PubMed Health⌕ Search

Biomedical subjects

J M Valdueza

Publications and source records attributed to J M Valdueza.

At least 19 recordsLinked to original sources
PubMed2005

Multiple sclerosis coinciding with Machado-Joseph disease.

Although inflammatory demyelination is considered to be the key feature in multiple sclerosis (MS) pathogenesis, histopathological investigations and MRI studies recently highlighted the extent of neuronal damage that occurs even in the early stages of the disease. We report the unusual case of a patient with Machado-Joseph disease (MJD; spinocerebellar ataxia (SCA) III) and discuss this coincidence in light current pathogenetic paradigms of CNS autoimmunity.

Adult↗
PubMed2005

Internal jugular vein valve incompetence and intracranial venous anatomy in transient global amnesia.

BACKGROUND: Recently a causal relation between internal jugular vein valve incompetence (IJVVI) and transient global amnesia (TGA) has been suggested. IJVVI is postulated to provoke a transient mesiotemporal ischaemia by venous congestion. This mechanism requires a patent venous pathway from the affected IJV through the transverse sinus, confluens, straight sinus (SS), vein of Galen into the basal vein of Rosenthal and the internal cerebral veins. OBJECTIVE: To study IJVVI in TGA patients in relation to the intracranial venous anatomy. METHODS: IJVVI was defined if a repeated Valsalva manoeuvre (VM) led to a retrograde jugular flow detected by extracranial duplex ultrasound. Non-contrast venous MR angiography (MRA) was performed to analyse intracranial drainage patterns of the SS in relation to the side of the IJVVI. SS drainage was differentiated into three groups: predominantly right, left, and bilateral drainage. Ultrasound studies were performed in 25 TGA patients and 85 age matched controls. Twenty patients underwent venous MRA. RESULTS: Sixty eight per cent of patients and 33% of controls showed unilateral or bilateral IJVVI (p = 0.0025). In 36% of patients a TGA preceding VM was reported. Drainage pattern of SS and side of IJVVI corresponded in five of eight patients (63%) with VM and four of 12 patients without VM (33%, p = 0.0994). CONCLUSION: Our study confirms the significantly higher prevalence of IJVVI in TGA patients. However, no specific IJVVI related intracranial venous drainage patterns could be found to further support the hypothesis of a direct causal relation between IJVVI and TGA.

Adult↗
PubMed2004

A negative personal and family history for venous thrombotic events is not sufficient to exclude thrombophilia in patients with cerebral venous thrombosis.

A hereditary thrombophilia is found in 20-30% of patients with cerebral venous thrombosis (CVT). These patients might have an increased rate of a positive personal or family history of venous thrombotic events. We investigated the diagnostic value of a structured personal and family history for venous thrombotic events in 56 consecutive cases of CVT. Fourteen of 56 patients (25%) had a hereditary thrombophilia, mostly factor V Leiden. Patients with both CVT and hereditary thrombophilia had more frequently a positive family and personal history than patients affected by CVT only but the difference was not strong enough to differ from the 42 CVT patients without thrombophilia (43% vs. 31%; P = 0.52 and 14% vs. 10 %; P = 0.63). We conclude that a negative personal and family history of venous thrombotic events is not sufficient to exclude thrombophilia and patients with CVT should be tested for inherited thrombophilia regardless of the patient's past personal and family history for venous thrombotic events.

Adult↗
PubMed2003

Heparin treatment in cerebral sinus and venous thrombosis: patients at risk of fatal outcome.

We performed a retrospective analysis of 79 patients with cerebral sinus venous thrombosis, who were treated with a fixed regimen of dose-adjusted intravenous heparin, to determine predictors of a fatal course. The parameters investigated were the state of consciousness and the presence of intracranial haemorrhage (ICH) at the start of heparin treatment, involvement of the internal venous system, mean delay from initial symptom to stupor or coma and from initial symptom to hospital admission, focal neurological deficits, mean intracranial circulation time (ICT) on conventional angiography, and age and sex distribution. Mortality rate was 10% in this series (8/79). There was a strong link between the outcome and the level of vigilance: 53% of the patients with stupor or coma at the start of the heparin therapy died (8/15), whereas all of the 64 patients with no more than mildly impaired vigilance survived (p < 0.00001). Furthermore, mean age and mean ICT were significantly higher in the group of patients who died. There was a statistical trend (p = 0.056) for ICH to be more frequent in cases with fatal outcome, but there was reason to assume that ICH represented an epiphenomenon of a severe course rather than an independent predictor. Other investigated parameters were not linked with a fatal outcome.

