Showing papers by "Werner Hacke published in 1994"

Sensitivity and prognostic value of early CT in occlusion of the middle cerebral artery trunk.

Abstract: PURPOSE To investigate the incidence and prognostic value of local brain swelling, the extent of parenchymal hypodensity, and the hyperdense middle cerebral artery sign as shown by CT within the first 5 hours after the onset of symptoms in patients with angiographically proved middle cerebral artery trunk occlusions. METHODS Fifty-three patients were studied prospectively with CT 46 to 292 minutes (median, 120; mean, 134 +/- 59) after symptom onset and scored clinically at admission and 4 weeks later. All patients were treated with recombinant tissue plasminogen activator (30 to 100 mg). RESULTS Early CT showed parenchymal hypodensity in 43 patients (81%), local brain swelling in 20 patients (38%), and hyperdensity of the middle cerebral artery trunk in 25 patients (47%). Hypodensity covering more than 50% of the middle cerebral artery territory had an 85%, local brain swelling a 70%, and the hyperdense middle cerebral artery sign a 32% positive predictive value for fatal clinical outcome. Specificity of these findings for fatal outcome was 94%, 83%, and 51%, respectively, and sensitivity was 61%, 78% and 44%, respectively. CONCLUSIONS Early CT in acute middle cerebral artery trunk occlusion is highly predictive for fatal clinical outcome if there is extended hypodensity or local brain swelling despite aggressive therapeutic attempts such as thrombolysis or decompressive surgery.

Intensive Care of Acute Ischemic Stroke

Abstract: This survey summarises some aspects of critical-care treatment of acute ischemic stroke. Special emphasis is put on the management of raised intracerebral pressure, the use of thrombolytic therapy, ge

Modification of platelet aggregation by leukocytes in acute ischemic stroke.

Abstract: Background and purpose Platelet aggregation plays an important role in the pathogenesis of thromboembolic cerebrovascular disease. Leukocytes can efficiently stimulate as well as inhibit platelet aggregability. We studied the influence of leukocytes on collagen-induced platelet aggregation in patients with acute ischemic stroke. Methods We investigated 23 patients within 2 days after stroke and 23 healthy age- and sex-matched control subjects and determined collagen-induced platelet aggregation in platelet-rich plasma with or without addition of polymorphonuclear or mononuclear leukocytes. Results Platelet aggregation without leukocytes tended to be lower in patients than in control subjects (P = .06). Mononuclear leukocytes reduced (P = .018) and polymorphonuclear leukocytes tended to reduce (P = .06) platelet aggregation in patients. Leukocytes did not significantly alter platelet aggregation in control subjects. In the presence of either mononuclear or polymorphonuclear leukocytes, platelet aggregation was significantly lower in patients than in control subjects (P = .004 and P = .008). The ratio of polymorphonuclear leukocytes to platelets in venous blood was higher in patients than in control subjects (P Conclusions Mononuclear--and less clearly polymorphonuclear-leukocytes possess a platelet aggregation-inhibiting potential in the early stages after ischemic stroke, a feature with possible antithrombotic effects.

MRI in acute cerebral ischaemia: perfusion imaging with superparamagnetic iron oxide in a rat model

Abstract: An imaging technique capable of detecting ischaemic cerebral injury at an early stage could improve diagnosis in acute or transient cerebral ischaemia. We compared the ability of superparamagnetically contrastenhanced MRI and conventional T2-weighted MRI to detect ischaemic injury early after unilateral occlusion of the middle cerebral artery in 12 male Wistar rats. Permanent vessel occlusion was achieved by a transvascular approach, which has the advantage of not requiring a craniectomy. At 45–60 min after the procedure, the animals had conventional T2-weighted MRI before and after administration of a superparamagnetic contrast agent (iron oxide particles). Unenhanced images were normal in all animals. After administration of iron oxide particles, the presumed ischaemic area was clearly visible, as relatively increased signal, in all animals; this high signal area corresponded to the area of ischaemic brain infarction seen on histological studies. Magnetic susceptibility effects of iron particles cause low signal in normally perfused cerebral tissue, whereas tissue with reduced or absent blood flow continues to give relatively high signal. Our results suggest that superparamagnetic iron particles may significantly reduce the interval between an ischaemic insult and the appearance of parenchymal changes on MRI.

