Case presentation: We discovered that the 18-year-old female patient, who has no specific medical history, had autoimmune SOX-1 antibody encephalitis after she experienced two episodes of generalized tonic-clonic seizures. The patient improves with our treatment.

Discussion and concussion: Neural emergency is status epilepticus. Given the significant morbidity of NCSE and the morbidity of SE in general, it is imperative to identify and diagnose its primary etiology. The etiologies of NCSE include illnesses that are structural, metabolic, inflammatory, infectious, toxic, genetic, or cryptogenic. This is the first instance where the etiology of NCSE has been identified as anti-SOX1 auto-antibody positive encephalitis. Thus, it prompts us to speculate that anti-SOX1 antibodies might be a contributing component to NCSE.

Introduction : Seizure is the clinical manifestation of transient excessive or synchronous electrical discharge of brain which can be convulsive or non-convulsive(1). Non-convulsive seizures frequently go unrecognized, even by specialists, since lacks overt motor manifestations. So, they may progress to non-convulsive Status epilepticus (NCSE). Status epilepticus is a neurological emergency leading to prolonged or repetitive seizures that causes severe health-care costs, morbidity, and mortality if left untreated(2). Benzodiazepines are commonly used as first line and they can be used in the prehospital setting. In order to find out potentially treatable causes of SE, The diagnostic work-up should begin as soon as possible along with initial treatment(3)Although most etiologies are recognized after the first evaluation, the detection of more unusual causes may become challenging in selected cases.

We report a case of anti-Sry-like high mobility group box 1 (SOX-1) antibody-positive PNS that manifested with NCSE for the first time. SOX1 antibody have been reported in various neurological syndromes including paraneoplastic neuropathy and Lambert-Eaton myasthenic syndrome.(4) To the best of our knowledge, it is the first time that autoimmune encephalitis with anti-SOX1 antibodies could develop NCSE. This case suggests that anti-SOX1 antibodies maybe related with NCSE.

Case presentation:

An 18-year-old female patient who has never had a specific medical history complained of having two bouts of generalized tonic-clonic seizures after experiencing dizzy at home for the previous month. They were unaware of the patient's automotor seizure, which manifested as automatism. We were obliged to intubate the patient at the beginning of their hospital stay since they were only able to make eye contact and were in the status phase of a seizure.

The following tests were reviewed for the patient: BUN, Cr, Na, K, Ca, P, Mg, BS, PTT, INR, ESR, CRP, U/A, LDH, CPK, Alb, AST, ALT, ALKP, and Bili. Except for Hb and MCV, every test result for the patient was normal.

Levetiracetam 500 mg BD ampule, sodium valproate 400 mg BD ampule, and a drip of 30 mg IV stat of midazolam were started after the patient's symptoms, which included staring, dialeptic seizures, and auto motor seizures in the form of status, were mostly present. The patient was initially diagnosed with non-convulsive status seizures and was put under anesthesia.

Further tests were performed on the patient, including brain CT scan without contrast, lumbar puncture (LP), and magnetic resonance imaging (MRI) to rule out autoimmune and herpetic encephalitis, as well as a paraneoplastic and malignant panel and echocardiography to rule out endocarditis.

Further tests were requested for the patient, including FANA, Anti-dsDNA, P-ANCA, C-ANCA, Lupus anti-so, and Anti-SOX-1 Antibody, since the patient's overall condition did not improve with the continuance of this treatment. Out of all these panels, only the Anti-SOX-1 Antibody had a positive result at a level of 25, suggesting a malignant and paraneoplastic workup. Sonography, chest x-ray and abdominopelvic CT scan results were normal; no evidence of cancer was detected.

Thus, we continued the patient's pulse of methylprednisolone 500mg IV in 250cc normal saline, IVIG 30gr IV daily for five days, rituximab ampule 1gr in 500cc normal saline, and the anticonvulsant medication concurrently with the diagnosis of autoimmune SOX-1 antibody encephalitis. Following this treatment, the patient's overall health improved, auto motor seizures and associated symptoms subsided, and the patient regained the ability to communicate and obey.

Discussion:

Status epilepticus is a neurological emergency.  It is crucial to recognize NCSE and diagnose main cause of it, given the severe morbidity and morbidity of SE in general. Structural, metabolic, inflammatory, infectious, toxic, genetic or cryptogenic disorders are etiologies of NCSE.(1) The diagnostic evaluation of SE is aimed to identify factors that help treat and improve the prognosis. Initial tests are as follow CBC, electrolyte panel, venous blood gas, glucose, BUN, Cr, Ca, P, Mg, albumin, coagulation, PCR, vitamins (B12, folate, A, E), liver function test, urine analysis, CSF analysis (cell counts, protein, and glucose) and Brain MRI. Then based on suspected entity of SE further assessments would be paraneoplastic and autoimmune encephalitis antibody panel, chest/abdomen/pelvis CT scan, ultrasound of scrotal/abdominal, Pelvic MRI, cytology and flow cytometry of CSF and Serologic tests.(3)

Anti-SOX-1 antibody was reported in 2005 for the first time, named as “anti-glial nuclear antibodies”. it is known to be associated with neurological conditions like Lamberton-Eaton myasthenic syndrome, limbic encephalitis, sensory neuronopathy, and sensorimotor neuropathy.(5) Aside from neuropathy have been reported, our case is the first example of anti-SOX1 as an associated factor of NCSE.

Cho Hee-Jin et al reported a 76-year-old man known case of squamous-cell lung cancer presented Anti-SOX1 antibodies presenting with New-Onset Refractory Status Epilepticus NORSE. They detected Anti-SOX1 antibodies in his serum in further assessments. NORSE has found to be associated with different autoantibodies, especially anti-N-methyl-D-aspartate receptor (NMDA) and anti-voltage-gated potassium channel (VGKC)-complex antibodies but had not been reported previously in a patient with encephalitis with anti-SOX1 antibodies.(6) The limitation of this study would be not testing the titers of autoantibodies in this patient.

Conclusion:

This is first case in which anti-SOX1 auto-antibody positive encephalitis is found as the etiology of NCSE. So, it leads us to hypothesize that anti-SOX1 antibodies may be an associated factor of NCSE.