Craniocervical arterial dissection in children: diagnosis and treatment

Abstract

Diagnosis of craniocervical arterial dissection (CCAD) in children begins with a careful history and physical in a child with a transient ischemic attack (TIA) or arterial ischemic stroke (AIS). The extent of radiologic evaluation for suspected CCAD is based upon careful consideration of the risks associated with the best imaging techniques, weighed against the benefits of enhanced vascular imaging with better diagnostic sensitivity. Although conventional angiography (CA) and CT angiography (CTA) have a higher sensitivity than magnetic resonance angiography (MRA), they are accompanied by risks: for CA, femoral hematoma, femoral arterial pseudoaneurysm, recurrent AIS, and radiation exposure; for CTA, radiation. For children (non-neonates) with suspected CCAD, MRI with MRA is recommended as the first-line imaging study. MRI usually includes diffusion-weighted, FLAIR, and T1 images of the brain, and T1 or T2 fat-saturation axial imaging through the neck. MRA should include 3D time-of-flight MRA of the head and neck (from the aortic arch through the circle of Willis). Contrast-enhanced MRA should be highly considered in neck imaging. If MRI/MRA is equivocal, CCAD is strongly suspected but not detected on MRI/MRA (especially in the posterior circulation), or the child has recurrent events, additional imaging of the craniocervical vasculature is likely warranted. Individual clinical circumstances warrant careful, case-by-case consideration. Treatment of CCAD in children is challenging and differs for intracranial and extracranial dissections. In extracranial CCAD, we most commonly use anticoagulation for 6 weeks to 6 months in patients with TIA or AIS. Typically, unfractionated heparin is used in the acutely ill patient at heightened risk for bleeding (because of its short half-life), whereas low-molecular-weight heparin (LMWH) or warfarin are reserved for the stable patient. If the history is suspicious for dissection (head and neck trauma, recent cervical chiropractic manipulation, recent car accident, or neck pain), we consider treatment for dissection even with normal MRI/MRA. For patients with CCAD with a stroke size greater than one third to one half of the middle cerebral artery territory (or other bleeding risk factors) and extracranial CCAD, in whom there is concern about heightened risk for hemorrhagic conversion, we commonly use aspirin therapy during the acute phase. Regardless of their treatment in the initial weeks to months, we subsequently treat all patients with aspirin for 1 year after their event, and sometimes longer if they have other risk factors. Interventional techniques, such as extracranial cerebral arterial stent placement or selective occlusion, are understudied in children. Interventional techniques are typically reserved for patients who fail aggressive medical management and have recurrent TIA or AIS. The diagnosis and treatment of intracranial dissection is extraordinarily challenging in children, in whom inflammatory intracranial arteriopathies are common. When intracranial arteriopathy is clearly associated with dissection, the clinician should look for the presence of subarachnoid hemorrhage and/or dissecting aneurysm. Treatment decisions should be made by a multidisciplinary pediatric stroke team, given the lack of data in this area. Intracranial cerebral artery stent placement carries high risk and is not recommended for intracranial CCAD in children. Most importantly, we educate all children with CCAD and their parents about the paucity of evidence in the treatment of this disease, the risks of enhanced imaging techniques such as CTA or CA, and the challenges involved in weighing the risks of aggressive therapies and interventions against the costs of unclear diagnosis and potentially ineffective treatments. We also educate our patients with CCAD about the signs and symptoms of recurrence and the importance of emergent evaluation.

Figure 1

Selected cases of childhood spontaneous craniocervical arterial dissection (CCAD). Case 1. 12-year-old girl with transient ischemic attack (TIA) and CCAD. One hour after incidental neck trauma, the patient had left facial droop that spontaneously resolved. 1a Maximum intensity projection (MIP) images using time of flight (TOF) magnetic resonance angiography (MRA), ordered at the initial neurology visit (1 month later) shows slow flow through a small left vertebral artery, with abrupt cutoff at C2-C3 (white arrow). 1b T1 fat saturation images reveal a “crescent sign” at C1–C2 (inset). MRI of the brain was normal. Case 2. 4-year-old boy with dissecting aneurysm and right visual field cut. MRI/MRA and CT angiography showed left posterior cerebral artery infarct but were equivocal for the diagnosis of CCAD. 2a Conventional angiography revealed a dissecting aneurysm of the left vertebral artery at the C2-C3 level (white arrow). The patient failed medical management with aspirin and low-molecular-weight heparin. 2b He has been symptom-free for 14 months after interventional coiling of left vertebral artery (black arrow).

Figure 2

Algorithm for the initial radiologic evaluation of suspected spontaneous craniocervical arterial dissection (CCAD). Evaluation begins with brain MRI with diffusion-weighted imaging (DWI), time-of-flight (noncontrast) MR angiography (MRA) of the head, and contrast-enhanced MRA of the neck with a T1 fat-saturated sequence. AIS arterial ischemic stroke; CA catheter angiography; CTA CT angiography; TIA transient ischemic attack.