35 male. Professional martial arts instructor. Has noticed progressive joint swelling in his hands.

The differential diagnosis includes what main categories?

1. Inflammatory (seropositive & seroneg active)
2. Non-inflammatory (OA)
3. Infection (long list)
4. Crystal (gout & pseudo gout)

With these four categories in mind, what history would be pertinent?

1. INFLAMMATORY – worse in the morning and gets better as the day progresses. Symmetric & bilateral polyarthritis sparing DIPs in seropositive (RA, SLE, other CTD). Asymmetric and more commonly oligoarthritis for seronegative (psoriasis, IBD, anykylosing spondylitis, reactive). RA has many extraarticular features.

2. NON-INFLAMMATORY – Gets worse with activity as the day progresses. Affects joints frequently used or joints that have been injured in past (knees, PIPs, DIPs and 1st CMC).

3. CRYSTAL – Joints can be swollen. Tophi are an important clue for gout. Occurs more commonly in patients with hypertension, obesity and renal disease.

4. SEPTIC – Fevers, chills and sweats. Commonly a single red, hot and swollen joint. Less commonly a polyarthritis. Involvement of prosthetic joints is important because the organism is usually different and will require alternative antibiotic coverage.

What is the difference between polyarticular vs. pauciarticular vs. monoarticular arthritis?
 Identifying polyarticular vs. pauciarticular vs. monoarticular on history/physical will shift the focus within the differential diagnosis. It is a good starting point on history. The number of joints involved and pattern of joint involvement can narrow differential.

Polyarticular arthritis refers to multiple joints involved and can be multiple similar joints (e.g. multiple PIPs) or a combination of different types of joints (e.g. PIPs/MCPs/Knees/etc). >= 5 joints by one definition.

Pauciarticular refers to a few joints are usually includes larger joints like the knees.

Monoarticular refers to a single joint.

Update 1: History

Not worse in the morning. Has difficulty using his hands all day. Now works as a sculpture and is severely limited. The arthritis in his hands has been present for 2 years now but although mild in the first year it has escalated with increasing deformity over the 2nd year. MTPs and DIPs seem to be the worst. In addition his wrists, elbows, knees and ankles are involved. No fevers, chills or night sweats.

Not obese. Does not smoke or drink or use recreational drugs.

Was healthy other than the arthritis. Had a high BP a few times at yearly medicals but doesn’t recall them being very high.

Family history is significant for diabetes, hypertension and kidney disease.

ROS significant for nodules over knees and some MTPs.

With these four categories in mind, what physical exam would be pertinent?

Determine if pain is articular and/or extra-articular (bursitis, tendinitis, muscle sprain). Extra-articular pathologies may retain passive ROM with limited active ROM.

Vitals – Febrile patient may have inflammatory, crystal, or septic arthritis

1. INFLAMMATORY – assess for synovial hypertrophy, synovitis (soft tissue swelling, joint warmth/effusion, and decreased ROM), subcutaneous nodules, joint deformity, psoriasis. Asses for uveitis, conjunctivitis, episcleritis. Asses axial spinal tenderness & ROM. Asses for splenomegaly.

2. NON-INFLAMMATORY – bony enlargement & deformity, joint line tenderness, crepitus, limited ROM, periarticular msk atrophy.

3. CRYSTAL – severe joint pain, swelling, erythemia. Tophi may be present.

4. SEPTIC – red, hot, swollen joint, may be unable to bear weight. Assess for pustule & vesicle skin lesions.

Update 2: Physical

Joint swelling is localized to most MTPs and some PIPs and DIPs in addition to wrists, elbows, knees, ankles and 1st MTPs. Many of the joints are hot and tender with nodular swellings. No extraarticular features of CTD.

No periarticular swelling or tenosynovitis. No rashes. No psoriatic skin/nail changes. Back ROM normal.

Nodular swellings over MTPs are quite severe with a few breaking down and leaking white chalky material. Few white nodules on ear lobes as well.

Afebrile. No track marks.

How would you workout these four categories?

Seropositive – RF, ANA, C3, C4, ENA, X-ray (erosions, periarticular osteopenia)
Seronegative – HLA B27, X-ray (spine and SI joint)

2. NON-INFLAMMATROY  (Osteoarthritis)
X-ray (Bouchard’s, Heberden’s, joint space narrowing)

Gout – Joint aspiration with cell count/culture for red-hot-swollen joints, serum uric acid, creatinine, x-ray (tophi, destructive erosions with overhanging margins)

Pseudogout – corrected serum calcium/PTH (hyperparathyroidism), serum magnesium (hypomagnesemia), serum phosphate (hypophosphatemia), TSH (hypothyroidism), serum ferritin (hemochromatosis), x-ray (chondrocalcinosis, osteoarthritis)

4. SEPTICJoint aspiration with cell count/culture for red-hot-swollen joints

Update 3: Investigations

Inflammatory – negative RF and ANA. C3/C4 normal. x-rays of back/SI joint normal

Non-inflammatory – no OA changes on x-rays

Crystal – serum uric acid 567 micromol/L, x-ray (tophi, destructive erosions of DIPs with overhanging margins)

Copy of relevant X-Ray avalable here: