Uworld35 Flashcards
What is the superficial inguinal ring
A physiologic opening in the external abdominal oblique aponeurosis, and surgical repair of an undescended testicle lodged in the inguinal canal involves moving the testis through the superficial inguinal ring and fixing it in the scrotum (ie, orchiopexy)
Paradoxical embolization, or passage of a thromboembolism from the venous to the arterial circulation, most commonly occurs through a?
patent foramen ovale.
A PFO is a one way tissue valve in the atrial septum that opens only when right exceeds left atrial pressure; venous return to the right atrium increases during the release (ie, relaxation) phase of the Valsalva maneuver and encourages the PFO to open
Estrogen or progesterone receptor positivity in breast cancer indicates?
Estrogen or progesterone receptor positivity in breast cancer indicates expected sensitivity to tamoxifen and aromatase inhibitor treatment.
HER2 overexpression in breast cancer suggests a more aggressive tumor that typically responds to therapy with the anti-HER2 monoclonal antibody trastuzumab
How does gemfibrozil (and other fibrates) cause gallstones?
Gemfibrozil (and other fibrates) can reduce cholesterol solubility and promote gallstone formation by reducing bile acid synthesis. Caution should be used when prescribing fibrate therapy to patients with underlying gallbladder disease.
What is diagnostic for cryptosporidium?
Cryptosporidium is fecal-orally transmitted protozoan that causes severe and protracted watery diarrhea in patients with impaired immunity (AIDS, immunosuppression). The presence of acid fast staining oocytes in a stool specimen is diagnostic.
Chi square is used for?
The chi-square test for independence is used to evaluate the association between 2 categorical variables
What is acute interstitial nephritis?
Fever, maculopapular rash, and acute renal failure occuring 1-3 weeks after beginning a new medication (antibiotics, proton pump inhibitors) is highly suggestive of acute interstitial nephritis.
Peripheral eosinophilia, sterile pyuria, eosinophiluria, and white blood cell casts may also be seen.
Histo: leukocyte infiltration and edema of the renal interstitium
Nonanion gap metabolic acidosis results from?
the loss of bicarbonate (HCO3) (usually from the kidneys or gastrointestinal tract), leading to a relative increase in H.
Common causes include renal tubular acidosis and severe diarrhea.
NAGMA is also referred to as hyperchloremic acidosis because the decrease in serum HCO3 is compensated for by an increase in serum chloride to maintain electronegative balance
What is trigeminal neuralgia?
caused by compression of the trigeminal nerve (CN V) root as it enters the pons, usually by an abnormal vessel loop. This leads to atrophy and demyelination of the nerve and causes short paroxysms of neuropathic pain
What causes renal infarctions?
Renal infarctions are most commonly caused by cardioembolic disease; atrial fibrillation is the greatest risk factor.
Clinical features include flank pain, nausea, vomiting, low grade fever, and hypertension (due to renin release of hypoxic tissue)
Gross path: sharply demarcated, yellow white, wedge shaped areas with surrounding hyperemia
What is entamoeba histolytica?
an amoeba that causes colitis characterized by trophozoites and flask shaped ulcers on biopsy. It can occasionally invade the colonic wall and disseminate through the blood to the liver, brain, or lungs. A single amebic liver abscess is the most common extraintestinal manifestation.
HIV infects what cells in the CNS?
HIV associated dementia has become rare since the advent of antiretroviral treatment but may still develop in patients with inadequately treated, late stage HIV infection.
In the CNS, HIV preferentially infects and replicates in macrophages
The musculocutaneous nerve innervates which muscles?
the coracobrachialis (flexes and adducts the arm) and the major elbow flexors (eg, biceps brachii, brachialis) and then continues distally to provide sensory innervation to the lateral forearm.
It is derived from the upper trunk of the brachial plexus (C5-C7) and can be injured by trauma or strenuous upper extremity exercise
What is a krukenberg tumor?
a gastric tumor that has metastasized to the ovary and can present with unintentional weight loss, epigastric pain, and adnexal masses.
Histo: large amounts of mucin with displaced nuclei, resulting in a signet ring appearance
Function of erythropoietin
EPO is produced primarily by peritubular fibroblast cells in the renal cortex in response to decreased renal oxygen delivery (decreased blood hemoglobin content).
EPO acts on erythrocyte precursor cells in the bone marrow to stimulate red blood cell production. Patients with chronic kidney disease have inflammatory damage to renal EPO-producing cells and often develop normocytic anemia due to insufficient EPO
What is the power of a test?
the probability of making the correct decision of rejecting a false H0 (ie, determining there is a correlation when one truly exists)
The p value is the probability of obtaining the observed result (or results more extreme) when H0 is assumed to be true; it is informally interpreted as the probability that the observed results are due to chance
What is hypertrophic cardiomyopathy?
characterized by asymmetric ventricular septal hypertrophy and dynamic left ventricular outflow tract obstruction.
Decreases in LV blood volume, via maneuvers or conditions that decrease preload (abrupt standing, valsalva strain) or afterload, worsen LVOT obstruction and increase the intensity of the HCM murmur
What is the pathogenesis of ankylosing spondylitis?
originates with defects in the intestinal mucosal barrier and exposure to the gut microbiome that lead to an enhanced IL-17 mediated inflammatory response. IL-17 stimulates production of additional inflammatory factors, primarily tumor necrosis factor-alpha and prostaglandins, which have synergistic proinflammatory effects and induce bony erosions and abnormal bone regrowth in the skeleton
MOA of 5-alpha reductase inhibitors (finasteride)
reduce conversion of testosterone to dohydrotestosterone. In men with benign prostatic hyperplasia, these agents reduce prostate volume and alleviate obstruction of urinary flow.
