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Request for Help: Recovering from Dissection of Carotid Artery
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This is probably a long shot but I was hoping that I might be able to find someone who's gone through a similar situation.

To start, I had an acute injury on the bike where I dissected my carotid artery, a subsequent clot and then a minor stroke. As of this moment, no long-term damage so I should be fine.

However, my neurosurgeon is incredibly busy so getting answers to all of my questions has been a bit challenging. More importantly, talking to a triathlete who has already gone through this would greatly help put things into perspective.

Given my condition showed no chronic issues, ideally, I would like to talk to someone who recovered from an acute injury since I'm told that full recovery follows different paths.

Again, I would appreciate any help whatsoever. Feel free to PM me.

Thanks, Chris
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Re: Request for Help: Recovering from Dissection of Carotid Artery [lakerfan] [ In reply to ]
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Can you go into more detail about the dr's explanation for how this happened? What I got from your thread was you were in aero, hit a pot hole and that was it. There is nothing more to it than that? Implies we are all at risk of something like this everytime we ride. Im glad you are ok and recovering, it's just so shocking.
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Re: Request for Help: Recovering from Dissection of Carotid Artery [ntc] [ In reply to ]
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ntc wrote:
Can you go into more detail about the dr's explanation for how this happened? What I got from your thread was you were in aero, hit a pot hole and that was it. There is nothing more to it than that? Implies we are all at risk of something like this everytime we ride. Im glad you are ok and recovering, it's just so shocking.


Absolutely. I'm assuming you probably haven't read this thread (starting at post #5) which is where I started to tell my story:

Here

To start, it's probably important for you to understand that I am a natural born skeptic -- probably to the point where I irritate the shit out of people at times. Point being, I would guess the probability of what happened to me to be on the order of something like .001% or less. My initial assumption prior to talking to my docs post surgery was that I was a ticking time bomb, i.e., I had some sort of chronic condition that was just waiting to be exposed. This is clearly the most intuitive result given that kind of probability. So, I definitely needed some serious convincing here.

I will say the pothole was the worst I have hit in my 15+ years of serious cycling. Again, the hit was so significant it did affect my aerobars but that's not an uncommon occurrence either. However, being in a relatively aggressive aero position, your neck is probably the most vulnerable thing in this situation.

Post surgery the docs made it crystal clear that I had no signs of any chronic condition, e.g., partial blockage due to plaque buildup, etc, and that my dissection was due to an acute injury, i.e., trauma to the neck area which is almost always due to some kind of whiplash. They thought I had crashed. I kept telling them that I never crashed. The only significant thing that happened to me was when I hit the pothole.

Now, I do remember that I hit the pothole right after passing someone. That means I was first moving to the right looking back over my right shoulder to make sure I was clear of the rider. This is something I always do (mostly out of courtesy and partly out of safety, of course). I did spot the pothole a small fraction of a second before I hit it but my head was possibly in motion moving from the right side towards the front. However, I'm just not sure if my head had completely rotated to the front yet. These kinds of details are critical to understand whether my head position and therefore my neck might have been quite vulnerable at the time of impact. I just don't know.

Another thing to note:

This was my first race back in over 5 years. Now, as far as my cycling is concerned, I managed to get my FTP back to where it was when I took my break from the sport 5 years ago. However, I started training hard/consistent again around August of last year. So, was that enough time to rebuild strength in my neck again to accommodate a return to an aggressive aero position? I thought it was but I'm also 53 years old now so maybe I should have been more conservative. That road was absolutely brutal so maybe it was a cumulative effect where the pothole caused some initial damage or weakness and things got worse from there?

Trust me, I'm as freaked out about this as anyone so the word "shocking" is certainly appropriate. However, let's put things into perspective a little bit:

The probability that you die in an accident driving to work every day is far greater than what happened to me.

Lastly, I have definitely received a fair number of emails/messages from people who say that I'm alive due to some kind of miracle (they actually use the word "miracle") and ironically most of them have come from nurses, first responders, etc who claim to have experience seeing people in my situation before. I just feel like several people made really good, highly educated decisions that *might* have saved my life.

Hope that helps. Unfortunately, there's no easy/simple answer here but I tried to give you what I think is a relatively objective perspective for someone in my position.








