Jean-Marie Brucher

Acute corticosteroid myopathy in intensive care patients.

Several recent studies have attributed the occurrence of acute myopathy in intensive care unit patients to the combination of corticosteroids and neuromuscular junction blocking agents (NMBAs) used for mechanical ventilation. We present 4 patients who developed acute myopathy after administration of high doses of glucocorticoids during sedation with propofol without any NMBAs. All patients had elevated creatine kinase levels. Electrophysiological studies indicated normal motor and sensory nerve conduction velocities but reduced motor nerve response amplitudes. Needle electromyography identified abnormal spontaneous activity; motor unit potentials were polyphasic of low amplitude and short duration, characteristic of a myopathic process. Muscle biopsy demonstrated a prominent acute necrotizing myopathy in all 4 patients with a loss of thick filaments. Our observations support glucocorticoids rather than NMBAs as the main offending drug in acute corticosteroid myopathy. The predisposing factor should be the hypersensitivity of paralyzed muscles to corticosteroids regardless of the drug inducing paralysis: NMBAs or propofol.

On an autosomal dominant form of retinal-cerebellar degeneration: an autopsy study of five patients in one family.

We describe a family with an autosomal dominant form of retinal-cerebellar atrophy. There is an extreme variability in age of onset and severity of the clinical symptoms: some patients remain nearly asymptomatic throughout their entire life; others develop severe retinal and cerebellar symptoms after the age of 35 years; others suffer from a severe disorder with onset in adolescence and death during the third decade of life; in others the onset is in early childhood with prevalence of cerebellar symptoms. There is neither dementia nor epilepsy in any of the patients. Four out of five autopsies showed a severe retinal atrophy, and all five autopsies were also characterized by (1) a cerebellar atrophy affecting the spinocerebellar and olivocerebellar tracts, the cerebellar cortex and the efferent cerebellar pathways, (2) an involvement of the pyramidal pathways and of the motor neurons of brain stem and spinal cord, and (3) an atrophy of the subthalamic nucleus and to a much lesser extent of the pallidum, with also some damage to the substantia nigra. The posterior columns are much less affected except in one patient. In this family, we have excluded linkage with the two loci for spinocerebellar ataxia, i.e., SCA1 on chromosome 6p and SCA2 on chromosome 12q as well as with the locus for Machado-Joseph disease (MJD) on chromosome 14q. A genome-wide search is currently being performed to detect the disease locus responsible.

Focal ependymal differentiation in choroid plexus papillomas

SummaryChoroid plexus papillomas are usually easily distinguishable from papillary ependymomas by their delicate fibrovascular stroma and their cytologic similarity to normal choroid plexus epithelium. Exceptionally, however, examples are met which give rise to diagnostic difficulty. We therefore tested 22 choroid plexus papillomas for the presence of glial fibrillary acidic (GFA) protein using the immunoperoxidase technique. Positivity for the protein was found focally in epithelial tumor cells in nine of the 22 papillomas. All were in adults ranging from 19–66 years of age. Eight of the nine tumors originated in the 4th ventricle or from one of its lateral recesses. In six papillomas showing GFA protein in the cells, intracellular fibrils were found in a small number of elongated epithelial cells with the PTAH and/or Masson trichrome stains; in all these six cases, the GFA protein-positive cells were considerably more numerous than cells containing fibrils. Normal choroid plexus epithelium lacks GFA protein, but pathologically altered ependymal cells are often GFA protein-positive. Our findings therefore suggest that focal divergent glial (presumably ependymal) differentiation may be expressed in neoplastic choroid plexus epithelium, consistent with the origin of this epithelium from primitive neuroepithelial (ventricular) cells.

Pyruvate-dehydrogenase Deficiency - Clinical and Biochemical-diagnosis

A female neonate with pyruvate dehydrogenase (PDH) deficiency is presented with clinical, radiologic, biochemical, neuropathologic, and molecular genetic data. She was dysmorphic, with a high forehead, lowset ears, thin upper lip, upturned nose, and rhizomelic limbs. Cranial MRI revealed severe cortical atrophy, ventricular dilatation, and corpus callosum agenesis. Pyruvate and lactate levels were increased in CSF and blood. Urinary organic acid profile was compatible with PDH deficiency. PDH activity was normal in fibroblasts, lymphocytes, and muscle. The PDH E1-alpha gene was sequenced and a single base mutation was found within the regulatory phosphorylation site in exon 10. It is postulated that this mutation causes a cerebral form of PDH deficiency. Tissue-specific expression of the disease could be explained by differential X chromosome inactivation because the PDH E1-alpha gene is located on this chromosome. Dysmorphism with severe cerebral malformations in female patients merits a metabolic evaluation, including determination of lactate and pyruvate levels in CSF.

Lacunar infarctions due to cholesterol emboli.

