Uworld20

Question 1

What is a femoral nerve block?

Answer 1

A femoral nerve block below the inguinal ligament (ie, in the inguinal crease) will anesthetize the skin and muscles of the anterior thigh, femur, and knee.

This type of block can be used in patients requiring tendon repair after a knee injury (eg, quadriceps rupture)

Question 2

Acute onset bloody diarrhea is most commonly due to?

Answer 2

E coli O157:H7, Shigella, or Campylobacter infection.

Shigella infection also classically causes high fever and left sided abdominal tenderness (due to rectosigmoid involvement) and often occurs in outbreaks (eg, day care center)

Question 3

How can head trauma cause anosmia?

Answer 3

Olfactory signals are relayed via the olfactory nerve (CN I) through the cribriform plate to the olfactory bulb, which then projects to the primary olfactory cortex in the medial temporal lobe.

Head trauma can tear olfactory nerve (CNI) rootlets as they cross the cribriform plate, causing anosmia. Anosmia is often interpreted by patients as loss of taste.

Question 4

What is a fibroadenoma?

Answer 4

Fibroadenomas are the most common benign tumor of the breast. They are characterized histologically by a myxoid stroma that encircles and sometimes compresses epithelium-lined glandular and cystic spaces

Question 5

The earliest morphologic change that occurs after a superficial thermal burn is?

Answer 5

erythema due to the release of preformed mediators (eg, histamine) from mast cells.

Deeper (eg, partial-thickness) burn wounds form blisters due to fluid extravasation through gaps between damaged venule endothelial cells

Question 6

What can happen to the respiratory system during a panic attack?

Answer 6

Panic attacks are typically accompanied by hyperventilation, leading to hypocapnia.

Cerebral blood flow is directly related to the arterial partial pressure of CO2; therefore, hypocapnia can lead to reduced cerebral blood flow and symptoms of cerebral hypoperfusion (eg, blurred vision, dizziness, lightheadedness)

Question 7

What is a S3?

Answer 7

S3 is a low frequency sound that occurs just after S2 and is typically associated with ventricular volume overload.

It is commonly heard in patients with mitral or aortic regurgitation or heart failure with reduced ejection fraction (eg, dilated cardiomyopathy)

Question 8

What are the physiologic adaptations in response to hypothermia?

Answer 8

The hypothalamus controls thermoregulation by promoting alterations in the autonomic nervous system and the adrenal and thyroid axes.

Physiologic adaptations in response to hypothermia include increased sympathetic activity and thyroid hormone release, shivering, and peripheral vasoconstriction. These actions normalize body temperature by reducing heat loss and increasing metabolic rate (promoting thermogenesis)

Question 9

What is Clostridium septicum?

Answer 9

a spore forming, exotoxin-producing, gram+ organism that is the most common cause of spontaneous gas gangrene (eg, rapid onset pain, hemorrhagic bullae, tissue crepitus). Underlying colonic malignancy is the greatest risk factor for infection

Question 10

MOA of ezetimibe

Answer 10

Ezetimibe reduces intestinal absorption of cholesterol. As a result, the amount of dietary cholesterol reaching the liver decreases. To compensate, the liver increases LDL receptor expression, which draws cholesterol out of the circulation

Question 11

What are the ocular manifestations in giant cell arteritis (temporal arteritis)?

Answer 11

Can lead to rapid, severe, and irreversible vision loss.

Involvement of the ciliary arteries in GCA leads to anterior ischemic optic neuropathy, which presents with a painless, rapidly progressive decrease in visual acuity.

Treatment includes systemic glucocorticoids (eg, prednisone, methylprednisolone)

Question 12

How is Neisseria meningitidis transmitted?

Answer 12

primarily by aerozolized droplets and subsequently colonizes the nasopharyngeal epithelium.

Penetration of the epithelium can lead to bloodstream infection.

Spread to the meninges occurs via transcellular penetration of the cerebral capillary endothelium or entry at the choroid plexus

Question 13

Lead inhibits what?

Answer 13

Young children who resides in homes built before 1978 are at significant risk for lead toxicity.

Lead directly inhibits ferrochelatase and aminolevulinic acid dehydrates, resulting in anemia, ALA accumulation, and elevated zinc protoporphyrin levels.

Neurotoxicity is also a significant long term complication

Question 14

The underlying biochemical feature of megalobastosis is?

