Multiple sclerosis: a chronic infective cerebrospinal venulitis?

Pathogenesis and Management in Cerebrovenous Outflow Disorders

In keeping with its status as one of the major causes of disability and mortality worldwide, brain damage induced by cerebral arterial disease has been the subject of several decades of scientific investigation, which has resulted in a vastly improved understanding of its pathogenesis. Brain injury mediated by venous etiologies, however, such as cerebral, jugular, and vertebral venous outflow disturbance, have been largely ignored by clinicians. Unfortunately, this inattention is not proportional to the severity of cerebral venous diseases, as the impact they exact on the quality of life of affected patients may be no less than that of arterial diseases. This is evident in disease sequelae such as cerebral venous thrombosis (CVT)-mediated visual impairment, epilepsy, and intracranial hypertension; and the long-term unbearable head noise, tinnitus, headache, dizziness, sleeping disorder, and even severe intracranial hypertension induced by non-thrombotic cerebral venous sinus (CVS) stenosis and/or internal jugular venous (IJV) stenosis. In addition, the vertebral venous system (VVS), a large volume, valveless vascular network that stretches from the brain to the pelvis, provides a conduit for diffuse transmission of tumors, infections, or emboli, with potentially devastating clinical consequences. Moreover, the lack of specific features and focal neurologic signs seen with arterial etiologies render cerebral venous disease prone to both to misdiagnoses and missed diagnoses. It is therefore imperative that awareness be raised, and that as comprehensive an understanding as possible of these issues be cultivated. In this review, we attempt to facilitate these goals by systematically summarizing recent advances in the diagnosis and treatment of these entities, including CVT, CVS stenosis, and IJV stenosis, with the aim of providing a valid, practical reference for clinicians.

Neck vein obstruction: Diagnosis and the role of chronic persistent Chlamydophila pneumoniae infection

Background

The objective of this review is to describe the diagnosis of neck vein obstruction and the possible role of chronic persistent Chlamydophila pneumoniae infection in producing the syndrome of chronic cerebrospinal venous obstruction.

Method

The normal patterns of flow in the neck veins are described and guidelines for interpretation of the quantitative duplex ultrasound examination of the extracranial neck veins are developed.

Result

An infective cause of neck vein obstruction is proposed and from a literature search of the role of the obligate intracellular bacterium Chlamydophila pneumoniae in vascular and chronic diseases, a diagnostic protocol for confirming chronic persistent Chlamydophila pneumoniae infection, which includes the quantitative duplex ultrasound examination and specific blood tests are suggested.

Conclusion

Further research to validate this diagnostic protocol is required.

Centralized and Local Color Doppler Ultrasound Reading Agreement for Diagnosis of the Chronic Cerebrospinal Venous Insufficiency in Patients with Multiple Sclerosis

Background:

An impaired cerebrospinal venous drainage was postulated to be a cofactor in the multifactorial path-ogenesis of multiple sclerosis (MS). Chronic cerebrospinal venous insufficiency (CCSVI) is characterized by abnormalities of the main extracranial cerebrospinal venous outflow routes, which can be detected by color Doppler Ultrasound (CDUS) using 5 venous hemodynamic (VH) criteria. Discrepant results between different investigators were reported in the past, therefore the usefulness and applicability of the CCSVI CDUS-based diagnosis in clinical research and practice has been questioned.

The reproducibility of proposed criteria for CCSVI detection depends on the blinding, training level, skills of the operator and interpretation of VH criteria.

Objectives:

To assess agreement between centralized and local reading of CDUS examination for diagnosis of CCSVI in trained Doppler sonologists.

Methods:

This study was performed in 78 MS patients and 28 age- and sex-matched healthy controls (HCs). Extracranial and transcranial CDUS venous hemodynamic assessment was conducted, according to International Society of Neurovascu-lar Disease (ISNVD) recommended criteria, by a single CCSVI-trained expert sonologist blinded to the subject disease sta-tus. After the local Doppler sonologist performed the investigation, all images and video clips of the CDUS examination were sent to the centralized reading center, where a second blinded reading was performed by two CCSVI-trained expert sonologists. Statistical analyses were performed comparing accuracy of CCSVI diagnosis (≥2 VH criteria) and each of the 5 individual VH criteria using Cohen kappa statistic, along with positive/negative agreement and Odds ratio (OR) with 95% confidence intervals (95% CI).

