Cerebral infarction in the human fetus near term

Fetal stroke and cerebrovascular disease: Advances in understanding from lenticulostriate and venous imaging, alloimmune thrombocytopaenia and monochorionic twins

Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.

Prenatal stroke in a neonate heterozygous for factor V Leiden mutation

The authors report an infant with congenital hemiplegia associated to heterozygosity for factor V Leiden. Prenatal stroke in the left cerebral hemisphere was diagnosed by ultrasonography at the 28th week of pregnancy, and followed up until birth. Although neonatal neurologic examination was normal, a moderate right hemiparesis developed along the 1st months of life. Coagulation studies performed in the neonatal period and at the age of 18 months revealed activated protein C resistance due to factor V Leiden mutation (R506Q). There are some previous reports of stroke associated to this mutation in near or at term neonates, but to our knowledge this is the stroke detected at the most early stage of fetal development.

Factor V Leiden and genetic defects of thrombophilia in childhood porencephaly

AIMS

To determine to what extent the Arg506 to Gln point mutation in the factor V gene and further genetic factors of thrombophilia affect the risk of porencephaly in neonates and infants.

METHODS

The Arg506 to Gln mutation, factor V, protein C, protein S, antithrombin, antiphospholipid antibodies and lipoprotein (a) (Lp(a)) were retrospectively measured in neonates and children with porencephaly (n = 24).

RESULTS

Genetic risk factors for thrombophilia were diagnosed in 16 of these 24 patients: heterozygous factor V Leiden (n = 3); protein C deficiency type I (n = 6); increased Lp (a) (n = 3); and protein S type I deficiency (n = 1). Three of the 16 infants had two genetic risk factors of thrombophilia: factor V Leiden mutation combined with increased familial Lp (a) was found in two, and factor V Leiden mutation with protein S deficiency type I in one.

CONCLUSIONS

The findings indicate that deficiencies in the protein C anticoagulant pathway have an important role in the aetiology of congenital porencephaly.

Antenatal cerebral necrosis in monochorionic twins

Antenatal cerebral white matter necrosis occurs relatively frequently in monochorionic twins, particularly when one twin has died in utero or in the twin-twin transfusion syndrome. A case of antenatal cerebral necrosis in both of liveborn monochorionic twins is presented. It is proposed that placental artery-to-artery or vein-to-vein anastomoses may predispose twin fetuses to hemodynamic instability. Fluctuations in blood pressure or blood volume may then result in cerebral necrosis, without requiring the death of one twin or transfer of a blood-borne factor from one twin to the other.

Microgyric and necrotic cortical lesions in twin fetuses: original cerebral damage consecutive to twinning?

Extensive cortical necrosis associated with malformative microgyric-like lesions and with necrotic lesions of the white matter was observed in two male 25 week fetuses. These cases differed from previously reported cases of brain damage in monozygotic twins: both fetuses were affected and the lesions occurred early in pregnancy, before the end of neuronal migration, thus resulting in a cortical malformation associated with destructive lesions.

Behavior disorders in mentally retarded persons, the dually diagnosed: factors of pathogenesis

The present report considers organic factors of pathogenesis, in addition to environmental factors, as causal processes in cases of dual disability of mental retardation and behavior disorders. Relevant to organic pathogenesis, in cases of dual diagnosis, basic biological processes are presented, mechanisms concerned with gestational and birth complications that led to fetal-neonatal hypoxic cerebral cortical damage. In such cases, dual diagnosis manifestations of mental retardation and behavior disorders, together with other chronic cerebral disabilities, may be attributed to residues of fetal-neonatal cerebral damage.

Obstetric malpractice litigation: the pathologist's view

In obstetric malpractice litigation, there are two main bases of defense: the clinical basis and the pathogenesis basis. The malpractice suit in most cases involves an infant delivered at term that later develops cerebral palsy. Despite the fact that much information has been elucidated about the pathogenesis of cerebral palsy, the defense is often jeopardized by an inadequate presentation of relevant causal mechanisms, pathogenesis. Studies in recent years with correlated clinical and pathologic investigations have provided evidence that the occurrence of cerebral palsy is a time marker, reflecting cerebral damage incurred during the premature period, and does not result from the events of labor and delivery at term. There is broad need generally and in legal situations for clinicians and pathologists to become knowledgeable in comprehensively correlating obstetric factors with fetal-neonatal systemic pathologic conditions and with neuropathologic effects.

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 .

Infantile multicystic encephalomalacia after maternal bee sting anaphylaxis during pregnancy

We report a case of infantile multicystic encephalomalacia after maternal bee sting anaphylaxis in the 30th week of pregnancy. The clinical features and findings at necropsy are described, and it is suggested that these are the result of severe fetal hypoxia secondary to maternal hypotension.

Multicystic encephalomalacia in liveborn twin with a stillborn macerated co-twin

Computed tomography showed multiple cystic lesions in the brains of three infants with cerebral palsy. Each patient was the product of a twin pregnancy with a stillborn, macerated co-twin. In two patients angiography was performed and suggested that the cystic lesions were multicystic encephalomalacia due to perinatal arterial occlusion.

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.

Multiple cystic and focal encephalomalacia in infancy and childhood with brain stem damage

Two cases are described in which damage to the brain stem was associated with extensive necrosis of the cerebral hemisphere. In the first case--a monochorionic twin--there was clear evidence that injury of an ischaemic or hypoxic type had occurred during fetal life and some evidence that an inadequate share of the placental circulation was an important aetiological factor. In the second case death occurred 4 yr after an asphyxial episode at birth. The lesions in the hemispheres and brain stem were extensive, although less than in the first example. The lesions are discussed in the context of our knowledge of the anatomy and physiology of the developing nervous system. Although they cannot as yet be fitted into the concepts of "critical periods" and "vulnerable periods" of development, this is perhaps because observations on human cases are scanty in comparison with the extensive animal studies which have been reported. The lesions are contrasted and compared with those seen in animals.