Bone and Joints pathology Flashcards
1
Q
Denervation atrophy
A
- Involved both type I (red) and type II (white) fibers
- Target fibers may also be seen
- After reinnervation - fiber-type grouping, clusters of type I and type II, may be seen
2
Q
Difuse atrophy
A
- Associated with prolonged immobilization
- Characterized by angular atrophy, primary of type II fibers
3
Q
Duchenne muscular dystrophy
A
- Most common and most severe of the muscular dystrophies
- Replacement of skeletal muscle by adipose tissue
- Begins with weakness in the proximal muscles of the extremities –> immobilization, wasting, muscle contracture, and death in early teens
- Caused by deficiency of dystrophin - X-linked inheritance
- Random variation in muscle fiber size, necrosis of individual muscle fibers, and replacement of necrotic fibers by fibrofatty tissue
- Characterized by calf pseudohypertrophy
- Serum creatine kinases is elevated
4
Q
Becker muscular dystrophy
A
- Clinical similar, but less severe than, Duchenne muscular dystrophy
- Caused by abnormality in dystrophin - molecule is truncated and presumably less functional
- Caused by segmental deletions within the gene that do not cause a coding frameshift
5
Q
Facioscapulohumeral muscular dystrophy
A
- Autosomal dominant inheritance
- Associated with slowly progressive, nondisabling course and an almost-normal life expectancy
- Involves muscles of face, scapular area, and humerus
6
Q
Limb-girdle dystrophy
A
- Autosomal recessive inheritance
- Involves proximal muscles of the shoulder, pelvic girdle, or both
7
Q
Myotonic dystrophy
A
- Autosomal dominant mode of inheritance
- Weakness associated with myotonia (inability to relax muscles once contracted)
- Associated features include cataracts, as well as testicular atrophy and baldness in men
- Caused by increased number of trinucleotide repeats - CTG repeats
8
Q
Central core disease
A
- Loss of mitochondria and other organelles in he central portion of type I muscle fibers
- Characterized by muscle weakness and hypotonia
- Affected infants eventually become ambulatory
9
Q
Nemaline myopathy
A
- Tangles of small rod-shaped granules, predominantly in type I fibers
- Varies clinically from a mild, nonprogressive disease to severe weakness ending in death from respiratory failure
10
Q
Mitochondrial myopathies
A
- Non-Mendelian inheritance
- Mediated by maternally transmitted mitochondrial DNA abnormalities
- May be characterized by ragged red appearance of muscle fibers and by various mitochondrial enzyme or coenzyme defects
11
Q
Myasthenia gravis
A
- Autoimmune disorder
- Caused by antoantibodies to postsynaptic acetylcholine receptors of the neuromuscular junction
- More common in women
- Characterized by muscle weakness intensified by muscle use, with recovery on rest
- Involves extraocular and facial muscles, muscles of the extremities, and other muscle groups
- Ptosis or diplopia, difficulty in chewing, speaking, or swallowing
- Symptoms improve with anticholinesterase agents
- Associated with tumors of the thymus or with thymic hyperplasia
12
Q
Lambert-Eaton syndrome
A
- Paraneoplastic disorder - most commonly associated with small cell carcinoma of the lung
- Caused by a defect in the release of acetylcholine by nerve cells
- May be due to acquired autoantibodies that react with presynaptic voltage-gated calcium channels
13
Q
Osteoporosis
A
- Characterized by a decrease in bone mass due to loss of bone matrix
- May be caused by impaired synthesis or increased resorption of bone matrix protein
- Most common bone disorder in older persons
- Results in bone structures inadequate for weight bearing - fractures commonly occur
- Assocaited with postmenopausal state and estrogen deficiency
- Present with fractures, kyphosis, and shortened stature
- Predisposed by: postmenopausal state, physical inactivity, hypercorticism, hyperthyroidism, calcium deficiency
14
Q
von Recklinghausen disease of bone (osteitis fibrosa cystic)
A
- Caused by primary or secondary hyperparathyroidism
- May manifest as “brown tumor” of bone
- Can be morphologically indistinguishable from giant cell tumor of bone
- Lab: hyperparathyroidism, high serum calcium, low serum phosphorus, and high serum alkaline phosphatase occur
15
Q
Osteomalacia
A
- Vitamin D deficiency in adults
- Characterized by defective calcification of osteoid matrix
- Result in weak bone with increased risk for fracture
- Lab: decreased serum calcium and serum phosphate, increased PTH and alkaline phosphatase
- When secondary to renal disease, osteomalacia is called renal osteodystrophy
16
Q
Rickets
A
- Vitamin D deficiency in children
- Increased thickness of the epiphyseal growth plates and other skeletal deformities
