Carotid artery dissections: thrombosis of the false lumen

Carotid artery dissections are the second leading cause of stroke in young adults. The hemostatic response to a dissection involves exposure of the subendothelium to the intravascular environment. Platelet activation/aggregation superimposed by secondary coagulation cascade activity attempts to heal the injury. Failure of the hemostatic response to heal the injury may lead to further rupture of the intimal and medial layers, which allows for the blood to penetrate these layers to create a false lumen. Continued hemorrhaging into the false lumen may result in dissection progression or obstruction of blood supply to the true lumen and downstream blood vessels. The effects of thrombosis in the true versus false lumen may lead to opposite consequences. True lumen clotting may lead to ischemic complications of downstream cerebral vasculature, whereas false lumen clotting may lead to dissection healing. Current information on clinical outcomes and degree of false lumen clotting in a carotid dissection model is limited, and most of the available information on this controversial topic has been inferred from aortic dissections. Therefore in this report we summarize the present state of knowledge of the pathophysiology, detailed hemostatic response to the injury, clinical presentation and treatment of carotid dissections. We also emphasize the need for future studies to investigate the degree of false lumen clotting on the clinical outcomes of carotid dissections.     

Cryptococcosis in AIDS patients: observations concerning CNS involvement

Summary The clinical course and response to therapy of seven patients with cryptococcosis and AIDS were reviewed. One patient was still in the primary stage of cryptococcosis in AIDS, i.e. the stage that is characterized by the sole cultural detection of Cryptococcus neoformans in the respiratory tract. The other six patients were in the secondary stage, where C. neoformans can be detected from the cerebrospinal fluid (CSF), blood, urine, faeces and other body sites. The main presenting features (headache, fever, nausea) were due to central nervous system involvement, although meningism and mental changes were rarely present, and CSF changes were very subtle. Treatment with amphotericin B and flucytosine was very effective, there being no more growth of fungi in cultures in most cases. Adverse reactions to the drugs used occurred frequently and consisted mainly of anaemia, hepatosis and fever. Diagnosis in the primary stage of cryptococcosis may improve the prognosis.     

Extracranial vertebral artery dissections: a review of 13 cases

Clinical and radiologic findings in 13 patients (11 women, 2 men) with extracranial vertebral artery dissection are reported. Dissection was spontaneous in 8 patients, occurred after neck manipulation in 2 and after a potential minor injury to the neck in 3. Six had a history of common migraine, 4 were using oral contraceptives at the time of dissection, and 3 had fibromuscular dysplasia. Dissection was bilateral in 8 patients and associated with carotid dissection in 3. It usually presented with neck or occipital pain preceding basilar ischemic symptoms by a few minutes to 1 month. In 3 patients, transient ischemic attacks were the only manifestation of basilar ischemia, and in 1 patient there was no symptom of basilar ischemia despite bilateral vertebral dissection. In 19 of the 21 dissected vertebral arteries, the angiographic appearance was that of an irregular stenosis, which was associated in 6 arteries with pseudoaneurysmal formation. In 2 patients, 1 vertebral artery was occluded but the contralateral artery showed the typical irregular stenosis. The dissection involved only the third segment in 33%, only the second segment in 24%, and 2 or more segments in 38%. Eleven patients were treated with anticoagulants and 2 with aspirin; 11 recovered without sequelae and 2 had residual deficit. No recurrence was observed (mean follow-up 34 months). At control angiography (n = 12) or ultrasonic study (n = 1), 63% of dissected vertebral arteries had returned to normal, 26% showed marked improvement, and 11% were occluded. Our patient characteristics are compared with those of previously published cases. The validity of the distinction between spontaneous dissection and dissection associated with minor trauma is discussed.     

Cerebral blood flow changes in migraine: methods, observations and hypotheses

A number of basically different methods have been used in studies of the cerebrovascular changes which occur in migraine and each individual set of findings seems to be dependent on which method is used. One method on its own can only disclose a part of all the pathophysiological events. This review is an attempt to consider the capabilities of each method and to bring together the results from different studies on migraine in order to create a complete picture of the cerebrovascular changes which occur during the course of a migraine attack.     

Pathogenesis of cervical artery dissections: association with connective tissue abnormalities.

BACKGROUND: The etiology of spontaneous cervical artery dissection (CAD) is largely unknown. An underlying connective tissue disorder has often been postulated. OBJECTIVE: To further assess the association of CAD with ultrastructural abnormalities of the dermal connective tissue. METHODS: In a multicenter study, skin biopsies of 65 patients with proven nontraumatic CAD and 10 control subjects were evaluated. The ultrastructural morphology of the dermal connective tissue components was assessed by transmission electron microscopy. RESULTS: Only three patients (5%) had clinical manifestations of skin, joint, or skeletal abnormalities. Ultrastructural aberrations were seen in 36 of 65 patients (55%), consisting of the regular occurrence of composite fibrils within collagen bundles that in some cases resembled the aberrations found in Ehlers-Danlos syndrome type II or III and elastic fiber abnormalities with minicalcifications and fragmentation. A grading scale according to the severity of the findings is introduced. Intraindividual variability over time was excluded by a second biopsy of the skin in eight patients with pronounced aberrations. Recurrent CAD correlated with connective tissue aberrations. In addition, similar connective tissue abnormalities were detected in four first-degree relatives with familial CAD. CONCLUSION: CAD is associated with ultrastructural connective tissue abnormalities, mostly without other clinical manifestations of a connective tissue disease. A structural defect in the extracellular matrix of the arterial wall leading to a genetic predisposition is suggested. The dermal connective tissue abnormalities detected can serve as a phenotypic marker for further genetic studies in patients with CAD and large families to possibly identify the underlying basic molecular defect(s).     

Neuroimaging and neurophysiology of periodic lateralized epileptiform discharges: observations and hypotheses

PURPOSE: We assessed neuroimaging lesion type and distribution in patients with periodic lateralized epileptiform discharges (PLEDs), with a view to identifying electrographic differences between PLEDs associated with differing lesion locations. Our observations led us to consider a conceptual synthesis between PLEDs and periodic complexes (PCs). METHODS: Retrospective review of acute neuroimaging results (CT/MRI) on patients identified to have EEG PLEDs, for the period 1999-2003 (n=106). Blinded classification of original EEG recordings. RESULTS: Neuroimaging abnormalities were classified as acute or chronic cortical, or acute or chronic subcortical. Seven out of 106 scans were classified nonlesional. Overall approximately 70% of scans had cortical abnormalities, whether acute or chronic; approximately 23% had subcortical abnormalities. "Cortical" PLEDs were significantly longer in duration (p<0.05) and more variable in morphology (p<0.01) than "subcortical" PLEDs. CONCLUSIONS: Structural brain disease commonly, but not invariably, underlies PLEDs; lesion type is spatiotemporally variable. Cortical and subcortical PLEDs have distinct EEG signatures. There is evidence that these may relate to mechanisms for other pathological large-scale oscillatory brain synchronies (e.g., PCs).     

Pediatric traumatic carotid, vertebral and cerebral artery dissections: a review

Traumatic cerebral dissections are rare but potentially dangerous conditions that through improved diagnostics have recently gained increased interest. However, there is still a significant lack of knowledge on the natural history, as well as on the best treatment options. Most of the literature on this topic consists of case reports and retrospective studies with no prospective randomized controlled studies. In our review, we highlight the fact that there is no level 1 evidence for the natural history of cerebral dissections or for the best treatment. We present 26 case studies derived from 70 pediatric patients affected by dissections, occlusions, and pseudoaneurysms.