Takayasu Arteritis : A Rare Case Report with Ultrasonographic and Color Doppler Features

Takayasu arteritis is a rare form of large vessel vasculitis predominantly occurs in young females. Ultrasonography is usually the primary modality of investigation in a patient with signs and symptoms of Takayasu arteritis and features includes wall thickening, luminal narrowing or stenosis, occlusion, luminal dilatation and aneurysms and high resistance flow patterns. Suppression of inflammation and preservation of vascular competence are the aims of treatment. We present the sonographicand color Doppler findings of Takayasu arteritis in a 21 year old female.

Sonography along with color Dopplerwas done with 5-12 MHz frequency transducer which revealed long segment, diffuse, homogenous circumferential wall thickening (Figure 1, 2 and 3a) along with luminal narrowing of bilateral subclavian, common carotid, axillary, radial and ulnar arteries with high resistance flow pattern on spectral tracing (Figure 3b).Narrowing of abdominal aorta distal to the celiac axis was also noted (Figure 5).After clinical, laboratory and sonographic correlation, she was diagnosed as Takayasu arteritis and oral prednisone and methotrexate was started.On follow-up sonography there was decrease in the wall thickness of the involved vessels.

Discussion:
Takayasu arteritis is a rare inflammatory granulomatous vascular disease.Three phases has been mentioned; early prepulseless phase characterized by systemic symptoms like malaise, low-grade fever, weight loss and arthralgia.It is followed by the phase of active vascular inflammation and in advance phase, fibrotic and stenotic lesions characterize the so-called burnout disease are seen.Neurological features occurs secondary to hypertension and/or ischaemia, including postural dizziness, seizures, and amaurosis.aorta and its major branches.The most frequently involved arteries are subclavian (90%), carotid (45%), vertebral (25%) and renal (20%) arteries. 1In Takayasu arteritis, long segments of diffuse, homogeneous, circumferential vessel wall thickening are seen.This finding is more common incommon carotid artery in Takayasu arteritis and has been described as the "Macaroni sign". 6,7,14It can be distinguished from arteriosclerosis, which is more inhomogeneous. 7,8crease in wall thickness causes decreased pulsatility and loss of normal triphasic flow patternwith monophasic (Figure 4) or biphasic parvustardus type of spectral flow pattern.The diagnosis is often delayed until arterial fibrosis and stenosis occurs. 13The radiographic findings are a result of adventitial thickening, inflammation and cellular infiltration of the tunica media and intimal hyperplasia. 14Aneurysm formation occurs due to significant destruction of the tunica media.There is long segment luminal stenosis or narrowing as compared with atherosclerosis or fibromuscular dysplasia, in which the stenoses are usually short segments.Calcification is more commonly seen in atherosclerosis.Lumen occlusion is found in the advance phase.Due to chronicity and slow progression of the disease, occlusions are commonly associated with collateral flow. 8mplications in Takayasu arteritis are retinopathy, secondary hypertension, aortic regurgitation, and aneurysm formation. 5The pulmonary trunk is found to be more commonly involved compared with the intrapulmonary arteries. 9[13] Steroid and methotrexate therapy are the main medical treatment for Takayasu arteritis; however mycophenolatemofetil may be useful.Surgery is indicated in severe renal artery stenosis, extremity claudication limiting daily activities, cerebrovascular ischaemia, moderate aortic regurgitation and cardiac ischaemia.Takayasu arteritis is a systemic vasculopathy that can progress to cause vital organ ischaemia, hence long term follow up is recommended.

Conclusion:
Sonography is often the primary modality of investigation in a patient with signs and symptoms of Takayasu arteritis.Sonography in conjunction with color Doppler scanning is a valuable tool for accurate diagnosis, grading, follow-up and response to treatment.
Sonographic signs include wall thickening, luminal narrowing or stenosis, luminal occlusion, luminal dilatation and aneurysms,calcification and high resistance signals in typically low resistance vascular beds.Wall thickening is the earliest finding with frequent involvement of arch of

Fig
Fig.-3a and 3b:Transverse and longitudinal sonographic images(Figure 3a) showing diffuse wall thickening and luminal narrowing of right brachial artery with high velocity flow on color Doppler (Figure 3b).

Fig.- 4 :
Fig.-4:Doppler sonographicimage showing loss of triphasicity with monophasic low flow pattern in the left ulnar artery due to proximal brachial artery narrowing.