PubMed Health⌕ Search

Biomedical subjects

C M Helgason

Publications and source records attributed to C M Helgason.

31 records · Page 2Linked to original sources
PubMed1992

Cardioembolic stroke: topography and pathogenesis.

The preventive and acute treatment of cardioembolic stroke is based upon its pathogenesis and location. Typically, cardioembolic cerebral infarction is multiple, bilateral, and often large and wedge shaped. Less frequently, smaller infarcts are produced, but the incidence of lacunar infarction or small cortico-medullary junction infarction due to cardioembolism is uncertain. Microembolism has been detected by Doppler sonography and may be constant, but the factors leading to symptomatic embolism are poorly understood. The natural lytic properties of endothelium play a role in thrombus formation in the heart and embolus lysis intracranially. In addition, site-specific tissue factors may be important in the production of complications occurring in the wake of embolic infarction: hemorrhagic transformation and edema. The treatment of cardioembolic stroke may involve prevention of both red (fibrin-based) and white (platelet-predominant) clot formation as well as a combination of clot lysis and the use of agents to prevent damage due to the final ischemic cascade after embolism has occurred. This review attempts to clarify the arterial topography, mechanism, and presentation of cardioembolic stroke.

Animals↗
PubMed1991

Basilar branch pontine infarction with prominent sensory signs.

We identified 10 patients with acute pontine infarction and specific sensory findings. Two patients had pure sensory symptoms, two had sensory complaints of the hand and mouth, and the other six had hemisensory loss referable to medial lemniscal or spinothalamic tract dysfunction but localized to one limb, to an arm and leg, or to the face, characteristic of stroke localized to the cerebral hemisphere. All patients had magnetic resonance imaging showing infarction of the medial or lateral pontine tegmentum and a patent basilar artery. No definite source for cardiogenic thromboembolism was found. Infarcts in the midline extending from the base of the pons posteriorly into the tegmentum suggested basilar branch occlusion, while infarcts involving only part of the tegmentum probably resulted from small penetrator branch occlusion. Vertigo, light-headedness, or cranial nerve dysfunction suggested a pontine location of neurological dysfunction in these patients, but the nature of the sensory findings did not always predict the lateral, medial, inferior, or superior extent of tegmental infarction.

Acute Disease↗
PubMed1990

Capsular hypesthetic ataxic hemiparesis.

Twenty-three patients with hypesthetic ataxic hemiparesis underwent computed tomography or magnetic resonance imaging. Twenty-two patients had infarcts of lacunar or slightly larger size in the contralateral posterior limb of the internal capsule. In 15 patients the infarct extended superiorly into the adjacent paraventricular region, and in seven it extended into the lateral thalmus. In eight patients the infarct was limited to the posterior limb of the internal capsule, and in only two patients was an ipsilateral to capsular pontine lacune found. Despite a location similar to that of pure motor and pure sensory lacunar stroke, hypesthetic ataxic hemiparesis correlates with larger infarcts, most often located in the posterior medial superior territory of the anterior choroidal artery. Some infarcts appeared to be localized immediately posterolateral to this region, in the posterior cerebral artery territory. The presence and extent of infarction is better detected by the addition of magnetic resonance imaging to computed tomography.

Adult↗
PubMed1990

Acute hypertensive encephalopathy in minimal change nephrotic syndrome.

A 3-year-old child with minimal change nephrotic syndrome (MCNS) developed an acute hypertensive encephalopathy characterized by coma, focal seizures, right hemiparesis, global aphasia and cortical blindness. Episodic hypertension and seizures persisted for 24 h despite intervention with antihypertensive and anticonvulsant therapy. Clinical suspicion of cortical blindness was confirmed by visual-evoked potential studies. CT scans performed 14 and 21 days after the acute episode demonstrated symmetric occipital white matter lucencies compatible with ischemia and/or associated edema. Hypertensive encephalopathy with cortical blindness and symmetric white matter hypodense lesions visualized on CT scan have recently also been described in eclampsia of pregnancy. This report documents an unusual acute hypertensive encephalopathy in childhood MCNS, unassociated with membranoproliferative glomerulonephritis, or progressive focal glomerulosclerosis.

Blindness↗
PubMed1989

The potential role for ultrafast cardiac computed tomography in patients with stroke.

We studied 40 patients with stroke of potential cardioembolic origin by cardiac ultrafast computed tomography and two-dimensional echocardiography. Cardiac ultrafast computed tomography was more sensitive (positive in eight of 14 instances) than two-dimensional echocardiography (positive in two of 14 instances) for the detection of intracardiac thrombus, which was found in 13 patients. Mitral anular calcification was diagnosed more often by two-dimensional echocardiography (four of five instances) than by cardiac ultrafast computed tomography (one of five instances); this implies a high incidence of false-positives for the former. Cardiac ultrafast computed tomography showed that one half of the patients (21 of 40) had coronary artery calcification, indicating a high incidence of coronary atheroma in this patient population. Future studies comparing brain and cardiac pathology with the findings of cardiac ultrafast computed tomography and patient prognosis are needed to define the significance and utility of this technique in patients with stroke.