Results:

Diagnosis of CCSVI was obtained in 59.7% of local and 64.3% centralized readers (Kappa, 0.67, p<0.001). Simi-lar Kappa values were obtained for CCSVI diagnosis and individual CCSVI criteria in both MS patients and HCs. The high-est Kappa between local and centralized readers was observed for VH criteria 5 (0.93) followed by VH criteria 4 (0.70), VH criteria 1 (0.66), VH criteria 2 (0.64) and VH criteria 3 (0.58). The positive predictive value (PPV) and negative predictive value (NPV) for CCSVI diagnosis were 82.7% and 86,7%, respectively with an OR of 31.1 (95% CI 11.1-87.5, p<0.001). The highest agreement between local and centralized readers was observed for VH criteria 4 (OR 98.7, 95% CI 17.1-569.9, p<0.001) with 72.7% PPV and 97.3% NPV followed by VH criteria 5 (53, 95% CI 13.4-209.2, p<0.001) with 98.1% PPV and 100% NPV value.

Conclusion:

Centralized reading of the CDUS examination for the diagnosis of CCSVI is feasible with high accuracy in CCSVI-trained Doppler sonologists. The most reproducible VH criteria between local and centralized readers were VH cri-teria 4 and 5.

A prolonged antibiotic protocol to treat persistent Chlamydophila pneumoniae infection improves the extracranial venous circulation in multiple sclerosis

Objective Chronic cerebrospinal venous insufficiency (CCSVI) is a condition associated with multiple sclerosis (MS). One mechanism that has been proposed is that the venous obstructions found in MS are due to a chronic persistent venulitis caused by the intra-cellular bacterial parasite, Chlamydophila pneumoniae (Cpn). The objective of the current study is to determine the effect of a combined antibiotic protocol (CAP) on the venous flow in MS patients as measured by a quantitative duplex ultrasound examination (QDUS). Method A non-randomised before-after cohort study was conducted to investigate differences in blood flow volumes pre and 6-months post antibiotic treatment for Cpn infection. Flow volume data were measured by QDUS across affected and unaffected sides from multiple veins segments, including internal jugular vein (IJV) segments J2 and J3, and vertebral vein (VV), as well as global arterial blood flow (GABF). Results 91 patients were included in the study. 64 (70%) were found to have positive Cpn serology. There was a statistically significant post-treatment difference seen for the affected side of Cpn infected patients (mean difference = 56 mL/min, p = 0.02). There was a non-significant increase seen for the affected side of uninfected patients (mean difference = 23 mL/min, p = 0.2). The difference in these effects (34 mL/min) was not statistically significant ( p = 0.3). The mean flow rate decreased in the unaffected side for both infected (-27 mL/min, p = 0.5) and uninfected patients (-69 mL/min, p = 0.01). There was a statistically significant post-treatment increase in GABF for the infected patients (mean difference = 90 mL/min, p = 0.02) and a difference of 76 mL/min for non-infected patients ( p = 0.01). Conclusion A CAP appears to improve the extra-cranial circulation in patients diagnosed with MS. This effect is statistically significant in patients with positive Cpn serology, although patients with negative Cpn serology also show some benefit, betraying a lack of specificity of this effect.

Transcranial brain photoplethysmography to study the venules of cerebral cortex in patients with multiple sclerosis

Objective

To evaluate the utility of a transcranial brain photoplethysmography parameter as a potential marker for patients with multiple sclerosis.

Methods

We investigated 38 patients affected by multiple sclerosis, according to the revised McDonald criteria (12 males and 26 females, mean age 41.1 ± 8.5 years, Expanded Disability Status Scale mean value 2.6 ± 2.1) and compared them with 20 age- and sex-matched healthy controls. By means of transcranial brain photoplethysmography, a safe and non-invasive technology, we measured the increase in cerebral blood volume during compression for 10 s of the internal jugular veins of both sides in sitting position.

Results

The cerebral blood volume increase was significantly smaller in the multiple sclerosis patients (left frontal cortex: −58%, p < 0.0001; right frontal cortex: −59%, p < 0.0001) compared with the controls.

Conclusions

Our study reveals that a minor increase in cerebral blood volume on the frontal cortex of both sides in sitting position is associated with a diagnosis of multiple sclerosis and might be a new marker.

Potential involvement of the extracranial venous system in central nervous system disorders and aging

BACKGROUND

The role of the extracranial venous system in the pathology of central nervous system (CNS) disorders and aging is largely unknown. It is acknowledged that the development of the venous system is subject to many variations and that these variations do not necessarily represent pathological findings. The idea has been changing with regards to the extracranial venous system.

DISCUSSION

A range of extracranial venous abnormalities have recently been reported, which could be classified as structural/morphological, hemodynamic/functional and those determined only by the composite criteria and use of multimodal imaging. The presence of these abnormalities usually disrupts normal blood flow and is associated with the development of prominent collateral circulation. The etiology of these abnormalities may be related to embryologic developmental arrest, aging or other comorbidities. Several CNS disorders have been linked to the presence and severity of jugular venous reflux. Another composite criteria-based vascular condition named chronic cerebrospinal venous insufficiency (CCSVI) was recently introduced. CCSVI is characterized by abnormalities of the main extracranial cerebrospinal venous outflow routes that may interfere with normal venous outflow.