Laser Doppler flowmetry of focal ischaemia and reperfusion in deep brain structures in rats.

Abstract: Monitoring cerebral blood flow during focal ischaemia and reperfusion with established techniques such as hydrogen clearance and autoradiography is difficult. Laser Doppler flowmetry is a new technique, it allows one to continuously measure blood flow in small tissue samples. The objective of this study was to compare laser Doppler flowmetry with hydrogen clearance using a new single fiber probe to obtain measurements in deep brain structures and then to show the temporal profile of cerebral blood flow during focal ischaemia and after reperfusion.

General Therapy of Acute Ischemic Stroke

Abstract: Precise strategies of therapeutic management following acute cerebrovascular occlusion are still lacking. Earlier therapeutic studies have had major methodological limitations, and in most instances patients have been treated too late. In addition, since many of the studies were planned and performed in the pre-computed tomography (CT) era, different subtypes of stroke could not be accurately distinguished. Even in the last decade, studies have been performed in which no CT was required and patients were entered into the study 24 h after stroke onset or even later. Today most stroke investigators agree that the optimal time window for treatment of patients with acute brain infarction is less than 8 h, perhaps less than 2 h in some cases. Enthusiasm for immediate treatment has developed during the past few years, including enthusiasm for an intensive care unit (ICU)-type management approach for selected subtypes of acute stroke.

Other Viral Infections

Abstract: Infection of the central nervous system by enteroviruses (EV) is of major epidemiological importance. About half of the annual 40 000–60 000 cases of aseptic meningitis and up to 10% of probably 20 000 cases of encephalitis in the US are likely to be caused by an EV agent, mainly Coxsackie or entero cytopathogenic human orphan (ECHO) viruses (Table 1). Usually, only a few viral strains dominate the regional incidence at a given time (i.e., 15% of strains cause more than 80% of cases). Subclinical infection is common worldwide for all subtypes and there is immunity against a particular virus after infection in immunocompetent hosts.

Acute Disseminated Encephalomyelitis (Parainfectious and Postvaccinal Encephalitis)

Abstract: Acute disseminated encephalomyelitis (ADEM) is an autoimmune inflammatory demyelinating disease of the central nervous system. It may follow a viral infection, Mycoplasma and bacterial infection, or immunization. The most common viruses associated with ADEM are measles, rubella, and varicella zoster. ADEM is usually a monophasic illness, but some patients may have a fulminating, progressive, or relapsing course. Histopathology shows multifocal, perivascular (mostly perivenous) lymphocytic inflitration, demyelination, and focal necrosis infrequently associated with hemorrhage. The demyelinated plaques are usually smaller than those found in multiple sclerosis (MS).

Therapeutic hypothermia after cerebral ischemia. Theoretical principles and possible clinical applications

Abstract: In animal models of cerebral ischemia hypothermia has been shown to have a beneficial effect. Reduction of infarct size, fewer potentially neurotoxic metabolites, and a better neurological outcome were observed compared to sham-operated animals. In clinical practice hypothermia has been widely used in cardiovascular surgery and occasionally in neurosurgery. The first trials with hypothermia in patients with severe head injury have also shown beneficial results. However, studies on therapeutic hypothermia in the clinical management of acute stroke are not yet available.

