Uworld25

Question 1

What is indicative of secondary hyperaldosteronism?

Answer 1

Elevated serum aldosterone levels can manifest with hypertension, hypokalemia, and muscle weakness.

Increased levels of both renin and aldosterone are indicative of secondary hyperaldosteronism, which can be caused by renovascular disease and renin-secreting tumors.

Question 2

Fetal hyperinsulinemia causes what?

Answer 2

Neonates born to mothers with poorly controlled diabetes during pregnancy are exposed to high maternal glucose levels in utero, resulting in beta cell hyperplasia followed by excessive fetal insulin production.

Fetal hyperinsulinemia causes neonatal hypoglycemia, polycythemia, and macrosomia.

Question 3

What is sporotrichosis?

Answer 3

Sporotrichosis typically presents as papulonodular lesions distributed along the lymphatics and is histologically characterized by granulomatous and neutrophilic inflammation.

It is caused by the dimorphic fungus Sporothrix schenckii, which is often inoculated into the skin during outdoor activities such as gardening.

Question 4

Candida endophthalmitis typically occurs due to?

Answer 4

hematogenous dissemination to the choroid later in the setting of fungemia.

Most cases arise in hospitalized patients with indwelling central catheters. Patients usually have unilateral eye floaters and progressive vision loss.

Question 5

What is neuroleptic malignant syndrome?

Answer 5

an adverse reaction to antipsychotic medication characterized by severe “lead pipe” rigidity, hyperthermia, sympathetic hyperactivity, and mental status changes.

NMS is charactered by severe rigidity rather than the neuromuscular irritability (eg, hyperreflexia, myoclonus) seen in serotonin syndrome.

Question 6

Presentation and risk factors for renal cell carcinoma

Answer 6

Renal cell carcinoma may present with a combination of hematuria, abdominal mass, or flank pain; however, this triad occurs together in <10% of cases.

Pathology demonstrates rounded, polygonal cells with clear cytoplasm.

Risk factors: smoking, toxin exposure, and certain hereditary disorders (eg, von Hippel-Lindau syndrome)

Question 7

Which drugs are susceptible to chelation?

Answer 7

Tetracyclines interact with polyvalent cations (eg, iron, calcium, aluminum, magnesium) to form nonabsorbable chelate complexes in the GI tract.

This can lead to significantly decreased drug absorption and therapeutic effect.

Fluoroquinolones and thyroxine are also susceptible to chelation.

Question 8

What hormone inhibits lactation during pregnancy?

Answer 8

In pregnancy, progesterone is secreted by the corpus luteum and later by the placenta.

Although prolactin secretion increases as pregnancy progresses, high progesterone levels inhibit lactation by preventing binding of prolactin to receptors on alveolar cells in the breast.

Question 9

Which type of cancer can obstruct the eustachian tube?

Answer 9

The eustachian tube connects the middle ear to the nasopharynx. Cancer located in the nasopharynx can lead to obstruction of the eustachian tube, causing a middle ear effusion.

Question 10

What are the common adverse effects of nondihydropyridine calcium channel blockers (eg, diltiazem, verapamil)?

Answer 10

constipation, bradycardia, atrioventricular block (negative chronotropic effect), and worsening of heart failure in patients with left ventricular systolic dysfunction (negative inotropic effect)

Question 11

What is the most important prognostic determinant for colorectal cancer?

Answer 11

Tumor stage (degree of invasion/spread).

Tumors confined to the basement membrane and lamina propria are early stage and have the best prognosis.

Outcomes generally deteriorate as the stage advances: spread of tumor into the muscularis propria –> regional lymph nodes –> distant sites.

Question 12

What are risk factors for acne?

Answer 12

increased androgen levels, obstruction of pilosebaceous glands by oil based hair products, and mechanical irritation of skin follicles.

Sports participation frequently triggers acne due to the use to tight fitting clothing and protective gear.

Question 13

What are the labs seen in multiple myeloma?

Answer 13

Multiple myeloma is associated with increased bone resorption due to the production of tumor-related cytokines.

