Differential Diagnosis for an 11-month-old Infant with Respiratory Symptoms
- Single most likely diagnosis
- Bronchiolitis: This is the most likely diagnosis given the infant's age, history of upper respiratory infection, and symptoms of a tight cough, expiratory wheezing, and scattered expiratory wheezes without stridor. Bronchiolitis is a common lower respiratory tract infection in infants, typically caused by the respiratory syncytial virus (RSV).
- Other Likely diagnoses
- Asthma: Although less likely in an 11-month-old infant without a prior history of asthma, it could be considered, especially if there's a family history of asthma or if the infant has had previous episodes of wheezing.
- Croup: Croup is characterized by a barking cough and stridor, which is not present in this case. However, it's still a consideration in infants with respiratory symptoms.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Foreign Body: Although the history does not suggest an acute onset or a clear incident of foreign body aspiration, it's crucial to consider this diagnosis due to its potential for severe consequences, including airway obstruction.
- Pneumonia: While the chest radiograph is normal, pneumonia should always be considered in cases of respiratory distress, as it can be life-threatening. The absence of fever and a normal chest X-ray make it less likely, but clinical judgment and possibly further evaluation might be necessary.
- Rare diagnoses
- Other viral or bacterial infections: There are numerous other pathogens that could cause respiratory symptoms in an infant, though they are less common or might present with additional symptoms not described in the scenario.
- Anatomical abnormalities: Conditions such as tracheomalacia or vascular rings could cause respiratory symptoms but are less common and typically have other associated findings or a more chronic course.