The case discussed here illustrates the clinical presentation and diagnostic complexities of CVT. Two days before coming to the ED, the patient presented to an outside facility and underwent a workup for nonspecific symptoms (eg, confusion, headaches). Due to the nonspecific presentation associated with CVT, a detailed history is imperative to distinguish symptoms suggesting increased intracranial pressure, such as headaches worse when lying down or present in the morning, with a high clinical suspicion of CVT. The ability to attain these specific details leads clinicians toward obtaining the necessary imaging studies for potential CVT patients, and may prevent delay in diagnosis and treatment. The thrombus in CVT initially consists of deoxyhemoglobin and appears on MRI as an isointense signal on T1-weighted images and a hypointense signal on T2-weighted images; over subsequent days, the thrombus changes to methemoglobin and appears as a slightly hyperintense signal on both T1- and T2-weighted images. 24
During this phase, there are some false negatives, as the thrombus can be mistaken for imaging artifacts, hematocrit elevations, or low flow of normal venous blood. Given the clinical findings and imaging studies, it is essential to distinguish CVT from other benign etiologies. Earlier diagnosis and initiation of anticoagulation therapy may have precluded the small amount of localized ischemic changes in this patient’s right thalamus, thus preventing the mild sensory loss in the left upper extremity. With the variable and nonspecific clinical presentations and the difficulties in identifying CVT with first-line imaging, progression of thrombus formation may lead to severe focal neurologic deficits, coma, or death.
Using CT imaging studies to compare the blood in the draining cerebral sinuses with the blood in the arterial system can help distinguish CVT from other etiologies of hyperdense abnormalities, such as increased hematocrit or decreased flow. Retrospective close examination of the present patient’s noncontrast CT images of the head and brain revealed slight hyperdensity in the cerebral sinuses compared with the arterial blood, suggesting the presence of thrombus formation in the cerebral veins. As CT is often the first study used to evaluate the nonspecific clinical presentations of these patients, identifying subtle signaldensity differences between the arterial and venous systems could guide physicians in identifying CVT earlier.
The authors reiterate the importance of meticulous imaging interpretation in light of the entire clinical picture: In these patients, it is imperative to have a high index of clinical suspicion for CVT in order to prevent more serious complications, such as ischemic or hemorrhagic stroke.