Polymyalgia Rheumatica

Polymyalgia rheumatica (PMR) is a syndrome characterised by pain or stiffness, predominantly in the neck, shoulders, upper arms, and hips, though it can affect the entire body. This condition can manifest suddenly or develop gradually over time. Most patients experience morning pain, but some may suffer throughout the day or develop symptoms in the evening.

Signs and Symptoms

PMR presents with a broad spectrum of symptoms. The hallmark is moderate to severe pain and stiffness in the neck, shoulders, upper arms, thighs, and hips. These symptoms can inhibit daily activities, especially after waking up or sleeping. Pain might also be localised to the groin area and buttocks. Other notable symptoms include fatigue, lack of appetite, anaemia, an overall feeling of illness, flu-like symptoms, low-grade fever, night sweats, weight loss, and swollen hands and feet due to retained moisture.

Approximately 15% of individuals diagnosed with PMR also have temporal arteritis, also known as giant cell arteritis (GCA). Conversely, about 50% of those with GCA have PMR. Symptoms of GCA include headaches, scalp tenderness, jaw or facial soreness, distorted vision, aching limbs due to decreased blood flow, and fatigue.

Causes

The aetiology of PMR is not well-understood. The pain and stiffness are attributed to the activity of inflammatory cells and proteins within the body's immune system, particularly in tissues surrounding the affected joints. During PMR, white blood cells attack the joint linings, causing inflammation. Genetic predisposition plays a role, with persons of Northern European descent being at higher risk. Infections may also be contributing factors, especially when symptoms appear suddenly. Studies have suggested a possible viral connection, implicating viruses such as the adenovirus, human parvovirus B19, and the human parainfluenza virus. However, no conclusive link has been established between these viruses and PMR.

Diagnosis

Diagnosing PMR is challenging as no specific test exists. Diagnosis involves ruling out other conditions that cause muscle pain and inflammation. A thorough physical examination, along with a detailed patient history, helps narrow down the diagnosis. Limitation in shoulder motion or swelling in the joints of the wrists or hands can be indicative.

Blood tests such as the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels are commonly used. ESR measures the rate at which red blood cells settle in a test tube, with faster rates suggesting inflammation. CRP, produced by the liver in response to injury or infection, is usually elevated in PMR patients. However, both tests are non-specific.

Given the association between PMR and GCA, a biopsy of the temporal artery may be conducted to check for GCA.

Treatment

Prednisone, a corticosteroid, is the primary treatment for PMR. Dramatic improvement in symptoms should be evident within three days of starting a daily dose of 10–20 mg. If no improvement occurs, the diagnosis should be reconsidered. Nonsteroidal anti-inflammatory drugs (NSAIDs) are ineffective initially but may be used alongside corticosteroids for maintenance.

Patients are encouraged to exercise and follow a healthy diet to support their immune system and maintain muscle and bone strength. A diet rich in fruits, vegetables, whole grains, and low-fat meat and dairy is recommended, while high refined sugars and salt should be avoided. Research from the UK suggests that a falls assessment at diagnosis and regular treatment reviews can benefit individuals with PMR.

Epidemiology

PMR predominantly affects adults over 50, with the average age of onset around 70. Women are twice as likely to develop PMR compared to men. Caucasians, particularly those of Northern European origin, are more susceptible, with Scandinavians being especially vulnerable. Approximately 50% of those with GCA also have PMR.

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Self-assessment MCQs (single best answer)

What is the hallmark symptom of Polymyalgia Rheumatica (PMR)?

Which of the following is true about the onset of PMR symptoms?

What percentage of patients with PMR are also diagnosed with temporal arteritis (GCA)?

Which blood tests are commonly used in the diagnosis of PMR?

Which of the following treatments is primarily used for PMR?

Which population is most susceptible to PMR?

What should be reconsidered if there is no improvement in PMR symptoms within three days of starting a daily dose of prednisone?

Which symptoms may indicate the presence of temporal arteritis (GCA) in a patient with PMR?

Which of the following is NOT a common symptom of PMR?

Which lifestyle recommendations are suggested for patients with PMR?