Biomedical subjects
Publications and source records attributed to M Sturzenegger.
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Vertebrobasilar insufficiency is a very imprecise and much too frequently applied diagnostic term, usually used to classify uncharacteristic intermittent symptoms such as dizziness or visual blurring. Detailed history may make it possible to identify more specific details. Diagnostic attempts nowadays should aim at identifying underlying pathophysiologic mechanisms: intrinsic vessel disease (e.g. atherosclerosis), extrinsic vessel compression (e.g. cervical spondylarthrosis), systemic affections (e.g. anemia, hypotension), or combined etiologies. Accordingly, various therapeutic options exist. Ultrasound examination of the vertebrobasilar system is a reliable screening method in skilled hands, though its sensitivity is lower than in carotid artery disease. To identify the site and nature of the underlying pathology, digital angiography and, probably soon, magnetic resonance angiography (MRA) are available.
We report a young woman presenting with "painful diplopia" caused by inflammation of external eye muscles affecting both eyes sequentially. Orbital MRI disclosed swelling, signal hyperintensity and enhancement of isolated eye muscles. Corticosteroid treatment led to a complete remission within a few days. The compiled data of a literature review enclosing 52 sufficiently documented patients diagnosed as orbital myositis is reported with respect to clinical features, laboratory findings, associated disease, value of imaging procedures (CT,MRI). Therapeutic aspects and differential diagnosis are reviewed.
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OBJECTIVES: Dural puncture is regarded a safe procedure when contraindications are carefully excluded and has so far not been recognised as a risk factor for cerebral venous sinus thrombosis (CVST). Five patients are described with CVST after dural puncture in the presence of additional risk factors. METHODS: In four out of five patients complete investigations for thrombophilia were performed at least one month after withdrawal of oral anticoagulation. RESULTS: In three out of four patients tested, activated protein C (APC) resistance due to heterozygous coagulation factor V R506Q mutation (factor V Leiden) was found. One patient was using oral contraceptives as a circumstantial risk factor and three had had spinal anaesthesia for surgical procedures. Family history of venous thromboembolism was negative in all patients. Retrospective evaluation of 66 patients with CVST disclosed that dural puncture was the fourth most common risk factor (8%) possibly contributing to thrombosis. CONCLUSION: Dural puncture may constitute an additional risk factor for CVST especially in patients with APC resistance or surgery. In such patients a thrombophilia screen is indicated.
BACKGROUND AND PURPOSE: Intraoperative monitoring of brain function may influence the outcome of carotid endarterectomy (CEA). METHODS: We performed transcranial Doppler (TCD) monitoring of middle cerebral artery blood flow velocities (VMCAs) and eight-channel electroencephalographic (EEG) recording simultaneously in 82 patients undergoing CEA. Thiopental narcosis limited EEG interpretation in 11 patients, thus allowing direct comparison of both methods in 71 patients. RESULTS: There was a significant correlation between VMCA decrease and the frequency of EEG changes after carotid clamping (P < .001). Eight patients (11%) showed a VMCA decrease exceeding 60%, accompanied by EEG changes in 7 patients. Altogether, 16 patients (22%) showed severe or moderate EEG changes. Stenosis or occlusion of the contralateral carotid artery led to an increase of abnormal findings with both monitoring methods, which was, however, significant only for TCD (P < .05). Four patients (4.8%) suffered intraoperative transient ischemic attacks. In 3 of these patients, there were no abnormal findings with either of the methods. The events were thus unpredictable and probably of embolic origin. The fourth patient showed VMCA decrease to 0 and severe EEG changes. Nine patients had severe or moderate EEG changes without significant VMCA decrease and without complications. EEG monitoring alone in these would have led to unnecessary use of a shunt with the increased risk of embolism. CONCLUSION: EEG and TCD monitoring are complementary techniques. Their results showed a good overall correlation but with marked differences in the individual patient. TCD monitoring alone was sensitive enough to prevent ischemic intraoperative complications. EEG findings are of limited value when barbiturates are used.
