Musculoskeletal manifestations as the initial presentation of infective endocarditis.

To the Editor: Musculoskeletal manifestations of infective endocarditis may mimic rheumatologic disease. (1,2) In infective endocarditis (IE), despite microbial infection of the endothelial surface of the heart, patients may not manifest valvular involvement and the diagnosis may be delayed. (3) It is important to realize that the initial symptoms of IE may be musculoskeletal.

We reviewed three cases of endocarditis that presented as rheumatologic conditions. These patients were seen at Geisinger Medical Center in Danville, Pennsylvania, from May 1992 to June 1995. Musculoskeletal manifestations were the first symptom of endocarditis in these patients.

A 25-year-old male presented with a 2-month history of fever, chills, intense diaphoresis, and migrating polyarthralgias and low back pain. He presented to the emergency department and was thought to have ankylosing spondylitis. Rheumatologic evaluation revealed a temperature of 37.8[degrees]C. Grade I/VI mild, faint diastolic murmur heard best at the left lower sternal border was present. Both trochanteric bursae and sacroiliac joints were slightly tender to palpation. The sedimentation rate was 50 mm/h. There was no evidence of synovitis. The working diagnosis was sacroiliitis. The patient was evaluated in the rheumatology clinic. Transesophageal echocardiography revealed multiple nodularities on the anterior leaflet of the mitral valve suggestive of multiple vegetations, and he was started on antibiotics. Blood cultures revealed Streptococcus viridans. Subsequently, he underwent aortic and mitral valve replacement with a Starr-Edwards prosthesis. The patient had normal left ventricular size and function on 6-month follow-up echocardiography, and he was back to work without significant limitation in activity and function.

A 39-year-old male presented to a local emergency department after a 4-day history of fever spikes to 103[degrees]C and a 1-day history of right posterior calf discomfort. His physical examination was unremarkable except for calf tenderness. His laboratory results were normal except for a white blood cell count of 14,500 and a sedimentation rate of 65 mm/h. Radiographs and duplex scans of the right lower extremity were negative. These symptoms of spiking fevers and right calf pain were thought to be infectious in origin, with the working diagnosis being pyomyositis. Muscle infarction and vasculitis were also in the initial differential diagnosis.

The patient was transferred and admitted to Geisinger Medical Center. Magnetic resonance imaging of the leg revealed a 1.5 cm mass in the deep fascial plane of the right calf consistent with a calf infarct.

Transesophageal echocardiography revealed septic emboli and moderate to severe aortic insufficiency. Blood cultures revealed S viridans. Intravenous ampicillin (later changed to penicillin) and gentamicin were started. Tooth extraction for a dental abscess was performed. Aortic valve replacement was done 9 days after admission. On a 2-month follow-up, the patient had no rheumatologic symptoms and returned to work 3 months later.

A 63-year-old male presented to the rheumatology clinic with a 4-month history of neck pain, heel pain, and polyarthralgias. His physical examination was unremarkable; however, initial investigations revealed hemoglobin of 11.6 g/dL (13.5 to 15.5); sedimentation rate of 52 mm/h; and a positive rheumatoid factor (1:20). The patient was thought to have evolving rheumatoid arthritis and was treated with nonsteroidal anti-inflammatory drugs. One week later, the patient presented to the emergency department with fever, worsening pain, swelling, and limited range of motion in his right wrist. Physical examination revealed temperature of 39[degrees]C. The right wrist was swollen, red, and tender to touch with limited flexion and extension. The wrist was aspirated, but no fluid was obtained. No murmur was reported.

Given the history of positive rheumatoid factor, arthralgias, fever, weight loss, and anemia, the patient was admitted with the suspected diagnosis of infective endocarditis. This diagnosis was later confirmed with positive blood cultures for Streptococcus bovis and bacterial vegetations on the anterior and posterior mitral valve leaflets. Treatment with antibiotics resulted in resolution of rheumatologic symptoms 3 weeks after discharge.

We described three patients with infective endocarditis who initially presented with a 4-day to a 4-month history of musculoskeletal manifestations before diagnosis. The diagnosis and treatment of these patients were delayed.

Rheumatologic signs and symptoms as the initial presentation of infective endocarditis are frequently overlooked. The presence of musculoskeletal symptoms such as arthralgia, arthritis, low back pain, and myalgias in patients with IE is definitely more common than most clinicians suspect. Hunder's (4) review found that the musculoskeletal symptoms occur in one third to one half of the patients with bacterial endocarditis. The symptoms typically occur in one or several joints, usually large proximal joints. Fever out of proportion to joint findings in the setting of leukocytosis should lead to consideration of infective endocarditis as a diagnostic possibility even in the absence of a heart murmur. To avoid significant increase in morbidity and mortality in patients with IE, clinicians need to avoid delay in diagnosis and should initiate treatment with antibiotics immediately. Further adding to diagnostic delay is that patients with IE may have a positive rheumatoid factor in 19% of cases. (5) This may lead to misdiagnosis of rheumatoid arthritis in some cases. Clinicians should have a high index of suspicion, particularly in patients with fever, chills, new or change in heart murmur, arthralgias, arthritis, low back pain, and myalgias. In view of the morbidity and mortality of untreated bacterial endocarditis, it is mandatory that the diagnosis of bacterial endocarditis be included in patients with musculoskeletal symptoms to avoid life-threatening treatment delay.

References

1. Myers OL, Commerford PJ. Musculoskeletal manifestations of bacterial endocarditis. Ann Rheum Dis 1977;36:517-519.

2. Churchil MA Jr, Geraci JE, Hunder GG. Musculoskeletal manifestations of bacterial endocarditis. Ann Intern Med 1977;87:754-759.

3. Karchner AW. Infective endocarditis, in Braunwald E (ed): Heart Disease: A Textbook of Cardiovascular Medicine. Philadelphia, WB Saunders Company, ed 5, 1997, pp 1077-1104.

4. Hunder GG. When musculoskeletal symptoms point to endocarditis. J Musculoskeletal Med 1992;9:33-38.

5. Williams RC, Kumkel HG. Rheumatoid factors and their disappearance following therapy in patients with subacute bacterial endocarditis. Arthritis Rheum 1962;5:126.

Laura Llinas, MD

Thomas Harrington, MD

Department of Rheumatology

Geisinger Medical Center

Danville, PA