Joint diseases Group I: Non-inflammatory osteoarthritis neuropathic (Charcot’s joint) Group II: Inflammatory rheumatoid arthritis gout pseudogout ankylosing spondylitis Reiter’s disease psoriatic arthritis Group III: Septic infectious arthritis due to bacteria, fungi, and viruses Group IV: Hemorrhagic hemophilia trauma scurvy

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Joint diseases
Part -1
Med_students0

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Basics
• Joints provide movement and support.
• Classification:
– Solid (nonsynovial)
• also known as synarthroses ; lack a joint
space
• allow minimal movement
– Cavitated (synovial):
• have a joint space
• allow for a wide range of motion.

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Synovial joint

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Joint space
• Boundary formed by synovial membrane.
• Lined by synoviocytes.
• Synovial fluid (SF):
– Is secreted by synoviocytes.
– Pale yellow to clear, viscous
– Rich in hyaluronic acid: acts as lubricant
– provides nutrition for articular cartilage.
• Arthrocentesis: needle aspiration of SF

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Synovial fluid analysis
• Routine studies of SF:
– Gross appearance: normally pale yellow
– WBC count and differential count :
• normally <200 cells mm3,
• neutrophils <25% of total count.
– Culture & Gram stain :if infection is
suspected
– Crystal analysis

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Synovial fluid analysis
SF in infectious arthritis
Normal SF

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Crystal identification
• Monosodium urate (MSU) : found in gout
– needle shaped (monoclinic)
– Special polarization shows negative
birefringence
• Crystal is yellow when parallel to slow ray
• Calcium pyrophosphate dehydrate (CPPD)
crystals: found in pseudogout.
– Monoclinic or triclinic (rhomboid)
– Special polarization shows positive
birefringence
• Crystal is blue when parallel to slow ray

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Monosodium urate crystal
Monoclinic crystal
Negative birefringent
Calcium Pyrophosphate
Triclinic crystal
+ve birefringent crystal

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Clinical manifestations of joint diseases
• Pain,
• Arthralgia: refers to pain in a joint without
inflammation
• Arthritis: pain in the joint with
inflammation.
• Abnormal mobility: due to damage to
ligament or joint capsule
• Morning stiffness, swelling.
• Crepitus: crackling sensation on moving the
joint.

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Classification of joint diseases
Subdivided into four major categories
• Group I: Non-
inflammatory
– osteoarthritis
– neuropathic (Charcot’s
joint)
• Group II: Inflammatory
– rheumatoid arthritis
– gout
– pseudogout
– ankylosing spondylitis
– Reiter’s disease
– psoriatic arthritis
• Group III: Septic
– infectious arthritis due
to bacteria, fungi, and
viruses
• Group IV: Hemorrhagic
– hemophilia
– trauma
– scurvy

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Group I: Non-inflammatory joint disorders
Osteoarthritis

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In a normal joint
Cartilage lubricated by
synovial fluid,
cushions the bones
and
allows friction less motion

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Osteoarthritis (OA)
• Most common type of joint disease and joint
disability in the US.
• Non-inflammatory joint disease (unlike its
name).
• Is a degenerative joint disease and is
characterized by:
– Progressive erosion (degeneration, loss) of
articular cartilage and
– Associated reactive changes at the margin
of the joints and in the subchondral bone.

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• Epidemiology:
– OA is age dependent process
– Universal after 65 years of age
– More common in women.
• Joints involved: Primarily targets
weight bearing joints
– Hips, knees
– cervical and lumbosacral spine &
– Other joints:
• Distal interphalangeal joint (DIP)
and proximal interphalangeal joint
(PIP) of the hands
Osteoarthritis (OA)

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OA types
• Primary: as a result of aging phenomenon;
– seen in older individuals
• Secondary: develops as a result of a
predisposing condition
– seen in younger individuals
• Trauma to joint (players)
• Obesity (knees, particularly in women)
• Ochronosis* : (Alkaptonuria: accumulation
of homogentisic acid)
• Hemochromatosis*.

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Pathogenesis
• Exact etiology of OA osteoarthritis is
unknown.
• Most important factor that predisposes
to development of OA is
– effect of abnormal load (mechanical
trauma) on a weight bearing joint.

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In a normal joint
Cartilage lubricated by
synovial fluid,
cushions the bones
and
allows friction less motion

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1. Thinning of articular cartilage
2. Development of cracks
• (= fibrillation)

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•Erosion and loss of cartilage

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• Formation of :
1.Loose body (Joint mice)
2.Subchondral cyst

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1.Eburnation
2.Sclerosis
3.Narrowing of joint space
4.Osteophyte

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Eroded Cartilage
Articular surface of femur

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Articular cartilage

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Osteophyte

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Eburnated articular surface
Subchondral cyst.
Residual articular cartilage

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Pathology
• Joint findings:
– Erosions and clefts in articular cartilage
• Clefts penetrate into underlying
subchondral bone, a process called
fibrillation.
– Fragmentation of cartilage and subchondral
bone result in formation of loose bodies
(joint mice).
– Bone rubs on bone  polished ivory like
appearance (called eburnation).
– Subchondral bone cysts (visible on X rays)
develop beneath the articular surface.

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Osteophytes

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Heberden’s nodes
(DIP)
Bouchard’s nodes
(PIP)

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• Reactive bone formation at the margins of
joints produce osteophytes (bony spurs).
• These are responsible for:
– Heberden’s nodes found at the base of the
distal interphalangeal joints (DIP) of the
hands.
– Bouchard’s nodes in the proximal
interphalangeal (PIP) joints of the hand
Pathology

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Clinical findings
• Non-inflammatory joint disease
• Pain with passive motion of joint:
– Due to secondary synovitis.
• Joint stiffness: with limitation of movement.
• Crepitus:
• Heberden’s nodes develop in the DIP joints and
• Bouchard’s nodes in the PIP joints of the hand

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Osteoarthritis
• Lab studies:
– No specific laboratory abnormality.
– Synovial fluid analysis : normal
• Imaging studies:
– Presence of osteophyte ( at joint
margins)
– Joint space narrowing
– Subchondral bone cysts
– No ankylosis* (fusion) of joint

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Axial CT scan obtained through the superior
aspect of the hip joint reveals osteoarthritis.
Subchondral cysts
Joint-space narrowing
Osteophyte
formation

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Neuropathic arthropathy (Charcot’s joint)
• Noninflammatory joint disease
• Secondary to a neurologic disease.
– Joint destruction is due to insensitivity to
pain
• Pathogenesis:
– loss of proprioception and deep sensation
leads to recurrent trauma 
– progressive destruction, and
disorganization of the joint

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Neuropathic arthropathy (Charcot’s joint)
• Causes:
– Diabetes mellitus (MC cause)
(tarsometatarsal joint)
– Syringomyelia (shoulder, elbow, wrist
joints)
– Tabes dorsalis (hip, knee and ankle
joint)

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Marked joint destruction is the
hallmark of a neuropathic joint
Charcot’s joint

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Additional Images
Self Study

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