Polymyalgia Rheumatica and Giant Cell Arteritis



Polymyalgia Rheumatica and Giant Cell Arteritis


Richard Stern





KEY POINTS


Polymyalgia Rheumatica (PMR)



  • PMR is a common illness in individuals older than 60 years and is manifested by proximal arthralgia/myalgia, morning stiffness, gelling, and an elevated sedimentation rate.


  • Critical to the diagnosis of PMR is a dramatic response to low-dose corticosteroids.


  • The symptoms of PMR are nonspecific, and other myalgic illnesses should be excluded.


Giant Cell Arteritis (GCA)



  • GCA is a type of vasculitis, which affects the branches of the external and internal carotid artery, and it can cause permanent blindness when the retinal vessels are involved.


  • Although visual loss is the most well-known symptom of GCA, visual loss, in most cases, is preceded for some time by headache. Partial visual loss (amaurosis fugax and unilateral blindness) may precede total visual loss.


  • If GCA is suspected, the patient should immediately be started on high-dose steroids (60 to 80 mg prednisone daily). Moreover, treatment should not be delayed until a temporal artery biopsy is done.



  • PMR frequently occurs in patients with GCA.


  • GCA can also involve large elastic vessels causing claudication, aneurysms, or even coronary disease.


POLYMYALGIA RHEUMATICA

Polymyalgia rheumatica (PMR) is a syndrome in elderly patients with an elevated erythrocyte sedimentation rate that is manifested by proximal aching, soreness, and stiffness that cannot be attributed to a defined rheumatic, infectious, metabolic, or neoplastic disorder.


I. ETIOPATHOGENESIS

There is an association between PMR and human leucocyte antigen-DR4 (HLA-DR4).


II. PREVALENCE

PMR affects approximately 1 in 1,000 persons in the US population who are older than 50 years.


III. CLINICAL MANIFESTATIONS



  • Sixty percent of the patients are women. Most patients present after their fiftieth year, and the peak incidence is between ages 60 and 80 years. Rarely, cases have been observed in younger patients.


  • Proximal soreness and stiffness. PMR is characterized by chronic, symmetric aching and stiffness of the proximal joints and muscles. These symptoms are most prominent in the shoulder and pelvic girdles and neck, but distal muscle groups may also be involved, although to a lesser extent. It is not unusual for symptoms to be restricted to the upper extremities. Aching and stiffness are worse in the morning, usually lasting more than 30 minutes and occurring after a period of inactivity (gelling). Aching may be severe and incapacitating. Strength is often difficult to evaluate because pain is present; however, this parameter should be normal.


  • Constitutional symptoms. Patients with PMR frequently complain of malaise and fatigue. Fever is usually low-grade, but temperature may occasionally reach 102°F. Night sweats may occur. PMR may rarely present with a fever of unknown origin. Anorexia and weight loss may be prominent features and suggest malignancy; however, no direct association of PMR with neoplastic disease has been proven. Yet, an age-appropriate malignancy assessment is appropriate. Depression, usually mild, is not infrequent.


  • Joints. Most patients have poorly localized tenderness over their joints, especially prominent over the shoulders and hips. Moderate bland effusions can be seen in the knees and occasionally in the wrists, but they do not dominate the clinical picture as they do in rheumatoid arthritis (RA). Carpal tunnel syndrome has also been noted. Ultrasonography and magnetic resonance imaging (MRI) have shown that proximal joint symptoms reflect soft tissue inflammation such as tendinitis and bursitis.


  • Giant cell arteritis (GCA), also called temporal (cranial) arteritis (TA). PMR and GCA are companion disorders that are part of a continuum of an inflammatory disorder. It has been estimated that approximately 10% of patients with PMR may have GCA and 50% of patients with GCA may have characteristic PMR symptoms.


IV. DIAGNOSTIC INVESTIGATIONS



  • PMR should be considered in patients older than 50 years who complain of proximal arthralgia and myalgia associated with morning stiffness lasting over 30 minutes.


  • Laboratory tests



    • An elevated Westergren erythrocyte sedimentation rate is the laboratory hallmark of PMR; it is usually in excess of 50 mm/hour and may exceed 100 mm/hour. There is evidence that PMR can occur with normal sedimentation rates (20 to 30 mm/hour) but sedimentation rates below 10 mm/hour would be very unusual.


    • Normocytic normochromic anemia is seen in approximately 50% of patients.


    • Immunologic studies. The frequency of rheumatoid factors, antinuclear antibodies, and other autoreactive antibodies is not higher than that of age-matched controls.


    • Muscle enzyme levels (e.g., creatine kinase, serum glutamic-oxaloacetic transaminase, lactic dehydrogenase, and aldolase) are normal.



  • Plain radiographic findings are normal but MRI and ultrasonography of proximal joints demonstrate soft tissue inflammation such as tendinitis and bursitis. These tests, however, are not routinely performed.


  • Electromyographic findings have been normal, but this test is not a part of the diagnostic workup of this disorder.


  • Muscle biopsy histology. Myositis is not seen.


  • Synovial fluid and tissue studies



    • Leukocyte counts in joint fluid range between 1,000 and 8,000 mm3, with a preponderance of lymphocytes. It is rare to find synovial fluid in joints in PMR.


    • Synovial biopsy specimens, rarely needed or available, reveal mild synovial proliferation with slight lymphocyte infiltration.


V. DIFFERENTIAL DIAGNOSIS

The diagnosis requires exclusion of other syndromes associated with significant proximal soreness and stiffness, erythrocyte sedimentation rate (ESR) elevation, and constitutional symptoms, such as the following:

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Jul 29, 2016 | Posted by in RHEUMATOLOGY | Comments Off on Polymyalgia Rheumatica and Giant Cell Arteritis

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