Arterial occlusion in purulent meningitis and multicystic encephalomalacia

Abnormalities of cerebral blood flow in the acute phase of bacterial meningitis in adults

The frequency, course and clinical significance of changes in regional cerebral blood flow (rCBF) during bacterial meningitis were investigated in 14 adult patients. The results of 99mTc-hexamethylpropylene amine oxime (HMPAO) single photon emission computed tomography (SPECT) were compared with the clinical signs and findings using cerebral angiography and conventional CT. HMPAO SPECT was performed 2-15 days (median 4.5 days) after the onset of neurological disease. Decreased HMPAO accumulation was detected in 13 patients. SPECT studies revealed focal hypoperfusion corresponding to the clinical symptoms in 6 patients suffering from hemiparesis or hemiataxia. Conventional cranial CT disclosed brain infarction in only 1 patient. Focal hypoperfusion was also found in 7 of 8 patients without clinical evidence of focal neurological deficits. In 6 patients, HMPAO SPECT findings were abnormal although cerebral angiography was normal. At follow-up examinations 3-45 weeks after the acute disease, abnormalities revealed by HMPAO SPECT had improved or had even disappeared in all patients studied. Our results indicate that reduced rCBF is a frequent finding in bacterial meningitis in the adult. In most patients it probably represents a functional and reversible disorder without structural lesion detectable on CT.

Multicystic encephalopathy--a polyetiologic condition in early infancy: morphologic, pathogenetic and clinical aspects

Eleven observations of severe multicystic encephalopathy ( MCE ) in young infants and in a two-year-old child provide the basis for a summing-up and discussion of the various aspects of this characteristic polyetiologic phenomenon occurring in early infancy. In all cases the triggering causes or underlying disorders were different, although in five cases the common pathogenetic mechanism was a disturbance of circulation and/or respiration (acute respiratory distress syndrome). In two cases the basic disorders were a suppurative and a granulomatous meningoencephalitis. Carbon monoxide poisoning had occurred in one and diffuse meningocerebral angiomatosis in another two cases. In the eleventh case, one of a complicated twin birth, the exact cause of the MCE remained obscure. These cases together with those recorded in the literature demonstrate that the surprisingly constant pattern of damage in MCE , which results from different etiologic conditions, should be due to a specific mode of reaction of the infantile brain to a common pathogenetic mechanism. Anoxia with hypercapnia and the formation of brain edema are discussed as the basic events in the pathogenesis of MCE .