The myth of carotidynia

Fay, in 1927, first used the term "carotidynia" to refer to the tenderness of the bifurcation of the carotid artery, sometimes observed in patients with "atypical facial neuralgia." He believed that the pain arose in the common carotid sheath and reported satisfactory remission of symptoms following carotid sheath resection and cervical sympathectomy. In its early description, carotidynia was a mere physical sign of tenderness, and was later referred to as the "Fay test. " However, over the years, it changed into a distinct syndrome, particularly when Roseman, in 1967, designated it as "a distinct entity" characterized by two cardinal signs: unilateral neck pain and tenderness of the carotid artery. There were hundreds of cases of carotidynia reported in the 1960s and 1970s, with two main types, acute and chronic. More recently, acute idiopathic carotidynia was accepted as a valid entity by the International Headache Society (IHS) Classification Committee with the following four diagnostic criteria: "(A) At least one of the following overlying the carotid artery: (1) tenderness, (2) swelling, (3) increased pulsations. (B) Appropriate investigations do not reveal structural abnormality. (C) Pain over the affected side of the neck. May project to the ipsilateral side of the head. (D) A self-limiting syndrome of less than 2 weeks duration."

In the last 5 years, however, carotidynia seems to have vanished almost completely from the medical literature and, in our 20-year experience with headache patients, we have never seen a case of carotidynia as defined by the IHS. It is therefore appropriate to ask, "Does carotidynia exist or does it belong to "neuromythology ?" To answer, we will discuss the validity of the four main diagnostic criteria for carotidynia proposed in the IHS classification.

Neck pain.

Carotidynia is considered by most authors to be a unilateral deep-seated neck pain radiating to the ear and face and aggravated by head movements, swallowing, chewing, coughing, yawning, and sneezing. However, many patients complain of sore throat rather than neck pain, and in some reports, neck pain was absent, replaced by pain in the face or by headache.

The pain usually recurs on the same side but may be alternating or bilateral. In one of the classic anatomic cases, the patient did not complain of any pain and had had "a bilateral painless swelling at the level of carotid bifurcation for several years." All degrees of severity have been reported, from a mild sensation of discomfort to an excruciating pain, with most of the cases being moderate or severe. The pain has been variously described as throbbing, dull, stabbing, or pulling. The pain of carotidynia, as reported in the literature, is thus highly variable in its location, type, and severity. It has no specific characteristics and no consistent pattern, and it can even be absent.

Tenderness.

Typically, the carotid artery, particularly near the bifurcation, is described as tender, swollen, and hyperpulsatile; its palpation invokes local pain and frequently reproduces the facial and head pain of the spontaneous attack. Tenderness over the course of the carotid artery was considered diagnostic in most series such as those of Roseman, with a positive Fay test in all 33 patients; of Davies, who described six patients with "extreme tenderness comparable to that of temporal arteritis" or of Raskin and Prusiner, who reported eight patients with "prominent carotid pulsations and tenderness and/or neck swelling." However, in other series, tenderness was inconstant (73 of the 100 patients reported by Lovshin and 12 of the 40 patients described by Chiossone and Quiroga) or even absent. Furthermore, tenderness in the region of the carotid artery can be present in numerous other conditions such as lymphadenitis, giant cell arteritis, aphtous ulcers, migraine, cluster headache, and carotid occlusion and dis section. Thus, the presence of tenderness over the carotid artery is neither constant nor specific and cannot be considered diagnostic of carotidynia.

Temporal profile.

There are two main patterns in the literature acute, with a single episode lasting an average of 11 days,and chronic, with years of recurrent attacks. However, on close examination of the published cases, it is impossible to define patterns of evolution. First, in some of the large classic series, the temporal profile is either not mentioned or very poorly described. Second, all varieties of temporal profiles have been reported; attacks may last minutes, hours. days, weeks, or months and their frequency is highly variable, going from a single episode to numerous episodes recurring over many years. Some patients have a "dull aching background pain episodically becoming throbbing" and others an "intractable head pain present for many years." Thus, in carotidynia, there is no typical pattern of evolution and, although a number of cases have been reported with "a self-limiting syndrome of less than 2 weeks duration" as described by the IHS classification, there are reports of many other forms, and none is more validated than the others.

