Joints Pathology

OSTEOARTHRITIS

Osteoarthritis Arthritis is joint inflammation, usually accompanied by pain, swelling and changes in the structure. Arthritis can generally be divided into two major forms: Inflammatory arthritis, usually involving the synovium and mediated by inflammatory cells (e.g. rheumatoid arthritis) Non-inflammatory arthritis (e.g. primary osteoarthritis.

Primary osteoarthritis Primary osteoarthritis is: “slow progressive destruction of articular cartilage that affects weight-bearing joints and fingers of older persons or the joints of younger individuals subjected to trauma.” Before the age of 45: the disease mainly affects men. After age 55: osteoarthritis is more common in women.

Pathology: Joints commonly affected by osteoarthritis are the proximal and distal inter-phalangeal joints of the hands, knees and hips as well as the cervical and lumbar segments of the spine.

Osteoarthritis is characterized by: Radiologically: Osteoarthritis is characterized by: Narrowing of the joint space Increased thickness of the subchondral bone Subchondral bone cysts Large peripheral growths of bone and cartilage, called osteophytes.

A: Cartilage erosion; B: Cartilage ulceration C: Cartilage repair D: Marginal osteophytes (arrows)

Osteoarthritis

Pathogenesis: Biomechanical: aging or wear and tear of articular cartilages Predisposing factors includes obesity, previous joint injury, diabetes, trauma and haemarthrosis

Clinical Features: The involved joints may be enlarged, tender and may give crepitus sensation. There is deep achy joint pain that follows activity and is relieved by rest.  

Discomfort is also caused by short periods of stiffness which is frequently experienced in the morning or after periods of minimal activity.   Restricted joint motion indicates severe disease. Therapy includes exercise, weight loss and other supportive measures. Joint replacement may be necessary in disabling osteoarthritis.

Osteoarthritis

Pathology: Weight bearing joints → knees, hips and spines Asymmetrical involvement Degeneration and loss of articular cartilage Eburnation ( exposed bone becomes polished) Sub-chondral bone sclerosis Subchondral bone cyst Loose bodies (joint mice) : free floating fragments of cartilages and bone Osteophytes (bone spurs): reactive boney outgrowths

RHEUMATOID ARTHRITIS Definition: A symmetric chronic inflammatory disease characterized by: 1-Progressive arthritis 2-Production of rheumatoid factors 3-Extra-articular manifestations

Incidence: Etiology: Females>males Age: 20-40 years An autoimmune reaction in genetically susceptible individuals

Clinical features: Hand, wrist and ankle joints are the most involved Tends to have symmetrical involvement Morning stiffness that improves with activity Fusiform swelling, redness and warmth of proximal inter-phalngeal joints

RHEUMATOID ARTHRITIS EARLY LATE

X-ray: Juxta-articular osteoporosis and bone erosions Joint effusion

RHEUMATOID ARTHRITIS

Pathology: Diffuse proliferative synovitis 2.Pannus formation: proliferation of the synovium and granulation tissue over the articular cartilage of the joint 3.Fibrous and boney ankylosis (joint fusion) 4.Joint deformities: Radial deviation of the wrist and ulnar deviation of fingers

Pannus formation

Extra Articular Manifestations of RhA 1- Systemic symptoms: includes low grade fever, malaise, fatigue and weakness 2- Rheumatoid nodules (25%) Subcutaneous skin nodules Usually on extensor surfaces of the forearms or elbow Composed of central fibrinoid necrosis surrounded by epithelioid macrophages, lymphocytes and granulation tissue May also be found in the heart valves, lungs, pleura, pericardium and spleen 3-Generalized amyloidosis

Rheumatoid nodules

Diagnosis of Rheumatoid Arthritis The clinical diagnosis of Rheumatoid Arthritis is based on a number of criteria such as the: Number and types of joints involved in the presence of Rheumatoid Arthritis nodules Positivity for RF (Rheumatoid Factor) Radiographic features characteristic of the disease

Sero-Negative Arthritis Rheumatoid factor negative arthritis includes: Ankylosing Spondylitis, Reiter Syndrome, Psoriatic Arthritis, and Arthritis Associated with Inflammatory Bowel Disease.

Shared features include: Seronegativity for RF Sacroiliac and vertebral involvement Asymmetric involvement of only few peripheral joints Systemic involvement of other organs, especially the eye, heart and aorta Occur in young men

Ankylosing Spondylitis Ankylosing spondylitis is an inflammatory arthropathy of the vertebral column and sacroiliac joints. It may be accompanied by asymmetric, peripheral arthritis (30% of patients) and systemic manifestations. It is most common in young men, with a peak incidence at about age 20.