Last edited by: lakerfan: May 19, 18 15:53
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Re: Request for Help: Recovering from Dissection of Carotid Artery [lakerfan] [ In reply to ]
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I went ahead an read your other post about this incident and am shocked. It's great you are alive and doing well. For the sake of clarity, you are reporting a carotid artery dissection that resulted in a TIA from hitting a pothole that didn't force you to crash? Was your next is some form of extreme rotation? I've read about these types of injuries in the chiropractic literature but only occur in extreme rotation and upper cervical extension with an external force applied. Even then, the likelihood is fractions of a percent. What is your biological/genetic risk factor? All your other blood metrics are in line? Blood pressure? Cholesterol? Triglicerides? Either way, you need cardiac rehab after an even like that. Are you currently on eliquis or Coumadin? Are you at significant risk for this happening again given some type of genetic/biological predisposition? I'm shocked to hear about something like this happening given the incidence is so extremely low. If you are up for it, could you share more info?
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Re: Request for Help: Recovering from Dissection of Carotid Artery [AndrewL] [ In reply to ]
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AndrewL wrote:
I went ahead an read your other post about this incident and am shocked. It's great you are alive and doing well. For the sake of clarity, you are reporting a carotid artery dissection that resulted in a TIA from hitting a pothole that didn't force you to crash? Was your next is some form of extreme rotation? I've read about these types of injuries in the chiropractic literature but only occur in extreme rotation and upper cervical extension with an external force applied. Even then, the likelihood is fractions of a percent. What is your biological/genetic risk factor? All your other blood metrics are in line? Blood pressure? Cholesterol? Triglicerides? Either way, you need cardiac rehab after an even like that. Are you currently on eliquis or Coumadin? Are you at significant risk for this happening again given some type of genetic/biological predisposition? I'm shocked to hear about something like this happening given the incidence is so extremely low. If you are up for it, could you share more info?


No worries. These are all questions I would expect to be asked.

I know I'm going to sound like a broken record but this is why I keep emphasizing it was an acute injury. Again, our family made the exact same assumption after I came out surgery, i.e., that I had some kind of chronic issue or genetic predisposition. However, I don't.

As expected in this situation, I do have to take Plavix but only for 3 months. That's it. I've seen and have discussed all of my blood tests with the docs, which was a combination of my neurosurgeon and a number of neurologists. They all said the same thing which is that I have no signs whatsoever of any chronic condition and all my results indicate that I have no biological predisposition. My blood pressure, cholesterol, etc are all good/excellent. This is also consistent with past test results, e.g., life insurance exam, etc. In fact, the worst result I've ever had at any one point in the past was a low HDL result that corresponded with a period of very high training volume. A retest about a month later showed excellent results.

Is it possible they missed something? Sure, it's possible but their results are consistent with previous test results. Keep in mind, I also have zero family history here. Thankfully, there just seems to be overwhelming evidence that I'm incredibly healthy overall.

I suppose it's also important to note that I was out of the hospital in record time. I went into surgery Sat afternoon, left ICU Mon afternoon and left the hospital the next morning. I actually wanted to leave a day earlier but they said that would be impossible. As it was, nobody had been in ICU for that type of injury for as little time as I was there. After the first day in ICU they were telling me I could easily be there a week or two. That was 2 weeks ago now and I've already been on at least five 5 - 7 mile walks.

Regarding your comment about chiro-related injuries of this nature, interesting enough, that conversation came up with one of the neurologists. That neurologist said the most common dissection they see due to an acute injury is from a chiro neck adjustment. In fact, in her experience, it's so common that she encouraged me to never get an neck adjustment from a chiro. I know others might be saying, "WTF," but I'm just repeating what the neurologist told me.

Last thing, I've been told that I can start light training again after 2 weeks, which seems about as aggressive as it gets. However, this is where the guidance gets too fuzzy for me. Things happened so fast that I didn't really get the chance to absorb my situation and therefore ask all of the questions I needed to ask. My discharge paperwork makes statements like "No Ironmans until after I'm off Plavix" but it doesn't help me quantify the risk of training after 2 weeks. It seems to emphasize the risk of bleeding that comes with being on Plavix but what about the risk of getting my HR elevated too early? If I'm riding on a trainer then the risk of crashing is obviously reduced significantly.

After almost a week I'm still waiting for my neurosurgeon to respond to a slew of follow-up questions. Apparently he's incredibly picky about who communicates with his patients but he's also so busy that he can't respond in what I consider to be a timely manner. I'm just hoping to have a more dynamic conversation with someone who's been in a similar situation or possibly another neurosurgeon/neurologists.

As far as the probability of this happening is concerned, well, I suppose it's like winning the lottery. Someone has to win and in this case it was me. Unfortunately, this isn't one of those lotteries you want to win. Probability is a tricky beast to get your head around at times.
Last edited by: lakerfan: May 20, 18 11:39
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Re: Request for Help: Recovering from Dissection of Carotid Artery [AndrewL] [ In reply to ]
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Btw, I just want people to know that I truly appreciate these kinds of questions. I want people to challenge me to ensure that I'm doing my due diligence here. I realize that my biases are going to push me towards a result that is a best-case scenario. However, I'm only interested in understanding the truth whether that ends up revealing some kind of chronic issue or genetic predisposition or not.

At this point, the evidence seems overwhelming which probably makes some people nervous because if it can happen to me then they'll certainly think it can happen to them.
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Re: Request for Help: Recovering from Dissection of Carotid Artery [lakerfan] [ In reply to ]
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lakerfan wrote:
This is probably a long shot but I was hoping that I might be able to find someone who's gone through a similar situation.

