Sudden infant death with periventricular leukomalacia

Periventricular leukomalacia (PVL) is a form of cerebral infarction occurring in neonates, particularly in low-weight and premature infants. PVL is well-known to neonatologists, but generally considered nonfatal. Many infants with PVL die in the hospital with multiple medical problems. Those infants with PVL who survive because of intensive care will have serious motor and sensory deficits, but these problems are rarely recognized before one year of age. When infants with PVL die at home, death seems sudden and unexpected. However, it is important to distinguish death caused by PVL from the Sudden Infant Death Syndrome because the implications for the family are quite different. This case report emphasizes that PVL may be fatal.

Encephalomalacia associated with hypovitaminosis E in turkey poults

Four-to-five-week-old turkey poults fed a diet markedly deficient in vitamin E (alpha-tocopherol) abruptly developed neurologic signs such as tremor, incoordination, and recumbency shortly after being moved to new quarters. Serum concentrations of alpha-tocopherol in birds on this diet were significantly lower than control values. Associated lesions included recent ischemic necrosis of the cerebellum and spinal cord. The condition closely resembled nutritional encephalomalacia of chicks. This report represents the initial published description of that entity in turkeys.

An outbreak of cerebrocortical necrosis (polioencephalomalacia) in goats

In a herd of 30 Boer goats, 3 young goats developed nervous signs including apparent blindness. In 2 of the goats a diagnosis of cerebrocortical necrosis was confirmed by the demonstration of lesions typical of the disease on histopathological examination. Lead concentrations in the renal cortex were well below the level regarded as indicative of lead poisoning in ruminants. The reason for the outbreak was not clear, but the feeding of concentrate and poor quality roughage may have been contributory factors. Cerebrocortical necrosis appears to be unusual in goats, compared to cattle and sheep, but it should be entertained in the differential diagnosis of caprine nervous diseases.

Ataxia/paresis syndrome of sheep in West Africa associated with bilateral multifocal cerebrospinal poliomalacia

Between 1976 and 1981 a specific neurological disorder of sheep was observed in Ghana. It was encountered on eight properties on some of which it was responsible for losses of up to 72 per cent of the sheep stock in some years. The condition affected mainly adult ewes, and was characterised clinically by a brief period of ataxia, followed by paresis prostration and death in four to five days. Morphological examination of nine affected animals revealed significant lesions only in the central nervous system. These consisted of oedema of the intracellular glial compartment and bilateral, sometimes symmetrical, foci of spongy transformation, malacia and haemorrhage in the grey matter of the brain stem, cerebellum and spinal cord. The aetiology of ataxia/paresis syndrome was not determined but some possibilities are discussed in the context of other naturally occurring and experimental focal malacic disorders in animals.

Early echographic findings in non-hemorrhagic periventricular leukomalacia of the premature infant

The ultrasonic detection of periventricular leukomalacia is described in two neonatal patients. Confirmation of this condition by CT and post mortem was obtained in one case. CT scan and further echography was positive in the other. Neither patient had evidence of an intracranial hemorrhage. It is suggested that echography is of value in the early diagnosis of this lesion which may be similar to intraparenchymal hemorrhage in its mechanism and prognosis.

Sonography of neonatal periventricular leukomalacia: recent experience with a 7.5-MHz scanner

This study compared the relative efficacy of 5.0- and 7.5-MHz (high-resolution) transducers in the sonographic evaluation of cystic periventricular leukomalacia (PVL). Of 668 premature neonates evaluated by cranial sonography over a 4-year period, 34 were diagnosed as having PVL. Of these 34 neonates, 17 were examined with both 5.0- and 7.5-MHz transducers. Fifty-two neonates with no evidence of PVL also were evaluated by sonography with the two different-frequency transducers to determine the normal appearance of the neonatal brain. Among the neonates with PVL, features of the disease that have not been observed with routine 5.0-MHz transducers were apparent with use of the 7.5-MHz transducer: 7.5-MHz scanning clearly identified small areas of cystic PVL in three (17.6%) of 17 neonates that were not visible using the lower-resolution technique. The higher-resolution scanning also identified widening of the interhemispheric fissure by anechoic cerebrospinal fluid and demonstrated the falx as a distinct structure. The latter two superficial abnormalities were identified in combination with enlargement of the lateral and third ventricles, suggesting that diffuse cerebral atrophy accompanies PVL in most cases. The excellent near-field resolution of 7.5-MHz technology makes it the preferred method for the evaluation of PVL in the preterm neonate.

