Uworld35

Question 1

What is the superficial inguinal ring

Answer 1

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)

Question 2

Paradoxical embolization, or passage of a thromboembolism from the venous to the arterial circulation, most commonly occurs through a?

Answer 2

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

Question 3

Estrogen or progesterone receptor positivity in breast cancer indicates?

Answer 3

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

Question 4

How does gemfibrozil (and other fibrates) cause gallstones?

Answer 4

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.

Question 5

What is diagnostic for cryptosporidium?

Answer 5

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.

Question 6

Chi square is used for?

Answer 6

The chi-square test for independence is used to evaluate the association between 2 categorical variables

Question 7

What is acute interstitial nephritis?

Answer 7

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

Question 8

Nonanion gap metabolic acidosis results from?

Answer 8

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

Question 9

What is trigeminal neuralgia?

Answer 9

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

Question 10

What causes renal infarctions?

Answer 10

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

Question 11

What is entamoeba histolytica?

Answer 11

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.

Question 12

HIV infects what cells in the CNS?

Answer 12

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

Question 13

The musculocutaneous nerve innervates which muscles?

Answer 13

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

Question 14

What is a krukenberg tumor?

Answer 14

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

Question 15

Function of erythropoietin

Answer 15

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

Question 16

What is the power of a test?

Answer 16

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

Question 17

What is hypertrophic cardiomyopathy?

Answer 17

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

Question 18

What is the pathogenesis of ankylosing spondylitis?

Answer 18

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

Question 19

MOA of 5-alpha reductase inhibitors (finasteride)

Answer 19

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

Question 20

Temporomandibular joint disorder is associated with?

Answer 20

derangement of the temporomandibular joint and hypersensitivity of the mandibular nerve (CN V3)

Question 21

Difference between right and left colon adenocarcinoma

Answer 21

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)

Question 22

What is normal pressure hydrocephalus?

Answer 22

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

Question 23

What is vasospastic angina?

Answer 23

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

Question 24

What is the first line treatment for acute gouty arthritis?

Answer 24

Nonsteroidal anti-inflammatory drugs; they inhibit cyclooxygenase and therefore decrease prostaglandin synthesis and exert a broad anti-inflammatory effect that includes inhibition of neutrophils

Question 25

What can lead to vascular dementia?

Answer 25

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

Question 26

What is oculocutaneous albinism?

Answer 26

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

Question 27

Priapism can be treated with?

Answer 27

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

Question 28

What is a meningioma?

Answer 28

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)

Question 29

What is generally responsible for the value of the resting potential?

Answer 29

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

Question 30

What is a craniopharyngioma?

Answer 30

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

Question 31

What reduces the risk for neonatal tetanus?

Answer 31

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

Question 32

What is kaposi sarcoma

Answer 32

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+

Question 33

Gene mutations that render trypsin insensitive to cleavage inactivation cause?

Answer 33

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)

Question 34

Hereditary hemochromatosis can cause secondary hypogonadism due to?

Answer 34

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)

Question 35

Aminoglycosides are filtered across the glomerulus and concentrate in the renal tubules, leading to?

Answer 35

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

Question 36

What is IgA nephropathy?

Answer 36

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

Question 37

Neuropathic foot ulcers can occur in diabetic patients when?

Answer 37

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

Question 38

What is osteoarthritis?

Answer 38

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

Question 39

What are the level of acetylcholine in Alzheimer?

Answer 39

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

Question 40

Common side effects of HMG-CoA reductase inhibitors (statins)

Answer 40

muscle and liver toxicity. Hepatic transaminases should be checked prior to initiating therapy and repeated if symptoms of hepatic injury occur

Question 41

What is anemia of chronic disease?

Answer 41

caused by chronic elevations in inflammatory cytokines, which lead to reduced iron absorption and increased iron retention in the reticuloendothelial system. This impairs iron availability and causes a normocytic or slightly microcytic anemia with low serum iron and low total iron-binding capacity.

Question 42

What is primary hyperparathyroidism?

Answer 42

characterized by oversecretion of parathyroid hormone despite normal (or elevated) serum calcium levels. Parathyroid hormone raises serum calcium and lowers serum phosphorus by increasing bone resorption (freeing calcium and phosphate), increasing renal reabsorption of calcium, and decreasing proximal tubular reabsorption of phosphate.

Question 43

What is Tay sachs disease?

Answer 43

AR disorder caused by beta-hexosaminidase A deficiency, which results in GM2 ganglioside accumulation in neuronal lysosomes. CF: progressive neurodegerenation (eg, development regression), an exarggerated startle reflex, and a cherry red macular spot

Question 44

What is a phase IV trial?

