Uworld34

Question 1

What is the haldane and Bohr effect?

Answer 1

The binding of O2 to hemoglobin increases the affinity for binding of subsequent O2 molecules (cooperative binding). In the lungs, the binding of O2 to hemoglobin drives the release of H+ and CO2 from hemoglobin (Haldane effect).

In the peripheral tissues, high concentrations of CO2 and H+ facilitate O2 unloading from hemoglobin (Bohr effect)

Question 2

Risk factors for aortic dissection versus aortic aneurysms

Answer 2

Hypertension is the single most important risk factor for the development of intimal tears leading to aortic dissection.

Hypertension, smoking, diabetes mellitus, and hypercholesterolemia are all major risk factors for atherosclerosis, which predisposes more to aortic aneurysm formation than aortic dissection.

Question 3

MOA of amiodarone

Answer 3

Amiodarone primarily functions as a class III antiarrhythmic, inhibiting the delayed rectifier potassium current to slow ventricular repolarization and prolong the QT interval.

It also inhibits fast sodium channels (class I effect) to slow ventricular depolarization and prolong QRS complex duration.

Beta blockade (class II effect) and inhibition of slow L-type calcium channels (class IV effect) slow conduction in the sinus node and atrioventricular node causing decreased sinus rate and a prolonged PR interval

Question 4

What is the clinical presentation of tertiary syphilis?

Answer 4

cardiovascular involvement and gummas.

Gummas are necrotizing granulomas occuring on the skin, mucosa, subcutaneous tissue, and bones and within other organs. Neurosyphilis can occur at any stage of infection.

Question 5

What is observer bias?

Answer 5

occurs when the investigator’s evaluation is affected by preconceived expectations or prior knowledge, typically leading to overestimation of the disease association or treatment effects. This type of bias can be reduced by conducting a blinded study in which observers are unaware of study details and patient characteristics that could unduly influence them.

Question 6

Chronic adminstration of GnRH agonists (leuprolide) suppresses?

Answer 6

pituitary LH release and leads to reduced production of testosterone.

Lower levels of circulating testosterone produce a clinical effect similar to that of surgical orchiectomy and can lead to accelerated bone loss and increased risk for osteoporosis

Question 7

Restrictive cardiomyopathy can be caused by?

Answer 7

infiltrative diseases (eg, amyloidosis, sarcoidosis, hemochromatosis) and often results in diastolic heart failure due to ventricular hypertrophy with impaired ventricular filling.

Cardiac amyloidosis is characterized histologically by areas of myocardium infiltrated by an amorphous and acellular pink material (amyloid)

Question 8

What is the effect of pregnancy and the pituitary?

Answer 8

High estrogen levels during pregnancy cause enlargement of the pituitary gland without a proportional increase in blood supply.

Peripartum hypotension can cause ischemic necrosis of the pituitary leading to panhypopituitarism (Sheehan syndrome). Patients commonly develop failure of lactation due to deficiency of prolactin.

Question 9

What are the diagnostic tests for syphilis?

Answer 9

Syphilis is caused by the spirochete Treponema pallidum. Confirmation of the diagnosis requires 2 forms of serologic testing to prevent false-positive results.

Nontreponemal tests (eg, rapid plasma reagin, VDRL) evaluate for anticardiolipin antibodies (nonspecific); treponemal tests evaluate for antibodies targeted against T pallidum

Question 10

What are the watershed areas of the large intestine?

Answer 10

The splenic flexure and rectosigmoid junction lie between regions of perfusion of major arteries.

These “watershed” areas are susceptible to ischemic damage during hypotensive states, especially in patients with underlying arterial insufficiency

Question 11

Location of the caudate

Answer 11

The head of the caudate lies in the inferolateral wall of the frontal horn of the lateral ventricle.

It is separated from the globus pallidus and putamen by the internal capsule.

Atrophy of the caudate nuclei with enlargement of the lateral ventricles is characteristic of Huntington disease and can be observed on neuroimaging

Question 12

What is hereditary hemorrhagic telangiectasia?

