Rheumatoid Arthritis 

Before I begin, just thought I’d let it be known that I spilt a patient’s cup of water over their table- again! Well, last time it was the entire jug, so I must be making progress…

That aside, I saw a patient with quite severe rheumatoid arthritis today. She was in for diarrhoea and vomiting.

She had very swollen joints, particularly her metacarpophalangeal joints. Distal interphalalangeal joints were spared. She had the classic Z shaped thumb and there was ulnar deviation of her fingers. Her knees were swollen and she had a valgus deformity, greater on the left. She had some vitiligo. Joints were very tender and it was painful for her to get out of bed to stand up.


Rheumatoid Arthritis

Definition: rheumatoid arthritis (RA) is a chronic symmetrical deforming poly-arthritis (joint inflammation), which is a systemic autoimmune disease associated with extra-articular involvement.

Aetiology/ risk factors: Cause unknown

-Risk factors: family history, HLA-DR4, HLA-DR1, prevalence higher in smokers

 

Epidemiology: affects 0.5-3% of the population worldwide

-peak prevalence 30-50 years

-3x more women affected pre-menopause and equal incidence after

 

-RA is characterised by synovitis- inflammation of the synovial lining of joints, tendon sheaths or bursae.

-There is an inflammatory process within the synovium, thought to be initiated by the activation of synovial T cells and involving inflammatory cell infiltration,  macrophage stimulation, cytokines, chemokines, autoantibody production and immune complex formation. There is also new synovial blood vessel generation and proliferation of the synovium, growing over the cartilage of joints, producing a mass called a pannus, which destroys the cartilage and the bone below (subchondral), producing bony erosions.

Image result for rheumatoid arthritis pannus

Symptoms: 

-typically insidious onset pain (less commonly: ‘explosive’-sudden onset of widespread arthritis, panlindromic- relapsing and remitting monoarthritis of different large joints- or systemic illness with few joint symptoms initially.)

-early morning stiffness lasting > 30 mins (following a football session in inappropriate footwear, my ankles hurt a lot on my walk to the tube station, more in the mornings than in the afternoons leading me to consider this diagnosis. Fortunately, the pain has since subsided)

-symmetrical swelling, pain and stiffness in the small joints of the hands and feet

-Extra-articular: fever, fatigue, weight loss (less common)

 

Signs:

-warm, tender joints and reduction in range of movement
-spindling of fingers caused by swelling of the proximal but not distal interphalangeal joints. Metacarpo-phalangeal and wrist joints are also swollen.

eventually many joins are involved, iImage result for hand deformities in rheumatoid arthritisncluding: wrists, elbows, shoulders, cervical spine, knees, ankles, feet. Thoracic and lumbar spine are not involved.

-joint effusions and wasting of muscles around the affected joints are early features

-as disease progresses: weakening of joint capsules ⇒ joint instability ⇒ subluxation (partial dislocation) ⇒ deformity

-characteristic hand deformities: ulnar deviation of fingers (MCP joint subluxation) Z thumb, swan neck deformity, Boutonnière’s deformity,  (these tend to occur in late RA, if not controlled properly), radial deviation of wrist

 

-Extra-articular manifestations:

 

-bursitis

-tenosynovitis

-subcutaneous nodules (20% cases)

-usually over pressure points, typically extensor surface of ulna, finger joints, Achilles tendon. Patients with nodules are usually seropositive (i.e. have circulating rheumatoid factor)   -can occur in lungs

-Carpal tunnel syndrome

-Lymphadenopathy

-Secondary Sjögren’s syndrome (autoimmune disease of moisture producing glands = dry mouth and eyes)

-Anaemia, thrombocytosis

And many more random, less common manifestations across the body, including: vasculitis, fibrosing alveolitis, pleural and pericardial effusion, Raynaud’s, peripheral nephropathy, amyloidosis, etc.

   -There is increased risk of infection, osteoporosis, cardiovascular disease

Investigations:

-RA diagnosis usually made clinically.

Bloods: normochromic, normocytic anaemia (of chronic disease) and thrombocytosis.

ESR and CRP raised in proportion to activity of the inflammatory process.

Serum antibodies: 

-Anti-citrulline-containing peptide (anti-CCP)- high specificity- 98%- and sensitivity for RA

-Rheumatoid factor– +ve in 70%,  not specific, occurs in connective tissue diseases & some infection

-Antinuclear antibody- +ve in 30%

Radiology- affected joints show soft tissue swelling in early disease and later joint narrowing, erosions at the joint margins and porosis of periarticular bone and cysts, and may have subluxation or complete carpal destruction

Synovial fluid- sterile with high neutrophil count (joint aspiration to exclude septic arthritis acutely)

References: Kumar & Clark’s, Cheese and onion, Rapid Medicine

PS: I had a look in her notes, and it turns out she has ‘seronegative non-erosive arthropathy’, though when we asked her, she said she had RA. Rheumatology is a bit confusing in that rather than specific diseases, there is a sort of spectrum, with diseases bleeding into each other. She definitely had classic RA hands.

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