Answer 44

Phase IV (postmarketing) trials are conducted with drugs that have already been approved for use in order to study long-term effectiveness and better characterized uncommon or delayed adverse effects. They are typically designed to identify small treatment effects (ie, a high power study with large numbers of participants) in diverse patient populations, and the results may be used to refine the use of drugs in clinical practice.

Question 45

Immature T lymphocytes express what antigens?

Answer 45

Immature T lymphocytes express both the CD4 and CD8 cell surface antigens in addition to a complete TCR or a pro-TCR. These lymphocytes exist in the thymic cortex where they undergo positive selection and in the thymic medulla where they undergo negative selection.

Question 46

What is Crohn disease?

Answer 46

characterized by patchy, transmural inflammation of the GI tract. It can affect any part of the tract from the mouth to the anus. Complications include strictures (due to bowel wall edema, fibrosis, and thickening of the muscularis mucosae), fistulas (due to penetration of ulcers through the intestinal wall), and abscesses

Question 47

Epistaxis is commonly caused by?

Answer 47

irritation of the highly vascular mucosa at the anterior nasal septum. The anterior nasal septum contains the Kiesselbach plexus. The anterior ethmoidal, sphenopalatine, and superior labial arteries anastomose in this region

Question 48

Nitrites on dipstick are highly specific for?

Answer 48

urinary tract infections. False negative results can occur when the incubation time of nitrate reductase-producing bacteria in the bladder is insufficient (eg, frequent urination) to allow for accumulation of bacterial metabolites.

Question 49

What part of the brain has the greatest degree of atrophy in Alzheimer's?

Answer 49

The hippocampus is the area of the brain demonstrating the greatest degree of atrophy in Alzheimer's disease. Hippocampal atrophy on MRI is highly suggestive of the diagnosis.

Question 50

What is the V/Q mismatch in pulmonary embolism?

Answer 50

Ventilation-perfusion (V/Q) scans use radiotracers to compare the ventilation and blood perfusion of each area of the lung. V/Q mismatch with perfusion defects are often indicative of a pulmonary embolism, which are most commonly caused by deep vein thrombosis in the lower extremities that embolizes to the pulmonary vasculature

Question 51

What is a brief psychotic disorder?

Answer 51

characterized by >1 psychotic symptoms lasting >1 day and <1 month with full return to previous levels of functioning. Onset is typically sudden and associated with a stressor.

Question 52

What is a case control study?

Answer 52

used to compare the exposure status of people with the disease (cases) to the exposure status of people without the disease (controls). The main measure of association is the odds ratio.

Question 53

What is beta-endorphin?

Answer 53

Beta-endorphin is one endogenous opioid peptide that is derived from proopiomelanocortin (POMC). POMC is a polypeptide precursor that goes through enzymatic cleavage and modification to produce not only beta-endorphins, but also ACTH and MSH. The fact that beta-endorphin and ACTH are derived from the same precursor suggests that there may be a close physiological relationship between the stress axis and the opioid system.

Question 54

In placement of a suprapubic cystostomy, the trocar and cannula will pierce?

Answer 54

The bladder is extraperitoneal. In placement of a suprapubic cystostomy, the trocar and cannula will pierce the layers of the abdominal wall but will not enter the peritoneum.

Question 55

What is hidradenitis suppurative?

Answer 55

results from the occlusion of folliculopilosebaceous units. Subsequent follicular rupture and inflammation form painful nodules and abscesses, which may progress to sinus tracts, scars, and comedones with chronic, recurrent disease.

Question 56

What is neurocysticercosis?

Answer 56

a helminth infection that occurs after the ingestion of Taenia solium eggs. It often presents with adult-onset seizure in patients from an endemic area. Imaging reveals >1 cystic brain lesions. The presence of a scolex, the anterior portion of the worm with hooks and suckers is diagnostic.

Question 57

What is Gilbert syndrome?

Answer 57

characterized by indirect hyperbilirubinemia due to decreased bilirubin conjugation. Patients have recurrent, self resolving episodes of scleral icterus and jaundice triggered by stress.

Question 58

What characteristics of a drug results in a low Vd?

Answer 58

Characteristics of a drug such as high molecular weight, high plasma protein binding, high charge, and hydrophilicity tend to trap the drug in the plasma compartment resulting in a low Vd (3-5 L)

Question 59

What is primary biliary cholangitis?

