As physicians, we have the unpleasant task of learning the differential diagnosis for the diseases we treat. Patients don’t understand it, I have unpleasant memories of using it during rounds as an intern, but this exercise can be helpful for patient care and will keep us out of trouble! Not everything that wheezes is asthma–what are some danger signals that I
might want to modify my original diagnosis of asthma?
Asthma invariably causes symptoms during exercise. If your patient has no symptoms (pre-treatment) during exercise, rethink your asthma diagnosis. How about wheezing at night? Same story…no nocturnal symptoms, not likely to be asthma. Finally, response to therapy is a good clue if co-morbidity is contributing to persistent symptoms. For instance, I prescribe combination therapy (LABA/ICS), yet no improvement in wheezing. Only the most severe asthma patient will not respond to this treatment & I’d start down the path of an alternative diagnosis.
So what is the list for differential diagnosis of wheezing, coughing and suspected asthma? I’ll include links where I have some level of expertise :)
1. Left ventricular failure, mitral stenosis–I love cardiology consults! Pedal edema with dyspnea is a red flag even if they’re in your office for “asthma.”
2. Bronchiectasis, cystic fibrosis. Sweat chloride or genetic testing will suffice for CF, but bronchiectasis is often missed during the evaluation for asthma. High resolution CT of chest is the study of choice….
3. Paradoxical vocal cord motion–This one I have to tell you can stump providers even if asthma is present. The best link for this is American Academy of Allergy.
4. GERD or recurrent aspiration
5. Chronic obstructive pulmonary disease (COPD)–don’t forget about the use of Daliresp™ (500mcg/day)
6. α-1 antitrypsin deficiency–Yes this is rare, but treatment is available and diagnosis is as easy as three drops of blood on a postcard!
7. Interstitial lung disease or hypersensitivity pneumonitis–Again, high-resolution CT of chest is very helpful in this scenario…it’s worth fighting insurance to get the study approved.
8. Allergic Bronchopulmonary Aspergillosis (ABPA)–These are usually patients dependent on corticosteroids to breathe. Check total IgE & with ABPA, values are usually >1,000.
9. Pulmonary embolism–usually shows up in the ER, but you never know.
10. Laryngotracheomalacia–If you cough more when upset or crying with a “barky” cough, think tracheomalacia. Usually present before one year of age. Stridor may not always be present. This video is quite informative.
11. Airway neoplasm, foreign body. Found a peanut, found a peanut…..unilateral wheezing is always a concern here. Must keep a high index of suspicion even if there is no history of choking.
12. Rhinosinusitis–Even if it is asthma, sinusitis is ALWAYS a trigger for asthma flares. Don’t bother with plain sinus x-rays…false negative rate can be as high as 30-40%.
13. Churg-Strauss vasculitis or Hyper-Eosinophilic Syndrome–I won’t say more, just go to the link.