The venous sinuses are important in CSF absorption, with arachnoid villi invaginating the sagittal sinus in particular. Thrombotic occlusion of the venous system occurs with —head trauma
. Cortical veins
Straight sinus ^jjF^ A^' lT ______Superior sagittal sinus Ï___Inferior
Great I sagittal sinus
—pregnancy, puerperium and pill —coagulation disorders —malignant meningitis —miscellaneous disorders e.g. sarcoid, Beçhets Improved imaging (MRI) has resulted in increased recognition. Venous infarction accounts for 1% of all 'strokes'.
cerebral vein -
cerebral vein -
Superficial middle cerebral vein
The cerebral venous system
Superior sagittal and lateral sinus thrombosis (85% of cases)
Impaired CSF drainage results in headache, papilledema and impaired consciousness. Venous infarction produces seizures and focal deficits (e.g. hemiplegia). Diagnosis is suggested by venous (nonarterial territory) infarction and 'empty delta' sign (following contrast the wall of the sinus enhances but not the central thrombus on CT) and confirmed by occlusion of filling deficit on MR angiography/venography. Outcome is variable; benign intracranial hypertension may develop (p. 364). A thorough search for causation — coagulation screen, drug history and underlying systemic illness - essential. Treatment:
The role of heparin remains uncertain and is currently being evaluated. Deep cerebral venous thrombosis (10% of cases)
This produces venous infarction of the basal ganglion and other subcortical structures. Presentation with similar features; diagnosis can only be established by imaging (CT/ MRI and MRV). The role of heparin is again uncertain.
Cavernous sinus thrombosis (5% of cases)
Commonly results from infection spreading from the jaw through draining veins or paranasal sinuses. Painful ophthalmoplegia, proptosis and chemosis with oedema of periorbital structures are associated with facial numbness and fever. The disorder may be bilateral. Base diagnosis on clinical suspicion supported by venography. Treatment with ------------------antibiotics and if indicated, sinus drainage.
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