Reactive Arthritis

Question 1

Define reactive arthritis.

Answer 1

Sterile arthritis occurring after an extra-articular infection (commonly GI or urogenital)

Reiter’s syndrome is associated with this but only found in a minority of cases.

Question 2

What is Reiter’s syndrome?

Answer 2

A triad of reactive arthritis, urethritis and conjunctivitis.

Question 3

What are the risk factors for reactive arthritis?

Answer 3

• Male sex - 9:1 ratio in incidence of chlamydia-induced reactive arthritis. Post-dysentery ReA is M:F 1:1.
• HLA-B27 genotype - in 30-50%
• Preceding chlamydial or GI infection

Question 4

What are the symptoms of ReA? How quickly do they develop?

Answer 4

Symptoms develop 3-30 days after infection

Symptoms of:

• Fatigue, fever, weight loss
• burning or stinging on passing water (urethritis),
• arthritis,
• low back pain (sacroilitis),
• painful heels (enthesitis, plantar fasciitis)
• conjunctivitis

Question 5

What are the signs of reactive arthritis on examination?

Answer 5

Enthesitis - inflammation at sites where tendons insert into bones including Achilles’ tendon and plantar fascia at the calcaneus –> heel pain

Skin rash- keratoderma blennorrhagicum (10%) undistinguishable from pustular psoriasis, brownish-red macules, vesicopustules and yellowish brown scales on soles or palms

Circinate balanitis - painless ulcers on shaft/glans of penis, scaling red patches

Oral ulceration - usually painless

Ocular - conjunctivitis causing redness, tearing and sterile purulent discharge; or iritis (anterior uveitis) causing pain, redness, photophobia and assoc with HLA-B27

Cardiac - aortitis –> aortic regurgitation, precipitating HF; arrhythmias secondary to scarring of conduction system by chronic inflammation.

Other: fever, nail dystrophy, hyperkeratosis, onycholysis.

Question 6

Which joints are affected by reactive arthritis? Is it symmetrical?

Answer 6

Asymmetric oligoarthritis

Lower extremities, sausage shaped digits

Question 7

What investigations would you do for reactive arthritis?

Answer 7

Bloods:

• FBC - anaemia can indicate systemic illness
• ESR/CRP - raised
• HLA-B27 testing if unsure
• ANA/rheumatoid factor - negative - to rule out other forms

Stool/urethral:

• Urogenital and stool cultures - may be negative by the time arthritis develops
• Urine - screen for chlamydia trachomatis

Joint:

• Plain X Ray - chronic cases; erosions at entheses (e.g. Achilles’ tendon, plantar spurs), sacroilitis, spinal disease with asymmetrical syndesmophytes.
• Joint aspiration - exclude septic or crystal associated arthritis