Answer 12

presents with mucocutaneous telangiectasias, epistaxis, and visceral arteriovenous malformations (liver, lung, brain).

Lung involvement includes pulmonary AVMs (digital clubbing, platypnea) and pulmonary hypertension (a loud P2) due to high output heart failure from underlying systemic AVMs.

Question 13

Treatment of organophosphate poisoning?

Answer 13

Organophosphates inhibit cholinesterase in both muscarinic and nicotinic cholinergic synapses, leading to decreased acetylcholine degradation and overstimulation of the corresponding receptors.

Atropine reverses muscarinic effects but does not prevent the development of nicotinic effects such as muscle paralysis.

Pralidoxime is a cholinesterasae-reactiviting agent that allows for degradation of excess acetylcholine and treats both the muscarinic and nicotinic effects of organophosphates

Question 14

Function of germinal centers

Answer 14

Germinal centers are the sites where activated B cells proliferate and undergo affinity maturation during generation of humoral immune response.

The formation of multiple germinal centers is typically marked by lymphadenopathy, pain, and inflammation in the affected lymph node due to cellular recruitment and the release of inflammatory cytokines

Question 15

Digoxin toxicity presents with?

Answer 15

cardiac arrhythmias and nonspecific gastrointestinal (nausea, vomiting), neurological (confusion, weakness), and visual symptoms.

Elevated potassium is another sign of toxicity and is caused by inhibition of Na-K-ATPase pumps

Question 16

Initial empiric treatment of coagulase-negative staphylococcal infection should include?

Answer 16

vancomycin due to widespread methicillin resistance, especially in nosocomial infections.

If susceptibility results indicate a methicillin-susceptible isolate, vancomycin can be switched to nafcillin or oxacillin

Question 17

Lateral ankle sprain is due to?

Answer 17

inversion of a plantar-flexed foot and most commonly involves the anterior talofibular ligament.

Stronger forces can cause joint instability by injuring additional ligaments.

Question 18

Neonates versus adult body water

Answer 18

Neonates have a higher proportion of body water compared to adults. This can result in lower plasma concentrations of water-soluble drugs if they are administered at the same weight-based dosage as given to adult patients

Question 19

Pleural effusion causes what to tactile fremitus and breath sounds

Answer 19

Fluid in the pleural space acts to insulate sound vibrations that originate in the airways; therefore, pleural effusion causes decreased tactile fremitus and decreased intensity of breath sounds.

The high density of pleural fluid compared to normal lung tissue also causes dullness to percussion

Question 20

What is atopic dermatitis (eczema)?

Answer 20

Atopic dermatitis is a common, chronic inflammatory disorder caused by impairment of the skin’s barrier funciton.

Eczema presents with pruritus and erythematous papules and plaques and is associated with other atopic disease, such as allergic rhinitis and asthma

Question 21

Stress related mucosal disease is usually caused by?

Answer 21

local ischemia in the setting of severe physiologic stress (eg, shock, extensive burns, sepsis, severe trauma). Ulcers arising in the setting of severe trauma/burns are called Curling ulcers. Ulcers arising from intracranial injury are caused by direct vagal stimulation and are called Cushing ulcers

Question 22

What are risk factors for candidemia?

Answer 22

The presence of a central vascular catheter and receipt of parenteral nutrition are risk factors for candidemia.

Candida display a morphology of branching pseudohyphae with blastoconidia

Question 23

What is the main mechanism underlying all types of renal stones

Answer 23

Urine supersaturation is the main mechanism underlying all types of renal stones.

Low fluid intake increases the concentration of stone-forming agents, thereby promoting stone formation. All patients with nephrolithiasis should be advised to maintain adequate fluid intake

Question 24

What is a lipoma?