Answer 14

defect in DNA synthesis. In patients with chronic alcohol use, megaloblastic macrocytic anemia can result from a nutritional deficiency of vit B12 or folate, which impairs synthesis of purine and pyrimidine bases

Question 15

Patients undergoing solid organ transplantation are at increased risk of gout due to?

Answer 15

meds that impair renal clearance of uric acid. Cyclosporine is particularly associated with gout in the post-transplantation period due to decreased uric acid excretion

Question 16

What is Reye syndrome?

Answer 16

acute liver failure (hepatomegaly, elevated aminotransferases, coagulopathy) and rapidly progressive encephalopathy related to hyperammonemia.

It usually develops in susceptible children during a viral infection after administration of salicylates (eg, aspirin), which can cause damage to the mitochondria and impair fatty acid beta oxidation within hepatocytes

Question 17

How does disseminated gonococcal infection present?

Answer 17

Neisseria gonorrhoeae is spread sexually by genitourinary secretions and can be prevented by the consistent use of condoms.

genitourinary infections are often asymptomatic, which increases the risk of spread through the bloodstream, leading to disseminated gonococcal infection.

Patients with disseminated disease typically present with the triad of polyarthralgia, tenosynovitis, and dermatitis or purulent arthritis.

Question 18

What is hairy cell leukemia?

Answer 18

an indolent B cell neoplasm predominantly found in middle aged men and characterized by bone marrow failure and infiltration into the reticuloendothelial system, causing massive splenomegaly.

Other typically features include a dry tap (unsuccessful bone marrow aspiration) and the presence of lymphocytes with cytoplasmic projections

Question 19

What is the p-value?

Answer 19

the probability of obtaining a result (ie, sample estimate) at least as large as the one observed when the population value claimed in the null hypothesis is assumed to be true.

A p-value <0.05 = statistically significant

Question 20

GERD is a common physiologic phenomenon in infants and is due to?

Answer 20

low tone of an immature lower esophageal sphincter. It is characterized by frequent spit up in an otherwise asymptomatic patient with appropriate weight gain

Question 21

What is a Councilman body?

Answer 21

Intravenous drug use is a risk factor for acute viral hepatitis, which is marked by panlobular inflammation, hepatocyte injury, and cell death.

To control the infection, cytotoxic T cell-mediated signals cause hepatocyte apoptosis, which is characterized by Councilman bodies ( round, intensely eosinophilic bodies)

Question 22

What is a Dupuytren contracture?

Answer 22

caused by progressive fibrosis of the superficial palmar fascia due to excessive fibroblast proliferation.

Pathognomonic fibrotic nodules and cords form along the flexor tendons, limiting extension of the affected digits.

Question 23

What is the most common cause of encephalitis outbreaks in the US?

Answer 23

Arboviruses, small RNA viruses transmitted by biting arthropods.

Because no vaccines are currently available, prevention primarily involves eliminating the vector arthropods (eg, infected mosquitos)

Question 24

What are the neutrophil chemotactic agents?

Answer 24

Leukotriene B4, C5a, IL-8, and 5-HETE (leukotriene precursor)

Question 25

Function of the rough endoplasmic reticulum?

Answer 25

covered with ribosomes and is involved in the transfer of proteins to the cell membrane and extracellular space. RER is well developed in protein secreting cells.

Question 26

Smooth endoplasmic reticulum function

Answer 26

lacks surface ribosomes and functions in lipid synthesis, carbohydrate metabolism, and detoxification of harmful substances

Question 27

What is retinal artery occlusion?

Answer 27

a cause of acute, painless, monocular vision loss. It is usually caused by thromboembolic complications of atherosclerosis traveling from the internal carotid artery and through the ophthalmic artery

Question 28

The majority of left ventricular myocardial perfusion occurs during?

Answer 28

The high systolic intraventricular pressure and wall stress of the left ventricle prevent myocardial perfusion during systole; therefore the majority of left ventricular myocardial perfusion occurs during diastole. Shorter duration of diastole is the major limiting factor for coronary blood supply to the left ventricular myocardium during periods of tachycardia (eg, exercise)

Question 29

What is Kaposi sarcoma?

