Classification of Arthritis

Classification

Characteristic features

Seropositive rheumatic diseases

1. Connective tissue diseases

• Rheumatoid arthritis (RA)

• Systemic lupus erythematosus (SLE)

• Antiphospholipid antibody syndrome (APS)

• Scleroderma/progressive systemic sclerosis (PSS)

• Polymyositis/dematomyositis (PMY/DMY)

• Mixed connective tissue disease

• Sjogren’s syndrome

• Skin: Nodules, ulceration, rash, mucosal ulcers

• Raynaud’s phenomenon

• Sicca syndrome

• Neurological involvement

• Renal involvement

• Vascular involvement

• Positive serology

• Constitutionally unwell

2. Vasculitides

• Polyarteritis nodosa (PAN)

• Wegener’s granulomatosis

• Predominantly cutaneous vasculitis

• Giant cell arteritis

Seronegative rheumatic diseases

• Ankylosing spondylitis (SA)

• Reactive arthritis

• Psoriatic arthritis

• Inflammatory bowel disease

• Involvement of axial skeletal

• Anterior uveitis, conjunctivitis

• Enthesitis, sacroiliitis, dactylitis, urethritis

• Psoriasis

• Family history

• HLA-B27 association

Crystal induced

• Gout (monosodium urate)

• Pseudogout (calcium pyrophosphate dihydrate)

• Hydroxyapatite deposition disease

• Remitting, recurring pain

• Mono or oligoarthritis

• Tophi

• Renal involvement

Septic/infectious

• Acute monoarthritis or migratory polyarthritis

• Constitutional symptoms

Degenerative

• Insidious onset

Non-articular rheumatism

• Generalised non-articular pain

• Trigger points 

• Strong association with psychiatric illness

Monoarticular

Polyarticular (more than 4 joints)

Oligo-arthritis (2-4 joints)

(Mnemonic: SINGL JOINT)

• Septic Arthritis (most important to rule-out)

1. 1. 1. Bacterial / Fungal / Parasitic Arthritis
      2. Gonococcal Arthritis (esp. young sexually active adults)
      3. Mycobacteria

• Internal derangement or Trauma

1. 1. 1. Meniscus Injury
      2. Ligament tears
      3. Overuse syndromes

• Inflammatory Arthritis – Aseptic (Reactive Arthritis)
• Neuropathy (Charcot’s Joint)
• Gout, Pseudogout
• Trauma

1. 1. Overuse injury
   2. Fractures
   3. Hemarthrosis
2. Juvenile or adult Rheumatoid Arthritis
3. Osteoarthritis
4. Osteomyelitis
5. Ischemic bone (avascular necrosis)
6. Neoplasms
   1. Osteoid Osteoma
   2. Pigmented Villonodular synovitis
   3. Bony metastases

    Large joints

        Ankylosing Spondylitis

    Small joints

        Parvovirus B19

        Systemic Lupus Erythematosus

    Large and small joints

        Osteoarthritis

        Rheumatoid Arthritis

        Psoriatic Arthritis

1. Viral Infection

• Parvovirus B19, EBV, VZV, Enterovirus, Adenovirus or Coxsackievirus, Hepatitis, HIV, Mumps, Rubella

1. Bacterial Infection

• Gonococcal Arthritis
• Bacterial Endocarditis
• Rheumatic Fever
• Salmonella, Shigella or Yersinia 
• Staphylococcus aureus
• Tuberculosis
• Lyme Disease
• Syphilis

1. Inflammatory disease 

• Sjogren’s Syndrome
• Ankylosing Spondylitis
• Reiter’s Syndrome
• Psoriatic Arthritis
• Inflammatory Bowel Disease
• Rheumatoid Arthritis
• Systemic Lupus Erythematosus 

1. Systemic conditions 

• Polymyositis
• Polymyalgia Rheumatica
• Sarcoidosis/Scleroderma
• Henoch-Schonlein Purpura
• Polyarteritis Nodosa
• Wegener’s Granulomatosis
• Hyper/Hypothyroidism
• Hyperparathyroidism

1. Miscellaneous

• Fibromyalgia
• Osteoarthritis 
• Cancer (Multiple Myeloma, Metastatic Cancer)
• Crystal-induced (e.g. Gout, Pseudogout)

• Oligoarticular JIA
  Reactive arthritis 
• Psoriatic Arthritis

Modality

Advantages

Disadvantages

Clinical utility

Plain film

High resolution, inexpensive

Inadequate soft tissue images, radiation exposure

Bone pathology

CT

Better in complex joints

Radiation, suboptimal for detecting soft tissue pathology, cost

Sacroiliac joints, ankle joints, spinal canal, chest

MRI

No radiation, best for soft tissue pathology, effusions, abscesses, avascular necrosis

Cost, potential for patient injury from metallic objects, contrast allergy

Evaluation of tendons, bursae, effusions, ligament, muscle, spinal canal

U/S

No radiation, cheap

Resolution decreases with deeper structures, dependent on operator

Evaluation of rotator cuff injury, tendons, bursae, effusions

Bone densitometry

Relatively low radiation

Osteoporosis

Angiography

Ideal for vascular pathology

Radiation exposure, contrast allergy, emboli risk

Inflammatory disorders with vascular components

Scintillography (bone scan)

Sensitive for metabolic processes

Low resolution, non-specific

Septic joints, fractures, cancer