5th January 2024

Differential diagnoses

• Vocal cord dysfunction or paradoxical vocal cord dysfunction – abnormal adduction of vocal cords during inspiration. Vocal cord dysfunction might exist alone or co-exist with asthma. Patients with chronic asthma symptoms, normal spirometry and poor response to asthma medications and frequent evaluations should be assessed for vocal cord dysfunction using direct laryngoscopy either during an exacerbation or post-exercise.
• Tracheal and bronchial lesions- Various airway tumours such as endobronchial carcinoid, tracheal hamartoma, bronchogenic cysts and mucoepidermoid tumours are reported to present similarly to asthma.
• Foreign bodies- aspiration of foreign bodies may cause localised or generalised wheeze. Foreign bodies in peripheral airways cause localised one-sided wheeze or collapse in distal lung tissue.
• Congestive heart failure- lung compliance is reduced secondary to engorged pulmonary vessels and interstitial oedema in congestive heart failure, which will contribute to breathlessness and wheeze.
• Gastroesophageal reflux- GORD is associated with cough, wheeze and may manifest similarly to asthma.
• Sinus disease- chronic sinusitis may present with nocturnal cough and dysnpnea due to post-nasal discharge.
• COPD- COPD and asthma can be differentiated based on history and examination findings such as history of smoking and hyper-resonance to percussion or barrel chest on examination. Chest X-ray in COPD may show hyper-inflation of the lungs. Pulmonary function tests show obstructive pattern, increase in total lung capacity and elevated residual volume. FEV1/Forced vital capacity is <70%.
• Bronchiectasis- severe bronchiectasis presents with recurrent respiratory infections. High-resolution CT of chest will show dilated airways and bronchial wall thickening.
• Other differential diagnoses
  • Aspergillosis
  • Churg-Strauss syndrome
  • Pulmonary eosinophilia

References 

• BMJ Best Practice [Internet]. bestpractice.bmj.com. [cited 2022 Apr 3]. Available from: https://bestpractice.bmj.com/topics/en-gb/44/differentials
• Asthma Differential Diagnoses [Internet]. Medscape.com. 2019. Available from: https://emedicine.medscape.com/article/296301-differential