Answer 24

Lipomas are common, benign tumors that arise from the subcutaneous fat and present as soft, mobile masses that are stable or enlarge slowly over time. The diagnosis is usually made clinically, but histopath shows well-differentiated, mature adipocytes with a fibrous capsule

Question 25

What is a pleural effusion?

Answer 25

a collection of fluid between the visceral pleura that lines the lungs and the parietal pleura that lines the thoracic cavity. The fluid acts to insulate vibrations and sounds that originate in the airways of the lung; therefore, tactile fremitus and breath sounds are decreased over a pleural effusion. Dullness to percussion is also present.

Question 26

What is locked in syndrome

Answer 26

Ischemic injury to the bilateral ventral pons can lead to locked-in syndrome, a condition in which patients are unable to move or speak (due to interruption of the corticospinal and corticobulbar tracts) but retain consciousness, sensation, eye opening, and vertical eye movements

Question 27

What is hematogenous osteomyelitis?

Answer 27

occurs most commonly in children. It usually affects the metaphysis of long bones due to the presence of slow-flowing sinusoids that are conducive to bacterial seeding. Fever and refusal to bear weight are common in young children who are unable to localize the pain.

Question 28

What is responsible for the thrombotic and thromboembolic complications of nephrotic syndrome?

Answer 28

Neprotic syndrome is a hyper coagulable state. Sudden-onest abdominal or flank pain, hematuria and left sided varicoceles suggest renal vein thrombosis, a well known complication of nephrotic syndrome. Loss of anticoagulant factors, especially antithrombin III, is responsible for the thrombotic and thromboembolic complications of nephrotic syndrome

Question 29

Mutations of fas receptor leads to

Answer 29

The fas receptor acts to initiate the extrinsic pathway of apoptosis. Mutations involving the Fas receptor or Fas ligand can prevent apoptosis of autoreactive lymphocytes, thereby increasing the risk of autoimmune disorders such as systemic lupus erythematosus

Question 30

What processes occur in the mitochondria versus the cytosol?

Answer 30

Cellular compartmentalization allows multiple biochemical processes to occur simultaneously at maximum efficiency. Beta-oxidation of fatty acids, the TCA cycle, and the carboxylation of pyruvate (gluconeogenesis) all occur within the mitochondria. The enzymes responsible for glycolysis, fatty acid synthesis, and the pentose phosphate pathway reside in the cytosol

Question 31

What can increase GFR and decrease it?

Answer 31

Increases in capillary hydrostatic pressure or the Bowman's space oncotic pressure will increase GFR, while increases in capillary oncotic pressure or Bowman's space hydrostatic pressure will decrease GFR. The filtration fraction can be calculated by dividing the GFR by the renal plasma flow (RPF). Increases in GFR or decrease in RPF will increase the FF.

Question 32

What is first line pharmacotherapy for moderate to severe alcohol use disorder?

Answer 32

The opioid antagonist natrexone, and works by preventing the reinforcing effects of alcohol use.

Question 33

What is poststreptococcal glomerulonephritis?

Answer 33

the most common cause of nephritic syndrome in children. Light microscopy demonstrates enlarged, hypercellular glomeruli. Labs: elevated antistreptococcal antibodies (eg, antistreptolysin O, anti-DNase B) and decreased C3 and total complement levels. C4 levels are usually normal.

Question 34

What is the pathogenesis of e coli sepsis?

Answer 34

Pathogenesis of e coli sepsis involved the release of lipopolysaccharide (endotoxin) from bacterial cells. Lipid A is the major virulence factor of lipopolysaccarides that induces macrophages to release cytokines (IL-1, tumor necrosis factor-alpha), leading to the manifestations of septic shock (end organ dysfunction)

Question 35

What is seen in left sided heart failure

Answer 35

Left sided heart failure is common following myocardial infarction affecting the left ventricle. The resulting accumulation of edema in the pulmonary interstitium makes the lungs heavy and stiff, restricting inspiratory expansion and decreasing lung compliance.

Question 36

Severe hypertension in retinal precapillary arterioles causes?

