Differential Diagnosis
The patient presents with symptoms of a respiratory illness, including nasal congestion, cough, and a slight fever, despite testing negative for RSV, COVID-19, and influenza. The following differential diagnosis is considered:
- Single most likely diagnosis
- Acute Bronchitis: The patient's symptoms, such as cough and nasal congestion, are consistent with acute bronchitis, a common respiratory illness. The improvement in oxygen saturation after administration of dexamethasone also supports this diagnosis.
- Other Likely diagnoses
- Asthma Exacerbation: The patient has a history of inhaler use, suggesting asthma, and the symptoms could be indicative of an exacerbation. The response to dexamethasone also supports this possibility.
- Allergic Rhinitis: The nasal congestion and cough could be symptoms of allergic rhinitis, especially if the patient is exposed to allergens.
- Common Cold: The patient's symptoms are also consistent with a common cold, which is a viral upper respiratory tract infection.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Pneumonia: Although the patient's oxygen saturation improved with dexamethasone, pneumonia is a potentially life-threatening condition that must be considered, especially given the patient's history of hospitalization for RSV/COVID as an infant.
- Pulmonary Embolism: Although less likely, pulmonary embolism is a potentially deadly condition that can present with respiratory symptoms and must be considered, especially if the patient has any risk factors.
- Rare diagnoses
- Cystic Fibrosis: Although the patient has a history of inhaler use, cystic fibrosis is a rare genetic disorder that can present with respiratory symptoms, including cough and nasal congestion.
- Immunodeficiency: The patient's history of hospitalization for RSV/COVID as an infant raises the possibility of an underlying immunodeficiency, which could increase the risk of rare or opportunistic infections.
Treatment Plan
The treatment plan should be guided by the most likely diagnosis, with consideration of the patient's symptoms, medical history, and response to initial treatment. The patient's improvement in oxygen saturation after administration of dexamethasone suggests a beneficial response to corticosteroids. Further treatment may include:
- Continued use of inhaler as needed
- Monitoring of oxygen saturation and respiratory symptoms
- Consideration of additional diagnostic testing, such as a chest X-ray or pulmonary function tests, if symptoms persist or worsen
- Antibiotics if pneumonia is suspected or confirmed
- Referral to a specialist, such as a pulmonologist or allergist, if the diagnosis is unclear or if the patient's symptoms are severe or persistent.