Summary

Polymyalgia rheumatica is an inflammatory disorder that affects persons older than 50 years old. Patients with polymyalgia rheumatica often present with pain and stiffness in their neck, shoulders and hips, fatigue, weight loss and low grade fever. Polymyalgia rheumatica is closely related to another inflammatory disorder called giant cell arteritis. Symptoms of polymyalgia rheumatica may be non-specific and mimic other medical and degenerative conditions, and it might not be easily recognized in elderly patients. The erythrocyte sedimentation rate (ESR) is the most useful laboratory test for diagnosing these conditions. Symptom relief in response to corticosteroid therapy is rapid. Early detection and appropriate treatment may totally change the lives of these patients. We present here a 70 years old lady who complained of debilitating neck and shoulder pain.

摘要

風濕性多肌痛是一種五十歲以上人士的炎症疾病。患者多呈現肩頸和臀部疼痛及僵硬，疲倦，體重下降及輕微發熱。它和巨細胞性動脈炎有密切關係。風濕性多肌痛可能沒有特定病徵，而和其它內科及退化性疾病的病徵相似。在年長病人來說，它可能不易被察覺。紅細胞沉降率是最有用的化驗診斷方法。類固醇治療能迅速舒緩徵狀。及早診斷及適當治療或會完全改變病人的生活質數。本文敘述了一位七十歲患有嚴重肩頸痛女士的個案。

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Introduction

Polymyalgia rheumatica is not an uncommon condition which affects persons older than 50 years of age and causes substantial morbidity. Symptoms of polymyalgia rheumatica may be non-specific and mimic other medical or degenerative conditions; hence it might not be easily recognized in elderly patients. Early detection and appropriate treatment may totally change the lives of these patients. We present here a 70 years old lady who complained of debilitating neck and shoulder pain to illustrate the difficulties in making the diagnosis of polymyalgia rheumatica and a review of this condition.

Case report

A 70 years old lady presented to our clinic with generalized malaise and muscle pain predominately in her neck and shoulder regions for a few months. The pain was so severe that she found doing daily housework was difficult and gave up all her interests and hobbies. She did not have any fever, stiffness, weight loss, or suffered any injury. She was seen by different doctors with various different diagnoses such as osteoarthritis, muscle sprain and bilateral frozen shoulders. Finally she consulted an orthopaedic surgeon and X-ray of neck and shoulders revealed degenerative changes. Pain killers were prescribed and a course of physiotherapy was given. However, there was only little response to this treatment. The patient was mildly depressed and worried greatly about a worsening of her condition and her ability to self care.

At physical examination, the patient appeared distressed. She was afebrile. All muscle tone and power were normal but there was tenderness on palpation of the paracervical and trapezius muscles. The range of movements in both shoulders and neck were slightly decreased because of the pain. Blood tests were performed and results were as follows:

Complete blood picture

Hb		10.3 g/dL		Low		(11.7-15.0)
RBC		3.68 X 1012 L		Low		(3.80-5.20)
HCT		0.317 L/L		Low		(0.360-0.457)
MCV		86 fL				(79-103)
MCH		28 pg				(27-34)
MCHC		32 g/dL				(31-34)
RDW		12.3 %				(10.0-14.0)
Rheumatoid factor		<20 u/ml
Antinuclear Antibody		No antibody detected
ESR		111 mm/hr

Her condition was reviewed again during the follow-up consultation. There was no headache, visual disturbance or jaw claudication. Physical examination did not reveal any abnormality over the eyes, in the jaws, temporal arteries and her neurological system. She was then referred to the medical specialist for further investigation and management.

Four months later, the patient came back for an annual health assessment. She still had the muscle pain and malaise. She reported that all investigations done in the medical department were "normal". She was currently followed up by the orthopaedic surgeon but her pain still persisted. In view of her failure to respond to her treatment and her debilitating neck and shoulder pain, we suspected she might be suffering from polymygia rheumatica. Her blood erythrocyte sedimentation rate (ESR) was rechecked and was elevated to greater than 120mm/hr. She was then referred to a rheumatologist where the diagnosis of polymyalgia rheumatica was confirmed. Prednisolone was given and there was a dramatic response after a few days. Her quality of life improved and she could return to her previous functional status.

Discussion

Polymyalgia rheumatica is an inflammatory disorder that affects one in 200 persons older than 50 years of age. The mean age at diagnosis is 70 years old. It is twice as common in women as in men.¹ Polymyalgia rheumatica is closely related to another inflammatory disorder called giant cell arteritis which is more dangerous as it may lead to sudden blindness.

The pathogeneses of polymyalgia rheumatica and giant cell arteritis are uncertain. Autoimmune responses are believed to play a prominent role. Similar cellular immune responses involving T-cells, antigen-presenting cells, macrophage-derived inflammatory cytokines, genetic human leucocyte antigen molecules and macrophages are found in both conditions.² In fact, polymyalgia rheumatica may involve a milder and more widespread immune reaction, whereas giant cell arteritis involves a more intense and focal form of the same process.