Answer 36

endothelial disruption, leakage of plasma into the arteriolar wall, and fibrinous necrosis. The necrotic vessels can then bleed into the nerve fiber layer, which can be seen on examination as dot or flamed shaped hemorrhages

Question 37

Inflammatory bowel disease, especially ulcerative pancolitis, is associated with a significant risk for?

Answer 37

colorectal carcinoma. Compared with sporadic colorectal cancer, colitis-associated colorectal cancer is more likely to occur at a younger age, is typically more aggressive with a higher histopathologic grade, often evolves from flat (nonpolypoid) lesions, and is frequently multifocal. patients should be monitored regularly via colonoscopy with random biopsies

Question 38

What is the most common cause of familial dilated cardiomyopathy?

Answer 38

Autosomal dominant mutations in the TTN gene, which encodes for the sarcomere protein titin

Question 39

What is seen in orbitofrontal cortex injury?

Answer 39

Patients with orbitofrontal cortex injury often experience personality changes, disinhibition, and irritability secondary to impairment of the behavioral and emotional modulatory systems

Question 40

What is dumping syndrome?

Answer 40

The pyloric sphincter prevents incompletely digested hyperosmolar food particles from entering the intestines too rapidly; when the sphincter is bypassed or surgically removed, dumping syndrome may occur. Symptoms are related to excessive intestinal fluid (eg, abdominal cramps, diarrhea, nausea), vasomotor hyperactivity (eg, diaphoresis, palpitations, flushing) and intravascular volume depletion (eg, hypotension, tachycardia)

Question 41

What is the meaning of a p value <0.05?

Answer 41

A result is considered statistically significant if the 95% confidence interval does not cross the null value, which corresponds to a p-value <0.05

Question 42

Classic triad of congenital rubella syndrome

Answer 42

cataracts, sensorineural hearing loss, and patent ductus arteriosis. Prevention consists of maternal preconception immunization with live attenuated rubella vaccine

Question 43

Histopath of asbestosis?

Answer 43

Asbestosis is a pneumoconiosis that occurs with inhalation of asbestos fibers, most commonly in patients with occupational exposure (eg, insulation installation, shipbuilding, pipework). histopath: diffuse interstitial fibrosis and ferruginous asbestos bodies (translucent fibers coated with a golden iron-containing material). Pleural disease (eg, plaques, benign effusions) is common.

Question 44

Myocardial infarction on cardiac function curve

Answer 44

Myocardial infarction causes a sharp decrease in cardiac output due to loss of function of a zone of myocardium. On a cardiac function curve, myocardial infarction would decrease both the slope and the maximal height of the line

Question 45

What is Paget disease of bone?

Answer 45

characterized by disordered bone formation. Involvement of long bones can lead to bone pain, bowing, fracture, or arthritis of adjacent joints. Serum alkaline phosphatase is elevated due to increased production of new bone, but calcium and phosphorus levels remain normal

Question 46

Patients with long-standing, poorly controlled diabetes mellitus are high risk for developing?

Answer 46

distal symmetric polyneuropathy (diabetic neuropathy). Symptoms generally include progressive numbness, tingling, and burning/stabbing pain in the feet and/or toes that progresses proximally. Painful neuropathy is treated with serotonin-norepinephrine reuptake inhibitors, gabapentinoids, or tricyclic antidepressants

Question 47

What is the virulence factor of neisseria meningitidis in sepsis?

Answer 47

Neisseria meningitidis can cause sepsis and rapid circulatory collapse in previously healthy young individuals. Lipooligosaccharide, a virulence factor in the pathogen's outer membrane, is the major underlying cause of disease severity.

Question 48

Red blood cell fragments, burr cells, and helmet cells are associated with?

Answer 48

either microangiopathic hemolytic anemia or mechanical red cell destruction. In patietns with prosthetic valves, red blood cells are exposed to excessive shear and turbulence in the circulation, causing damage from mechanical trauma

Question 49

Chronic opioid use leads to the development of?

Answer 49

tolerance to analgesic effects and most side effects, with the exception of constipation and miosis. To prevent bowel complications, it is recommended that patients be treated prophylactically with adequate fluid intake and daily laxatives.

Question 50

What is henoch-schonlein purpura?

Answer 50

an IgA mediated leukocytoclastic vasculitis that commonly causes lower extremity palpable purpura, abdominal pain (+- gastrointestinal bleeding), renal disease (eg, hematuria) and joint pain

Question 51

MOA of carbonic anhydrase inhibitors (eg acetazolamide)

Answer 51

are weak diuretics that block reabsorption of sodium bicarbonate (NaHCO3) in the proximal tubule. The main effect is increased HCO3 excretion, leading to increased urine pH, mild metabolic acidosis (with compensatory respiratory alkalosis), mild hypokalemia, and mild hypocalcemia

Question 52

Teratogenic effects of valproate

Answer 52

Valproate is a teratogenic medication that decreases maternal folate levels and increases the risk of fetal neural tube defects (eg, meningocele, myelomeningocele)

Question 53

What is idiopathic pulmonary fibrosis?

Answer 53

an interstitial lung disease characterized by chronic progressive dyspnea, nonproductive cough, inspiratory crackles, and subpleural (peripheral) lung honeycombing. In IPF, repetitive micro injury to the alveolar epithelium (smoking, acid reflux) is focally repaired by fibroblast proliferation/collagen deposition instead of normal restoration via type 2 pneumocyte differentiation

Question 54

Pupillary asymmetry (anisocoria) is caused by

Answer 54

a lesion in the ocular parasympathetic (pupillary constriction or sympathetic (pupillary dilation) pathways. If the pupillary asymmetry increases in a dim room, it indicates that the smaller right pupil is unable to dilate due to a lesion in the right oculosympathetic pathway

Question 55

Pudendal nerve injury during vaginal delivery leads to?

Answer 55

gradual denervation and weakness of the pelvic floor muscles. In combination with age-related tissue atrophy, this injury contributes to pelvic organ prolapse (cystocele)

Question 56

What is acute intermittent porphyria?

Answer 56

an autosomal dominant condition caused by porphobilinogen deaminase deficiency. Most patients remain asymptomatic, but a minority present with acute attacks characterized by abdominal pain and vomiting, peripheral neuropathy, neuropsychological symptoms, and reddish-brown urine. Treatment consists of intravenous glucose or heme preparations, which downregulate ALA synthase activity

Question 57

How does acute aortic dissection typically present?

Answer 57

with sudden-onset, severe chest pain that is sharp or tearing in nature. Upper extremity blood pressure asymmetry can result from extension of the dissection into other vessels. Extension into the pericardium can cause acute tamponade with reduced cardiac output and shock.

Question 58

What is Osgood-Schlatter disease?

Answer 58

Repetitive traction at the tibial tubercle due to quadriceps contractions can lead to avulsion and fragmentation of the tibial tubercle in skeletally immature children, causing Osgood-Schlatter disease

Question 59

Acute lung transplant rejection

Answer 59

is a cell mediated response involving T lymphocyte activation against donor antigens and typically occurs within 6 months of transplant. Affected patients can have shortness of breath, cough, and low grade fever. Lung biopsy reveals perivascular and peribronchiolar lymphocytic infiltrate and absence of epithelial cell viral inclusions (ruling out cytomegalovirus)

Question 60

What is a communicating hydrocephalus?

Answer 60

Symmetrical enlargement of the ventriculi is characteristic of communicating hydrocephalus. Communicating hydrocephalus usually occurs secondary to dysfunction or obliteration of subarachnoid villi. This dysfunction is usually a sequelae of meningeal infection (including tuberculosis meningitis) or subarachnoid/intraventricular hemorrhage)

Question 61

Heparin-induced thrombocytopenia and thrombosis results from?

Answer 61

results from the production of IgG antibodies against complexes of heparin and platelet factor-4. The Fc component of these antibodies binds to platelets, resulting in widespread platelet activation and a prothrombotic state.

Question 62

What beta2-microglobulin

Answer 62

Beta2-microglobulin is renally cleared and poorly dialyzed. It accumulates as amyloid in dialysis patients, increasing in prevalence with dialysis duration, and has a predilection for osteoarticular surfaces. Shoulder pain and carpal tunnel syndrome are common. Bone cysts and pathologic fracures may also occur.

Question 63

What is friedreich ataxia?

Answer 63

AR condition that presents during childhood/adolescence with progressive gait ataxia (due to degeneration of the spinocerebellar tracts) and impaired joint and vibration sense (due to degeneration of the posterior columns and dorsal root ganglia). Other features include hypertrophic cardiomyopathy (most common cause of death), skeletal abnormalities (kyphoscoliosis, pes cavus), and diabetes mellitus

Question 64

Side effects of tricyclic antidepressants

Answer 64

Tricyclic antidepressants have strong anticholinergic properties. Potential side effects include confusion, constipation, and urinary retention. These meds should be used with caution in elderly patients

Question 65

Factors that promote formation of cholesterol stones

Answer 65

Most gallstones occur due to the supersaturation of cholesterol, which precipitates out of bile with mucin and calcium salts to form white or yellow cholesterol stones. Factors that promote the formation of cholesterol stones include increased cholesterol synthesis, gallbladder hypomotility, increased calcium or mucin concentration, and decreased bile acid synthesis or recirculation.

Question 66

What is phenylketonuria?

Answer 66

Intellectual disability, gait abnormalities, and a musty body odor are signs of phenylketonuria, an AR disorder. The probability that a child will inherit an autosomal recessive disease from heterozygous carrier parents is 1/4

Question 67

What is AA amyloidosis?

Answer 67

AA amyloidosis results from excessive serum amyloid A produced in rheumatoid arthritis and other chronic inflammatory conditions. Renal disease, the most common manifestation, presents as nephrotic syndrome. Light microscopy shows amorphous pink deposits with apple-green birefringence on Congo red stain under polarized light.

Question 68

What is the virulence of strep pneumo?

Answer 68

predominantly due to its polysaccharide capsule, which impedes phagocytosis and complement binding.

Question 69

What is seen in tumor lysis syndrome?

Answer 69

Patients with hematologic malignancies that have high tumor cell burdens or rapid turnover rates are at high risk for electrolyte abnormalities following the initiation of cytotoxic chemotherapy due to the massive lysis of tumor cells. Patients generally develop hyperphosphatemia, hyperkalemia, hyperkalemia, hyperuricemia, and elevated lactate dehydrogenase

Question 70

What is gender dysphoria?

Answer 70

characterized by a strong and persistent desire to live and be treated as another gender, which causes distress or impairment. It is often accompanied by a desire to change one's primary or secondary sexual characteristics

Question 71

What is type 1 HSR?

Answer 71

Type I HSR are an allergic response triggered by the binding of previously recognized antigen to IgE antibodies on mast cells. In the early phase of the response, histamine, already stored in preformed granules in mast cells, is the first chemical mediator released. Once released, histamine stimulates smooth muscle contraction (bronchoconstriction), increases vascular permeability (edema) and increases mucus secretion

Question 72

What is southern blotting?

Answer 72

a technique used to identify DNA mutations. It involves restriction endonuclease digestion of sample DNA, gel electrophoresis, and gene identification with a labeled DNA probe

Question 73

Heparin increases the effect of?

Answer 73

Heparin is commonly used for the prevention of deep venous thrombosis in nonambulatory patients or those undergoing elective surgery, especially hip and knee surgery. Heparin increases the effect of the naturally occuring anticoagulant antithrombin III

Question 74

What is Zollinger Ellison syndrome?

