Cerebellar abscesses caused by dog bite: a case report.

INTRODUCTION: Bites by house pets can be lethal or cause a series of catastrophic events with severe sequels, such as the loss of a limb or a systemic infection which may be life-endangering, especially in the case of children being bitten. PRESENTATION: A 2-year-old girl was attacked by a dog, causing lesions at the occipital region. This was treated initially as a superficial wound that became further complicated with two cerebellar abscesses. These abscesses required neurosurgical and antimicrobial treatment, with a satisfactory outcome. CONCLUSION: The precise and diligent evaluation of a lesion caused by an animal bite may prevent further life-endangering complications. To the best of our knowledge, there are no reports about cerebellar abscess caused by a dog bite. When cranial lesions are penetrating, an abscess must to be considered. We insist on the importance of medical evaluation and adequate treatment of such lesions.

Stereotactically-guided biopsies of brainstem tumors.

INTRODUCTION: More than 10 years ago, the goal of our work had been to obtain a tissue sample of infiltrating lesions of the brainstem that had been diagnosed using computerized axial tomography (CAT). At that time, biopsies were believed to be indispensable when starting treatment of tumors. With time our objectives changed. Biopsies remained necessary, since until 1 year before the writing of this article we had not had the benefits of magnetic resonance imaging (MRI) at our Hospital. We also decided that carrying out sound statistics, confirmed by biopsies, was in itself a good procedure, especially in a country in which, to date, no serial studies of brainstem tumors had been undertaken. METHODS: We analyzed all of the patients diagnosed with posterior fossa tumors between March 1989 and March 2002 at the Hospital Infantil de México Federico Gómez (HIM). A preoperative TAC of the cranium was performed on every patient. Stereotactically-guided biopsies during tomography allowed precise control of penetration. Material obtained was sent to the Department of Pathology for analysis. RESULTS: Fifty patients were diagnosed with infiltrating tumors of the brainstem: 30 cases of low-grade astrocytomas, 13 cases of high-grade astrocytomas, 2 cases of primitive neuroectodermic tumors, 2 cases of rhabdoid tumors, 1 case of ependymoma, and 2 patients had non-specified tumors. The most frequent symptoms and signs were ataxia and disturbances of the cranial nerves. There was no mortality caused by penetration, and follow-up studies of more than 5 years were carried out. DISCUSSION: The results from our series were similar to those in the literature. In our case, follow-up studies were undertaken for longer periods. In the first section of our work, we suggest the need for stereotactic biopsies in order to arrive at a precise diagnosis in environments in which MRI may be unavailable. CONCLUSION: At present, presumptive diagnosis of infiltrating brainstem lesions may be adequately undertaken with imaging methods, such as MRI. However, we believe that a stereotactically-guided biopsy provides an accurate method for diagnosing lesions of the brainstem. In our case, this procedure has been carried out entirely in the tomography room, without any complications of disease or mortality.

Short-term and procedural memory for colours and inferior temporal cortex activity.

Two children (male, 10 years, and female, 13 years one month) with tumours of the inferior temporal (IT) cortex of the brain were studied post-surgically for their abilities to carry out a short-term memory test. This involved: differences in colour, number and shape of small plastic objects; differences in receptacles where these objects should be placed and in ways in which this placement should be done; a procedural task involving differences either in colour or in size of wooden rings employed in the task. Their performances in these tests, and those of patients with tumours of other encephalic areas, were compared with the performances of normal controls. The subjects with IT tumours spent a significantly greater amount of time than normal subjects of their age in carrying out the procedural task involving differences in colour. One of the IT subjects also spent a significantly greater amount of time in the procedural task involving size differences. Other differences in the performances of patients with encephalic tumours and the performances of normal controls were not significant. Results are discussed in relation to findings of colour and size perception and memory localized to the inferior temporal and middle temporal cortices.

Preoperative and postoperative analysis of visual and auditory memory in children with cerebellar tumors.

Motivated by the extensive clinical and experimental evidence that links the cerebellum to cognitive processes, we analyzed the auditory and visual memory of nine children with cerebellar tumors. Five patients had midline lesions and four had cerebellar hemispheric tumors. The patients were tested before and after surgery. One of the patients was also tested at 4 and 24 months after surgery. A third group constituted by four children, siblings of some of the patients, served as control. Statistically significant differences (P < 0.05) were found in the test of auditory memory, in which children with cerebellar tumors made a higher number of errors than their normal counterparts. Surgery performed according standard techniques did not increase significantly the number of errors in any of the tested categories. Location of the tumor (hemispheric vs midline) was not a determinant of the performance of the children. The patient tested up to 2 years after surgery demonstrated a progressive improvement in the performance of visual and auditory memory tasks. Our results provide further evidence that the cerebellum plays a role in the integration of auditory stimuli.