USMLE UWorld Step 1 TestBank With
complete solution 100% verified correct
Nitroglycerin (nitrates) - symptomatic relief in chronic stable angina - MOA? Adverse
effects? - Predominantly a *venodilator*, also some arterial vasodilation - decreases
both preload & afterload (stroke volume maintained) -- NO ^cGMP, decreasing
intracellular Ca, dephosphorylating myosin light-chain, relaxing vascular smooth muscle
-- headaches, flushing, lightheadedness, hypotension, reflex tachycardia ---
nitroprusside can cause cyanide toxicity
First line treatment for essential tremor - Propranolol
RAS signaling protein is active when bound to - GTP (ex: constitutively activated
KRAS implicated in colon cancer)
Mullerian Aplasia - No upper (therefore short) vagina, variable uterine development.
46,XX females with normal ovaries and 2ndary sexual characteristics
Physician's priority in domestic violence case - safety (emergency plan? safe place
to go?) - don't confront denial or pressure patient to disclose abuse or leave
Stroke in what brain area would cause complete contralateral SENSORY loss -
Thalamus
Cause of lacunar infarcts - small vessel occlusion due to lipohyalinosis and
microatheroma formation -> lenticulostriate arteries <- uncontrolled HTN & DM
Cocaine MOA - inhibits presynaptic reuptake of NE,D,S (increased sympathetic
activity); vasoconstrictor (cause MI, sudden death)
Mutations associated with thyroid cancer: medullary vs follicular vs anaplastic -
Medullary (RET), Follicular (RAS), Anaplastic (p53)
Dynein vs Kinesin - molecular motor proteins
(nerve axonal transport direction) - Dynein (periphery->center, + to -, retrograde)
Kinesin (center->periphery, - to +, anterograde)
Negative end Near Nucleus
Positive end Points to Periphery
Treatment of choice for behavioral symptoms of delirium - low dose antipsychotic
(haloperidol)
Adenosine & Dypyridamole - selective vasodilators of all coronary vessels, can
cause coronary steal syndrome (hypoperfusion & worsening of existing myocardial
ischemia)
, Treatment of choice for status epilepticus? (single seizure lasting >5 minutes or
multiple discrete seizures with incomplete recovery between episodes) - IV
benzodiazepine (like lorazepam) ...to stop the seizure, then concurrently begin
phenytoin to prevent recurrence
Pellagra - *Vitamin B3 (Niacin) deficiency - diarrhea, dermatitis, dementia* -
precursor for NAD & NADP (cofactors for many dehydrogenase and reductase
enzymes) - seen in those with poor nutrition (alcoholics) or corn-heavy diets - Niacin
can be synthesized endogenously from *tryptophan*
Stimulation of what nerve will move bulky tongue out of the way in obstructive sleep
apnea? - Hypoglossal
Femoral nerve block (location) - Inguinal crease at lateral border of femoral artery -
numbs anterior thigh, quads, femur, knee
Pudendal nerve block (anatomic landmark / location) for delivery? Presentation of
stretch injury? - Ischial spine tip - for vaginal deliveries
Decreased sensation in perineum and genital area; can cause fecal/urinary
incontinence (pudendal normally controls external sphincters) - although, most common
cause of anal incontinence after childbirth is sphincter damage
Gigantism - hypersecretion of growth hormone from AP; changes mediated by release
of: - insulin-like growth factor 1 (IGF-1) from liver
Toxic component of LPS - Lipid A ... gram-negative sepsis
ACE-inhibitor induced angioedema & dry cough is due to? -- ACEi also decrease GFR
and increase potassium - bradykinin accumulation (vasodilator, increases vascular
permeability; also increases prostaglandin production, irritating bronchi) - normally
broken down by ACE
Lateral ankle sprain due to inversion of plantar-flexed foot most commonly involves: -
anterior talofibular ligament
Anticholinergic toxicity - Atropine & scopolamine (in jimsonweed) competitively
inhibit muscarinic Ach receptors. Blind as a bat, mad as a hatter, red as a beet, hot as a
hare, dry as a bone, full as a flash, fast as a fiddle. REVERSED by cholinesterase
inhibitors (physostigmine).
