516 JH Yoon, et al. • Idiopathic isolated hypoglossal nerve palsy A B Fig. 1. (A) The patient’s tongue showed right deviation at first visit. (B) Fifteen days after the first visit, the patient’s tongue showed complete recovery. Fig. 2. Neck magnetic resonance image of coronal T2W1 showed normal features. His medical history included a normal spontaneous vaginal de­ livery at 39 weeks with a birth weight of 3,200 g. He had normal developmental milestones, his medical history was unremarkable, and his family history was non­specific. His vaccination history was complete. He had no recent history of upper respiratory track infection and had no snoring at night. There was no history of surgery or trauma. Upon initial physical examination, his body temperature was 36.2 ℃, heart rate 72 beats/min and blood pressure 120/70 mm Hg. The neurological examination revealed right­sided deviation of his tongue upon protrusion, but cranial nerve function, cerebellar function and upper motor neuron function were non­specific; otherwise, physical exam findings were non­specific. A laboratory investigation, neck computed tomography (CT), brain magnetic resonance imaging Fig. 3. Brain magnetic resonance image of sagittal T1W1 showed normal features. (MRI) and otorhinolaryngology consultation were done. Laboratory evaluations revealed: hemoglobin 13.1 g/dL, hematocrit 37.5%, white blood cell 9,300/mm3, platelets 382,000/mm3, peripheral blood smear non­specific, sodium 139.1 mmol/L, potassium 3.9 mmol/ L, GOT/GPT 27/23 IU/L and blood urea nitrogen/creatinine 10.1/0.6. Epstein­Bare virus (EBV) viral capsid antigen (VCA) immunoglobulin (Ig) M negative, Epstein­Barr virus nuclear antigen positive, EBV VCA IgG positive, Cytomegalovirus (CMV) IgM negative, CMV IgG negative. Neck MRI (Fig. 2) and brain MRI (Fig. 3) findings were normal. The otorhinolaryngology consultation disclosed non­specific anatomical problems and no evidence of inflammation. The working diagnosis was that of idiopathic isolated HNP. The patient was treated with Solumedrol (60 mg/day #3) for 12 days. Fifteen days after symptom onset, the patient completely recovered (Fig. 1B).