MSK 2 Flashcards
What is the MOA of Cidofovir? What does this drug treat?
A nucleotide analog that is converted to active triphosphate by cellular kinases w/o depending on virally encoded kinases. It can treat VZV, w/c is acyclovir-resistant.
What do nucleoside analogs need to activate?
Nucleoside analogs (acyclovir, valacyclovir, famciclovir, ganciclovir) need viral phosphorylating kinases like thymidine kinase to become active triphosphates.
What vasculitides of medium vessels is commonly associated w/ Hepatitis B infection?
Polyarteritis nodosa presents as transmural inflammation of arterial wall w/ fibrinoid necrosis. It affects arteries of any organ except the lungs.
Cherry hemangioma vs Strawberry hemangioma
[appearance, age]
> Cherry: bright red, papular lesions, superficial, benign tumor in adults, don’t regress spontaneously.
Strawberry: bright red compressible plaques, benign tumors of kids, appear in first weeks of life and regress by age 5-8.
How does radial head subluxation occur in children?
There is sudden traction on the outstretch and pronated arm of the child (“nursemaid’s elbow”). The annular ligament may be torn and displaced. Affected kids might not show distress unless they try to move their arm.
What is the presentation of a child with rickets, both before ambulation and when weight-bearing?
Before ambulation, the child may have frontal bossing, craniotabes, costochondral junction widening from cartilage overgrowth. Once the kid is weight-bearing, there may be lateral femoral and tibial bowing (genu varum).
Why should patients be evaluated for latent TB if they’re going to take etanercept (TNF-alpha inhibitor)?
Etanercept acts as a decoy receptor for TNF-alpha. This can promote reactivation of latent TB since TNF-alpha is needed to sequester mycobacteria w/in the granuloma.
Why are thiazide diuretics recommended in treatment for osteoporosis?
Thiazides inc. Ca absorption in DCT, and this is associated w/ inc. bone mineral density. This is useful for tx of HTN in patients at risk for osteoporosis (postmenopausal women).
What are the side effects of Methotrexate?
Methotrexate preferentially inhibits the growth of rapidly dividing cells. It’s effective for inflammatory and neoplastic cells, but cells of the liver, bone marrow, hair, and GIT epithelia are also rapidly dividing – GI ulcers, pancytopenia, hepatitis and cirrhosis, alopecia.
What is the presentation of Fibromyalgia?
Fibromyalgia presents w/ widespread MSK pain, fatigue, and neuropsychiatric disturbances. It’s characterized by abnormal central processing of painful stimuli, though the actual etx is unknown. Aerobic exercise helps to improve pain.
What is the pathogenesis for Psoriasis that causes it to manifest the “Auspitz sign?”
> Auspitz sign: pinpoint bleeding when scale is removed from plaque due to dilated vessels just above dermal papillae.
CD4+ cells activate CD8+ cells in epidermis after interacting w/ APCs in the skin. The resulting release of cytokines and keratinocyte GFs cause keratinocyte proliferation, inflammation, and angiogenesis.
How is the presentation of Drug-induced lupus different from SLE? What drugs cause DILE?
Lacks the usual skin manifestation (malar rash) and is rarely associated w/ neuro or renal complications. It also has the specific Anti-histone antibodies.
>Procainamide, Isoniazid, Hydralazine, Minocycline, TNF-alpha inhibitors (Etanercept)
What is the treatment for androgenetic alopecia?
Androgens (DHT) are central to the pathogenesis. 5-alpha reductase inhibitors, w/c inhibit conversion of testosterone to DHT, can minimize progression.
What is the pathogenesis of Polymyositis?
> Overexpression of MHCI on sarcolemma – infiltration of CD8+ cells in endomysium – myocyte damage.
Presents w/ symmetrical proximal muscle weakness, possible triggered by viral antigens.
Why are bisphosphonates useful as a therapy for osteoporosis?
Chem structure is similar to pyrophosphate, so they attach to hydroxyapatite binding sites on bone – osteoclasts resorb bone and take up bisphosphonates – osteoclasts can’t adhere to bony surface and continue resorption, osteoclast apoptosis also induced – dec. bone loss, inc. bone density.