This results in elevated serum calcium levels, which reduce parathyroid hormone production.

Low PTH decreases renal calcium reabsorption (hypercalciuria) and in combination with renal insufficiency, reduces 1,25-dihydroxyvitamin D synthesis.

Question 14

What is methemoglobinemia?

Answer 14

causes dusky discoloration of the skin (similar to cyanosis), and because methemoglobin is unable to carry oxygen, a state of functional anemia is induced.

However, the blood partial pressure of oxygen will be unchanged as it is a measure of oxygen dissolved in plasma and is unrelated to hemoglobin function.

Question 15

The risk for UTI can be reduced by?

Answer 15

UTIs are common in hospitalized patients with indwelling urinary catheters.

The risk for UTI can be reduced by avoiding unnecessary catheterization, using sterile technique when inserting the catheter, and removing the catheter as soon as possible.

Question 16

Why is epinephrine often added to lidocaine?

Answer 16

Epinephrine is often added to lidocaine to produce vasoconstriction, which prolongs the duration of action of lidocaine, decreases bleeding during a procedure, and reduces systemic lidocaine absorption

Question 17

What is cord factor?

Answer 17

Mycobacterium tuberculosis grows in long, serpentine cords due to the presence of cord factor, a surface glycolipid, on the cell wall.

Cord factor is a primary virulence factor of M tuberculosis; it protects the bacteria from digestion by macrophages and also leads to the formation of caseating granulomas.

Question 18

What is SIADH- syndrome of inappropiate antidiuretic hormone secretion?

Answer 18

characterized by low plasma sodium and osmolality, inappropriately concentrated urine, and clinically normal volume status (euvolemic hyponatremia).

An important cause of SIADH is a paraneoplastic effect secondary to small cell carcinoma of the lung

Question 19

MOA of milrinone

Answer 19

phosphodiesterase-3 inhibitor that reduces the degradation of cyclic adenosine monophosphate to provide 2 beneficial effects for treating systolic heart failure.

Calcium influx into cardiomyocytes is increased, which increases cardiac contractility.

In addition, calcium-myosin light chain kinase interaction is reduced, which causes vasodilation and reduces cardiac preload and afterload

Question 20

What is familial hypercholesterolemia?

Answer 20

on of the most common AD disorders, is the result of heterozygous or homozygous LDL receptor gene mutations, which cause hepatocyte under expression of functional LDL receptors.

This condition can lead to accelerated atherosclerosis and early onset coronary artery disease

Question 21

What can improve carpal tunnel syndrome?

Answer 21

The carpal tunnel is formed by the carpal bones and the transverse carpal ligament (flexor retinaculum).

Carpal tunnel syndrome results from compression of the median nerve as it passes through the carpal tunnel with 9 flexor tendons.

Longitudinal incision of the transverse carpal ligament can decrease pressure within the carpal tunnel, improving patients’ symptoms.

Question 22

Why are women at high risk for UTIs?

Answer 22

Women are at high risk for urinary tract infections due to a shorter urethra that is close to the anus and vaginal introitus, which allows enteric pathogens to colonize the vagina and ascend to the bladder.

Acute simple cystitis is generally marked by dysuria, urinary frequency/urgency, suprapubic tenderness, and pyuria/bacteriuria on urinalysis.

Question 23

What happens during a fasting state with glucagon, epinephrine and cortisol?

Answer 23

In a fasting state, glucagon and epinephrine bind to transmembrane receptors and prevent hypoglycemia by increasing hepatic glycogenolysis and gluconeogenesis.

Prolonged fasting increases the secretion of cortisol, a steroid hormone that binds to an intracellular receptor and acts to increase transcription of enzymes involved in gluconeogenesis, lipolysis, and proteolysis.

Question 24

Cavernous hemangiomas carry an increased risk of?

Answer 24

Cavernous hemangiomas are vascular malformations that occur most commonly within the brain parenchyma; they carry an increased risk of intracerebral hemorrhage and seizure.

Question 25

What causes the fibrosis in a myocardial infarction?