Answer 29

a vascular neoplasm that often presents in HIV+ people, may involve the GI tract, causing bloody diarrhea, weight loss, and abdominal pain. Endoscopy: red-violet maculopapular lesions, raised hemorrhagic nodules, or polypoid masses. Histo: spindle shaped endothelial cells, slit like vascular spaces, and extravasated RBCs

Question 30

MI involving leads I and aVL means infarction involving which artery?

Answer 30

Leads I and aVL correspond to the lateral limb leads on ECG. Therefore, ST elevation or Q waves in these leads are indicative of infarction involving the lateral aspect of the left ventricle, which is supplied by the left circumflex artery

Question 31

What is sepsis?

Answer 31

Sepsis is a host inflammatory response to infection that can lead to multiple organ dysfunction due to defective mitochondrial oxidative respiration, resulting in a widespread dissociation between oxygen delivery and extraction. This manifests as elevated central venous oxygen saturation

Question 32

Prolonged beta blockade leads to?

Answer 32

When exposed to a prolonged environmental stimulus, cells can adjust their sensitivity to the stimulus by upregulating or downregulating surface membrane receptors. Prolonged beta blockade leads to upregulation of beta-adrenergic receptors and increased sensitivity to circulating catecholamines, causing an enhanced beta-adrenergic response on abrupt beta blocker cessation (ie, beta blocker withdrawal syndrome)

Question 33

What is medullary thyroid cancer?

Answer 33

a neuroendocrine tumor that arises from parafollicular calcitonin-secreting C cells. It is characterized by nests or sheets of polygonal or spindle-shaped cells with extracellular amyloid deposits derived from calcitonin

Question 34

What are the signs for renal cell carcinoma?

Answer 34

Classic signs and symptoms of renal cell carcinoma include hematuria, an abdominal mass, flank pain, and weight loss. Hypercalcemia and erythrocytosis are common paraneoplastic syndromes associated with RCC

Question 35

What causes cataracts at an early age?

Answer 35

Cataracts are related primarily to chronic photooxidative injury. Most patients with cataracts first develop symptoms at age >60 but exposure to systemic or ophthalmic glucocorticoids can cause cataracts at an early age. Other causes of premature cataract formation include diabetes mellitus, ocular trauma, and external radiation exposure

Question 36

Difference between first and second generation antipyschotics

Answer 36

Second generation are associated with a lower risk of extrapyramidal (acute dystonia, akathisia, parkinsonism) side effects compared with first generation antipsychotics but may cause adverse metabolic effects

Question 37

The most important determinant of intravenous infusion rate is?

Answer 37

the radius (diameter) of the intravenous catheter. For patients requiring a rapid blood transfusion, the shortest possible catheter with the widest possible diameter (eg, a large-bore peripheral intravenous catheter) should be selected

Question 38

What causes a lingual thyroid?

Answer 38

The thyroid gland is formed from evagination of the pharyngeal epithelium and descends to the lower neck. Due to failure of migration, the thyroid can reside anywhere along the thyroglossal duct's usual path, including the tongue (lingual thyroid)

Question 39

Traits for S saprophyticus

Answer 39

S saprophyticus is responsible for almost half of all UTIs in sexually active young women. Belongs to coagulase negative staphylococci and is unique because it is resistant to novobiocin

Question 40

Vitamin E deficiency is characterized by?

Answer 40

hemolytic anemia and neurologic deficits (eg, ataxia, loss of vibratory sensation, hyporeflexia). Fat-soluble vitamins (DEAK) require micelle formation for absorption, and risk factors for def include disorders affecting bile production (eg, primary biliary cholangitis)

Question 41

Which antiretroviral drugs do not require activation via intracellular phosphorylation?

Answer 41

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) like nevirapine and efavirenz

Question 42

What are acute phase reactants?

Answer 42

Acute phase reactants are proteins whose serum concentrations change by >25% during periods of inflammation. Procalcitonin is a unique APR that can rise or fall depending on the etiology of the infection; elevated levels correlate with a bacterial source, whereas low levels indicate a viral source.

Question 43

What are granulosa cell tumors?

Answer 43

ovarian sex cord stromal tumors that often secrete estrogen (eg, postmenopausal bleeding, endometrial hyperplasia) Gross path: large, unilateral, solid and cystic mass, which may appear yellow. Call-Exner bodies (ie, neoplastic granulosa cells forming follicle-like structures around central eosinophilic material) are often seen on microscopy

Question 44

During skeletal muscle contraction, calcium is released from the sarcoplasmic reticulum and binds?

