Unexpected death during a brain scintigraphy

Brain scintigraphy was performed for differential diagnosis of suspected subdural hemorrhage in a 79-year-old woman. Planar pertechnetate (99mTcO4-) brain scan with AP, PA, lateral and vertex projections was planned. The procedure was started with AP-projection, continuing with lateral projections. After these images the patient was determined dead and the planned scannings were aborted. There was a clear difference in the intracranial uptake (choroid plexuses) in the lateral views as well as in the uptake in the venous sinuses. The findings in the AP view were normal and no signs of subdural hemorrhage were observed. The patient died during a routine nuclear medicine procedure, and cessation of intracranial circulation was observable on 99mTcO4- scans; the lack of uptake in cerebral sinuses confirmed the lack of intracerebral flow. In this rare case, brain death could be timed accurately using a static nuclear medicine procedure. Autopsy confirmed sudden brain circulatory disorders and general arteriosclerosis.     

Fatal cerebral gunshot wounds: factors influencing organ donation

Patients with clinical brain death following head injury are important potential cadaveric organ donors. We analyzed our series of cranial gunshot wounds with particular attention to the frequency and patterns of organ donation after fatal injuries. Sixty-six patients with gunshot wounds to the head, including 59 with intracranial involvement (43 male, average age 26 years) were seen during a 4-year period. Injuries were limited to the head in 50 of 59 patients. Overall mortality was 66 per cent. Predictors of mortality included Glasgow Coma Scale (GCS) of six or less (93%), self-inflicted gunshot wounds (75%), and computed tomography (CT) findings of bihemispheric injury (87%) or ventricular injury (82%). Of the 39 patients who died, 28 met standard criteria for brain death, and nine of these went on to organ procurement. Thirteen families refused donation, and six patients were not harvested for reasons including old age, pregnancy, suspicion of AIDS, coroner refusal, and failure to pursue consent. Principles essential to maximal organ retrieval include: 1) Recognition that patients suffering cerebral gunshot wounds represent potential organ donors and that certain factors are predictive of mortality; 2) Critical care/trauma team approach with standardized management and timely declaration of brain death; 3) Early search for family members and prompt notification of organ procurement agencies; 4) Sensitivity to cultural issues influencing donation; and 5) Programs to increase public awareness of organ donation.     

A comparison of the perioperative neurologic effects of hypothermic circulatory arrest versus low-flow cardiopulmonary bypass in infant heart surgery

BACKGROUND: Hypothermic circulatory arrest is a widely used support technique during heart surgery in infants, but its effects on neurologic outcome have been controversial. An alternative method, low-flow cardiopulmonary bypass, maintains continuous cerebral circulation but may increase exposure to known pump-related sources of brain injury, such as embolism or inadequate cerebral perfusion. METHODS: We compared the incidence of perioperative brain injury after deep hypothermia and support consisting predominantly of total circulatory arrest with the incidence after deep hypothermia and support consisting predominantly of low-flow cardiopulmonary bypass in a randomized, single-center trial. The criteria for eligibility included a diagnosis of transposition of the great arteries with an intact ventricular septum or a ventricular septal defect and a planned arterial-switch operation before the age of three months. RESULTS: Of 171 patients with D-transposition of the great arteries, 129 (66 of whom were assigned to circulatory arrest and 63 to low-flow bypass) had an intact ventricular septum, and 42 (21 assigned to circulatory arrest and 21 to low-flow bypass) had a ventricular septal defect. After adjustment for diagnosis, assignment to circulatory arrest as compared with low-flow bypass was associated with a higher risk of clinical seizures (odds ratio, 11.4; 95 percent confidence interval, 1.4 to 93.0), a tendency to a higher risk of ictal activity on continuous electroencephalographic (EEG) monitoring during the first 48 hours after surgery (odds ratio, 2.5; 95 percent confidence interval, 1.0 to 6.4), a longer recovery time to the first reappearance of EEG activity (only in the group with an intact ventricular septum, P < 0.001), and greater release of the brain isoenzyme of creatine kinase in the first 6 hours after surgery (P = 0.046). Analyses comparing durations of circulatory arrest produced results similar to those of analyses comparing treatments. CONCLUSIONS: In heart surgery in infants, a strategy consisting predominantly of circulatory arrest is associated with greater central nervous system perturbation in the early postoperative period than a strategy consisting predominantly of low-flow cardiopulmonary bypass. Assessment of the effect of these findings on later outcomes awaits follow-up of this cohort.     

