Cervical dissections (CD) of the arteries—small tears in the layers of the arterial walls in the neck—are an important cause of stroke in young and middle-aged patients. CD can result in ischemic stroke if blood clots form after a trivial or major trauma in the neck and later cause blockages to the blood vessels in the brain. “CD accounts for just 2% of all ischemic strokes but 8% to 25% of strokes in patients younger than age 45,” says José Biller, MD, FAAN, FACP, FAHA. “The annual incidence, however, is likely underestimated because asymptomatic CD often goes undiagnosed.”
Currently, the underlying pathology for spontaneous CD is unknown, but several factors have been linked to CD (Table 1). Dissections can be either spontaneous or traumatic, and their severity can vary. Research has shown that mechanical forces often play a role in a considerable number of CDs. “Most dissections involve some form of trauma, stretching, or mechanical stress,” says Ralph L. Sacco, MD, MS, FAHA, FAAN. These dissections can also occur with cervical manipulative therapy (CMT), various sporting activities, whiplash injuries, sudden neck movements, and violent vomiting or coughing, even if these events are deemed inconsequential by patients. Although CMT techniques vary, maneuvers often extend and rotate the neck, and some involve a forceful thrust.
In 2014, the American Heart Association (AHA) released a scientific statement on CD and its association with CMT. “The statement reviews the current state of evidence on diagnosing and managing CDs and their statistical association with CMT,” says Dr. Sacco, who co-chaired the AHA writing committee that developed the scientific statement. “The association between CD and CMT has been identified in case control studies, but these analyses aren’t designed to prove cause and effect. It’s still unclear whether other factors could account for the apparent relationship.”
Challenging to Diagnose & Treat
According to Dr. Biller, who also co-chaired the AHA scientific statement writing group, the relationship between neck manipulation and CD is difficult to evaluate because patients who are beginning to have these dissections may seek treatment to relieve neck pain. “This is a common symptom of CD that can precede symptoms of stroke by several days,” he says. A diagnosis of CD depends on a thorough neurologic history, physical examination, and targeted ancillary investigations (Table 2). Mechanical forces can lead to intimal injuries of the vertebral arteries and internal carotid arteries, potentially resulting in CD. Disability levels can vary among patients with CD; some have good outcomes, whereas others suffer more serious neurological sequelae.
“For clinicians, the key is to ensure that patients understand the associations between CD and CMT before undergoing neck manipulation,” says Dr. Biller. “Unfortunately, CD symptoms are often categorized as a musculoskeletal problem rather than a potential predictor of stroke.” Dr. Sacco adds that patients should be educated to seek emergency care if they develop neurological symptoms after neck manipulation or trauma. “This includes symptoms like pain in the back of the neck or head as well as dizziness or vertigo, double vision, unsteadiness when walking, slurred speech, and nausea and vomiting,” he says. “It’s also important for patients to tell their physicians if they’ve recently had neck trauma or neck manipulation so that a thorough evaluation for CD can be performed.”
According to the AHA scientific statement, there are no currently available evidence-based guidelines that endorse any best management strategies for CDs. Antiplatelet and anticoagulant treatments are both used for prevention of local thrombus and secondary embolism (Table 3), but more research is needed to determine ideal candidates for these therapies.
More to Come
Dr. Biller and Dr. Sacco agree that more research on the association between CD and CMT is warranted. “We need a better understanding of the components of CD and the role of trauma in these dissections,” says Dr. Biller. “Clinical studies must also further explore the role of preventive therapies.” Dr. Sacco anticipates that future analyses will also investigate strategies for improving the diagnosis of CD with MRI and other diagnostic modalities. “There is no single test that can be seen as the gold standard,” he says. “It will also help to discover specific factors that predispose patients to CD. As this research emerges, there is hope that we can improve upon the diagnosis and treatment of CD and enhance outcomes among the younger patients who are at risk for these events.”