Answer 25

After myocardial infarction, transforming growth factor-beta reduces inflammation and promotes tissue remodeling due to fibroblast proliferation and collagen deposition, resulting in fibrosis in the area damaged by ischemia. Abnormal myocardium at the scar border can predispose patients to sudden death as a result of arrhythmia.

Question 26

Citrate anticoagulants in high volume blood transfusion can chelate what?

Answer 26

Citrate anticoagulants in high volume blood transfusion can chelate plasma calcium, leading to hypocalcemia which causes peripheral neuromuscular excitability (eg, paresthesia, muscle spasms). This is most common with very rapid transfusion rates, but it can also be seen at lower rates in patients with hepatic insufficiency because citrate is metabolized by the liver

Question 27

Function of IL-10

Answer 27

Of the cytokines released in the setting of tissue injury, IL-10 plays important anti-inflammatory and immunomodulatory roles, especially in the pathogenesis of inflammatory bowel disease. IL-10 attenuates the immune response through the inhibition of Th1 cytokines, reduction of major histocompatibility complex class II expression, and suppression of activated macrophages and dendritic cells.

Question 28

What do homeobox genes encode for?

Answer 28

DNA-binding transcription factors that play an important role in the segmental organization of the embryo along the craniotomy-caudal axis.

Question 29

What is seen in diabetes insipidus following desmopressin adminstration during the water deprivation test?

Answer 29

Patients with diabetes insipidus are unable to concentrate their urine in response to dehydration. Following desmopressin administration during the water deprivation test, urine osmolality increases to normal levels in central DI but does not change in complete nephrogenic DI.

Question 30

Function of glucokinase

Answer 30

Insulin release by pancreatic beta cells is stimulated by increased glucose metabolism and ATP production. Glucokinase functions as a glucose sensor in pancreatic beta cells by controlling the rate of glucose entry into the glycolytic pathway. Mutations in the glucokinase gene lead to a state in which higher glucose levels are required to stimulate insulin secretion and are a cause of maturity-onset diabetes of the young.

Question 31

What is health promotion?

Answer 31

the process of enabling people to increase control over their health and its determinants and thereby improve their health

Question 32

What is intermittent explosive disorder?

Answer 32

characterized by recurrent episodes of explosive verbal or physical aggression. The aggressive behaviors are impulsive and grossly out of proportion to the provocation.

Question 33

What is the Ghon complex?

Answer 33

The Ghon complex describes the two initial sites (lower lobe of lung, ipsilateral hilar lymph node) of primary tuberculosis infection. Over time, these sites become calcified and fibrosed and can be visualized on gross pathology and radiographic imaging (Ranke complex)

Question 34

What is seen on EM and IF for membranous nephropathy?

Answer 34

Membranous nephropathy is a common cause of nephrotic syndrome in adults. EM of the glomerular capillary demonstrates irregular, subepithelial, electron-dense immune deposits on the glomerular basement membrane with moderate effacement of the podocyte food processes. Immunofluorescence microscopy demonstrates a diffuse granular pattern of IgG along the capillary loops

Question 35

What is Guillain-Barre syndrome?

Answer 35

Guillain Barre syndrome represents a group of immune-mediated polyneuropathies that are thought to be caused by molecular mimicry, leading to demyelination of the peripheral nerves. Up to 1/3 of GBS cases are preceded by a Campylobacter jejuni infection, which is a common cause of acute diarrheal illness.

Question 36

Chronic aortic regurgitation is caused by?

Answer 36

a reduction in diastolic blood pressure and a compensatory increase in left ventricular stroke volume. These changes create a high-amplitude, rapid fall pulsation (ie, widened pulse pressure) and the other characteristic findings of AR (head bobbing, "pistol shot" femoral pulses)

Question 37

What is costosternal syndrome (costochondritis)?

Answer 37

usually occurs after repetitive activity and is characterized by pain that is reproducible with palpation and worsened with movement or changes in position.

Question 38

What is congenital long QT syndrome?

