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Biomedical subjects

M C Kanter

Publications and source records attributed to M C Kanter.

9 recordsLinked to original sources
PubMed1994

Carotid stenosis in patients with atrial fibrillation. Prevalence, risk factors, and relationship to stroke in the Stroke Prevention in Atrial Fibrillation Study.

BACKGROUND: Several mechanisms contribute to the increased stroke rate of patients with atrial fibrillation (AF). We assessed the frequency of carotid artery stenosis in patients with AF and its relationship to stroke during aspirin or warfarin therapy. METHODS: Carotid ultrasonography was done in 676 patients with AF enrolled in the Stroke Prevention in Atrial Fibrillation Study to detect cervical carotid stenosis of 50% or more of the luminal diameter. The presence of carotid stenosis was correlated with patient features and subsequent stroke during a mean of 2.6 years of follow-up. RESULTS: In patients with AF who were older than 70 years, the frequency of carotid stenosis was 12% in men and 11% in women. Carotid stenosis was independently associated with systolic hypertension (relative risk, 2.4; P = .002), diabetes (relative risk, 1.8; P = .04), and tobacco use (relative risk, 1.8; P = .02). Carotid stenosis did not add significantly to prediction of stroke when analyzed with other clinical risk factors for stroke in patients with AF (relative risk, 1.3; 95% confidence interval, 0.5 to 3.6; P = .55). CONCLUSIONS: Carotid artery stenosis of 50% or more occurs in about 12% of elderly patients with AF, reflecting the substantial prevalence of hypertension and diabetes in these patients. Carotid stenosis was not usefully predictive of stroke in patients with AF who were given aspirin or warfarin. Routine ultrasonography to detect carotid stenosis does not appear warranted in patients with AF without previous symptoms of brain ischemia.

Aged↗
PubMed1993

Anterior ischemic optic neuropathy is not associated with carotid artery atherosclerosis.

BACKGROUND AND PURPOSE: The relation between anterior ischemic optic neuropathy and carotid artery atherosclerotic disease is unclear. We studied patients with anterior ischemic optic neuropathy to determine if they had an increased occurrence of carotid artery stenosis. METHODS: Fifteen consecutive patients with anterior ischemic optic neuropathy were evaluated prospectively for cervical carotid artery stenosis and compared with 30 age- and sex-matched asymptomatic patients and also with 11 age- and sex-matched patients experiencing transient monocular blindness. RESULTS: There was no difference in the mean stenosis of the internal carotid artery between patients with anterior ischemic optic neuropathy (mean carotid stenosis, 19%) and asymptomatic patients (mean carotid stenosis, 9%; p > 0.05), whereas patients with transient monocular blindness had significantly more stenosis (mean, 77%) in the cervical carotid arteries than both control subjects (p < 0.0001) and patients with anterior ischemic optic neuropathy (p < 0.0001). There was also no difference in the percentage of patients with stenosis > or = 30% in anterior ischemic optic neuropathy (two of 15) and asymptomatic patients (five of 30), whereas 10 of 11 patients with transient monocular blindness had stenoses > or = 30%, significantly more than patients with anterior ischemic optic neuropathy (p < 0.0001) and asymptomatic patients (p < 0.0001). CONCLUSIONS: Anterior ischemic optic neuropathy is not a marker for atherosclerotic carotid artery stenosis. The pathogenesis of nonarteritic anterior ischemic optic neuropathy does not involve carotid artery stenosis in most patients.

Aged↗
PubMed1993

Strategies for preventing stroke.

The limited effectiveness of any therapy for acute stroke dictates that emphasis be placed on strategies for preventing stroke. The identification and management of risk factors is paramount. Modifiable risk factors include hypertension, smoking, hyperlipidemia, and diabetes. Patients with transient ischemic attacks or stroke are at risk for recurrent stroke and should be considered for antithrombotic therapy and carotid endarterectomy. Patients with nonvalvular atrial fibrillation should also be treated with antithrombotic therapy. The proper management of other cardiac, malignant, and hematologic disorders is important in preventing stroke in these high-risk patients.

Adult↗
PubMed1991

Neurologic complications of infective endocarditis.

Neurologic syndromes often complicate the management of infective endocarditis (IE). We retrospectively reviewed 166 episodes of native valve endocarditis to assess the occurrence and implications of nonfocal encephalopathy, meningitis, salient headache, back pain, and brain abscess. Neurologic complications occurred in 35% (58/166) of patients: 41% (54/133) of mitral or aortic valve IE and 12% (4/33) of tricuspid valve IE. Of 133 cases of mitral or aortic valve IE, encephalopathy occurred in 14%, meningitis in 5%, and salient headache in 3%. All neurologic complications occurred more often with Staphylococcus aureus infection (67%) than with viridans streptococci (22%), including encephalopathy (22% versus 7%), meningitis (17% versus 0%), stroke (39% versus 16%), and death (39% versus 9%). Encephalopathy was associated with virulent organisms, increased patient age, and uncontrolled infection. Clinical, radiologic, and neuropathologic data all suggest that infective microemboli are often etiologic in IE-related encephalopathy. There were no macroscopic brain abscesses clinically identified. Meningitis occurred only with virulent organisms. While many clinical aspects of IE have changed in recent years, the frequency and gravity of neurologic complications have not.

