Bilateral transient perivascular inflammation of the carotid artery (TIPIC) syndrome

A 52-year-old female patient presented to ER complaining of right-neck pain, extending to the ipsilateral mandible. Clinical examination revealed sensitivity of the right-cervical region, with no obvious mass. Patient had a history of surgically removed breast tumour. Laboratory tests showed an elevated C-reactive protein and erythrocyte sedimentation rate.

Doppler ultrasonography showed hypoechoic, with scattered hyperechoic foci, asymmetric, perivascular soft-tissue (0.38 cm maximum thickness), of the right-carotid bulb, the proximal portion of the right-internal carotid artery (RICA) and distal part of the right-common carotid artery (RCCA) (Figs. 1 a, b, c).
Same findings, but in less extent, in the contralateral carotid artery.
Axial T1-weighted high resolution isotropic volume (THRIVE), T1-weighted post Gd and STIR MRI images, verified the absence of mural hematoma and the concentric enhancement of the wall, a sign of pericarotid inflammation (Figs. 2a, b, c).
Follow-up MRI images, of the same sequences, two months later, showed decreased signal and thickness of the abnormal tissue, due to fibrosis (Figs. 3 a,b,c).

Background:
Idiopathic carotidynia (IC) is a clinical entity described by Fay in 1927, characterised by tenderness and pain at the level of the carotid bifurcation without structural abnormality. It was classified as an idiopathic neck pain syndrome in the first international classification of headache disorders in 1988. Since recently, this entity is called “transient perivascular inflammation of the carotid artery (TIPIC) syndrome”. Most cases are unilateral; however, about 10% of cases are bilateral [1,2].

Clinical perspective:
Most studies hypothesise that the perivascular changes are consistent with inflammation. Biopsy specimens revealed nonspecific chronic inflammation with proliferation of fibroblasts, lymphocytes, mastocytes, and eosinophils, without granuloma formation or evidence of active infection and proliferation of small vessels. These inflammatory changes were distinct from histologic findings in large vessels involved by vasculitis, and no giant cells were present at histopathology. Based on the above, it was suggested that IC represents a distinct form of carotid/pericarotid inflammation [3,4].
Clinical findings support this hypothesis, with ipsilateral lymph node enlargement, as well as an increase of the erythrocyte sedimentation rate or C-reactive protein. It is a clinical phenomenon that almost always evolves with self-limiting symptoms. [1,3,5]

Imaging perspective:  
Ultrasonography (US) can detect perivascular tissue with high accuracy, similar to other imaging methods. Follow-up could be made with US too, to assess the decrease in size of the perivascular tissue.
MRI shows the most characteristic findings, with a better characterisation of the eccentric wall-thickening of CCA, when there is hypointense signal on T1 and hyperintense signal on T2, associated with regional contrast-enhancement of the tissue, indicating inflammation. Carotid dissection can be ruled out at MRI, due to the absence of a T1-hyperintense wall haematoma. In large vessel arteritis, the thickened arterial wall enhances intensively on MRI and is generally associated with luminal stenosis and is not limited to the carotid bifurcation [2].

Outcome:
A common treatment is NSAIDS and corticosteroids. Most patients have complete clinical resolution with laboratory markers of inflammation returning to normal but may present with ≥1 relapses, with intervals ranging from 1 to 6 months [1].

Take-Home Message-Teaching Points:
● Clinicians should think about the TIPIC syndrome in the differential diagnosis of neck pain.
● Ultrasound evaluation is crucial in the diagnosis (to exclude other entities in the differential diagnosis) and in the follow-up evaluation of treatment.
● Recognition of this syndrome is cost-effective and can help us avoid unnecessary, additional diagnostic examinations.
Written informed patient consent for publication has been obtained.