What is the likely diagnosis for a 14-month-old child presenting with a coarse cough and fever for one week, who is unvaccinated and has a family history of measles exposure, with delayed capillary refill time (CRT) indicating impaired peripheral circulation?

Differential Diagnosis for a 14-Month-Old with Coarse Cough, Fever, and Exposure to Measles

• Single Most Likely Diagnosis
  • Measles: Given the patient's exposure to family members with confirmed measles, lack of vaccination, and symptoms consistent with measles (coarse cough, fever), this diagnosis is highly probable. Measles typically presents with a prodromal phase of fever, cough, and conjunctivitis, followed by a characteristic rash.
• Other Likely Diagnoses
  • Respiratory Syncytial Virus (RSV) infection: RSV is a common cause of respiratory illness in young children, particularly those under 2 years old, and can present with similar symptoms such as cough and fever.
  • Influenza: Although less likely given the specific exposure history, influenza can cause similar symptoms and should be considered, especially during flu season.
  • Pertussis (Whooping Cough): The patient's coarse cough could suggest pertussis, especially in an unvaccinated child, though the absence of a characteristic "whoop" and post-tussive vomiting makes it less likely.
• Do Not Miss Diagnoses
  • Bacterial pneumonia: While less likely given the exposure to measles, bacterial pneumonia is a serious condition that can present with cough and fever. The prolonged capillary refill time (5 seconds) may indicate dehydration or sepsis, making this a critical diagnosis not to miss.
  • Sepsis: The combination of fever, cough, and prolonged capillary refill time raises concern for sepsis, a life-threatening condition requiring immediate intervention.
• Rare Diagnoses
  • Cystic Fibrosis with pulmonary infection: Although rare, cystic fibrosis could present with recurrent or severe respiratory infections. However, this would be an unusual initial presentation without prior suggestive history.
  • Immunodeficiency with opportunistic infection: Given the patient's lack of vaccination and potential for exposure to various pathogens, an underlying immunodeficiency could be considered, especially if the patient fails to respond to typical treatments or has recurrent severe infections.