Review Question - QID 217604

This patient presents with bilateral wrist and metacarpophalangeal joint pain and stiffness in the setting of a recent exposure to sick children, which is suggestive of parvovirus B19 infection. Diagnosis of parvovirus B19 can be secured with IgM antibody assays against the viral capsid antigens.

Parvovirus B19 infection, also known as erythema infectiosum or fifth disease in children, is caused by its eponymous single-stranded DNA virus. Infected children present with a mild febrile illness with the pathognomonic “slapped cheek” facial rash. Other clinical syndromes include transient aplastic crises in patients with hemolytic disorders, hydrops fetalis in fetuses, and pure red blood cell aplasia in immunocompromised patients. In healthy adults, the predominant (and often only) finding is arthropathy (e.g., arthritis, arthralgia) affecting the small joints of the hands, wrists, knees, and/or feet. Many adults also develop a rash, but not the classic “slapped cheek” rash found in children. In adults, the rash is erythematous and non-specific in appearance and distribution, although it can take on purpuric characteristics as well. Diagnosis can be secured with an antibody assay to detect IgM against the viral capsid antigens; however, the diagnosis is often suspected clinically. Treatment is supportive, as the arthritis typically self-resolves within 3 weeks. Non-steroidal anti-inflammatory drugs can be used for pain control.

Moore reviews the clinical syndromes caused by human parvovirus B19. The author notes that joint symptoms occur in 60% of infected adults, especially in women. They recommend further evaluation for other systemic causes of pain though if there are associated symptoms as this virus does not lead to rheumatoid arthritis or lupus.

Incorrect Answers:
Answer 1: Antinuclear antibody is commonly ordered in the work-up of suspected autoimmune disorders such as systemic lupus erythematosus (SLE). SLE is a multi-organ disorder, presenting with fatigue, fever, malar rash, myalgias, weight loss, arthritis, and/or serositis. Multiple blood cell lineages (e.g., red blood cells) are also reduced. Specific diagnostic criteria must be met for a diagnosis of lupus. This patient has an isolated arthritis.

Answer 2: Diagnostic arthrocentesis is used in the work-up of suspected septic arthritis. Septic arthritis presents with joint pain, erythema, warmth, and edema. Patients typically have severely limited range of motion of the affected joint due to pain. This patient has multiple, symmetrically affected joints and full range of motion despite pain.

Answer 3: Erythrocyte sedimentation rate, a nonspecific marker of inflammation, can be used in the work-up of reactive arthritis (although it is frequently negative). Reactive arthritis presents with a symmetric oligoarthritis (typically of the lower extremities), dysuria, and conjunctivitis with a preceding genitourinary infection. This patient has an isolated arthritis and no clear preceding infection.

Answer 4: IgM against a fragment of IgG refers to rheumatoid factor, which is measured in the work-up of rheumatoid arthritis. Rheumatoid arthritis can also present with bilateral wrist and metacarpophalangeal joint arthritis, but the time course is typically chronic and stiffness is typically worse in the morning. This patient’s stiffness occurs throughout the day and her history of exposure to sick children with facial rashes makes parvovirus infection more likely.

Bullet Summary:
In adults, human parvovirus B19 infection presents with predominantly arthritis/arthralgia symptoms and can be diagnosed with a serologic assay for IgM against viral capsid antigens.