Hypotensive brain stem necrosis or cardiac arrest encephalopathy?

Summary Selective symmetrical necroses of many tegmental brain stem nuclei including motor cranial nerve nuclei, superior and inferior colliculi, cuneate and gracilis nuclei, and others are known as hypotensive brain stem necrosis (Gilles 1969). We found such lesions in eight infants and seven adults. Examination of their clinical records revealed a well documented episode of cardiac arrest in each case. Cardiac output was restored in all but one patient 5 min to 4 h after the beginning of resuscitation. All patients remained comatose in a decerebrate state up to their death 17 h to 4 weeks after adminssion. Our findings and a review of the literature indicate that this type of lesion relates specifically to cardiac arrest. The term hypotensive brain stem necrosis is a misnomer and should be replaced by the term cardiac arrest encephalopathy.     

Cardiac arrest-induced regional blood–brain barrier breakdown,edema formation and brain pathology: a light and electron microscopic study on a new model for neurodegeneration and neuroprotection in porcine brain

Brief cardiac arrest and survival is often associated with marked neurological alterations related to cognitive and sensory motor functions. However, detail studies using selective vulnerability of brain after cardiac arrest in animal models are still lacking. We examined selective vulnerability of five brain regions in our well-established cardiac arrest model in pigs. Using light and electron microscopic techniques in combinations with immunohistochemistry, we observed that 5, 30, 60 and 180 min after cardiac arrest results in progressive neuronal damage that was most marked in the thalamus followed by cortex, hippocampus, hypothalamus and the brain stem. The neuronal damages are largely evident in the areas showing leakage of serum albumin in the neuropil. Furthermore, a tight correlation was seen between neuronal damage and increase in brain water content and Na⁺ indicating vasogenic edema formation after cardiac arrest. Damage to myelinated fibers and loss of myelin as seen using Luxol fast blue and myelin basic protein (MBP) immunoreactivity is clearly evident in the brain areas exhibiting neuronal damage. Upregulation of GFAP positive astrocytes closely corresponds with neuronal damages in different brain areas after cardiac arrest. At the ultrastructural level, perivascular edema together with neuronal, glial and endothelia cell damages is frequent in the brain areas showing albumin leakage. Damage to both pre- and post-synaptic membrane is also common. Treatment with methylene blue, an antioxidant markedly reduced neuronal damage, leakage of albumin, overexpression of GFAP and damage to myelin following cardiac arrest. Taken together, these observations suggest that (a) cardiac arrest is capable to induce selective neuronal, glial and myelin damage in different parts of the pig brain, and (b) antioxidant methylene blue is capable to induce neuroprotection by reducing BBB disruption. These observations strongly suggest that the model could be used to explore new therapeutic agents to enhance neurorepair following cardiac arrest-induced brain damage for therapeutic purposes.     

A case of cardiac arrest encephalopathy in athetotic cerebral palsy]

A 25-year-old woman with cerebral palsy of spastic quadriplegia and athetosis showed typical cardiac arrest encephalopathy on neuropathology. The etiology of cerebral palsy was perinatal origin including prematurity, asphyxia and hyperbilirubinemia. Ventricular premature beats had developed since about 20 years of age. Muscle tone also increased with aging and symptoms of vago-vagal reflex were occasionally observed after eating. At 25 years, cardiac arrest occurred and cardiopulmonary resucitation was done immediately. She remained unconscious with absent corneal reflex and irregular respiration. EEG or auditory brain stem response showed flat activity. She died of respiratory failure 53 days after the episode of cardiac arrest. Neuropathology showed bilaterally symmetrical necrosis in the superior colliculi, gracilis nuclei, cuneate nuclei and spinotrigeminal nuclei accompanied with severe necrosis in the cerebrum and cerebellum. These findings in this adult case of total asphyxia were compatible with those observed in total plus partial asphyxia in the neonates. This discrepancy may be due to difference in cerebral maturity. Children or young adults with athetotic type cerebral palsy have a high risk of sudden death. Sudden cardiac arrest seems to play an important role in sudden death of these patients.     