Background and Purpose: Hypertension is commonly considered the major cause of lacunar infarctions. However, in some cases, it has been suggested that lacunes could be caused by cerebral emboli from cardiac or carotid sources. Cholesterol cerebral emboli have been rarely reported as a cause of lacunes. Case Description: We describe a 79-year-old patient with a progressive multi-infarct dementia who developed transient motor aphasia and paresis of the right arm. Computed tomography showed lacunar infarcts in the right caudate nucleus, left thalamus, and left putamen, as well as an old right frontal infarction. Neuropathological examination demonstrated no prominent vascular hyalinosis, but did show multiple cholesterol emboli occluding small arteries around lacunar infarcts and leptomeningeal arteries near cortical infarcts. The cholesterol material presumably originated in the extended atheromatous changes along the aortic arch. Conclusions: Our report confirms that lacunes can be caused by cholesterol emboli in some patients. Small cerebral emboli should not be overlooked as a cause of lacunes.

Neuropathological Findings of a Patient With Pyruvate Dehydrogenase-e1-alpha Deficiency Presenting As a Cerebral Lactic-acidosis

SummaryNeuropathological findings are reported of a 6-month-old female child with a “cerebral” lactic acidosis. A mutation in the pyruvate dehydrogenase (PDH) E1α gene was found. Gross examination of the brain revealed a severe thinning of the cerebral parenchym, a marked hydrocephalus sparing the aqueduct and fourth ventricle, agenesis of the corpus callosum and heterotopic noduli of gray matter in subependymal regions. Microscopical examination showed heterotopic inferior olives, absent pyramids and focal neuroglial overgrowth into meninges. In addition some heterotopia of Purkinje cells and dysplasia of the dentate nuclei were observed. There was a marked vascular proliferation with many thin-walled, congestive vessels in the cerebral and cerebellar white matter, and to a lesser extent in the striatum. To our knowledge these cerebellar and vascular abnormalities have not been reported before in patients with “cerebral” lactic acidosis. The combination of these neuropathological findings might be characteristic for PDH deficiency and more specifically for its E1α subtype. Neuropathological examination could lead to the retrospective diagnosis of PDH E1α deficiency in those cases where biochemical investigations were not or incompletely performed. This may have potential implications for genetic counseling.

Ultrastructural study of medullomyoblastoma

SummaryA case of cerebellar medullomyoblastoma in a young boy was investigated by electron microscopy. The neuroectodermal component shows the characteristics of a desmoplastic medulloblastoma. The mesodermal component consists of more or less differentiated cross-striated muscle cells. Undifferentiated muscle cells are very similar to proliferated endothelial cells of blood vessels within the muscular component, so that an origin of this component from pluripotential endothelial cells of the vessel wall is suggested. This tumor is considered a malignant teratoid because of the derivation from two blastodermic layers and because of the midline localization in children suggesting a malformative origin.

Activity of alkaline and acid nucleases in tumors of the human central nervous system: Histochemical study

The alkaline and acid DNAse and RNAse were histochemically investigated in the tumors of the human central nervous system. In most of the malignant tumors, none of the four types of nucleases manifested any activity, whereas in the benign tumors this activity was similar to that of those normal tissues from which they originated. The necrotic areas of malignant tumors had a peripheral zone in which the activity of the nucleases reappeared. This reappearance was probably due to the splitting of the nuclease‐inhibitor complex. The significance of nucleases in malignancy and their possible role in the protection of the genetic stability of the cell are briefly discussed.

Potential clinical gain of proton (and heavy ion) beams for brain tumors in children

At the Tumor Center of the Catholic University of Louvain, patients are currently treated, since 1978, at the cyclotron with fast neutrons produced by 65 MeV protons on a beryllium target (63). The cyclotron, located at Louvainla-Neuve, is able to accelerate protons at energies up to 90 MeV (62). In these conditions, proton beam therapy could be performed for rather superficial tumors, such as uveal melanomas. Other types of tumor and/or sites are contemplated; the 90 MeV proton beam penetration is about 6 cm in tissues. In collaboration with the Neuropediatry and the Neuropathology Departments of the University Clinics St-Luc, the potential benefit of proton beams for the treatment of brain tumors in children has been analysed. The central nervous system (CNS) tumors in children (up to 15 years) differ from those in adults as far as incidence, histology, location and actual prognosis are concerned. The therapeutic approach should then also be different; the late sequellae have to be kept in mind especially for children.

Subacute sensory neuronopathy associated with Sjögren's sicca syndrome.

SummarySensory subacute neuropathies associated with sicca syndrome without any systemic involvement have been reported rarely. A sixth case is described with what appears to be the first report of muscle and nerve biopsy findings. The histological studies revealed axonal degeneration without vasculitis in the sural nerve, and a slight denervation process and a discrete myositis in the gastrocnemius muscle, reflecting a subtle systemic disorder. The clinical course of a long-standing subacute sensory neuropathy, the biopsy-documented axonal degeneration, and the neurophysiological findings suggest involvement of the dorsal root ganglia.