10.1 Bones Highlights Flashcards
* = also MJ slide
What makes up the 2 components of bones?
1) Osteoid (35%): collagen
2) Minerals (65%): phosphate + calcium (mostly)
Define:
1) Osteoblasts
2) Osteoclasts
1) Synthesize bone matrix and regulate its mineralization
2) Specialized macrophages responsible for resorption
Congenital Bone Disease: List the 3 ways Dysostoses can manifest
1) Aplasia (absent)
2) Supernumerary (extra bones or digits)
3) Syndactyly/ craniosynostosis (abnormal fusion)
Congenital Bone Disease: What are 2 groups?
1) Dystoses
2) Dysplasias
Dysplasias:
1) What do they arise from?
2) In this context, refers to abnormal growth, NOT a _______________ lesion
1) Mutations in genes that control the development of the entire skeleton
2) pre-malignant
*List the 4 predominant features of osteogenesis imperfecta
1) Skeletal fragility
2) Blue sclera
3) Sensori-neural hearing loss and or conductive hearing loss
4) Dental imperfections (small misshapen bluish-yellow teeth)
*What is THE most important Sx of Osteogenesis Imperfecta?
Skeletal fragility (fragile bones!)
1) Osteogenesis Imperfecta is diverse in what way?
2) What is it the most common of?
1) Phenotypically diverse
2) Most common inherited disorder of connective tissue (1/20,000)
Osteopetrosis “marble bone disease”:
1) Reduced formation or function of osteoclasts leads to what?
2) What form is severe? What can it cause and what can it lead to?
3) What can make it fatal?
4) Give 2 facts abt the adult form
1) Diffuse skeletal sclerosis.
2) Infantile form; Extramedullary hematopoiesis can lead to hepatosplenomegaly
3) Leukopenia
4) Autosomal dominant + Incidentally detected on radiographs
*Osteoporisis
1) What is the physiologic average bone loss of bone mass per year with osteopenia?
2) Osteoporosis → Osteopenia severe enough to risk fracture most likely in what 2 groups?
3) List 1 of the many aspects of pathogenesis
1) Physiologic average bone loss 0.7% of bone mass per year
2) Geriatric + Post-menopausal
3) Hormonal influences (estrogen in particular)
1) What 2 things can menopause lead to to cause osteoporosis?
2) What abt aging?
1) Decrease serum estrogen; increased osteoclast activity.
2) Reduced physical activity
Rickets and Osteomalacia:
1) Who is rickets found in? Why?
2) Who is osteomalacia found in?
3) What is a common cause?
1) Children; interferes with deposition of bone in the growth plates
2) Adults; bone formed during remodeling is undermineralized
3) Vitamin D deficiency → impairment of mineralization and deposition of unmineralized matrix
Paget disease of the bone is characterized by what kind of bone?
Increased, but disordered and structurally unsound bone
Pagent disease of the Bone
1) What are 2 primary causes?
2) List 2 other manifestations and define each
3) What can develop with this condition?
1) a) Genetic
b) Environmental: [possibly relating to viral infection (measles) of osteoclast precursors alters vit D sensitivity or IL-6 production]
2) Leontiasis ossia “lion face”: enlargement of craniofacial skeleton
Platybasia: flattening of skull base due to weakening and ↑ weight
3) Tumor-like conditions; <1% develop into osteosarcoma
-Unless malignant transformation happens, Paget’s is usually not fatal.
List the 4 steps of Fx healing
1) Hematoma (0-1 day)
2) Soft callus
3) Bony callus formation
4) Bony callus (3 weeks-months)
*List 4 predisposing factors for AVN (osteonecrosis)
1) Vascular injury (trauma or vasculitis)
2) Drugs (corticosteroids
3) Systemic disease (sickle cell)
4) Radiation
*What is the most important cause of AVN?
Trauma
What are 3 mechanisms of AVN?
1) Mechanical disruption of vessels
2) Thrombotic occlusion
3) Extravascular compression
*What are the 3 Sx of AVN?
1) Subchondral infarct-activity related pain → constant pain
2) Collapse: worse pain
3) Secondary arthritis
*What are 2 types of osteomyelistis?
Pyogenic and mycobacterial (TB)
*Pyogenic osteomyelitis: What causes it?
