MSK Patho (Schoenwald) Flashcards
What are two types of metabolic bone disease?
Osteoporosis
Rickets
What is the cause of disease in osteoporosis?
Reduced mass of mineralized bone due to imbalance of bone metabolism resulting in Increased bone resorption
What is the cause of disease in Rickets?
Calcium metabolism (related to a vitamin D issue)
Is osteomyelitis infectious?
Yes
Is osteoarthritis infectious?
No
What is Paget disease?
Excessive osteoblastic bone formation with abnormal structure and instability
Osteoclasts are responsible for bone…
Bone resorption
Osteoblasts are responsible for bone…
Bone formation
What does microscopic pathology of osteoporosis show?
Symmetric thinning of trabecular and cortical bone (this results in increased risk of fracture of bone)
In primary osteoporosis, risk increases with…
Age
What is Type I osteoporosis?
Postmenopausal- due to estrogen loss (more typical form)
Causes an increase in osteoclastic activity
What is Type II osteoporosis?
Senile- decreased osteoblastic activity
What are the most common bones fractured in osteoporosis?
Hip
Compression fracture of vertebrae
Distal radius (FOOSH)
What are the risk factors for developing osteoporosis?
Aging and positive family history Smoking Alcoholism Decreased estrogen Low body mass index, low calcium diet, lack of weight bearing exercise
What is an endocrine-related secondary cause of osteoporosis?
Increased PTH, DM, Addison’s disease
What is a GI secondary cause of osteoporosis?
Malnutrition
What is a hematologic-related secondary cause of osteoporosis?
Blood cancers
What is a drug-related secondary cause of osteoporosis?
Long-term presnisone usage, heparin, some chemo agents
Which gender has a higher incidence of developing osteoporosis?
Females
What do patients with osteoporosis often present with?
Vertebral compression fractures, kyphotic
What is the textbook patient stereotype of someone with osteoporosis?
Thin, white female with a long term history of smoking, postmenopausal
What kind of test measures bone density?
DEXA scan
What 2 parameters does a DEXA scan report?
T score, Z score
What is a T score?
Reported by a DEXA scan
Bone density measurement compared to a healthy 30 year old’s bone mass (peak)
What is the normal values for a T score?
+1 to -1
What is a Z score?
The number of standard deviations above or below what is normally expected for same age, sex, weight, and ethnic or racial origin
What is an abnormal Z score?
-2 or lower
What does a T score of +1 to -1 indicate?
Healthy bone density
What does a T- score of -1 to -2.5 indicate?
Osteopenia
What does a T-score of -2.5 to -3.0 indicate?
Osteoporosis
What does a T score of -3.0 and lower indicate?
Severe osteoporosis
What is the difference between Rickets and Osteomalacia?
Same disease preocess but Rickets technically describes children and osteomalacia technically describes adults
What is the disease process in Rickets/osteomalacia?
Mineralization of osteoid is decreased while bone mass stays normal- results in bowing of legs
Vitamin D deficiency/ phosphate deficiency
What is Rickets?
Affects the growing bones of children
It is the inadequate mineralization of osteoid matrix leading to the overgrowth and distortion of epiphyseal cartilage
What does osteomalacia affect?
Newly formed bone matrix in adults
What is osteomyelitis?
Infection of the bone
How is osteomyelitis spread?
Hematogenous spread, contiguous spread
How is osteomyelitis more commonly spread in children?
Hematogenous
What is the most common causative agent in the hematogenous spread of osteomyelitis?
Staph aureus
How is osteomyelitis more commonly spread in adults?
More common to have contiguous spread in adults
Ex- diabetic foot wound, staph is common but can be polymicrobial
True or False osteomyelitis can be either chronic or acute
True- osteomyelitis can be chronic or acute
What are the clinical findings in osteomyelitis?
Pain, warmth of area affected
Fever can be present but is often absent
What labs are you going to see in osteomyelitis?
Elevated ESR, CRP
Elevated platelet count
What radiographic findings are you going to see in osteomyelitis?
Destruction of bone
Periosteal edema
How is the diagnosis of osteomyelitis made?
Blood cultures
Biopsy of bone
(Superficial cultures are not reliable)
What is the treatment for osteomyelitis?
Long term IV antibiotics targeted to organism +/- surgical debridement
How does osteomyeltitis result in ischemia of bone?
Infection lifts periosteum of bone, which impairs blood flow, resulting in ischemia
What is a sequestrum?
A dead bone fragment (in osteomyelitis)
What is an involucrum?
New bone growth around the sequestrum (in osteomyelitis)
What is a Brodie’s abscess?
Residual abscess surrounded by bone growth
Generally speaking, what is arthritis?
Inflammation of the joint
What can be done to help differentiate between infectious and inflammatory arthritis?