Compulsive carnival song whistling following cardiac arrest: a case study

ABSTRACT: BACKGROUND: Compulsivity is the repetitive, irresistible urge to perform a behavior, the experience of loss of voluntary control over this intense urge and the tendency to perform repetitive acts in a habitual or stereotyped manner. Compulsivity is part of obsessive-compulsive disorder (OCD), but may occasionally occur as stand-alone symptom following brain damage induced by cardiac arrest. In this case report, we describe a patient who developed compulsivity following cardiac arrest. We review diagnostic options, underlying mechanisms and possible treatments. CASE PRESENTATION: A 65-year-old man presented at our clinic with continuous compulsive whistling following cardiac arrest. Neither obsessive-compulsive symptoms, nor other psychiatric complaints were present prior to the hypoxic incident. An EEG showed diffuse hypofunction, mainly in baso-temporal areas. Treatment with clomipramine resulted in a decrease of whistling. DISCUSSION: This case report illustrates de novo manifestation of compulsivity following cardiac arrest and subsequent brain damage and gives additional information on diagnostic options, mechanisms and treatment options. Differential diagnosis between stereotypies, punding, or OCD is difficult. Compulsivity following brain damage may benefit from treatment with serotonin reuptake inhibitors. This finding enhances our knowledge of treatments in similar cases.     

Persistence of the blink reflex to sudden illumination in a comatose patient. A clinical and pathologic study

A persistent blink reflex to light (BRL) was observed in a patient who became comatose after a cardiac arrest. Postmortem examination revealed severe hypoxic ganglion cell necrosis of the cerebral and cerebellar cortex, the basal ganglia, the hypothalamus, nuclei in the brain stem, and the superior colliculi. The pretectum was unaffected. These findings suggest that the afferent fibers of the BRL enter the brain stem not in the superior colliculus, but in the pretectum.     

Protection from cerebral ischemia by brain cooling without reduced lactate accumulation in dogs

Hypothermia protects tissue function in ischemia. This study determined if selective brain cooling inhibits cerebral cortical lactate accumulation and thus accounts for imporved neurologic outcome after complete cerebral ischemia in dogs. The brain was selectively cooled (hippocampal temperature 33 degrees C) by nasal lavage with water at 5 degrees C. Control dogs received nasal lavage with water at 39 degrees C. Mean +/- SEM rectal temperature in both groups was 39 +/- 1 degree C prior to ischemia. Selective brain cooling before and during 10 minutes of cardiac arrest was associated with significantly improved neurologic function and 100% survival, whereas normothermic cardiac arrest produced marked neurologic dysfunction and 100% mortality. Cerebral cortical lactate accumulation was measured in a complementary series of dogs exposed to the same two treatments but with the addition of six cerebral cortical brain biopsies taken before, during, and immediately after cardiac arrest. Brain and rectal temperatures of dogs in the brain biopsy protocol were similar to those of dogs in the recovery protocol. There was no difference detected in cerebral lactate accumulation during ischemia between brain-cooled and control dogs. Thus, reduction in cortical brain lactate during ischemia cannot account for the postischemic functional protection afforded by preischemic selective brain cooling.     

Acute loss of psychic self-activation after cardiac arrest and delayed bilateral pallidal lesions on brain MRI

The delay between cardiac arrest and brain MRI is usually extremely different in the few cerebral imaging studies assessing the affected brain areas. We report an unusual case of loss of psychic self-activation appeared immediately after a cardiac arrest in a middle age patient. The first brain MRI, one month after the vascular event, did not show the classical lesions typically reported, such as lesion of the caudate nucleus or the globus pallidus. Two years later, although the cognitive performances of our patient were improved, a second brain MRI demonstrated bilateral pallidal lesions, suggesting a possible mechanism with delayed hypoxic lesions.     

Hypoxic-ischemic encephalopathy with cystic brain stem necroses and thalamic calcifications in a preterm twin

A severe and rare ischemic brain lesion in a preterm twin boy is reported. The boy was born after two weeks of anhydramnios and amnionic infection at 24 weeks of gestation. Following a difficult Caesarean section and prolonged umbilical cord compression he developed prenatal acidosis with an umbilical cord pH of 6.96. At the age of 7 h, heart rate variability narrowed due to severely disturbed brain stem function and the patient developed clinical signs of hypoxic-ischemic encephalopathy. Sonography demonstrated extensive symmetrical brain stem and basal ganglia lesions. After a prolonged comatose and apneic state, death occurred at the age of 25 days. Autopsy confirmed columnar bilateral cavitation of basal ganglia, diencephalon, brain stem and spinal gray matter, as well as focal calcifications in the palladium, thalamus, and brain stem. The findings highly resemble those observed after experimental or clinical cardiac arrest.     

