What is known and objective Thrombocytopenia is a common laboratory abnormality among critically ill patients under neurological intensive care unit (NCU) care. Valproic acid (VPA), a widely used antiepileptic drug, is one of the common causes of drug‐induced thrombocytopenia. The purpose of this study was to estimate the incidence and risk factors of thrombocytopenia after intravenous VPA therapy among the patients admitted to NCU. Methods We retrospectively reviewed the medical records of patients who were treated with intravenous VPA during their NCU stay between January 2014 and December 2018. We studied the frequency of thrombocytopenia and further evaluated the risk of thrombocytopenia in these patients. Results Among the 283 patients (181 male [64.0%], mean age: [61.0 ± 14.9] years) who were treated with intravenous VPA, thrombocytopenia was observed in 104 patients (36.7%). Thrombocytopenia was associated with several risk factors, including lower baseline platelet counts (<200 × 109/L); aetiologies other than intracranial or subarachnoid haemorrhage; longer use of VPA (more than 3 days); higher daily dose of VPA (more than 1000 mg/d); concurrent use of VPA with other antiepileptic drugs; infection; and the use of mechanical ventilation. Multivariate analysis found several independent risk factors of thrombocytopenia with intravenous VPA therapy, including lower baseline platelet counts, aetiologies other than intracranial or subarachnoid haemorrhage, use of VPA for more than 3 days and infection. What is new and conclusion Thrombocytopenia is common in NCU patients. Because several clinical and laboratory factors are associated with thrombocytopenia, careful use of VPA should be considered in patients with these risk factors.

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by spontaneous and evoked regional pain. CRPS can be differentiated from other chronic pain conditions by the presence of prominent autonomic and inflammatory changes in the region of pain. The exact pathogenesis of CRPS is still unclear, but there seems to be involvement of multiple peripheral and central mechanisms, including peripheral nerve injury, inflammation, neuronal plasticity, and autonomic dysregulation. The relative contributions of these different mechanisms probably differ from one individual patient to another and even within a patient over time. 1 Although acute CRPS may resolve with conservative medical care, treatment of chronic CRPS is mostly difficult, and there's need for comprehensive multidisciplinary treatment, such as drug treatment, local injection to sympathetic ganglion, spinal cord stimulation, psychological and physical treatment. In intractable CRPS patients, other non-traditional therapeutic approaches such as plasma exchange, medical marijuana, and electroconvulsive therapy (ECT) have been tested. 2 We recently encountered a patient who experienced transient, but complete recovered from CRPS after super refractory status epilepticus. The patient, 55-year-old man was transferred to our hospital with generalized tonic-clonic seizure that lasted for more than 15 minutes. A former construction worker, he became disabled six years ago with multiple fracture in the ribs and the right fibula after falling from a height of three meters. Since the injury, he suffered persistent pain on the back and leg despite the fracture being healed. He described spontaneous, excruciating pain-mainly burning and deep aching-in his back and right lower leg, as well as allodynia and hyperalgesia. A three-phase bone scan showed signs associated with CRPS. He tried several pain treatments, including several opioids, antiepileptic drugs, antidepressants, lumbar epidural block, regional sympathetic nerve blocks, transcutaneous nerve stimulation as well as acupuncture. All these treatments had an insufficient effect. At the time of admission, the patient was comatose, and did not responded to painful stimuli. He was receiving duloxetine 60 mg, pregabalin 600 mg, oxcarbazepine 600 mg, tapentadol 400 mg, clonazepam 4.5 mg, oxycodone 80mg, and trazodone 100 mg. Initial brain MRI including diffusion-weighted image showed no abnormality, but EEG, which was performed at two hours after the admission, showed continuous 2-Hz spike and waves in both frontal areas (Fig. 1), which lasted for three days and terminated with