Recurrent Transient Hypoxemia in a Schizophrenic Patient Caused by Upper Airway Foreign Body Obstruction by Watermelon.

A woman in her 70s with schizophrenia experienced repeated episodes of limb tremors and hypoxemia. Even after admission, the same symptoms continued while in a supine position. However, her condition rapidly improved with bag valve mask ventilation. Although computed tomography suggested aspiration pneumonia, she had a strong cough reflex while performing bronchoscopy, and no residues were observed in the trachea. Following the bronchoscopy examination, the patient was prompted by a nurse and subsequently expelled a mass of watermelon from her oral cavity, which was identified as a watermelon eaten during breakfast on the day. She was diagnosed with aspiration pneumonia, and treatment with 2 g/day of cefotiam was initiated. The inflammatory response had improved, and she was transferred to another hospital for adjustment of psychiatric medications on the 10th day of admission. A study indicated that 77% of emergency medical staff experienced misdiagnosis or delayed diagnosis of patients with mental illnesses. In the present case, various biases and system factors were found to be involved in the diagnostic error. It is crucial to recognize the potential for diagnostic errors in managing patients with schizophrenia given the various biases that may come into play. Furthermore, patients with schizophrenia are at high risk of upper airway foreign body obstruction because of dysphagia or drug-induced effects. When transient hypoxemia is observed, a prompt assessment of the visible intraoral region and, if necessary, evaluation of the entire upper airway through imaging studies should be considered.