How does timolol help treat glaucoma? - non-selective beta-blocker diminish
secretion of aqueous humor by ciliary epithelium (decrease IOP) [glaucoma =
progressive peripheral vision loss]
, Ebstein anomaly - Displacement of tricuspid valve leaflets downward into RV,
decreased RV volume, atrialization of RV -- caused by *lithium* teratogenicity, treats
bipolar disorder -- tricuspid regurg & right heart failure
Zellweger syndrome - infantile defective peroxisomal biogenesis (very long chain fatty
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acids and branched chain fatty acids cannot undergo oxidation) - buildup causes
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craniofacial abnormalities, hepatomegaly, neurologic defects, death -- adult version: x-
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linked adrenoleukodystrophy ii
Pulsus paradoxus - Exaggerated drop in systolic blood pressure (>10 mmHg) during
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inspiration -- most commonly seen in pericardial effusion with cardiac tamponade
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Beck's triad = Cardiac Tamponade - Hypotension with pulsus paradoxus, elevated
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jugular venous pressure, muffled heart sounds
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Acute intermittent porphyria - Autosomal dominant, *porphobilinogen (PBG)
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deaminase deficiency* - abdominal pain, neuropsychiatric, reddish-brown urine that
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darkens. Worse with alcohol/smoking. Treat with IV glucose or heme to downregulate
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aminolevulinate (ALA) synthase --- PBG & ALA accumulate, causing symptoms
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Two most common adverse effects of long-term *lithium* therapy (can also cause these
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same effects in a fetus) - Hypothyroidism & nephrogenic diabetes insipidus (lithium =
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bipolar mood stabilizer)
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How to get shit out of the lungs: 3 levels, 3 processes - upper airway -
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coughing/sneezing
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bronchi->terminal bronchioles - mucociliary transport ii ii ii ii
respiratory bronchioles->alveoli - phagocytosis by alveolar macrophages
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2 specific features of Graves disease (TRAb-mediated hyperthyroidism) -
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Ophthalmopathy (proptosis) and pretibial myxedema
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Gerstmann Syndrome - damage/stroke to angular gyrus of dominant (left-sided) parietal
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association cortex (4 signs) - 1. Agraphia (inability to write)
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2. Acalculia (inability to math)
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3. Finger agnosia (inability to identify individual fingers on hand)
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4. Left-right disorientation
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---Nondominant (right-sided) lesions to parietal lobe result in hemi-neglect ii ii ii ii ii ii ii ii
First line treatment for Wilson Disease - Copper chelator (*penicillamine*) "copper
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penny"
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[low ceruloplasmin, Kayser-Fleischer rings, atrophy of basal ganglia]
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First line treatment for iron overdose - Iron chelator (Deferoxamine, Deferasirox,
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Deferipone)
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, Lead poisoning - first line treatment? symptoms? --- blue "lead lines" at junction of teeth &
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gums, basophilic stippling of RBCs on peripheral blood smear - children in old houses
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eating paint chips or adults exposed to ammunition or batteries - Edetate calcium
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disodium (CaNa2 *EDTA*) (increases urinary excretion) -- weakness (microcytic
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hypochromic anemia), abdominal pain, constipation, neurotoxicity -- inhibition of
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ferrochelatase and d-aminolevulinic acid (ALA) dehydratase in heme synthesis pathway,
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instead incorporates zinc into protoporphyrin -- could also use dimercaprol, succimer,
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penicillamine
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Sarcoptes scabiei (mites & eggs) (Scabies) - presentation - Highly contagious, rapidly
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spreading, intensely pruritic rash (usually worse at night) - wrist, fingers, finger webs,
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palms
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Angiogenesis driven by what 2 factors: - VEGF - vascular endothelial growth factor
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FGF - fibroblast growth factor
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Leydig vs Sertoli cells - LH -> Leydig -> Testosterone
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FSH -> Sertoli -> (Inhibin B)
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GnRH
t(15;17) and Auer Rods (stain for myeloperoxidase) - Acute Promyelocytic Leukemia
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(APML) - fusion gene results in abnormal retinoic acid receptor, so treat with all-trans
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retinoic acid - also associated with DIC
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Potter Sequence - caused by renal anomaly (decreased urine output ->
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oligohydramnios): newborn with pulmonary hypoplasia, along with facial & lower limb
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deformities (compression) --- maternal use of ACEi/ARB can cause this, because
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Angiotensin II is required for normal renal development
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Carotid sinus massage, valsalva, and cold water immersion are _________ maneuvers.
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Can be used to terminate paroxysmal supraventricular tachycardia. - Vagal maneuvers -
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leads to increase in parasympathetic tone (bradycardia, hypotension, sometimes
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syncope) --- Carotid sinus afferent limb is glossopharyngeal nerve (CN IX), efferent limb is
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vagus (CN X).
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What nerve is vulnerable to injury in fibular neck fractures? What's the deficit? -
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Common peroneal (fibular) nerve -> causes weakness of foot dorsiflexion & eversion, and
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loss of sensation over dorsum of foot.
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Raphe nuclei in the CNS release what neurotransmitter? - Serotonin (target of SSRIs,
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SNRIs, TCAs, etc.)
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Metyrapone stimulation test causes a decrease in cortisol synthesis, and patients with an
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intact HPA axis will experience a reactive increase in _________. - ACTH (loss of
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negative feedback)
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