Sagittal Sinus Thrombosis: Clinical Features and Imaging

Sagittal sinus thrombosis is a rare condition that is often associated with one of the hypercoagulable states listed in Table 10.5.

The condition occurs with increased frequency in pregnant women and within the first few weeks post partum.

Obstruction of venous drainage usually causes elevated intracranial pressure.

Back pressure in cortical veins can cause parasagittal hemorrhages.

In addition, the increased venous pressure can decrease cerebral perfusion, leading to infarcts.

Seizures are common.

Patients often have headaches and papilledema, and they may have depressed level of consciousness.

The superior sagittal sinus can normally be seen as a triangular region on axial CT and MRI scan images.

In sagittal sinus thrombosus, there may be a central, darker-filling defect, called the empty delta sign.

More subtle radiological signs of sagittal sinus thrombosus include increased density of the sagittal sinus on CT due to coagulated blood, or increased T1 signal on MRI.

In suspected sagittal sinus thrombosus, regardless of whether these subtle radiological findings are present, a more definitive study should be performed, such as magnetic resonance venography (MRV) or a conventional angiogram.

Treatment usually involves anticoagulation therapy, although this is controversial when hemorrhage has occurred.

Seizures (see KCC 18.2) and elevated intracranial pressure (see KCC 5.3) should be treated as well, when present.