sodium (75 mmol/L), Glucose (13.5 g/L or 75 mmol/L), Potassium (20 mmol/L), Citrate (10 mmol/L), Chloride (65 mmol/L)
WHO-standard ORS is recommended
Administration: Start with small, frequent sips (e.g., 5-10 ml) using a spoon or syringe every few minutes
Increase volume gradually as tolerated
For children: 50-100 ml/kg over 4 hours for mild dehydration
100-200 ml/kg over 4 hours for moderate dehydration, divided into small, frequent amounts
For severe dehydration: Rehydrate intravenously first, then switch to ORT once stable and able to tolerate oral intake
Continue breastfeeding or usual milk feeds
Encourage other fluids like rice water or clear soups if available and tolerated.
Maintenance Fluids:
Once initial rehydration is complete (usually within 4-24 hours), calculate daily fluid requirements and replace ongoing losses from diarrhea and vomiting
For children weighing <10 kg: 100 ml/kg/day
For children weighing 10-20 kg: 1000 ml + 50 ml/kg for each kg >10 kg
For children weighing >20 kg: 1500 ml + 20 ml/kg for each kg >20 kg
Replace ongoing losses: For each episode of diarrhea, give 10 ml/kg of ORS
For each episode of vomiting, may need to pause feeding for 10 minutes and then resume ORT slowly.
Supportive Care:
Monitor fluid balance closely: urine output, stool frequency and volume, vomiting episodes, oral intake
Monitor vital signs
Monitor for signs of worsening dehydration or fluid overload
Continue breastfeeding or formula feeds
Introduce bland solid foods as tolerated once vomiting subsides
Antimicrobial therapy is generally not indicated for viral gastroenteritis but may be considered for specific bacterial or parasitic infections based on stool studies.
Age Specific Dosing:
Infants < 6 months: ORS can be given by spoon/syringe
Breastfeeding should be continued
Avoid giving plain water, as it can lead to hyponatremia
For formula-fed infants, continue formula and supplement with ORS
Older children: Encourage them to drink from a cup or bottle
If vomiting is severe, nasogastric (NG) tube rehydration may be considered for continuous or intermittent ORS infusion, which is as effective as IV rehydration in moderate dehydration.
Complications
Early Complications:
Hypovolemic shock: Can lead to organ hypoperfusion, multi-organ failure, and death
Electrolyte imbalances: Hyponatremia, hypernatremia, hypokalemia, hyperkalemia, metabolic acidosis
Seizures: Often associated with rapid correction of sodium levels or severe hyponatremia
Cerebral edema: Can occur with overly rapid rehydration, especially in hypernatremic dehydration
Hypoglycemia: Particularly in infants and malnourished children.
Late Complications:
Malnutrition: Persistent diarrhea and poor intake can lead to weight loss and failure to thrive
Nosocomial infections: If hospitalized for prolonged periods.
Prevention Strategies:
Early recognition and prompt initiation of ORT at the first sign of diarrhea or vomiting
Educating parents on home management of diarrhea and when to seek medical attention
Ensuring access to clean water and sanitation to reduce the incidence of gastroenteritis
Rotavirus vaccination
Use of ORS as recommended by WHO and national guidelines.
Prognosis
Factors Affecting Prognosis:
Severity of dehydration at presentation
Promptness and adequacy of treatment
Presence of co-morbidities (e.g., malnutrition, pneumonia, sepsis)
Development of complications
Age of the child.
Outcomes:
With timely and appropriate management, including effective ORT, the prognosis for dehydration due to gastroenteritis is generally excellent
Mortality rates are significantly reduced
Children can recover fully without long-term sequelae
Severe dehydration with delayed treatment carries a higher risk of morbidity and mortality.
Follow Up:
Follow-up is typically not required for mild to moderate dehydration managed at home, provided symptoms resolve
For severe dehydration or children with co-morbidities, follow-up may be necessary to ensure adequate nutritional recovery and monitor for any lingering effects
Advise parents on signs of recurrence and when to re-initiate ORT.
Key Points
Exam Focus:
Recognizing the three grades of dehydration (mild, moderate, severe) based on clinical signs
Knowing the WHO ORS composition and administration protocol
Understanding the principles of fluid management: rehydration phase and maintenance phase
Identifying red flags requiring urgent medical attention
Differentiating ORT from IV fluid therapy indications.
Clinical Pearls:
Always assess dehydration severity before initiating treatment
Start ORT aggressively and early
If a child vomits, pause for 10 minutes, then restart ORT slowly
Continue breastfeeding! Breast milk is the best fluid
For hypernatremic dehydration, correct sodium deficit slowly over 48-72 hours to prevent cerebral edema.
Common Mistakes:
Underestimating the severity of dehydration
Delaying ORT or IV fluid resuscitation
Giving hypotonic fluids or plain water instead of ORS
Over-correction of sodium in hypernatremic dehydration
Not replacing ongoing fluid losses adequately
Failing to recognize red flags.