Flashcards in Musculoskeletal, skin, connective tissue pathology Deck (36)
What is achondroplasia?
This is the failure of longitudinal bone growth through endochondral ossification leading to short limbs.
Typically due to ACTIVIATION OF FIBROBLAST GROWTH FACTOR RECEPTOR FGFR3 inhibiting chondrocyte proliferation.
autosomal dominant and most common cause of dwarfism.
What DEXA scan will show primary osteoperosis
Loss of the spongey trabecular bone is shown with a DEXA T score of < -2.5
Long term steroid use, anticonvulsants, anticoagulants and thyroid replacement therapy can cause this. `
What is denosumab?
A monoclonal body directed againt Rank-L to help with osteoperosis.
What is an X-ray conveying when they tell you there is a "Bone in Bone appearance"
Osteopetrosis where there is ineffective osteoclast performance.
What causes rickets?
Vitamin D deficiency due to defective mineralization/calcification of osteoid.
Less vitamin D means less serum calcium
What are the two forms of benighn bone tumors for the exam?
Giant cell tumor - soap bubble lesions
Osteochondroma with a cartilaginous exostosis. (Most common benign tumor).
Where does osteosarcoma typically localize and what trait will it exhibit?
Localizes areound the metaphisis of long bones espexially around the knee and exibits codmans triangle.
Where does ewing sarcoma show up and what does it display?
Common in the diaphysis of long bones, pelvis, scapula, and ribs.
Anaplastic small blue cell malignant tumors with onion skinning.
What translocation is ewings sarcoma most commonly related to?
What is the difference between osteoarthritis and rheumatoid arthritis?
Osteo is due to over use found typically in weight bearing joints. Subchondral cysts with sclerosis and synovitis seen here.
Rheumo is a type III and IV hypersensitivity reacton. Pannus and rheumatoid nodules with ulnar deviation and swan neck deformities found here.
What occurs in Sjorgen syndrome?
Autoimmune disorder causing the destruction of exocrine glands.
Results in antinuclear antibodies SS-A and or SS-B.
Look for swollen bilateral parotid glands.
What color will gout crystals appear under paralell light?
Will be yeLLow under ParaLLel light.
Pseudo gout will be Blue under parallel light.
Cant even climb a tree
classic triad of Reiters syndrome.
Post chlamydia infections.
ankylosing spondylitis resulting in chronic inflammatory dsease of the spine and sacroiliac joints.
Pencil in cup appearance.
Libman Saccs endocarditis
Wart like growths in the heart secondary to systemic lupus erythematosus.
Black female elevated ACE evels and elevated CD4/CD8 ratio. Enlarged lymph nodes.
Associated with restrictive lung disease.
Treat it with steroids.
Muscle weakness progresses with use.
Myasthenia gravis, autoantibodies against presynaptic Ach receptors.
Proximal muscle weakness, autonomic symptoms that improve with muscle use.
Lambert Eaton myasthenic syndrome.
Autoantibodies to presynaptic calcium channels leading to decreased Ach release.
Name the dermal layers from the surface to the base.
"Californians Like Girls in String Bikinis"
What does the adherens junction in the epithelial cells contain?
What protein type holds epithelial cells to the basal membrane?
Hemidesmosomes connect keratin in basal cells to underlying basement membrane. Autoantibodies creat bullous pemphigoid.
What causes albinism?
Lack of melanin production due to a faulty tyrosinase nzyme or tyrosine transport.
What causes vitiligo?
Autoimmune destruction of melanocytes.
What type of hypersensitivity is contact dermatitis?
A type IV hypersensitivity leading to lesions at sights of contact.
What is the most common form of skin cancer?
Basal cell carcinoma!
Look for "Palisading nuclei"
Precursor to squamous cell carcinoma.
Which form of skin cancer is related to the presence of keratinic pearls?
Squamous cell carcinoma.
The chemical LTB4 serves what purpose?
It is a form of neutrophil chemotaxis produced in the leukotrien pathway.
What is the purpose of the chemical PGI2?
Inhibits platelet aggregation and is formed through the prostacyclin route.
"Think platelet gathering inhibitor"
How does allopurinol work?
Blocks xanthine oxidase after being converted to alloxanthine.
How does febuxostat work?
Inhibits xanthine oxidase.
How does pegloticase work?
Recombnant uricase that catalyzes urc acid to allantoin.
How does probenicid work?
Inhibits reabsorption of uric acid in the proximal convuluted tubule.
Also inhibits penicillin reabsorption!!!
How does Colchicine work?
Binds to tubulin inhibiting mucrotubule polymerization inhibitin neutrophil chemotaxis.