However, they are associated with androgen deficiency effects, including decreased libido, erectile dysfunction and decreased ejaculate volume
Temporomandibular joint disorder is associated with?
derangement of the temporomandibular joint and hypersensitivity of the mandibular nerve (CN V3)
Difference between right and left colon adenocarcinoma
Colon adenocarincoma is the most common gastrointestinal malignancy.
Right sided lesions are more likely to bleed and cause iron deficiency anemia; left sided lesions tend to present wtih obstructing symptoms (altered bowel habits, constipation, abdominal distension, nausea and vomiting)
What is normal pressure hydrocephalus?
presents with progressive gait difficulties, cognitive disturbances, and urinary incontinence. It is a form of communicating hydrocephalus characterized by ventriculomegaly without persistent elevations in intracranial pressure.
Brain imaging reveals ventricular enlargement out of proportion to sulci enlargement
What is vasospastic angina?
involves hyperactivity of coronary artery smooth muscle. Patients are usually young (age <50) and without significant risk factors for coronary artery disease; they experience recurrent episodes of chest discomfort that typically occur during rest or sleep and resolve within 15 minutes
What is the first line treatment for acute gouty arthritis?
Nonsteroidal anti-inflammatory drugs; they inhibit cyclooxygenase and therefore decrease prostaglandin synthesis and exert a broad anti-inflammatory effect that includes inhibition of neutrophils
What can lead to vascular dementia?
Small artery cerebral arteriolosclerosis can lead to ischemia that predominantly affects the subcortical areas. This can lead to vascular dementia associated with focal motor deficits, abnormal gait, urinary symptoms, and psychiatric symptoms
What is oculocutaneous albinism?
most commonly due to mutations that cause dysfunctional melanin synthesis within melanosomes. Patients typically have complete absence of melanin, resulting in white skin and hair, light irides, photophobia, and a propensity for sunburns
Priapism can be treated with?
The penile flaccid state is maintained by tonic alpha-adrenergic (norepinephrine) sympathetic activity, causing high vascular and trabecular smooth muscle tone, preventing corporal engorgement with blood.
Priapism can be treated with penile injections of an alpha-adrenergic agonist (phenylephrine), which induce smooth muscle contraction, leading to detumescence
What is a meningioma?
common adult intracranial tumors that typically arise in regions of dural reflection (falx cerebri, tentorium cerebelli).
Parasagittal lesions compressing the medial portion of the primary somatosensory cortex in the parietal lobe can result in contralateral lower limb sensory loss along the contralateral hemineglect if there is also damage to the parietal association cortex (non dominant hemisphere)
What is generally responsible for the value of the resting potential?
The resting membrane potential is the difference in the electrical charges across the cell membrane under steady-state conditions. The ions that are most permeable to the cell membrane make the largest contribution to the resting membrane potential.
In general, a high potassium efflux and some sodium influx are responsible for the value of the resting potential, which is typically about -70mV
What is a craniopharyngioma?
are suprasellar tumors found in children and composed of calcified cysts containing cholesterol crystals. They arise from remnants of Rathke’s pouch, an embryonic precursor of the anterior pituitary
What reduces the risk for neonatal tetanus?
Risk for neonatal tetanus is reduced by hygienic umbilical cord care and vaccination of the mother during pregnancy. Mothers who have been vaccinated provide passive immunity to the fetus via transplacental IgG, which protects the neonate until active immunization (vaccination) at approximately age 2 months
What is kaposi sarcoma
a vascular tumor strongly associated with human herpesvirus 8. It typically presents as red, purple, or brown papules and plaques on the extremities of patients who are HIV+
Gene mutations that render trypsin insensitive to cleavage inactivation cause?
hereditary pancreatitis.
Multiple inhibitory mechanisms exist to prevent premature activation of trypsinogen before it reaches the duodenal lumen, including cleavage inactivation of trypsin by trypsin itself and production of trypsin inhibitors (SPINK1)
Hereditary hemochromatosis can cause secondary hypogonadism due to?
deposition of iron in the pituitary gland, resulting in decreased gonadotropin secretion. Patients who develop secondary hypogonadism are also at risk for deficiencies in other pituitary hormones (central hypothyroidism)
Aminoglycosides are filtered across the glomerulus and concentrate in the renal tubules, leading to?
proximal tubular injury and acute tubular necrosis. This is visualized histologically as focal tubular epithelial necrosis, often with extensive granular casts that obstruct the tubular lumen and lead to rupture of the basement membrane
What is IgA nephropathy?
characterized as recurrent hematuria that occurs spontaneously or within a few days of upper respiratory or pharyngeal infection (synpharyngitic hematuria). Unlike other causes of immune complex mediated nephritic syndromes (poststrep glomerulonephritis), IgA nephropathy is associated with normal serum complement levels
Neuropathic foot ulcers can occur in diabetic patients when?
loss of pain sensation and proprioception delays recognition of injury due to trauma, friction, or sustained pressure (on plantar surface of foot bones). The risk is greatest in patients with longstanding diabetes who have poor glycemic control
What is osteoarthritis?
characterized by progressive fissuring and erosion of articular cartilage. Risk factors include advancing age, obesity, joint trauma, and repetitive stress.
Patients may have mild effusion and crepitus on PE, but signs of synovitis (redness, warmth) are less prominent than in the classic inflammatory arthritic disorders
What are the level of acetylcholine in Alzheimer?
Alzheimer disease is characterized by decreased levels of acetylcholine in the nucleus basalis of Meynery and the hippocampus, caused by diminished activity of choline acetyltransferase
Common side effects of HMG-CoA reductase inhibitors (statins)
muscle and liver toxicity. Hepatic transaminases should be checked prior to initiating therapy and repeated if symptoms of hepatic injury occur
