Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 48, Num. 2, 2002, pp. 158-159

Journal of Postgraduate Medicine, Vol. 48, Issue 2, 2002 pp. 158-159

Letter to the Editor

Transient Cerebellar Mutism After Posterior Fossa Surgery

Arslantas A, Erhan C, Emre E*, Esref T

Department of Neurosurgery and Nuclear Medicine,* The University of Osmangazi, Eskisehir, Turkey. E-mail: aarslanta@yahoo.com

Code Number: jp02054

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.

The aetiology of transient cerebellar mutism is still unclear. This entity was first defined by Rekate and Yonemasu in 1985.^1,2 Mutism is the total loss of ability to speak without any symptoms related to aphasia and without loss of consciousness. It is seen in up to 8.2% of children operated due to posterior fossa tumour³ and usually arises several days after surgery (mean 1.7 days) lasting for 4 days to 4 months (mean 6.8 weeks).⁴ Reports have demonstrated the occurrence of a focal dysfunction of cerebral perfusion in children with cerebellar mutism after posterior fossa surgery.⁵ Otherwise, Pollack reported that there is no correlation between the size of the tumour and length of vermian incision and the possibility of development of mutism.⁶ Based on the available studies, the most possible reason of transient cerebellar mutism in the present situation may be hypoperfu-sion of cerebrum or cerebellum. Further studies need to be carried out for the explanation of aetiology.

Arslantas A, Erhan C, Emre E*, Esref T

Department of Neurosurgery and Nuclear Medicine,*
The University of Osmangazi, Eskisehir, Turkey.
E-mail: aarslanta@yahoo.com

References

1. Rekate HL, Grubb RL, Aram DM, Hahn JF, Ratcheson RA. Muteness of cerebellar origin. Arch Neurol 1985;43:697-8.
2. Yonemasu Y. Cerebellar mutism and speech disturbance as a comlication of posterior fossa surgery in children. 13^th Annu Meeting Japanese Soc Ped Neurosurg Tsukuba 1985.
3. Dailey A, Mc Khann GM 2nd, Berger MS. The pathophysiology of oral pharyngealapraxia and mutism following posterior fossa tumor resectioninchildren. J Neurosurg 1995;83:467-75.
4. Ersahin Y, Mutluer S, Ça­gli S, Duman Y. Cerebellar mutism: report of seven cases and review of the literature. Neurosurgery 1996;38:60-5.
5. Germano A, Baldari S, Caruso G, Caffo M, Montemagno G, Cardia E, et al. Reversible cerebral perfusion alterations in children with transient mutism after posterior fossa surgery. Child Nerv Syst 1998;4:114-9.
6. Pollack IF, Polinko P, Albright A, Towbin R, Fitz C. Mutism and pseudobulbar symptoms after resection of posterior fossa tumors in children: incidence and pathophysiology. Neurosurgery 1995;37:885-93.

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