Answer 38

Congenital long QT syndrome is most often caused by genetic mutations in a K+ channel protein that contributes to the outward-rectifying potassium current. A decrease in the outward K+ current leads to prolongation of action potential duration and QT interval. This prolongation predisposes to the development of life-threatening ventricular arrhythmias (eg, torsades de pointes) that can cause palpitations, syncope, seizures, or sudden cardiac death.

Question 39

Function of tetrahydrobiopterin and impaired synthesis causes?

Answer 39

Tetrahydrobiopterin (BH4) is an essential cofactor for hydroxylase enzymes involved in the metabolism of phenylalanine, tyrosine, and tryptophan. Impaired BH4 synthesis causes hyperphenylalaninemia and reduced levels of neurotransmitters (eg, dopamine, serotonin), causing progressive neurologic findings (developmental delay, seizures, microcephaly)

Question 40

What is a case control study?

Answer 40

observation study design; it begins with individuals who have the outcome (cases) and compares them with individuals who do not have the outcome (controls) according to history of exposure to >1 risk factors.

Question 41

What are the most common adverse effects of long-term lithium therapy?

Answer 41

Hypothyroidism and nephrogenic diabetes insipidus are the most common adverse effects of long term lithium therapy. Serum TSH and renal function (blood urea nitrogen and creatinine) should be monitored routinely

Question 42

Damage to the parietal association cortex leads to?

Answer 42

Because the parietal association cortex integrates multisensory information, damage can lead to difficulties in comprehension and problem-solving in the absence of motor or sensory deficits. Specific injury to the angular gyrus classically results in Gerstmann syndrome (agraphia, acalculia, finger agnosia, and left right disorientation)

Question 43

What is Ascaris lumbricoides?

Answer 43

Ascaris lumbricoides is transmitted via contaminated food or water. Eggs hatch into larvae in the small intestine, penetrate the intestinal wall, and migrate across the lung into the alveoli. Larvae are subsequently coughed up and swallowed into the gastrointestinal tract, where they mature to adult worms. Most patients are asymptomatic, but some develop early pulmonary manifestations (Loeffler syndrome) or later gastrointestinal symptoms.

Question 44

What are Pancoast tumors?

Answer 44

Tumors located in the lung apex (superior sulcus) are called Pancoast tumors. Invasion of surrounding structures can lead to ipsilateral Horner syndrome, rib destructuon, atrophy of hand muscles, and pain in the distribution of C8, T1, and T2 nerve roots.

Question 45

Androgen receptor dysfunction in patients with partial androgen insensitivity syndrome leads to?

Answer 45

decreased facial, axillary, and pubic hair; oligospermia, gynecomastia, and undervirilization of external genitalia (eg, microphallus). Loss of feedback inhibition of gonadotropin-releasing hormone results in elevated LH and testosterone levels.

Question 46

Function of cyclin-dependent kinases (CKDs) 4/6 and mutation

Answer 46

Cyclin-dependent kinases 4/6 regulate the movement of cells from G1--> S phase. Cancers often have mutations that enhance the activity or downstream effects of CDK 4/6, which contribute to unregulated cellular growth. Inhibitors to CDK 4/6 can be used to treat certain forms of cancer. However, they can inhibit cellular replication in other rapidly dividing cells such as the hematologic cells in the bone marrow (eg, neutropenia, anemia, or thrombocytopenia)

Question 47

What is atrial fibrillation?

Answer 47

Atrial fibrillation is recognized by an irregularly irregular rhythm with variable R-R intervals and absence of P waves of ECG. The development of AF most commonly involves ectopic electrical foci in the pulmonary veins that trigger fibrillary conduction in abnormal (remodeled) atrial tissue.

Question 48

What is the cumulative incidence of a disease?

Answer 48

the number of new cases of a disease over a specific period divided by the total population at risk at the beginning of the study (ie, the proportion of at-risk individuals who contract the disease over the specified period)

Question 49

Patients with multiple sclerosis most commonly develop urge incontinence due to?

Answer 49

loss of central nervous system inhibition of detrusor contraction in the bladder. As the disease progresses, the bladder can become atonic and dilated, leading to overflow incontinence.