Appropriate investigations.

The description of the IHS criteria for carotidynia includes the comment that "organic disease of the carotid artery may cause a similar picture and that appropriate investigations should rule out conditions such as giant cell arteritis, atherosclerosis, thrombosis, intraluminal hemorrhage, fibromuscular dysplasia, aneurysm, and aneurysmal dissection" all recognized as possible causes of carotidynia. Although it is not explicitly indicated which investigations should be performed, a proper vascular workup is crucial to rule out many of these conditions. This applies particularly to extracraniai internal carotid artery dissections, which can present as an isolated unilateral neck pain spontaneously resolving in less than 2 weeks. Such investigations include Duplex scanning, magnetic resonance imaging and angiography, and intra-arterial angiography. Furthermore, they should be performed in the first few days because of the possibility of rapid recanalization in cases of carotid dissection.

In the hundreds of published cases such vascular investigations have rarely been done, and in the few cases with carotid angiography, the carotid artery was rarely normal. Thus, in a surgical series of 10 cases (four with stroke or TIA), an arterial lesion was consistently found: carotid occlusion, atheromatous stenosis with an intraplaque hemorrhage, aneurysms (probably dissecting) with cystic medial necrosis, and fibromuscular dysplasia. Chambers et a reported seven similar cases of carotidynia with an underlying carotid artery disorder (four with stroke or TIA); two patients had a dissecting aneurysm of the internal carotid artery, two an atheromatous aneurysm of the common carotid bifurcation, two an intraluminal clot, and one a giant cell ateritis. In a series of eight cases reported by Raskin and Prusiner, carotid angiography was performed in two and was found to be normal. The first patient had a 20-year history of migraine and a 12-year history of chronic dull pain in the angle of the right jaw that improved with antimigraine drugs. The second patient also had a "chronic carotidynia" with a 4-year history of left-sided neck pain (with occasional scintillating scotomata) that disappeared with methysergide treatment. De Vries et al reported a 47 year-old woman with a 4-month history of continuous pain and tenderness of the right carotid bulb associated with dysphagia and weight loss. All investigations, including angiography, were normal. At surgery, the carotid artery was normal. The bulb was dissected and denervated with an immediate relief of symptoms. This unique case is difficult to interpret, particularly since this patient had renovascular hypertension and had been operated on for bilateral fibromuscular stenosis of renal arteries.

Proposed treatments.

Numerous treatments have been claimed to be effective in carotidynia, such as antimigraine drugs, steroids, aspirin, and surgery; this obviously suggests a wide pathogenetic heterogeneity.

A nonvalidated entity.

Thus, critical review of the relevant literature shows that carotidynia is not a validated entity. The two clinical signs on which the diagnosis is based (neck pain and tenderness) are neither constant nor specific, and there is no consistent pattern of temporal profile. What has been reported under this term in the medical literature is a potpourri of many conditions. Recurring attacks of carotidynia with headache lasting a few days are likely related to migraine, attacks lasting a few minutes suggest chronic paroxysmal hemicrania, and regular daily attacks of 1 or 2 hours duration point to cluster headache. A viral etiology has been postulated but never scientifically established in acute varieties with a self-limited course. As indicated above, carotid dissection should be ruled out in such cases. Chronic varieties with a permanent background pain probably have an important psychological component. There are reports of causes such as carotid artery diseases (occlusion fibromuscular dysplasia or giant cell or after carotid endarterectomy) but also carotid body tumors, lymphadenitis, pharyngitis, dental infection, local aphthous ulcers, or malignant infiltration.

Conclusion.

Our review indicates (as already suggested by Chambers et al that (1) idiopathic carotidynia is not a valid entity, and (2) carotidynia is simply a syndrome of a unilateral neck pain with local tenderness that can be due to numerous vascular and nonvascular causes, and therefore does not necessarily imply a carotid ongin. "Carotidynia" is a highly misleading term that should preferably be expunged from the medical nosology.