Differential Diagnosis
The patient presents with a 3-4 week history of cough, nasal congestion, and hoarseness that has not improved with doxycycline and prednisone. Given the normal chest X-ray (CXR) and normal vitals, the differential diagnosis can be organized into the following categories:
- Single most likely diagnosis
- Postnasal drip syndrome: This is a common cause of chronic cough and is often associated with nasal congestion and hoarseness. The lack of improvement with antibiotics and steroids suggests a non-infectious, non-inflammatory etiology.
- Other Likely diagnoses
- Acute bronchitis: Although the patient has not improved with doxycycline, acute bronchitis can persist for several weeks and may not respond to antibiotics.
- Gastroesophageal reflux disease (GERD): GERD can cause chronic cough, hoarseness, and nasal congestion due to acid reflux and aspiration.
- Allergic rhinitis: Allergies can cause chronic nasal congestion, cough, and hoarseness, especially if the patient is exposed to allergens.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Lung cancer: Although the CXR is normal, lung cancer can present with chronic cough and hoarseness, especially in older adults or those with a history of smoking.
- Tuberculosis (TB): TB can cause chronic cough, hoarseness, and nasal congestion, and is often diagnosed after other causes have been ruled out.
- Angiotensin-converting enzyme (ACE) inhibitor-induced cough: If the patient is taking an ACE inhibitor, this could be the cause of their chronic cough.
- Rare diagnoses
- Sarcoidosis: This is a rare disease that can cause chronic cough, hoarseness, and nasal congestion due to granulomatous inflammation.
- Relapsing polychondritis: This is a rare autoimmune disease that can cause hoarseness, cough, and nasal congestion due to cartilage inflammation.
- Vocal cord dysfunction: This is a rare condition that can cause hoarseness, cough, and shortness of breath due to abnormal vocal cord movement.