Case presentation
The patient was an elderly man in
his 80s, 148 cm tall, weighing 50.0 kg, who presented to a nearby clinic
with discomfort in the inguinal region. Further investigation led to a
diagnosis of extramammary Paget’s disease, for which surgical excision
under general anesthesia was planned. The patient had a medical history
of hypertension and asymptomatic cerebral infarction and was on aspirin.
He had no significant family history. Electrocardiography revealed
complete right bundle branch block, and blood tests did not show any
notable abnormalities.
Anesthesia induction was performed with propofol 60 mg, fentanyl 100 µg,
remifentanil 0.1 µg/kg/min, and rocuronium 50 mg. Maintenance of
anesthesia was achieved using sevoflurane 1%, remifentanil at a rate of
0.1-0.15 µg/kg/min, and intermittent administration of rocuronium 10 mg.
An 8 mm endotracheal tube was used for intubation. Intraoperatively, the
patient’s hemodynamics and oxygenation were stable without any
significant abnormalities. Brain function monitoring to assess sedation
levels was not performed intraoperatively, was not used to assess
sedation levels. The surgery lasted for 2 hours and 49 minutes. The
surgical procedure was completed uneventfully, following which
administration of anesthesia was discontinued. When the end-tidal
concentration of sevoflurane reached 0.1-0.2%, the patient was
awakened, and eye opening was observed. After confirming the patient’s
consciousness, sugammadex was administered, and extubation was
performed. A few minutes after extubation, the patient’s level of
consciousness was observed to decrease, subsequently reaching a Glasgow
Coma Scale (GCS) score of E1V1M1. His respiratory status remained
stable. Considering the possibility of the effect of residual opioids,
naloxone was administered, but with no change in the level of
consciousness. His body temperature was 37.0 ℃. Prompt blood gas
analysis was performed, which revealed normal pH and electrolyte levels.
There were no signs of hypoglycemia (blood sugar 110mg/dL), and no
specific findings to explain the decrease in consciousness level.
However, due to the emergence of right conjugate eye deviation, further
investigations were conducted to evaluate for an intracranial pathology.
Both head computed tomography and magnetic resonance imaging scans were
performed, but no abnormal findings, such as new brain infarctions or
intracranial hemorrhage, were detected (Figures 1 and 2). Since there
were no respiratory or circulatory abnormalities, re-intubation was not
performed. Preoperative systolic blood pressure was around 120 mmHg, and
intraoperative systolic blood pressure remained at 100-130 mmHg. The
patient was urgently transferred to the
intensive care unit (ICU) for
close observation. Approximately one hour after admission to the ICU,
the patient developed involuntary movements in the left upper limb,
suggestive of a seizure. Based on the assumption of an epileptic
seizure, 5 mg of diazepam was administered, which resulted in an
improvement in the level of consciousness (GCS E4V5M6). No further
obvious neurological abnormalities were observed. Subsequently,
levetiracetam administration was initiated from the first day after
surgery. Electroencephalography (EEG) performed on the second day after
surgery showed minimal significant findings. No seizures occurred
thereafter, and the patient was discharged on the 16th day after surgery
without any neurological complications.