MSK Flashcards
Achondroplasia is an _______ _________ inherited condition that involves impaired cartilage proliferation in the growth plate. It is due to an ___________ (activating/inactivating) mutation in _______; most mutations are sporadic
Autosomal dominant; Activating; FGFR3
[Clinical features include short extremities with normal-sized head and chest. Mental function, life span, and fertility are not affected]
Osteogenesis imperfecta is a congenital defect of bone formation resulting in weak bone. It is most commonly due to an _____ ______ inherited defect in ___________ synthesis. Clinical features include multiple fractures of bone, blue sclera, and ________ loss
Autosomal dominant; type I collagen; hearing
[type ONE collagen in bONE]
What causes blue sclera in osteogenesis imperfecta?
Exposure of choroidal veins
Inherited defect of bone resorption resulting in abnormally thick, heavy bone that fractures easily. Clinical features include fractures, anemia, thrombocytopenia, and leukopenia with extramedullary hematopoeisis in the spleen and liver, vision and hearing impairment, hydrocephalus, and renal tubular acidosis
Osteopetrosis
myelophthisic process
Osteopetrosis is due to poor _______ function and there are multiple genetic variants. One common example is a _________ mutation, which results in lack of acidic environment required for resorption of bone
Osteoclast; carbonic anhydrase II
Treatment for osteopetrosis
Bone marrow transplant
[replaces hematopoietic stem cells with healthy ones that are able to generate healthy monocytes/osteocytes/osteoclasts]
Pigeon breast deformity, frontal bossing, rachitic rosary, and bowing of the legs
Rickets (pediatric vitamin D deficiency)
[Rachitic rosary = Deposition of osteoid at costochondral junctions]
What changes occur in serum calcium, serum phosphate, PTH, and alkaline phosphatase in osteomalacia?
Decreased serum calcium
Decreased serum phosphate
Increased PTH
Increased alkaline phosphatase
[whenever there is increased activity of osteoblasts, alkaline phosphatase is increased. Remember that an acidic environment is needed for osteoclasts to resorb bone, and an alkaline environment is needed for osteoblasts to lay down bone]
Loss of trabecular bone mass resulting in porous bone with increased risk of fracture
Osteoporosis
Peak bone mass is reached at roughly age _____ and steadily declines at ~1% per year thereafter.
The 3 factors most important in building up to peak bone are ______, ______, and the _____ receptor inherited from your parents.
The factors important for slowing bone loss after the peak are _____, ______, and _______
30
Diet; exercise; vitamin D
Diet; exercise; estrogen
The most common forms of osteoporosis are _____ and _____
Senile; postmenopausal
[senile because role of age, postmenopausal d/t loss of estrogen]
Clinical features of osteoporosis include bone pain and fractures in weight bearing areas (i.e., vertebra). Bone density is measured using a DEXA scan.
How do serum calcium, phosphate, PTH, and alkaline phosphatase change in osteoporosis?
They all remain normal!
Imbalance between osteoclast and osteoblast function usually seen in late adulthood; etiology is unknown but is possibly viral. Clinical features include bone pain, increased hat size, hearing loss, lion-like faces, and isolated increase in alkaline phosphatase
Paget disease of bone
T/F: Paget disease of bone is a localized process involving one or more bones; does not involve entire skeleton
True
What are the 3 stages of Paget disease of bone in order?
- Osteoclastic
- Mixed osteoblastic-osteoclastic
- Osteoblastic (mosaic pattern of lamellar bone with cement lines)
[end result is thick sclerotic bone that fractures easily]
An isolated increase in alkaline phosphatase may indicate what pathologic process in the MSK system?
Paget disease of bone
2 primary treatments for Paget disease of bone
Calcitonin (inhibits osteoclasts)
Bisphosphonates (promotes apoptosis of osteoclasts)
2 major complications associated with Paget disease of bone
High-output cardiac failure (due to formation of AV shunts)
Osteosarcoma (malignant tumor of osteoblasts)
Osteomyelitis is an infection of the marrow space and bone, usually occurring in children. It is most often bacterial and arises due to ______ spread. Clinical features include bone pain with fever and leukocytosis. X-ray shows lytic focus surrounded by sclerosis. Diagnosis is made by _________
In terms of bone areas affected, osteomyelitis usually seeds the _____ in children, and the _______ in adults
Hematogenous; blood culture
Metaphysis; epiphysis
The most common cause of osteomyelitis is S.aureus. N.gonorrheae can also cause it, particularly in sexually active young adults. ________ is the most common cause in sickle cell disease
Salmonella
Common cause of osteomyelitis in a diabetic or IV drug abuser
Pseudomonas
Common cause of osteomyelitis in a pt exposed to dog or cat bite/scratch
Pasteurella
Cause of osteomyelitis commonly affecting the vertebra
TB
Avascular necrosis is an ASEPTIC ischemic necrosis of bone and bone marrow. Complications include osteoarthritis and fracture. What are some common causes of this condition?