Question 50

Treatment of malaria

Answer 50

Chloroquine is the treatment of choice for uncomplicated malaria in a chloroquine-sensitive geographic region. It eliminates susceptible erythrocytic forms of all Plasmodium species. Primaquine is added for Plasmodium viva and Plasmodium ovale infections to eradicate the intrahepatic stages (hypnozoites) of these malarial species, which are responsible for relapses.

Question 51

What is viridans streptococci associated with?

Answer 51

Viridans streptococci are normal inhabitants of the oral cavity and are a cause of transient bacteremia after dental procedures in healthy and diseased individuals. In patients with pre-existing valvular lesions, viridans streptocci can adhere to fibrin-platelet aggregates and establish infection that leads to endocarditis

Question 52

What structure can be injury during thyroid surgery?

Answer 52

The recurrent laryngeal nerve travels in close proximity to the inferior thyroid artery and can be injured during thyroid surgery, resulting in vocal cord paralysis (eg, hoarseness)

Question 53

Progressively weakening diaphragmatic contractions during maximal voluntary ventilation with intact phrenic nerve stimulation indicate?

Answer 53

neuromuscular junction pathology (eg, myasthenia gravis) or abnormally rapid primary muscle fatigue (eg, severe obstructive/restrictive lung disease)

Question 54

What is hirschsprung disease?

Answer 54

Hirschsprung disease is caused by abnormal migration of neural crest cells (ganglion cell precursors) during embryogenesis. Because neural crest cells migrate caudally down the bowel from the foregut, the rectum is always affected.

Question 55

What is measles?

Answer 55

Measles presents with fever, cough, rhinorrhea, and conjunctivitis followed by a maculopapular rash that starts on the face and spreads downwards. Koplik spots are pathognomonic for measles and characterized by tiny white or blue-gray lesions on the buccal mucosa.

Question 56

What can stress incontinence occur due to?

Answer 56

Stress incontinence, involuntary leakage of urine with increased intraabdominal pressure, can occur due to urethral sphincter dysfunction (eg, decreased sphincter tone). Risk factors include multiple prior vaginal deliveries, which can injure the external urethral sphincter or pudendal nerve.

Question 57

Loop diuretics MOA

Answer 57

Loop diuretics act by inhibiting the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, increasing Na, Cl, and H2O excretion. They are the most potent diuretics and are used as first-line therapy for rapid relief of symptoms in patients with acute decompensated heart failure.

Question 58

Stable angina pectoris results from?

Answer 58

myocardial oxygen demand-supply mismatch and manifests as chest pressure, tightness, or pain that is reliably produced by exertion and relieved by rest. It most commonly occurs due to a fixed atherosclerotic plaque obstructing >70% of the coronary artery lumen that limits blood flow during exertion.

Question 59

Dihydrofolate reductase and DNA polymerase are enzymes involved in?

Answer 59

DNA synthesis, which occurs during the S phase of cell cycle. The Rb protein, in its active (dephosphorylated) form, regulates cell cycle progression by preventing the transition from the G1 phase to the S phase. Phosphorylation of the Rb protein inactivates it, allowing cells to progress through the G1/S checkpoint and proliferate.

Question 60

Multiple myeloma is often treated with?

Answer 60

meds that block proteasome activity (eg, bortezomib) or increase ubiquitination of specific transcription factors (eg, lenalidomide). Lenalidomide increases E3 ubiquitin ligase binding to transcription factors overexpressed in myeloma, which results in increased transcription factor destruction by the proteosome and subsequent cancer cell death.

Question 61

Elderly patients have decreased saliva production due to?

Answer 61

acinar atrophy and fatty infiltration of the salivary glands. Other age-related changes include oral mucosal atrophy; weakening of the muscles of mastication, tongue muscles, and pharyngeal constrictors, and a decreased sense of taste and smell. As a result, elderly patients are at increased risk of dysphagia, malnutrition, and pneumonia.

Question 62

Extended-spectrum beta-lactamases can be produced by?