Answer 44

binds troponin C, thereby allowing the binding of actin to myosin

Question 45

What is the lymphatic system in the lower extremities?

Answer 45

In the lower extremities, the superficial lymphatic system is divided into medial and lateral tracks. The medial track runs up to the superficial inguinal lymph nodes, bypassing the popliteal nodes. Consequently, lesions on the medial foot cause inguinal lymphadenopathy, whereas lateral lesions are more likely to cause lymphadenopathy in both the popliteal and inguinal areas

Question 46

What is a persistent vegetative state?

Answer 46

a chronic state of wakefulness without awareness, is a common post coma outcome following severe brain injury. Patients with PVS have sufficient brainstem function to maintain vital processes such as spontaneous respiration, but require continuos medical care due to absence of purposeful movement and communication

Question 47

Bupropion at high doses is associated with?

Answer 47

Bupropion is a first line antidepressant that is not associated with sexual side effects or weight gain. However, it is associated with an increased seizure risk at high doses and is contraindicated in patients with seizure disorders, anorexia nervosa, and bulimia

Question 48

What is Wolff-Parkinson-White syndrome?

Answer 48

An accessory atrioventricular conduction pathway causes ventricular preexcitation that manifests on ECG with a Wolff-Parkinson-White pattern, consisting of a shortened PR interval, slurred upslope of the QRS complex (delta wave) and a widened QRS interval. Some patients with an accessory conduction pathway develop paroxysmal tachyarrhythmias, most commonly atrioventricular reentrant tachycardia, which constitutes WPW syndrome.

Question 49

What is the long term treatment for specific phobia?

Answer 49

Exposure-based cognitive behavioral therapy, in which patients are systemically confronted with their feared objects or situations, is the most effective long term treatment for specific phobia

Question 50

What is oculocutaneous albinism?

Answer 50

AR disorder of melanin biosynthesis typically due to defective tyrosinase activity. Patients have reduced or absent melanin pigment in the skin, hair, and eye, as well as abnormal development of the fovea and optic nerve fibers, leading to reduced visual acuity and nystagmus

Question 51

What should you check prior to giving sodium-glucose cotransport-2 inhibitors (canagliflozin, dapaglifozin)?

Answer 51

Sodium-glucose cotransport-2 inhibitors (canagliflozin, dapaglifozin) lower glucose levels by decreasing renal reabsorption of glucose and have cardioprotective and renoprotective effects. Checking serum creatinine is recommended prior to initiation because the antihyperglycemic effect of these meds becomes less pronounced as renal function declines

Question 52

MOA of penicillamine

Answer 52

a first line treatment for Wilson disease, is a copper chelating agent that increases the urinary excretion of copper

Question 53

What is pneumocystic pneumonia?

Answer 53

an atypical fungal infection seen primarily in those with impaired cell-mediated immunity (eg, advanced AIDS). Manifestations often include slowly worsening pulmonary symptoms, hypoxia, and bilateral interstitial infiltrates on CXR. The cystic organism can be visualized using silver stain of respiratory secretions.

Question 54

Hypercalcemia in sarcoidosis is caused by?

Answer 54

parathyroid hormone independent formation of 1,25-dihydroxyvitamin D by activated macrophages, This leads to increased intestinal absorption of calcium

Question 55

What is ubiquitination?

Answer 55

Posttranslational modifications can alter protein abundance and activity despite unchanged levels of corresponding mRNA. Ubiquitination targets a protein for proteasomal destruction, lowering its half life, thereby lowering its abundance.

Question 56

Formula for relative risk

Answer 56

RR= [a/(a+b)] / [c/(c+d)] risk of an outcome in the exposed divided by the risk of that outcome in the unexposed

Question 57

What is pyruvate kinase deficiency?

Answer 57

Pyruvate kinase deficiency causes hemolytic anemia due to failure of glycolysis and resultant failure to generate sufficient ATP to maintain erythrocyte structure. In this case, splenic hyperplasia results from increased work on the splenic parenchyma, which must remove these deformed erythrocytes from the circulation

Question 58

What is incidence?

Answer 58

the number of new cases of a disease in a certain population at risk over a given time period

Question 59

What is prevalence?

