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NMLE Integrated practice questions

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Question 1Basic Medical Sciences

A 24-year-old man sustains a fracture through the middle of the shaft of the humerus. Which nerve is most likely injured because of its close relation to the spiral groove?

  1. Ulnar nerve
  2. Axillary nerve
  3. Radial nerve Correct answer.
  4. Median nerve

Explanation

The radial nerve runs in the spiral groove on the posterior surface of the humeral shaft, so mid-shaft fractures commonly injure it and produce wrist drop. The other nerves lie farther from the shaft at this level.

Question 2Basic Medical Sciences

Which vessel is the principal arterial supply to the sinoatrial node in most people?

  1. Posterior descending artery from the left
  2. Left anterior descending artery
  3. Left circumflex artery
  4. Right coronary artery Correct answer.

Explanation

In the majority of individuals the sinoatrial node is supplied by a branch of the right coronary artery, which also supplies the atrioventricular node in most hearts. The left coronary branches supply the node only in a minority.

Question 3Basic Medical Sciences

During the cardiac cycle, which event immediately follows the closure of the atrioventricular valves?

  1. Isovolumetric ventricular contraction Correct answer.
  2. Closure of the semilunar valves
  3. Atrial systole
  4. Ventricular filling

Explanation

Once the AV valves close at the start of systole, all valves are shut and the ventricles contract without changing volume, which is isovolumetric contraction. Ejection begins only when ventricular pressure exceeds aortic pressure.

Question 4Basic Medical Sciences

A patient has metabolic acidosis with a normal anion gap. Which condition best fits this pattern?

  1. Lactic acidosis from shock
  2. Diarrhea with bicarbonate loss Correct answer.
  3. Ethylene glycol ingestion
  4. Diabetic ketoacidosis

Explanation

A normal anion gap acidosis results from loss of bicarbonate or failure to excrete acid, as in diarrhea. The other listed conditions add unmeasured anions and raise the anion gap.

Question 5Basic Medical Sciences

Which immunoglobulin is the first to be produced in a primary humoral immune response?

  1. IgM Correct answer.
  2. IgG
  3. IgE
  4. IgA

Explanation

IgM is the earliest antibody class produced in a primary response and is efficient at complement activation. Class switching to IgG occurs later in the same response.

Question 6Basic Medical Sciences

Which structure passes through the foramen ovale of the sphenoid bone?

  1. Mandibular division of the trigeminal nerve Correct answer.
  2. Optic nerve
  3. Maxillary division of the trigeminal nerve
  4. Facial nerve

Explanation

The foramen ovale transmits the mandibular division of the trigeminal nerve along with the lesser petrosal nerve and accessory meningeal artery. The maxillary division exits through the foramen rotundum.

Question 7Basic Medical Sciences

A deficiency of vitamin B12 produces a macrocytic anemia primarily because of impaired synthesis of which molecule?

  1. Heme porphyrin rings
  2. Hemoglobin globin chains
  3. Transferrin receptors
  4. DNA during erythroid maturation Correct answer.

Explanation

Vitamin B12 is required for methionine synthase activity, which regenerates tetrahydrofolate for thymidine synthesis; impaired DNA synthesis causes nuclear-cytoplasmic asynchrony and macrocytosis. Globin and heme synthesis are unaffected.

Question 8Basic Medical Sciences

Which phase of the cell cycle is the principal target of the spindle assembly checkpoint?

  1. Metaphase of mitosis Correct answer.
  2. G1 phase
  3. S phase
  4. G2 phase

Explanation

The spindle assembly checkpoint operates during metaphase, delaying anaphase until every kinetochore is attached to spindle microtubules. G1 and G2 checkpoints monitor DNA damage and cell size instead.

Question 9Basic Medical Sciences

A drug that inhibits the Na+/K+ ATPase pump in cardiac myocytes would have which immediate effect on the myocyte?

  1. Reduced sodium gradient and increased intracellular calcium via the Na+/Ca2+ exchanger Correct answer.
  2. Increased potassium efflux and hyperpolarization
  3. Immediate closure of L-type calcium channels
  4. Direct inhibition of troponin C

Explanation

Blocking the pump raises intracellular sodium, which reduces calcium extrusion by the Na+/Ca2+ exchanger, so intracellular calcium rises and contractility increases. This is the basis of cardiac glycoside action.