Adolescent↗
PubMed1989

Neurologic manifestations of cardiac disease.

Although much has been written on the response of the heart to various intracerebral events including seizures, ischemia, intracerebral, and subarachnoid hemorrhage, less is known of the cerebral response to altered cardiac rhythm, cardiac failure, and cardiac arrest. The latter may alter central neuronal activity, cerebral blood flow, or cause ischemic damage. Such changes in cerebral function may lead to loss of consciousness, seizures, and focal neurologic deficits at the clinical level.

Brain Diseases↗
PubMed1988

A new view of anterior choroidal artery territory infarction.

Infarction in the territory of the anterior choroidal artery (AchA) has been the subject of several recent reports. To the classical clinical syndrome of hemimotor, hemisensory, and visual field deficit has been added hemiataxia acute pseudobulbar mutism, pure motor and pure sensory syndromes and disorders of higher cortical function. The definition of anatomic and clinical correlates to AchA stroke is aided by CT-MRI findings and reveals an unexpected superior extension of infarct to include the periventricular caudate nucleus and inferior corona radiata. Prognosis depends upon unilaterally, bilateral strokes having often a fatal outcome. Etiology and treatment may be intimately related to hypertension.

Brain↗
PubMed1987

Symptoms of amaurosis fugax in atherosclerotic carotid artery disease.

Amaurosis fugax is a term used to describe transient monocular visual loss due to atherosclerosis of the ipsilateral internal carotid artery. It is differentiated from other causes of transient monocular blindness, especially retinal migraine. It is said that amaurosis fugax episodes are short in duration and only occasionally include "positive" visual phenomena such as scintillations. Monocular migraine is more prolonged and often accompanied by scintillations. We studied 37 patients with amaurosis fugax and angiographic evidence of carotid atherosclerosis ipsilateral to the symptomatic eye. Nearly one-third of the patients had long attacks or positive visual phenomena. In many patients, transient monocular visual loss due to carotid atherosclerosis cannot be differentiated from retinal migraine based on clinical symptoms alone.

Adult↗
PubMed1987

Commentary on the significance for modern neurology of the 17th century B.C. Surgical Papyrus.

A 17th century B.C. Surgical Papyrus known as "The Edwin Smith Papyrus" was published in facsimile and hieroglyphic transliteration with translation and commentary by James Henry Breasted in 1930. The Papyrus was acquired by Edwin Smith in Luxor, 1862. This document was conceived in the Pyramid Age (3000-2500 B.C.) and remains in material form from the 17th century B.C. It is of importance to the history of Neurology as it contains the earliest mention in oriental literature of (a) the brain and meninges (b) calvarial and cervical vertebral injuries in details of pathology, symptomatology, treatment and prognosis and (c) functional localization in the brain and spine. Most importantly, Papyrus Smith is a statement of the medical ethic of its time.

Brain Injuries↗
PubMed1985

Circulating autoantibodies to the 200,000-dalton protein of neurofilaments in the serum of healthy individuals.

There is substantial evidence that human serum contains antibodies to many autoantigens. For example, all healthy people have autoantibodies (immunoglobulin M) to some undefined brain antigens. In this study immunoblots and immunohistochemical staining were used to detect antibodies to neural tissues in serum samples from 200 healthy people and 200 patients with various neurological diseases. Ninety-nine percent of the 400 subjects had serum immunoglobulin M and 95 percent had immunoglobulin G that bound to a 200-kilodalton protein in homogenates of neural tissues. In most cases there were no antibodies to anything else in the homogenates. The 200-kilodalton protein was the heaviest of the neurofilament triplet proteins. These observations do not support a role for antibodies to the 200-kilodalton protein of neurofilaments in the pathogenesis of neurological diseases.

Autoantibodies↗
PubMedDate not supplied

Neuroanatomic correlations with the late waves of the brain-stem auditory evoked potential.

The goal of this study was to investigate the neuroanatomic correlations of the late waves (VI-VIII) of the BAEP. Patients (N = 55) with clinical evidence of a CVA were compared to a normal control group (N = 85). Latencies of greater than 3 S.D. from the means of the normal group were considered abnormal. CT and MRI scans provided evidence of the lesions. For the 14 patients who had normal BAEPs, the sizes of lesions were significantly smaller than for those with abnormal tests. Evidence shows that an abnormal wave VI was related to an ipsilateral cortical lesion and an abnormal wave VIII was related to a lesion in the internal capsule-corpus striatum.

Adult↗
PubMedDate not supplied

Infarction after surgery for focal epilepsy: manipulation hemiplegia revisited.

The success of surgery for seizure focus resection depends on postoperative reduction or disappearance in number of seizures, improvement in psychosocial functioning, and low morbidity and mortality. Permanent neurologic sequelae are most often not discussed in this context. Deficits more than a superior quadrantanopsia are not expected after temporal lobectomy. Four cases of ischemic stroke after seizure focus resection, each distant from the site of tissue removal, are reported. These are the first such radiologically documented reports of "manipulation hemiplegia." The permanent neurologic deficits are not attributed to resected tissue or edema.

Adolescent↗