Answer 59

total number of cases in the population over a given period

Question 60

What is seen in congenital syphillis?

Answer 60

Congenital syphilis should be suspected in a neonate with rhinorrhea and a desquamating, maculopapular rash involving the palms/soles, particularly in those with limited prenatal care. Nonspecific findings include fever, hepatosplenomegaly, lymphadenopathy

Question 61

What is coccidiodes immitis infection?

Answer 61

can be asymptomatic or it can cause pulmonary disease ranging from a flulike illness to chronic pneumonia. It causes disseminated disease in immunocompromised patients. Spherules containing endospores are found in tissue samples

Question 62

What is a paradoxical embolism?

Answer 62

Paradoxical embolism occurs when a thrombus from the venous system crosses into the arterial circulation via an abnormal connection between the right and left cardiac chambers (eg, patent foramen ovale, atrial septal defect, or ventricular septal defect). Atrial left-to-right shunts cause wide and fixed splitting of S2 and can facilitate paradoxical embolism due to periods of transient shunt reversal (eg, during straining or coughing)

Question 63

What increases the risk for Clostridiodes difficile?

Answer 63

C difficle commonly presents with watery diarrhea and abdominal pain; hospitalization and antibiotic use increase the risk of contracting the disease. A nucleic acid amplification test is the most sensitive method for diagnosis of C difficile infection in patients with clinical symptoms

Question 64

GTP is synthesized by what in the citric acid cycle?

Answer 64

GTP is synthesized by succinyl-CoA synthetase during the conversion of succinyl-CoA to succinate in the citric acid cycle. During gluconeogenesis, phosphoenolpyruvate carboxykinase uses GTP to synthesize phosphoenolpyruvate from oxaloacetate

Question 65

What is primary sclerosing cholangitis?

Answer 65

inflammation, fibrosis, and stricture of intrahepatic and extrahepatic bile ducts. Histo: fibrous obliteration of bile ducts and concentric periductal connective tissue deposition (eg, onion skin like patter). Manifestations reflect cholestasis and include jaundice, pruritus, fatigue, and a cholestatic injury pattern (ie, elevated alkaline phosphatase, direct hyperbilirubinemia)

Question 66

Which part of the nephron is impermeable to water regardless of serum vasopressin levels?

Answer 66

The ascendling limb of the loop of Henle. Reabsorption of electrolytes by the Na/K/2Cl cotransporter occurs in the thick ascending limb and contributes to formation of the corticomedullary concentration gradient.

Question 67

What is the blood supply to internal hemorrhoids?

Answer 67

Hemorrhoids result from abnormal distension of a portion of the anal arteriovenous plexus. The vascular components of internal hemorrhoids drain into the superior rectal vein, which subsequently drains into the inferior mesenteric vein. Band ligation of hemorrhoids cuts off their blood supply, causing them to degenerate

Question 68

Sporadic and hereditary (associated with von Hippel-Lindau disease) renal cell carcinomas are associated with mutations involving?

Answer 68

VHL gene on chromosome 3p. The VHL gene is a tumor suppressor that inhibits hypoxia-inducible factors; mutations lead to constitutive activation of these proteins, resulting in the activation of multiple angiogenic and tumorigenic growth factors (eg, VEG-F, PDG-F)

Question 69

How does the kidneys respond to chronic hypoxemia (detected by the transcription factor hypoxia-inducible factor 1-alpha)?

Answer 69

by substantially increasing production of erythropoietin. This hormone circulates to the bone marrow, where it accelerates the maturation of erythrocyte precursors, resulting in an elevated hematocrit (secondary polycythemia)

Question 70

Primary thrombotic microangiopathy syndromes result in?

Answer 70

Primary thrombotic microangiopathy syndromes share common clinical and pathologic features and result in platelet activation and diffuse microthrombosis in arterioles and capillaries. They present with hemolytic anemia, schistocytes, thrombocytopenia, and organ injury (eg, brain, kidneys)

Question 71

Mycobacterium avium complex infections are common in patients with advanced AIDS in which CD4 levels?

Answer 71

<50 The bacterium often spreads through the bloodstream and reticuloendothelial system and causes nonspecific symptoms (eg, fever, fatigue, weight loss, diarrhea), lymphadenopathy, and hepatosplengomegaly. Diagnosis is often made on blood culture or bone marrow aspirate (intracellular acid-fast bacteria that are not Mycobacterium tuberculosis)

Question 72

Patients with mature cystic teratomas are increased for of?

