Differential Diagnosis for a 73-Year-Old Female with Dry Cough
Single Most Likely Diagnosis
- Asthma or Chronic Obstructive Pulmonary Disease (COPD): Given the patient's age and symptoms of dry cough that causes a tickle in the throat, asthma or COPD are plausible. These conditions are common in the elderly and can present with chronic cough, among other symptoms.
Other Likely Diagnoses
- Gastroesophageal Reflux Disease (GERD): GERD can cause a dry cough, especially if stomach acid refluxes up into the throat, irritating it and causing a tickling sensation.
- Postnasal Drip: Also known as upper airway secretion syndrome, this condition can cause a dry cough due to the dripping of mucus from the back of the nose down into the throat, irritating it.
- Bronchitis: Either acute or chronic bronchitis could be a cause, especially if the patient has been exposed to irritants or has a history of respiratory infections.
Do Not Miss Diagnoses
- Pulmonary Embolism: Although the D-dimer is negative, which makes pulmonary embolism less likely, it's crucial not to miss this diagnosis due to its high mortality rate. A negative D-dimer does not completely rule out pulmonary embolism, especially in patients with a high pre-test probability.
- Lung Cancer: Given the patient's age, lung cancer is a critical diagnosis not to miss. A persistent cough, even if dry, can be an early symptom.
- 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 or has risk factors such as immunocompromised status.
Rare Diagnoses
- Sarcoidosis: This is an autoimmune disease that can affect the lungs and cause cough among other symptoms. It's less common but should be considered if other diagnoses are ruled out.
- Interstitial Lung Disease: A broad category of diseases that affect the tissue and space around the air sacs of the lungs, which can cause a dry cough.
- Vocal Cord Dysfunction: This condition can mimic asthma and cause cough and throat irritation due to abnormal vocal cord movement.