Thunderclap Headache Caused by an Inadvertent Epidural Puncture During Oxygen-ozone Therapy for Patient with Cervical Disc Herniation

To the Editor: A 54‐year‐old woman with no significant history of a headache or hypertension underwent epidural oxygen‐ozone injection at a concentration of 30 μg/ml (3 ml) for cervical disc herniation at cervical vertebra (C6–C7) level. Throughout the procedure, the routine monitorings of blood pressure, heart rate, and blood oxygen saturation were performed. One minute following the end of the injection, the patient developed a high‐intensity headache mimicking symptoms of a ruptured cerebral aneurysm. The patient described the location of a headache as present in the frontoparietal and occipital areas accompanied by nausea and vomiting. The presumptive diagnosis of inadvertent epidural puncture was made. The patient was immediately treated oxygen therapy and bed rest. Monitoring showed vital signs of blood pressure (149/83 mmHg), heart rate (86 beats/min), pulse oxygen saturation (SpO2, 96%), blood sugar (6.3 mmol/L), and body temperature (36.6°C). Subsequently, metoclopramide 10 mg and midazolam 1 mg were injected intravenously. Thirty minutes later, the severe headache symptom significantly improved. An immediate brain computed tomography (CT) scan revealed a large air collection in the frontal horns of the lateral ventricles, and a smaller one in the third ventricle region [Figure 1a]. The patient was discharged from the pain treatment clinic after 4 h of observation with a blood pressure of 130/80 mmHg. There were no further symptoms in the following 2 months, and the brain CT scan revealed no significant abnormalities 1 month later [Figure 1b].