To start, I had an acute injury on the bike where I dissected my carotid artery, a subsequent clot and then a minor stroke. As of this moment, no long-term damage so I should be fine.

However, my neurosurgeon is incredibly busy so getting answers to all of my questions has been a bit challenging. More importantly, talking to a triathlete who has already gone through this would greatly help put things into perspective.

Given my condition showed no chronic issues, ideally, I would like to talk to someone who recovered from an acute injury since I'm told that full recovery follows different paths.

Again, I would appreciate any help whatsoever. Feel free to PM me.

Thanks, Chris

Chris
As you alluded to, you are a rare case. And in medicine, it's 'never good to be a good case'. Sorry that this happened to you.

Carotid artery dissection during any sporting activity is very rare. I have taken care of many people with various dissections-usually trauma related and in some ways the stress of sports is a sort of trauma. In some cases, there is underlying pathological risk that was unknown at the time of the occurrence but that does not seem to be the case with you.

Your questions are best answered by your doctors who know you best. But it seems like it was an acute injury based on what I read in the threads.

Don't try to wrap your head around it too much-trauma is trauma. I've seen people that fall 15 feet and are perfect, fine, no injuries. I've seen people who had an excavator fall on them an get a minor fracture. Others, slip and fall 1 foot and have multiple fractures of multiple bones. Trauma usually doesn't crack a blood vessel, but it can happen. Traumatic aortic dissection from MVA's have killed many drivers. One of my patients about 20 years ago crashed her car and hit her chest on the steering wheel and dissected her LAD and needed an urgent coronary stent. There was great debate about which came first: the MI or the MVA...

You are the first person I've personally heard of who had a carotid artery dissection on a bike. (*and I've certainly heard dozens of stories of strokes from manipulations from chiros...)

From 'Up to Date': Which may be a bit too clinical...

Spontaneous cerebral and cervical artery dissection: Clinical features and diagnosis
Author:David S Liebeskind, MD Section Editor:Scott E Kasner, MD Deputy Editor:John F Dashe, MD, PhD
Contributor Disclosures

All topics are updated as new evidence becomes available and our peer review process is complete.

Literature review current through: Apr 2018. | This topic last updated: Aug 25, 2017.



INTRODUCTION — Arterial dissections are a common cause of stroke in the young, but may occur at any age. Dissection occurs when structural integrity of the arterial wall is compromised, allowing blood to collect between layers as an intramural hematoma.

This topic will review the pathophysiology, etiology, clinical features, and diagnosis of spontaneous cerebral and cervical artery dissection. The treatment and prognosis of cervicocephalic dissection is reviewed in detail separately. (See "Spontaneous cerebral and cervical artery dissection: Treatment and prognosis".)

Other mechanisms of ischemic stroke and subarachnoid hemorrhage are discussed elsewhere. (See "Ischemic stroke in children and young adults: Etiology and clinical features" and "Etiology, classification, and epidemiology of stroke" and "Clinical manifestations and diagnosis of aneurysmal subarachnoid hemorrhage" and "Nonaneurysmal subarachnoid hemorrhage".)

PATHOPHYSIOLOGY — Separation of the arterial wall layers results in dissection. A false lumen arises in the space where blood seeps into the vessel wall (figure 1). Hemorrhage may be due to an intimal tear or result from rupture or other pathology in the vasa vasorum [1,2]. Subintimal dissections cause luminal stenosis or occlusion whereas subadventitial dissections largely result in dissecting aneurysm formation (figure 2). False lumen extension back into the true lumen can form a double channel for blood flow in the artery.

Neurologic sequelae of extracranial and intracranial dissection may result from cerebral ischemia due to thromboembolism, hypoperfusion, or a combination of both. However, thromboembolism rather than hypoperfusion is considered the major cause of ischemic symptoms [3,4]. In addition, dissection and aneurysmal dilatation may cause local symptoms from compression of adjacent nerves and their feeding vessels, resulting in pain, partial oculosympathetic paresis (Horner syndrome), lower cranial neuropathies [5], or cervical nerve root involvement. Pain is thought to be caused by activation of nociceptors from distension of the vessel wall due to the hematoma [6].

In a minority of cases, dissection of intracranial arteries, which lack an external elastic lamina and have only a thin adventitial layer, can lead to vessel rupture with subarachnoid hemorrhage.

Extracranial internal carotid dissection typically occurs 2 cm or more distal to the carotid bifurcation, near or adjacent to the skull base [7]. Intracranial carotid dissection is most frequent in the supraclinoid segment [8]. Vertebral artery dissection most commonly affects the V3 segment at the C1 to C2 level.

