Description

A 70-year-old woman with a history of panic disorder was admitted to the emergency room for loss of consciousness from carbon dioxide (CO₂) narcosis due to atelectasis following lobectomy for lung cancer. After mechanical ventilation, the carbon dioxide partial pressure (PCO₂) and consciousness levels improved, but she was immobile, showing reduced responsiveness to the environment. While neurological tests for motor function yielded normal results, she did not attempt to move voluntarily. Although her language comprehension was preserved, she did not speak spontaneously. Even though she could breathe, she remained ventilator-dependent. Spontaneous breathing trials induced severe tachypnoea; thus, tracheostomy was performed. Multiple clinical examinations, including blood and cerebrospinal fluid testing and brain imaging, were normal. Electroencephalography showed background slowing. The PCO₂ level remained within normal values during these conditions. Therefore, the cause of her ventilator dependence was unclear. The only neurological abnormality was rapid ‘ping-pong’ eye deviations: an oculomotor disturbance characterised by involuntary, rapid, alternating gaze between right and left (video 1). These movements were pronounced under psychological stress, such as during neurological examination, but they completely disappeared when she was relaxed, for example, when watching television or spending time alone. Based on these findings, she was diagnosed with catatonia and functional saccadic oculomotor disturbance.1 This manifestation gradually disappeared after 2-month liaison psychiatry therapy with antianxiety drugs. Acute catatonia should be suspected when a patient fails to withdraw from mechanical ventilation without evidence of a respiratory deficit. The absence of a neurological abnormality other than an oculomotor disturbance may assist in confirming the diagnosis, especially in patients with a history of psychiatric disorders.2