Approach to Joint Pain - Arthritis Differential Diagnosis Framework



Inflammatory Versus Noninflammatory Pain

 • Is it inflammatory vs noninflammatory?

 • Inflammation is suggested by warmth, effusion, erythema and WBC >2000 in synovial fluid

 • What is the time course (acute/subacute/chronic)?

 • How many joints are involved (monoarthritis, oligoarthritis, polyarthritis)?

 • Distribution - peripheral vs axial (spine, shoulders, hips)?

 • Is it symmetric?

 • Is there a pattern (additive vs migratory vs intermittent)?



Autoimmune → Inflammation

Mechanical/degenerative disorders → noninflammatory

Signs of inflammation are:

 • Pain

 • Erythema

 • Soft tissue swelling

 • Warmth

 • Noninflammatory

 • Pain, stiffness < 30 mins

 • Pain worse with activity

 • Painful, stiff, stiffness after non-activity, may have effusion with few WBCs (200-2000/µL)

 • No constitutional symptoms



Inflammation →

 • Morning stiffness lasting > 30 mins - 1 hour

 • Very hard to get out of bed, better after taking a shower and moving around in the morning

 • Effusion leukocyte count > 2000/µL

 • Better with activity

 • Better with NSAIDs

 • Waking up with pain at night



Pain with passive range of motion → articular condition

Pain with active range of motion → periarticular condition



MONOARTHRITIS

• Acute Monoarthritis:

	- Noninflammatory

		• Trauma

		• Hemarthrosis

		• Internal derangement/Avascular necrosis

	- Inflammatory

		• Crystal induced (Gout/Pseudogout)

		• Infectious (Gonococcal/Lyme etc)

• Chronic Inflammatory Monoarthritis (>6 weeks) Can Be Caused By:

	- Chronic Infection

		• Mycobacterial

		• Fungal

		• Borrelia burgdorferi

		• Virus/Bacteria

		• Syphilis

	- Autoimmune Rheumatologic Disease



OLIGOARTHRITIS

• 2-4 joints

• Typically in an asymmetric pattern

Acute Inflammatory Oligoarthritis:

	• Gonorrhea

	• Rheumatic fever

	• Lyme

	• Gout/Pseudogout

Chronic Inflammatory Oligoarthritis:

	• Autoimmune conditions such as spondyloarthritis



POLYARTHRITIS

• 5 or more joints

Viral Infections:

	• Parvovirus B19

	• HIV

	• Hepatitis B virus

	• Rubella

Bacterial Infection:

	• Neisseria gonorrhoeae (gonorrhea)

	• Bacterial endocarditis

	• Campylobacter species

	• Chlamydia species

	• Salmonella species

	• Shigella species

	• Yersinia species

	• Tropheryma whippleii (Whipple's disease)

	• Group A streptococci (rheumatic fever)

	• Staphylococcus aureus

	• Gram-negative bacilli

	• Borrelia burgdorferi (Lyme disease)

	• Mycobacterium tuberculosis (tuberculosis)

	• Fungi, secondary syphilis

Chronic Inflammatory Polyarthritis (>6 weeks in duration):

	• Rheumatoid arthritis

	• SLE

	• Psoriatic arthritis

	• Adult onset Still's

	• Ankylosing Spondylitis, IBD



Symmetrical:

	• RA

	• SLE

Asymmetrical:

	• Psoriatic arthritis

	• Reactive arthritis

	• Lyme arthritis



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