Understanding Carotid Artery Dissections
It is August of your intern year, and you are in the emergency department on one of your first shifts as a doctor. The waiting room is packed and you pull the next chart available.
Chief complaint: Neck pain after a motor vehicle accident 6 days ago
The patient is a 47 year old female with a past medical history of anxiety, depression, and fibromyalgia, who presents with bilateral neck pain that is worse on the left side after a car accident 6 days prior. She states that she was rear-ended at “around 25 mph” at a red light. She was a restrained driver. Front airbags were deployed. There was otherwise minimal damage and no one else was injured. The woman was able to self-extricate and she was ambulatory at the scene. She initially presented to another hospital for initial evaluation, where “some imaging was done,” and the patient was subsequently discharged home with a diagnosis of whiplash injury and prescription for 5 days of “pain meds.” Over the next few days, she noticed that the pain was not improving.
She describes the pain as constant, dull, worse on the left side of neck and non-radiating. Pain is exacerbated with movement and not improved with rest, ice, or NSAIDs. The pain is constant but tolerable. On further questioning, she states that she was advised to come in by her husband who felt that she “has looked different over the last couple of days.” Patient also endorses one episode of transient blurred vision, but denies weakness and headaches. She denies dysphagia, hoarseness, odynophagia. She denies tingling and numbness in her extremities. She is tolerating oral intake. She denies chest pain and shortness of breath. Review of systems is otherwise negative at this time.
Vital Signs - Within normal limits
General - Well appearing female found seated comfortably on chair adjacent to bed; texting; breathing well on room air; speaking in full sentences; in no acute distress
HEENT - Pupils 2 mm and reactive on right, 1 mm on left; Notable ptosis on left side
Neck - Mild tenderness to palpation of left anterior neck; No midline cervical spinal tenderness; no step offs; No swelling, ecchymoses, or carotid bruit
Lungs - Clear to auscultation bilaterally; good air-movement throughout; no crackles, wheezes, or rhonchi
Cardiac - regular rate and rhythm; no murmurs, rubs, or gallops
Abdomen - Soft, non-tender, non-distended; No seatbelt sign, no tenderness to palpation, no rigidity, rebound, or guarding
MSK - No deformities; motor function intact; 5/5 strength throughout
Neuro - CN II-XII grossly intact; sensory and motor function equal and intact bilaterally; no gait abnormalities
Psych - Appears anxious, but otherwise cooperative with exam and acting appropriately
Initial ED work-up involved general pre-op labs and CTA of head and neck.
The radiology resident calls to inform you that a critical finding of RIGHT-SIDED distal cervical internal carotid artery dissection was found. But does this make sense with the symptoms?
Like a good ER doc, you look through the scans and politely inform the radiologist that you believe you see findings suggesting a dissection of the LEFT internal carotid. He and his attending agree.
Neurosurgery is consulted for further recommendations. The patient is placed on ASA 81mg and admitted to the trauma service with neurosurgery following for a conventional angiography in the morning.
Upon chart review, The patient is discharged home the next day on aspirin and with no surgical or endovascular intervention. She has continued follow-up with neurosurgery every 3 months.
Diagnosis: Partial Horners syndrome, secondary to internal carotid artery dissection.
Take Away #1
Obtain a thorough history and trust your physical examination. What has changed since this patient’s initial accident that REALLY brought her in?
Subtle findings on physical exam can hold the key to a serious diagnosis in an otherwise well-appearing young woman.
Carotid artery dissections can present with many subtle physical exam findings including focal neurologic deficits, occulosympathetic palsy, cranial nerve palsies, cervical bruits, cervicothoracic seat belt sign, and neck hematomas/ecchymosis.
We should have a high index of suspicion for dissection in patients with unilateral neck pain, and should consider performing a thorough neurologic exam and HEENT exam on these patients.
Check the mechanism of injury. Anterior neck pain is uncommon finding and should be evaluated further.
Always read your own imaging, and don’t be afraid to politely discuss the findings with the reading radiologist if you have questions regarding their interpretation.
Take Away #2
Horners Syndrome - characterized by the classic triad of ptosis, anhydrosis, miosis.
Occurs due to the disruption of sympathetic trunk
Can be caused by issues with the primary neurons, with central causes such as brainstem tumors, vascular/demyelinating diseases, syringomyelia, lateral medullary syndrome, and diabetic autonomic neuropathies
Preganglionic causes include pancoast tumors, carotid and aortic aneurysms/dissections, neck lesions
Carotid Artery Dissections - Occur when there is a tear in the inner wall of the artery, allowing blood to enter tunica media, or intima of vessel. This can lead to an intramural hematoma formation, which can be a source of future embolic events or mass effect on surrounding structures.
This swelling can compress the sympathetic plexus which lies within the carotid sheath, leading to the above findings of an IPSILATERAL Horners syndrome.
In case of an ICA dissection, PARTIAL Horners syndrome can be found consisting of ptosis, and miosis, with a lack of anhydrosis as the sympathetic nerves responsible for sweating are closely associated with the external carotid artery, and not the internal carotid artery.
Take Away #3
Formerly, conventional angiography was the gold standard of diagnosis and would reveal findings of a false lumen. However, recent improvements in CTA/MRA have since become more useful given risks and invasiveness of conventional angiography.
In some institutions, MRA has been used as the mainstay diagnostic imaging when dissection is suspected. MRA with fat saturation would show intramural blood and mural expansion which is hallmark of diagnosis (semilunar hyperintensities surrounding hypointense circle). However, MRA has been shown to have decreased sensitivity for detecting dissection within the first 24-48 hours of symptom onset and is not always readily available. It is also less cost-effective than CT imaging
CTA of head and neck is nearly always sufficient for diagnosis.
Non contrast enhanced CT imaging has no utility as an adequate screening test or diagnostic test for carotid artery dissection, although it can show indirect findings suggestive of the diagnosis such as soft-tissue swelling or adjacent hematomas.
Previously, management of these patients was with anticoagulation with a heparin bridge to coumadin with a goal INR of 2.0-3.0, and 3-6 months of monitoring.
Recently, discussion has turned toward use of anti-platelet agents such as aspirin or plavix in management of carotid artery dissection.
In a recent multi-center randomized control study, the CADISS trial, patients with symptomatic extracranial carotid and/or vertebral dissections were randomized to heparin/coumadin group vs aspirin group and were monitored for recurrence of strokes or further disability. The study showed no statistical significance between the two groups when looking at outcomes over 12 months. In general, stroke risk was found to be as low as 2% within the first 12 months following dissection in this study.
Consultation with neurosurgery vs. vascular surgery for recommendations and follow-up should be obtained when managing these patients.
While there is no set criteria for endovascular treatment of carotid artery dissections over medical management with follow-up imaging over time, intervention is reserved for patients with continued symptoms following 3-6 months on appropriate medical management, worsening pain, or development of frank stroke.
Matthew Vitale, MD is a current first year resident at Stony Brook Emergency Medicine. He can be reached on Twitter @MattVitale23.
Goyal, Manu S, and Colin P Derdeyn. “The Diagnosis and Management of Supraaortic Arterial Dissections.” Current Opinion in Neurology, vol. 22, no. 1, 2009, pp. 80–89., doi:10.1097/wco.0b013e328320d2b2.
Markus, Hugh S., et al. “Antiplatelet Therapy vs Anticoagulation Therapy in Cervical Artery Dissection.” JAMA Neurology, vol. 76, no. 6, 1 June 2019, p. 657., doi:10.1001/jamaneurol.2019.0072.
Edited by Bassam Zahid, MD