Natural history of global and critical brain ischaemia. Part II: EEG and neurological signs in patients remaining unconscious after cardiopulmonary resuscitation

Of 125 patients who had no detectable cortical activity (DCA) on the electroencephalograph (EEG) immediately upon resuscitation from circulatory arrest of primary cardiovascular aetiology, 88 remained unconscious; these patients had their EEG and neurological status serially investigated until they died. Immediately upon re-establishment of circulation all cerebral functions could be absent; the brain death (irreversible loss of functions) was then signified by the appearance of poikilothermia, diabetes insipidus and reflex extension of the upper limb. Most often, some cranial nerve reflexes were present; the EEG configurations and related neurological signs then appeared in a sequence which resembled orderly postischaemic recovery: A phase without DCA was at first characterized by an exclusive presence of cranial nerve reflexes and then by the appearance of decerebrate posturing this phase was followed by another phase of intermittent cortical activity (ICA) with decorticate and stereotypic motor responses and a phase of continuous cortical activity (CCA) accompanied by stereotypic reactivity. These phases were most often incomplete due to failure of recovery of some cranial nerve reflexes or were abnormal due to the appearance of intermittent spikes and sharp waves. Progressive recovery could stagnate at any step and the cerebral functions be lost abruptly or gradually in reverse order of recovery. The decay was invariably due to cardiovascular or pulmonary complications. Brain autopsy revealed extensive neuronal loss and intravital autolytic changes in patients who had fulfilled clinical criteria of brain death for more than 72 h, but the histopathology showed no relationship to other clinical findings during the postischaemic course.     

Role of permanent stents

Brain dead patients are ideal donors for organ transplantation. The lack of organs has aroused new interest in other kinds of patients who are called non-heart-beating donors. In these donors the warm ischaemia time should be as short as possible. This problem has led to a discrepancy between a proper diagnosis of death and a fast organ procurement. In non-heart-beating donor protocols the death should be determined in an unambiguous manner that can also be accepted in other situations. The best solution would be to create one set of criteria of death that can be applied to all situations. Brain death as the criterion of death also in patients with asystole would serve this purpose.     

Effects of induced hypertension on transcranial Doppler ultrasound velocities in patients after subarachnoid hemorrhage

BACKGROUND AND PURPOSE: Transcranial doppler ultrasound (TCD) is used after subarachnoid hemorrhage to detect cerebral vasospasm and is often treated with induced hypertension. Cerebral autoregulation, however, may be disturbed in this population, raising the possibility that TCD velocities may be elevated by induced hypertension. To study this possibility, we performed continuous TCD monitoring of the middle cerebral artery during the induction and withdrawal of induced hypertension in patients after subarachnoid hemorrhage. METHODS: Twenty-eight patients were studied during the induction and withdrawal of hypertension using primarily phenylephrine. Continuous monitoring was performed on the middle cerebral artery with the highest flow velocity. Treatment was based on rising TCD velocities or clinical evidence for cerebral vasospasm. Mean arterial pressure and mean TCD velocities were recorded every minute. A change of > 15% from starting TCD values was considered significant. Cerebral autoregulation was calculated as a percentage of intact autoregulation. Patients were subsequently divided into groups of disturbed and intact autoregulation. RESULTS: In 10 of 19 patients (53%), TCD velocities changed by > 15% and paralleled changes in mean arterial pressure. This directly altered the TCD interpretation of the grade of vasospasm in 7 of 19 patients (36%). Three additional patients had smaller absolute changes in TCD velocities. No clinical difference could be identified between patients with disturbed and intact autoregulation. CONCLUSIONS: In patients with disturbed autoregulation after subarachnoid hemorrhage, induced hypertension can alter cerebral blood flow velocities. The level of autoregulation needs to be considered when interpreting TCD velocities in patients after subarachnoid hemorrhage.     

