Dysfunctional breathing mimicking asthma exacerbation with acute hypoxemia: a case report.

Background: Dysfunctional breathing (DB) is characterized by abnormal breathing patterns and is often under-recognized in clinical practice. Although DB is generally regarded to be a functional breathing disorder, its potential to cause clinically significant hypoxemia has not been well documented. Case report: A case involving a 24-year-old woman diagnosed with asthma and other psychiatric comorbidities, who developed acute wheezing and oxygen desaturation during hospitalization, is reported. Despite treatment with systemic corticosteroids, the patient's symptoms did not improve. Careful physical examination revealed wheezing, predominantly over the laryngeal area, and detailed observation of her breathing pattern demonstrated irregular respiration with intermittent breath-holding and alternating hyperventilation. The Nijmegen Questionnaire (NQ) score was below the conventional cut-off for DB, whereas the Breathing Pattern Assessment Tool (BPAT) score indicated DB. By adhering to simple bedside breathing instructions, her oxygen saturation rapidly improved without additional bronchodilator or corticosteroid therapy, and both wheezing and desaturation resolved. Conclusion: This case illustrates that DB can be associated with acute hypoxemia and may mimic asthma exacerbation. Careful observation of breathing patterns and the complementary use of the BPAT and NQ are valuable for accurate diagnosis. Simple breathing instructions may serve as an effective initial intervention, helping to avoid misdiagnosis and unnecessary corticosteroid treatment.