- Clinical: Craniotabes, late closing of fontanelles, rachitic rosary, harrison groove, pigeon breast, decreased hight
17
Q
Paget disease of bone
A
- Most common in the elderly
- Imbalance between osteoclast and osteoblast function
- Etiology is unknown; possibly viral
- Localized process involving one or more bones; does not involve entire skeleton
- Involves most commonly the spine, pelvis, calvarium of the skull, femur, and tibia
- Stages; (1) Osteoclastic, (2) Mixed osteoblastic - osteoclastic (3) Osteoblastic
- End result is thick sclerotic bone that fractures easily
- Complications: bone pain resulting from fractures, high-output cardiac failure, hearing loss, osteosarcoma
18
Q
Scurvy
A
- Caused by ascorbic acid (vitamin C) deficiency
- Characterized by bone lesions leading to impaired osteoid matrix formation - caused by failure of the proline and lysine hydroxylation required for collagen synthesis
- Bone changes: subperiosteal hemorrhage, osteoporosis, epiphyseal cartilage not replaced by osteoid
19
Q
Achondroplasia
A
- One of the most common cause of dwarfism
- Autosomal dominat disorder caused by mutation in the fibroblast growth factor receptor 3 gene
- Characterized by short limbs with a normal-sized head and trunk
20
Q
Fibrous dysplasia
A
- Characterized by replacement of portions of bone with fibrous tissue
- Unknown etiology
(1) Monostotic fibrous dysplasia - soliraty lesions that are often asymptomatic
(2) Polystotic fibrous dysplasia - multiple sites are involved
(3) McCune-Albright syndrome - polyostotic fobrous dysplasia, precocious puberty, cafe-au-lai spots on skin, and short stature
21
Q
Aseptic necrosis
A
- Most often of unknown etiology
- Most often results from infarction caused by interruption of arterial blood supply
- Can be secondary to trauma or to embolism of diverse types
- Clinical: femur (Legg-Calve-Perthes disease), tibial tubercle (Osgood-Schlatter disease), or the navicular bone (Kohler bone disease)
22
Q
Osteogenesis imperfecta
A
- Characterized by multiple fractures occurring with minimal trauma (brittle bone disease)
- Caused by a group of specific gene mutations, all resulting in defective collagen type I synthesis
- Blue sclerae
23
Q
Osteopetrosis
A
- Characterized by greatly increased density of the skeleton - abnormally thick, heavy bone that fractures easily
- Inherited defect of bone resorption
- Caused by failure of osteoclastic activity
- Multiple genetic variants
- Carbonic anhydrase II mutation results in lack of acidic environment required for resorption on bone
- Associated with anemia, blindness, deafness, and cranial nerve involvement
- Treatment: bone marrow transplant
24
Q
Osteomyelitis
A
- Infection of marrow space and bone; usually occurs in children
- Most often bacterial; arises due to hematogenous spread
- Seed metaphysis in kids, epiphysis in adults
- Causes: S. aureus, N gonorrhoeae, Salmonella, Pseudomonas, Pasteurella, TB
- Clinical: bone pain with fever and leukocytosis, lytic focus surrounded by sclerosis on x-ray
25
Q
Osteochondroma
A
- Most common benign tumor of bone
- Bone growth covered by a cap of cartilage projecting from the surface of a bone
- Most often originates from the metaphysis of long bones, with the lower end of the femur or the upper end of the tibia being favored locations
26
Q
Giant cell tumor
A
- Benign bone tumor
- Characterized by a monotonous oval- or spindle-shaped cells intermingled with numerous multinucleate giant cells
- Occurs most often in the epiphyseal end of long bones; more than 50% occur around the knee
- Locally aggressive tumor and often recurs after local curettage
- May be associated with secondary formation of an aneurysmal bone cyst (ABC) - “soap bubble” appearance on x-ray
27
Q
Osteosarcoma
A
- Second most common primary malignant tumor of bone (after plasma cell myeloma)
- Malignant proliferation of osteoblast
- Occurs most frequently in the metaphysis of long bones; around the knee
- Clinical: pain and swelling, increase in serum alkaline phosphatase, Codman triangle, “sunburst” pattern, early hematogenous spread to bones, lungs, liver, and brain
- Risk factors: familial RB, Paget disease of bone, fibrous dysplasia, chondroma, osteochondroma, ionizing radiation, bone infarctions
- High-grade central lesions (the most common)
28
Q
Chondrosarcome
A
- Malignant cartilaginous tumor
- Arises in medulla of pelvis of central skeleton
- May arise as a primary tumor or from transformation of preexisting cartilaginous tumors
29
Q
Ewing sarcoma
A
- “Small blue cell” malignant tumor
- Proliferatio of poorly-differentiated cells derived from neuroectoderm