Question 10Basic Medical Sciences

Which lung volume or capacity cannot be measured by simple spirometry?

  1. Vital capacity
  2. Inspiratory reserve volume
  3. Residual volume Correct answer.
  4. Tidal volume

Explanation

Residual volume remains in the lung after maximal expiration and cannot be exhaled into a spirometer, so it is measured by helium dilution or body plethysmography. Tidal volume, reserve volumes, and vital capacity are all spirometric measures.

Question 11Basic Medical Sciences

A 60-year-old man has hypertension and hypokalemia. Which primary aldosteronism-related change in the kidney is most direct?

  1. Reduced hydrogen ion secretion
  2. Increased sodium reabsorption and potassium secretion in the distal nephron Correct answer.
  3. Increased proximal bicarbonate excretion
  4. Reduced water permeability in the collecting duct

Explanation

Aldosterone acts on principal cells of the distal nephron to increase ENaC-mediated sodium reabsorption and ROMK-mediated potassium secretion. This produces sodium retention, potassium loss, and metabolic alkalosis.

Question 12Basic Medical Sciences

Which enzyme is deficient in the most common form of glycogen storage disease that presents with fasting hypoglycemia and hepatomegaly?

  1. Glucose-6-phosphatase Correct answer.
  2. Hexokinase
  3. Pyruvate kinase
  4. Phosphofructokinase-1

Explanation

Von Gierke disease results from glucose-6-phosphatase deficiency, so the liver cannot release glucose from glycogen or gluconeogenesis, causing fasting hypoglycemia and hepatomegaly. Hexokinase and PFK-1 deficiencies do not cause this classic presentation.

Question 13Basic Medical Sciences

Which cranial nerve nucleus provides parasympathetic innervation to the parotid gland?

  1. Dorsal motor nucleus of the vagus
  2. Inferior salivatory nucleus Correct answer.
  3. Nucleus ambiguus
  4. Superior salivatory nucleus

Explanation

Preganglionic parasympathetic fibers for the parotid travel with the glossopharyngeal nerve from the inferior salivatory nucleus to the otic ganglion. The superior salivatory nucleus supplies the submandibular and sublingual glands.

Question 14Basic Medical Sciences

A 45-year-old woman develops fever, a new murmur, and petechiae. Blood cultures grow viridans streptococci. Which cardiac lesion is most characteristic of subacute infective endocarditis?

  1. Vegetations on previously damaged valves Correct answer.
  2. Myocardial abscesses from direct extension
  3. Mural thrombi in the left ventricle
  4. Fibrinous pericarditis

Explanation

Subacute endocarditis typically forms vegetations on valves already damaged by rheumatic disease or other scarring, which allows viridans streptococci to adhere. Acute endocarditis more often attacks previously normal valves with aggressive organisms.

Question 15Basic Medical Sciences

In a population, a screening test has high sensitivity but low specificity. Which consequence is expected?

  1. Perfect exclusion of disease when the test is negative
  2. Many false positives among unaffected individuals Correct answer.
  3. Many false negatives among affected individuals
  4. No change in positive predictive value with prevalence

Explanation

High sensitivity means few false negatives, but low specificity means many healthy people test positive, generating numerous false positives. Positive predictive value also falls when prevalence is low.

Question 16Basic Medical Sciences

A 70-year-old man has sudden painless loss of vision in one eye with a pale retina and a cherry-red spot at the macula. Which artery is occluded?

  1. Central retinal artery Correct answer.
  2. Ophthalmic artery proximal to the origin of the central retinal artery
  3. Central retinal vein
  4. Posterior ciliary artery

Explanation

Central retinal artery occlusion produces sudden painless monocular vision loss with a pale, edematous retina and a cherry-red spot where the choroidal circulation shows through the fovea. The findings are unilateral and not inflammatory.

Question 17Basic Medical Sciences

Which mechanism best explains why aminoglycosides are bactericidal against aerobic gram-negative rods but ineffective against anaerobes?

