Differential Diagnosis for M.J.'s Asthma
- Single most likely diagnosis
- Neutrophilic asthma: This is the most likely phenotype given M.J.'s high sputum neutrophil count (50%) and the absence of elevated eosinophils, FeNO, or IgE levels, which are markers more commonly associated with allergic or eosinophilic asthma. Neutrophilic asthma is often associated with a more severe phenotype and can be triggered by various factors, including respiratory infections and exposure to irritants like tobacco smoke, which aligns with M.J.'s history of exacerbations.
- Other Likely diagnoses
- Late onset-eosinophilic asthma: Although M.J.'s blood eosinophil count is not elevated, and her FeNO is relatively low, late-onset asthma can sometimes present with eosinophilic inflammation that is not always captured by these measures. However, the lack of significant eosinophilia and normal IgE levels makes this less likely compared to neutrophilic asthma.
- Paucigranulocytic asthma: This phenotype is characterized by the absence of significant eosinophilia or neutrophilia. Given M.J.'s elevated sputum neutrophils, this diagnosis seems less fitting, but the variability in inflammatory markers over time and the influence of current treatments could potentially align with this phenotype in some contexts.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Allergic asthma with a different allergen: Although M.J.'s IgE is low, and there's no clear history of allergies, it's crucial not to miss allergic asthma, especially since her most recent exacerbation was after exposure to a smoking environment, which could also be a trigger for allergic reactions in sensitive individuals. However, the lack of elevated IgE and specific allergy history makes this less likely.
- Rare diagnoses
- Other rare forms of asthma: These could include aspirin-exacerbated respiratory disease (AERD), which is often associated with eosinophilic inflammation, or asthma associated with specific occupational exposures. Given the information provided, these are less likely but should be considered if M.J.'s asthma remains poorly controlled or if new exposures are identified.