Multiple simultaneous cervicocephalic dissections are found in 13 to 22 percent of cases [9-12], and may occur more often in women than men [10,11,13]. Three or more dissections occur in approximately 2 percent of cases [13]. Although evidence is limited to small patient numbers, multiple simultaneous dissections are not typically associated with a known underlying predisposition to dissection [13]. Rather, most cases may be due to a transient vasculopathy following minor trauma or infection, with ischemia manifest in only one of the downstream arterial territories.

Pathology — Histopathologic specimens of dissected arteries are rarely obtained, yet examination may reveal intramural hemorrhage, disruption of the subintimal plane and less frequent separation of the media and adventitia (picture 1) [14]. In a case-control study, superficial temporal artery specimens obtained by biopsy or autopsy from 14 patients with spontaneous cervical artery dissection showed pathologic changes involving mainly the adventitial and medial layers, with vacuolar degeneration and fissuring along with capillary neoangiogenesis and microscopic erythrocyte extravasation into connective tissue [2]. In contrast, only one of nine control arteries obtained from accident victims showed pathologic changes in the outer arterial walls.

There is a high prevalence of ultrastructural connective tissue abnormalities in patients with apparently sporadic cervicocephalic artery dissection [15-17]. These abnormalities consist primarily of composite fibrils within collagen bundles and fragmented elastic fibers.

ETIOLOGY — As noted above, dissection occurs when the structural integrity of the arterial wall is compromised, allowing blood to collect between layers as an intramural hematoma. Common causes include various degrees of trauma or spontaneous events, with underlying predispositions in some cases. Intrinsic factors related to vessel wall integrity and extrinsic factors, including minor trauma, both contribute to dissection formation. Dissection can also result from major head and neck trauma, but most dissections occur spontaneously or after minor or trivial injury.

Minor trauma and other triggers — Observational data suggest that trauma or other potential mechanical triggering events, typically mild in nature, are associated with cervical artery dissection in up to 40 percent of cases [18]. Physical activities associated with dissection include skating [19], tennis [20,21], basketball [22], volleyball [23], swimming [24], scuba diving [25-30], dancing [31,32], yoga [33], vigorous exercise [33], trampoline use [34], roller coaster or amusement park rides [35-40], and minor sports injuries [41,42]. Other reported precipitating activities include childbirth [43], sexual intercourse [44], and coughing or sneezing [33]. Chiropractic neck manipulation may trigger dissection [45-50], but causality is difficult to establish, and the absolute incidence of dissection caused by spinal manipulation is unknown [50-53].

Associated conditions — The proportion of patients with spontaneous cervical artery dissection who are affected by a known connective tissue or vascular disorder is low [54-57]. Nevertheless, various connective tissue and vascular disorders have been associated with dissection, including the following [16,58,59]:

â—ŹFibromuscular dysplasia [60-63]

â—ŹEhlers-Danlos syndrome type IV (vascular Ehlers-Danlos)

â—ŹMarfan syndrome

â—ŹOsteogenesis imperfecta [64]

â—ŹCystic medial necrosis [65]

â—ŹReticular fiber deficiency [66]

â—ŹHomocystinuria [67]

â—ŹAutosomal dominant polycystic kidney disease [68]

â—ŹAlpha-1 antitrypsin deficiency [69]

â—ŹSegmental mediolytic arteriopathy [70]

â—ŹReversible cerebral vasoconstriction syndromes [71]

â—ŹCervical artery tortuosity [72]


The most common association is with fibromuscular dysplasia, a nonspecific arteriopathy, which accounts for 15 to 20 percent of all cases of cervicocephalic dissection [62,73]. Ehlers-Danlos syndrome type IV is found in <2 percent of all cases of cervical or cerebral artery dissection [54,55]. The prevalence of dissection among all patients with Ehlers-Danlos is similarly infrequent. In one cohort of over 400 patients with Ehlers Danlos type IV, carotid artery dissection was observed in 2 percent [74].

For the remaining connective tissue and vascular disorders listed above, all of which are rare diseases, it remains uncertain whether the association with dissection is greater than would be expected by chance alone [59]. As an example, a series of 1934 patients with cervical artery dissection identified only 6 (<1 percent) with an inherited connective tissue disease [56]. There were two patients with genetically confirmed vascular Ehlers-Danlos and one patient each, diagnosed by clinical criteria, with Marfan syndrome, classic Ehlers-Danlos, hypermobile Ehlers-Danlos, and osteogenesis imperfecta. Although Marfan syndrome is a known cause of aortic dissection, only a few cases of isolated cervicocephalic dissection have been reported in patients with Marfan syndrome [75,76], and several large series of patients with Marfan syndrome have reported no occurrences of cervicocephalic dissection [77,78].

