Thanks to Alex for presenting a great case of a middle aged woman with oligo/polyarthritis, ultimately diagnosed with disseminated gonococcus!
Polyarthritis can be a challenging complaint to parse through.
Important questions to ask
- Timing (acute = <6 weeks)
- Inflammatory or not (swelling suggests inflammatory)
- This is not necessarily an exact science; a patient with mostly inflamed MCPs and a single DIP on one side and the converse on the other hand would still be considered symmetric
- Large vs small joints
- Ex: Lyme often presents with an acute monoarthritis, commonly in the knee; small joints are uncommon
- History of crystal arthritis
- Older patients are more likely to p/w CPPD/pseudogout
- Things that predispose to high uric acid
- EtOH use
- NSAID responsiveness
On exam, make sure to look for:
- Joint exam
- Tophi (found particularly in the olecranon bursa and in fingertips- they can be very subtle!)
- Gout tophi tend to be right in the olecranon, whereas rheumatoid nodules tend to be a little distal to the olecranon
Check out this calculator which may help you think about how likely gout is in your patient.
We talked briefly about the ANA.
The ANA is not a standardized test from lab to lab.
- One lab might be different than another
- So positivity depends on where it’s being tested, so 1:80 might be considered positive in one place and negative somewhere else
- In one study, up to 20% of patients have a low level positive ANA
- Some labs will use an ELISA for the ANA, for which the result will just be a number (not a titer)
The patient was ultimately diagnosed with disseminated gonococcus, with a synovial WBC count of 96000- this is unusual because gonorrhea usually causes a WBC count <50000!
- Tx: ceftriaxone x 2 weeks + azithromycin
- Also consider doing a surgical washout of the affected joint, particularly if it’s weight bearing; this may allow the patient to return to weight-bearing status more quickly!