Synovial fluid anaylsis
What is the synovial fluid analysis going to indicate in a normal joint?
Clear appearance <200 WBCs <25 PMNs 95-100% serum glucose No crystals
What is a synovial fluid analysis going to indicate in a joint with non-nflammatory arthritis?
Appearance- clear <400 WBCs <25 % PMNs 95-100% serum glucose level No crystals
What is the synovial fluid analysis going to indicate in a joint with an acute gout attack?
Appearance- turbid 2000-5000 WBCs >75% PMNs 80-100% serum glucose level Negative birefringence needle-like crystals
What is the synovial fluid analysis going to indicate in a joint with pseudogout?
Turbid appearance 5000-50,000 WBCs >75% PMNs 80-1000% serum glucose level Positive birefringence rhomboid crystals
What is the synovial fluid analysis in a joint with septic arthritis?
Purulent/ turbid appearance >50,000 WBCs >75% PMNs <50% serum glucose level No crystals
What is the synovial fluid analysis in an inflammatory process such as RA?
Turbid appearance 5,000-50,000 WBCs 50-75% PMNs Approx 75% serum glucose level No crystals
What is the most common degenerative joint disease in people over the age of 65?
Osteoarthritis
What joint disease is attributed to “wear and tear” ?
Osteoarthritis
What is the mechanism of disease in osteoarthritis?
Progressive loss of cartilage in the joint space
What type of joints are impacted by osteoarthritis?
Weight bearing joints
What do microscopic findings show in osteoarthritis?
Loss of cartilaginous staining (loss of proteoglycans), loss of chondrocytes
What causes the inflammation in osteoarthritis?
Fibrillation and splitting of cartilage surface- allows for synovial fluid infiltration, which leads to inflammation
What leads to erosion of open bony surface in osteoarthritis?
Granulation tissue and fibrosis replace cartilage, which leads to erosion of open bony surface
What causes a limitation of range in motion in joints with osteoarthritis?
Osteophyte formation- reactive new bone limits ROM of joint
What are examples of osteophytes?
Heberden node- distal interphalangeal joint
Bouchard node- proximal interphalangeal joint
What are the clinical findings in osteoarthritis?
Morning stiffness worsening throughout the day
Joint pain, usually unilateral
Crepitus on exam
Pain and tenderness on exam
What radiologic findings will you see in osteoarthritis?
Joint space narrowing
Subchondral sclerosis and cysts- synovial fluid leaks into defects in cartilage
Osteophytes
What is infectious arthritis?
Acute or chronic infection of joint
What is infectious arthritis caused by?
Direct seeding of bacteria
What types of bacteria causes infectious arthritis?
Staph
Neisseria gonorrhea
Chlamydia- reactive arthritis (Reiter’s syndrome)
Strep pneumoniae
What is Reiter’s syndrome?
Reactive arthritis
Caused by chlamydia
Affects joints, eyes, urethra
What happens to the joint space in infectious arthritis?
Edematous and neutrophilic infiltration of the synovial space and fluid
What happens to the joint space in infectious arthritis?
Edematous and neutrophilic infiltration of the synovial space and fluid
How is the diagnosis of infectious arthritis made?
Clinical exam
Synovial fluid analysis and culture
What is the treatment for infectious arthritis?
Antibiotic treatment directed at causative organism
What is RA?
Chronic progressive, inflammatory disease
Collagen vasculature disorder
Is the etiology of RA known or unknown??
Unknown
What is the genetic prevalence in RA?
HLA-DR4
HLA-DR1
What is the female to male prevalence in RA?
3:1 female to male
What are the clinical features of RA?
Morning stiffness for longer than 1 hour
3 or more affected joints
Symmetric involvement of joints
Constitutional symptoms- fever, weight loss, fatigue
Warm, tender joints with swan neck deformity, Dupuytren’s contracture, and boutonnière deformity
What is the Felty syndrome triad?
Leukopenia
Splenomegaly
RA
What do the microscopic features in RA show?
Progressive, villous hypertrophy of synovalis secondary to fibrinous swelling
In chronic RA, what replaces acute inflammatory reactions?
Fibrosis eroding of the cartilaginous surface of the joints
What do the x-rays of RA show?
Osteopenia
Narrowing of joint space
What joints are affected in osteoarthritis? RA?
Osteoarthritis- weight-bearing- hips, knees, PIP, DIP
RA- MCP, PIP, feet, wrists, ankles, elbows, knees
How long does morning stiffness last in osteoarthritis? RA?
Osteoarthritis- less than 30 minutes
RA- longer than 1 hour
What are the symptoms in osteoarthritis, RA?
Osteoarthritis- pain with movement, better with rest
RA- stiffness and pain worse with inactivity
What will the physical exam show is osteoarthritis, RA?