Answer 62

gram-negative bacteria, rendering cephalosporins and other beta-lactam antibiotics inactive. These genes can be transmitted between organisms through plasmid conjugation.

Question 63

What is seen with struvite stones?

Answer 63

Struvite stones are typically seen in patients with recurrent upper urinary infections by urease-producing organisms (eg, Proteus, Klebsiella). Hydrolysis of urea yields ammonia, which alkalinizes the urine and facilitates precipitation of magnesium ammonium phosphate. UA: hematuria and elevated urine pH

Question 64

What can be seen with patients ADPKD?

Answer 64

Intracranial berry aneurysms of the circle of Willis are often seen in patients with ADPKD; when ruptured, they cause subarachnoid hemorrhage that presents with sudden onset of "thunderclap headache"

Question 65

Bladder outlet obstruction leads?

Answer 65

leads to increased pressure proximally and finding of bladder distension and wall thickening, secondary vesicoureteral reflex, ureteral dilation, and hydronephrosis. The most common cause in newborn boys is posterior urethral valves due to a persistent urogenital membrane.

Question 66

Why is propylthiouracil preferred in pregnancy?

Answer 66

Thionamide antithyroid drugs (eg, propylthiouracil, methimazole) are used to decrease thyroid hormone production. Methimazole is preferred for most patients due to the hepatotoxicity of PTU. However, methimazole has potential teratogenic effects, so PTU is preferred in the first trimester of pregnancy.

Question 67

During the catabolism of proteins, amino groups are transferred to?

Answer 67

alpha-ketoglutarate to form glutamate. Alanine is the major amino acid responsible for transferring nitrogen to the liver for disposal. During the catabolism of proteins, amino groups are transferred to alpha-ketoglutarate to form glutamate. Glutamate is then processed in the liver to form urea, the primary disposal form of nitrogen in humans. Free ammonia is also excreted into the urine by the kidney for regulation of acid-base status.

Question 68

What is a crossover study?

Answer 68

In a crossover study, subjects are randomly allocated to a sequence of 2 or more treatments given consecutively. A washout (no treatment) period is often added between treatment intervals to limit the confounding effects of prior treatment.

Question 69

What are the hematologic abnormalities seen in lupus?

Answer 69

Systemic lupus erythematous is an autoimmune disorder that occurs most commonly in women. Hematologic abnormalities are common; autoantibodies against blood cell antigens (ie, type II hypersensitivity) can cause pancytopenia (ie, anemia, thrombocytopenia, leukopenia). In contrast, lupus nephritis is caused by immune complex deposition (ie, type III hypersensitivity) in the glomeruli.

Question 70

Injury to the prostatic plexus results in?

Answer 70

The prostatic plexus (inferior hypogastric nerves plus pelvic and sacral splanchnic nerves) lies within the fascia of the prostate and innervates the corpus cavernosa of the penis, which facilitates penile erection. As a result, prostatectomy or injury to the prostatic plexus can cause erectile dysfunction.

Question 71

How does a pulmonary embolism cause hypoxemia?

Answer 71

Pulmonary embolism is common in hospitalized and postoperative patients, and classically presents with sudden-onset shortness of breath and pleuritic chest pain. It causes hypoxemia due to ventilation/perfusion mismatch; arterial PCO2 is usually normal or decreased.

Question 72

What is the most common viral cause of aplastic crisis?

Answer 72

In patients with sickle cell anemia and other chronic hemolytic disorders, the most common viral cause of an aplastic crisis is infection of erythroid progenitor cells with parvovirus B19, a nonenveloped single-stranded DNA virus.

Question 73

What is Beck's triad in cardiac tamponade?

Answer 73

Cardiac tamponade typically presents with hypotension with pulsus paradoxus, elevated jugular venous pressure, and muffled heart sounds (Beck's triad). Pulsus paradoxus refers to an abnormal exaggerated decrease in systolic blood pressure >10 mmHg on inspiration, and is a common finding in patients with pericardial effusion with cardiac tamponade.

Question 74

What is focal nodular hyperplasia?

