Diagnostic aspects of cerebrocortical necrosis

Specimens from cattle and sheep suspected of having cerebrocortical necrosis (CCN) were studied. Rumenal contents were examined for thiaminase-producing bacteria. Thiaminase activity was assessed in rumenal contents. The thiamine concentration of liver, brain and heart was determined and erythrocyte transketolase assessed. Diagnosis in each case, whether positive or negative for CCN, was decided by histopathological examination. There was a substantial agreement between the biochemical findings and the histological diagnosis indicating that a provisional diagnosis may be made on clinical and biochemical data alone. The findings are discussed in relation to other diseases which have the same neuropathological features. Attempts to isolate thiaminase-producing bacteria, which may be implicated in the aetiology of CCN, were inconclusive.

Periventricular leukomalacia complex

At autopsy in the past three years, a new complex of CNS lesions has appeared in 54% (50/93) of the brains of premature infant cadavers that have come from our neonatal intensive care unit. This complex consists of necrotizing lesions in the periventricular white matter and in the gray nuclei of the cerebral hemispheres, the hippocampus and subiculum, cerebellar folia and white matter, and basis pontis. This entity is called the periventricular leukomalacia complex, since the distribution of lesions is similar, yet much more severe, than that described by Banker and Larroche in 1962. Clinical studies have indicated that these lesions may be related to long periods of time at high blood oxygen or prolonged periods in which PO2 and pH fluctuated widely.

Old subependymal necrosis and hemorrhage in the prematurely born infants

Old subependymal hemorrhage (SEH) and old subependymal necrosis (SEN) were found in 18 (23%) and 14 (19%) cases respectively out of a total of 78 prematurely born infants who survived more than 3 weeks. Most of the lesions were recognized in the region of th stria terminalis. A nonhemorrhagic infarct (SEN) might occur at the stria terminalis in the perinatal period of the premature infant, following focal ischemia or hypoxia, and on occasion predispose to the production of subependymal hemorrhage in impaired cerebral vascular autoregulation.

Multicystic encephalomalacia of infancy: clinico-pathological report of 7 cases

Clinical follow up and complete neuropathological examination was made on seven cases of multicystic encephalomalacia of infancy. Etiological factors were carefully studied in all the cases. They consisted of prenatal injuries presenting as a cord prolapse, in 3 cases; prolonged labour with marked cyanosis; abdominal trauma during gestation, and various maternal infections at different stages of pregnancy. Pathological interest is centred on the variable involvement of different areas of the brain, generally sparing the cerebellum and brain stem, and being minimal or absent in the occipito-temporal areas. This distribution may be explained by a different effect of the "causal agency" on these different areas, or by a different capacity of these regions to react against injury. Among the etiological factors reviewed in the literature, the anoxic theory appears the most probable, as there was a close parallelism between lesions and vascular areas, mainly the carotid and vertebro-basilar systems.

Neuronal ischemic injury: light microscopy, ultrastructure and biochemistry

A uniform, predictable pattern of cellular abnormalities is seen after complete, irreversible ischemic injury to the central nervous system. This is in contrast to the heterogeneous, multifocal picture which characterizes incomplete ischemia. The range of abnormalities in neuronal soma after an arterial occlusion changes considerably as a function of time and site. There is no single pattern of neuronal alteration that can be ascribed exclusively to ischemia. Red neurons are a relatively late (about 18 h) indicator of ischemia and are seen only in areas where blood supply is marginal. In addition to depletion of high-energy-phosphate reserves, brain ischemia results in characteristic alterations of amino acid concentrations in the ischemic tissue. Glutamate, glutamine, and aspartate either decrease or remain constant while alanine increases. Proportional decreases in the former three amino acids may be explained by simple dilution due to edema. Increases in alanine relative to glutamate and aspartate may be utilized as a biochemical index of perfusion to various brain regions.

Cerebral white matter lesions in sudden infant death syndrome

In 21.6% of infants who died of sudden infant death syndrome, the cerebral white matter showed areas of leukomalacia. Of those infants with congenital heart disease, 24.8% had lesions, whereas 4.4% of infants who died from known acute causes had lesions. The sites of the cerebral white matter lesions, subcortical or periventricular, seem to be related to the age of the infant.

Avian encephalomalacia in Barbados, West Indies: a description of spontaneous field cases with feed analyses

The clinical, necropsy and histopathological findings in four natural outbreaks of encephalomalacia are reported. Feed analyses implicated low levels of vitamin E as the probable cause of the condition. Treatment with vitamin E has proved to be very effective. The instability of vitamin E in animal feed ingredients during long periods of shipment into the Caribbean may be important in the pathogenesis of the disease.

[Subacute necrotizing encephalomielopathy. Leigh syndrome (author's transl)]

A 6-month-old girl with familiar history of two dead sisters few months old, was admitted to the Hospital with a neurological process. After her admission progressively worsened until her death. The patient had clinical manifestation of proximal tubular acidosis. Levels of lactic and piruvic acid were normal. Necropsic study was compatible with the diagnoses of subacute necrotizing encephalomielopathy of Leigh syndrome.

