Differential Diagnosis for Vomiting and Fever in a 3-year-old

Single Most Likely Diagnosis

• Viral Gastroenteritis: This is the most common cause of vomiting and fever in children, often due to rotavirus, norovirus, or adenovirus. The symptoms typically include diarrhea, vomiting, fever, and abdominal cramps.

Other Likely Diagnoses

• Urinary Tract Infection (UTI): Young children, especially girls, can present with vomiting and fever as primary symptoms of a UTI. Other signs may include dysuria, frequency, and abdominal pain.
• Pneumonia: Lower respiratory infections can cause fever and vomiting, especially if the child has a severe cough or difficulty breathing.
• Otitis Media: Ear infections are common in young children and can cause fever, vomiting, and ear pain.
• Food Poisoning: Consuming contaminated food can lead to vomiting and fever, often accompanied by diarrhea and abdominal cramps.

Do Not Miss Diagnoses

• Appendicitis: Although less common in very young children, appendicitis can present with vomiting, fever, and abdominal pain. It's crucial to consider this diagnosis to avoid missing a potential surgical emergency.
• Meningitis: This is an infection of the membranes surrounding the brain and spinal cord. Symptoms can include fever, vomiting, headache, and stiff neck. Early recognition is critical due to the high risk of complications and death.
• Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially cutting off blood flow. It's a medical emergency that can cause vomiting, fever, abdominal pain, and bloody stools.
• Diabetic Ketoacidosis (DKA): Especially in children with undiagnosed diabetes, DKA can present with vomiting, fever, and abdominal pain, along with signs of dehydration and altered mental status.

Rare Diagnoses

• Inborn Errors of Metabolism: Certain metabolic disorders can cause episodes of vomiting and fever, often with other systemic symptoms. These are rare but important to consider in the differential diagnosis.
• Neurological Disorders: Conditions such as brain tumors or hydrocephalus can cause vomiting and fever, among other neurological symptoms.
• Hematological Disorders: Leukemia or lymphoma can present with non-specific symptoms including fever and vomiting, especially if there is associated anemia, thrombocytopenia, or neutropenia.