Letter to the Editor - Transient Cerebellar Mutism After Posterior Fossa Surgery

Sir,
A 4-year-old boy presented with a two-month history of headache, intermittent nausea and vomiting. Ataxic gait appeared in last week. He had ataxic gait, bilateral dysdiadochokinesia, dysmetria, horizontal nystagmus, and papilloedema. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) of brain showed a tumour in fourth ventricle and hydrocephalus. Two days after the ventriculo-peritoneal shunt application, suboccipital craniectomy and tumour excision with vermian incision was performed. The patient was operated in the sitting position and there was no peri-operative hypotension. In postoperative period, CT and MRI revealed that the tumour has been removed totally. Three days after the operation, the patient developed mutism, which lasted for three weeks. At the end of the third week the mutism regressed but dysarthric speech continued for two more weeks and then the speech returned to normal. Histopathological diagnosis of tumour was ependymoma. ^99mTC hexamethyl-propyleneamine oxime-single photon emission computed tomographic (SPECT) scan revealed left/right perfusion ratio 0.85 (mutism), 0.99 (post-mutism) in frontal region. This ratio was 0.79 (mutism), 1.06 (post-mutism) in occipital region. In addition to these, perfusion defect area was 0.55 cm³ (mutism), 0.001cm³ (post-mutism) in left frontal region. This area was 0.25cm³ (mutism), 0.04cm³ (post-mutism) in thalamus. Perfusion changes were not observed in cerebellum.