  1. They are inactivated by anaerobic ribosomes
  2. Their uptake requires an oxygen-dependent proton motive force Correct answer.
  3. They require anaerobic conditions for activation
  4. They bind only to gram-positive peptidoglycan

Explanation

Aminoglycoside entry into bacteria depends on an electron transport chain and proton motive force, which anaerobic organisms lack, so the drugs cannot reach their ribosomal target. This is why they are combined with beta-lactams for empiric coverage.

Question 18Basic Medical Sciences

A tumor suppressor gene is best described by which property?

  1. It is derived from a proto-oncogene by point mutation
  2. A single mutated allele is sufficient for oncogenic transformation
  3. It is inherited only through the maternal line
  4. Both alleles must typically be inactivated for loss of function Correct answer.

Explanation

Tumor suppressor genes follow the two-hit model, in which both alleles must be lost or inactivated for the function to disappear. Oncogenes, by contrast, are activated by a single gain-of-function change.

Question 19Basic Medical Sciences

Which change in the oxygen-hemoglobin dissociation curve would be expected in a patient with acidosis and fever?

  1. Rightward shift with increased P50 Correct answer.
  2. Increased hemoglobin oxygen affinity
  3. No change in P50
  4. Leftward shift with decreased P50

Explanation

Acidosis, fever, and raised 2,3-BPG shift the curve right, reducing affinity and increasing P50 so oxygen is released more readily to tissues. A leftward shift reflects increased affinity, as in alkalosis or hypothermia.

Question 20Basic Medical Sciences

A 55-year-old man has nephrotic syndrome with proteinuria, hypoalbuminemia, and hyperlipidemia. Which glomerular change is most consistent with minimal change disease?

  1. Normal light microscopy with podocyte foot process effacement on electron microscopy Correct answer.
  2. Segmental sclerosis of glomerular tufts
  3. Subendothelial immune complex deposits
  4. Crescents in Bowman space

Explanation

Minimal change disease shows normal glomeruli by light microscopy, with diffuse podocyte foot process effacement on electron microscopy. Crescents and subendothelial deposits indicate other forms of glomerulonephritis.

Question 21Basic Medical Sciences

Which hormone is the principal regulator of plasma calcium by increasing renal calcium reabsorption and bone resorption?

  1. Aldosterone
  2. Calcitonin
  3. Parathyroid hormone Correct answer.
  4. Insulin

Explanation

Parathyroid hormone raises plasma calcium by increasing renal calcium reabsorption, stimulating bone resorption, and promoting calcitriol synthesis. Calcitonin has the opposite effect on calcium.

Question 22Basic Medical Sciences

A child has recurrent pyogenic infections and is found to have defective oxidative burst in neutrophils. Which enzyme is most likely deficient?

  1. Catalase
  2. Superoxide dismutase
  3. NADPH oxidase Correct answer.
  4. Myeloperoxidase

Explanation

Chronic granulomatous disease results from deficiency of NADPH oxidase, which is required to generate superoxide for the respiratory burst. Myeloperoxidase deficiency is usually milder and does not produce the same infection pattern.

Question 23Basic Medical Sciences

Which feature distinguishes apoptosis from necrosis on histologic examination?

  1. Cell swelling with membrane rupture
  2. Extensive inflammation in surrounding tissue
  3. Loss of nuclear basophilia with preservation of cell size
  4. Cell shrinkage with chromatin condensation and apoptotic bodies Correct answer.

Explanation

Apoptosis is energy-dependent and produces cell shrinkage, chromatin condensation, and membrane-bound apoptotic bodies with minimal inflammation. Necrosis involves swelling, membrane rupture, and prominent inflammation.

Question 24Basic Medical Sciences

A 30-year-old woman has episodes of flushing, diarrhea, and wheezing and is found to have a small bowel tumor. Which substance is most directly responsible for the flushing and diarrhea?

  1. Serotonin Correct answer.
  2. Insulin
  3. Vasoactive intestinal peptide
  4. Gastrin

Explanation

Carcinoid syndrome results from serotonin and other mediators released by a carcinoid tumor, typically after liver metastases bypass hepatic metabolism. Serotonin drives flushing and diarrhea, and it can cause right-sided valvular fibrosis.