In contrast to the rare association of connective tissue disease with cervicocephalic artery dissection, one case-control study found that patients with spontaneous cervical artery dissection (n = 84) compared with matched control patients who had ischemic stroke without dissection (n = 84) were significantly more likely to have clinical signs suggestive of connective tissue abnormalities [57]. These signs involved mainly skeletal (eg, scoliosis, pectus excavatum), skin (eg, mild skin hyperextension), and ocular abnormalities as well as craniofacial dysmorphisms. However, none of the patients with cervical artery dissection had an established hereditary connective tissue disease.

Based upon relatively weak supporting evidence, a host of other conditions have been associated with cervicocephalic dissection, including recent infection, hypertension, migraine, longer styloid process length, aortic root diameter >34 mm, oral contraceptive use, smoking, elevated homocysteine levels, alcohol use, redundancy of vessels, higher body height, and lower body weight [59,79-91]. Dissections have been noted in association with other vascular findings such as cerebral aneurysms and arterial fenestrations [92].

Genetics — In addition to the monogenic connective tissue diseases discussed above, polygenetic factors may be involved in the etiology and pathophysiology of dissection as part a multifactorial predisposition [54]. In theory, such factors could cause an inherited weakness of the vessel wall, thereby increasing susceptibility to dissection from minor trauma, inflammation, thrombosis, or other environmental triggers.

However, there are no established genetic markers for cervicocephalic dissection. A genome-wide association study suggested that the rs9349379[G] allele of the PHACTR1 gene was associated with a lower risk of cervical artery dissection [93], but further confirmation is needed. An earlier systematic review published in 2009 noted that the majority of genetic studies in this field were negative, and were also markedly underpowered [54]. The following additional observations were made:

â—ŹAutosomal dominant Ehlers-Danlos syndrome type IV caused by a mutation in the COL3A1 gene probably accounts for <2 percent of all cervical artery dissection cases

â—ŹWith Marfan syndrome, an autosomal dominant condition caused by a mutation in the fibrillin 1 gene, spontaneous cervical artery dissection appears to be exceptional, and should be distinguished from aortic dissection that extends in the brachiocephalic arteries.

â—ŹAmong 15 genetic association studies, 10 were negative while 5 reported associations with three genetic variants in three different candidate genes (ICAM-1, COL3A1 and MTHFR C677T genotype). A meta-analysis of these reports found a significant association only for the MTHFR C677T genotype (odds ratio 1.67, 95% CI 1.21-2.31).

â—ŹAmong nine genetic screening studies and four linkage studies, most results were negative.


Despite the paucity of evidence, there are valid reasons to suspect that genetic factors are related to the pathophysiology of cervicocephalic dissection. As an example, patients with a family history of arterial dissections involving cervicocephalic arteries, renal arteries or the aorta appear to be at increased risk for recurrent arterial dissection [94,95]. Furthermore, patients with apparently sporadic cervicocephalic artery dissection have a high prevalence of ultrastructural connective tissue abnormalities (see 'Pathology' above) that are not associated with any defined collagen vascular disease. In some families, these connective tissue alterations appear to be transmitted in an autosomal dominant pattern [96,97].

EPIDEMIOLOGY — Spontaneous dissection is a common cause of stroke, particularly in young adults (see "Ischemic stroke in children and young adults: Etiology and clinical features", section on 'Dissection'), where it accounts for approximately 20 percent of ischemic stroke. A population-based study from Minnesota reported that the average annual incidence rate for spontaneous internal carotid artery dissection was 1.72 per 100,000 individuals, while that for spontaneous vertebral artery dissection was 0.97 per 100,000; the combined annual incidence of spontaneous dissection was 2.6 per 100,000 [9]. The true incidence is probably even higher, since many cases of dissection may escape detection because they have minor or no clinical signs [59]. In studies from North America and Europe, the mean age of individuals affected by dissection was 44 to 46 years [9-11]. There is no clear gender or ethnic predilection, although some studies have shown a slight predominance for men or women [9-11,59,98,99]. Dissection may be more common in winter, although the cause of seasonal variation remains unclear [100].

Extracranial dissection is far more frequent than intracranial dissection in reports from North America and Europe. However, evidence from several case series suggests that intracranial dissection is more common in Asian populations and in children [101,102].

CLINICAL FEATURES — Evidence from population- and hospital-based reports suggests that dissection most often results in ischemic stroke or transient ischemic attack, usually associated with local symptoms such as neck pain or headache [9-11,103]. However, these studies may underestimate the proportion of cases that are asymptomatic or associated with local symptoms only [59]. For patients without ischemia at the time of diagnosis, retrospective data suggest that the risk of ischemic stroke is limited to the first two weeks after the diagnosis of cervical artery dissection [104].

Local symptoms — The most frequent initial symptom of cervicocephalic dissection is head and/or neck pain, found in 60 to 90 percent of cases [9,103,105-107]. Although the onset of headache is usually gradual, a sudden and severe onset of pain consistent with a thunderclap headache occurs in up to 20 percent of patients with headache due to dissection (table 1) [108]. (See "Approach to the patient with thunderclap headache".)

