46. GCA: Diagnosed with a heavy heart

INTRODUCTION: Giant cell arteritis (GCA) represents a common cause of uncertainty for physicians. GCA can present as an indolent or aggressive process with a wide spectrum of symptoms and signs. The key to diagnosis is good clinical acumen and awareness of both common and rare associated conditions. Here we describe a rare and atypical presentation of a patient with GCA and chest pain. CASE DESCRIPTION: An 83-year old male was admitted to the medical take with 3 hours of crushing chest pain associated with diaphoresis and nausea. He had been started on 60mg prednisolone by his GP 3 days preceding this for suspected GCA (scalp tenderness, jaw claudication, polymyalgia). Past medical history included: hypertension, recent strokes (bilateral cerebellar infarcts 3 months prior), previous DVTs and COPD. Examination revealed no abnormalities. Admission ECGs showed sinus rhythm with fixed T-wave inversion in aVL and V3. Chest radiograph was normal. Bloods tests revealed mildly raised inflammatory markers (CRP, ESR 24) and a dynamic troponin (324 – 1241 – 1431 ng/L). He was diagnosed with a non-ST elevation myocardial infarction (NSTEMI) and was referred to Cardiology for an angiogram. He was started on dual antiplatelets and high dose atorvastatin. On review by Rheumatology, his recent history of bilateral posterior circulation strokes was investigated further. Multi-level bilateral vertebral artery stenosis was seen on CT angiogram at the regional hyper-acute stroke unit and diagnosed as atheromatous in origin due to: a negative right-sided temporal artery biopsy, no GCA symptoms and modest inflammatory markers (CRP in the 30s and ESR in the 20s). Due to the onset of clear and acute GCA symptoms a left-sided temporal artery biopsy and PET scan was scheduled. Prednisolone was reduced to 40mg OD due to concern over its atherogenicity during a suspected NSTEMI. Coronary angiogram went on to show clear arteries and a subsequent cardiac MRI confirmed acute myocarditis. The left temporal artery biopsy revealed chronic inflammation with scattered giant cells. The patient was diagnosed with: GCA, extra-cranial vasculitis and myocarditis. He was treated with intravenous methylprednisolone, a weaning course of prednisolone and started on methotrexate (15mg weekly). The patient’s chest pain settled soon after admission and his troponin and inflammatory markers fell with prednisolone. DISCUSSION: GCA seldom presents with myocarditis and can lead to significant morbidity and mortality. This remains an important differential in a patient with clear GCA features and chest pain. This case report adds to the growing body of evidence that myocarditis is a recognised feature of GCA. A literature review revealed 8 articles and a total of 9 patients with GCA who presented with or developed myocarditis. The initial diagnosis of an NSTEMI was reasonable in this case and the most probable cause of the patient’s symptoms, signs and blood results at the time. To this end, starting dual anti-platelets was justified. His prednisolone was reduced to 40mg due to concerns over accelerated atherosclerosis with high dose glucocorticoids in an already high-risk male with smoking history, hypertension and a stroke history. In retrospect, this was an unnecessary step, but arguably reasonable when weighing the risks and benefits of one treatment against a simultaneous acute illness (NSTEMI). Each subsequent investigation helped to diagnose and exclude certain conditions: the angiogram was necessary to exclude an acute coronary syndrome; cardiac MRI then went on to provide evidence of myocarditis; temporal artery biopsy confirmed GCA and a PET scan excluded any significant large vessel involvement. Interestingly, the first right-sided temporal artery biopsy 3 months prior was negative but the second left-sided biopsy was diagnostic. The BSR states that “contralateral biopsy is usually unnecessary”; however, a few studies have found discordant results when carrying out simultaneous bilateral biopsies with an increased diagnostic yield (Boyev et al., 1999; Breuer et al., 2009 and Durling et al., 2014), suggesting bilateral temporal artery biopsies could lead to less treatment delays and more accurate diagnoses. KEY LEARNING POINTS: Myocarditis is a recognised complication of giant cell arteritis. The key to diagnosis here was a thorough history and an open mind with regards to his background, particularly the bilateral strokes. Investigations initially did not support GCA-associated myocarditis. But the preceding typical GCA symptoms and recent strokes raised the suspicion of a more systemic vasculitis. Working off others’ diagnosis can be misleading. The very recent bilateral posterior circulation strokes and vertebral artery abnormalities were overlooked on admission due to being thoroughly worked up and disregarded as vasculitic by a tertiary stroke centre. CONFLICTS OF INTEREST: The authors have declared no conflicts of interest.