Question 25Basic Medical Sciences

A 65-year-old man has progressive dyspnea and is found to have restrictive lung disease. Which pattern of pulmonary function tests is expected?

  1. Normal total lung capacity with reduced diffusing capacity
  2. Increased vital capacity with airflow obstruction
  3. Increased residual volume with reduced FEV1/FVC ratio
  4. Reduced total lung capacity with preserved or increased FEV1/FVC ratio Correct answer.

Explanation

Restrictive disease reduces total lung capacity, and because airflow is not obstructed the FEV1/FVC ratio is normal or high. Obstructive disease instead reduces the ratio and raises residual volume.

Question 26Basic Medical Sciences

A 24-year-old man sustains a fracture through the surgical neck of the humerus. Which nerve is most likely injured, given its close relation to this part of the bone?

  1. Median nerve
  2. Radial nerve
  3. Musculocutaneous nerve
  4. Axillary nerve Correct answer.

Explanation

The axillary nerve winds around the surgical neck of the humerus together with the posterior circumflex humeral artery, so fractures at this site commonly injure it. It supplies the deltoid and teres minor and carries sensation over the lateral shoulder.

Question 27Basic Medical Sciences

A 58-year-old woman has a thyroid nodule. Cytology shows cells with abundant pale, granular cytoplasm and nuclei displaced to the periphery, giving a "Orphan Annie eye" appearance. Which diagnosis is most consistent with these findings?

  1. Follicular thyroid carcinoma
  2. Anaplastic thyroid carcinoma
  3. Medullary thyroid carcinoma
  4. Papillary thyroid carcinoma Correct answer.

Explanation

Papillary thyroid carcinoma is characterized by optically clear nuclei with peripherally marginated chromatin (Orphan Annie eye), nuclear grooves, and psammoma bodies, often with lymph node metastasis. It is the most common thyroid malignancy.

Question 28Basic Medical Sciences

A 30-year-old man develops fever, hypotension, and a diffuse erythematous rash during a staphylococcal infection. Which mechanism best explains the hypotension in this condition?

  1. Antibody deposition in renal glomeruli
  2. Superantigen-mediated polyclonal T-cell activation with cytokine release Correct answer.
  3. Complement-mediated lysis of erythrocytes
  4. Direct invasion of vascular smooth muscle by bacteria

Explanation

Toxic shock syndrome is caused by staphylococcal superantigens such as TSST-1, which cross-link MHC class II and T-cell receptors outside the normal antigen groove, activating many T cells and releasing massive cytokines. This produces fever, rash, and vasodilatory shock.

Question 29Basic Medical Sciences

A 62-year-old man has chronic hypertension. Which change in the arterial wall most directly predisposes to aortic dissection?

  1. Cystic medial degeneration with loss of elastic fibers Correct answer.
  2. Fibrinoid necrosis of arterioles
  3. Intimal atherosclerosis with plaque rupture
  4. Fibromuscular dysplasia of the renal arteries

Explanation

Aortic dissection typically results from degeneration of the tunica media with loss of smooth muscle and elastic fibers, creating a false lumen when the intima tears. Chronic hypertension accelerates this medial degeneration.

Question 30Basic Medical Sciences

A 40-year-old woman is given a drug that blocks the action of aldosterone at its receptor. Which change would be expected in the collecting duct?

  1. Increased hydrogen ion secretion
  2. Increased sodium reabsorption and potassium secretion
  3. Decreased sodium reabsorption and decreased potassium secretion Correct answer.
  4. Increased water reabsorption independent of ADH

Explanation

Aldosterone normally increases ENaC-mediated sodium reabsorption and promotes potassium secretion in principal cells of the collecting duct. Blocking its receptor reduces both sodium reabsorption and potassium secretion, causing natriuresis and hyperkalemia.

Question 31Basic Medical Sciences

A 6-year-old child has recurrent respiratory infections and is found to have defective mucociliary clearance with thick secretions. Which mechanism best explains the impaired clearance?