Horner syndrome (figure 3) occurs in approximately 25 percent of cases [9], and is due most often to distension of sympathetic fibers spanning the external surface of the internal carotid artery. The Horner syndrome seen with internal carotid artery dissection is usually partial, involving ptosis and miosis but not anhidrosis. This occurs because the sympathetic fibers responsible for facial sweating and vasodilation branch off at the superior cervical ganglion from the remainder of the oculosympathetic pathway and travel with the external carotid artery. (See "Horner syndrome".)

Other manifestations of dissection may include tinnitus [109], an audible bruit, cranial neuropathies (figure 4) [5,110], or scalp tenderness. Cervical nerve root involvement is a rare complication of vertebral artery dissection [111,112], while isolated orbital or monocular pain is a rare presentation of carotid artery dissection [113,114].

Ischemia — In a population-based report of 48 patients with spontaneous dissection of the internal carotid and vertebral arteries, cerebral ischemia was noted in 67 percent, with transient ischemic attacks and cerebral infarction in 23 and 56 percent, respectively [9]. Retinal artery occlusion or ischemic optic neuropathy may also occur [10,115,116].

Vertebral dissection may lead to lateral medullary infarction (Wallenberg syndrome), other posterior circulation territory infarction, or spinal cord ischemia [111].

Subarachnoid hemorrhage — Intracranial artery dissection may result in subarachnoid hemorrhage. In a 2015 systematic review of retrospective case series, subarachnoid hemorrhage was associated with intracranial artery dissection in 8 to 69 percent of cases [102].

Internal carotid versus vertebral dissection — Aside from obvious differences in neurologic symptoms and signs related to their different territories, carotid and vertebral dissections may differ in risk factors, other clinical features, and outcome. One of the largest observational studies evaluating these characteristics (the CADISP study) included 982 patients with cervical artery dissection, and excluded those with purely intracranial dissection [103]. The following statistically significant observations were reported:

â—ŹMean age was slightly higher for patients with internal carotid artery dissection compared with vertebral artery dissection (46 versus 41 years)

â—ŹThe proportion of men was higher for internal carotid dissection (60 versus 51 percent)

â—ŹInfection in the previous week was more common with internal carotid dissection (22 versus 15 percent)

â—ŹMinor cervical trauma in the previous month was more frequent with vertebral dissection (37 versus 29 percent)

â—ŹNeck pain was more frequent with vertebral dissection (66 versus 39 percent)

â—ŹIschemic stroke was more common with vertebral dissection (77 versus 60 percent)

â—ŹTransient monocular blindness occurred only with internal carotid dissection (8 versus 0 percent)

â—ŹThe mean National Institutes of Health Stroke Scale score at presentation among those with stroke was higher with internal carotid dissection (8 versus 3)

â—ŹBilateral dissection was more frequent with vertebral dissection (16 versus 10 percent)

â—ŹAneurysmal dilatation was more common with internal carotid dissection (14 versus 8 percent)

Of note, there were no significant differences between internal carotid and vertebral dissection for the occurrence of headache (68 and 65 percent), transient ischemic attack not including transient monocular blindness (20 versus 21 percent), arterial occlusion (34 versus 33 percent), or mural hematoma (83 versus 78 percent) [103].

DIAGNOSIS — While clinical features may raise suspicion for dissection, the diagnosis is confirmed by neuroimaging findings (see 'Neuroimaging' below), particularly the demonstration of a long tapered arterial stenosis, a tapered occlusion, a dissecting aneurysm (pseudoaneurysm), an intimal flap, a double lumen, or an intramural hematoma. Headache or neck pain at onset may suggest underlying dissection, especially as a cause of stroke in the young. The acute onset of Horner syndrome in association with neck pain and an ischemic stroke or transient ischemic attack in the territory of the ipsilateral internal carotid artery is suggestive of spontaneous carotid artery dissection [59]. However, patients age ≥60 years with cervical artery dissection may be less likely to present with neck pain, headache, preceding trauma, or a mechanical triggering event [117]. Therefore, the possibility of dissection should not be disregarded when these features are absent in older individuals with unexplained TIA or acute ischemic stroke. We suggest lumbar puncture and cerebrospinal fluid analysis to exclude subarachnoid hemorrhage for patients with suspected dissection who have severe or sudden onset headache, and for patients who have intracranial dissection or intracranial extension of extracranial dissection, particularly if treatment with anticoagulation is being considered [118].

As noted previously (see 'Associated conditions' above), the proportion of patients with spontaneous dissection who are affected by a known connective tissue or vascular disorder is low. Therefore, we generally do not pursue additional testing for such disorders unless there is heightened clinical suspicion because of suggestive symptoms, signs or family history (eg, joint hypermobility, multiple joint dislocations, translucent skin, poor wound healing, easy bruising, and unusual scars consistent with Ehlers-Danlos syndrome). (See "Clinical manifestations and diagnosis of Ehlers-Danlos syndromes".)