Answer 72

Mature cystic teratomas (ie, dermoid cysts) are derived from all 3 germ cell layers; therefore, the typical gross appearance is a multicystic mass containing yellow sebaceous fluid, solid components (eg, teeth, cartilage) and hair. Although often asymptomatic, affected patients are at increased risk of ovarian torsion.

Question 73

What is antisocial personality disorder?

Answer 73

involves a pattern of violating the rights of others, engaging in unlawful behaviors (eg, physical aggression, illegal occupations), and lacking remorse for transgressions. Individuals must be age >18 for diagnosis and have a history of conduct disorder prior to age 15.

Question 74

CN III palsy causes what?

Answer 74

Lesions involving the oculomotor nerve (CN III) cause ptosis, a downward and laterally deviated eye, impaired pupillary constriction and accommodation, and diagonal diplopia. The most dreaded cause of CN III palsy is an enlarging intracranial aneurysm

Question 75

Decreased erythrocyte transketolase activity is seen with deficiency of?

Answer 75

thiamine (vitamin B1), which is a cofactor for several enzymes (eg, pyruvate dehydrogenase) involved in glucose metabolism. Severe deficiency can lead to heart failure (wet beriberi), which in infants may manifest as respiratory distress and feeding intolerance with cardiomegaly and hepatomegaly.

Question 76

What is a regression analysis?

Answer 76

statistical technique used to describe the effect that 1 or more independent variables (eg, exposures, risk factors), which may be quantitative or qualitative, can have on 1 quantitative dependent variable (ie, outcome)

Question 77

What is a renal angiomyolipoma?

Answer 77

benign tumor composed of blood vessels, smooth muscle, and fat. Bilateral renal angiomyolipomas are associated with tuberous sclerosis, an AD condition.

Question 78

What is the translocation for Burkitt lymphoma?

Answer 78

Burkitt lymphoma is characterized by aggressive rapid growth and a starry sky microscopic appearance . Translocation between the c-Myc oncogene on the long arm of chromosome 8 with the Ig heavy chain region on chromosome 14 leads to overexpression of Myc, a nuclear phosphoprotein that functions as a transcription activator

Question 79

What is seen in chronic pancreatitis?

Answer 79

Chronic pancreatitis is an inflammatory disorder leading to pancreatic fibrosis and atrophy, resulting in endocrine (ie, insulin) and exocrine (eg, lipase, elastase, amylase, trypsin, chymotrypsin) insufficiencies. Patients typically have postprandial steatorrhea (ie, bulky diarrhea that is difficult to flush) and epigastric pain with meals. Low fecal elastase, positive Sudan staining, and elevated hemoglobin A1c support the diagnosis.

Question 80

Function of vasoactive intestinal peptide (VIP)

Answer 80

VIPomas are pancreatic islet cell tumors that hypersecrete vasoactive intestinal peptide (VIP), which increases intestinal chloride loss into the stool and causes excess losses of the accompanying water, sodium, and potassium. VIP also inhibits gastric acid secretion. Somatostatin inhibits the secretion of VIP and is used to treat the symptoms of VIPoma.

Question 81

What is acute compartment syndrome?

Answer 81

Acute compartment syndrome is caused by increased pressure within fascial compartments of the limbs, leading to impaired perfusion. ACS can cause severe pain, myonecrosis, and nerve injury. The anterior compartment of the leg, which contains the deep peroneal (fibular) nerve, is the most common site of ACS.

Question 82

What is ankylosing spondylitis?

Answer 82

characterized by stiffness and fusion of axial joints (ankylosis) and inflammation at the site of insertion of tendons into bone (enthesitis). Involvement of the thoracic spine and costovertebral and costosternal junctions can limit chest wall expansion, leading to hypoventilation

Question 83

What is intrinsic factor?

Answer 83

a glycoprotein that is normally secreted by parietal cells in the stomach that is necessary for the majority (99%) of vitamin B12 absorption in the ileum. Patients who have undergone a total gastrectomy require lifelong vitamin B12 supplementation due to inability to produce intrinsic factor

Question 84

What is an auer rod?

