Uworld26 Flashcards
What is seen on physical examination of pneumothorax?
Pneumothorax is recognized on chest x-ray by a continuous line without lung markings peripheral to it.
Decreased tactile fremitus, decreased breath sound intensity, and hyperresonance to percussion are expected on physical examination.
Severe hypoxemia that does not correct with 100% supplemental oxygen is consistent with?
right to left shunt.
Intrapulmonary shunt effect occurs when an alveolar filling process (eg, diffuse pulmonary edema) causes poor alveolar ventilation despite continued perfusion; this improves with positive end-expiratory pressure.
What is vibrio vulnificus?
curve, gram-negative, free living bacterium that grows in marine environments.
Transmission primarily occurs due to the consumption of raw seafood (eg, oysters) or wound contamination.
Manifestations are often mild, but individuals with liver disease or iron overload are at very high risk of severe, fulminant infection (eg, sepsis, necrotizing fascitis)
What is Huntington disease?
AD, progressive neurodengerative disorder characterized by chorea, psychiatric symptoms, and dementia.
Psychiatric symptoms may occur early in the disease course and include irritability, anxiety, apathy, depression, and psychosis.
Adverse effects of amphotericin B
Amphotericin B is a polyene antifungal drug notorious for its renal toxicity.
Severe hypokalemia and hypomagnesemia are commonly seen during therapy and often require daily supplementation.
What is a delayed hemolytic transfusion reaction?
Delayed hemolytic transfusion reactions are usually mild, hemolytic reactions that occur >24 hours after blood transfusion.
They are a type of anamnestic response (delayed immunologic response) that occurs in patients previously exposed to a minor RBC antigen (eg, previous blood transfusion, pregnancy)
What is prepatellar bursitis?
A bursa is a fluid-filled synovial sac that serves to alleviate pressure from bony prominences and reduce friction between muscles and tendons.
Acute trauma or chronic repetitive pressure can cause injury, leading to localized pain and tenderness.
Prepatellar bursitis causes anterior knee pain and is usually due to repetitive or prolonged kneeling.
What is a chancroid due to Haemophilus ducreyi?
Chancroid, due to Haemophilus ducreyi, presents as deep, painful ulcers with ragged borders that are associated with a grey exudate and inguinal lymphadenopathy.
Diagnosis is established by gram stain and culture of the organism from a scraping of the ulcer base.
What is acute urinary retention?
characterized by anuria and bladder distension and can result in hydronephrosis and acute kidney injury.
A palpable, distended bladder is present on examination, and abdominal and flank pain may be present.
The most common cause of urinary retention is bladder outlet obstruction (urethral compression) due to benign prostatic hyperplasia.
Radiation-induced lung injury typically occurs following?
Radiation-induced lung injury typically occurs following thoracic irradiation (eg, breast cancer), which damages pneumocytes and vascular endothelial cells and initiates an inflammatory response (eg, IL-1, TNFa, TGF-b).
This immune response can have both acute (eg, exudative alveolitis, hyaline membrane formation) and delayed (eg, dense fibrosis) effects that typically manifest with cough and dyspnea.
Nonpitting edema often develops due to?
lymphatic outflow obstruction (eg, malignancy, congenital malformation).
Congenital lymphedema due to lymphatic network dysgenesis is common in Turner syndrome, which is characterized by webbed neck, horseshoe kidney, and nail dysplasia.
What is the locus coeruleus?
The locus coeruleus is a paired brainstem nucleus located in the posterior rostral pons near the lateral floor of the fourth ventricle and functions as the principal site for norepinephrine synthesis in the brain.
It projects to virtually all parts of the central nervous system and helps control mood, arousal (reticular activating system), sleep wake states, cognition, and autonomic function.
Staph epidermidis is a common cause of foreign body infections due to?
its ability to produce adherent biofilms.
What is MEN1?
Multiple endocrine neoplasia type 1 syndrome is characterized by tumors of the pituitary, parathyroid gland, and pancreas.
First generation H1 histamine receptor antagonists, including diphenhydramine and chlorpheniramine, can cause significant?
sedation especially when used with other meds that cause CNS depression (such as benzodiazepines)
What is epithelial ovarian cancer?
the most common ovarian malignancy.
Histo findings include anaplasia of epithelial cells with invasion into the stroma and multiple papillary formations with cellular atypia.
Epithelial ovarian tumors are associated with elevated cancer antigen 125, which can be used as a serum marker for this condition.
What is a Aschoff body?
Interstitial myocardial granulomas (Aschoff bodies) are found in carditis due to acute rheumatic fever, which develops after an untreated group A strep pharyngeal infection.
Aschoff bodies contain plump macrophages with abundant cytoplasm and central, slender ribbons of chromatin (Anitschkow, or caterpillar, cells)
What is frontotemporal dementia?
presents with early personality change, executive dysfunction, compulsivity, and hyperorality.
It is associated with neurofibrillary tangles due to abnormal tau proteins (also seen in Alzheimer dementia) and pathologically ubiquinated TDP-43 (also seen in amyotrophic lateral sclerosis)
What is Kallman syndrome?
In Kallman syndrome, there is an absence of GnRH secretory neurons in the hypothalamus due to defective migration from the olfactory placode.
These patients have central hypogonadism and anosmia, and often present with delayed puberty.
What is unique about Mycoplasma?
All organisms in the Mycoplasma genus, including Ureaplasma urealyticum, lack peptidoglycan cell walls and are therefore resistant to agents that target the cell wall such as penicillins, cephalosporins, carbapenems, and vancomycin.