Trauma or fracture
Steroids
Sickle cell — classic example is dactylitis
Caisson disease — nitrogen gas emboli that lodge in bone
An osteoma is a benign tumor of bone usually arising from surface of _______ bones; often associated with ______ syndrome
Facial; Gardner
Familial adenomatous polyposis, fibromatosis in the retroperitoneum, osteomas of the facial bone
Gardner syndrome
[remember that fibromatosis is a proliferation of fibroblasts that locally destroys tissue]
Benign tumor of osteoblasts surrounded by rim of reactive bone occurring in young adults <25 y/o and arises in cortex of long bones (e.g., femur)
Osteoid osteoma
Osteoid osteoma arises in the cortex of long bones (e.g., femur), most commonly in the region of the ______
Diaphysis
19 y/o presents with bone pain in the thigh that resolves with aspirin; imaging reveals a bony mass with a radiolucent (osteoid) core
Osteoid osteoma
Osteoblastoma is similar to osteoid osteoma as they are both tumors of osteoblasts. What are the 3 key differences that distinguish osteoblastoma?
Larger (>2 cm)
Arises in vertebrae (vs. diaphysis with osteoid osteoma)
Presents as bone pain that does NOT respond to aspirin
Most common benign tumor of bone
Osteochondroma
Osteochondroma is a tumor of bone with an overlying cartilage cap; it arises from a lateral projection of the ______ ______. The medulla of the bone is continuous with the medulla of this projection. An important complication to note is that the overlying cartilage of an osteochondroma can transform into a _________
Growth plate; chondrosarcoma
Malignant proliferation of osteoblasts arising in the METAPHYSIS of long bones, usually the distal femur or proximal tibia. It presents as pathologic fracture or bone pain with swelling
Osteosarcoma
Osteosarcoma has a peak incidence in teenagers; less commonly seen in the elderly. Risk factors include familial ______ (particular risk factor for kids/teens), and _____ disease and _______ exposure (particular risk factors in elderly)
Rb; Paget; radiation
Osteosarcoma classically forms in the region of the ________. On imaging it shows a periosteal lift and Codmans angle with sunburst appearance. On biopsy it would show large pleomorphic cells (aka high grade malignant cells) producing _______
Metaphysis; osteoid
Bone tumor comprised of multinucleated giant cells and stromal cells occurring in young adults
Giant cell tumor
Giant cell tumors arise in the _____ of long bones, usually distal femur or proximal tibia. It has a _________ appearance on X-ray. It is a locally aggressive tumor and it may recur
Epiphysis; soap-bubble
Malignant proliferation of poorly differentiated cells derived from neuroectoderm; arises in diaphysis of long bones inside the medullary cavity, usually in male children and sometimes accompanied by fever. Shows ‘onion-skin’ appearance on x-ray and is associated with t(11;22) translocation
Ewing sarcoma
[biopsy shows small round blue cells with lymphocytes — don’t confuse with lymphoma or osteomyelitis which do not have associated translocation]
Ewing sarcoma is a malignant proliferation of poorly-differentiated cells derived from _______. It arises in the _______ of long bones, usually in male children and is associated with translocation ______
Neuroectoderm; diaphysis; t(11;22)
T/F: ewing sarcoma often presents with metastasis but is responsive to chemotherapy
True
What is the only tumor we need to know for boards that grows from the epiphysis of long bones?
Giant cell tumor
Benign tumor of cartilage that usually arises in medulla of small bones of hands and feet
Chondroma
Malignant cartilage forming tumor that arises in medulla of pelvis or central skeleton
Chondrosarcoma
Metastatic tumors are more common than primary tumors of bone; they usually result in ______ (punched-out) lesions, however _____ _____ classically produces osteoblastic (sclerotic) lesions
Osteoclastic; prostatic carcinoma
Articular cartilage in synovial joints is made up of type ____ cartilage
Type II cartilage
Pathologic features of degenerative joint disease include disruption of the cartilage that lines the articular surface, _______ of the subchondral bone, and ______ formation resulting in thickening of the joint (classically arises in the DIP and PIP joints of the fingers where it is called ____ and ______ nodes)
Eburnation; osteophytes; heberden; bouchard
Rheumatoid arthritis is a chronic, systemic autoimmune disease more commonly seen in middle-aged women. It is associated with HLA ____.
It is characterized by involvement of joints. The hallmark is synovitis leading to ______ formation (thick layer of inflamed granulation tissue). This leads to destruction of cartilage and ankylosis of the joint
HLA-DR4
Pannus
Clinical features of RA include joint space narrowing, loss of cartilage, and osteopenia, as well as possible fever, malaise, weight loss, and myalgias. Other features include rheumatoid nodules, baker cyst, and LAD.
