Diagnosis and Management of Lateral Sinus Thrombosis

Diagnostic Approach

The American College of Radiology recommends venographic imaging with either CT venography (CTV) or MR venography (MRV) following a plain CT or MRI for the initial evaluation of lateral sinus thrombosis, as a negative plain CT or MRI alone does not rule out the condition 1
A venographic study (either CTV or MRV) should be performed when lateral sinus thrombosis is suspected, even if the plain CT or MRI is negative, due to its high sensitivity and specificity for detection of cerebral venous thrombosis 1
CTV of the head is a useful, rapid initial evaluation with high sensitivity and specificity for detection of cerebral venous thrombosis, according to the Journal of the American College of Radiology 3

On direct cerebral venography, intraluminal thrombus appears as a filling defect within the lumen (nonocclusive thrombosis) or as complete nonfilling (occlusive thrombosis), which can demonstrate a "cupping appearance" within the sinus 1
Noncontrast CT may show sinus hyperdensity in some cases, although only 30% of noncontrast head CT examinations are abnormal in lateral sinus thrombosis, and contrast-enhanced CT may demonstrate the "empty delta sign" 3
Gradient echo T2 susceptibility-weighted MR images can improve the accuracy of diagnosis, as recommended by the Stroke journal 1

Anatomic variants of normal venous anatomy may mimic sinus thrombosis, including sinus atresia/hypoplasia, asymmetrical sinus drainage, and normal sinus filling defects, which can be identified using angiographic examination 1
Flow gaps are commonly seen on time-of-flight MRV images, which can affect interpretation, and direct cerebral venography may be difficult to interpret due to retrograde flow of contrast 1

Immediate initiation of therapeutic anticoagulation with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) is recommended upon diagnosis, even in the presence of intracranial hemorrhage, as the benefits of preventing thrombus progression outweigh bleeding risks 4
Chemical thrombolysis should be reserved for severe cases with neurological deterioration despite anticoagulation, and catheter cerebral angiography can be useful in patients with inconclusive CTV or MRV 4
Direct endovascular thrombolysis involves catheter-directed delivery of thrombolytic agents directly into the thrombosed sinus, as recommended by Praxis Medical Insights 4

An early follow-up CTV or MRV is recommended in patients with persistent or evolving symptoms despite medical treatment, and a follow-up CTV or MRV at 3 to 6 months after diagnosis is reasonable to assess for recanalization of the occluded sinus 1
Continuous neurological assessment is essential during treatment, and patients with previous lateral sinus thrombosis who present with recurrent symptoms suggestive of thrombosis should undergo repeat CTV or MRV 4