Differential Diagnosis for a 1 Year 11 Month Old Male with Fever, Rhinorrhoea, and Reduced Oral Intake

• Single Most Likely Diagnosis
  • Viral upper respiratory tract infection (URTI): This is the most likely diagnosis given the symptoms of fever, rhinorrhoea, and reduced oral intake, which are common in viral URTIs. The high fever not settled by antipyretics and the presence of emesis also support this diagnosis, as viral infections can cause significant systemic symptoms.
• Other Likely Diagnoses
  • Bacterial pharyngitis: Although less common in this age group, bacterial pharyngitis could present with high fever, reduced oral intake, and systemic symptoms like emesis. The absence of a cough might lean more towards this diagnosis, but the presence of rhinorrhoea makes URTI more likely.
  • Influenza: Given the seasonal variability, influenza could be a consideration, especially with high fever and systemic symptoms. However, the presence of rhinorrhoea and the lack of specific mention of other influenza-like symptoms (e.g., myalgias, cough) make it less likely than a viral URTI.
• Do Not Miss Diagnoses
  • Meningitis: Although the child does not exhibit classic symptoms of meningitis (e.g., neck stiffness, bulging fontanelle, altered consciousness), in young children, meningitis can present with non-specific symptoms such as fever, irritability, and vomiting. The high fever and systemic symptoms warrant consideration of this potentially life-threatening condition.
  • Sepsis: Any child with a high fever, especially one not responding to antipyretics, and signs of systemic illness (reduced oral intake, emesis) should be evaluated for sepsis, particularly if there's a concern for a bacterial source of infection.
  • Pneumonia: Despite the chest being clear on examination, pneumonia should be considered, especially with high fever and respiratory rate. Young children can have pneumonia without classic symptoms or findings on lung exam.
• Rare Diagnoses
  • Kawasaki disease: This condition can present with high fever, although it typically lasts for more than five days and is accompanied by other specific criteria (e.g., rash, conjunctivitis, changes to lips and oral cavity, cervical lymphadenopathy). The acute presentation here makes it less likely but not impossible.
  • Leukemia: Although extremely rare and unlikely given the acute presentation, any child with unexplained fever, especially with systemic symptoms, should have leukemia considered in the differential diagnosis, given its potential severity and the need for early intervention.