Page 612 - Concise Pathology for Exam Preparation ( PDFDrive )

21 Musculoskeletal System 597

• Osteoclastic activity in underlying bone
• Pannus formation (pannus is a combination of neovascularization, inflammation
and fibrinoid deposits, which progressively destroys the underlying cartilage and
subchondral bone)

X-Ray
• Joint effusion
• Juxta-articular osteopenia with bone erosions and narrowing of joint spaces due to loss
of articular cartilage

Diagnosis
At least four of the following should be present for the diagnosis of RA:
• Morning stiffness of 1 h for at least 6 weeks
• Arthritis and soft tissue swelling of 3 joints, present for at least 6 weeks
• Arthritis of hand joints, present for at least 6 weeks
• Symmetric arthritis, present for at least 6 weeks
• Subcutaneous nodules in specific places
• Rheumatoid factor above the 95th percentile
• Radiological changes suggestive of joint erosion

Q. Enlist the salient clinicopathological features of juvenile
rheumatoid arthritis (JRA).

Ans. Salient features of JRA:
• It is a chronic inflammatory condition that begins in patients under 16 years of age.
• Manifests with abrupt onset of spiking fever, transient skin rash, hepatosplenomegaly
and serositis and affects knees, wrists, elbows and ankles (large joints affected more than
small joints).
• It is typically RA-negative, rheumatoid nodule-negative and ANA-positive.

Q. What is infectious arthritis? Enlist its important clinicopathological
features.
Ans. Salient features of infectious arthritis:
• Infectious arthritis is defined as arthritis caused by infection with a microbial pathogen.
• May occur secondary to haematogenous spread, osteomyelitis and as a complication of
intra-articular infection or surgery.
• Common causative organisms are gonococci, meningococci, pneumococci, staphylococci,
streptococci, H. influenza, Gram-negative bacilli and M. tuberculosis.
• Patient presents with sudden onset of pain, swollen joints, restricted mobility, fever,
leucocytosis and increased ESR. Commonly involved joints include knees, hips, shoul-
ders, elbows and wrists.
• Predisposing conditions include immune deficiency, debilitating illness, joint trauma
and intravenous drug abuse.
• Tuberculous arthritis is a chronic progressive monoarticular arthritis, which mainly affects
the weight-bearing joints, eg, hips, knees and ankles. Systemic symptoms may or may
not be present.

Q. Enumerate the various crystallopathies.
Ans. Articular crystal deposits include
• Endogenous crystals: Monosodium urate (MSU), calcium pyrophosphate dihydrate
and calcium phosphate
• Exogenous crystals: Corticosteroids, talc, polyethylene and silicone

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