  1. Loss of ciliated epithelium in the trachea
  2. Decreased chloride secretion and increased sodium absorption with dehydrated mucus Correct answer.
  3. Autoantibody destruction of alveolar type II cells
  4. Deficiency of surfactant protein B

Explanation

In cystic fibrosis, defective CFTR chloride channels reduce chloride secretion and increase sodium and water absorption, producing thick, dehydrated mucus that impairs mucociliary clearance. This leads to recurrent airway infections and bronchiectasis.

Question 32Basic Medical Sciences

A 55-year-old man with alcohol use disorder has fasting hypoglycemia and elevated liver enzymes. Which biochemical finding best supports impaired gluconeogenesis?

  1. Elevated free fatty acids with normal glucose
  2. Elevated insulin with low blood glucose
  3. Elevated ketones with low blood glucose
  4. Elevated lactate with low blood glucose Correct answer.

Explanation

Gluconeogenesis consumes lactate, so impaired hepatic gluconeogenesis leads to lactate accumulation together with hypoglycemia. Alcohol metabolism also increases NADH, shifting pyruvate toward lactate and limiting gluconeogenic substrates.

Question 33Basic Medical Sciences

A 28-year-old woman has a history of recurrent pregnancy loss and is found to have antiphospholipid antibodies. Which mechanism best explains the thrombosis risk?

  1. Deficiency of antithrombin III
  2. Antibody-mediated activation of endothelial cells and platelets Correct answer.
  3. Deficiency of vitamin K-dependent clotting factors
  4. Increased fibrinolysis

Explanation

Antiphospholipid antibodies promote a prothrombotic state by activating endothelial cells, platelets, and complement and by interfering with annexin A5 and beta-2 glycoprotein I. This causes both arterial and venous thrombosis as well as pregnancy loss.

Question 34Basic Medical Sciences

A 50-year-old man has a chronic cough and is found to have a tumor arising from the apex of the lung. Which structure is most likely to be compressed, producing Horner syndrome?

  1. Sympathetic chain Correct answer.
  2. Phrenic nerve
  3. Vagus nerve
  4. Recurrent laryngeal nerve

Explanation

Apical lung tumors (Pancoast tumors) can compress the cervical sympathetic chain, causing ipsilateral ptosis, miosis, and anhidrosis. They may also involve the brachial plexus and subclavian vessels.

Question 35Basic Medical Sciences

A 35-year-old woman has fatigue, weight gain, and cold intolerance. Which laboratory finding best supports primary hypothyroidism?

  1. Low TSH and low free T4
  2. High TSH and low free T4 Correct answer.
  3. High TSH and high free T4
  4. Low TSH and high free T4

Explanation

In primary hypothyroidism, the thyroid gland fails to produce sufficient T4, and the loss of negative feedback causes the pituitary to secrete more TSH. Thus TSH is elevated while free T4 is low.

Question 36Basic Medical Sciences

A 65-year-old man has a serum sodium of 120 mmol/L and is found to have inappropriate ADH secretion. Which change best explains the hyponatremia?

  1. Increased renal water reabsorption with dilution of body fluids Correct answer.
  2. Increased renal sodium loss with normal water balance
  3. Decreased ADH secretion
  4. Decreased total body water

Explanation

In SIADH, excess ADH increases aquaporin-2-mediated water reabsorption in the collecting duct, expanding total body water and diluting serum sodium. The result is euvolemic hyponatremia with concentrated urine.

Question 37Basic Medical Sciences

A 45-year-old man has a deep wound contaminated with soil. Which organism is most likely to cause an anaerobic wound infection with a characteristic gram-positive rod and spores?

  1. Escherichia coli
  2. Staphylococcus aureus
  3. Clostridium perfringens Correct answer.
  4. Pseudomonas aeruginosa

Explanation

Clostridium perfringens is a gram-positive, spore-forming, anaerobic rod found in soil and is a classic cause of gas gangrene in contaminated wounds. It produces alpha-toxin, a phospholipase that damages cell membranes.

Question 38Basic Medical Sciences

A 70-year-old woman has a sudden loss of vision in one eye with a cherry-red spot at the macula. Which arterial territory is most likely occluded?

