An x-ray of the chest shows an extensive consolidation within the right lower lobe consistent with lobar pneumonia. Sputum and blood cultures are sent to the laboratory for analysis, and empiric antibiotic treatment with intravenous cefotaxime is begun. Which of the following is most likely to have prevented this patient's pneumonia?
Q942
A 62-year-old man comes to the physician because of a persistent cough for the past 2 weeks. During this time, he has also had occasional discomfort in his chest. Three weeks ago, he had a sore throat, headache, and a low-grade fever, which were treated with acetaminophen and rest. He has a history of hypertension and hyperlipidemia. His father died of myocardial infarction at the age of 57 years. He has smoked a pack of cigarettes daily for the past 40 years. Current medications include enalapril and atorvastatin. His temperature is 37°C (98.6°F), pulse is 70/min, and blood pressure is 145/90 mm Hg. Physical examination shows no abnormalities. An x-ray of the chest is shown. Which of the following is the most appropriate next step in management?
Q943
A 35-year-old man comes to the physician because of a rash on the thigh for 10 days. He reports that the rash has been enlarging and is intensely itchy. Two weeks ago, he adopted a stray dog from an animal shelter. Vital signs are within normal limits. A photograph of the examination findings is shown. Which of the following is the most likely cause of this patient's symptoms?
Q944
A 74-year-old African-American woman is brought to the emergency department by her home health aid. The patient was eating breakfast this morning when she suddenly was unable to lift her spoon with her right hand. She attempted to get up from the table, but her right leg felt weak. One hour later in the emergency department, her strength is 0/5 in the right upper and right lower extremities. Strength is normal in her left upper and lower extremities. Sensation is normal bilaterally. An emergency CT of the head does not show signs of hemorrhage. Subsequent brain MRI shows an infarct involving the internal capsule. Which of the following is true about her disease process?
Q945
A 68-year-old man is admitted to the intensive care unit after open abdominal aortic aneurysm repair. The patient has received 4 units of packed red blood cells during the surgery. During the first 24 hours following the procedure, he has only passed 200 mL of urine. He has congestive heart failure and hypertension. Current medications include atenolol, enalapril, and spironolactone. He appears ill. His temperature is 37.1°C (98.8°F), pulse is 110/min, respirations are 18/min, and blood pressure is 110/78 mm Hg. Examination shows dry mucous membranes and flat neck veins. The remainder of the examination shows no abnormalities. Laboratory studies show a serum creatinine level of 2.0 mg/dL and a BUN of 48 mg/dL. His serum creatinine and BUN on admission were 1.2 mg/dL and 18 mg/dL, respectively. Further evaluation of this patient is most likely to reveal which of the following findings?
Q946
A 15-year-old girl is hospitalized because of increased fatigue and weight loss over the past 2 months. The patient has no personal or family history of a serious illness. She takes no medications, currently. Her blood pressure is 175/74 mm Hg on the left arm and 90/45 on the right. The radial pulse is 84/min but weaker on the right side. The femoral blood pressure and pulses show no abnormalities. Temperature is 38.1℃ (100.6℉). The muscles over the right upper arm are slightly atrophic. The remainder of the examination reveals no abnormalities. Laboratory studies show the following results:
Hemoglobin 10.4 g/dL
Leukocyte count 5,000/mm3
Erythrocyte sedimentation rate 58 mm/h
Magnetic resonance arteriography reveals irregularity, stenosis, and poststenotic dilation involving the proximal right subclavian artery. Prednisone is initiated with improvement of her symptoms. Which of the following is the most appropriate next step in the patient management?