Aortic Valve↗
PubMed1990

Acute autonomic neuropathy. Two cases and a clinical review.

Acute autonomic neuropathy is an uncommon syndrome, usually affecting healthy young people. Presentation is often dramatic and initial misdiagnosis is common. We describe two young women with acute autonomic neuropathy who presented with gastrointestinal involvement heralding widespread dysautonomia and review 26 additional cases of acute autonomic neuropathy from the English language literature. Acute autonomic neuropathy can be primarily cholinergic without orthostatic hypotension (26%) or pandysautonomic (74%) involving sympathetic adrenergic functions. Onset has been temporally related to viral syndromes in 20% of cases, with autonomic deficits usually evolving over 1 to 3 weeks. Gastroparesis (69%) and syncope (12%) are frequent presenting complaints. Spinal fluid protein levels are often (75%) elevated in pandysautonomic subtypes. Prolonged and incomplete recovery is the rule (60%), with persistent gastroparesis and orthostatic hypotension. Other specific diseases that occasionally mimic acute autonomic neuropathy include botulism, porphyria, amyloidosis, and paracarcinomatous neuropathies. Acute autonomic neuropathy shares several clinical features with acute idiopathic polyneuropathy (Guillain-Barré syndrome), suggesting an immune-mediated pathogenesis.

Acute Disease↗
PubMed1990

Stroke in infective endocarditis.

We reviewed 212 consecutive episodes of infective endocarditis in 203 patients at six hospitals between 1978 and 1986 and found that 21% were complicated by stroke. Of 133 episodes involving native mitral and/or aortic valves, brain ischemia occurred in 19%, brain hemorrhage in 7%, and non-central nervous system emboli in 11%; vegetations were identified in 56% of 113 adequate echocardiograms and did not correlate with risk of embolism. In native-valve endocarditis, most (74%) ischemic strokes had occurred by the time of presentation and an additional 13% occurred less than or equal to 48 hours after diagnosis; the incidence of brain ischemia was 13% on presentation, 3% during the first 48 hours of hospitalization, and 2%-5% during the remainder of the acute course. Stroke recurred at a rate of 0.5%/day, often heralding relapse/uncontrolled infection. Only 9% of ischemic infarcts were large (all in patients with Staphylococcus aureus infection), while 8% were small and subcortical. Brain hemorrhage occurred primarily at the time of presentation, particularly in intravenous drug abusers, and was associated with uncontrolled S. aureus infection with pyogenic arteritis. Ischemic and hemorrhagic stroke continue to be frequent and important in patients with infective endocarditis and are clustered during uncontrolled infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Hematologic disorders and ischemic stroke. A selective review.

More than a dozen primary hematologic disorders have been associated with ischemic stroke. Inherited deficiencies of antithrombin III, protein C, and protein S have been linked with stroke in case reports; optimal screening requires functional as well as antigenic assays. Antiphospholipid antibodies and lupus anticoagulants are the most frequently identified acquired states associated with ischemic stroke. Polycythemia vera, sickle cell anemia, sickle-C disease, and essential thrombocythemia are the major disorders of formed blood elements causing stroke. Special, step-wise screening for occult prothrombotic entities in stroke patients is recommended for young persons with stroke of uncertain cause, for those with prior venous thrombosis, for those with a family history of unusual thrombosis, and for those with no other explanation for recurrent stroke. Acquired, perhaps transient, abnormalities of platelets, coagulation inhibition, and fibrinolysis may contribute importantly to brain ischemia in synergy with other mechanisms, but at present these remain ill-defined. The contribution of prothrombotic diatheses to stroke is probably underrecognized and warrants further investigation.

Autoimmune Diseases↗
PubMedDate not supplied

Interobserver variability in the ILAE classification of seizures in childhood.

Observer variability in interpreting medical tests and in making diagnoses influences both clinical practice and research. Uniform classification of epileptic seizures is especially difficult. Although the ILAE classification scheme for seizures has been available for many years, the reliability of this system has not been previously assessed. Verbatim descriptions of seizure manifestations were transcribed from medical records as part of a large, population-based prevalence study of childhood epilepsy conducted in two countries in central Oklahoma. One senior neurologist and three neurology residents reviewed these descriptions independently and classified them by seizure type based on the ILAE system. Unweighted and weighted kappa statistics were used to assess the level of agreement between the study neurologist and each resident. The overall agreement between observer pairs in classifying seizure types based on all available descriptions was relatively poor (kappa = 0.24-0.38). Some improvement was evident when unclassified seizures were excluded, and comparisons were restricted to those based on descriptions with some degree of detail (kappa = 0.34-0.51). When specific types of seizures were classified, agreement was fair to excellent for most types (kappa = 0.45-0.90), with the exceptions of atypical absence (kappa = 0.11-0.28), partial seizures with secondary generalization (kappa = 0.26-0.40), and generalized motor seizures (kappa = 0.29-0.32). Sources of observer variability in addition to the classification scheme are considered. Use of specific criteria for the categorization of symptoms might improve the reliability of seizure classification.

Adolescent↗