The diagnosis of fibromuscular dysplasia (FMD) is made from angiography, so typically no additional testing is needed if extracranial arteries show no signs of FMD on magnetic resonance angiography (MRA) or computed tomography angiography (CTA). An exception might be patients with clinical manifestations suggestive of renal FMD, where evaluation of renal arteries could prove diagnostic. (See "Clinical manifestations and diagnosis of fibromuscular dysplasia".)

Neuroimaging — Vascular imaging is used to confirm an initial diagnosis of cervicocephalic dissection and to guide serial treatment decisions. In most centers, conventional angiography has been supplanted by noninvasive approaches, particularly brain MRI with MRA and cranial CT with CTA [119-121]. A systematic review published in 2009 found that the sensitivity and specificity of MR techniques and CTA for the diagnosis of cervicocephalic arterial dissection are relatively similar [119]. We reserve the use of conventional angiography for younger patients when clinical suspicion for dissection remains high despite negative noninvasive imaging. There is no need for conventional angiography if the diagnosis of cerebral or cervical artery dissection is clear using CTA or MRA.

Angiographic findings of dissection include a string sign (image 1), tapered stenosis or occlusion or flame-shaped occlusion (image 2), intimal flap (image 3), dissecting aneurysm (image 4), distal pouch, and underlying arteriopathy. Multimodal CT or MRI, including CTA or MRA, may illustrate luminal abnormalities, arterial wall expansion, intramural hematoma, and surrounding structures. In a population-based study of 48 consecutive patients with cervical artery dissection, the diagnostic neuroimaging patterns were an elongated tapered stenosis, a tapered occlusion, and a dissecting aneurysm in 48, 35, and 17 percent, respectively [9]. In a prospective European study of patients with spontaneous vertebral artery dissection, the most frequent diagnostic neuroimaging finding on MRI was intramural hematoma, which was observed in 91 percent of 157 vertebral artery dissections.

Extracranial carotid dissections typically occur 2 cm or more beyond the carotid bifurcation, near or adjacent to the level of the skull base [7]. Intracranial carotid dissections are most frequent in the supraclinoid segment [8]. Vertebral artery dissection most often occurs in the cervical transverse processes of C6 to C2 (V2 segment) or the extracranial segment between the transverse process of C2 and the foramen magnum at the base of the skull (V3 segment) [118].

The pathognomonic crescent sign of intramural hematoma is formed by an eccentric rim of hyperintensity surrounding a hypointense arterial lumen on MRI (image 5). This crescent sign has traditionally been described on T1-weighted fat-saturation MRI sequences, but may be apparent on other sequences such as diffusion-weighted imaging [122] or even apparent on CT angiography. The degree of MRI hyperintensity and the methemoglobin content of the intramural hematoma varies with age of the lesion. Dissections of the horizontal vertebral artery segment may be difficult to diagnose as the classic crescent may be missing due to orientation of the vessel and the vertebral venous plexus may also appear hyperintense. The orientation of the vertebral artery may also limit delineation of a crescent, as the lumen may be patent yet surrounded by a more irregular "suboccipital rind" sign [123]. Assessment of multimodal CT or MRI source images is crucial to define vessel wall abnormalities.

Carotid duplex and transcranial Doppler ultrasonography (TCD) may be used to screen for suspected dissection, or to monitor therapy [124-127]. However, carotid duplex detects abnormalities in only 68 to 95 percent of cases [124,128]. In addition, duplex and transcranial Doppler have a suboptimal yield for identifying arterial dissection near the skull base and vertebral artery dissection within the transverse foramina [59,121]. In addition, ultrasound is unreliable for detecting carotid artery dissection in patients with an isolated Horner syndrome [129]. Therefore, confirmation with MRA or CTA should be pursued in ultrasound-negative cases when the clinical history is suggestive of dissection [130].

The pattern of brain ischemia on diffusion-weighted MRI may be influenced by the patency of the dissected artery, with territorial rather than borderzone infarcts apparent when there is complete occlusion of the vessel [131]. The advent of high-resolution 3 Tesla MRI has made it possible to detail interval recanalization, degree of stenosis, formation of dissecting aneurysms and the appearance of new dissections as part of serial imaging evaluations [132]. Periarterial inflammation associated with dissection may also be visualized with such high-resolution MRI techniques [133].

Differential diagnosis — The differential diagnosis of cervicocephalic dissection is broad, given that the manifestations may include local symptoms (primarily head and neck pain, Horner syndrome, lower cranial nerve palsy), brain ischemia, or subarachnoid hemorrhage, either in isolation or in combination. (See 'Clinical features' above.)