Molecular markers of brain damage--clinical and ethical implications with particular focus on cardiac arrest

Although 25-50% of patients suffering from cardiac arrest can be stabilised haemodynamically, the hospital discharge rate is only 2-14%. One of the major causes of this discrepancy is persistent brain damage. Studies to assess the prognostic value of early prediction of neurologic and overall outcome in patients with cardiac arrest have not yet produced precise and generally accepted diagnostic rules. As apparative diagnostic methods often fail to predict neurologic outcome, the role of molecular markers has come a focus of common interest for early outcome prediction. This systematic review article aims to give an overview on the most important molecular markers for neurologic and overall outcome prediction and outline the advantages, clinical implications and ethical issues in patients undergoing cardiopulmonary resuscitation after cardiac arrest. For this purpose, the traditional marker for brain damage, the neuron-specific enolase, a gamma gamma isomer of enolase and cytoplasmatic enzyme of glycolysis, and the astroglial protein S100, a calcium-binding protein regulating neuronal differentiation, outgrowth, and apoptosis, are analysed and their role discussed as a marker for brain damage in general and recovery after cardiopulmonary resuscitation following cardiac arrest. Neuron-specific enolase has been investigated as a neuro-marker after brain damage and for outcome prediction in unconscious patients. Whereas the protein S100 has proven to be a good marker for neuronal damage after isolated brain injury, its role in cardiac surgery is not as clear: at least, in the early postoperative phase S100 is not a sole marker for neurologic damage, as release of S100 from cardiac tissue and other sources has also been demonstrated. However, the persistent elevation of S100 after cardiac surgery is specific for neurologic impairment. Most interestingly, after cardiac arrest the protein S100 has shown to be a good survival marker for overall outcome prediction. Although it cannot be absolutely determined whether cerebral or cardiac release of S100 is predominant in this clinical setting, recent studies have revealed that S100 serum levels are a useful diagnostic tool for outcome prediction. In contrast, after cardiac arrest serum levels of protein S100 did not reach a 100% specificity and sensitivity in clinical studies, and, therefore, elevated S100 in these patients has to be interpreted with caution. Nonetheless, low S100 serum levels have been correlated with good outcome and, therefore, even if all other diagnostic tests indicate poor outcome, all therapeutic efforts must be undertaken, as no single study has shown that normal S100 serum levels were associated with poor prognosis.     

Brain enzyme levels in CSF after cardiac arrest and resuscitation in dogs: markers of damage and predictors of outcome

Levels of brain creatine kinase (CK), aspartate aminotransferase (ASAT), and lactate dehydrogenase (LD) in CSF after cardiac arrest were studied in dog models. Ventricular fibrillation cardiac arrest lasting 10 min or asphyxiation cardiac arrest lasting 0-10 min was followed by cardiopulmonary resuscitation and 96-h intensive care. Outcome was scored as neurologic deficit (0% = normal, 100% = brain death) and overall performance category (1 = normal, 5 = death). Both measures correlated with EEG return time after asphyxiation cardiac arrest, but not after ventricular fibrillation cardiac arrest. Peak activity of enzymes in CSF at 48-72 h post arrest correlated with outcome, and CK was the best predictor. Brain histopathologic damage score at autopsy 96 h post arrest correlated with CK level in CSF (r = 0.79, n = 39) and neurologic deficit (r = 0.70, n = 50). Ischemic neuronal changes occurred after ventricular fibrillation cardiac arrest of 10 min, and neuronal changes plus microinfarcts occurred after asphyxiation cardiac arrest of 1.5-10 min. Brain enzymes were decreased at 6 h post arrest in regions with worst histologic damage (gray matter of neocortex, hippocampus, caudate nucleus, cerebellum). Brain CK decreased further, ASAT remained low, and LD increased at 72 h after arrest. The temporal changes in CK level paralleled the temporal ischemic neuronal changes in the brain, and time to peak activity was unaffected by the severity of the ischemic insult. Peak activity of individual enzymes in CSF was determined predominantly by the brain concentration, but was also influenced by rate of decomposition. This "chemical brain biopsy method" represents a useful adjunctive tool to predict permanent, severe brain damage during comatose states after cardiac arrest and resuscitation.     