SUMMARY

Additional research is needed to better define the role of the extracranial venous system in relation to CNS disorders and aging. The use of endovascular treatment for the correction of these extracranial venous abnormalities should be discouraged, until potential benefit is demonstrated in properly-designed, blinded, randomized and controlled clinical trials.

Chronic cerebrospinal venous insufficiency is unlikely to be a direct trigger of multiple sclerosis

BACKGROUND

Chronic cerebrospinal venous insufficiency, a vascular pathology affecting the veins draining the central nervous system can accompany multiple sclerosis and is suspected to be involved in its pathogenesis.

OBJECTIVE

This study was aimed at exploring a potential role for chronic cerebrospinal venous insufficiency in triggering multiple sclerosis. If it were venous abnormalities responsible for neurological pathology, one should expect negative correlation, i.e. more severe vascular lesions in the patients with early onset of multiple sclerosis.

METHODS

Localization and degree of venous blockages in 350 multiple sclerosis patients were assessed using catheter venography. Statistical analysis comprised evaluation of the correlations between severity of venous lesions and patients' age at onset of the disease.

RESULTS

We found weak, yet statistically significant positive correlations between patients' age at onset of multiple sclerosis and accumulated and maximal scores of venous lesions. The patients, also those with duration of multiple sclerosis not longer than 5 years, who had their first attack of the disease at younger age, presented with less severe vascular lesions.

CONCLUSION

Positive correlation suggests that venous lesions are not directly triggering multiple sclerosis. There should be another factor that initiates pathological processes in the central nervous system.

The role of noninvasive and invasive diagnostic imaging techniques for detection of extra-cranial venous system anomalies and developmental variants

The extra-cranial venous system is complex and not well studied in comparison to the peripheral venous system. A newly proposed vascular condition, named chronic cerebrospinal venous insufficiency (CCSVI), described initially in patients with multiple sclerosis (MS) has triggered intense interest in better understanding of the role of extra-cranial venous anomalies and developmental variants. So far, there is no established diagnostic imaging modality, non-invasive or invasive, that can serve as the "gold standard" for detection of these venous anomalies. However, consensus guidelines and standardized imaging protocols are emerging. Most likely, a multimodal imaging approach will ultimately be the most comprehensive means for screening, diagnostic and monitoring purposes. Further research is needed to determine the spectrum of extra-cranial venous pathology and to compare the imaging findings with pathological examinations. The ability to define and reliably detect noninvasively these anomalies is an essential step toward establishing their incidence and prevalence. The role for these anomalies in causing significant hemodynamic consequences for the intra-cranial venous drainage in MS patients and other neurologic disorders, and in aging, remains unproven.

Chronic cerebrospinal venous insufficiency is not more prevalent in patients with mild multiple sclerosis: a sonographer-blinded, case-control ultrasound study

OBJECTIVES

We designed a prospective case-control study of patients with clinically isolated syndrome (CIS) and Relapsing-Remitting Multiple Sclerosis (RRMS) with an Expanded Disability Status Score (EDSS) of ≤2, compared with age-and-sex-matched healthy controls, to test the hypothesis that chronic cerebrospinal venous insufficiency (CCSVI) is more prevalent in patients with CIS or mild MS.

METHODS

All subjects were examined using a Siemens Antares duplex ultrasound machine. The internal jugular, vertebral and intracranial veins were studied in subjects in both supine and sitting postures. The sonographer was blind to the subject's clinical status. Measures included the criteria proposed by Zamboni and volume flow. Presence of CCSVI was defined as ≥2 Zamboni criteria.

RESULTS

Seventy patient-control pairs were recruited, with 11 males and 59 females in each group. Only one subject, a control, satisfied the Zamboni definition of CCSVI; however, 19 patients and 13 controls had abnormalities as defined by Zamboni, the difference largely caused by a higher prevalence in patients of internal jugular vein (IJV) stenosis, defined as a cross-sectional area ≤0.3cm(2). This difference disappeared with a more rigorous stenosis definition. Further analysis revealed there was IJV valve variation in seven patients and one control.

CONCLUSIONS

Our findings indicate that CCSVI, as defined by the Zamboni ultrasound criteria, is not present in CIS and mild RRMS (EDSS ≤2), providing further evidence that CCSVI does not have a causal role in MS; however, we found an apparent increase in IJV variation in patients with CIS or mild MS that would warrant further investigation.