Bone Pathology

Normal anatomy of bones Parts of a long bones: Parts of a long bones: 1. diaphysis (shaft), 2. physis (growth plate), 3. epiphysis (ends of bone, partially covered by articular cartilage), 4. metaphysis (junction of diaphysis and epiphysis, most common site of primary bone tumors) Cross section: Cross section: 1. periosteum, 2. cortex (composed of cortical bone or compact bone), 3. medullary space (composed of cancellous or spongy bone)

OSTEOMYELITIS: OSTEOMYELITIS: Denotes inflammation of bones and marrow. Denotes inflammation of bones and marrow. May be a complication of any systemic infection but frequently manifests as a primary solitary focus of disease. May be a complication of any systemic infection but frequently manifests as a primary solitary focus of disease.

PYOGENIC OSTEOMYELITIS: PYOGENIC OSTEOMYELITIS: is almost always caused by bacteria. is almost always caused by bacteria. 1. Hematogenous spread. 2. Extension from a contiguous site. 3. Direct implantation. 4. E.coli and Pseudomonas. 5. Mixed bacterial infections. 6. Salmonella infections.

Clinical Course: Clinical Course: Fever,chills, malaise, marked to intense throbbing pain over the affected region. Fever,chills, malaise, marked to intense throbbing pain over the affected region. Diagnosis; Diagnosis; Sign/symptoms. Sign/symptoms. X-ray X-ray Blood cultures Blood cultures biopsy biopsy

Complications: Complications: Pathologic fracture. Pathologic fracture. Secondary amyloidosis Secondary amyloidosis Endocarditis Endocarditis Sepsis Sepsis Squamous cell carcinoma. Squamous cell carcinoma.

Tuberculous osteomyelitis: Tuberculous osteomyelitis: Routes of entry; Routes of entry; Usually blood borne and originate from a focus of active visceral disease. Usually blood borne and originate from a focus of active visceral disease. Direct extension (e.g. from a pulmonary focus into a rib or from tracheobronchial nodes into adjacent vertebrae) or spread via draining lymphatics. Direct extension (e.g. from a pulmonary focus into a rib or from tracheobronchial nodes into adjacent vertebrae) or spread via draining lymphatics.

Bone tumors Classification of primary tumors involving bones: Classification of primary tumors involving bones: Bone Forming tumors. Bone Forming tumors. Cartilage forming tumors. Cartilage forming tumors. Fibrous and fibro-osseous tumors. Fibrous and fibro-osseous tumors. Miscellaneous tumors. Miscellaneous tumors.

Arthritis Suppurative Arthritis Suppurative Arthritis Tuberculous Arthritis Tuberculous Arthritis Osteoarthritis Osteoarthritis Gout Arthritis Gout Arthritis Rheumatoid Arthritis Rheumatoid Arthritis

ARTHRITIS Suppurative arthritis: Suppurative arthritis: Due to seeding of joint during bacteremia, most commonly due to Staphylococcus, Streptococcus, gram negative rods; rarely syphilis Due to seeding of joint during bacteremia, most commonly due to Staphylococcus, Streptococcus, gram negative rods; rarely syphilis Also due to postsurgical infection Also due to postsurgical infection Neonates: often due to osteomyelitis Neonates: often due to osteomyelitis Young women: most commonly due to gonorrhea (gram negative intracellular diplococci, which is associated with multiple joint involvement, including the knee) Young women: most commonly due to gonorrhea (gram negative intracellular diplococci, which is associated with multiple joint involvement, including the knee) Sickle cell disease: Salmonella Sickle cell disease: Salmonella

ARTHRITIS Tuberculous arthritis: Tuberculous arthritis: Insidious onset of chronic progressive arthritis, usually monoarticular in knee and hip; usually after osteomyelitis Insidious onset of chronic progressive arthritis, usually monoarticular in knee and hip; usually after osteomyelitis Leads to fibrous ankylosis of joint with obliteration of joint space Leads to fibrous ankylosis of joint with obliteration of joint space Can detect from culture and examination of synovial fluid. Can detect from culture and examination of synovial fluid. PCR is sensitive; apparent false positives in clinically negative patients may represent early disease. PCR is sensitive; apparent false positives in clinically negative patients may represent early disease.

ARTHRITIS Degenerative joint disease: Degenerative joint disease: Also called osteoarthritis. Also called osteoarthritis. Nonneoplastic disorder of progressive erosion of articular cartilage associated with aging, trauma, occupational injury. Nonneoplastic disorder of progressive erosion of articular cartilage associated with aging, trauma, occupational injury. Usually age 50+ years (present in 80% at age 65 years) Usually age 50+ years (present in 80% at age 65 years) Cartilage degradation may be mediated by IL-1. Cartilage degradation may be mediated by IL-1. Sites: men-hips, women-knees and hands; also first metatarsophalangeal joint, lumbar spine; usually one joint or same joint bilaterally, at least initially Sites: men-hips, women-knees and hands; also first metatarsophalangeal joint, lumbar spine; usually one joint or same joint bilaterally, at least initially

Osteoarthritis Symptoms: pain worse with use of joint, crepitus, limited range of motion, nerve root compression; Heberden nodes in fingers of women only (osteophytes at DIP joints) Symptoms: pain worse with use of joint, crepitus, limited range of motion, nerve root compression; Heberden nodes in fingers of women only (osteophytes at DIP joints) Secondary degenerative joint disease: younger patients with predisposing condition (trauma, congenital, diabetes, obesity, ochronosis, hemochromatosis), such as knees of basketball players Secondary degenerative joint disease: younger patients with predisposing condition (trauma, congenital, diabetes, obesity, ochronosis, hemochromatosis), such as knees of basketball players