Adolescent↗
PubMed2002

Transcranial ultrasonography of cerebral veins and sinuses.

Transcranial ultrasonography has become a valuable diagnostic tool for the bed-side evaluation of cerebral hemodynamics. While the assessment of arterial blood flow is well established, analysis of venous hemodynamics by transcranial ultrasonography is a new application of the method. The present review summarises the current state of transcranial venous ultrasound in adults by means of transcranial Doppler (TCD) and transcranial colour-coded duplex sonography (TCCS). It gives a critical overview regarding current and possible future clinical applications of the techniques.

Blood Flow Velocity↗
PubMed2002

Effects of prolonged head-down tilt on internal jugular vein cross-sectional area.

BACKGROUND: Head-down tilt is often used to assist cannulation of the internal jugular vein (IJV). However, the optimal duration of tilt before cannulation is not well defined. METHODS: Fifteen healthy volunteers were studied by B-mode duplex sonography to assess changes in cross-sectional area (CSA) of the right IJV during 10 degrees head-down tilt. RESULTS: Median CSA in the supine position was 102 mm(2) [range 16-266, mean (SD) 113 (69)]. CSA increased to 139 mm(2) [23-388, 158 (93)] immediately after tilting (P<0.0001, repeated measures ANOVA). No significant further change was noted in the next 20 min. CSA returned to baseline level after return to the supine position. CONCLUSION: The 10 degrees head-down tilt manoeuvre in healthy volunteers causes an immediate, significant increase in CSA in the right IJV. A longer tilt did not cause further increase in jugular CSA.

Adult↗
PubMed2001

Venous collateral blood flow assessed by Doppler ultrasound after unilateral radical neck dissection.

Removal of the internal jugular vein (IJV) in unilateral radical neck dissection (rND) necessitates redirection of cerebrovenous blood to collateral pathways. If adaptation is insufficient, neurologic sequelae develop that are due to impaired venous drainage and increased intracranial pressure. The authors studied venous hemodynamic effects of unilateral rND using Doppler and duplex ultrasound in 17 patients. Blood flow velocities (BFVs) were recorded from the distal IJV (dIJV) and the vertebral vein (VV) before and 9 to 88 days after surgery. A preoperative compression test of the dIJV was performed to identify the side of dominant drainage. The BFV increased in the contralateral dIJV after right-sided rND (n = 10) by 111% (range, 50% to 320%), and after left-sided rND (n = 7) by 34% (range, 5% to 105%). In the contralateral VV, a rise of BFV by 75% was found. Our results confirm the role of the contralateral dIJV as the predominant collateral pathway. The VVs serve as an important additional major outflow. Doppler ultrasound may help to identify patients at risk of insufficient cerebrovenous drainage after rND.

Blood Flow Velocity↗
PubMed2000

Postural dependency of the cerebral venous outflow.

We have shown that predominance of the jugular veins in cerebrovenous drainage is limited to the supine position. In the erect position, the vertebral venous system represents the major outflow pathway.

Adult↗
PubMed2000

Assessment of blood flow velocity and diameter of the middle cerebral artery during the acetazolamide provocation test by use of transcranial Doppler sonography and MR imaging.

BACKGROUND AND PURPOSE: Our purpose was to show changes in the diameter of the M1 segment of the middle cerebral artery (MCA) by using high-resolution MR imaging in patients with chronic internal carotid artery occlusion after IV administered acetazolamide challenge. Changes in blood flow velocity of the basal cerebral arteries are thought to correlate with changes of cerebral blood flow. Changes in the diameter of the basal cerebral arteries, however, might influence the validity of transcranial Doppler measurements. METHODS: Eight patients with internal carotid artery occlusion who were undergoing acetazolamide testing for assessment of cerebrovascular vasomotor reactivity were included in the study. Blood flow velocities of both MCAs were measured with transcranial Doppler sonography before and 25 minutes after the administration of acetazolamide. Before and 15 minutes after the administration of medication, MR imaging was performed contralateral to the occlusion side. A T2-weighted turbo-gradient spin-echo sequence was chosen to show a cross section of the M1 segment in high resolution (pixels, 0.27 x 0.29 mm). Based on interpolated data, the smallest and greatest MCA diameters were determined. RESULTS: We did not find changes in the diameter of the MCA after acetazolamide provocation testing with high-resolution MR imaging in patients with occlusive extracranial carotid artery disease. CONCLUSION: The results of our study support the hypothesis that changes in MCA flow velocity measured by transcranial Doppler sonography reflect relative changes in cerebral blood flow after acetazolamide provocation testing.

