Case Presentation: A healthy 34-year-old female presented to the hospital with severe left lower extremity pain. Patient endorsed 4 days of progressively worsening left upper thigh and hip pain that caused her to become bed bound, prompting her to come in. She also reported fevers, chills, cough, and myalgias but denied vomiting, diarrhea, numbness, or focal weakness. She denied trauma, travel, sexual activity, or IV drug use. On admission, she was afebrile, normotensive, and mildly tachycardic to 113 bpm. On exam, she was tearful with any left hip movement and she had diffuse left thigh and hip tenderness without erythema or fluctuance. Laboratory testing was notable for CRP 37.2 mg/dL, ESR 44 mm/h, and normal CK. A respiratory viral panel was positive for rhinovirus/enterovirus. Other infectious and autoimmune workup was negative including blood cultures, chest x-ray, urine Chlamydia and Neisseria testing, Lyme serologies, ANA, RF, anti-CCP, and HLA-B27. MRI of the left hip showed a small joint effusion. An arthrocentesis of the left hip yielded cloudy, serous fluid containing 35,000 nucleated cells with 85% neutrophils and 3,000 RBCs, with no birefringent crystals and negative gram stain. Despite escalating pain medications, including IV opioids, her pain did not improve. Out of initial concern for septic arthritis, IV vancomycin was initiated but stopped after no improvement over 48 hours and with negative joint aspiration cultures. Eventually, in conjunction with a rheumatology consultation, a clinical diagnosis of reactive arthritis due to respiratory viral illness was made. IV steroids were started. Patient’s symptoms and inflammatory markers rapidly improved and she was discharged home with a 30-day steroid taper.
Discussion: This case is unique because it highlights that reactive arthritis (ReA) is a clinical diagnosis and in rare cases, it can be associated with respiratory viral illness. ReA is an acute inflammatory arthritis triggered by extra-articular microbial infections, commonly gastrointestinal and urogenital bacterial infections. Viral respiratory causes are rare though SARS-CoV-2 has been associated with ReA in several case reports. Rhinovirus and enterovirus have rarely been reported to be associated with ReA. One case report discussed ReA associated with rhinovirus infection, but there was simultaneous Chlamydia pneumoniae infection, which is a known trigger. Given that rhinovirus and enterovirus were the only identified pathogens, this may represent a rare case of ReA triggered by rhinovirus/enterovirus respiratory infection. Though a positive HLA-B27 can be a marker suggestive of ReA, currently there are no established diagnostic criteria. Our team relied on clinical information to make the diagnosis in a case where labs and imaging were non-diagnostic. Initial therapy with NSAIDs and glucocorticoids is indicated for symptomatic relief of ReA as highlighted in our case.
Conclusions: Reactive arthritis should be considered in patients presenting with acute oligoarticular arthritis and recent gastrointestinal, genitourinary, or respiratory infection. A multitude of organisms have been associated with this condition, and suspicion should remain even if common triggers are not identified. When septic and crystalline arthritides have been ruled out, anti-inflammatory and glucocorticoid medications should be considered to relieve symptoms.