Vertebrobasilar Stroke, Cerebellar Stroke, and Basilar Occlusion

Abstract: This chapter is concerned mainly with “major” and life-threatening ischemic strokes in the posterior circulation. There is a rough correlation between the clinical severity of brain-stem strokes and the presence of large artery occlusive disease in the vertebrobasilar system. Small penetrating vessel or branch arterial disease results in restricted brain-stem and cerebellar infarcts with a relatively good functional prognosis and will not be the main focus of this discussion.

Prognostic Significance of Evoked Potentials in Acute Basilar Occlusion

Abstract: ObjectiveTo establish valid prognostic parameters in patients with acute basilar artery occlusive disease. DesignA prospective study. SettingNeurocritical care unit at the University of Heidelberg. PatientsTwenty-three patients (12 male, 11 female; 32 to 69 yrs of age, median 54) with acute basilar occlusions. InterventionsAngiography, brainstem auditory and somatosensory evoked potentials. Measurements and Main ResultsClinical and electrophysiologic data were obtained before angiography and thrombolytic therapy. Outcome was classified according to a slightly modified Glasgow Outcome Scale at discharge from the intensive care unit (ICU).Level of consciousness was determined in four classes: awake (n = 4); somnolence (n = 7); stupor (n = 4); and coma (n = 8).Bilateral recordings of brainstem auditory and somatosensory evoked potentials were ranked in three categories: normal; one side normal; and both sides abnormal. Of 23 sets of evoked potential recordings, brainstem auditory evoked potentials were normal in seven patients, one side abnormal in four patients, and both sides abnormal in 12 patients. Somatosensory evoked potentials were normal in eight patients, one side abnormal in eight patients, and both sides abnormal in seven patients. A combination of both evoked potential modalities demonstrated normal results in three patients, one side abnormal recordings in six patients, and both sides abnormal findings in 14 patients.Outcome was ranked in three groups: five individuals had a good recovery or moderate disability; two patients remained severely disabled; and 16 patients persisted either in a locked-in state or died. Statistical analysis using Fisher's exact test demonstrated a significant correlation between the initial brainstem auditory evoked potential findings and outcome (p < .005), while for the initial somatosensory evoked potentials a significant correlation with outcome was not identified (p = .089). All patients with normal brainstem auditory and somatosensory evoked potential findings did well, whereas all patients with bilateral (both sides) abnormal brainstem auditory evoked potential and bilateral abnormal somatosensory evoked potential remained locked-in or died. ConclusionInitial brainstem auditory evoked potential and somatosensory evoked potential testing are valid prognostic parameters on which to base therapeutic decisions in patients with acute basilar occlusion. (Crit Care Med 1993; 21:1169–1174)

The Comatose Patient

Abstract: Impairment of consciousness and coma are important problems in neurocritical care. The ascending reticular activating system (ARAS) exerts the most influence on consciousness and any damage to this system, either directly or indirectly, impairs consciousness. Consciousness Is defined as the state of awareness of one’s self and the environment. Coma is the opposite of consciousness and is the total absence of awareness of one’s self and the environment, even when externally stimulated.

Special Aspects in the Treatment of Severe Hemispheric Brain Infarction

Abstract: While respiratory, cardiac, nursing, nutritional, and rehabilitative management are critical in determining outcome in many patients with acute stroke, it is the emergence of several new direct treatment strategies for brain ischemia that has rekindled interest in the intensive management of acute stroke. Because there has been no proven treatment strategy available, a fatalistic or even nihilistic attitude towards acute stroke management has evolved in the medical and general communities. Patients are often admitted for “observation”, “supportive care”, or “physical therapy”. In the past, the major immediate treatment decision often revolved around acute anticoagulation with heparin, and anticoagulation frequently was not started until worsening had actually occurred in hospital. Therapeutic trials of new agents used patient entry times exceeding 24 h from onset, and several studies indicated that only a minority of patients present to their local emergency room within the first several hours after stroke onset. Upon arrival at the hospital there are frequent logistical delays, such as obtaining brain imaging, which impede prompt initiation of therapy. Since the therapeutic window in most patients with evolving brain infarction is probably less than 8 h, perhaps as brief as 2 h in some cases, such delays are not acceptable and must be overcome through aggressive educational programs. The NINDS thrombolytic trial in acute stroke has employed novel quality-management techniques to accelerate patient flow upon arrival at hospital.