Neuropathology of normothermic circulatory arrest in newborn dogs

Neuropathologic findings are described, for the first time, in a neonatal dog model of circulatory arrest in normothermic conditions, and the findings are compared to those reported in neonatal dogs with hypothermic circulatory arrest. Total circulatory arrest was produced in 3- to 6-day-old anesthetized, paralyzed and ventilated, normothermic dogs either by asphyxiation or cardioplegia. Duration of circulatory arrest was 8–20 min and 10–40 min in asphyxiated and cardioplegic animals, respectively. The animals were resuscitated and maintained under controlled systemic physiologic conditions until neuropathologic examination after 8 or 24 h of recovery. The results suggest that the minimal durations of circulatory arrest for brain damage to occur following asphyxia or cardioplegia are 10 and 15 min, respectively. Ischemic lesions in both groups consisted of neuronal necrosis and involved mainly the brain stem structures, particularly the reticular nuclei and the spinal cord gray matter. The medulla was more severely involved than midbrain and pons. There was a direct correlation between the length of circulatory arrest and the severity of damage in the medulla (P = 0.001) and overall brain stem damage (P = 0.004) in animals with cardioplegia, but not in animals with asphyxia. These findings are compared to the neuropathologic changes previously described in newborn dogs subjected to hypothermic circulatory arrest, in which ischemic lesions are focused on the cerebral cortex and basal ganglia. It is concluded that hypothermia in this model not only prolongs the period of circulatory arrest that is required to produce brain damage, but also shifts the pattern of regional ischemic vulnerability from caudal to more rostral structures. Received: 25 July 1996 / Revised, accepted: 29 October 1996     

On the morphogenesis of ulegyria

Summary An 11 day old premature infant survived 8 days after a cardiac arrest. At necropsy, the infant's brain showed cortical arteries surrounded by cuffs of viable neurones, while the cortex between these arteries was necrotic. This appearance suggests that the pattern of nodules of neurones separated by radial bands of scar seen in ulegyria is probably the result of healing of similar cortical infarcts, which are oligemic intracortical boundary zone infarcts occurring when the arterial vascular bed is immature.     

The CSF pressure-volume relationship before and after cardiac arrest in the cat.

The CSF pressure-volume (P-V) function was evaluated before and after cardiac arrest in 15 cats. The CSF volume change was produced by bolus loading (loading rate, greater than 0.1 mL/s) of the CSF space. Comparison of the CSF P-V function before and after cardiac arrest was made over a CSF pressure range of 5 to 46 mm Hg and for a CSF volume change of up to 9% of total CSF volume. After cardiac arrest, all CSF P-V curves were well described by the mathematical model konwn to be valid under normal physiological conditions. In eight animals, there was no significant difference between the prearrest and postarrest P-V functions. For the seven animals demonstrating a significant difference between prearrest and postarrest P-V data, all but one of the postarrest P-V curves were within the normal range. These results suggest that the shape of the CSF P-V curve is not substantially altered by cardiac arrest. We conclude that under normal circumstances material properties of brain tissue are the most important factors in determining the configuration of the CSF P-V curve and that under normal circumstances cerebral hemodynamic factors do not affect the shape of this curve.     

Thiamine and Parkinson's disease

Cardiac arrest is a leading cause of death that affects more than a million individuals worldwide every year. Despite the recent advancement in the field of cardiac arrest and resuscitation, the management and prognosis of post-cardiac arrest brain injury remain suboptimal. The pathophysiology of post-cardiac arrest brain injury involves a complex cascade of molecular events, most of which remain unknown. Considering that a potentially broad therapeutic window for neuroprotective drug therapy is offered in most successfully resuscitated patient after cardiac arrest, the need for further research is imperative. The aim of this article is to present the major pathophysiological disturbances leading to post-cardiac arrest brain injury, as well as to review the available pharmacological therapies.     

Abduction of the eyeballs palsy as a first sign of subarachnoid hemorrhage from ruptured posterior inferior cerebellar artery aneurysm: a case report

The authors present a rare case of the abduction of the eyeballs palsy caused by subarachnoid hemorrhage from ruptured posterior-inferior cerebellar artery aneurysm, which appeared as a first sign of hemorrhage. Aneurysm was clipped. During three days after the operation, oculomotor lesions appeared persistent, no consciousness deterioration or other focal signs were observed. On the third day after the operation asystolic cardiac arrest appeared. Control CT scan did not reveal any pathological changes responsible for such deterioration. The patient died. In our case after an analysis of the mechanism and pathophysiology of this lesion in our opinion that palsy might be caused by influence of extravasated blood after hemorrhage. This thesis is adequate to the reviewed literature on this problem. Nevertheless, the compression of the abducent nerve as the reason cannot be excluded, e.g. rapid enlargement of the aneurysm or the compression of the brain stem near the nerve. Posthemorrhagic lesion of the brain stem may have been the reason of this lesion, caused by penetration of the blood into the ventricle during subarachnoidal hemorrhage. Although these lesions are very rare, subarachnoid hemorrhage should be taken into consideration when the patient with eyeballs abduction palsy is admitted to a neurosurgical or neurological department.     

