USMLE-related
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Selective estrogen receptor modulators
· 1 мин чтения
Drugs Tamoxifene Raloxifene MOA Competitive inhibitor of estrogen binding Mixed agonist/antagonist action Indications Prevention of breast cancer in high-risk patients Tamoxifene: adjuvant treatment…
Pharmacokinetic parameters
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Parameter Equation Note Half-life Vd x 0.7 / CL Steady-state concentration is achieved in 4-5 half-lives Maintenance dose C ss x CL x dosing interval Maintenance dose is decreased in patients with…
Hypersensitivity pneumonitis
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Etiology Immunologic response to inhaled antigen (mold, animal protein and etc.) Clinical presentation Acute Chronic Abrupt-onset fever, chills, cough, dyspnea, fatigue, leukocytosis Progressive…
Syphilis diagnosis
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Type Note Nontreponemal (RPR, VDRL) - Antibody to cardiolipin-cholesterol-lecithin antigen- Lower sensitivity in early infection Treponemal (FTA-ABS, TP-EIA) - Antibody to treponemal antigens -…
Autism spectrum disorder
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Clinical features Deficits in social communications & interactions with onset in early development Sharing of emotions or interests Nonverbal communication Developing & understanding…
Diuretics
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Diuretic effects on total body electrolyte levels Diuretic type Na+ K+ HCO3- Ca2+ Uric Acid Loop (eg. furosemide) ↓↓↓ ↓↓ ↑↑ ↓ ↑ Thiazide (eg, HCTZ, metalazone) ↓↓ ↓ ↑ ↑ ↑ Potassium sparing (eg,…
Cavernous sinus thrombosis
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The infection can communicate in a retrograde fashion into the cavernous sinus through the valveless facial venous system. Most common pathogens: Staph aureus Streptococci Fungal, like Mucor rhizopus
Amino acids
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Glucogenic Ketogenic Both Aspartate Lysine Tyrosine Asparagine Leucine Phenylalanine Arginine Threonine Proline Isoleucine Histidine Tryptophan Glutamine Glutamic acid Methionine Valine Glycine…
Acute rheumatic fever
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Epidemiology Endemic in developing countries Pathogenesis Occurs 2-4 weeks after acute group A streptococcal pharyngitis. Molecular mimicry: Anti-streptococcal antibodies attack cardiac &…
Hypothalamic nuclei
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Nucleus Function Ventromedial Mediates satiety, destruction leads to hyperphagia Lateral Mediates hunger; destruction leads to anorexia Anterior Mediates heat dissipation; destruction leads to…
Shocks
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Parameter Hypovolemic shock Cardiogenic shock Obstructive shock Distributive Shock CVP (right-sided preload) ↓ ↑ ↑ ↓ PCWP (left-sided preload) ↓ ↓ ↓* ↓ Cardiac index (LV output) ↓ ↓ ↓ ↑** SVR ↑ ↑ ↑ ↓…
Retinitis pigmentosa
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Etiology Genetic dystrophy Progressive retinal degeneration (photoreceptors, pigmented epithelium) Clinical features Loss of rods: Night blindness Peripheral visual field loss Loss of cones:…
Causes of hypokalemia
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Decrease intake Starvation, anorexia Intracellular translocation Insulin (eg, treatment of DKA, refeeding syndrome) B-adrenergic activity Pharmacologic (eg, albuterol, dobutamine) Stress-induced (eg,…
Henoch-Schönlein purpura (lgA vasculitis)
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Pathogenesis Deposition of lgA immune complexes in small vessels activate complement Neutrophilic inflammation & vascular damage Often follows an upper respiratory infection Clinical…
Cryptosporidiosis
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Pathogenesis Fecal-oral transmission (eg., contaminated water, animal contact) graph LR A[Oocyte ingestion] --> B[Sporozoite attachment to intestinal epithelium] B --> C[Intraluminal meront…
Bacillus anthracis
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graph LR A[Polypeptide capsule composed of D-glutamic acid] --> B[Antiphagocytic]
Lung transplant rejection
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Type Onset Etiology Pathophysiology Hyperacute Minutes to hours Preformed host antibodies to donor ABO or HLA Neutrophilic infiltration with fibrinoid necrosis and thrombosis Acute ≤ 6 months…
Candida chiorioretinitis & endophthalmitis
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Epidemiology graph LR A[Transient/persistent fungemia] --> B[Hematogenous dissemination to the choroid] B --> C[Invasion of the retina & fluid chambers] Risk factors: Indwelling central…