Answer 74

a benign liver lesion marked by a central stellate scar with radiating fibrous septa that microscopically contain abnormally large, thick-walled arteries. It usually arises in asymptomatic young women, and most cases are found incidentally.

Question 75

How is prostate cancer graded by?

Answer 75

Prostate cancer is graded by Gleason grade, which is a measure of glandular architecture disruption and risk of extra-organ spread; poorly differentiated prostate cancer (eg, no glandular structure) is assigned a high Gleason grade, whereas well-differentiated prostate cancer (eg, well formed glandular structure) is assigned a low Gleason grade. Staging is a marker of the extent of spread from the primary cancer site; regional lymph node involvement or distant metastases indicate a higher state of disease.

Question 76

What is seen in Cushing syndrome due to an ACTH-secreting pituitary adenoma (Cushing disease)?

Answer 76

ACTH is high and cortisol production can be suppressed by high dose, but not low dose, dexamethasone. In patients with ectopic ACTH production (eg, from malignant tumors), cortisol and ACTH production are not suppressed by low or high dose dexamethasone.

Question 77

Sustained-release drug preparations have reduced and delayed peak levels compared to immediate-release preparations due to?

Answer 77

slower absorption in the GI tract. Dampening of peak levels and prolonged absorption of the drug help maintain effective drug levels while minimizing toxicity.

Question 78

What is stress-induced (takotsubo) cardiomyopathy?

Answer 78

characterized by hypokinesis of the mid and apical segments and hyperkinesis of the basal segments of the left ventricle, resulting in systolic dysfunction. The condition is likely caused by a surge of catecholamines in the setting of physical or emotional stress. It usually affects postmenopausal women and resolves on its own within several weeks.

Question 79

What are the pressures in the heart?

Answer 79

Right-sided pressures in the heart are lower than left-sided pressures due to lower resistance in the pulmonary vasculature. Right ventricular diastolic pressure is similar to right atrial/central venous pressure (1-6 mmHg), whereas pulmonary artery diastolic pressure is slightly higher (6-12 mmHg) due to resistance to flow in the pulmonary circulation.

Question 80

Chronic opioid therapy can lead to?

Answer 80

tolerance (ie, increased amount of opioids to achieve the same pain relief), physical dependence (ie, development of withdrawal symptoms after abrupt cessation), and opioid use disorder (ie, uncontrolled use despite harmful effects).

Question 81

What is seen in CMV HIV associated esophagitis

Answer 81

linear ulcerations and intranuclear and cytoplasmic inclusions

Question 82

What is seen in HSV-1 HIV associated esophagitis?

Answer 82

small vesicles --> punched out ulcers and eosinophilic intranuclear inclusions (Cowdry type A) in multinuclear squamous cells at ulcer margins

Question 83

What is seen in Candida albicans HIV associated esophagitis?

Answer 83

Patches of adherent, gray/white pseudomembranes on erythematous mucosa Yeast cells and pseudohyphae invading mucosal cells

Question 84

Urinary tract obstruction causes?

Answer 84

Urinary tract obstruction causes reflux of urine into the renal tubules and increased tubular hydrostatic pressure. The intraglomerular capillary hydrostatic pressure is unchanged, resulting in a decreased hydrostatic pressure gradient across the glomerular capillary wall and a reduction in glomerular filtration. Oncotic pressure is maintained by large plasma proteins which are not filtered across the glomerular capillary basement membrane; it is unaffected by a urinary tract obstruction.

Question 85

What is papillary muscle rupture?

Answer 85

A life threatening complication that typically occurs 3-5 days after myocardial infarction and presents with acute mitral regurgitation and pulmonary edema. The posteromedial papillary muscle is supplied solely by the posterior descending artery, making it susceptible to ischemic rupture.

Question 86

Where is metaplasia often seen in?

Answer 86

Metaplasia is the substitution of one differentiated cell type for another in response to an adverse environmental stimulus. It is often seen in the bronchi of chronic cigarette smokers (ciliated columnar epithelium replaced by stratified squamous epithelium) and in the distal esophagus of patients with chronic gastroesophageal reflux (stratified squamous epithelium replaced by intestinal columnar epithelium).