Almost always bacterial, rarely fungal
-Staph aureus (80-90%)
*2 major types of benign bone forming tumor are?
Osteoid Osteoma + osteoblastoma
*Define Osteosarcoma (malignant)
Aggressive tumor of malignant osteoblasts
List 3 cartilage-forming tumors and specify which is malignant
1) Osteochondroma
2) Chondroma
3) Chondrosarcoma (malignant)
Give an example of a tumor of unknown origin. What is unique about this one?
Ewing Sarcoma; have the youngest average age presentation
True or false: Metastatic tumors greatly outnumber primary tumors of the bone
True
1) Rheumatoid Arthritis is a chronic ______________ inflammatory disease
2) Caused by cell mediated and humoral immunity response against ______________.
3) List 2 characteristics.
4) TNF and IL1 from macrophages stimulate what?
1) Chronic autoimmune inflammatory disease
2) self-antigens
3) Synovial hyperplasia + pannus formation
4) Synovial cells to secrete proteases and destroy hyaline cartilage.
*Crystal-Induced Arthritis: List 2 kinds and what the crystals are made of
1) Gout: urate
2) Pseudogout: calcium pyrophosphate
(mnemonic: pseudo starts with p, pyro starts w p; gout likes great toe)
Infectious Arthritis:
1) List 3 mechanisms of infectious arthritis spread
2) Suppurative infectious arthritis usually has what kind of spread?
1) a. Hematogenous dissemination
b. Direct inoculation through skin
c. Contiguous spread from soft tissue abscess of osteomyelitis
2) Usually, hematogenous spread
Infectious Arthritis:
1) What are the suppurative pathogens [by age] of infectious arthritis in general?
2) What causes Lyme arthritis?
3) What are the stages of Lyme arthritis?
1) Children <2: H. influenza
Children & older adults: Staph aureus
Gonococcal: late adolescent through early adulthood.
2) Spirochete : Borrelia burgdorferi
3) Early = skin
-Early disseminated = skin, cranial nerves, heart, and meninges
-Arthritis occurs weeks or months after inoculation (usually knee; migratory arthritis is aka Lyme arthritis)
Peripheral Nerve Disorders: What are the 2 types of injury?
1) Axonal- (Wallerian degeneration=secondary loss of myelin sheath)
2) Demyelinating
*1) Guillain-Barre’ Syndrome is Rapidly progressive affecting the ________ of the motor axons
2) When is it triggered medically?
3) What else can it follow? Give an example
1) myelin
2) when injection of vaccine breaks down self-tolerance → autoimmune response
3) Campylobacter jejuni
*What is the most common cause of peripheral neuropathy?
Diabetic Peripheral Neuropathy
*Diabetic Peripheral Neuropathy: List at least 3 forms
1) Autonomic neuropathy: Characterized by changes in bowel, bladder, cardiac, or sexual function
2) Lumbosacral radiculopathy: Asymmetric pain with muscular weakness +/- atrophy
3) Distal symmetric sensorimotor polyneuropathy: Sensory affected > Motor
*Diabetic Peripheral Neuropathy
1) What is the kind we’ve heard about before?
2) What is most affected?
1) Distal symmetric sensorimotor polyneuropathy
2) Sensory > Motor
- Myasthenia Gravis
1) Autoantibodies that target what?
2) List 3 clinical manifestations
1) Post-synaptic acetylcholine receptor
2) Ptosis (drooping eyelid)
Diplopia (double vision)
EOM weakness
List 3 Inherited disorders of skeletal muscle
1) Muscular dystrophies (dystrophinopathies)
2) Congenital muscular dystrophies
3) Congenital myopathies
*Dysytrophinopathies
1) Most common dystrophies are _______-linked.
2) What causes it? (pathophys/ chain of events)
1) X-linked
2) Mutations that disrupt dystrophin ( a large structural protein) → which disrupts the dystrophin-glycoprotein complex →transient membrane tears during contraction
*What are the 2 principle dystrophy diseases?
1) Duchenne muscular dystrophy: usually diagnosed in childhood → wheelchair bound by teens → dead by early adulthood
2) Becker muscular dystrophy: less common and less severe
Define myotonia
Sustained involuntary contraction of a group of muscles