  1. Central retinal vein
  2. Central retinal artery Correct answer.
  3. Ophthalmic artery proximal to the globe
  4. Posterior cerebral artery

Explanation

Central retinal artery occlusion produces sudden painless monocular vision loss with a pale, opacified retina and a cherry-red spot at the fovea, where the thin retina allows the choroidal circulation to show through.

Question 39Basic Medical Sciences

A 30-year-old woman has a history of recurrent infections and is found to have defective neutrophil oxidative burst. Which enzyme is most likely deficient?

  1. Superoxide dismutase
  2. Myeloperoxidase
  3. Glucose-6-phosphatase
  4. NADPH oxidase Correct answer.

Explanation

Chronic granulomatous disease results from defective NADPH oxidase, which prevents the respiratory burst and superoxide production needed to kill catalase-positive organisms. Patients develop recurrent infections with organisms such as Staphylococcus aureus and Aspergillus.

Question 40Basic Medical Sciences

A 22-year-old man has a mutation that prevents the normal degradation of cyclins. Which consequence best describes the effect on the cell cycle?

  1. Arrest at the G2 checkpoint
  2. Failure of DNA replication
  3. Prolonged activation of cyclin-dependent kinases with uncontrolled progression Correct answer.
  4. Loss of mitotic spindle formation

Explanation

Cyclins must be degraded for cyclin-dependent kinases to be inactivated and for the cell to exit mitosis. If cyclins persist, CDK activity remains high, driving continuous cell-cycle progression and contributing to oncogenesis.

Question 41Internal Medicine

A 58-year-old man with type 2 diabetes has an eGFR of 32 mL/min/1.73 m². Which oral glucose-lowering agent should be avoided because of reduced clearance and risk of lactic acidosis?

  1. Empagliflozin
  2. Metformin Correct answer.
  3. Sitagliptin
  4. Pioglitazone

Explanation

Metformin is cleared renally, and accumulation in advanced chronic kidney disease raises the risk of metformin-associated lactic acidosis. Most guidance advises stopping it when eGFR falls below 30 mL/min/1.73 m² and reducing the dose between 30 and 45. The other agents listed do not carry a lactic acidosis risk of this kind.

Question 42Internal Medicine

A 24-year-old woman presents with palpitations, heat intolerance, and weight loss. TSH is suppressed and free T4 is elevated. Which finding on examination most specifically supports Graves disease over a toxic nodule?

  1. Diffuse goiter with a bruit Correct answer.
  2. Family history of thyroid disease
  3. A single palpable thyroid nodule
  4. Tenderness of the thyroid gland

Explanation

Graves disease is caused by TSH-receptor stimulating antibodies that produce a diffusely enlarged, hypervascular gland, so an audible bruit over the thyroid is characteristic. A solitary nodule suggests a toxic adenoma, and tenderness suggests subacute thyroiditis. Family history is supportive but not specific.

Question 43Internal Medicine

Which electrocardiographic finding is most characteristic of acute pericarditis?

  1. ST elevation confined to leads V1 to V4
  2. Sawtooth flutter waves
  3. Diffuse ST-segment elevation with PR depression Correct answer.
  4. Deep Q waves in inferior leads

Explanation

Acute pericarditis inflames the entire pericardium, producing widespread concave ST elevation and reciprocal PR depression across many leads. ST elevation limited to an anterior territory reflects myocardial infarction rather than pericarditis. Q waves indicate necrosis and sawtooth waves indicate atrial flutter.

Question 44Internal Medicine

A 67-year-old man has a blood pressure of 158/96 mmHg confirmed on two visits. He has no diabetes, kidney disease, or other comorbidity. According to standard hypertension guidance, which class is recommended as first-line therapy?

  1. Loop diuretic
  2. Central alpha-2 agonist
  3. Alpha-1 blocker
  4. Thiazide-type diuretic Correct answer.

Explanation

Thiazide-type diuretics, ACE inhibitors, angiotensin receptor blockers, and dihydropyridine calcium channel blockers are all acceptable first-line agents for uncomplicated hypertension. Alpha blockers, central agonists, and loop diuretics are reserved for specific indications or resistant disease. Starting with a thiazide is therefore appropriate and evidence-based.