Patients with polymyalgia rheumatica often present with pain and stiffness in the neck, shoulders and hips, fatigue, weight loss and low grade fever. Shoulder pain is the most common symptom. Stiffness is greatest in the morning and lasts for 30 to 60 minutes after the patient rises. Some patients may experience swelling of their hands and feet. Weakness is rarely a feature of polymyalgia rheumatica although decreased strength is generally the result of disuse atrophy.³

The physical findings may include some limitation of the range of movement in the neck, shoulders and hips secondary to pain in the associated proximal muscles, inflammation of the bursas in the shoulder and hip regions, tenderness of upper arms and thighs, low grade fever and reduction in body weight. Synovitis, carpal tunnel syndrome and peripheral oedema may be noticed in some cases.³

As many as one fourth of the patients with polymyalgia rheumatica may have coexisting giant cell arteritis.¹ It is important to look for symptoms of giant cell arteritis which include new onset of headache, visual loss, diplopia and jaw claudication. Temporal artery biopsy may be indicated if there is any suspicion of coexisting giant cell arteritis because the complications and treatment of these conditions are different.

Differential diagnoses of polymyalgia rheumatica include osteoarthritis, rheumatoid arthritis, malignancy, depression, chronic infection and other connective tissue diseases.⁴ The ESR may be increased in many of these conditions. Therefore history, physical examination, imaging and laboratory tests should focus on differentiating polymyalgia rheumatica from these disorders. As the symptoms of polymyalgia rheumatica are rather non-specific and also occur together with other musculoskeletal diseases in the elderly, early detection of polymyalgia rheumatica requires a high level of clinical suspicion. In an uncertain situation, a trial of corticosteroid given in low dosage may be helpful because rapid relief of symptoms is a characteristic of polymyalgia rheumatica.

The erythrocyte sedimentation rate is the most useful laboratory test for diagnosing polymyalgia rheumatica and giant cell arteritis. Elevation of ESR is found in more than 80 percent of the patients with polymyalgia rheumatica or giant cell arteritis.³ The upper limit of normal ESR is estimated using the following formulas:

Men:	age /2
Women:	(age + 10)/2

Patients with polymyalgia rheumatica may also have normocytic anaemia and an elevated alkaline phosphate level. Temporal artery biopsy is the gold standard for a diagnosis of giant cell arteritis. The use of ultrasonography and positron emission tomography in the diagnosis of polymyalgia rheumatica and giant cell arteritis is still experimental.

Early experiences suggest that polymyalgia rheumatica is self-limiting and runs its course in one to three years.¹ Polymyalgia rheumatica generally is not commonly associated with the serious complications of giant cell arteritis such as blindness or development of aortic aneurysm. However, untreated patients often have an impaired quality of life; with appropriate treatment, survival is similar to that in unaffected persons of the same age.

Polymyalgia rheumatica and giant cell arteritis are treated with corticosteroids. High dosage (40-60mg per day) is used for giant cell arteritis and low dosage (10-20 mg per day) is used for polymyalgia rheumatica.⁵ For patients with polymyalgia rheumatica, the response to corticosteroid therapy is usually rapid and dramatic, usually within three to four days after initiation of treatment. If patients respond to the treatment, the corticosteroid dosage should be continued until ESR normalizes. This usually occurs in approximately four weeks' time. Tapering should then take place at a rate of not more than 1mg per day every month.⁵ Supplementation of calcium or bisphosphonates may decrease the risk of osteoporosis and subsequent fracture resulting from the prolonged use of steroid.

High doses of nonsteroidal anti-inflammatory drugs (NSAID) have been used to treat polymyalgia rheumatica. However, most patients do not respond well to NSAIDs. Others agents such as methotrexate, azathioprine should only be considered in certain cases that are difficult to control.

Elderly patients tend to have non-specific symptoms. Most of them have multiple vague complaints and are unable to give a detailed history and they may have multiple pathologies. It is a real challenge for doctors to distinguish minor ailments from serious medical conditions. Family physicians are in an unique and advantageous position to take up this challenge. We should always think of polymyalgia rheumatica in elderly patients presenting with chronic bilateral shoulder pain, and check ESR if there is any clinical suspicion. We should review our diagnosis and also think of other possibilities even though the preconceived diagnosis is confirmed by certain tests or by other colleagues, and when symptoms persisted after treatment. Serious medical problems may coexist with the common degenerative conditions.

Key messages

1. Polymyalgia rheumatica is an inflammatory disorder that affects one in 200 persons older than 50 years of age.
2. Polymyalgia rheumatica is closely related to another inflammatory disorder called giant cell arteritis which is more dangerous as it may lead to sudden blindness.
3. Patients with polymyalgia rheumatica often present with pain and stiffness in their neck, shoulders and hips, fatigue, weight loss and low grade fever.
4. Symptoms of giant cell arteritis include new onset headache, visual loss or diplopia and jaw claudication.
5. The erythrocyte sedimentation rate is the most useful laboratory test for the diagnoses of polymyalgia rheumatica and giant cell arteritis.
6. For patient with polymyalgia rheumatica and giant cell arteritis, symptom relief in response to corticosteroid therapy is rapid.

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Reference