Neuron-specific enolase concentrations in blood as a prognostic parameter in cerebrovascular diseases

BACKGROUND AND PURPOSE: To investigate the clinical relevance of plasma concentrations of neuron-specific enolase (NSE) in patients with severe cerebrovascular diseases, serial analyses were performed during the first 10 days after the acute event. METHODS: Plasma samples taken from 61 patients (30 with brain infarction, 13 with intracerebral hemorrhage, 11 with cardiogenic hypoxia-ischemia, and 7 with myocardial infarction [as control group]) were analyzed for NSE concentration using an enzyme immunoassay. The time course of plasma NSE was correlated with clinical findings, clinical outcome, cranial computed tomography, intracranial pressure, and other laboratory data. RESULTS: In cases of hypoxia-ischemia there was close correlation between plasma NSE values during the first 72 hours and the clinical outcome. In brain infarction and intracerebral hemorrhage, high plasma NSE mostly indicated an unfavorable outcome, but low values did not permit a reliable prognostic estimation. In cases of cerebral infarction and intracerebral hemorrhage with secondary neuronal destruction (for example, due to malignant edema), increasing NSE concentrations in plasma preceded the change of clinical or other diagnostic parameters. CONCLUSIONS: The course of plasma NSE levels is seen as a relevant parameter for assessing the prognosis of cerebral hypoxia-ischemia. Additionally, it may prove to be a useful tool for monitoring space-occupying brain infarctions and intracerebral hemorrhages and therefore may contribute to improved therapeutic management of severe cerebrovascular diseases.     

Management of subarachnoid hemorrhage patients who presented with respiratory arrest resuscitated with bystander CPR

BACKGROUND AND PURPOSE: The sudden death rate from aneurysmal subarachnoid hemorrhage (SAH) is 10%. Since 1989, 26 SAH patients who were witnessed to collapse into coma with respiratory arrest and required cardiopulmonary resuscitation (CPR) at the scene survived to reach the hospital and be diagnosed. Although reports on hospital management of grade V SAH suggest improved outcome, no report has previously addressed the issue of respiratory arrest after acute SAH. We analyze our experience with this unique subgroup of aneurysmal SAH patients. METHODS: This is a retrospective analysis of 26 consecutive SAH patients who collapsed at the scene and required CPR for respiratory arrest and survived to reach the hospital and be diagnosed. Statistical analysis was performed using the t test and Mann-Whitney rank-sum test. RESULTS: All patients were grade V on arrival at the emergency department. Twenty-one patients received mouth-to-mouth resuscitation only, and 5 received chest compressions as well. The mean duration of bystander CPR was 12 to 15 minutes. CT scan showed diffuse, thick SAH in all patients, an associated subdural hemorrhage in 2, and an intraparenchymal hemorrhage in 4. After CT scan, an intracranial pressure (ICP) monitor was placed in 24, and 2 were taken to emergency surgery for subdural and intracerebral hemorrhage. ICP was elevated in 24 patients (mean, 54 mm Hg), and a ventriculostomy was placed in all 24. ICP was unresponsive in 12, and all suffered brain death. ICP lessened to < 25 mm Hg in 12, and all underwent angiography. All 12 had an aneurysm and underwent emergency surgical clipping. Time to surgery from SAH was < or = 11 hours in all 12 patients. All were managed with calcium channel blockers and hyperdynamic therapy in addition to aggressive control of ICP. The outcome at 12 months in the 14 surgical cases was normal in 3 patients (21%), good in 2 (14%), vegetative in 1 (7%), and death in 8 (57%). CONCLUSIONS: Aneurysmal SAH patients that present with respiratory arrest present as grade V patients with elevated ICP. Bystander CPR coupled with early retrieval, diagnosis, and therapy can lead to 20% functional survival in what used to be sudden death from aneurysmal SAH.     

The use of pacemakers as treatment for systolic dysfunction

BACKGROUND AND PURPOSE: Oscillating flow or systolic spikes are typical Doppler-sonographic flow signals found in the presence of cerebral circulatory arrest, which if irreversible, results in brain death. The Neurosonology Research Group (NSRG) of the World Federation of Neurology (WFN) created a Task Force Group in order to evaluate the role of Doppler-sonography as a confirmatory test for determining brain death. METHODS: The available evidence from the literature has been reviewed and discussed by a group of experts, the members of the Task Force Group on cerebral death of the NSRG. RESULTS AND CONCLUSIONS: Extra- and intracranial Doppler-sonography is a useful confirmatory test to establish irreversibility of cerebral circulatory arrest as optional part of a brain death protocol. Doppler-sonography is of special value when the therapeutic use of sedative drugs renders electroencephalography unreliable. Doppler-sonographic criteria are defined and guidelines for the use of Doppler-sonography in this setting are presented.     

