Muscle problems in HIV-infected persons include idiopathic polymyositis, polymyositis secondary to AZT toxicity, and pyomyositis. Weakness in the shoulder or hip girdle muscles, along with an elevated level of creatine phosphokinase (CPK) or aldolase or both, suggests polymyositis. AZT-induced polymyositis is similar to the idiopathic form, with muscle weakness, elevated CPK levels, and on muscle biopsy, myofibril necrosis with scant inflammation. In most cases, the patient improves gradually when AZT is discontinued, and the CPK level returns to normal.
Pyomyositis refers to solitary or multiple muscle abscesses that are not formed by local extension from superficial subcutaneous tissue. Although originally reported only in tropical climates, a number of cases were more recently described recently in North America, usually in healthy subjects but also in immune compromised hosts. The quadriceps muscle is most commonly involved, and 75% of patients have a single abscess.
Patients present initially with fever, and localized muscle pain. If the abscess is not deep in the muscle, redness, swelling, and a gradually developing woody induration may occur. If a painful area is found in a muscle during a physical examination, ultrasound, computed tomography, or magnetic resonance imaging is helpful in identifying and localizing the abscess or abscesses and in providing guidance during needle aspiration for identification of the pathogenic organism. S. aureus is responsible for the infection in the majority of cases, although a number of other bacteria have been recovered, including Escherichia coli and Salmonella enteritidis. After the area of the infection is defined, a diagnostic aspiration of the mass can be done under ultrasonic guidance. Systemic antibiotics usually cure a single small abscess, but large or multiple loculated abscesses often require surgical incision and drainage. Psoriatic arthritis with or without psoriasis occurs in HIV-infected persons. The prevalence of psoriasiform skin changes and psoriatic arthritis in HIV-infected persons probably is the same as that in non-HIV infected persons (1 to 2%), but the severity of the HIV-associated psoriasis and psoriatic arthritis tends to be worse. The foot and ankle are the most common, as well as the most severe, sites of inflammation in HIV-infected patients with psoriatic-like arthritis. Intense enthesopathy and dactylitis, especially in the feet, usually accompany the arthritis. The enthesopathy can be a major cause of disability. Frank synovitis and synovial effusions are less common, but can occur at the ankle and subtalar, metatarsal phalangeal, and interphalangeal joints of the feet. Sacroiliac and spine involvement may also occur. The radiologic appearance of these joints may mimic classic psoriatic arthritis, with "pencil and cup" deformities and osteolysis, even in the absence of frank psoriasis.
Nail involvement is a common presenting symptom of arthritis, especially in the distal interphalangeal joints of the hands and feet. Many patients with psoriatic skin manifestations or onycholysis have only these musculoskeletal findings and do not meet the criteria for a diagnosis of psoriatic arthritis. Nail involvement occurs in most patients who present with inflammatory articular symptoms. There is a high clinical correlation between skin and joint involvement, and joints may develop erosive changes and crippling deformities. Patients with HIV infection and psoriatic arthritis fall into one of two patterns of disease: either the articular disease is sustained and aggressive, progressing to joint erosions, or it is characterized by mild and intermittent joint involvement.
It is unknown whether HIV-associated psoriatic syndromes are strictly analogous to idiopathic psoriatic arthritis in non-HIV infected patients. Evidence against this possibility is that none of the human leukocyte antigen (HLA) alleles found in patients with idiopathic (non-HIV) psoriasis vulgaris or psoriatic arthritis (such as Cw6, B13, or B17) occur with greater frequency among HIV-infected patients with psoriatic-like arthritis.
The treatment of spondyloarthropathy in HIV-infected patients is similar to that for non-HIV infected patients. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as indomethacin (75 to 150 mg per day), can be used initially for the joint symptoms, but results have been disappointing. There are few data on second-line agents such as gold, methotrexate, and azathioprine. There are reports that phenylbutazone (100 mg 3 times per day) is an effective drug for this arthritis, and neutropenia has not been a problem even in patients receiving AZT concurrently.
Patients in whom psoriatic skin or joint disease does not respond to NSAIDs may be treated with phenylbutazone (100 mg 3 times a day) or sulfasalazine (1 to 2 g per day). Etretinate may also be helpful. The use of psoralen and pulsed UV actinotherapy (PUVA) has helped the skin and joints of some HIV-infected individuals with psoriatic arthritis.
At our institution, treatment of patients with severe arthritis with low doses of methotrexate (5 to 10 mg per week) has led to rapid (< 4 weeks) improvement in inflammatory joint symptoms as well as improvement in skin lesions. Methotrexate can be given until the skin and joint disease is under control, then slowly tapered by 2.5 mg per month, aiming for a maintenance dose of 5 mg per week. Patients must be monitored closely, because there are anecdotal reports of progressive immunodeficiency and opportunistic infections in HIV-infected individuals with Reiter's syndrome who are treated with methotrexate. Systemic glucocorticoid use is generally discouraged because of increased risk of infection, but intra-articular steroid injection (every 4 to 6 months) may provide substantial relief to individual arthritic joints.
the patient to determine whether weakness accompanies the pain, and whether the pain is generalized or localized to one muscle group; localized pain may be a sign of polymyositis, whereas generalized pain suggests a systemic process. It is also important to determine whether the patient is taking zidovudine (AZT), and whether the muscle pain began soon after initiation of the drug therapy.
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