Cerebri Syndrome

The study of Janny et al. [71] was a landmark in the study of PTS. The authors studied 16 patients with primary PTS using a combination of ventricular CSF pressure monitoring, SSS pressure monitoring and direct antegrade venography via a midline frontal burr-hole. They demonstrated venous sinus obstruction in 5 of 16 patients. In 4 of these patients the obstruction was at the level of the transverse sinus, being bilateral, or single in a functionally predominant sinus. Although issues of lesion morphology or aetiology were not addressed it suggested that the prevalence of venous sinus obstruction in primary PTS may be higher than previously appreciated.

Unfortunately, the issues raised by Janny et al. received little attention in the literature with only sporadic reports on the topic of PTS and venous sinus pathology. One example is that of Bortoluzzi et al. [17] who reported a case of PTS with severe radiculopathy in whom obstruction of a dominant right transverse sinus was clearly demonstrated with venography. Cremer et al. [27] also reported a single case of bilateral transverse/sigmoid sinus stenosis with pressure gradients on manometry, probably due to giant arachnoid granulations, in a patient with PTS.

In the mid-1990's two important papers detailed the findings of direct retrograde cerebral venography (DRCV) with manometry in the study of PTS patients. The first was that of King et al. [86] who studied 11 patients. All had undergone CT, static MRI and conventional angiography. One patient was suspected of harbouring a SSS thrombosis on MRI but this was not confirmed on other investigations. Venous manometry demonstrated elevated SSS pressures in 9 patients; the remaining 2 patients were those in whom minocycline had been implicated in the aetiology. Of the patients with elevated SSS pressures, there were focal pressure gradients (of at least 10 mmHg) at the junction of the middle and distal thirds of the transverse sinuses bilaterally in all patients. Venography demonstrated morphological abnormalities in these regions ranging from mild to severe focal narrowing. In some cases there appeared to be intraluminal filling defects and in others the sinus appeared smoothly tapered. These morphological characteristics were much more easily appreciated using venography than on conventional angiography. Shortly after a report from Karahalios et al. [78] suggested that venous sinus hypertension was the universal mechanism of PTS. In their study of 10 patients with PTS, 5 patients were found to have focal venous sinus obstruction. Later, in King et al.'s [85] second paper, a total of 21 patients with PTS for which no obvious cause was found (for example minocycline) were examined using venography and manometry. With the exception of 2 patients, SSS and CSF pressures followed each other closely and there were transverse sinus obstructions with significant pressure gradients.

The findings of Karahalios [78] and of King et al. [85, 86] of venous obstruction in PTC using DRCV were at odds with the conventional opinion regarding the pathophysiology of PTS. This probably reflects the fact that investigations of the venous sinuses in PTS were usually performed on the basis of four incorrect assumptions. First, the cause of venous sinus obstruction was thrombosis rather than stenosis or some other lesion. Second, the site of the obstruction was usually in the SSS. Third, static CT or MRI had sufficient sensitivity to detect the obstructing lesion. Fourth, when MRV was performed and was focused on the transverse sinuses, absence of flow in a transverse sinus was interpreted as a normal variant due to sinus hypoplasia or an artefact such as inflow turbulence.

The importance of the focus of the investigations and index of suspicion was evident from the report of Johnston et al. [74] who retrospectively reviewed 188 patients with PTS who had presented between 1968 and 1999. The group included 29 children. The overall incidence of venous sinus obstruction, they termed cranial venous outflow obstruction, was 19.7%. Of these 37 cases, an underlying cause of the obstruction could be identified in 20. Presumed aetiologies included thrombophilia (7 cases), trauma (2 cases), tumour (2 cases), and congenital jugular foraminal narrowing and infective internal jugular vein thrombosis with retrograde thrombosis. The remaining cases of idiopathic cranial venous outflow obstructions were all female patients. As cases had been accumulated over a 30 year period, investigations for PTS varied considerably as did the index of suspicion for venous sinus obstruction. In the first decade the incidence was only 4.2%, compared to 15% in the second and 31% in the third. In the final decade patients were likely to be investigated with MRI/MRV. While the patients in the first decade often underwent cerebral angiogra-phy rarely was the investigation focused on the venous sinuses which probably explains the low incidence of venous obstruction in that group. These authors also found the transverse and sigmoid sinuses to be the most common sites of obstruction (20/37 cases). In 11 cases obstruction was bilateral. Of the 9 patients with unilateral obstruction, the transverse sinus was definitely dominant in 6 cases and probably dominant in 2. In one case it was considered to be the non-dominant sinus although DRCV with manometry was not performed. Interestingly, only when the SSS became involved did obtundation or venous infarction become evident.

Two prospective case-control studies designed to investigate the prevalence of venous sinus obstruction in PTS have recently been published. Farb et al. [43] used a 3-D gadolinium enhanced MRV to examine the venous sinuses of 29 patients (age 37.2 years) with PTS and 59 control patients (age 60.3 years). The control group consisted of cancer patients that were undergoing MRI of the brain as a screening test for cerebral metastases. Patients with intracranial pathology were excluded from the study. The MRV of each patient was examined by 3 blinded radiologists. For each patient, an average combined venous conduit score (ACCS) of 2-8 was produced. For each side the patency of the transverse sinus was scored from 1-4 (1 = hypoplasia or severe stenosis and 4 = normal and patent). There was very high inter-observer reliability. With the exception of 2 patients, all had an ACCS of less than 5 (93.1%). Four of 59 controls (6.8%) had an ACCS of less than 5. Thus, an ACCS of less than 5 had a 93% specificity and sensitivity for PTS. For patients, there was no correlation between CSF pressure and ACCS. The morphology of the obstructing lesions amongst the PTS patients appeared extraluminal in 45 and intraluminal in 13 patients.

MRV was used by Higgins et al. [64] to examine 20 patients with PTS and 40 controls subjects. The control group consisted of patients who were recruited from patients presenting for MRI of another body region. Control patients were screened for headache and neurological disorders. Those with symptoms apart from very occasional minor headache were excluded. The PTS patients and asymptomatic controls were matched for sex and age. The MRVs were assessed for the existence of flow gaps in the transverse sinuses. No flow gaps could be seen in the transverse sinuses of any control patient on either side. In the PTS group, there were bilateral transverse flow gaps in 13 patients (65%). In only one patient were the sinuses normal bilaterally.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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