A new perspective on the relationship between communication impairment and disempowerment following head injury in information exchanges

Transcranial doppler sonography is a diagnostic tool that allows the noninvasive study of intracranial circulation. In patients with aneurysmal subarachnoid hemorrhage, cerebral vasospasm is promptly diagnosed, even before clinical related symptoms. Feeding arteries of an arteriovenous cerebral malformation can be detected and their variations can be correlated to the treatment (neurosurgical and/or neuroradiological). When raised intracranial pressure (namely in head trauma), transcranial doppler sonography depicts vasospasm and/or typical variations of the waveforms, suggesting intracranial circulatory arrest.     

Long-term follow-up study of unruptured intracranial aneurysms

OBJECTIVE: The purpose of this study was to clarify the risk of rupture of unruptured intracranial aneurysms among large groups of patients with various underlying diseases or conditions. METHODS: A long-term follow-up study of unruptured intracranial aneurysms was performed with 360 patients who were treated conservatively during the period from April 1969 to December 1992. RESULTS: Follow-up evaluation (between February and June 1994) could be performed for 234 (65%) of the patients. The underlying diseases included multiple aneurysms with subarachnoid hemorrhage for 60 patients, cerebral infarction for 108, intracerebral hemorrhage for 27, and other diseases for 39. Single aneurysms were present in 171 patients and multiple aneurysms in 63. The mean follow-up period was 75 months (range, 3-270 mo). Of the 234 patients, 132 (56.4%) survived, 59 (25.2%) died because of other diseases, 9 (3.8%) underwent surgery, and 34 (14.5%) showed bleeding from unruptured aneurysms, which was fatal for 18 of the patients. The average annual rupture rate for all patients was 2.3% (subarachnoid hemorrhage, 3.2%; cerebral infarction, 2.2%; intracerebral hemorrhage, 3.2%; other diseases, 3.6%). There were no significant differences among the patients according to underlying disease or aneurysm site. The cumulative rate of bleeding for all patients was 20% at 10 years after diagnosis and 35% at 15 years. The cumulative probability of rupture was significantly higher for the multiple aneurysms than the single aneurysms (P < 0.001). CONCLUSION: The risk of rupture of unruptured aneurysms is high, especially for multiple aneurysms, but there are no significant differences in the risk of rupture according to the underlying disease or the aneurysm location. Radical treatment should be considered for patients with unruptured intracranial aneurysms.     

Systemic lupus erythematosus: description of a pediatric series

OBJECTIVE: To analyze possible causative mechanisms for intracranial hemorrhage after orthotopic liver transplantation. DESIGN: We conducted a retrospective survey of medical records and a case-control comparison in patients who had undergone liver transplantation during the period 1986 through 1992. MATERIAL AND METHODS: In a group of 8 patients with intracranial hemorrhage after orthotopic liver transplantation and a control series of 207 patients who had undergone liver transplantation but did not have intracranial hemorrhage, we summarized pertinent clinical and laboratory data and statistically analyzed potential risk factors for hemorrhage. RESULTS: In the eight study patients, intracerebral hematomas were located in the parietal or frontal lobe in six, the cerebellum in one, and the putamen in one. Autopsy demonstrated a Candida-associated mycotic aneurysm in one of the eight patients, and one had disseminated aspergillosis. No statistically significant differences in thrombocytopenia, hypertension, extracranial bleeding sites, or cyclosporine-related neurotoxicity were found when these patients were compared with the control series. Bacteremia or fungemia was found in five of the eight patients with intracerebral hemorrhages (62%) but in only 11% of the control group (P = 0.03; Fisher's exact test). CONCLUSION: Overwhelming infections, thrombocytopenia, or both may have a role in intracerebral hemorrhage after liver transplantation.     

Rupture during treatment of recently ruptured aneurysms with Guglielmi electrodetachable coils

BACKGROUND AND PURPOSE: We describe four cases of aneurysmal rupture during embolization with Guglielmi electrodetachable coils (GDCs) in an attempt to identify those aneurysms whose rupture during embolization represents a life-threatening risk; our emphasis is on emergency management, in particular, ventriculostomy. METHODS: Medical records were reviewed retrospectively for 91 aneurysms treated with GDCs 0 to 21 days after subarachnoid hemorrhage. Rupture was ascertained by the presence of extravascular effusion of contrast medium. RESULTS: Of the perforated aneurysms, two involved the anterior communicating artery, one the posterior inferior communicating artery, and one the basilar artery. Only two patients, whose aneurysms were located in the posterior fossa, had major complications (arterial hyperpressure, mydriasis, angiographically documented circulatory arrest or slowing). One of these patients died and the other improved after emergency ventriculostomy. CONCLUSION: Aneurysmal perforation during embolization may be accompanied by severe intracranial hypertension, which causes either a decrease or arrest of cerebral perfusion, the duration of which determines clinical outcome. Emergency ventriculostomy (which should be performed in the angiographic suite) is an effective means to reduce intracranial pressure. Recognition of aneurysms associated with a high risk of mortality by rupture in the course of embolization (recently ruptured small aneurysms, posterior fossa aneurysms, associated ventricular dilatation, massive cisternal hemorrhage) and use of proper logistics should ensure the effective management of this devastating complication.     

