A 31-year-old female patient was admitted to our emergency room (ER) with a generalized tonic-clonic seizure. A fever, meaningless movements, restlessness, and self-talk complaints had started a week ago in her medical history. She had a history of surgery for ovarian teratoma 10 years ago. There was no history of drug use. Two polymerase chain reaction (PCR) tests for novel coronavirus disease-2019 performed within the last week were negative. During the initial neurological examination in our ER, she was in the postictal period; her general condition was moderate, her consciousness was drowsy, and cooperation was limited. There was no neck stiffness, pupils equally round, and reactive to light. There was not any facial asymmetry. Examination of other cranial nerves was normal. Spontaneous motor movements were observed in all extremities. Plantar reflexes were flexor bilaterally. Vital findings were stable.
Electrocardiography was regular with normal sinus rhythm. There was not any gross abnormality in hemogram and serum biochemistry tests. Lactate level was slightly elevated to 1.74 mmol/L (0.5-1.6 mmol/L). Brain computerized tomography (CT), magnetic resonance imaging (MRI), and MRI-venography were normal (Fig. 1).
There was not any sign of pneumonia on thorax CT. Due to recurrent seizures despite intravenous diazepam infusions in our ER, phenytoin infusion was introduced. A partial reduction in frequency and duration of the seizures were obtained after phenytoin infusion. Then, she was hospitalized in our intensive care unit. Intravenous phenytoin was maintained with the dosage of 100 mg t.i.d.
Electroencephalogram (EEG) revealed a generalized slow background activity with low voltage that was observed throughout the whole trace without any accompanying epileptiform discharge. Delta waves were observed in the left frontotemporal and central areas (Fig. 2).
During her follow-up, dexmedetomidine infusion was started to decrease her agitation. Opening pressure (17 cm H2O) was normal during the lumbar puncture. Leukocyte count was 10/mm3, erythrocyte count was 10/mm3, and protein level was 29 mg/dl in cerebrospinal fluid (CSF). Prophylactic ceftriaxone (2x2 g), vancomycin (2x1 g), and acyclovir (3x750 mg) were started upon the recommendations of our infectious disease department. Haloperidol and chlorpromazine treatments were initiated after psychiatry consultation requested for the consideration of her persistent agitation. Lorazepam was added during the follow-up. Extensive panel tests for meningitis were negative. CSF-PCR for tuberculosis, Gram's stain of sputum, acid-fast bacilli scan, venereal disease research laboratory-rapid, plasma reagin, treponema pallidum hemagglutination, Rose Bengal test for Brucella results were all negative. Serum ammonia level (77.7 micromol/L) was normal. Upon the persistence of her agitation, mirtazapine and quetiapine were added.
Autoimmune encephalitis panel assessed with immunofluorescence assay revealed NMDAR receptor antibodies in CSF. Intravenous immunoglobulins (IVIG) were administered as 25 g per day. After IVIG therapy for 5 days, her seizures were ceased. She was conscious and partially cooperative at the end of the 2nd week and was discharged. During the outpatient clinic follow-up at the end of 6 weeks, the patient did not report any recurrent seizures, and her neurological examination was completely normal. Rituximab treatment was introduced for long-term immunomodulation.