[Morphological characteristics of a substantia alba lesion of the cerebral hemispheres in newborn infants with periventricular leukomalacia and sepsis]

Neurohistological and electron microscopy studies of the foci of periventricular leukomalacia allowed defining 3 stages in their development: necrosis, resorption and formation of the glial cicatrix or a cyst. Comparative study of the lesions in two groups of neonates (with and without sepsis) showed that sepsis promoted the process persistence and development of new pathological foci. One of the possible pathogenetic mechanisms might be the thrombosis of brain white substance vessels.

Multicystic encephalomalacia: CT appearance and pathological correlation

Perinatal insults, including anoxia, may lead to a form of cerebral necrosis designated multicystic encephalomalacia. This common condition is characterized by (a) moderate atrophic ventricular dilatation, (b) intact ventricular walls with thickened subependymal glial layer, (c) multiple cysts of irregular size and shape distributed throughout the cerebral white matter and the inner layers of the cortex bilaterally, and (d) relative sparing of the orbital surfaces of the frontal lobes, the temporal lobes below the superior temporal gyri, the basal ganglia, the cerebellar hemispheres, and the spinal cord (except for secondary degeneration of corticospinal tracts).

Acquired perinatal leukoencephalopathy

Between 36 and 44 weeks after conception, telencephalic white matter in the newborn appears to be particularly vulnerable to insults that result in morphological disturbances. Available evidence indicates that this disorder (or group of disorders), named acquired perinatal leukoencephalopathy, reflects a decrease in blood flow through the distal vessels supplying paraventricular white matter and/or a metabolic disturbance produced by, or in response to, an infectious agent. Major advances in our understanding of the causes, mechanisms, and sequelae of acquired perinatal leukoencephalopathy may be made in the next decade because of improvement in brain imaging techniques, improved survival of high-risk babies, and relatively routine follow-up of these high-risk babies.

Histopathological changes in the brain of mice given Clostridium perfringens type D epsilon toxin

The distribution, severity and frequency of brain lesions produced in mice by the administration of Clostridium perfringens Type D epsilon toxin were examined by light microscopy. The granular layer of the cerebellum was the area most frequently affected in mice given single doses of toxin. Sequential changes in brain morphology were examined from 1 h to 7 days after injection of toxin. Lesions progressed from an initial vasogenic oedema to malacic foci which commonly were focal and bilaterally symmetrical, with a predilection for white matter. The topographical distribution of these malacic areas is discussed.

Ultrastructural changes in the brain of mice given Clostridium perfringens type D epsilon toxin

Mice were given lethal and sublethal doses of Clostridium perfringens Type D epsilon toxin and the early morphological changes in perfusion-fixed intoxicated brains were examined from 30 min to 6 h post-inoculation. The initial ultrastructural finding was swelling of astrocytes, especially the perivascular extensions of these cells. Astrocytes in the cerebellum appeared to be particularly sensitive to this toxin. These changes were quickly followed by evidence of severe endothelial damage, with the endothelial cytoplasm becoming attenuated, vacuolated and very electron-dense. A pathogenetic sequence of events leading to malacia, derived from ultrastructural observations, is proposed.

Caprine encephalomyelomalacia

Six cases of encephalomyelomalacia in dairy goats 3 1/2 to four months of age are described. Neurologic signs had an abrupt onset and passed rapidly from ataxia to paralysis. All goats were killed after six to ten days and had spinal cord and brain stem lesions--always more extensive and severe in the cord. The bilaterally symmetrical necrotic lesions were restricted to the ventral and intermediate gray substance in the cord and to certain brain stem nuclei. The spinal cord enlargements were affected especially.

[Clinico-anatomic correlations of aphasia syndromes in the acute state of brain insult]

The data from an analysis of 104 patients who died in the acute stage of apoplexy are reported. A clinical anatomic and neuropsychological analysis as well as comparison with the foci of the lesions was made. The data confirmed once more the results of many authors--from Broco to recent days and showed that these areas formed the "nucleus" of the cerebral mechanism of the speech. Inspite of the fact that the speech as a function could not be localized in one area of the Central Nervous System, the so called "speech areas" of the dominant hemisphere play an important role in the functioning of the speech system--its "cerebral mechanisms" are set there.