Doppler Ultrasound Monitoring

Abstract: Due to its unique temporal resolution in the range of milliseconds, Doppler ultrasound has become one of the clinically and scientifically most fruitful and innovative noninvasive techniques for the investigation of the cerebral circulation. This refers to extracranial continuous-wave Doppler sonography (ECD) of the extracranial brain arteries, transcranial Doppler sonography of the large basal intracranial brain arteries, and transcranial color-coded Duplex scanning (TC-Duplex) with low-frequency (approximately 2 MHz) pulsed ultrasound. Particularly, transcranial Doppler sonography (TCD) has a great impact on ultrasound monitoring in neurocritical care. It can be administered as frequently and for as long as desired. With simple provocative stimuli, it also permits a number of functional tests of the cerebral circulation. TCD provides a quantitative estimate of the true blood flow volume. Mean flow velocity of the blood column, if compared intraindi-vidually, closely reflects the true volume flow when compared with electromagnetic or CBF measurements.

Life-Threatening Hyperthermic Syndromes

Abstract: Several neurological disorders can be caused by treatment with neuroleptic drugs, including acute and tardive dyskinesia, tremor, akathesia, and parkinsonism. Neuroleptic malignant syndrome (NMS) is the rarest and most dangerous disorder, occurring in 0.5%–0.14% of patients taking neuroleptic drugs. It is twice as common in men and 80% of patients are younger than 40 years. NMS is usually associated with regular therapeutic doses of haloperidol and fluphenazine (the most potent and most commonly prescribed neuroleptics). Previous exposure is not a prerequisite. NMS can be caused by other neuroleptics, including those used to treat nausea and vomiting, dissociative diseases, Tourette’s syndrome, Huntington’s disease, and agitation, as well as by some antidepressants. It can also result from withdrawal of dopaminergic drugs and may be identical to the malignant L-dopa withdrawal syndrome and acute akinetic crisis. In the past, death occurred in 25% of patients. The most common causes of death were pneumonia, hypotension, arrhymias, renal failure, and thromboembolism. Today, because of more widespread recognition and advances in supportive care, the mortality rate is approximately 10%.

Septic Embolic Encephalitis

Abstract: Septic embolic encephalitis (SEE) results from infectious, ischemic, and hemorrhagic damage to the neuro-parenchyma following infective thromboembolism from any part of the body. The heart is the most common source (infective endocarditis), followed by bacteremia and pulmonary infections. At autopsy, SEE is characterized by diffuse congestion and hyperemia of the leptomeninges, cerebral edema, and sometimes focal subarachnoid hemorrhage. Numerous microabscesses can be seen and occasionally they coalesce to form space-occupying macroabscesses. Vessel occlusion by thromboemboli and bacterial vasculopathy (including septic erosion of the vessel wall) can result in cerebral ischemia, intracerebral hemorrhage, or both. Evaluation and treatment of septic embolic encephalitis in the neurocritical care unit requires an interdisciplinary approach.

Standard Management and Prophylaxis

Abstract: This chapter reviews standard management protocols for patients with acute neurological diseases and may serve as a brief summary for physicians in the emergency department or in the neurocritical care unit. Most of the topics described are discussed in detail in other chapters.

HIV Infection and Associated Opportunistic Infections

Abstract: Neurological involvement is a major problem in HIV patients. More than half of the patients may develop one or more neurological complications. Ten percent of patients will have a problem affecting the nervous system at initial presentation. It is often possible to effectively treat these patients as outpatients; however, it is occasionally necessary to administer care in an intensive care unit (ICU). Often those patients suffer from additional internal complications, e.g. Pneumocystis carinii pneumonia or generalized cytomegalovirus infection and therefore need interdisciplinary intensive care.