What are 2 complications affecting the cardiopulmonary system?
Vasculitis
Pleural effusions and interstitial lung fibrosis
Lab findings in RA include a _____ autoantibody against ________ (rheumatoid factor).
Synovial fluid contains ______ and _____ protein
IgM; Fc portion of IgG
Neutrophils; high
2 main complications of RA include ____ of chronic disease and secondary _____
Anemia; amyloidosis (AA amyloid)
Seronegative spondyloarthropathies lack rheumatoid factor, affect the axial skeleton, and are associated with HLA ___
HLA-B27
Ankylosing spondyloarthritis involves the SI joints and spine, presents with low back pain, and involvement of the vertebral spine leads to fusion of vertebrae. Additional systemic features include ____ and ____
Uveitis; aortitis
[aorititis can lead to aneurysm formation as well as aortic regurgitation]
Arthritis, urethritis, and conjunctivitis arising in young male adult weeks after GI or C.trachomatis infection
Reiter syndrome
3 features of Reiter syndrome
Arthritis
Urethritis
Conjunctivitis
[cant see cant pee cant climb a tree]
Psoriatic arthritis is seen in 10% of cases of psoriasis. It involves axial and peripheral joints, classically the _____ of the hands and feet (‘sausage’ finger or toe)
DIP
Most common overall cause of infectious arthritis is ________, which is more commonly seen in young adults. The 2nd most common cause is _________, seen in older children and adults
N. Gonorrhoeae; S.aureus
Inflammatory disorder of the skin and skeletal muscle with unkonwn etiology; some cases are associated with carcinoma (e.g., gastric carcinoma). Characterized by bilateral proximal muscle weakness; distal involvement can develop late in disease
Dermatomyositis
Describe the typical rash associated with dermatomyositis
Rash of upper eyelids (heliotrope rash); malar rash may be seen — don’t confuse with lupus!
Red papules on the elbows, knuckles, and knees (Grotton lesions)
Lab findings in dermatomyositis include increased creatinine kinase, positive ANA and ___________ antibody.
Biopsy findings include ______ inflammation with _____ cells, and perifascicular atrophy.
Treatment is _______
Anti-jo-1
Perimysial; CD4+
Corticosteroids
[note difference from polymyositis which is ENDOmysial inflammation with CD8+ T cells; remember that perimysium is closer to skin — dermatomyositis]
Inflammatory disorder of skeletal muscle characterized by endomysial inflammation consisting of CD8+ T cells with necrotic muscle fibers
Polymyositis
[resembles dermatomyositis clinically but skin is not involved]
X-linked muscular dystrophy is a degenerative disorder characterized by muscle wasting and replacement of skeletal muscle by _________. It is caused by deletions of _______, which links muscle cytoskeleton to ECM
Adipose; dystrophin
[aka Duchennes muscular dystrophy]
X-linked muscular dystrophy presents as proximal muscle weakness at 1 year of age. It progresses to involve distal muscles. Initial calf ________ is characteristic findings. Labs show elevated creatinine kinase. Death results from cardiac or respiratory failure, often due to the common involvement of the _______
Pseudohypertrophy; myocardium (diaphragm may also be involved)
Becker muscular dystrophy is due to a _______ dystrophin that results in clinically milder disease
Mutated
[as opposed to deleted in DMD]
Myasthenia gravis is more commonly seen in women and involves autoantibodies against what?
Postsynaptic ACh receptor at NMJ
In myasthenia gravis, there is muscle weakness that worsens with use and improves with rest. It classically involves the eyes leading to ptosis and diplopia.
Symptoms improve with _________ agents. MG is also associated with ______ hyperplasia or ______
Anticholinesterase; thymic; thymoma
[removal of thymus —> improvement]
Lambert-Eaton syndrome arises as a paraneoplastic syndrome, most commonly due to ________________. It involves antibodies against ________________
Small cell carcinoma; presynaptic calcium channels at the NMJ (leads to impaired ACh release)
[improves with resection of cancer]
How are clinical features of Lambert Eaton different from MG?
With lambert eaton, there is proximal muscle weakness that IMPROVES with use
The eyes are usually spared
Anticholinesterase agents do not improve symptoms
Most common malignant soft tissue tumor in adults
Liposarcoma
Liposarcoma is a malignant tumor of adipose tissue; the characteristic cell is the _____
Lipoblast
Rhabdomyoma is a benign tumor of skeletal muscle. A cardiac rhabdomyoma is associated with ____ ___
Tuberous sclerosis
Most common malignant soft tissue tumor in children
Rhabdomyosarcoma
Rhabdomyosarcoma is a malignant tumor of skeletal muscle. The characteristic cell is the _______, which is ______-positive. The most common site is head and neck, however the _____ is a classic site in young girls
Rhabdomyoblast; desmin; vagina (sarcoma botryoides)