Developmental changes of glial fibrillary acidic protein and myelin basic protein in perinatal leukomalacia: relationship to a predisposing factor

Focal white matter necrosis is frequently seen in the brains of infants with perinatal cerebral hypoperfusion. Periventricular leukomalacia (PL) occurs in the deep white matter of premature and term neonates and subcortical leukomalacia (SL) in the subcortical white matter of young infants. Using immunoperoxidase methods in normal infants, glia positive for glial fibrillary acidic protein (GFAP) were found first in the deep zones of white matter and with increasing age they became more prominent in the subcortical zone. They increased diffusely in the deep or subcortical zones of the cases of PL or SL, respectively. The number of myelin basic protein-positive glia is much larger than that of GFAP-positive glia in the cases of old PL. These findings suggest that an increased number of positive glia may be a reaction to hypoxic, ischemic, or toxic insults, or this shifting, transient increase of positive glia in cerebral white matter may be one of several predisposing factors leading to perinatal leukomalacia. Furthermore, positive staining of GFAP and MBP for reactive astrocytes in old PL suggests that at a certain stage of gliogenesis both GFAP and myelin basic protein may be present within the same cell.

[Pathological anatomy of hemorrhages into the cerebellum of fetuses and newborn infants]

Fifty-eight (6,2%) cases of hemorrhages into the cerebellum (HC) that were found among 899 perinatal and neonatal necropsies were studied; hemorrhages less than 0,5 cm in diameter were not included into the material examined. HC were prodominantly observed in premature newborns. The main cause of death of newborns and intranatally dying fetuses with HC was a skull trauma occurring during delivery. HC were subdivided into 3 groups: 1) those provoked by pressure on the upper surface of cerebellum hemispheres followed by vessel compression; 2) those provoked by blood stasis in cerebellum venae as a result of a venous circulation damage in the brain and sinuses; 3) HC resulting from the blood transport from the fourth ventricle of the brain during intraventricular hemorrhages. The morphology of each HC type is described. The importance of HC recording for the determination of a direct cause of death is stressed.

Developmental neuropathology in bronchopulmonary dysplasia: alteration of glial fibrillary acidic protein and myelination

Developmental changes of glial fibrillary acidic protein (GFAP) and myelination were examined in the brains of 25 children with bronchopulmonary dysplasia (BPD). Widespread GFAP-positive, bouquet-shaped glia occurred in the cerebral white matter and medulla oblongata of most cases and increased during the perinatal period, independent of the presence of luekomalacia. Acceleration of myelination was suggested in five of 10 cases during the period of 40 to 48 weeks postconceptional age, just before myelin sheaths normally appear. However, in two of four cases seen during late infancy myelination was delayed. The increase of GFAP-positive glia may be related to the induction of myelination. On the other hand, increased astroglial processes may occur secondary to chronic hypoxia and may interfere with myelination, accounting for the poor myelination seen in late infancy.

Polioencephalomalacia-like disease in pronghorns (Antilocapra americana)

A disease resembling thiamine-responsive polioencephalomalacia of domestic ruminants is described in four wild pronghorn from Saskatchewan. One animal was found dead, two were recumbent and unable to rise and the fourth was staggering and ataxic. Lesions were confined to the brain and consisted of brain swelling with herniation, symmetrical hemorrhagic foci in the thalamus and brainstem, and laminar necrosis of cortical neurons. All animals had been eating grain prior to their death. Possible pathogenetic mechanisms including changes in rumen microflora resulting in thiamine deficiency, plant and salt intoxication are discussed.

Brain maturation and types of perinatal hypoxic-ischemic encephalopathy

The degree of brain maturation and the location of hemorrhage in the germinal layer and of periventricular leukomalacia were analyzed in 85 newborn brains. The average age of the premature brains with hemorrhage was 31 weeks and of those with leukomalacia 37 weeks. Hemorrhage was more frequently found in the frontal regions, while periventricular leukomalacia predominated in the parieto-occipital regions. This study confirms that the type and the location of the hypoxic-ischemic perinatal cerebral damage are dependent on the rate of regression of the embryonic type of periventricular arterial vascularization in the premature brain.

X-linked Leigh's syndrome

Two male half siblings developed rapid progression of neurologic symptoms at 11/2 and 21/2 years of age. Neither boy had a metabolic acidosis. Characteristic features of subacute necrotizing encephalomyelopathy, the neuropathologic basis of Leigh's syndrome, were demonstrated at autopsy. X-linkage of the disorder was considered because the boys had different fathers. An X-linked form of Leigh's syndrome was supported by a review of the literature, which showed an unexplained male/female ratio in Leigh's syndrome of 1.83/1, and a significant excess of male-male siblings. An X-linked form of Leigh's syndrome would explain the excess of males, and may account for some of the clinical and biochemical heterogeneity.