Answer 74

Patients with zollinger-ellison syndrome develop peptic ulcer disease and parietal cell hyperplasia with gastric fold enlargement due to gastrin hypersecretion

Question 75

Subdural hematoma is due to?

Answer 75

Looks like a cresent on CT. Subdural hematoma occurs due to rupture of cortical bridging veins. In young patients, it results from a fall or motor vehicle accident, and manifests with gradual onset of headache and confusion. In elderly patients it may occur after a minor trauma and present with a variety of neurologic symptoms

Question 76

What is obstructive sleep apnea?

Answer 76

characterized by sleep related apnea/choking spells, loud snoring, disrupted sleep, excessive daytime somnolence, and symptoms that may overlap with depression (eg, low mood, fatigue, impaired concentration)

Question 77

Inferior surface of the heart is supplied by?

Answer 77

The inferior wall of the left ventricle forms most of the inferior (diaphragmatic) surface of the heart and is supplied by the posterior descending artery. In 85-90% of people, the posterior descending artery derives from the right coronary artery (right dominant coronary circulation)

Question 78

What is exercise-associated collapse?

Answer 78

typically occurs after intense exercise in well-conditioned athletes. It is characterized by loss of postural tone or syncope immediately following the cessation of exercise and occurs due to impaired venous return to the heart

Question 79

The most common cause of community acquired pneumonia in both HIV infected and HIV uninfected people

Answer 79

Strep pneumo. Risk of invasive pneumococcal disease is significantly increased in patients with HIV regardless of CD4 count

Question 80

What is polymyalgia rheumatica?

Answer 80

Polymyalgia rheumatica occurs in more than half of patients with temporal arteritis. It is characterized by neck, torso, shoulder, and pelvic girdle pain and morning stiffness. Fatigue, fever, and weight loss may also occur. Monocular vision loss is a common complication of temporal arteritis

Question 81

What is pure red cell aplasia?

Answer 81

a rare form of bone marrow failure characterized by severe anemia with reticulocytopenia and morphologically normal platelets and leukocytes. It is most common with thymoma, lymphocytic leukemia, and parvo B19 infection

Question 82

Mefloquine chemoprophylaxis for malaria must be continued for 4 weeks after return from a malaria-endemic region to ensure the elimination of?

Answer 82

hepatic schizonts (which mature in the liver over 8-30 days)

Question 83

What is the number needed to treat?

Answer 83

the number of patients that need to be treated with a medication to avoid an additional negative outcome. NNT is calculated by dividing 1 by the absolute risk reduction (the difference between the control and experimental group event rates) Lower NNT values represent more beneficial treatments.

Question 84

Histopath for chronic lymphocytic (hashimoto) thyroiditis

Answer 84

a common cause of primary hypothyroidism. Histopath: intense lymphoplasmacytic infiltrate, often with germinal centers. Residual follicles may be surrounded by Hurthle cells (large cells with granular, eosinophilic cytoplasm)

Question 85

What is seen in acute cardiac tamponade?

Answer 85

Blunt chest trauma can lead to several life-threatening cardiopulmonary injuries. Progresssive hypotension with tachycardia, jugular venous distension, and bilateral vesicular breath sounds suggest acute cardiac tamponade

Question 86

What is Dandy Walker malformation?

Answer 86

a developmental anomaly characterized by hypoplasia/absence of the cerebellar vermis and cystic dilation of the fourth ventricle with posterior fossa enlargement. Patients often present during infancy with developmental delay and progressive skull enlargement. Other features may include cerebellar dysfunction and non-communicating hydrocephalus

Question 87

What is a ganglion cyst?

Answer 87

a connective tissue outpouching arising from tendon sheaths and joint structures. It is typically round, firm, well circumscribed, and transilluminates on penlight. Most resolve spontaneously

Question 88

Function of the lessor omentum

Answer 88

The lesser omentum is a double layer of peritoneum that extends from the liver to the lesser curvature of the stomach and the beginning of the duodenum. It is divided into the hepatogastric and hepatoduodenal ligaments.