Answer 59

a chronic liver disease characterized by autoimmune destruction of the intrahepatic bile ducts and cholestasis (elevated alkaline phosphatase). The condition is most common in middle aged women with severe pruritis (especially at night) often one of the first reported symptoms.

Question 60

Fracture of the posterior vertebral arch often occurs at?

Answer 60

the pars interarticularis (ie, spondylolysis). Bilateral disruption of the pars interarticularis can lead to anterior displacement of the vertebral body (ie, spondylolisthesis)

Question 61

What is Q fever?

Answer 61

a zoonotic infection that occurs in farm workers exposed to waste from cattle and sheep. Its causative agent is Coxiella burnetii. A patient with exposure to waste from farm animals who develops a nonspecific illness (myalgias, fatigue, fever (>10 days), retroorbital headache) with a normal leukocyte count, thrombocytopenia and increased liver enzymes should be evaluated for acute Q fever infection.

Question 62

What is a ventricular septal defect?

Answer 62

A ventricular septal defect, classically characterized by a harsh, holosystolic murmur at the left lower sternal border, causes a left to right shunting of oxygenated blood from the left ventricle to the right ventricle. Therefore, right ventricular oxygen saturation is increased compared to normal.

Question 63

Where does iron absorption occur?

Answer 63

Iron absorption occurs predominantly in the duodenum and proximal jejunum. Bypass of this segment of small bowel by gastrojejunostomy results in iron deficiency anemia that can be corrected with pharmacologic iron supplementation. Malabsorption of thiamine, folate, vitamin B12, fat soluble vitamins (esp vitamin D), and calcium is also common following gastric bypass procedures.

Question 64

What is seen in a ruptured abdominal aortic aneurysm?

Answer 64

a surgical emergency that usually presents with the acute onset of severe abdominal and back pain in patients with appropriate risk factors (eg, advanced age, smoking, atherosclerosis). Accompanying syncope, hypotension, and shock may occur quickly (intraperitoneal rupture) or may be delayed (retroperitoneal rupture)

Question 65

What is serotonin syndrome?

Answer 65

Coadministration of tramadol with serotonergic medications such as selective serotonin reuptake inhibitors increases the risk of serotonin syndrome, which presents with the characteristic triad of mental status changes (agitation, confusion), autonomic instability (hyperthermia, diaphoresis) and neuromuscular hyperactivity (tremor, myoclonus)

Question 66

How is prostate cancer treated?

Answer 66

Because prostate cancer is an androgen-dependent tumor, patients with advanced disease are generally treated with surgical or medical orchiectomy. Medical orchiectomy uses GnRH analogues to reduce LH production, which subsequently reduces androgen production in the testes. Because there is an initial surge in androgens at the start of therapy (due to stimulation of the GnRH receptor), patients prescribed GnRH therapy are usually treated with a few weeks of androgen-receptor inhibitors (eg, bicalutamide)

Question 67

Pathogenesis of tertiary syphilis?

Answer 67

Tertiary syphilis can result in thoracic aortic aneurysm. If the aneurysm compresses adjacent structures and dilates the aortic valve ring, a murmur and mediastinal widening might be present. The pathogenesis begins with vasa vasorum endarteritis and obliteration, resulting in inflammation, ischemia, and weakening of the aortic adventitia. Fluorescent treponemal antibody absorption testing is specific for syphilis.

Question 68

Erythropoiesis-stimulating agents (erythropoietin, darbepoetin alpha) are associated with increased risk for?

Answer 68

Erythropoiesis-stimulating agents (erythropoietin, darbepoetin alpha) can substantially improve anemia symptoms, avoiding the need for blood transfusions in chronic kidney disease and dialysis patients. However, ESAs are associate with increased risk for hypertension and thromboembolic events

Question 69

What are seborrheic keratoses?

Answer 69

pigmented macules or plaques with a greasy surface and well demarcated borders. Rapid onset of numerous lesions is an indicator of internal malignancy (Leser-Trelat sign), especially gastric adenocarcinoma.

Question 70

Mitochondrial vacuolization is typically a sign of?

Answer 70

irreversible cell injury, signifying that the involved mitochondria are permanently unable to generate ATP

Question 71

What is the pathogenesis of acute appendicitis?

Answer 71

Obstruction of the appendiceal lumen (eg, fecalith, lymphoid hyperplasia) is frequently the inciting event in the pathogenesis of acute appendicitis, which typically presents with periumbilical pain that shifts to the right lower quadrant. Gross pathologic examination often shows an edematous, erythematous appendix with purulent exudate

Question 72

What is a Kayser-Fleischer ring?

