CC: Joint Pain
HPI: This is a 32 year old male with history of chlamydia and new diagnosis of HIV who presents for painful joint swelling in bilateral knees and wrists for 5 days. He reports that approximately 3 weeks prior to admission, he experienced 1 week of abdominal pain, diarrhea, and fevers. While the GI symptoms resolved, he has had on and off fevers since. Five days prior to admission, he began to have bilateral wrist pain with swelling which then progressed to to his left knee followed by his right knee over the course of a few days. His social history is notable for being sexually active with both males and females with greater then 30 partners over the last few years. His exam is pertinent for bilateral wrist and knee swelling, warmth and tenderness. There is difficulty ranging the joints with both passive and active motion. Skin and lymph node exam is normal though. Given history and exam consistent with an inflammatory oligoarthritis in the setting of recent gastrointestinal infection, reactive arthritis high on the differential but could not rule out disseminated gonococcal infection or atypical presentation of crystalopathy, septic joint, or rheumatoid arthritis. Joint aspiration from wrist significant for a leukocyte count of >90,000 with >75% PMNs so patient initiated on antibiotic therapy for septic joint treatment. However further studies on synovial fluid unrevealing including gram stain, culture, and crystals. Serologies were also sent which showed a negative ANA, mildly elevated RF, and negative Anti-CCP. Mucosal swabs for gonorrhea negative and though patient high risk, without other findings of disseminated gonococcal infection (DGI) like tenosynovitis, pustular rash, and migratory arthritis nor positive cultures from non-mucosal sites, DGI considered unlikely. With the clinical picture involving a recent diagnosis of HIV as well as a diarrheal illness in addition to negative infectious and crystallopathy work up, a diagnosis of reactive arthritis was made.
Some Notable Labs:
Wrist Synovial Fluid:
(H) 96,000 leukocytes/cumm
(H) 92 % PMNs
Gram stain and culture negative
Right sided supra patellar effusion, otherwise normal X-rays.
Morning Report Pearls:
Though cases do not always fit the classic presentation, it can be useful to breakdown etiologies of joint complaints by the number involved.
Oligoarthritis (2-4 joints) Differential
Polyarthritis (>5 joints) Differential
|1. Acute Infection: Bacterial
2. Subacute/Chronic Infection: Fungal, TB, Lyme
3. Crystal Disease: CPPD, Gout
6. Monoarticular Rheumatoid Arthritis
|1. Spondyloarthropathies: AS, Psoriatic arthritis, Reactive arthritis, IBD
2. Disseminated Gonococcal
3. Rheumatic Fever
4. Lyme Disease
|1. Chronic inflammatory: Rheumatoid arthritis, SLE, Psoriatic, Vasculitis
2. Acute Viral: Hepatitis, Parvo, Rubella, HIV, Enterovirus
3. Drug Induced Serum Sickness
Synovial Fluids Studies are important in differentiating non-inflammatory conditions from inflammatory. Also the degree of leukocyte elevation can provide useful information for determining an etiology.
Synovial Fluid Leukocyte Count:
<200 = Normal
200-2,000 = Non-Inflammatory
2,000 = Inflammatory
50,000 = High Concern for Septic Joint however Crystal Disease, Reactive Arthritis and other autoimmune disorders like Rheumatoid Arthritis can not be completely excluded
Mildly elevated Rheumatoid Factor occurs in the general healthy population and also be positive in certain infections and/or autoimmune conditions. RF is very sensitive for the diagnosis of Rheumatoid Arthritis but that means it can include a higher number of false positives so mildly elevated results in the incorrect clinical picture needs to be scrutinized. The fact that Anti-CCP is negative, a specific test, makes RA diagnosis less likely in this case as well.