Hypertension is one of the most important cardiovascular risk factors. Without therapy hypertension leads to stroke, coronary heart disease with angina pectoris and myocardial infarction, kidney failure and/or peripheral vascular disease. The association between blood pressure and these cardiovascular complications can be demonstrated over the entire blood pressure range. The risk of stroke, myocardial infarction, renal failure or peripheral vascular disease increases with increasing blood pressure. Additional cardiovascular risk factors such as hyperlipidemia, smoking and diabetes involve a further increase in risk. Today hypertension can be effectively treated. To that end, diuretics, betablockers, ACE-inhibitors or calcium antagonists can be used. Alpha receptor antagonists and angiotensin AT1 receptor antagonists are also of value. The antihypertensive effectiveness of these drugs is comparable but may vary in individual patients. During antihypertensive therapy, a reduction in cerebrovascular and cardiac complications has been demonstrated for alpha methyldopa, diuretics and betablockers. In these studies, fatal and non-fatal strokes were reduced by 42%, while the reduction in cardiac events was less pronounced (14%). The reasons for this greater efficacy of antihypertensive therapy in the cerebral circulation are not clear. Other risk factors may be particularly important in the pathogenesis of coronary artery disease (e.g. genetic factors, hyperlipidemia and others) or hypertensive vascular changes in the coronary circulation may not be as reversible as they are in the cerebral circulation. The well documented correlation between stroke, myocardial infarction and hypertension, as well as the proven efficacy of antihypertensive therapy in preventing cardiovascular events, underscores the importance of effective and sustained blood pressure control in these patients.
We report the diagnostic evaluation of an elderly woman admitted with recurrent syncopes induced by head rotation. A cardiac origin was exclude by Holter ECG, echocardiography and carotid sinus compression. Angiography showed unilateral vertebral artery hypoplasia, suggesting the possibility of hemodynamic vertebrobasilar insufficiency. This origin, however, could be ruled out by monitoring of blood flow velocities in both posterior cerebral arteries with transcranial Doppler, which showed no alteration during syncope induced by head rotation. Detailed analysis of the course of the syncope recorded on videotape suggested a psychogenic event. Furthermore, the syncopes could be prevented with a "protective" placebo despite head rotation, and induced by a "provocative" placebo without head rotation while EEG monitoring showed normal brain activity. This finding underscored the suggestion of a psychogenic cause.
Six patients with Hashimoto thyroiditis (HT) and associated encephalopathy (HE) are described and compared with 14 well-documented cases retrieved from the literature. HE typically affects patients when they are euthyroid and, in an appropriate clinical situation, antithyroid autoantibodies are the main indicators of HE. Since clinical features of HE are unspecific, other aetiologies such as infectious, metabolic, toxic, vascular, neoplastic, and paraneoplastic causes have to be excluded. Our own six cases and those from the literature show that two types of initial clinical presentation can be differentiated: a vasculitic type with stroke-like episodes and mild cognitive impairment in nine patients, and a diffuse progressive type with dementia, seizures, psychotic episodes or altered consciousness in 11 patients. These types may overlap, particularly in the long-term course without treatment. Response to steroids was usually excellent with complete remission in 80%. Eighteen of the 20 patients were women. Characteristic, though unspecific, findings were abnormal EEG (90%) and CSF (80%). Together with quantitative neuropsychological testing, these proved sensitive for monitoring the efficacy of therapy. Conversely, antithyroid autoantibody titres did not correlate with the severity or type of clinical presentation. The link between HE and HT is not clear. A pathogenetic role for antithyroid autoantibodies in the central nervous system seems unlikely.