Answer 72

an ophthalmologic finding most strongly associated with Wilson's disease. It is seen most frequently in patients with neuropsychiatric complications. Basal ganglia atrophy is typically present in these patients.

Question 73

What are xanthomas?

Answer 73

Xanthomas are suggestive of hyperlipidemia, especially when present in conjunction with a family history of early cardiac death.

Question 74

What is Guillain-Barre syndrome?

Answer 74

an acute demyelinating polyneuropathy. It is thought to be dye to molecular mimicry and is commonly preceded by an upper respiratory viral illness or gastroenteritis. Segmental demyelination of the peripheral nerves and an endoneural inflammatory infiltrate are seen on light microscopy.

Question 75

Physical exam findings in constrictive pericarditis?

Answer 75

In constrictive pericarditis, normal pericardium is replaced by dense, rigid pericardial tissue that restricts ventricular filling, leading to low cardiac output and progressive right sided heart failure. PE: elevated jugular venous pressure, pericardial knock, pulsus paradoxus, and a paradoxical rise in JVP with inspiration (Kussmaul sign)

Question 76

What is eccentric ventricular hypertrophy?

Answer 76

results in a dilated cavity with relatively thin ventricular walls due to the addition of myocardial contractile fibers in series in response to chronic volume overload. Chronic aortic regurgitation can result from aortic root dilation and is a common cause of eccentric hypertrophy

Question 77

What is the nucleotide excision repair of UV damaged DNA?

Answer 77

Pyrimidine dimers are formed in DNA as a result of ultraviolet light exposure. They are recognized by a specific endonuclease complex that initiates the process of repair by nicking the damaged strand on both sides of the pyrimidine dimer. The damaged segments is then excised, and replacement DNA is synthesized by DNA polymerase.

Question 78

Acute hepatitis B infection can cause?

Answer 78

a serum sickness-like syndrome with joint pain, lymphadenopathy, and a pruritic urticarial rash. Other features may include right upper quadrant pain, hepatomegaly, and elevated hepatic transaminase levels.

Question 79

What is Marfan syndrome?

Answer 79

a connective tissue disorder in which defective fibrillin-1 decreases tissue integrity and increases expression of transforming growth factor-beta. Cardiac effects include myxomatous degeneration and prolapse of the mitral valve with associated regurgitation, which manifests as a midsystolic click and mid-to-late systolic murmur

Question 80

Monoamine oxidase inhibitors are particularly useful in patients with?

Answer 80

treatment resistant major depressive disorder with atypical features. Increased appetite and sleep, leaden paralysis, rejection sensitivity, and mood reactivity are hallmarks of the atypical subtype.

Question 81

What is fragile X syndrome?

Answer 81

caused by increased CGG trinucleotide repeats within the fragile X messenger ribonucleoprotein 1 (FMR1) gene on the long arm of the X chromosome. This leads to hypermethylation and silencing of FMR1.

Question 82

What is sarcoidosis?

Answer 82

characterized by noncaseating granulomas. Multinucleated giant cells, formed by macrophage fusion, are frequently seen. Sarcoidosis commonly involves the lungs with interstitial or nodular infiltrates; extrapulmonary manifestations can affect lymph nodes, eyes (uveitis), skin, internal organs, and salivary glands.

Question 83

What happens in the phosphatidylinositol 2nd messenger system?

Answer 83

After a ligand binds to a G-protein coupled receptor that activates phospholipase C, membrane phospholipids are broken down into diacylglycerol (DAG) and inositol triphosphate (IP3). Protein kinase C is subsequently activated by DAG and calcium; the latter is released from the endoplasmic reticulum under the influence of IP3.

Question 84

What is alpha-fetoprotein?

Answer 84

a serum tumor marker that is often moderately elevated in patients with chronic viral hepatitis. However, it can be strikingly elevated in those with hepatocellular carcinoma, and a sudden rise can be a sign that a patient with chronic liver disease is harboring hepatocellular carcinoma.

Question 85

Voltage gated sodium channels are important for?

Answer 85

the generation and propagation of action potentials. When the action potential reaches the axon terminal, voltage gated calcium channels open and allow the influx of calcium, which is essential for the fusion and release of neurotransmitter vesicles into the synaptic cleft.

Question 86

Why does hep b and hep C increase the risk for hepatocellular carcinoma?

