Differential Diagnosis for a 22-year-old Patient with Cough for 9 Days and Oxygen Saturation of 97%
Single Most Likely Diagnosis
- Viral Upper Respiratory Tract Infection (URTI): This is the most likely diagnosis given the patient's age, duration of cough, and high oxygen saturation level. Viral URTIs are common in young adults and typically present with cough, sore throat, and runny nose, but do not usually lead to significant hypoxemia.
Other Likely Diagnoses
- Acute Bronchitis: This condition is characterized by a cough that can last for several weeks, often following a viral infection. The patient's symptoms and normal oxygen saturation are consistent with acute bronchitis.
- Pneumonia (Mild): Although the patient has a high oxygen saturation, mild pneumonia could still be a consideration, especially if the cough is productive or if there are other symptoms like fever or chest pain.
- Allergic Rhinitis: If the patient has allergies, allergic rhinitis could be causing the cough, especially if it's a dry cough and accompanied by other allergic symptoms like sneezing or itchy eyes.
Do Not Miss Diagnoses
- Pulmonary Embolism (PE): Although less likely given the patient's age and lack of significant hypoxemia, PE is a potentially life-threatening condition that must be considered, especially if there are risk factors like recent travel, immobility, or family history of clotting disorders.
- Tuberculosis (TB): TB can present with a chronic cough and is important to consider, especially if the patient has been exposed to someone with TB, has recently traveled to an area with high TB prevalence, or has symptoms like weight loss or night sweats.
Rare Diagnoses
- Cystic Fibrosis: This genetic disorder can cause chronic respiratory infections and cough, but it's rare and typically diagnosed in childhood.
- Interstitial Lung Disease: This category includes a variety of rare conditions that affect the lung tissue, leading to symptoms like cough and shortness of breath. They are less common in young adults without significant exposure history (e.g., to certain chemicals) or systemic diseases.
- Sarcoidosis: An autoimmune disease that can affect the lungs, causing cough and shortness of breath. It's rare and often presents with other systemic symptoms.