Osteoarthritis- heberden and Bouchard nodes
RA- rheumatoid nodules, radial deviation of wrist, ulnar deviation of phalanges
Ankylosing Spondylitis is sero____ spondyloarthropathy
Seronegative
What percentage of people with ankylosing spondylitis have the HLA B27 gene?
90%
Ankylosing spondylitis preferentially involves….
Vertebral column, SI joints
What is the onset of ankylosing spondylitis?
2nd and 3rd decade of life (teens-20s)
What is the clinical presentation of ankylosing spondylitis?
Gradual onset of back pain
Loss of mobility
Gout is arthritis due to what depositing in the joint space?
Uric acid crystals
What are 90% or primary cases of gout due to?
Increased production or decreased excretion
What are some secondary causes of gout?
Cell turnover from leukemia
Chronic renal disease
What are some risk factors for gout?
Alcohol, obesity, thiazide diuretics
What are tophi?
Aggregates of urates rimmed with macrophages, lymphocytes, and giant cells- found in joints and ligaments, can cause a chronic tophaceous arthritis
What is the pathology behind gout?
Urate crystals (needle shaped) precipitated in the synovium, crystals are chemotactic for neutrophils/ activate complement, acute arthritis occurs as a result of neutrophilic infiltrate with uric acid crystals in the joint
Where do 50% of first attacks of gout occur?
At the first metatarsophalangeal joint (big toe, very painful)
Pseudogout occurs in patients with…
Degenerative joint disease
Pseudogout mimics….
Osteoarthritis symptoms
What kind of crystals are found in Pseudogout?
Calcium pyrophosphate crystals- rhomboid
Paget disease is also known as…
Osteitis deformans
What is Paget disease?
Excessive osteoblastic bone formation with abnormal structure and impaired stability
Paget disease has an increase in incidence after the age of…
40
What is the stereotypical patient with Paget Disease?
Caucasian, men more than women, older than 40
The early phases of Paget disease are asymptomatic/ symptomatic
Asymptomatic
What are the clinical features of Paget disease?
Enlargement of head bones, headache, deafness, visual disturbances and deformation/tenderness of long bones
What are the radiologic findings in Paget disease?
Pathologic fracture= chalk stick fracture (cross fracture of long bones)
Thick course cortex of bone
What are the lab findings in Paget disease?
Elevated serum alkaline phosphatase
What are 3 malignant primary tumors of bone?
Osteosarcoma
Ewing sarcoma
Chondrosarcoma
What is the most common tumor arising within the bone?
Multiple myeloma
Which are more common…benign or malignant tumors in the bone?
Benign tumors are 100X more common than malignant
What is the most common malignant bone tumor?
Osteosarcoma
Which bone cancer occurs mostly in children and adolescents?
Osteosarcoma
What are the common sites of an osteosarcoma?
Metaphysical areas adjacent to knee and shoulder
What do X-rays show in osteosarcoma?
Localized lytic or osteoblastic lesions with fuzzy borders and prominent subperiosteal reactive bone formation (Codman triangle)
What do the microscopic findings in an osteosarcoma reveal?
Osteoblastic lesion with lacy osteoid deposition
Where do osteosarcomas commonly metastasize to?
The lung
What is the second most common tumor of children?
Ewing sarcoma
What does an Ewing sarcoma often present as?
Fever and pain mimicking an inflammatory process- often misdiagnosed as osteomyelitis
How is the diagnosis of an Ewing sarcoma confirmed?
Biopsy
What bones are most commonly affected by Ewing sarcomas?
Long bones- humerus, tibia and femur
Where do Ewing sarcomas commonly metastasize to?
Lungs, brain, and skull
A chondrosarcoma arises from…
Cartilage
What age is affected by chondrosarcoma?
40-60s, peak of incidence in 60s
What bones do chondrosarcomas usually affect?
Central portions of skeleton- shoulder, pelvis, proximal femur and ribs
What does radiology show in a chondrosarcoma?
Bulky osteodestructive lesion with characteristic pattern of calcification (popcorn)
Where do chondrosarcomas commonly metastasize to?
Lungs
How are malignant soft tissue tumors spread?
Hematogenous spread, classified by tissue derivation
What type of malignant soft tissue tumor is the most common?
Malignant fibrous histiocytoma- deep fascia, skeletal muscle, and retroperitoneal space
Where do liposarcomas occur?
Deep subcutaneous tissue of thighs, abdomen, and retroperitoneum
What age group experiences the most liposarcomas?
Greater than age 50
Who is most susceptible to Rhabdomyosarcoma and what type of tissue does it involve?
Children and adolescents, skeletal muscle
What type of tissue is affected by Leiomyosarcomas?
Smooth muscle, uterus, and GI
What type of tissue is affected by Neurofibrosarcomas?
Peripheral nerves
