NEJM Clinical Pearls 2007/10/31
Acute Symmetric Polyarthritis
The differential diagnosis for systemic inflammatory arthritis includes autoimmune inflammatory arthritis (such as rheumatoid arthritis, psoriatic arthritis, and systemic lupus erythematous), microcrystalline arthritis (including gout or pseudogout), and infectious or postinfectious arthritis (including acute rheumatic fever from group A streptococcus, reactive arthritis from bowel or genitourinary infection, or Lyme disease).
Viruses that Can Cause Arthritis
Parvovirus B19 infection can present with acute arthritis; this occurs more often in adults than in children. The most common clinical presentation of Parvovirus B19 in childhood is erythema infectiosum or fifth disease, (“slapped cheek” appearance and a reticular rash on the torso and limbs). In contrast, adults with parvovirus B19 infection often present with a more debilitating, influenza-like illness; and as many as 60% of adults with infection present with clinically important arthralgias or arthritis. Adenovirus, coxsackievirus, Epstein–Barr virus, cytomegalovirus, rubella, mumps, and retroviruses can also cause arthralgias or acute arthritis.
Q: Does a negative rheumatoid factor rule out rheumatoid arthritis?
A: Rheumatoid-factor seronegativity does not rule out rheumatoid arthritis, but it does reduce the likelihood that a patient has the disease. However, it is of note that the occasional presence of autoantibodies, including rheumatoid factor antibodies, may be found in the presence of viral infections, albeit at a low titer, without the presence of rheumatoid arthritis.
Q: Intrauterine infection with parvovirus B19 can cause what serious outcome?
A: Intrauterine infection with parvovirus B19 is a major cause of hydrops fetalis. The estimated risk of fetal infection when a woman is infected with parvovirus during pregnancy is 30% with a 5 to 9% risk of fetal loss. Infection during the second trimester appears to pose the greatest risk of hydrops fetalis.