What is the differential diagnosis and initial management for a 13-month-old presenting with emesis?

Differential Diagnosis for Emesis in a 13-Month-Old

The differential diagnosis for vomiting in a 13-month-old must prioritize life-threatening causes first, followed by common infectious etiologies, with acute gastroenteritis being the most frequent diagnosis. 1

Life-Threatening Causes (Red Flag Conditions)

Immediate consideration must be given to conditions requiring urgent intervention:

• Intestinal obstruction including intussusception, malrotation with volvulus, and incarcerated hernia (bilious vomiting is a critical warning sign) 1
• Increased intracranial pressure from hydrocephalus, intracranial mass lesions, or shaken baby syndrome 1
• Metabolic emergencies including inborn errors of metabolism, congenital adrenal hypoplasia, and symptomatic hypoglycemia 1
• Infectious emergencies such as sepsis, meningitis, and encephalitis 1
• Obstructive uropathy and severe urinary tract infections 1
• Necrotizing enterocolitis (though more common in neonates, can present in this age group) 1

Common Non-Life-Threatening Causes

After excluding emergencies, consider these frequent etiologies:

• Acute gastroenteritis (the leading cause of acute vomiting in children) 1
• Acute gastritis from viral or other infectious causes 1
• Food protein allergy (cow's milk or soy protein intolerance can mimic gastroesophageal reflux symptoms) 2, 3
• Gastroesophageal reflux disease (though typically presents earlier in infancy) 2
• Urinary tract infection (can present with vomiting as the primary symptom) 1
• Otitis media or other upper respiratory infections 1
• Toxic ingestions (increasingly relevant as mobility increases at this age) 1

Critical Assessment Features

Red flag signs requiring immediate intervention include: bilious or bloody vomiting, altered sensorium, toxic/septic appearance, inconsolable crying, severe dehydration, concern for hypoglycemia, severe wasting, or bent-over posture 1

Hydration Status Assessment

The three most useful clinical predictors of ≥5% dehydration are:

• Abnormal capillary refill time 4
• Abnormal skin turgor 4
• Abnormal respiratory pattern 4

For mild dehydration (3-5% deficit), initiate oral rehydration with 50 mL/kg over 2-4 hours using a solution containing 50-90 mEq/L sodium 2

For moderate dehydration (6-9% deficit), administer 100 mL/kg of oral rehydration solution over 2-4 hours 2

Initial Management Approach

Oral rehydration therapy is equally efficacious as intravenous rehydration for mild to moderate dehydration and should be first-line treatment. 4

When to Use Ondansetron

Ondansetron is specifically indicated when persistent vomiting prevents adequate oral intake, not as routine treatment 2

For children ≥6 months with moderate to severe symptoms preventing oral intake:

• Intramuscular dose: 0.15 mg/kg (maximum 16 mg) 2
• Oral dose: 0.2 mg/kg (maximum 4 mg) 1

Use with caution in children with heart disease due to QT prolongation risk 2

Nutritional Management

• Continue breastfeeding on demand without interruption for breastfed infants 2
• Use lactose-free or reduced-lactose formula immediately after rehydration for formula-fed infants 2
• Consider a 2-4 week trial of extensively hydrolyzed formula if milk protein allergy is suspected 2
• Replace ongoing losses with 10 mL/kg for each liquid stool and 2 mL/kg for each vomiting episode 2

When to Obtain Laboratory Studies

Laboratory investigations are required in any child with:

• Dehydration (to assess electrolytes, renal function, acid-base status) 1
• Any red flag signs (to diagnose surgical or metabolic causes) 1
• Bilious vomiting (requires immediate nasogastric decompression and surgical evaluation) 1

Low serum bicarbonate combined with clinical parameters can help predict dehydration severity, though no single laboratory value is sufficiently accurate to be routinely recommended 4