Q947
A 37-year-old woman accompanied by her husband presents to the emergency department after loss of consciousness 30 minutes ago. The husband reports that she was sitting in a chair at home and began having sustained rhythmic contractions of all 4 extremities for approximately 1 minute. During transport via ambulance she appeared confused but arousable. Her husband reports she has no medical conditions, but for the past 2 months she has occasionally complained of episodes of sweating, palpitations, and anxiety. Her brother has epilepsy and her mother has type 1 diabetes mellitus. Laboratory studies obtained in the emergency department demonstrate the following:
Serum:
Na+: 136 mEq/L
K+: 3.8 mEq/L
Cl-: 100 mEq/L
HCO3-: 19 mEq/L
BUN: 16 mg/dL
Creatinine: 0.9 mg/dL
Glucose: 54 mg/dL
C-peptide: Low
Which of the following is the most likely diagnosis?
Q948
A 26-year-old man presents to his primary care physician complaining of impotence. He reports that he has a healthy, long-term relationship with a woman whom he hopes to marry, but he is embarrassed that he is unable to have an erection. Which of the following is the next best step?
Q949
A 75-year-old man comes to the physician because of a 4-month history of progressive shortness of breath and chest pressure with exertion. Cardiac examination shows a crescendo-decrescendo systolic murmur that is heard best in the second right intercostal space. Radial pulses are decreased and delayed bilaterally. Transesophageal echocardiography shows hypertrophy of the left ventricle and a thick, calcified aortic valve. The area of the left ventricular outflow tract is 30.6 mm2. Using continuous-wave Doppler measurements, the left ventricular outflow tract velocity is 1.0 m/s, and the peak aortic valve velocity is 3.0 m/s. Which of the following values most closely represents the area of the stenotic aortic valve?
Q950
A 53-year-old woman comes to the physician because of progressive headache and fatigue for the past 2 months. One year ago, she was diagnosed with Cushing disease, which was ultimately treated with bilateral adrenalectomy. Current medications are hydrocortisone and fludrocortisone. Examination shows generalized hyperpigmentation of the skin and bitemporal visual field defects. Serum studies show an ACTH concentration of 1250 pg/mL (N = 20–100). Which of the following is the most appropriate next step in management?
Cardiology US Medical PG Practice Questions and MCQs
Question 941: An x-ray of the chest shows an extensive consolidation within the right lower lobe consistent with lobar pneumonia. Sputum and blood cultures are sent to the laboratory for analysis, and empiric antibiotic treatment with intravenous cefotaxime is begun. Which of the following is most likely to have prevented this patient's pneumonia?
A. Rapid sequence induction
B. Prolonged bed rest
C. Smoking cessation
D. Perioperative antibiotic prophylaxis
E. Incentive spirometry (Correct Answer)
Explanation: ***Incentive spirometry***
- **Incentive spirometry** encourages deep breathing and helps prevent **atelectasis** and **pneumonia**, especially in postoperative or immobilized patients.
- It improves **lung volume** and promotes the clearance of respiratory secretions.
- This is the **most direct preventive measure** in the immediate perioperative or hospitalization period to reduce risk of hospital-acquired pneumonia.
*Rapid sequence induction*
- **Rapid sequence intubation** is a procedure used to quickly and safely secure the airway, reducing the risk of **aspiration** during intubation.
- While it may prevent aspiration pneumonia specifically, it does not prevent lobar pneumonia from other causes and is not a prophylactic measure against general hospital-acquired pneumonia.
*Prolonged bed rest*
- **Prolonged bed rest** actually **increases** the risk of developing **pneumonia** and **atelectasis** due to reduced lung expansion and impaired clearance of secretions.
- It leads to hypoventilation in dependent lung areas and can worsen respiratory function.
*Smoking cessation*
- While **smoking cessation** does help prevent pneumonia by improving mucociliary clearance and reducing susceptibility to respiratory infections, it is a **long-term preventive measure** rather than an immediate intervention.
- In the context of **preventing postoperative or hospital-acquired pneumonia**, smoking cessation would need to occur well before hospitalization to have significant effect.
- **Incentive spirometry** provides more immediate protection in the acute hospital setting.
*Perioperative antibiotic prophylaxis*
- **Perioperative antibiotic prophylaxis** is designed to prevent **surgical site infections**, not hospital-acquired pneumonia.
