A 15 year old girl presented to the ER with coma following several tonic–clonic convulsions.\nThe patient was previously healthy with no personal or familial medical history. During her visit to a dentist for endodontic treatment, the dentist injected 1.5 ml of 2 % lidocaine (the total dose was 30 mg) and epinephrine 1:100,000 for local anesthesia. The solution was injected on the left side by an expert hand without prior aspiration.\nThe injection lasted about 2 min. By the end of the injection, the girl collapsed and several intermittent tonic–clonic convulsions ensued. These lasted about 30 min and were followed by deep coma.\nGlasgow coma scale (GCS) was three, brainstem reflexes were intact, and no fever was noticed. Vital signs were within normal limits.\nHer left cheek and gingiva were edematous and a giant gingival hematoma was noticed.\nOptic disc examination showed no edema.\nElectrocardiogram (ECG) was normal except for sinus tachycardia (120 beat per minute).\nElectroencephalography (EEG) showed diffuse slow activity, predominately theta rhythms, with no signs of continuous status epilepticus.\nBrain computed tomography (CT) revealed reduced white–gray matter differentiation with effacement of cerebral sulci which was compatible with cerebral edema.\nBrain magnetic resonance imaging with venogram (Fig. ) and angiogram (Fig. ) MRI + MRV + MRA showed cerebral edema, bilateral and almost symmetric hyperintense T2 lesions with restricted diffusion in both frontal and occipital lobes (Fig. ), and no underlying cerebral venous thrombosis CVT.\nLumbar puncture was performed and revealed the following results: 10 lymphocytes, elevated protein (50 mg/dl), no RBCs, and negative gram stain. Whereas blood glucose was 50 mg/dl, CSF glucose was 70.\nOrdinary labs including Calcium, Albumin, MG, Na, K, creatinine, urea, LFTs, CBC, Plt, PT, PTT, and INR were all normal and troponin was negative.\nThe patient was admitted to the ICU and intubated.\nPhenytoin at dose 15 mg/kg was loaded with close cardiac monitoring, and a maintenance dose of 100 mg twice daily was initiated in the second day.\nA bolus (1 g/kg) of Mannitol was given intravenously, followed by a maintenance dose of 0.5 g/kg/8 h. GCS, consequently, improved to nine in 2 days.\nThe patient recovered completely and was discharged after a week of admission.
Patient 3 was a 71-year-old male with partial tear of the left rotator cuff who received an arthroscopic rotator cuff repair. The patient had an unremarkable medical history. The positioning of the patient applied during surgery was the beach chair position. An ISB combined with TIVA was planned as the anesthetic strategy. Left ISB was performed by injecting a single-dose of 1% lidocaine (20 mL) and 0.75% ropivacaine (20 mL) followed by continuous interscalene infusion of 0.2% ropivacaine at 6–8 mL/h. There was a negative aspiration test for blood and cerebrospinal fluid prior to injection. Advancement and placement of the catheter was performed in PNS technique using a stimulating catheter. Physical examination prior to surgery confirmed an effective interscalene block. Adverse cardiac or neurologic symptoms were not recorded. For the entire duration of surgery, the patient remained hemodynamically stable and the case proceeded uneventfully under general anesthesia. Immediately after termination of TIVA, and extubation in the OR, the patient presented a considerable delay of waking reactions and aphasia, left-sided gaze preference, severe right-sided central facial palsy, and right-sided severe hemiparesis graded as 1/5 according to the MRC scale for muscle strength. These symptoms persisted during postoperative monitoring in the postanesthesia care unit. Brain imaging three to four hours post-surgery did not detect any cerebral lesions.