Polymyalgia Rheumatica and Giant Cell Arteritis

Chapter 17
Polymyalgia Rheumatica and Giant Cell Arteritis

Christian D. Mallen¹ and Eric L. Matteson²

¹ Institute for Primary Care and Health Sciences, NIHR Research Professor in General Practice, NIHR CLAHRC West Midlands; NIHR School for Primary Care Research Training Lead, Honorary Professor in Rheumatology, University of Birmingham; Keele University, Keele, UK

² Division of Rheumatology, Department of Internal Medicine and Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, USA

Polymyalgia rheumatica (PMR) is characterized by bilateral pain and stiffness of the hips and shoulders, typically associated with elevated inflammatory markers. This highly disabling condition is the most common inflammatory rheumatological disorder of older people. Whilst most patients with PMR are exclusively managed in the community, diagnosis and management can be challenging, especially for those with an atypical presentation and those not responding classically to glucocorticoid treatment.

Giant cell arteritis (GCA) is a systemic vasculitis that frequently co‐occurs with PMR. Whilst it may affect any large or medium‐sized artery, it has a propensity to affect the branches of the external carotid artery, particularly the posterior ciliary arteries that supply the optic nerve and the superficial temporal artery (hence the use of the alternative name temporal arteritis). Prompt recognition and early treatment are essential to prevent long‐term complications, including permanent loss of vision.

There are clinical and pathogenetic links between temporal arteritis, giant cell arteritis and polymyalgia rheumatica, which has led to the concept that they are manifestations of a disease spectrum that affects the same disease population. The two entities may occur in the same patient simultaneously, at different time points or independently. Polymyalgia rheumatica has been observed in 40–60% of cases of giant cell arteritis, and 30–80% of patients with polymyalgia rheumatica have giant cell arteritis.

Epidemiology

Both PMR and GCA affect similar patient populations. Both conditions are rare below the age of 50 and peak in patients aged over 70 years. Women are affected three times more frequently than men, and whilst it can affect any ethnic group, it is more common in northern Europeans. The age‐adjusted incidence rate is around 8.4 per 10 000 person‐years for PMR and 2.2 per 10 000 person‐years for GCA (Smeeth et al., 2006). The lifetime risk of PMR is higher for women (2.4%) than for men (1.7%), as is the lifetime risk of GCA (1.0% for women and 0.5% for men) (Crowson et al., 2011). Co‐occurrence is common, with 3.8% of PMR patients having GCA previously and 8.2% of GCA patients having PMR previously.

Clinical features and diagnosis

Making a diagnosis of PMR can be challenging, especially given the absence of a ‘gold standard’ diagnostic test. Symptom onset is often rapid and dramatic, with bilateral pain and stiffness in the shoulders and hips causing marked functional impairment. Patients often report problems lifting heavy objects, getting off the toilet or rolling over in bed. Inflammatory markers (erythrocyte sedimentation rate (ESR) and C‐reactive protein (CRP)) are usually elevated and patients may complain of systemic features including fatigue, weight loss, flu‐like symptoms and depression. Atypical presentation may lead to diagnostic difficulty, and as such early referral for specialist assessment can be helpful in non‐classic cases.

A wide range of rheumatological and non‐rheumatological disorders mimic PMR (Table 17.1), making a careful clinical assessment essential to improve the accuracy of the diagnosis. The publication of provisional classification criteria, whilst not intended for diagnostic use (Table 17.2), usefully describes the core features of PMR (Dasgupta et al., 2012).

Table 17.1 Differential diagnosis of PMR and GCA

Category	Example
Inflammatory rheumatological disorders	Rheumatoid arthritis Giant cell arteritis Spondyloarthropathy Crystal arthropathy
Non‐inflammatory rheumatological disorders	Osteoarthritis Shoulder pathology (e.g. frozen shoulder, rotator cuff disease) Fibromyalgia
Infection	Bacterial endocarditis, osteomyelitis septic arthritis, tuberculosis and other infections
Malignancy	Leukaemia, lymphoma, myeloma Solid tumours (including prostate, renal, lung)
Endocrine	Diabetes Hypo/hyperthyroidism Hypo/hyperparathyroidism
Other disorders	Drug induced (e.g. statins) Motor neurone disease Parkinson’s disease

Table 17.2 Provisional EULAR/ACR PMR classification criteria scoring algorithm – required criteria: age ≥50 years, bilateral shoulder aching and abnormal CRP and/or ESR

Criteria	Points without ultrasound (0–6)	Points with ultrasound^* (0–8)
Morning stiffness duration >45 minutes	2	2
Hip pain or limited range of movement	1	1
Absence of RF or ACPA	2	2
Absence of other joint involvement	1	1
At least 1 shoulder with subdeltoid bursitis and/or biceps tenosynovitis and/or glenohumeral synovitis (either posterior or axillary) and at least 1 hip with synovitis and/or trochanteric bursitis	n/a	1
Both shoulders with subdeltoid bursitis, biceps tenosynovitis or glenohumeral synovitis	n/a	1

A score of 4 or more is categorized as PMR in the algorithm without ultrasound (US) and a score of 5 or more is categorized as PMR in the algorithm with US.

ACPA, anticitrullinated protein antibody; n/a, not applicable; RF, rheumatoid factor.

^*Optional ultrasound criteria.

Giant cell arteritis causes inflammation of the aorta and its major branches. Its clinical features are related to the affected arteries. The scalp is tender to the touch, and it can even hurt to wear spectacles. Jaw claudication may occur while chewing. Clinical signs vary according to the duration of the disease. In the early stages, the pulse is full and bounding, and the arteries tender (Figure 17.1). Later, fibrosis and repair may predominate, the artery may have a nodular indurated feel to it and the pulse is almost absent. Diplopia, partial or complete loss of vision and cranial nerve palsy may all occur if the condition remains untreated (Figure 17.2). It is important to consider atypical presentations as only half of patients report a temporal headache and 24% have no headache symptom at all. Systemic features, including polymyalgia symptoms, weight loss, fatigue and fever, may dominate, making diagnosis challenging.

Image described by caption. — **Figure 17.1** Markedly dilated temporal arteries in a 74‐year‐old man with giant cell arteritis. The arteries are visibly thickened and inflamed; palpation of the vessel is painful.

Source: Courtesy of Lester Mertz, MD

Nine gazes with temporary or permanent nerve palsy. — **Figure 17.2** Temporary or permanent nerve palsy can occur in association with cranial arteritis. Here, the sixth nerve is clearly involved

Late complications of large vessel involvement including aortic aneurysm and stenosis may complicate the disease course. Patients should be followed long term for aortic disease with computed tomography and aortic magnetic resonance imaging, complemented by ultrasonography of the aortic root and abdominal aorta by clinical and imaging assessment, as aneurysmal rupture is a cause of premature mortality in these patients. Temporal artery biopsy remains the ‘gold standard’ diagnostic test (Box 17.1). Histologically, lesions are characterized by a mainly lymphocytic and macrophage infiltrate with the presence of giant and epithelioid cells (Figures 17.3, 17.4). The CD3+ and T‐cell population comprises CD4+ or CD8+ subsets, in which CD4+ T‐cells predominate.