Answer 84

Auer rods (liner purple red inclusions within immature myeloid precursors) is helpful in making the diagnosis of acute myeloid leukemia

Question 85

What is a case control study?

Answer 85

observational study design; it begins with selecting individuals who have the outcome (cases) and individuals who do not have the outcome (controls) and then retrospectively comparing their history of exposure to risk factors

Question 86

What is Whipple disease?

Answer 86

caused by a chronic infection with Tropheryma whipplei, a gram+ bacterium that can affect multiple organ systems. It typically presents in middle aged men with malabsorption and arthralgia. Intestinal biopsy characteristically shows foamy macrophages in the lamina propria filled with bacilli that are positive for periodic acid-Schiff stain

Question 87

What is flumazenil?

Answer 87

Flumazenil is a benzodiazepine receptor antagonists. It can reverse the sedative effects of benzodiazepines related to overdose and procedural sedation

Question 88

What is anticholinergic toxicity?

Answer 88

characterized by fever, confusion, cutaneous flushing, dry oral mucosa, and dilated, poorly reactive pupils. Tricyclic antidepressants, particularly amitriptyline, have strong anticholinergic effects

Question 89

What can be used as abortive therapy for acute migraine?

Answer 89

The pathogenesis of migraines is complex and multifactorial but includes neurogenic inflammation, vasodilation, and sensitization of trigeminal afferents in the meninges. Triptans are serotonin 5-hydroxytrptamine 1B/1D agonists that stimulate the trigeminovascular serotonin receptors, resulting in inhibition of vasoactive peptide release, intracranial vasoconstriction, and decreased pain. They are used as abortive therapy for acute migraine.

Question 90

What is Meckel diverticulum?

Answer 90

a congenital outpouching of the intestine that commonly contains ectopic (heterotopic) gastric mucosa. Hydrochloric acid production by gastric epithelium can lead to intestinal ulceration and subsequent lower gastrointestinal bleeding and anemia

Question 91

What is lithium induced diabetes insipidus?

Answer 91

the result of lithium's antagonizing effect on the action of vasopressin on principal cells within the collecting duct system

Question 92

MOA of second generation antipsychotics?

Answer 92

block 5-HT2A receptors and have lower binding affinity at dopamine D2 receptor sites, which is associated with a lower risk of extrapyramidal side effects

Question 93

Patients with cystic fibrosis are at risk for pulmonary exacerbations due to?

Answer 93

Staph aureus, Pseudomonas aeruginosa, nontypeable Haemophilus influenza, and Burkholderia cepacia complex

Question 94

Left ventricular systole corresponds to?

Answer 94

the time of passive filling of the left atrium (atrial diastole). Mitral valve regurgitation leads to markedly elevated left atrial pressure during this period, creating the characteristic early and large V wave on left atrial pressure tracing

Question 95

Patients with IL-12 receptor deficiency are susceptible to severe mycobacterial infections due to?

Answer 95

the inability to mount a strong cell mediated granulomatous immune response; therefore, they require treatment with IFN-gamma. IL-12 stimulates the differentiation of naive Th0 into Th1 cells.

Question 96

What is dermatitis herpetiformis?

Answer 96

characterized by erythematous pruritic papules, vesicles, and bullae that appear symmetrically on extensor surfaces. It is strongly associated with celiac disease, a disorder characterized histologically by small intestinal intraepithelial lymphocytosis, crpyt hyperplasia, and villous atrophy

Question 97

MOA of physostigmine

Answer 97

cholinesterase inhibitor, increases acetylcholine levels by preventing its degradation by cholinesterase. Reverse anticholinergic toxicity

Question 98

Fetal lung maturity correlates with increased quantity and improved quality of surfactant production. Amniotic fluid markers of maturity during late gestation include?

Answer 98

increased phosphatidylcholine (lecithin) and phosphatidylglycerol and low sphingomyelin

Question 99

What can cause a misleadingly low hemoglobin A1c in relation to glycemic status?

Answer 99

Hemoglobin A1c is produced by nonenzymatic glycosylation of the hemoglobin molecule. A hemoglobin A1c assay provides an estimate of chronic glycemic control over the life span of circulating erythrocytes (3 months). However, rapid erythrocyte turnover (eg, hemolytic anemia) can give a misleadingly low hemoglobin A1c in relation to glycemic status