The difference in blood pressure readings between arms and survival: primary care cohort study

Difference in blood pressure between two arms: don’t forget vasculitis

I read with interest the article by Clark et al [1] and the related editorial [2]. However, the authors do not cite large vessel vasculitis as an important and readily treatable differential diagnosis when a discrepancy in blood pressure recordings between limbs is observed. For example, Takayasu arteritis (TA) is a rare granulomatous large vessel vasculitis and a difference in systolic blood pressure between arms of greater than 10mmHg is included in the 1990 American College of Rheumatology classification criteria [3].

Another very important clinical sign in TA is a reduction in volume or absence of peripheral arterial pulses, particularly the brachial. This is a common finding in these patients the importance of which, together with blood pressure discrepancy, can be overlooked both in primary and secondary care, often leading to a delay in diagnosis in a condition associated with considerable morbidity and mortality if left untreated.

Giant cell arteritis (GCA) is a considerably more common and well recognised form of large vessel vasculitis and may also cause a discrepancy in blood pressure between limbs and a reduction or absence in peripheral pulses. GCA and TA should therefore be considered in any patient found to have a significant difference in blood pressure between arms, particularly in the context of relevant constitutional symptoms, limb claudication and other ischaemic symptoms, or an unexplained persistent elevation in ESR and CRP.

1. Clark CE, Taylor RS, Shore AC, Campbell JL. The difference in blood pressure readings between arms and survival: primary care cohort study. BMJ 2012; 344: 19

2. Kim DH. Differences in blood pressure between arms. BMJ 2012; 344: 9

3. The American College of Rheumatology 1990 criteria for the classification of Takayasu arteritis. Arend WP, Michel BA, Bloch DA, Hunder GG, Calabrese LH, Edworthy SM, Fauci AS, Leavitt RY, Lie JT, Lightfoot RW Jr et al. Arthritis Rheum 1990 33: 1129-34