Causes of Multiple Artery Dissections in the Brain
Multiple cerebral artery dissections result from a combination of underlying connective tissue disorders, fibromuscular dysplasia, and trauma—with approximately half occurring spontaneously or after trivial injury, particularly in younger patients.
Primary Etiologic Categories
Connective Tissue Disorders
The following genetic and structural arteriopathies predispose to multiple dissections 1:
- Fibromuscular dysplasia (FMD) is the most common association, present in approximately 15% of dissection cases 1, 2
- Marfan syndrome causes abnormal collagen formation affecting arterial wall integrity 1
- Ehlers-Danlos syndrome type IV specifically increases dissection risk through vascular fragility 1
- Osteogenesis imperfecta and other genetic conditions with abnormal collagen formation 1
- Bicuspid aortic valve is observed in 1-5% of patients with carotid dissection 1
Traumatic Causes
Mechanical injury accounts for approximately half of cases 1:
- Significant head and neck trauma from motor vehicle accidents or direct injury 1
- Sudden or excessive neck movement including hyperflexion/hyperextension 2, 3
- Minor trauma including chiropractic manipulation 2
- Penetrating trauma to the neck region 1
Spontaneous Dissections
Approximately 50% of dissections occur spontaneously or after trivial injury without identifiable major trauma 1. These cases typically involve underlying but undiagnosed connective tissue abnormalities 4.
Pathophysiologic Mechanism
The dissection process begins with an intimal tear that initiates an intramural hematoma 1:
- Subintimal dissection tends to cause stenosis and thromboembolism 1
- Subadventitial dissection results in aneurysmal degeneration 1
- Ischemic stroke occurs primarily through thromboembolism rather than hemodynamic compromise 1
- Intracranial dissections (particularly vertebrobasilar) carry risk of subarachnoid hemorrhage in addition to infarction 1
Clinical Context and Risk Factors
Age and demographics matter significantly: Cerebral artery dissection accounts for approximately 2% of all ischemic strokes but up to 15-20% of ischemic strokes in patients under 45 years 1, 4.
Additional risk factors include 1, 4:
- Amphetamine abuse
- Multiple vascular bed involvement when FMD is present, potentially affecting coronary, renal, and cerebral arteries simultaneously
Critical Diagnostic Consideration
When multiple dissections are present, actively search for underlying connective tissue disorders or FMD through detailed family history, physical examination for syndromic features (joint hypermobility, skin changes, cardiac abnormalities), and vascular imaging of other arterial beds 1, 4, 5. The presence of multiple dissections strongly suggests an underlying arteriopathy rather than isolated trauma 6, 5.
Important caveat: None of these underlying connective tissue conditions are currently amenable to curative treatment, but their identification guides prognosis, family counseling, and surveillance strategies 1.