Pathology: Ankylosing spondylitis begins at the sacroiliac joints bilaterally then ascends the spinal column by involving the joints of the spine.   The result is ultimate destruction of these joints after which the spine becomes fused.

Lateral lumbar spine X-ray demonstrating in ankylosing spondylitis The ankylosis process

Reactive Arthritis (Reiter Syndrome) Reactive arthritis is a triad that includes: Polyarthritis, Conjunctivitis Non-specific Urethritis It occurs almost exclusively in men and usually follows venereal infection or an episode of bacillary dysentery. More than half of the patients develop mucocutaneous lesions. In most patients, the disease remits within a year but progressive arthritis develops in 20% of cases.

Reactive Arthritis (Reiter Syndrome) Mucocutaneous Lesions

The Eye

Arthritis Associated with Inflammatory Bowel Disease (Enteropathic Arthritis) Ulcerative colitis and Crohn’s disease are accompanied by seronegative peripheral arthritis in 20% of cases and spondylitis in 10%.

GOUT DISEASE

Definition: Increase of serum uric acid and the deposition of sodium ureate crystals on the articular cartilage of joints, tendons and surrounding tissues This provokes an inflammatory reaction of these tissues

Types and causes of gout disease: Primary gout: a heterogeneous group with known and unknown enzymes defects Some cases have a hereditary predisposition Secondary gout: due to excess nucleoprotein destruction as in cases of chronic myeloid leukemia

Pathogenesis: -Increased serum uric acid (hyperuricemia) above normal ( normal is 3-6 %) -Monosodium urate (MSU) crystals deposition leads to: a) Acute arthritis: in joints particularly the big toe b) Chronic tophaceous arthritis: i.e. repeated attacks of arthritis → excessive deposition of mono-sodium urate crystals → chronic inflammation → fibrosis → joint ankylosis

Tophus Definition: The tophus is the principle lesion in gout disease A tophus is small nodular lesion formed due to the deposit of crystallized monosodium ureate in people with longstanding hyperuricemia and usually associated with symptoms of gout.

Tophi appear in the following organs: Joint structures: synovium, tendons, ligaments and cartilages Cartilage of ear and nose: causing ulceration over it Subcutaneous; particularly the eye lids also with ulceration Cardiac valves Kidney forming uric acid kidney stones and leading to renal failure.

Signs and symptoms: Gout is a form of arthritis that affects mostly men between the ages of 40 and 50 Gout is characterized by sudden unexpected burning pain as well as swelling, redness, warmth and stiffness in the affected joint

Tumors and Tumor-Like Lesions of Joints

Tumors and Tumor-Like Lesions of Joints True neoplasms of the joints are rare. Pigmented villonodular synovitis (PVS): Benign but often locally aggressive neoplasm, Characterized by exuberant proliferation of synovial lining cells with extension into the subsynovial tissue. The most common site (80%) is the knee

Pigmented Villonodular Synovitis

Malignant lesions of the synovium are most commonly metastatic carcinomas particularly adenocarcinoma of the colon, breast and lung. Primary malignant bone tumors may invade the joint capsule

Bursitis Inflammation of the Bursa (fluid filled sac surrounding the joint). A bursa can become inflamed from injury, infection or due to an underlying rheumatic condition. Bursitis is typically identified by localized pain or swelling, tenderness and pain with movement of the tissues in the affected area.

Tendonitis Inflammation of the tendon Leads to irritation and pain when pulling the muscle. The most common cause of tendonitis is overuse.

Carpal Tunnel Syndrome Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index and the middle fingers, a condition known as "carpal tunnel syndrome."

Scoliosis Scoliosis is an abnormal curvature of the spine. Scoliosis runs in families, but doctors often don't know the cause. Adult scoliosis may be a worsening of a condition that began in childhood, but wasn't diagnosed or treated. Also scoliosis may result from a degenerative joint condition in the spine.

Kyphosis It can affect children, adolescents and adults. With increased kyphosis the spine develops a hump. Kyphosis can occur as a result of: -developmental problems -degenerative diseases, such as arthritis of the spine -osteoporosis with compression fractures of the vertebrae -trauma to the spine.

Lordosis A spine affected by lordosis shows evidence of a curvature of the back bones (vertebrae) in the lower back area.

Talipes Equinovarus- “Clubfoot” Clubfoot is a deformity of the whole foot that is present at birth. There are several types of clubfoot that are known as 'talipes' as the deformity is mostly in the talus (a bone in the ankle). The most common of the talipes is what is known as "talipes equino varus“ and is referred to as clubfoot. In talipes equino varus, the child is born with the foot pointing down and twisted inwards at the ankle.