Presentations

Abstract

Introduction: Fever of unknown origin has a broad differential, including infectious and rheumatologic etiologies. The following case describes a febrile patient with symptoms affecting multiple organ systems, that were all connected by an unusual diagnosis.

Case Information: A 42-year-old male with recently diagnosed rheumatoid arthritis presented with right upper quadrant abdominal pain. He had been taking methotrexate, indomethacin, and acetaminophen for a 6-month history of subjective fever, fatigue, and diffuse arthralgias. He also had oral ulcers on his tongue and lower lip. Initial liver function tests were significant for AST 623, ALT 527, alkaline phosphatase 162, and total bilirubin 1.4. Patient was subsequently admitted for acute liver injury of unknown etiology, and methotrexate was discontinued. Methotrexate, acetaminophen, salicylate, and phosphatidylethanol levels were within normal ranges. Sedimentation rate was 77 and C-reactive protein was 5.8. Hepatitis panel was negative for acute disease; smooth muscle, ANCA, LKM-1, and mitochondrial M2 antibodies were negative. Elastography resulted in increased liver echogenicity, with mild fibrosis. ANA, rheumatoid factor, and anti-CCP antibody were negative. Plain films of his extremities and sacroiliac joints were unremarkable other than mild soft tissue swelling of the right hand. During admission, transaminitis improved, but the patient developed repeated febrile episodes and new dyspnea on exertion with hypoxemia. Leukocytosis peaked at 16,300; CT imaging was negative for pulmonary emboli and showed scattered pulmonary nodules with peripheral predominance. Infectious disease and pulmonology were consulted. A broad workup followed, only significant for a positive respiratory culture of H.influenzae that was treated with ceftriaxone. Oral ulcer biopsy was positive for HSV, and a lung biopsy from bronchoscopy yielded abundant macrophages. After 10 days, the patient had an afebrile period of 48 hours and was discharged with a diagnosis of fever of unknown origin. The patient had continued follow-up in the outpatient setting, including PFTs that indicated interstitial lung disease. Three months after the inpatient admission, the patient presented to outpatient pulmonology. He endorsed bilateral hand pain and recent facial swelling with erythema around both eyes; physical exam was significant for Gottron's papules. He was given a short course of prednisone, and autoimmune workup was reordered, along with creatine phosphokinase and myositis panel. CPK was not elevated, but the myositis panel was positive for MDA-5 antibody. With a new diagnosis of anti-MDA-5 dermatomyositis, the patient had expedited referrals to rheumatology and dermatology, and began an immunosuppressive regimen of mycophenolate and continued prednisone. He has reported significant improvement since.

Discussion/Clinical Findings: Discovered in 2009, anti-MDA-5 dermatomyositis is a subtype of dermatomyositis that can be hypomyopathic or amyopathic, with low or no muscle inflammation. Symptoms include fever, arthralgias without joint erosions, oral and skin ulcers, Raynaud's disease, transaminitis, and dermatologic signs including Gottron's papules and heliotrope rash. There is also a strong association with ILD, which can contribute to mortality. Management is focused on immunosuppression and symptom control.

Conclusion: In conclusion, lack of muscle involvement does not exclude dermatomyositis. Anti-MDA-5 dermatomyositis can be difficult to identify but can explain a constellation of symptoms.