Nausea and Vomiting (Pediatrics: Learning Outcomes)

1. Define Vomiting

The student can list various types of vomiting, their correlation with age, and the clinical significance/severity of specific presentations (e.g., forceful vs. effortless).

2. Differentiate and explain causes of vomiting by dominant pathophysiological mechanism

I. Physiological and Benign Causes (primarily in infants)

Gastroesophageal Reflux (GER): Frequent "spitting up" (regurgitation); painless, with no failure to thrive.
Overfeeding
Aerophagia (swallowing air)

II. Surgical Causes

Neonates / Infants:
- Hypertrophic Pyloric Stenosis: Typically 3rd–6th week of life; projectile non-bilious vomiting; "hungry vomiter"; leads to hypokalemic hypochloremic alkalosis.
- Intestinal Obstruction: (e.g., atresia, volvulus, intussusception).
  - Atresia: Presents shortly after birth; bilious vomiting.
  - Volvulus: Bilious vomiting, pain, shock.
  - Intussusception: Colicky pain, bloody stools ("currant jelly" stool), vomiting.
Older Children:
- Appendicitis: (especially atypical—may present initially with vomiting).
- Ileus: Other causes (e.g., post-operative adhesions).
- Trauma: (e.g., splenic rupture, duodenal hematoma).

III. Infectious Causes

Gastroenteritis: (Rotavirus, Norovirus, bacterial—Salmonella, Campylobacter, E. coli); the most common cause.
Urinary Tract Infection (UTI): Primarily in infants.
Otitis media, Pharyngitis, Pneumonia: Vomiting as a non-specific sign of infection.
Meningitis / Encephalitis: Vomiting + fever, meningism (meningeal irritation), altered mental status.

IV. Metabolic and Endocrine Causes

Diabetic Ketoacidosis (DKA): Polydipsia, polyuria, abdominal pain, vomiting, acetone breath.
Hyponatremia / Hypernatremia
Inborn Errors of Metabolism (IEM): (e.g., organic acidurias, fatty acid oxidation disorders, urea cycle defects); vomiting, lethargy, hypoglycemia, metabolic acidosis.
Adrenal Insufficiency: (e.g., CAH – Congenital Adrenal Hyperplasia); vomiting, hypoglycemia, hypotension, hyponatremia, hyperkalemia.

V. Neurological Causes

Increased Intracranial Pressure (ICP): (Tumor, hydrocephalus, trauma); vomiting unrelated to meals, no preceding nausea, morning vomiting, headache, bradycardia, altered consciousness (Cushing’s Triad = bradycardia, hypertension, respiratory irregularity).
Neuroinfection
Migraine (Abdominal Migraine): Episodic vomiting without other cause; often a positive family history.
Cyclic Vomiting Syndrome: Episodes of vomiting separated by symptom-free intervals; often stress-related.

VI. Toxic and Pharmacological Causes

Poisoning: (Medications, mushrooms, chemicals).
Adverse Drug Reactions: e.g., antibiotics, chemotherapy.

VII. Psychogenic and Functional Causes (more common in school-age and adolescents)

Eating Disorders: (Anorexia, Bulimia).
Psychosomatics / School Phobia

VIII. Allergic and Immunological Causes

Food Allergy: (e.g., CMPA – Cow's Milk Protein Allergy).
Eosinophilic Esophagitis / Gastritis
Food Protein-Induced Enterocolitis Syndrome (FPIES)

3. Take a medical history and clinical examination for differential diagnosis

Age of the child
Frequency of vomiting and time of day.
Characteristics of vomitus: Bilious (yellow/green) vs. non-bilious; presence of blood (hematemesis).
Associated symptoms: Abdominal pain, fever, neurological signs, altered mental status.

4. Target the physical examination to differentiate causes

I. Assessment of General Status (Priority)

Vital Signs: Temperature, HR (Heart Rate), RR (Respiratory Rate), BP (Blood Pressure), O₂ saturation.
Signs of Dehydration: Dry mucous membranes, capillary refill time (CRT) > 2s, skin turgor, oliguria, sunken anterior fontanelle in infants.
Altered Mental Status: Somnolence, lethargy, irritability (suggests metabolic or CNS causes).

II. Age as a Key Factor

< 1 month: Consider pyloric stenosis, atresia, IEM.
Infants: GER, infection, intussusception.
School-age: Migraine, psychogenic, appendicitis, eating disorders.

III. Abdomen – Palpation, Auscultation, Inspection

Pain: Localization and guarding (defense).
Distension and Peristalsis: (Auscultation).
Specific Findings:
- Pyloric Stenosis: Palpable "olive-shaped" mass in epigastrium, visible peristaltic waves.
- Intussusception: Palpable mass in the right lower quadrant/hypogastrium, colicky pain.
- Appendicitis: Tenderness in the right iliac fossa, Blumberg sign (rebound tenderness).
- Peritonitis / Ileus: Rigid ("board-like") abdomen, diminished or absent bowel sounds.

IV. Neurological Examination

Level of consciousness, fontanelle status in infants (tension, bulging).
Vomiting + Headache + Bradycardia --> Suspected increased ICP.
Nystagmus, Diplopia, Ataxia --> Possible CNS tumor/encephalitis.
Neonate with hypotonia/lethargy --> Consider IEM.

V. ENT / Respiratory Exam

Fever without clear focus - Consider UTI or Meningitis.

VI. Skin Findings

Petechiae, Purpura: Sepsis, Meningococcemia, Henoch–Schönlein purpura (HSP).
Hyperpigmentation of Gums, skin, nipples - Adrenal insufficiency.

5. Utility of Laboratory and Imaging Methods

Vomiting + Dehydration: Electrolytes, ABG (Acid-Base Balance), Urinalysis.
Fever + Vomiting: CRP, CBC (Complete Blood Count), Urinalysis, Blood cultures.
Vomiting + Altered Consciousness / Acetone Breath: Glucose, ketones, lactate, ammonia.
Suspected Pyloric Stenosis: Abdominal Ultrasound (US).
Suspected Intussusception: Ultrasound ("target sign").
CNS cause: CT/MRI, possibly Lumbar Puncture (LP).

6. Initial Therapy and Acute Management Steps

The student knows to always assess vital signs first and stabilize the patient.

IV Access & Rehydration:
- Oral Rehydration Solution (ORS) for mild cases.
- Parenteral Hydration (10–20 ml/kg crystalloid bolus) for moderate to severe dehydration.
Antiemetics: Used with caution based on age (e.g., Ondansetron in older children).
Oxygen and Monitoring: If consciousness is impaired.
Empiric Antibiotics: If sepsis or meningitis is suspected.

Vomiting (paediatrics, learning outcomes)

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