[Pseudo-tumoral softening of the cerebellum]

The author establish an onerall picture of cerebellar infarction with brain stem compression after reviewing 63 cases published in the literature and 4 personal observations. The frequency of this affection can be compared with that of cerebellar hematomas. Diagnosis is based on its predominance in males, the early age at which it appears, its rapid and typical onset, and the delayed signs of brain stem compression. Conventional neuroradiological procedures show an expanded cerebellar volume, and the scanner can specify the ischaemic nature of the lesion. As soon as changes in consciousness occur surgical decompression is necessary, first by external drainage of C.S.F. and later, if necessary, by direct access to the postdrior fossa.

Polioencephalomalacia of dogs with thiamine deficiency

A naturally occurring neurological disease occurred in six dogs fed cooked meat. Clinical signs were anorexia, progressive spastic paraparesis, recumbency, convulsions and death. The disease was characterized by bilaterally symmetrical spongy change and necrosis of brainstem nuclei with a lesion distribution pattern similar to that in thiamine deficient foxes and cats. An associated thiamine deficiency was evidenced by decreased thiamine levels in the blood of one dog and in the food of another, and rapid remission of clinical signs in a dog given thiamine hydrochloride. Thermal destruction of thiamine through cooking of the foods probably caused the dietary deficiency.

[Obliterating parietal hemodissection or vertebro-basilar dissecting aneurysm]

The authors report the pathological and clinical findings of a dissecting aneursym of the basilar artery in a 32 year old man up till then in good health, who died two months later. The pathological study showed bilateral lesions of osteo-malacia in the neighborhood of the pons due to hemo-dissection affecting the right vertebral artery just before it enters the dura-mater, then its intra-cranial portion, the basilar trunk and the first part of the right posterior cerebral artery. The originality of this case resides in the finding of segmental stenosing panarteritis of the same right vertebral artery in the segment which precedes dissection. On this occasion, the authors carried out a review of the literature and considered a few comments on the etiology, the pathology, clinical findings and classification of this unusual disease.

Thiamine triphosphate levels and histopathology. Correlation in Leigh disease

Thiamine and thiamine triphosphate (TTP) values were assayed in various brain regions in 11 controls and 13 patients with subacute necrotizing encephalomyelopathy (SNE, Leigh disease). The TTP values of normal brain were 5% of the total thiamine value. The relative TTP (or % TTP) level was consistently low in the pons, midbrain, and cerebellum of all the SNE brains. Twenty-five percent of the SNE brains had normal TTP levels in the frontal region. The TTP values correlated with the degrees of pathologic involvement in all sampled regions of the brain except the cerebellum. The concentration of thiamine in the mammillary bodies exceeded its concentration elsewhere in both control and SNE brains. The finding of low TTP levels in morphologically abnormal regions supports the hypothesis that TTP deficiency is etiologically related to SNE.

Leukoencephalomalacia: a mycotoxicosis of Equidae caused by Fusarium moniliforme Sheldon

When 2 horses were dosed with cultures of a Fusarium moniliforme isolate that had previously caused only hepatosis, 1 developed brain oedema and hepatosis, and the other only leukoencephalomalacia. A 3rd horse developed both leukoencephalomalacia and hepatosis after being dosed with another isolate obtained from maize which was associated with a natural outbreak of the nervous form of the disease. Since leukoencephalomalacia and hepatosis could be induced by the same culture material, it was concluded that both syndromes were manifestations of the same toxicosis. There was also some evidence that leukoencephalomalacia might be specifically induced by the administration of smaller doses of the culture material to horses over a longer period. The clinical signs of nervous disorder included ataxia, paresis, apathy, hypersensitivity, frenzy, and other locomotory and psychic disturbances. Autopsy showed that the brains were oedematous, and focal areas of liquefactive necrosis were present in the cerebral white matter. In 1 case the malacic areas were not confined to the subcortical white matter but were microscopically visible in the cerebral cortex as well. An histopathological examination of the areas bordering on the malacic areas revealed rarefication of the white matter, perivascular haemorrhages, oedema and cellular infiltration composed mainly of plasma cells and eosinophiles. Many of the macrophages in these areas contained lipfuscin-like granules, but these granules also occurred extracellularly in the neuropil. In the layers of the cortex nearest the malacic areas, satellitosis and neurophagia were commonly seen.

Diabetes insipidus in hypoxemic encephalopathy

Diabetes insipidus developed in two patients who experienced severe hypoxemia as a consequence of drug-induced respiratory failure. Post-mortem examination revealed generalized cerebral edema, encephalomalacia, and a profound and diffuse loss of neurons. Hypoxemia-induced diabetes insipidus may indicate that the patient is suffering from severe brain damage.

The cortical form of subacute necrotizing encephalopathy of the Leigh type. A light- and electron-microscopic study

The present paper is a clinico-pathological study of a 14-year-old boy with a chronic, progressive occipital syndrome for which he was operated upon. Postoperatively, metabolic acidosis developed. Pathological anatomy revealed spongy necrosis of the thalamus and corpora quadrigemina with the typical histological features of Leigh's necrotizing encephalopathy. Similar necrotic lesions had developed in the occipital cortex. At this level apart from the typical foci, cavitating necrosis was found as well as involvement of the smaller vessels of the pial circulation. Electron microscopy revealed vascular and glial changes suggestive of primary mesenchymoglial dystrophy. The histiocytes presented intracytoplasmic multiplication of lysosomes and their transformation into lipofuscin pigment. The changes demonstrate a juvenile cortical form of Leigh's subacute necrotizing encephalopathy.