Question 89

What is eosinophilic granulomatosis with polyangiitis (Churg Strauss)?

Answer 89

a small to medium vessel vasculitis characterized by late onset asthma, rhinosinusitis, and eosinophilia. Mononeuritis multiplex due to involvement of the epineural vessels of peripheral nerves is common.

Question 90

What is aortic coarctation?

Answer 90

classically leads to lower extremity claudication and increased blood pressure in the arms compared to the legs. Over time, if the defect remains unrepaired, a compensatory collateral circulation develops and supplies blood to the descending aorta. Blood flow through collateral vessels creates a continuous murmur heard over the interscapular area

Question 91

What can increase the risk for sudden infant death syndrome?

Answer 91

Maternal tobacco use during pregnancy and secondhand smoke exposure are associated with an increased risk for SIDS. Pathophysiology of the association between smoke exposure and SIDS may relate to impaired arousal and cardiovascular response to stimuli (airflow obstruction)

Question 92

Frontal lobe function

Answer 92

The frontal lobes are involved in personality, language, motor functions, and executive functions (eg, abstraction). Frontal lobe function may be diagnosed by testing abstraction ability (asking about the similarities between two related objects)

Question 93

What is buspirone?

Answer 93

Buspirone is a nonbenzodiazepine anxiolytic used to treat generalized anxiety disorder. It has a slow onset of action, lacks muscle relaxant or anticonvulsants properties, and carries no risk of dependence

Question 94

Prostate cancer relation with the bone

Answer 94

Prostate cancer is common in older men and metastasizes primarily to bone due to bone-specific tumor adhesion molecules and receptor ligands on the cellular surface. Prostate cancer causes osteoblastic lesions that result in new bone growth. Biopsy would show disordered trabeculae and signs of prostate cancer such as irregular glands with enlarged nuclei and prominent nucleoli

Question 95

MOA of thiazide diuretics

Answer 95

Thiazide diuretics work by blocking NaCl symporters in the distal convoluted tubules, causing enhanced Na, Cl, and water excretion. Since only a small amount of filtered Na reaches the distal tubules, thiazides are not as efficacious as loop diuretics. Unlike loop diuretics, thiazides can cause hypercalcemia

Question 96

What is multiple sclerosis?

Answer 96

characterized by episodic, progressive neurologic deficits involving multiple anatomic regions within the central nervous system. Demyelinating plaques are commonly seen in hyperintense lesions on T2-weighted MRI of the brain and spinal cord. Common manifestations include optic neuritis, internuclear ophthalmoplegia, sensory deficits, and fatigue, which may worsen with heat exposure

Question 97

What is Wiskott-Aldrich syndrome

Answer 97

triad of eczema, thrombocytopenia, and combined B and T cell deficiency. Patients can have thrombocytopenia at birth, with eczema and repeated infections due to encapsulated and/or opportunistic organisms usually developing later around 6 to 12 months of age

Question 98

What is postoperative urinary retention?

Answer 98

Postoperative urinary retention, with incomplete bladder emptying, is a common complication thought to involve decreased micturition reflex activity, decreased contractility of the bladder detrusor, and/or increased vesical sphincter tone. This condition may be treated with a muscarinic agonist (bethanechol) or an alpha 1 blocking drug

Question 99

Most available rodenticides contain brodifacoum, a long acting 4-hydroxycoumarin derivative. A patient who has ingested a quantity of rodenticide sufficient to cause coagulopathy and abnormal bleeding requires?

Answer 99

immediate treatment with fresh frozen plasma in addition to vitamin K

Question 100

Pulmonary hypertension leads to?

Answer 100

Pulmonary hypertension should be suspected in young and otherwise healthy patients with fatigue, progressive dyspnea, atypical chest pain, or unexplained syncope. Long standing pulmonary hypertension leads to hypertrophy and/or dilation of the right ventricle (cor pulmonale)