Entities to be considered in the differential diagnosis of head and neck pain include various types of headache, particularly those with unilateral head pain and those accompanied by autonomic symptoms such as ptosis and miosis. The list includes migraine, cluster headache and other trigeminal autonomic cephalalgias (eg, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing [SUNCT] syndrome), and Raeder paratrigeminal neuralgia [106]. Migraine should be suspected when there is a characteristic march of transient neurological deficits, although this pattern has been reported as well in rare patients with internal carotid artery dissection [134]. Cluster headache typically occurs without focal deficits. (See "Pathophysiology, clinical manifestations, and diagnosis of migraine in adults" and "Pathophysiology, clinical features, and diagnosis of migraine in children" and "Cluster headache: Epidemiology, clinical features, and diagnosis" and "Paroxysmal hemicrania: Clinical features and diagnosis" and "Overview of craniofacial pain", section on 'Paratrigeminal oculosympathetic syndrome'.)

Thunderclap headache, a severe headache of sudden onset, occurs in a minority of patients with cervicocephalic dissection. In addition, thunderclap headache is characteristic of the pain associated with the onset of subarachnoid hemorrhage and can be associated with multiple other causes as listed in the table (table 1). (See "Approach to the patient with thunderclap headache".)

The differential diagnosis of brain ischemia includes cardiogenic embolism, large artery atherosclerosis, small vessel disease, and a host of less common mechanisms such as a vasculopathy other than spontaneous dissection. Intracranial vertebral artery occlusive disease due to atherosclerosis is a more common cause of lateral medullary ischemia than is vertebral dissection. (See "Differential diagnosis of transient ischemic attack and stroke" and "Etiology, classification, and epidemiology of stroke" and "Ischemic stroke in children and young adults: Etiology and clinical features" and "Posterior circulation cerebrovascular syndromes", section on 'Lateral medullary infarction'.)

The differential diagnosis of subarachnoid hemorrhage includes saccular aneurysm rupture, bleeding from a vascular malformation, perimesencephalic nonaneurysmal subarachnoid hemorrhage, and a number of less common causes. (See "Clinical manifestations and diagnosis of aneurysmal subarachnoid hemorrhage" and "Nonaneurysmal subarachnoid hemorrhage" and "Perimesencephalic nonaneurysmal subarachnoid hemorrhage".)

Angiographic features of dissection must be distinguished from atherosclerosis, radiation arteriopathy, and congenital hypoplasia of an artery. All of these conditions may produce an angiographic "string sign" that is commonly seen with dissection. The luminal contour of narrowing caused by dissection may be similar to atherosclerosis, fibromuscular dysplasia, vascular webs, stationary waves, and arteritis.

TREATMENT — The treatment and prognosis of cervicocephalic dissection is reviewed in detail separately. (See "Spontaneous cerebral and cervical artery dissection: Treatment and prognosis".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Stroke in adults" and "Society guideline links: Stroke in children".)

SUMMARY AND RECOMMENDATIONS

â—ŹSeparation of the arterial wall layers results in dissection. A false lumen arises in the space where blood seeps into the vessel wall (figure 1). Hemorrhage may be due to an intimal tear or result from rupture or other pathology in the vasa vasorum. Subintimal dissections cause luminal stenosis or occlusion whereas subadventitial dissections largely result in dissecting aneurysm formation (figure 2). (See 'Pathophysiology' above.)

â—ŹDissection may result from a combination of intrinsic deficiencies of vessel wall integrity and extrinsic factors, including minor trauma. Numerous proposed risk factors and inciting activities have been associated with dissection. (See 'Etiology' above.)

â—ŹSpontaneous dissection of the cervical and cerebral arteries occurs in about 3 cases per 100,000 individuals across all ages, yet accounts for up to one quarter of all stroke cases in the young. (See 'Epidemiology' above.)

â—ŹEvidence from population and hospital-based reports suggests that dissection most often results ischemic stroke or transient ischemic attack, usually preceded by local symptoms such as neck pain or headache. However, these studies may underestimate the proportion of cases that are asymptomatic or associated with local symptoms only. Uncommonly, intracranial dissection results in subarachnoid hemorrhage. (See 'Clinical features' above.)

â—ŹThe diagnosis of cervicocephalic dissection is confirmed by neuroimaging findings, particularly the demonstration of a long tapered arterial stenosis, a tapered occlusion, a dissecting aneurysm (pseudoaneurysm), an intimal flap, a double lumen, or an intramural hematoma. Various neuroimaging modalities may be used to confirm a diagnosis of dissection. In most centers, conventional angiography has been supplanted by brain MRI with magnetic resonance angiography or by cranial CT with computed tomography angiography. (See 'Diagnosis' above.)

â—ŹThe treatment and prognosis of cervicocephalic dissection is reviewed in detail separately. (See "Spontaneous cerebral and cervical artery dissection: Treatment and prognosis".)



Here is some information from across the pond:

http://journals.sagepub.com/...177/2396987317720544

Good luck.
Dale
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