- It targets specific bacteria associated with the surgical procedure and wound contamination, not general respiratory pathogens causing lobar pneumonia.
- Routine antibiotic prophylaxis does not cover typical pneumonia pathogens unless specifically indicated.
Question 942: A 62-year-old man comes to the physician because of a persistent cough for the past 2 weeks. During this time, he has also had occasional discomfort in his chest. Three weeks ago, he had a sore throat, headache, and a low-grade fever, which were treated with acetaminophen and rest. He has a history of hypertension and hyperlipidemia. His father died of myocardial infarction at the age of 57 years. He has smoked a pack of cigarettes daily for the past 40 years. Current medications include enalapril and atorvastatin. His temperature is 37°C (98.6°F), pulse is 70/min, and blood pressure is 145/90 mm Hg. Physical examination shows no abnormalities. An x-ray of the chest is shown. Which of the following is the most appropriate next step in management?
A. Endovascular repair
B. Arteriography
C. CT scan of the chest (Correct Answer)
D. Genetic testing
E. Esophageal manometry
Explanation: ***CT scan of the chest***
- The patient's presentation with **persistent cough**, **chest discomfort**, and a **history of heavy smoking** (40 pack-years) raises significant concern for serious underlying pulmonary or cardiovascular pathology
- Given that the chest X-ray shows an abnormality, **CT scan of the chest** is the most appropriate next step to better characterize the findings
- CT imaging can help diagnose conditions such as **lung cancer** (high risk given smoking history), **aortic aneurysm** (given family history and risk factors), **pulmonary embolism**, or other thoracic pathology
- CT provides superior detail compared to plain radiography and is the standard diagnostic approach when chest X-ray findings are abnormal or concerning
*Endovascular repair*
- This is a **therapeutic intervention** used to treat conditions like aortic aneurysms or vascular abnormalities, not a diagnostic step
- Such an invasive procedure should only be performed after a definitive diagnosis has been established through appropriate imaging
- Cannot be considered without first confirming the diagnosis
*Arteriography*
- **Arteriography** is an invasive procedure used to visualize arteries and diagnose conditions like arterial stenosis or aneurysms
- It is typically reserved for cases where non-invasive imaging (like CT or MRI) has already suggested vascular pathology requiring detailed visualization or intervention planning
- Given the associated risks, it is not indicated as the initial diagnostic step for this presentation
- CT angiography (non-invasive) would be preferred if vascular imaging is needed
*Genetic testing*
- **Genetic testing** is generally reserved for suspected hereditary conditions or when a specific genetic syndrome is being considered
- While the patient has a family history of early MI, this does not indicate genetic testing at this acute evaluation stage
- Not appropriate for the initial workup of persistent cough and abnormal chest imaging
*Esophageal manometry*
- **Esophageal manometry** evaluates esophageal motility and is used to diagnose disorders like achalasia or esophageal spasm
- While esophageal pathology can cause chest discomfort, the presence of an **abnormal chest X-ray** and the patient's significant pulmonary risk factors make pulmonary or cardiovascular causes much more likely
- Esophageal evaluation would not be the priority when chest imaging shows abnormalities requiring further characterization
Question 943: A 35-year-old man comes to the physician because of a rash on the thigh for 10 days. He reports that the rash has been enlarging and is intensely itchy. Two weeks ago, he adopted a stray dog from an animal shelter. Vital signs are within normal limits. A photograph of the examination findings is shown. Which of the following is the most likely cause of this patient's symptoms?
A. Erythrasma
B. Tinea versicolor
C. Pityriasis rosea
D. Psoriasis
E. Dermatophyte infection (Correct Answer)
Explanation: ***Dermatophyte infection***
- The description of an **enlarging, intensely itchy rash** on the thigh, along with recent exposure to a **stray dog**, is highly suggestive of a **dermatophyte (tinea) infection**.
- **Tinea corporis** often presents with **annular (ring-shaped)** lesions with a raised, erythematous, and scaly border, consistent with the typical “ringworm” appearance.