Question 45Internal Medicine

A 45-year-old woman has a microcytic anemia with a low ferritin. Which additional finding is most consistent with iron deficiency anemia?

  1. Elevated serum ferritin
  2. Ring sideroblasts on marrow aspirate
  3. Elevated total iron-binding capacity Correct answer.
  4. Elevated transferrin saturation

Explanation

In iron deficiency, low iron stores drive a compensatory rise in transferrin, so total iron-binding capacity increases while transferrin saturation falls. Ferritin is depleted rather than elevated. Ring sideroblasts indicate defective heme synthesis, as in sideroblastic anemia.

Question 46Internal Medicine

A 70-year-old man has an acute exacerbation of COPD with increased dyspnea and purulent sputum. Which intervention most reliably improves survival in this setting when hypoxemia is present?

  1. Controlled supplemental oxygen to a target saturation of 88 to 92 percent Correct answer.
  2. Chest physiotherapy
  3. High-flow oxygen to a target saturation above 98 percent
  4. Routine systemic corticosteroids alone

Explanation

In acute COPD exacerbation with hypoxemia, controlled oxygen therapy targeting 88 to 92 percent improves tissue oxygenation while avoiding hyperoxia-induced hypercapnia. Corticosteroids and bronchodilators reduce symptoms but have not been shown to reduce mortality. Unrestricted oxygen can worsen hypercapnia.

Question 47Internal Medicine

A 30-year-old man has sudden severe epigastric pain radiating to the back with vomiting. Serum lipase is three times the upper limit of normal. Which is the most common cause of this condition in developed countries?

  1. Gallstones Correct answer.
  2. Hypertriglyceridemia
  3. Endoscopic retrograde cholangiopancreatography
  4. Hypercalcemia

Explanation

Gallstones and alcohol account for the majority of acute pancreatitis cases, with gallstones the leading cause in most developed countries. Hypertriglyceridemia, post-ERCP injury, and hypercalcemia are recognized but less frequent causes. The presentation with elevated lipase is diagnostic of acute pancreatitis.

Question 48Internal Medicine

A 55-year-old woman reports fatigue and cold intolerance. TSH is elevated and free T4 is low. Which electrocardiographic abnormality is most likely?

  1. Sinus bradycardia with low-voltage QRS complexes Correct answer.
  2. Atrial fibrillation with rapid ventricular response
  3. Shortened QT interval
  4. ST elevation in leads II, III, and aVF

Explanation

Hypothyroidism slows conduction and reduces myocardial contractility, producing sinus bradycardia and low-voltage QRS complexes. It can also prolong the QT interval. Rapid atrial fibrillation and localized ST elevation are not typical of untreated hypothyroidism.

Question 49Internal Medicine

A 62-year-old man with heart failure and reduced ejection fraction remains symptomatic despite an ACE inhibitor and beta blocker. Which addition has been shown to reduce mortality in this population?

  1. Mineralocorticoid receptor antagonist Correct answer.
  2. Digoxin
  3. Dihydropyridine calcium channel blocker
  4. Amiodarone

Explanation

Mineralocorticoid receptor antagonists such as spironolactone reduce mortality in heart failure with reduced ejection fraction when added to standard therapy. Digoxin reduces hospitalizations but not mortality. Amiodarone and dihydropyridine calcium channel blockers are not mortality-reducing agents in this setting.

Question 50Internal Medicine

A 48-year-old woman has proximal muscle weakness, a heliotrope rash, and Gottron papules. Which malignancy screening approach is most appropriate?

  1. No cancer screening because the diagnosis is benign
  2. Immediate whole-body PET scan in all patients
  3. Age-appropriate cancer screening plus evaluation for occult malignancy Correct answer.
  4. Screening limited to breast and cervical cancer

Explanation

Dermatomyositis, particularly in adults, carries an increased risk of underlying malignancy, so age-appropriate screening and evaluation for occult cancer are recommended. Routine whole-body imaging in every patient is not universally mandated. The condition is autoimmune, not benign, and screening should not be restricted to gynecologic cancers.