Osteoarthritis Gross: early changes are even degeneration of hyaline cartilage of articular surface, with fragmentation Gross: early changes are even degeneration of hyaline cartilage of articular surface, with fragmentation later thinning of cartilage and articular surface is often soft and granular with altered shape, sloughing of cartilage. later thinning of cartilage and articular surface is often soft and granular with altered shape, sloughing of cartilage. cysts: (synovial fluid forced into fractures via ball valve- like mechanism), cysts: (synovial fluid forced into fractures via ball valve- like mechanism), osteophytes: (bony outgrowths at margins of articular surface) osteophytes: (bony outgrowths at margins of articular surface)

Osteoarthritis Loose bodies: may form if portion of articular cartilage breaks off; normally loose body is nourished by synovium and continues to grow. Loose bodies: may form if portion of articular cartilage breaks off; normally loose body is nourished by synovium and continues to grow.

GOUT Gout and gouty arthritis Gout and gouty arthritis Transient attacks of acute arthritis initiated by crystallization of urates and neutrophils, followed by chronic gouty arthritis with tophi in joints and urate nephropathy Transient attacks of acute arthritis initiated by crystallization of urates and neutrophils, followed by chronic gouty arthritis with tophi in joints and urate nephropathy Causes 2-5% of chronic joint disease Causes 2-5% of chronic joint disease Sites: 50% have initial attack in first metatarsophalangeal joint; also ankles, heels, knees, wrists, fingers, elbows Sites: 50% have initial attack in first metatarsophalangeal joint; also ankles, heels, knees, wrists, fingers, elbows

GOUT Primary gout (90%): idiopathic (85%) with overproduction of uric acid or known enzyme defects. Primary gout (90%): idiopathic (85%) with overproduction of uric acid or known enzyme defects. Secondary gout (10%): increased nucleic acid turnover due to leukemia/lymphoma, chronic renal disease. Secondary gout (10%): increased nucleic acid turnover due to leukemia/lymphoma, chronic renal disease.

GOUT Gout is due to hyperuricemia and deposition of monosodium urate crystals in joints and viscera and uric acid kidney stone formation. Gout is due to hyperuricemia and deposition of monosodium urate crystals in joints and viscera and uric acid kidney stone formation. Need serum urate > 7 mg/dl for deposition (saturation threshold for urate at 98.6 F) Need serum urate > 7 mg/dl for deposition (saturation threshold for urate at 98.6 F) Risk factors for gout with hyperuricemia are age > 30 years, familial history of gout, alcohol use, obesity, thiazide administration, lead etc. Risk factors for gout with hyperuricemia are age > 30 years, familial history of gout, alcohol use, obesity, thiazide administration, lead etc.

Rheumatoid arthritis Chronic systemic inflammatory disorder affecting synovial lining of joints, bursae and tendon sheaths; also skin, blood vessels, heart, lungs, muscles Chronic systemic inflammatory disorder affecting synovial lining of joints, bursae and tendon sheaths; also skin, blood vessels, heart, lungs, muscles Produces nonsuppurative proliferative synovitis, may progress to destruction of articular cartilage and joint ankylosis Produces nonsuppurative proliferative synovitis, may progress to destruction of articular cartilage and joint ankylosis 75% are women, peaks at ages years; also menopausal women 75% are women, peaks at ages years; also menopausal women Sites: small bones of hand affected first (MCP, PIP joints of hands and feet), then wrist, elbow, knee Sites: small bones of hand affected first (MCP, PIP joints of hands and feet), then wrist, elbow, knee

Rheumatoid arthritis X-ray: joint effusions, erosions X-ray: joint effusions, erosions narrowing of joint space; destruction of tendons, ligaments and joint capsules produce radial deviation of wrist, ulnar deviation of digits, swan neck finger abnormalities narrowing of joint space; destruction of tendons, ligaments and joint capsules produce radial deviation of wrist, ulnar deviation of digits, swan neck finger abnormalities

Rheumatoid arthritis Diagnosis: morning stiffness, arthritis in 3+ joint areas morning stiffness, arthritis in 3+ joint areas arthritis in hand joints, arthritis in hand joints, symmetric arthritis, symmetric arthritis, rheumatoid nodules, rheumatoid factor, typical radiographic changes rheumatoid nodules, rheumatoid factor, typical radiographic changes

OSTEOPOROSIS Is a term that denotes increased porosity of the skeleton resulting from reduction in the bone mass. Primary: 1- post menopausal 2- Senile Secondary: 1- Endocrine Disorders

Pathophysiology Of Osteoporosis  AGING 1- ↓ replicative activity of the osteoprogenitorcells 2- ↓ synthetic activity of the osteoblasts. 3- ↓ activity of the matrix bound growth factors.  Menopause: 1- ↓ serum estrogen 2- ↑ IL-1,IL-6 levels 3- ↑ osteoclast activity  Genetic factors  Nutritional effects

OSTEOPOROSIS Prevention Strategies Prevention Strategies The best long-term approach to osteoporosis is prevention. The best long-term approach to osteoporosis is prevention. children and young adults, particularly women, with a good diet (with enough calcium and vitamin D) and get plenty of exercise, will build up and maintain bone mass. children and young adults, particularly women, with a good diet (with enough calcium and vitamin D) and get plenty of exercise, will build up and maintain bone mass. This will provide a good reserve against bone loss later in life. This will provide a good reserve against bone loss later in life. Exercise places stress on bones that builds up bone mass Exercise places stress on bones that builds up bone mass