2. Case report
A 43-year-old, otherwise healthy woman visited our emergency room with high fever and a sore throat. She was discharged initially after symptom control, but after three days re-visited with an altered, drowsy mental status (Glasgow coma scale, 4). The body temperature was 38℃. The initial laboratory tests showed mild leukocytosis with slightly elevated C-reactive protein. A lumbar puncture was performed and cerebrospinal fluid (CSF) analysis showed minimal pleocytosis (white blood cells, 3cells/mm3) with slightly elevated protein concentration of 46 mg/dL. The brain MRI (T2-weighted and fluid-attenuated inversion recovery) displayed diffuse swelling in the bilateral cerebral regions involving the bilateral pons (Fig. 1). We immediately administered intravenous (IV) ceftriaxone, vancomycin, acyclovir, and dexamethasone. On hospital day 3, IV immunoglobulin was also administered since autoimmune encephalitis such as NMDA encephalitis could not be ruled out. On hospital day 4, the patient’s mental status recovered, but diplopia remained. The specific serological IgM test via EIA (DIESSE Diagnostica, Italy) for M .pneumoniae was positive (1.5 [cutoff value: 0.9]) and that for IgG was negative. The antibiotics regimen was changed to clarithromycin due to infection with M . pneumoniae . Routine CSF gram stain and bacterial cultures, and polymerase chain reaction tests (PCR) showed negative results for herpes simplex, varicella zoster, cytomegalovirus, Epstein-Barr virus, and Mycobacterium. The tests for autoimmune antibodies (anti-NMDAR, -LGI1, -CASPR2, -AMPA1, -AMPA2, -GABAB-R, -Hu, -Yo, -Ri, -Ma2, -CV2/CRMP5, and -amphiphysin) in the CSF and serum were negative. Also, serum anti GQ1b, GM1 and GD1b IgM antibodies were negative. On hospital day 10, serum IgM value for M. pneumoniae increased by up to 2.1-and the IgG test still was negative. After one month, the patient fully recovered from the neurological deficits and a follow-up brain MRI was completely improved.
Written informed consent was obtained from the patient for publication of the case and any accompanying images.