- Arises in the diaphysis of long bones, usually in male children <15 yrs
- Occurs most often in long bones, ribs, pelvis, and scapula
- Follows and extremely malignant course with early metastases
- Present with: Painful, tender and swollen mass, fever, elevated sedimentation rate, anemia and leukocytosis, mimic infection
30
Q
Rhematoid arthritis
A
- Chronic, systemic autoimmune disease
- Associated with HLA-DR4-positive individuals
- Hallmark is synovitis leading to formation of pannus (inflamed granulation tissue)
- Serum rheumatoid factor, IgM autoantibody, against Fc portion of IgG. Neutrophils and high protein in synovial fluid
- Morning stiffness that improves with activity
- Symmetric involvement of PIP joints of the fingers, wrists, elbows, ankles, and knees
- Clinical: joint space narrowing, loss of cartilage, osteopenia, fever, malaise weight loss, myalgias, rheumatoid nodules, vasculitis, baker cyst, pleural effusion, LAD, and interstitial lung fibrosis
- Variants: Sjøgren syndrome, Felty syndrome, Still disease
31
Q
Seronegative spondyloarthropathies
A
- Lack of rheumatoid factor
- Axial skeleton invovlement
- High incidence in HLA-B27-positive individuals
- Peripheral arthritis
- Sacroiliitis
(1) Anykolsing spondylitis - HLA-B27 association, affects spine and sacroiliac joints
(2) Reiter syndrome - urethritis, conjunctivits, and arthritis; associated with general or intestinal infection
(3) Psoriatic arthrits
(4) Arthritis associated with inflammatory bowel disease
32
Q
Osteoarthritis (degenerative joint disease)
A
- Most common form of arthritis
- Progressive degeneration of articular cartilage
- Most often due to “wear and tear”
- Risk factors: age, obesity and trauma
- Involves hip, lower lumbar spine, knees, DIP and PIP of fingers
- Clinical: joint stiffness in the morning that worsens during the day
- Disruption of the cartilage that lines the auricular surface, Eburnation of the subchondral bone. Osteophyte formation
33
Q
Gout
A
- Deposition of MSU crystals in tissues, especially in the joints. Begins with opsonization of crystals by IgG
- Due to hyperuricemia
- Primary gout: Most common form, etiology of hyperuricemia is unknown
- Secondary gout: Hyperuricemia cause by Leukemia and MPDs, Lesch-Nyhan syndrome, Renal insufficiency
- Acute gout: Painful arthritis of the great toe (podagra), caused by alcohol and consumption of meat
- Chronic gout: Tophi - uric acid crystals in soft tissue or joints, renal failure - uric acid deposition in tubules
34
Q
Pseudogout (chondrocalcinosis)
A
- Caused by calcium pyrophosphate dehydrate crystal deposition
- Inflammatory raction in cartilage
- Rhomboid-shaped crystals with weak positive birefringence under polarized light
35
Q
Infectious arthritis
A
- Charcterized by purulent synovial fluid
- Due to infectious agnt, usually bacterial
- N. gonorrhoeae - young adults; most common overall cause
- S. aureus - older children and adults; 2nd most common cause
- Clinical: involves a single joint, usually the knee. Warm, erythematous joint with limited range of motion. Fever, increased WBC, and elevated ESR.
36
Q
Hypertrophic osteoarthropathy
A
- Associated with systemic disorders, such as chronic lung disease, congenital cyanotic heart disease, cirrhosis of the liver, and inflammatory bowel disease
- Clubbing of the fingers; periostitis at the distal end of the radius and ulna
- Clinical: painful swelling and tenderness od the peripheral joints
37
Q
Ganglion cyst
A
- Small cystic nodule arising in the tendon sheath or the joint capsule of the wrist
- Due to myxoid degeneration of connective tissue
38
Q
Rhabdomyosarcoma
A
- Malignant tumor of skeletal muscle
- Most common malignant soft tissue tumor in children
- Rhabdomyoblast is the characteristic cell; desmin positive
- Most common site is head and neck; vagina is a classic site in young girls
- Several variants: pleomorphic, emrbyonal, and alveolar
39
Q
Synovial sarcoma
A
- Highly malignant soft tissue tumor
- Most often originates in tissue adjacent to a joint, rather than in a join cavity
- No etiologic or direct anatomic relationship to the synovium
- Often occurs in he lower extremities
- X;18 translocation
- Commonly biphasic with both spindled and epithelial contributions
40
Q
Fibrous histocytoma
A
- Benign tumor
- Consisting of a mixture of fibroblasts and histiocytes
41
Q
Fibrosarcoma
A
- Malignant tumor of fibroblasts
- characterized by spindle-shaped cells demonstrating a herringbone pattern
42
Q
Lipoma
A
- Benign tumor of mature adipose tissue
- Most common benign soft tissue tumor in adults
43
Q
Liposarcoma
A
- Malignt tumor of adipose tissue
- Most common malignant soft tissue tumor in adults