PURPOSE: To analyze the usefulness of magnetic resonance (MR) imaging techniques and diagnostic sensitivity in internal and carotid artery dissection (ICAD) and to correlate these findings with those of other imaging modalities and with clinical signs. MATERIALS AND METHODS: Thirty-one patients with ICAD underwent MR imaging within 2-40 days (mean, 13 days) after onset of clinical symptoms. All patients initially underwent Doppler sonography; 15 patients underwent additional angiographic studies. RESULTS: T1-weighted fat-suppressed MR images most accurately demonstrated intramural hematoma in the internal carotid artery (ICA) in all patients. Kinking or coiling of the ICA was found in nine (29%) patients. Hyperintense signal was seen on T1- and T2-weighted images in the carotid canal or in the cavernous sinus in two-thirds of the patients. Findings characteristic of ICAD were seen on 13 of 16 angiograms. CONCLUSION: MR imaging most accurately demonstrated ICAD. The high rate of kinking and coiling in the carotid artery suggests that these anatomic conditions may be predisposing factors.
The present study aimed to establish criteria for delayed recovery after whiplash injury using a 1-year prospective cohort study. 117 whiplash patients referred from primary care and 16 whiplash patients recruited from the insurance company. At baseline all patients underwent neurological, radiological and psychosocial factors assessment and testing of personality traits, well-being, cognitive ability and cognitive functioning. According to the logistic regression in patients referred from primary care the following initial variables are in significant relationship with poor outcome at 1 year: impaired neck movement, history of pretraumatic headache, history of head trauma, higher age, initial neck pain intensity, initial headache intensity, nervousness score, neuroticism score and test score on focused attention. Employing these variables, correct prediction of outcome at 1 year was found in 88% of patients recruited from the insurance company. Authors conclude that a comprehensive assessment of whiplash patients early after trauma enables physicians to identify patients at risk of delayed recovery.
A 60-year-old patient presenting with the typical features of progressive sensory neuronopathy and subsequent intestinal pseudo-obstruction was found to have antineuronal nuclear antibodies (ANNA-I or Anti-Hu). These findings were suggestive of a paraneoplastic syndrome, but neither clinically nor at autopsy could a neoplasm be detected. Neuropathological findings were identical with those known for carcinoma-associated forms with marked neuron loss of spinal sensory ganglia and myenteric plexus. Therefore, ANNA-I and intestinal pseudo-obstruction may in rare cases occur without detectable underlying cancer.
BACKGROUND AND PURPOSE: Spontaneous cervical artery dissection (SCAD) is a common cause of stroke in the young; however, its recurrence has been rarely studied. Recurrent SCAD at the level of the previously dissected vessel has been reported in only six patients. METHODS: We prospectively evaluated and followed a series of 81 patients seen in our center with carotid (n = 66) or vertebral (n = 15) artery dissection, in whom the diagnosis was confirmed by angiography, MRI, or both. Repeated clinical and ultrasound examinations were performed in all patients during a mean follow-up of 34 months (range, 12 to 57 months). RESULTS: Three patients died of the consequences of stroke, and four patients were unavailable for follow-up. Three of the remaining 74 patients (4%) had a recurrent carotid dissection while under prophylaxis with aspirin (n = 2) or anticoagulation (n = 1). None of the patients had a recurrent vertebral dissection. Recurrent carotid dissection occurred 16 months to 4 years after the first episode and presented with acute head and neck pain (n = 2) and hemispheric transient ischemic attack (n = 1). In one patient recurrence was documented by Doppler and MRI at the level of the first dissection. CONCLUSIONS: We confirm that recurrence of SCAD is uncommon and usually represents a benign condition. Delayed recurrence seems to be more common than previously suggested and can occur at the level of the previously dissected vessel.