Supra- and infratentorial multiple cavernous angiomas in an infant: report with MR evaluation of an unusual case

A rare case of multiple cavernous angiomas with repeated hemorrhages in a 9-month-old male infant is presented, together with sequential computed tomography (CT) and magnetic resonance (MR) images. The infant underwent hematoma evacuation for left cerebellar hemorrhage, and his postoperative course was uneventful. The multiple cavernous angiomas receded gradually without any treatment except the hematoma evacuation. Two years following presentation, he continues to do well. To the authors' knowledge, this is the first report of multiple cavernous angiomas with brain stem involvement in an infant.     

Latency changes in brain stem auditory evoked potentials associated with impaired brain myelination.

Interference with myelin deposition and brain growth was produced in rats by administering p-chlorophenylalanine (PCPA), alone or with phenylalanine (PHE), from the fifth postnatal day. Treatment with PCPA + PHE until 20 days of age resulted in significantly greater developmental impairment than that produced by PCPA alone. The extent of the maturational arrest was reflected in a corresponding failure to achieve the progressive latency decrements observed in the brain stem evoked potentials of normally maturing animals. In rats treated until 30 days of age the metabolic and electrophysiologic abnormalities were attenuated. Synaptosomal content at either age and under both experimental conditions did not appear to differ from that of the control brains. Rats which received PCPA or PCPA + PHE for a brief period later in development (from 17 to 20 days of age) maintained relatively normal myelin deposition and brain growth. The latencies of their brain stem evoked potentials also remained normal despite the presence of low cerebral serotonin concentrations. These data suggst that this latency provides a general measure of brain development which seems particularly sensitive to changes in the rate of myelination.     

Vascular endothelial growth factor upregulation in transient global ischemia induced by cardiac arrest and resuscitation in rat brain

This study examined vascular endothelial growth factor (VEGF) expression in rat brain after reversible global cerebral ischemia produced by cardiac arrest and resuscitation. Three alternative splicing forms, VEGF(188), VEGF(164) and VEGF(120), were observed in cortex, hippocampus and brainstem by RT-PCR analysis. After 24 h of recovery from cardiac arrest, mRNA levels corresponding to VEGF(188) and VEGF(164) were significantly increased by about double in all the regions analyzed. These mRNA levels remained elevated at 24 and 48 h of recovery but returned to basal expression after 7 days of recovery. Changes in VEGF(120) expression after cardiac arrest did not reach statistical significance. VEGF protein expression measured by Western blot was also increased by about double at 24 and 48 h of recovery but returned to control levels after 7 days of recovery. VEGF immunohistochemistry localized this increased expression mostly associated with astrocytes. Considering its biological activity, VEGF induction after cardiac arrest and resuscitation may be responsible for the increased vascular permeability and the resultant vasogenic edema, found 24-48 h after reversible global ischemia.     

Effect of flunarizine on global brain ischemia in the dog: a quantitative morphologic assessment

The effects of flunarizine, a calcium antagonist, were evaluated in an experimental model of global brain ischemia produced by 15 min of cardiac arrest followed by resuscitation and reperfusion. One group of dogs received flunarizine (0.1 mg/kg intravenously during a 10-min period) at the onset of resuscitation. Another group of dogs underwent cardiac arrest, resuscitation, and reperfusion but did not receive flunarizine. A third group served as nonischemic control. In situ-fixed brains of all animals (nonischemic controls and the postischemic dogs after 8 h of reperfusion) were examined for anoxic ischemic injury. Quantitation of the ischemic neurons was carried out in parietal cortex, hippocampus, and cerebellum by using an image analysis system. Significant difference in the number of necrotic neurons between the flunarizine-treated group and the ischemic controls was noted in the hippocampus only; the mean percentage of necrotic neurons in the two groups being 14.8 +/- 9.6 and 29.3 +/- 12.1, respectively (P less than 0.05). These results indicate that flunarizine has an ameliorating effect on neuronal injury in the hippocampus that follows cardiac arrest in this experimental model of global brain ischemia. However, flunarizine was not found to be effective in reducing the ischemic neuronal damage in the cortex or the cerebellum.