Answer 86

Both hep B and hep C infections increase the risk of hepatocellular carcinoma due to chronic hepatic inflammation and cell turnover. HBV is also carcinogenic due to the production of oncogenic proteins and the insertion of the HBV genome into host chromosomes.

Question 87

What is morbilliform drug eruption?

Answer 87

a type IV HSR caused by drugs (anticonvulsants, antibiotics) or their metabolites that typically occurs 5-21 days following drug initiation. Lesions consist of erythematous macules and papules, distributed symmetrically on the trunk and extremities, sometimes accompanied by low grade fever. Mucosal involvement is absent.

Question 88

The lungs are supplied by?

Answer 88

The lungs are supplied by dual circulation from both the pulmonary and bronchial arteries. This collateral circulation can help protect against lung infarction due to pulmonary artery occlusion (ie, pulmonary embolism), as the bronchial circulation can continue to provide blood to the lung parenchyma.

Question 89

What is the V/Q for a pulmonary embolism?

Answer 89

Ventilation/perfusion scanning can be useful for diagnosing pulmonary embolism. A large perfusion defect without ventilation defect is the characteristic positive test result.

Question 90

What is poststreptococcal glomerulonephritis?

Answer 90

Poststreptococcal glomerulonephritis is a potential complication of group A streptococcal infection (eg, impetigo, pharyngitis). Symptoms include proteinuria (often associated with periorbital or generalized edema) and hematuria. Inmost regions of the world, acute rheumatic fever is a post infectious sequela of streptococcal pharyngitis only, not impetigo.

Question 91

What is intestinal-type gastric adenocarcinoma?

Answer 91

Intestinal type gastric adenocarcinoma is visualized endosopically as an ulcerated mass with irregular folded or heaped up edges. Histologically, it resembles colon adenocarcinoma and is characterized by glandular structures containing intestinal like columnar (or cuboidal) cells. RF: helicobacter pylori infection, a high salt diet, n-nitroso-containing compounds, and autoimmune atrophic gastritis

Question 92

What is a randomized control trial?

Answer 92

an experiment in which participants are randomly allocated to >2 groups to assess the effect of specific interventions (eg, treatments)

Question 93

What does seborrheic keratosis look on microscope?

Answer 93

Seborrheic keratosis is a common epidermal tumor that presents as a tan or brown, round lesion with a well demarcated border and "stuck on" appearance. Microscope: small cells resembling basal cells, with pigmentation, hyperkeratosis, and keratin-containing cysts. Rapid onset of numerous lesions is often associated with internal malignancy (Leser Trelat sign)

Question 94

What is seen in an infraspinatus injury?

Answer 94

The rotator cuff muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) all insert onto the humeral head, allowing them to stabilize the shoulder joint and move the arm at the shoulder. An infraspinatus injury would result in shoulder pain and weak, painful external rotation of the arm against resistance.

Question 95

What is aseptic meningitis?

Answer 95

Fever, meningeal signs (headache, neck stiffness) and cerebrospinal fluid that shows lymphocytic pleocytosis, a modestly elevated protein level (<150 mg/dL), and normal glucose are suggestive of aseptic meningitis. Enteroviruses are the most common cause of aseptic meningitis.

Question 96

Which diabetic meds increase endogenous insulin secretion?

Answer 96

Proinsulin is cleaved into insulin and C peptide; therefore, C peptide is a marker of endogenous insulin secretion. Diabetic medications that increase endogenous insulin secretion (eg, sulfonylureas (glyburide) elevate the C-peptide level.

Question 97

Treatment of acute arsenic poisoning?

Answer 97

ACute arsenic poisoning impairs cellular respiration and presents with abdominal pain, vomitting, diarrhea, hypotension and a garlic odor on the breath. Insecticides and contaminated water are common sources of arsenic. Dimercaprol is the chelating agent of choice

Question 98

What would case a steep decline in the worldwide incidence of hepatocellular carcinoma?

Answer 98

Universal vaccination of children against HBV

Question 99

Pain arising from the mediastinal or diaphragmatic pleura will be carried by?

Answer 99

Irritation of the parietal pleura will cause sharp pain, which is worse on inspiration. Pain arising from the mediastinal or diaphragmatic pleura will be carried by the phrenic nerve and referred to the C3-C5 distribution.

Question 100

What is herpes zoster ophtalmicus?

Answer 100

caused by reactivation of varicella-zoster virus in the ophthalmic division of the trigeminal nerve (CN V1). It is characterized by a painful, dermatomal rash and ocular involvement (acute keratitis, corneal ulceration). It most commonly occurs in elderly and immunosuppressed patients