BACKGROUND AND PURPOSE: We assessed the influence of different visual stimuli and the reproducibility and habituation of evoked flow responses using simultaneous two-channel transcranial Doppler monitoring and flow velocity averaging. METHODS: We measured stimulus-related percentage changes in posterior cerebral, basilar, and middle cerebral artery blood flow velocities in 14 normal volunteers using stimulus-triggered velocity averaging. With a two-channel transcranial Doppler system, simultaneous measurements in two arteries (both posterior cerebral arteries and the basilar and middle cerebral artery) were taken using multiple-array light-emitting diodes applying flash stimuli. Both posterior cerebral arteries were monitored to assess reproducibility and habituation of the evoked response with repetitive measurements under unchanged conditions and to analyze the influence of different features of the visual stimulus. RESULTS: There was a distinctive increase in velocities resulting from visual stimuli in both posterior cerebral and the basilar arteries but not in the middle cerebral artery. The responses in both posterior cerebral arteries were larger than in the basilar artery (P = .0001). Brightness (P < .0001), as well as complexity (P < .0001), of the visual stimulus had a significant influence on the response amplitude. There was a trend toward a greater right-sided activation. Amplitudes of the evoked response were very stable during repetitive testing (coefficient of variation of the difference was 0.6). There was a trend toward habituation with monotonous (flash) but not with complex visual stimuli. A "zero" stimulus produced no responses. CONCLUSIONS: The use of flow velocity averaging and two-channel simultaneous recording increases the sensitivity of transcranial Doppler monitoring to detect and correlate selective flow changes in the posterior cerebral arteries resulting from cerebral activation produced by visual stimulation.
BACKGROUND AND PURPOSE: A subject with dissection of the internal carotid artery (ICA) may present with a variety of symptoms, from headache to stroke. Thus far, it has not been possible to identify the subset of patients at risk for cerebral ischemia. Because the majority of these ischemic events are secondary to embolic phenomena, we used transcranial Doppler (TCD) evaluation with emboli monitoring to study 17 consecutive patients with ICA dissection treated at Harborview Medical Center, Seattle, Wash, during a 2-year period from 1992 until 1994. METHODS: Ten patients with ICA dissection secondary to trauma and seven with spontaneous ICA dissection were diagnosed by carotid angiography and studied by TCD from the time of diagnosis through initiation of therapy. Emboli monitoring was performed in the middle cerebral artery (MCA) ipsilateral to the dissection at the initial evaluation and intermittently thereafter to ensure that the emboli stopped with treatment. RESULTS: Emboli were detected in the MCA distal to the dissection in 10 of 17 patients (59%). Patients with microemboli detected by TCD presented with a stroke (70%) much more frequently than those without emboli (14%) (P=.0498). The presence of a pseudoaneurysm did not increase the risk of either microemboli or stroke. CONCLUSIONS: We have demonstrated a high incidence of intracranial microemboli in the MCA distal to carotid dissections and a significant correlation between the presence of emboli and stroke. TCD can therefore be used as an adjunctive tool to manage patients with suspected carotid dissection and may prove useful in evaluating the efficacy of treatment in reducing microemboli and subsequent stroke.
The main symptom of arterial dissection is intense acute unilateral headache. The pain is commonly located around the eye, in the temple or the front with a carotid artery dissection [CAD] and in the posterior neck and occiput with a vertebral artery dissection [VAD]. Transient or persistent cerebral ischemic symptoms are similarly frequent but usually occur later in the time course. Horner's syndrome indicating a lesion of perivascular sympathetic fibres represents the third leading symptom and occurs in more than one third of the patients. Compression of local structures such as lower nerve or radicular palsies is rare. This constellation of symptoms in a young patient without vascular risk factors should rise suspicion of a dissection, in particular, if there is a preceding 'trivial' trauma. Characteristic features on Doppler/duplex sonography provide the diagnosis of dissection in almost all CAD and the majority of VAD. MRI demonstrating the mural hematoma allows reliable confirmation of the suspected diagnosis. Angiography is necessary only in selected cases, more often in VAD than in CAD. Brain infarction may be prevented, if premonitory symptoms, which occur in 60 to 80% of the patients, are recognized as such. Therefore, if there is clinical and sonographic suspicion of CAD or VAD, anticoagulation therapy with heparin should should be started before other imaging procedures finally prove the diagnosis. Because immediate anticoagulation may prevent cerebral embolism, this treatment strategy seems appropriate, although its efficacy has not been established by a controlled study. Anticoagulation should be continued until resolution of the dissection.