A Rare Case of Reversible Splenial Lesion Syndrome with Extracallosal Lesions in the Setting of Deep Anemia

A 35-year-old female patient was admitted to our emergency department with impairment of consciousness, and somnolence. It was learned that the patient had been suffering from headache and anorexia over the last week. The clinic had begun abruptly, and the patient deteriorated over the last 5 hours before admission. The other medical history was unremarkable, and the patient had no history of recent drug use or an infection. The vital signs at admission to the emergency service were within normal limits. The neurological examination revealed that the patient was nonoriented and mildly cooperative. She could not cooperate properly with the examination and an increase in motor and psychological activity was apparent that was compatible with agitation. Other investigations including motor, sensory, and cerebellar tests were roughly within normal limits. The Kernig's and Brudzinski's signs were negative. The laboratory investigations revealed severe iron deficiency anemia (hemoglobin [Hb]: 5.3 mg/dL, serum ferritin: 30 μg/L), mild hyponatremia (131 mM/L [136–146 mM/L]), hyperkalemia (5.1 mM/L), neutrophilic leukocytosis (neutrophil: 89%), and increment of C-reactive protein (27.9 [0–0.8]). The results of the other investigations including liver-kidney functions, thyroid functions, vitamin B12, and folic acid were within normal limits. The initial cranial magnetic resonance imaging (MRI), performed on the 9th hour of the clinic, was normal ([Fig. 1]). Lumbar puncture investigations revealed normal cerebrospinal fluid (CSF) biochemistry, microscopic examination, and the result of the CSF culture was negative. The infectious disease specialist did not consider an infectious etiology of the central nervous system to explain the clinic. Routine electroencephalogram showed mild slow background activity (7 Hz) without discharge and focal slow activity. At this point, the MRI was repeated the day after, which showed restricted diffusion in the splenium, bilateral corona radiata, and left hippocampus ([Fig. 1]). Two-unit red blood cell (RBC) transfusion was administered for deep anemia (the follow-up test revealed Hb level of 8.3 mg/dL and Na level of 134 mM/L) and methylprednisolone 1 g intravenous treatment was initiated considering a possible underlying limbic encephalitis or autoimmune encephalitis. However, after the RBC transfusion, a marked and rapid clinical improvement was achieved, and the patient completely recovered after 2 days, and methylprednisolone was stopped at the second day of therapy. She was fully oriented and cooperative, and the Glasgow Coma Scale was evaluated as 15 points. The results of the screening tests for tumors including computed tomography (CT) thorax, CT abdomen, and pelvic ultrasound were unremarkable. Besides, the tumor markers were within normal limits. The anti-NMDAR antibody, anti-AMPA1 antibody, anti-AMPA2 antibody, CASPR2 antibody, GABARB1/B2 antibody, and LGI1 antibody tests results were negative. The follow-up MRI, performed 1 week later, showed total resolution of the diffusion-restricted lesions ([Fig. 2]). The retrospective analyses of the results, in light of the related literature data, revealed the diagnosis of reversible splenial lesion syndrome (RESLES).