Postischemic hyperthermia exacerbates neurologic injury after deep hypothermic circulatory arrest

BACKGROUND: Aggressive surface warming is a common practice in the pediatric intensive care unit. However, recent rodent data emphasize the protective effect of mild (2 degrees - 3 degrees C) hypothermia after cerebral ischemia. This study evaluates different temperature regulation strategies after deep hypothermic circulatory arrest with a survival piglet model. METHODS: Fifteen piglets were randomly assigned to 3 groups. All groups underwent 100 minutes of deep hypothermic circulatory arrest at 15 degrees C. Brain temperature was maintained at 34 degrees C for 24 hours after cardiopulmonary bypass in group I, 37 degrees C in group II, and 40 degrees C in group III. Neurobehavioral recovery was evaluated daily for 3 days after extubation by neurologic deficit score (0, normal; 500, brain death) and overall performance category (1, normal; 5, brain death). Histologic examination was assessed for hypoxic-ischemic injury (0, normal; 5, necrosis) in a blinded fashion. RESULTS: All results are expressed as mean +/- standard deviation. Recovery of neurologic deficit score (12.0 +/- 17.8, 47.0 +/- 49.95, 191.0 +/- 179.83; P = .05 for group I vs III), overall performance category (1.0 +/- 0.0, 1.4 +/- 0.6, 2.8 +/- 1.3; P < .05 for group I vs III), and histologic scores (0.0 +/- 0.0, 1.0 +/- 1.2, 2.8 +/- 1.8; P < .05 for group I vs III cortex) were significantly worse in hyperthermic group III. These findings were associated with a significantly lower cytochrome aa3 recovery determined by near-infrared spectroscopy in group III animals (P = .0041 for group I vs III). No animal recovered to baseline electroencephalographic value by 48 hours after deep hypothermic circulatory arrest. Recovery was significantly delayed in the hyperthermic group III animals, with a lower amplitude 14 hours after the operation, which gradually increased with time (P < .05 for group III vs groups I and II). CONCLUSIONS: Mild postischemic hyperthermia significantly exacerbates functional and structural neurologic injury after deep hypothermic circulatory arrest and should therefore be avoided.     

Brain death: neuropathological findings and forensic implications

'Brain death' is defined pathophysiologically as intracranial circulatory arrest. The morphological features of brain death include cerebral edema, absence of reactive changes, and--after an interval of 15-36 h--the morphological hallmarks of respirator brain: edema, global softening of the brain, dusky discoloration of the gray matter, and often necrotic and sloughing tonsillar herniations. The following implications of brain death for forensic medicine are discussed: discriminating between respirator and autolytic brain, declaration of death, determining the time of brain death versus the time of the traumatic event leading to brain death, and neuropathological control of the clinical diagnosis of brain death. These issues are elucidated and their bearing on forensic practice is illustrated by several real-life situations. Thus, neuropathological examination in the case of clinically diagnosed brain death is--without doubt--necessary in order to answer several questions often or regularly expected.     

The echocardiographic findings in patients with brain death. The implications for their selection as heart transplant donors