Intracranial Pressure Monitoring

Abstract: Recognition of the unique nature of the cranial contents and the motivation for monitoring the pressure in the cranium can be traced back to 1783 and Alexander Monro (Secundus)’ monograph, “Observations on the Structure and Functions of the Nervous System” Monro writes: For being enclosed in a case of bone the blood must be continually flowing out of the veins, that room may be given to the blood which is entering by the arteries For as the substance of the brain, like that of other solids of our body, is nearly incompressible, the quantity of blood within the head must be the same, or very nearly the same, at all times, whether in health or disease, in life or after death, those cases only excepted in which water or other matter is effused, or secreted, from the blood vessels; for in these, a quantity of blood, equal in bulk to the effused matter, will be pressed out of the cranium

Confusion, Psychosis, and Neuropsychological Symptoms

Abstract: The phenomena described in this chapter are assessed exclusively on the basis of observing the patient’s spontaneous behavior, talking to him and listening to him. Ancillary examinations are of little help. This is a field intermediate between neurology and psychiatry. Doctors who are uncertain about terminology and classification should take great care to describe in as much detail as possible what they have observed personally and what they have learned about the patient’s behavior from nurses and relatives. A correct and vivid description will eventually permit the diagnosis.

Sleep Apnea Syndrome and Other Ventilatory Disturbances

Abstract: Sleep apnea syndrome is characterized by recurrent cessations or substantial reductions of airflow in nose and mouth during sleep. In some patients the cessations (apneas) or reductions (hypopneas) occur because the upper airway is repeatedly sucked closed with inspiratory effort during sleep. In others, airflow may be reduced because of decreased ventilatory effort. Apneas and hypopneas with decreased or absent ventilatory effort are called non-obstructive or central, those with ongoing substantial effort obstructive. Sometimes, during an apnea there is initially no ventilatory effort, but then as the apnea continues ventilatory effort occurs before airflow resumes. This third type of apnea is called mixed. Often, patients with sleep apnea syndrome have more than one type of apnea. Commonly, both apneas and hypopneas occur in the same patient during a typical sleep period. Hypoxia, hypercarbia, or increased ventilatory effort alone trigger arousals and associated resumptions of air flow. These arousals, even when they last only a few seconds, disrupt sleep architecture, contributing to the nonrestorative quality of sleep in patients with sleep apnea syndrome.

Acute Visual Loss — Monocular Blindness

Abstract: Acute monocular blindness is usually caused by vascular disease or trauma. Less common causes include space-occupying lesions, vascular malformations, or inflammatory processes. These can be differentiated mainly by the different time course of the visual loss (Fig. 1).

General Assessment and Care of the New Patient

Abstract: Advances in the diagnosis and treatment of neurological disease have recently led to a dramatic increase in neurocritical care units. As most patients with acute life-threatening neurological diseases have systemic disease, the critical care unit facilitates an interdisciplinary approach to patient care that involves neurology, neurosurgery, anesthesiology, and internal medicine. Patients should receive neurocritical care if they have signs of increased intracranial pressure, coma, or neurological disease associated with respiratory or cardiovascular failure. Other patients who may benefit from neurocritical care include those with subarachnoid hemorrhage (all grades), space-occupying hemorrhage or stroke, meningitis, encephalitis, status epilepticus, and progressive muscular weakness (especially involving the respiratory muscles; Table 1). Patients receiving thrombolytic therapy and plasmapheresis or those undergoing interventional neuroradiological procedures may also benefit from neurocritical care (high- or low-acuity monitoring).

Neck Stiffness and Headache

Abstract: Neck stiffness and headache are important features of various disorders presenting as neurological or neurosurgical emergencies. Their simultaneous appearance usually reflects meningeal irritation and together with accompanying signs and symptoms is of significant diagnostic value.