Carotidynia.

A 46-year-old female presented with significant pain in the right side of the neck of 1 month duration. Point tenderness was elicited on palpation without a noticeable swelling. She was referred for an ultrasound of the neck which was reported as normal. In view of persistent pain and at the insistence of the patient, she was referred for a magnetic resonance imaging (MRI). A fiducial marker was placed at the site of maximum pain and tenderness.

MRI showed abnormal enhancing eccentric soft tissue at the posterolateral wall of the right carotid bulb and internal carotid artery (ICA) origin close to the bifurcation [Figure 1]. It caused mild indentation on the adjacent carotid artery lumen.

Figure 1

Index MRI. Axial postcontrast T1-weighted image of the neck shows eccentric enhancing perivascular soft tissue (arrows) in relation to the right carotid bulb

Correlating this radiological finding with the clinical presentation of pain; a diagnosis of transient perivascular inflammation of the carotid artery (TIPIC) or carotidynia was made. Erythrocyte sedimentation rate (ESR) (55 mm/h) and C-reactive protein (CRP) (25 mg/dL) were elevated. Resolution of symptoms on anti-inflammatory medication validated the diagnosis. At 6 months, follow-up MRI showed significant regression of perivascular inflammatory soft tissue [Figure 2]. At 6 months follow-up on anti-inflammatory medication, ESR and CRP normalized.

Figure 2

6 months follow-up MRI. Axial postcontrast T1-weighted image of the neck shows significant regression of eccentric enhancing perivascular soft tissue (arrows) in relation to the right carotid bulb

A differential diagnosis of acute onset neck pain includes vascular etiologies such as vessel wall dissection and vasculitis and nonvascular entities including head and neck inflammation, sialadenitis and cervical spine degeneration. An overlooked clinicoradiological vascular etiology of acute cervical pain is carotidynia; recently described by the self-explanatory acronym TIPIC.[1]

Although a rare entity, the clinicoradiological presentation of TIPIC is classic and consistent. Patients have distinctive acute pain directly at the level of the carotid bifurcation with eccentric perivascular inflammatory (PVI) soft tissue on imaging as the most striking feature described. Some patients have mild associated narrowing of the lumen without hemodynamic abnormality.

Prior case reports theorized that the perivascular changes represent inflammation.[23] Excellent response to anti-inflammatory medication, occasional reports of ipsilateral lymph node enlargement and/or bordering pharyngolaryngeal inflammation and mild elevation of inflammatory markers like ESR and CRP support this conjecture.

Lecler et al. suggested this entity should be added to the International Classification of Headache Disorders-III and proposed four major diagnostic criteria which included acute pain overlying the carotid artery, eccentric PVI on imaging, exclusion of alternative vascular or nonvascular diagnosis with imaging and finally; improvement within 2 weeks which is either spontaneous or as a response to anti-inflammatory treatment.[45]

Knowledge and diagnosis of this uncommon but consistent clinicoradiological entity is constructive; as it responds well to medical treatment with nonsteroidal anti-inflammatory agents and high doses of aspirin. The condition is known to be self-limiting. Misdiagnosis as dissection or atherosclerosis is common and unfortunate as it can potentially trigger a regrettable cascade of anxiety and unnecessary further investigations.

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