Carotid Artery Dissection, Neck Pain, and Horner’s Syndrome

carotid artery dissection and neck pain and horner's syndromeThe majority of acute onset neck pain is due to muscle tension but in some cases left-sided neck pain, right-sided neck pain, or neck pain that presents with Horner’s syndrome are the result of carotid artery dissection or carotidynia. It appears that carotid artery dissection, whilst once thought fairly rare, is actually a risk for many people, young or old, active or inactive. Indeed, activities such as running, golf, and contact sports can all lead to acute trauma to the carotid artery and neck pain, and for some patients this can be fatal. In today’s blog post we take a look at a case of Horner’s syndrome as a result of carotid artery dissection.

Carotid Artery Dissection Leading to Horner’s Syndrome

This case of carotid artery dissection occurred in an active 25 year old woman after running 10km on a treadmill. Her first symptom was mild left-sided neck pain shortly after finishing her run. A few hours later the woman noticed her left pupil was constricted and her eyelid had begun to droop. She sought the help of an ophthalmologist who diagnosed Horner’s syndrome as a result of viral infection. The woman ran again the next day and noticed that the left half of her forehead did not sweat so, clearly concerned, she went to the hospital for further assessment.

Diagnosing Horner’s Syndrome

Diagnostic imaging found no abnormalities in her carotid arteries on ultrasound but a magnetic resonance angiogram did find a dissection of her extracranial internal carotid artery. As there was no evidence of blood clots at the time, the woman was treated with aspirin as an anticoagulant and the carotid artery dissection had repaired itself by the time of follow-up six months later. The Horner’s syndrome has, however, remained. The woman had no underlying condition predisposing her to carotid artery dissection and is an example of how fairly minor trauma to the neck can cause the condition, even in active young people.

What is Horner’s Syndrome

Horner’s syndrome was first described in 1869, by the Swiss ophthalmologist Johann Friedrich Horner and is a result of disease, trauma, or medical intervention (idiopathic). In Horner’s syndrome there is a loss of innervation of one side of the face or head by the sympathetic nervous system, leading to ptosis (drooping) of the upper and lower eyelids, pupil constriction, anhidrosis (loss of sweating), and enophthalmos (sunken eye). Children with Horner’s syndrome may end up with one eye being much lighter than the other due to a lack of melanin production resulting from the loss of sympathetic nervous system activity in that side of the face.

Causes of Horner’s Syndrome

Carotid artery dissection was not, until recently, considered a significant cause of the syndrome but this is now thought to have been the result of poor imaging ability in many cases, leading to under-diagnosis. MRA availability has helped increase the recognition of this important cause of Horner’s syndrome and many idiopathic cases have been retrospectively attributed to carotid artery dissection. Neck pain and Horner’s syndrome can also be signs of other problems, including compression from cervical ribs, cervical spine or neck tumors, syringomyelia, thyroid cancer or goitre, or even thyrocervical venous dilatation. Those with cervical spinal stenosis may be at increased risk of carotid artery dissection and Horner’s syndrome, and certain neck pain therapies, such as chiropractic adjustment, may not be suitable due to the potential for arterial trauma.

Treating Horner’s Syndrome and Neck Pain

Anyone experiencing symptoms of Horner’s syndrome should seek medical attention immediately, especially if there has been recent neck trauma or a ‘pop’ in the neck as this could suggest carotid artery dissection. Early treatment will usually help avoid significant complications but the effects of Horner’s syndrome may remain, as in the case above, long after the resolution of neck pain and carotid artery repair.

Read more about neck cracking and popping here.


D J M Macdonald and E C A McKillop, Carotid artery dissection after treadmill running, Br J Sports Med. 2006 April; 40(4): e10.

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