Week 3 Non neoplastic diseases of bones, joints, and connective tissue Flashcards
Describe osteogenesis imperfecta.
- group of hereditary disorders with abnormal Type I collagen production
- most common is autosomal dominant
- bones are thin, ill formed, fractures early in life, heal improperly–>short stature
- other structures: blue sclerae, lax ligaments, weak teeth, deafness
Describe achondroplasia.
- mutation in fibroblast growth factor 3 FGFR3
- most common cause of dwarfism
- defect in cartilage synthesis, affects long bones
Describe osteopetrosis-Marble bone
- defect in osteoclastic reabsorption-leads to dense bone
- bones are brittle
- limited marrow space–> anemia, thrombocytopenia, infections, nerve compressions
Describe Marfan Syndrome.
- autosomal dominant, risk increases with paternal age
- mutation in fibrillin gene, FBNI
- tall stature, long fingers, lax ligaments, ocular changes,
- CV lesions: dilatation of aorta from cystic medial necrosis
Describe acute pyogenic osteomyelitis.
- most common in children, young adults, present as fever, pain
- etiology: usually Staph aureus, enter via blood stream
- sequestrum: bone necrosis caused by acute inflammation
- involucrum-reactive sleeve of new bone growth, may develop below periosteum
- radiograph: lytic and sclerotic features
What can happen if acute pyogenic osteomyelitis goes untreated?
- progress to chronic suppurative osteomyelitis
- draining sinuses often form between infected bone and skin
- can develop squamous cell carcinomas at site of draining sinuses
Describe tuberculosis of the bone.
- insidious with low grade fever and weight loss
- Pott disease-common affects spine
- chronic and acute inflammation, granulomas, necrosis on histology
- AFB stains often positive
Define osteoporosis.
- decrease in total mass of bone with micro-architectural deterioration
- bone loss that produces pain and or increased susceptibility to fracture
- very common,
What is the etiology/pathogenesis of osteoporosis?
- Primary: most common form, related to aging as resorption outpaces formation of bone, women mainly affected
- secondary: bone loss occurs from immobilization, endocrine disorders, drugs, malnutrition, malabsorption
What are the features of osteoporosis?
- fractures of weight bearing bones
- loss of height, spine deformity
- back pain
- radiograph: not detected until it exceeds 30% bone loss
- histology: thinned cortical and traecular bone
Describe osteomalacia/Rickets.
-structural abnormality of bone caused by defective mineralization of osteoid
-cause: lack of Vit D
Rickets-children
-results in lack of mineralization of osteoid and disruption of epiphyseal cartilage and growth
-see deformities
Osteomalacia-adults
-decreased mineralization of osteoid
-diffuse osteopenia
-LAB: increase in alkaline phosphatase, decrease in Ca and P
-Histology: trabeculae have peripheral seams of uncalcified osteoid
Describe Paget disease.
- mostly males >40, may involve one bone (monostotic) or many (polyostotic)
- bone thickening leads to deformities like increasing skull size, bowing of long bones in legs, fractures, esp. in spine
- radiograph: enlarged affected bones, lucency in early phase, irregular sclerosis in later phase
- histology: thickened irregular trabecular with cement lines
- lab: increase in alkaline phosphatase with no other changes
what are the complications that can occur with Paget disease?
- high output heart failure from AV shunts caused by hyper vascular bone
- secondary sarcoma in affected bone
Describe fibrous dysplasia.
- disorder of bone with progressive replacement of a localized area of bone by abnormal proliferation of benign fibrous tissue and bony trabecular composed of haphazardly arranged bone
- can be monostotic or polystotic
- radiograph: well demarcated, lucent, ground glass appearance of lesions
- expansion of medullary space, cortex intact
- histology: mature fibrous tissue with admixed, woven bone trabecular
