Reactive Arthritis- Etiology, Diagnosis And Treatment

Non-purulent oligo/polyarthritis resulting from infection elsewhere in the body; Infection of the enteric tract; Genitourinary; In rare cases: Involve URTI.

Etiology

Gram negative bacteria represent the majority of triggering factors.
Salmonella, Yersinia enterocolitica, Sonnei, Flexneri, Shigella: most prevalent in India, and genitourinary diseases, including Chlamydia Trachomatis.

Pathogenesis

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

Epidemiology 

HLA B27 almost = 50% of patients; Male: Female = 1 following intestinal information; M>F: Following genitourinary infections; The majority of Africans are HIV positive but typically negative for HLA B27.
Campylobacter, Shigella, Yersinia, and Chlamydia have the weakest associations.

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
    • Palms 
    • Soles

• Nail Changes
  • Onycholysis
  • Distal Yellowish
  • Pitting 
  • Heaped up hyperkeratosis

• Glans
• Circinate Balanitis
• Pustules
• Lesions are painless

Natural Course

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

Diagnosis

• Clinical
  • Berlin Criteria
  • Brown Criteria

Also Read: Antiphospholipid Syndrome (APS)

Brown Criteria Classification

Major criteria 

1. Arthritis with two out of the three results listed below
Asymmetric; Oligoarthritis or monoarthritis;  Predominantly lower limb affection.
2. Ahead of the onset of symptoms, with one or both of the subsequent observations - Urethritis (dysuria or discharge for at least one day) • Enteritis (diarrhea for at least one day, three days to six weeks prior to the development of arthritis). Three to six weeks prior to the development of arthritis) 
Little requirements, at least one of the following:

Proof of an infection-triggering agent -  Positive nucleic acid amplification test for Chlamydia trachomatis in the morning pee or urethra/cervical swab; Positive stool culture for enteric infections linked to ReA.

Definition of reactive arthritis:  Probable ReA: Meets both major and pertinent minor criteria • Definite ReA: Meets both major and minor criteria. Probable ReA:

1. Both Major Criteria, but no relevant minor criteria or 
2. Major criteria 1 and one or more of minor criteria 

Also Read: Rheumatoid Arthritis

Treatment

Promptly identify enteritis/Urethritis

• Antibiotics
  • Controversial
  • Benefits shown if Rifampicin given for 6 months for Chlamydia
• Acute
  • DOC: NSAID
  • Indomethacin
  • 75-150 mg per day
• Chronic: 
  • DOC: Sulfasalazine
  • 2-3 gms per day
• Refractory
  • AZA
  • MTx
  • Anti TNF 

Also Read: Aortic Aneurysm- Thoracic And Abdominal Aortic Aneurysm

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