INTRODUCTION AND AIMS: Brain death causes myocardial impairment by some mechanisms not yet well understood. The aim of this work was to assess the echocardiographic features found in these patients and their implication in donor selection for heart transplantation. METHODS: With this aim, we have studied 38 consecutive patients with brain death assessed as possible donors for heart transplant in our hospital in the last 3 years. Age was 23 +/- 13 years; 77% were male. No history of cardiac disease was present in any patient. An adequate transthoracic echocardiogram was obtained in 74% of patients; transesophageal view was used in the remaining 26%. RESULTS: Echocardiogram was strictly normal in only 14 patients (37%). Mild valvular alterations were found in 5 patients (13%); a dilated aortic root in 1 (3%); moderate concentric left ventricular hypertrophy in 5 (14%); mild pericardial effusion in 1 (3%); mild septal hypokinesia with normal left ventricular ejection fraction in 4 (10%); abnormal left ventricular diastolic function in 7 (18%); and diffuse hypokinesia with ejection fraction less than 60% in 14 (37%). In 7 patients (18%) ejection fraction was lower than 40% (one of them was cocaine-addict). Mean ejection fraction was 59 +/- 15% (23 to 83%). Only 2 of the 19 (10%) donor hearts implanted in our hospital showed early dysfunction after transplant, but no relation to pretransplant ejection fraction was found. Ejection fraction increased from 62% pretransplant to 73% at one week after transplant in the other 17 cases. CONCLUSIONS: Brain death commonly causes alterations of left ventricular function, and this impairment is severe in almost 20% of cases. These echocardiographic features must be known when selection of donors for heart transplantation is concerned.     

Relationships between delayed ischemic dysfunctions and intracranial hemodynamics following subarachnoid hemorrhage

Delayed ischemic dysfunctions (DID) are one of the main complications following subarachnoid hemorrhage. It was the aim of our study to analyse the possible prognostic value of different transcranial Doppler ultrasonography parameters and to elucidate the risk of developing DID with particular reference to the intracranial pressure. The relative change of mean blood flow velocity and of corresponding cerebral circulatory resistance index as well as the intracranial pressure were determined in 44 patients with spontaneous subarachnoid hemorrhage. No relationship was found between the occurrence and extent of DID and the relative change of mean flow velocity during the clinical course. In contrast, there was a significant correlation between the relative change of the cerebral circulatory resistance index and the occurrence of DID. While patients without or with reversible DID showed a decreased resistance index compared to the initial value (without DID: -17% +/- 15%; reversible DID: -3% +/- 14%), patients with irreversible DID had a significant increase of the resistance index (+14% +/- 9%). Accordingly, patients with irreversible DID showed a significant increase of intracranial pressure compared to the patients with reversible DID. We conclude that the evaluation of relative changes of the cerebral circulatory resistance index by bedside monitoring is a useful tool to predict the occurrence of subarachnoid hemorrhage-associated DID and has therapeutic impact.     

Silent cerebral lesions on magnetic resonance imaging in subjects with coronary artery disease

OBJECTIVES: Critical vascular surgery of the brain or the heart occasionally requires total cessation of the circulatory system. Profound hypothermia is used to protect the brain from ischaemic injury. This study explores the use of microdialysis to measure metabolic indices of ischaemia: glutamate, lactate, and pH, and cerebral temperature during profound hypothermia and circulatory arrest. METHODS: Effluent from a microdialysis catheter placed in the cerebral cortex of three patients undergoing complete circulatory arrest was continuously sampled. Samples were pooled over 10 minute periods and glutamate and lactate concentrations were measured postoperatively. Brain temperature and pH were measured on line intraoperatively. Electroencephalography and monitoring of somatosensory evoked potentials and brainstem auditory evoked potentials were simultaneously carried out. RESULTS: Patient 1 had normal glutamate and lactate. PH was 6.75 to 6.85 and increased to 6.9 after warming ensued. Patient 2 had raised glutamate and lactate during most measurements. The glutamate concentrations peaked at 305 microM/l at the start of the measurements and fell below 20 microM/l after warming. The lactate concentrations peaked at 680 microM/l before cooling, rose to 1040 microM/l during the cooling process, decreased to 212 microM/l during circulatory arrest, and rose again to 620 microM/l after warming. The pH started at 7.06 and continued a downward course until stabilising at a pH of 6.5 after circulatory arrest. Patient 3 had a transient, mild increase in glutamate and lactate during the cooling and warming period. pH was stable throughout. CONCLUSION: Microdialysis combined with temperature and pH measurements of the cerebral cortex promises to be an important tool in detecting cerebral ischaemia. Further studies are needed to validate our findings and test the feasibility of modifying ischaemic changes.     

Intracranial hemorrhage in achondroplasia

The neurological manifestations of achondroplasia include megalencephaly, hydrocephalus, and progressive myelopathy or radiculopathy secondary to spinal stenosis. Subarachnoid and intracerebral hemorrhage have not been previously reported in association with achondroplastic dwarfism. This report describes two patients with achondroplasia who have died secondary to intracranial hemorrhage. At autopsy, the source of hemorrhage was found to be an arteriovenous malformation of the choroid plexus in one case and a ruptured aneurysm of the left middle cerebral artery in the other.