Mycoplasma infections can be treated with antiribosomal agents (eg, tetracyclines, macrolides)
What is seen in diabetes with the polyol pathway?
In hyperglucemic states, aldose reductase converts glucose to sorbitol at a rate faster than sorbitol can be metabolized.
Sorbitol accumulates in certain cells such as lens cells, causing an influx of water and resulting in osmotic cellular injury.
Depletion of NADPH by aldose reductase also increases oxidative stress, which accelerates development of cataracts and diabetic microvascular complications (eg, neuropathy, retinopathy )
What is a manic episode?
Manic episodes are characterized by euphoric/irritable mood, impulsivity, hyperactivity, decreased need for sleep, pressured speech, racing thoughts, and grandiosity. They may occur with or without psychotic features.
MOA of aspirin
Aspirin is a nonsteroidal anti-inflammatory drug that primarily and irreversibly inhibits cyclooxygenase-1 (COX-1) when given in low doses.
Because irreversible COX-1 inhibition decreases platelet thromboxane A2 production for the duration of their lifespan (ie, 3-7 days), preoperative aspirin discontinuation is recommended at least 5 days prior to surgery to avoid excessive bleeding.
Activation of muscarinic receptors by acetylcholine or cholinergic agonists results in?
peripheral vasodilation due to synthesis of nitric oxide in endothelial cells, which leads to vascular smooth muscle relaxation (eg, hypotension).
Muscarinic receptor activation in other sites causes smooth muscle contraction.
What is prevalence?
the actual number of existing cases (old and new) of disease, either at a particular point in time (point prevalence), or during a period of time (period prevalence).
Estimates of disease prevalence in a population are affected by population dynamics.
Diffusion speed across a semipermeable membrane increases with?
higher molecular concentration gradients, larger membrane surface areas, and increased solubility of the diffusing substance.
Diffusion speed decreases with increased membrane thickness, smaller pore size, higher molecular weights, and lower temps.
How does mitochondrial dysfunction present?
presents with myopathy, nervous system dysfunction, lactic acidosis, and ragged red fibers on muscle biopsy.
Mitochondrial myopathies due to mtDNA mutations are inherited solely in a maternal fashion (ie, maternal inheritance).
Therefore, transmission occurs only through affected females and never through males.
Function of the iliohypogastric nerve
provides sensation to the suprapubic and gluteal regions and motor function to the anterolateral abdominal wall muscles.
Abdominal surgery (eg, appendectomy) can damage the nerve and cause decreased sensation and/or burning pain at the suprapubic region.
What are central scotomas?
A scotoma is a discrete visual field defect. Central scotomas are often caused by age-related macular degeneration that leads to the deposition of drusen clustered around the macula.
What is sensitivity?
represents the probability that an individual with disease with have a positive test result.
What is specificity?
represents the probability that an individual without disease will have a negative test result.
Drugs that have been shown to improve long term survival in patients with heart failure with reduced ejection fraction include?
beta blockers, ACE inhibitors, angiotensin II receptor blockers, angiotensin receptor-neprilysin inhibitors, and aldosterone antgaonists.
What causes rigor mortis?
Muscle contraction involves continuous actin-myosin cross-bridge cycling driven by release of sarcoplasmic calcium stores.
After death, loss of ATP prevents both myosin head detachment and clearance of cytoplasmic calcium, leading to diffuse and persistent skeletal muscle stiffening (rigor mortis)
How does cocaine effect the heart?
Cocaine intoxication causes increased sympathetic activity, which may be recognized by agitation, dilated pupils, tachycardia, and hypertension.
Cocaine-induced chest pain typically results from myocardial oxygen supply-demand mismatch (ie, myocardial ischemia) in the setting of coronary artery vasoconstriction.
Sublingual nitroglycerin and benzodiazepines help improve the myocardial ischemia and relieve the chest pain.
Opiate analgesics reduce pain by?
binding to mu receptors and inhibiting synaptic activity in the central nervous system.
Activation of presynaptic mu receptors on the primary afferent neuron leads to closure of voltage-gated calcium channels and reduced excitatory neurotransmitter release.
Binding to mu receptors on the postsynaptic membrane causes opening of potassium channels and membrane hyperpolarization.
What is the pathophysiology of benign neonatal hyperbilirubemia?
increased bilirubin production and decreased bilirubin conjugation as well as increased enterohepatic circulation.
Indirect hyperbilirubinemia and jaundice typically peak in the first few days of life and usually resolve without intervention.
What is neurofibromatosis type 1 (von Recklinghausen disease)?
AD disorder caused by mutations in the NF1 tumor suppressor gene.
Patients characteristically develop numerous cutaneous neurofibromas comprised mostly of Schwann cells, which are derived from the neural crest.
What is primary hyperaldosteronism?
involves excess aldosterone secretion, which causes hypertension and predisposes to hypokalemia and metabolic alkalosis; low plasma renin activity helps distinguish it from other causes of excess aldosterone (eg, renovascular disease).
First line-medical therapy: mineralocorticoid receptor antagonist (eg, spironolactone, eplerenone)
Foodborne botulism is caused by?
the ingestion of food contaminated with botulinum toxin, often from improperly home-canned foods.
It leads to eye and bulbar symptoms with symmetric descending muscle weakness; fever and mental status changes are typically absent.
What is first line pharmacotherapy for schizophernia?
Antipsychotic meds; MOA= D2 receptor antagonism