Acetazolamide↗
PubMed1999

Monitoring of venous hemodynamics in patients with cerebral venous thrombosis by transcranial Doppler ultrasound.

OBJECTIVES: To test the assumption that transcranial Doppler ultrasound (TCD) is able to detect and to monitor intracranial venous blood flow velocities in patients with confirmed cerebral venous thrombosis (CVT). DESIGN: Prospective case study in 18 patients. SETTING: Inpatient neurologic service in a university hospital. SUBJECTS AND METHODS: Serial TCD examinations were performed in 18 consecutive patients with CVT (14 females, 4 males) aged 16 to 64 years (mean+/-SD, 36.8+/-13.1 years) during a mean follow-up ranging from 34 to 783 days (mean+/-SD, 201+/-185 days) between 1993 and 1997. Venous TCD was performed with a 2-MHz range-gated transducer. RESULTS: Venous blood flow velocities were successfully measured in all patients. The highest measured velocities in the monitored intracranial venous vessels ranged from 20 to 150 cm/s (mean+/-SD, 58.9+/-38.8 cm/s), and the lowest were from 9 to 84 cm/s (mean+/-SD, 27.9+/-17.0 cm/s). Fifteen patients (83%) showed a decrease of velocities-2 of them after a transient increase during cessation of heparin therapy. The percentage of velocity decrease ranged from 34% to 73% (mean+/-SD, 56.4%+/-10.9%). A plateau phase, defined as no further decrease in velocities, was reached in these patients within 4 to 314 days (mean+/-SD, 59.9+/-73.7 days). Three patients (17%) showed no changes in velocities as defined by a limit of velocity variation of 30% during the course of CVT. High venous velocities were significantly associated with altered consciousness (P = .001). A nonsignificant relationship was observed with affliction of the superior sagittal sinus. No correlations were noted for onset of disease, initial motor deficits, and presence of bleeding. No predictive value was gained from analyzing the outcome in relation to absolute velocities or their decrease. CONCLUSIONS: Serial TCD studies allow monitoring of venous hemodynamics and collateral pathways in patients with CVT. Normal venous velocities in serial measurements, however, do not exclude a diagnosis of CVT.

Adolescent↗
PubMed1999

The inferior petrosal sinus: assessment by transcranial Doppler ultrasound using the suboccipital approach.

Recently, intracranial veins and sinuses have been successfully insonated using the transtemporal and transoccipital approaches by transcranial Doppler ultrasound. The purpose of this study was to prove the capacity of the Doppler method to evaluate the inferior petrosal sinus via the suboccipital approach. Venous transcranial ultrasound was performed with a range-gated 2-MHz transducer in 80 healthy volunteers and patients without central nervous system disorders ranging in age from 15-84 years (mean +/- standard deviation [SD], 37.6 +/- 15.2 years). A venous signal with a flow directed toward the probe was considered to originate from the inferior petrosal sinus because of its proximity to the basilar artery. The inferior petrosal sinus was insonated in 96.3% of the cases at least on one side. It was found bilaterally in 48 (60%), on the right side in 74 (92.5%), and on the left side in 51 (63.8%) subjects, respectively. Mean blood flow velocity ranged from 8-53 cm/s (mean +/- SD, 19.6 +/- 8.7 cm/s). A significant age dependency of venous velocities was found. Weak but significant side-to-side differences were observed, reflecting the known right-sided predominance of venous outflow in humans. Using the suboccipital approach, the inferior petrosal sinus can be insonated in a high percentage of subjects without major difficulties and is defined by its vicinity to the basilar artery.

Adolescent↗