A 45-year-old female (height, 155 cm; weight, 48 kg) was admitted to our emergency department due to severe headache and irritability. She had visited a local clinic due to lower back pain radiating to the left thigh 10 days before visiting our hospital after 1,000 bows (kneeling to pray in a Buddhist temple) and received a lumbar nerve root steroid injection consisting of a mixture of 40 mg triamcinolone in 3 cc of 0.5% lidocaine on the left side at the L3–4 level, without screening for vertebral disorders by magnetic resonance imaging (MRI). The patient revisited the same clinic 7 and 2 days before admission to our hospital with newly developed neck stiffness and constant lower back pain, respectively, and was treated with a lumbar trigger point injection of 0.5% lidocaine and physical therapy. She showed no improvement and was transferred to our hospital due to severe headache that improved when lying down and worsened when sitting upright. On admission, she was alert but irritable. Bed rest and fluid therapy was prescribed as conservative treatment before a neurosurgeon considered meningitis combined with previously diagnosed pneumocephalus on a brain computed tomography (CT) scan. The treatment did not lead to improvement. Motor and sensory neurological signs and pupil reflexes were normal, except mild nuchal rigidity. She was diagnosed with systemic inflammatory response syndrome and neutrophilia, with a white cell count of 17,000/µl (reference range, 4,000–10,000/µl), a differential of 90.7% neutrophils and a C-reactive protein level of 12.92 mg/dl. A cerebrospinal fluid (CSF) tap detected a foul smelling pus-like CSF (Fig. 1) with an apyrexial body temperature of 36.0℃. Empirical antibiotics of 1 mg vancomycin, 1 g cefepime, and 500 mg metronidazole were given intravenously (IV). Brain CT scan indicated pneumocephalus, subdural hygroma, and meningitis (Fig. 2). A basal cistern tap was performed to treat the pneumocephalus, and conservative care was initiated. The patient progressed to stupor mental status with loss of the pupillary light reflex on hospital day 2 and was intubated with a ventilator under 5 µg/kg remifentanil and 5 mg midazolam IV sedation. An emergent right external ventricular drain (EVD) was inserted at an initial intracranial pressure (ICP) of 20 cmH₂O to control progression of hydrocephalus (Fig. 3). However, EVD functioning was poor, so the neurosurgeon pulled the EVD and corrected the catheter position with a follow-up brain CT scan (Fig. 4) on hospital day 3. The CSF culture identified Streptococcus parasanguinis. The patient displayed some mental improvement, from stupor to drowsy status, on hospital day 4 but an attempt at weaning from the ventilator to a tracheal piece, and stopping the remifentanil and midazolam sedation, failed. An abdominal CT scan demonstrated a space-occupying lesion left of L3–4, which was suspected to be psoas abscess (Fig. 5). The neurosurgeon drained the retroperitoneal abscess while concurrently inserting a left EVD under general anesthesia on hospital day 5. The retroperitoneal abscess was drained again on hospital day 6. The original left EVD was removed due to lack of functioning and the right EVD was inserted to maintain ICP at 15 cmH₂O. The abscess fluid culture revealed the presence of a few S. parasanguinis. The patient showed signs of improvement but responded irregularly to some simple verbal commands. She showed 4.5/4 mm pupil dilation with no light reflex on hospital day 9. No change in the EVD was detected and an attempt to change the EVD catheter failed due to brain swelling. The CT scan showed increased diffuse brain swelling, so the patient underwent a frontal and parietal bone craniectomy to decrease ICP. She became comatose, and her pupils dilated to 6.6 mm with no light reflex despite the decompressive craniectomy. The EVD catheter failed to drain the CSF and was removed on hospital day 13. Mean systolic blood pressure decreased to 50 mmHg with administration of dopamine. The patient died due to diffuse leptomeningitis on hospital day 19.

Although a multidisciplinary approach is needed for effective pain management, nerve block with a locally injected steroid is commonly used to manage acute and chronic pain, as the steroid acts on the pain mechanism, and many pharmacological adjuvants can be used concurrently to enhance effectiveness. Lumbar nerve root steroid blocks are used to control pain in patients suffering from back and leg pain. While fluoroscopic iodine-based contrast guidance is traditionally used for these interventions, ultrasonography has been increasingly used recently. Fluoroscopy is usually performed to identify the exact location for the injection and to avoid injection into the vasculature or a dural puncture. Improvements in technology have led to better visualization and ease of use, and have decreased the incidence of potential adverse complications, such as injecting into the vasculature, pneumothorax, or injecting intraperitoneally. Unfortunately, some patients continue to experience complications associated with a nerve block, which can be lethal. Infectious complications of a lumbar nerve root block are rarely reported and are usually minor, but can be similar to those encountered after an epidural nerve block, such as an epidural abscess or pneumocephalus with meningitis [1,2]. Various guidelines are available to avoid infections, such as aseptic skin preparation, preventive antibiotics, and careful handling of instruments. However, a CSF infection can occur as a consequence of an unintentional dural puncture during a lumbar nerve steroid injection. Here, we present three key factors that determined the outcome in this case.