Psoriatic And Reactive Arthritis

Classified under peripheral spondylarthritis- it is Upper Limb> Lower limb. Characteristic involvement- small joint> large joint. 5-30% of psoriasis patients develop Psoriatic arthritis. Usually more severe and mutilating than RA.

Epidemiology 

• Males are more affected than females. Majority are between 30-55 yrs. 30% have family history. Concordance rate: Psoriasis: 30-70% and Psoriatic Arthritis: 10-30%.

Genetics 

• HLA Cw0602: Psoriasis, HLA-B27: 50-70% with axial joint involvement are positive(Higher risk)- <20% with peripheral, HLA-B39, HLA-DR7, HLA-DR3, HLA-B38, HLA-B08, Non HLA loci- TNIp1, IL23R, TNFAIP3.

Clinical features 

• 2/3rd only have psoriasis. 15% develop Psoriasis and Psoriatic arthritis within 12 months, remaining Psoriatic arthritis precedes with skin changes.

Skeletal Manifestations 

• 5 distinct types of joint involvement- DIP arthritis: 15% of patients, Asymmetric. Oligoarthritis: Most common type in psoriasis patients. Symmetric RA like arthritis: 40%. Spondylitis: 20% and Arthritis stimulants: 5%. Joints typically involved DIP, Temporomandibular joint and Manubriosternal joint

Extra-articular Manifestations 

• Nail Changes: In most of patients almost 100%. Pitting of nails- More than 20 pits per nail. Onycholysis: Yellow discoloration, Hyperkeratosis. Ocular: Uveitis anterior: Most common posterior, bilateral and chronic. Aorta: Aortitis, Aortic regurgitation.

Evaluation 

• ESR and CRP elevated: Severe forms associated with hyperuricemia. 10% may have anti-CCP antibodies.

Radiological Features 

• Pencil cup deformity: Marginal Erosions with adjacent bony proliferation- Whiskering of joints.

Small Joint Ankylosis:

Arthritis Mutilans: Telescoping fingers

Ray pattern of Joint involvement: Not common. Involvement of all or adjacent joints. Ivory Phalanx.

Axial Involvement: Asymmetric sacroiliitis. Syndesmophytes- Marginal: Characteristic. Non marginal: Characteristic- Asymmetric, bulky , Less delicate.

Diagnosis 

• Clinical- CASPAR criteria- Specificity 99%, Sensitivity 91%, Inflammatory articular disease >= 3 points mentioned. Current Psoriasis(2)/ personal history of psoriasis(1) or family history(1), Typical psoriatic nail dystrophy on current examination(1), Negative RA factor(1), Current Dactylitis or history of Dactylitis documented by Rheumatologist. Radiography evidence of extra articular new bone formation.

Management 

Skin and Joint disorders: therapy should be directed. NSAIDS. Anti TNF : Mainstay. Ustekinumab- Anti IL12/23. Secukinumab- Anti-IL17A. Apremilast(PDE4#)- Not for radiologically evident joint damage/ axial involvement, a relatively safer method. Leflunomide.

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Reactive Arthritis

• It’s a non-purulent oligo/polyarthritis caused as a consequence of infection elsewhere in the body either by Enteric infection, Genitourinary or rare instance involve URTI.

Etiology 

• Most triggering agents are gram negative bacteria . Enteric Infections: Salmonella, Yersinia enterocolitica, Shigella: Most common in India(Dysenteriae). Sonnei, Flexneri. Genitourinary infections: Chlamydia Trachomatis.

Pathogenesis 

• Not well established. Higher risk features- HLA B27: Half of the patients, ERAP1, IL23R.

Epidemiology 

• Male: female=1 following enteric information. M>F : Following genitourinary infections. HLA B27 almost = 50% of patients. Africans are usually negative for HLA B27 but majority are HIV positive. Strongest association- Shigella, Yersinia, Chlamydia. Weak Association- Campylobacter.

Articular Manifestations 

• Latency between infections: 1- 3 or 4 weeks, present with abrupt onset. Asymmetrical Oligoarthritis- Lower Limb> Upper Limb. Enthesitis- Achilles Tendinitis, Plantar Fascitis. 
• Dactylitis- Sausage Digits, Dactylitis.

• Fusiform Swelling: Seen in various other conditions.

• Achilles Tendinitis

Extra Articular Manifestations 

• Ocular- Conjunctivitis, Anterior Uveitis: Can be recurrent and alternative. Skin- Keratoderma Blennorrhagica. Pustules: Hyperkeratotic lesions: Psoriasiform lesions on palms and soles.

• Nail Changes- Onycholysis, distal yellowish, pitting and heaped up hyperkeratosis.

• Glans- Circinate Balanitis, pustules. lesions are painless.

Natural Course 

• 1/3rd single: recovery 3-6 months. 2/3rd Chronic > 6 months. Risk Factors- HLA B27+ and Shigella.

Diagnosis 

• Clinical- Berlin Criteria and Brown Criteria.

Brown Criteria Classification

Major criteria

• Arthritis with 2 of 3 of the following findings. · Asymmetric- · Mono-or oligoarthritis, affection predominantly in lower limbs
• Preceding symptomatic infection, with 1 or 2 or the following findings- Enteritis (diarrhoea for at least 1 day, 3 days to 6 weeks before the onset of arthritis). · Urethritis (dysuria or discharge for at least 1 day. 3 days to 6 weeks before the onset of arthritis).

Natural Course 

• 1/3rd single: recovery 3-6 months. 2/3rd Chronic > 6 months. Risk Factors- HLA B27+ and Shigella.

Diagnosis 

• Clinical- Berlin Criteria and Brown Criteria.

Brown Criteria Classification

Major criteria

• Arthritis with 2 of 3 of the following findings. · Asymmetric- · Mono-or oligoarthritis, affection predominantly in lower limbs.
• Preceding symptomatic infection, with 1 or 2 or the following findings- Enteritis (diarrhoea for at least 1 day, 3 days to 6 weeks before the onset of arthritis). · Urethritis (dysuria or discharge for at least 1 day. 3 days to 6 weeks before the onset of arthritis).

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Hope you found this blog helpful for your NEET SS Rheumatology Preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.