Question 87

What is the number needed to harm?

Answer 87

number of people who must be exposed to a treatment to cause harm to 1 person who otherwise not have been harmed. To calculate NNH, the absolute risk increase between the treatment and control groups must be known: NNH = 1/ARI

Question 88

MOA of terbinafine

Answer 88

used for treatment of dermatophytosis. It inhibits synthesis of fungal membrane ergosterol by suppressing the enzyme squalene epoxidase.

Question 89

What is the H band?

Answer 89

the region of the sarcomere that contains only thick (myosin) filaments. The H band is the part of the A band (which is on either side of the M line) where thick filaments have no overlapping thin (actin) filaments.

Question 90

What are the adverse effects of methotrexate?

Answer 90

AE: stomatitis, bone marrow suppression, and liver function abnormalities. Methotrexate is the preferred disease modifying treatment for patients with moderate to severe rheumatoid arthritis.

Question 91

What is Chikungunya?

Answer 91

alphavirus transmitted by mosquitos in tropical and subtropical areas. Initial manifestations include fever, diffuse rash, and severe polyarthralgia (eg, wrist, fingers, ankles) or tenosynovitis.

Question 92

What is defective in I-cell disease?

Answer 92

posttranslational modification of proteins is important for targeting proteins to the correct location. This step is defective in I-cell disease, which is characterized by a lack of mannose residue phosphorylation, resulting in inappropriate trafficking of acid hydrolases to the extracellular space instead of to lysosomes.

Question 93

What is the Hawthorne effect (observer effect)?

Answer 93

the tendency of study subjects to change their behavior as a result of their awareness that they are being studied.

Question 94

What is chronic lymphedema?

Answer 94

most commonly caused by an acquired disruption of lymphatic drainage (eg, due to malignancy or lymphadenectomy), and typically presents with swelling and thickened skin in one or more extremities. Treatment is usually conservative and involves compression bandages and physiotherapy; diuretics are ineffective and contraindicated.

Question 95

CSF flows in what order?

Answer 95

lateral ventricles --> interventricular foramina of Monro --> third ventricle --> cerebral aqueduct of Slyvius --> fourth ventricle --> lateral foramina of Luschka or midline foramen of Magendie --> subarchnoid space.

Question 96

What is the cause of DiGeorge syndrome?

Answer 96

Chromosome 22q11.2 microdeletion results in DiGeorge syndrome (cardiac anomalies, hypoplastic or absent thymus and hypocalcemia) and velocardiofacial syndrome (cleft palate, cardiac anomalies, dysmorphic facies). Fluorescence in situ hybridization is the gold standard for detecting a microdeletion.

Question 97

MOA of ganciclovir

Answer 97

First line therapy for CMV colitis and retinitis. MOA: inhibits viral synthesis by blocking CMV DNA polymerase. Also blocks host DNA polymerase to a lesser degree, which can lead to hematologic side effects such as neutropenia, anemia, and thrombocytopenia.

Question 98

Glial fibrillary acidic protein (GFAP) stain

Answer 98

found in glia, and tumors of glial lineage are often positive for GFAP.

Question 99

Synaptophysin stain

Answer 99

normally found in neurons and neuroendocrine cells

Question 100

What is seen in esophageal squamous cell carcinoma?

Answer 100

presents mostly in the proximal 2/3 of the esophagus and frequently metastasizes to the mediastinal lymph nodes. Histo: sheets of atypical squamous cells with keratin pearls and intercellular bridges.

Question 101

What is seen in prerenal acute renal failure versus intrinsic?

Answer 101

Blood volume loss can cause prerenal or intrinsic acute renal failure. Prerenal ARF is associated with normal nephron function (eg, low urine sodium level, low fractionated sodium excretion, high urine osmolarity, and high BUN/creatinine ratio). Intrinsic ARF features diminished renal reabsorptive capacity (eg, lower urine osmolarity, higher urinary sodium, normal serum BUN/creatinine ratio).