In vascular dissection, the layers of an arterial wall separate. Usually, a tear first occurs in the inner vessel wall. As a result, blood at high pressure enters the middle vessel wall and forms an additional cavity. This false channel narrows the normal path of blood flow and can completely occlude the vessel.
Pathophysiology
Dissection in an arterial vessel is usually triggered by a tear in the tunica intima with subsequent bleeding between the intima and media.
Diagnostics
Patients with a significant trauma mechanism should be screened for an intracranial vascular dissection using a CT angiography or MR angiography. The gold standard in the definitive diagnosis of intracranial and extracranial vascular dissections is digital subtraction angiography. Angiographically, dissection often shows narrowing of the vessel, an irregular vessel appearance, an intimal flap, a thrombus, or a double lumen. Intracranial vascular dissections have a high risk of ischemic stroke because a thrombus can easily form at the injured vessel wall.
Dissection of the internal carotid artery
Dissections of the internal carotid artery can be triggered by trauma. Pathognomonic for ICA dissection are miosis and ptosis.
Clinical presentation of spontaneous ICA dissection | Frequency (%)[^1] |
Focal cerebral ischemia | 76 % |
Headache | 59 % |
Oculosympathetic palsy | 30 % |
Bruit | 25 % |
Amaurosis fugax | 10 % |
Syncope | 4 % |