Monoarticular rheumatoid arthritis of the wrist: a rare entity

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SCIENCE
Monoarticular rheumatoid arthritis of the wrist: a rare entity

A 70-year-old male patient presented to our outpatient clinic with complaints of pain in the left wrist during the previous 6 months and restriction of wrist movements for 4 months. On examination, he had diffuse swelling of his left wrist. There was no warmth and joint-line tenderness was present. Dorsiflexion and palmar flexion were restricted to 40 degrees and 20 degrees, respectively. Abduction and adduction were restricted by 10 degrees when compared with the right wrist. His metacarpophalangeal and proximal interphalangeal joints were normal. His spine was clinically uninvolved. No skin lesions were detected.

Radiographs showed lytic lesions in distal radius and carpal bones, concentric reduction of wrist joint space and periarticular osteoporosis. Erythrocyte sedimentation rate and C-reactive protein were elevated. Rheumatoid factor was negative. Uric acid levels were normal. Joint aspirate culture was negative. Anti-citrullinated cyclic peptide was strongly positive.

The most likely diagnosis of this patient is

  • Gout
  • Osteoarthritis
  • Carpal Tunnel Syndrome
  • Rheumatoid Arthritis

Introduction

Rheumatoid arthritis (RA) has a varied clinical presentation, but an insidious onset of pain with symmetric swelling of small joints of the hand is the most frequent finding. The patterns of presentation include palindromic onset, monoarthritis, extra-articular synovitis (tenosynovitis, bursitis), polymyalgia-like onset and general symptoms.1 Monoarticular RA is an infrequent clinical presentation and it usually occurs in the hips and knees. The purpose of this case report is to keep RA in the differential diagnosis of monoarthritis and to use anti-citrullinated cyclic peptide (CCP) assay more regularly to diagnose RA.

Medical History

He had no history of fever or trauma to that wrist. There was no involvement of other large joints in the body or pain or restriction of movements in the small joints of both hands. He denied history of weight loss or cough with sputum and there was no contact with tuberculosis.

Examination

Radiographs of the left wrist and hand revealed lytic lesions in the distal radius and the carpal bones. There was subchondral sclerosis at the distal radius with concentric reduction in wrist joint space. Periarticular osteoporosis was evident. Total leukocyte count and uric acid levels were within normal range. Erythrocyte sedimentation rate was high (36 mm) and C-reactive protein was positive (24 mg/L). RF was negative.

Mantoux skin test was performed to rule out tuberculous monoarthritis of the wrist, which was negative. CT scan showed lytic lesions in distal radius and carpal bones with synovial thickening. Microscopy of the synovial fluid to detect crystals was negative. Open biopsy of the left wrist was inconclusive. A working diagnosis of monoarticular RA was made as a diagnosis of exclusion and anti–CCP antibody assay was done. The test showed a strong positive value of 115.23 μ/ml.

Management

The patient was put on disease-modifying anti-rheumatic drugs (DMARD). Patient showed good symptomatic relief in 2 months following the medical treatment.

Discussion

The common causes of monoarthritis are infection, trauma, crystal deposition disorders (gout and pseudogout), psoriasis, RA and neoplasm (pigmented villonodular synovitis). The onset of most of these conditions is often acute and dramatic with fever, pain and swelling of the joint.2  RA affects 1% of the world population.3 RA is characterized by chronic inflammation of synovial joints with progressive erosions and joint destruction. Any joint can be involved in RA (even the cricoarytenoid joint), but the preferential sites are the proximal interphalangeal and the metacarpophalangeal joints of the hand as well as the metatarsophalangeal joints of the foot, the knee and the joints of the upper limb.4 Monoarthritis due to RA is quite rare and often involves the hips and the knees.  RF anIgM antibody directed against the constant portion of IgG antibody is present in 70-80% of patients with RA. RF is absent in 15-20% of patients with RA.5  Anti-CCP is useful in differentiating RA from other disorders that may present with arthritis. Citrulline is an unusual autoantibody formed by post-translational modification of arginine residues. Autoantibodies to citrullinated proteins such as filaggrin and its circular form are found in RA. Synthetic CCP variants react with anti-filaggrin  autoantibodies and serve as substrate for detecting anti-CCP antibodies serologically.6   The sensitivity of anti-CCP is about 74% and the specificity is 96- 98%, as compared to RF whose sensitivity and specificity are 69.7- 81% respectively.

Learning

Our case did not have the classical features of RA. Monoarticular presentation of RA is rare, of which isolated wrist involvement is even rarer. It should be considered in the differential diagnosis of monoarticular arthritis, and anticitrullinated cyclic peptide should be used more frequently to diagnose rheumatoid arthritis in doubtful cases.

Reference

  1. Grassi W, De Angelis R, Lamanna G, Cervini C. The clinical features of rheumatoid arthritis. Eur J Radiol. 1998 May;27(Suppl 1):S18–24.
  2. Scutellari PN, Orzincolo C, Castaldi G, Franceschini F. Monoarthritis. Radiol Med. 1995 Dec;90(6):689–98.
  3. Khosla P, Shankar S, Duggal L. AntiCCP antibodies in rheumatoid arthritis. J Indian Rheumatol Assoc. 2004;12:143–6.
  4. Scutellari PN, Orzincolo C. Rheumatoid arthritis: sequences. Eur J Radiol. 1998 May;27(Suppl 1):S31–38.
  5. Swedler W, Wallman J, Froelich CJ, Teodorescu M. Routine measurement of IgM, IgG, and IgA rheumatoid factors: high sensitivity, specificity, and predictive value for rheumatoid arthritis. J Rheumatol. 1997 June;24(6):1037–44.
  6. Mimori T. Clinical signiϐicance of antiCCP antibodies in rheumatoid arthritis. Intern Med. 2005 Nov;44(11):1122–6.
  7. Sauerland U, Becker H, Seidel M, Schotte H, Willeke P, Schorat A, et al. Clinical utility of the anti-CCP assay: experiences with 700 patients. Ann N Y Acad Sci. 2005 Jun;1050:314–8
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