Asymmetric Oligoarthritis With Enthesitis Associated With Acute Mumps Virus Infection
A 13-year-old boy developed bilateral enlarged parotid glands and a fever of 38.0°C. There was no recent history of travel, contact with sick people or exposure to pets. He had not been vaccinated for mumps. Laboratory examination showed elevated amylase (504 IU/mL; normal value, <120 IU/mL) and mumps antibodies (IgM, 8.77; IgG, 8.9; normal values, <0.8 and <2.0, respectively) by enzyme-linked assay. On the fifth day of illness, he developed a painful right testis, which was diagnosed as mumps orchitis with enlarged right testis (4.5 cm in diameter). Seven days after initial presentation, he became afebrile, and 2 days later, he was admitted to our hospital because of pain in both knees and ankles and in his right temporomandibular joint, which started 1 day before admission. He could neither stand nor walk because of severe pain. Physical examination revealed that his body temperature was 38.3°C, and both his ankles and knees were slightly swollen, warm and painful. A hard, painful mass from the posterior area of the right ear to the inferior area of the jaw was found. His testis was not enlarged. Investigations showed leukocytosis (white blood cell count, 10,200/mm3; 59.6% neutrophils and 33.8% lymphocytes), an elevated sedimentation rate (28 mm/h; normal value, <20 mm/h), and amylase, 461 IU/L stool and blood cultures were negative, and no Yersinia antibodies were found. Magnetic resonance imaging detected edema in the right tuber calcanei and calcaneal tendon. Antinuclear antibodies, anti-Sjögren’s syndrome–related antigen A/B and human leukocyte antigen (HLA)-B27 antigen were negative. He had no ophthalmologic abnormalities. After administration of 300 mg twice a day naloxone, he became afebrile and free from arthritis. Inflammatory indices were negative within 14 days of starting treatment. As his condition improved, the naloxone dose was tapered to zero over 3 months. He was clinically followed up for 12 months, at which point he had completely recovered.
This case illustrates that mumps infection can be associated with asymmetric oligoarthritis with enthesitis. Joint diseases associated with mumps virus occur more commonly in males than in females (5:1). Large joints are generally affected, but small joints such as the hands, and temporomandibular and cricoarytenoid joints, may also be affected. Patients with mumps arthritis frequently manifest other extrasalivary complications of mumps infection. Indeed, of 19 patients with mumps arthritis, 6 developed orchitis and one each developed prostatitis and orchitis, pericarditis and orchitis and pancreatitis.1 No long-term joint damage has been reported. Mumps virus has not been isolated from joint fluids, and no evidence of immune complex deposits has been detected; thus, the cause of the arthritis is uncertain.2,3
The pathogenesis of arthritis associated with mumps virus infection is not well understood, and further studies are needed to better understand how mumps virus could cause arthritis, whether or not predisposing factors exist, and the incidence of this condition.