*Erythrasma*
- This is a superficial bacterial infection caused by *Corynebacterium minutissimum*, typically presenting as **reddish-brown patches** with fine scales in intertriginous areas.
- It is usually **asymptomatic or mildly itchy**, unlike the intensely itchy rash described.
*Tinea versicolor*
- Caused by *Malassezia* species, this presents as **hypo- or hyperpigmented macules and patches** with fine scaling, often on the trunk and upper extremities.
- It does not typically form **enlarging, annular lesions** with an active border or cause intense itching to the extent described.
*Pityriasis rosea*
- This is a self-limiting inflammatory rash that typically begins with a **herald patch** followed by smaller, oval, pinkish-red lesions with a fine scale in a "Christmas tree" distribution on the trunk.
- It rarely presents with a single, intensely itchy, enlarging annular lesion on the thigh as the primary complaint.
*Psoriasis*
- Characterized by **well-demarcated, erythematous plaques** covered with silvery scales, commonly affecting extensor surfaces, scalp, and nails.
- Psoriasis lesions are typically **not intensely itchy** in the manner described, nor do they typically present as a rapidly enlarging single annular lesion.
Question 944: A 74-year-old African-American woman is brought to the emergency department by her home health aid. The patient was eating breakfast this morning when she suddenly was unable to lift her spoon with her right hand. She attempted to get up from the table, but her right leg felt weak. One hour later in the emergency department, her strength is 0/5 in the right upper and right lower extremities. Strength is normal in her left upper and lower extremities. Sensation is normal bilaterally. An emergency CT of the head does not show signs of hemorrhage. Subsequent brain MRI shows an infarct involving the internal capsule. Which of the following is true about her disease process?
A. The most common cause is embolism originating from the left atrium
B. IV thrombolysis cannot be used
C. The most important risk factors are ethnicity and sex
D. The most important risk factors are hypertension and diabetes (Correct Answer)
E. It is caused by ischemia to watershed areas
Explanation: ***The most important risk factors are hypertension and diabetes***
- The patient experienced a **lacunar stroke** due to damage to the **internal capsule**, which is typically caused by **small vessel disease**.
- **Hypertension** and **diabetes** are the leading risk factors for **small vessel disease** and subsequent lacunar strokes.
*The most common cause is embolism originating from the left atrium*
- While **cardioembolic strokes** can occur, they more commonly affect larger cerebral arteries and result in cortical deficits, not typically isolated pure motor hemiparesis from internal capsule infarction.
- The sudden onset of symptoms followed by isolated motor weakness without other cortical signs (like aphasia or neglect) makes a lacunar stroke more likely than an embolic stroke from the left atrium.
*IV thrombolysis cannot be used*
- **IV thrombolysis** (e.g., alteplase) can be used for **acute ischemic stroke** if administered within the appropriate time window (typically 4.5 hours from symptom onset) and if there are no contraindications.
- The fact that the patient's symptoms started one hour prior to ED arrival means she would likely be within the window for potential thrombolysis, assuming no contraindications.
*The most important risk factors are ethnicity and sex*
- While race (African-American) and sex (female) can influence stroke risk, **modifiable risk factors** like **hypertension** and **diabetes** are much more significant and directly targetable for prevention and management in this context.
- These demographic factors alone do not explain the pathophysiology of a lacunar stroke.
*It is caused by ischemia to watershed areas*
- **Watershed infarcts** occur in areas supplied by the most distal branches of two major arterial territories, often due to significant **hypoperfusion** (e.g., severe hypotension).
- An infarct in the **internal capsule** suggests a small perforating artery occlusion, characteristic of a lacunar stroke, rather than a watershed infarct.
Question 945: A 68-year-old man is admitted to the intensive care unit after open abdominal aortic aneurysm repair. The patient has received 4 units of packed red blood cells during the surgery. During the first 24 hours following the procedure, he has only passed 200 mL of urine. He has congestive heart failure and hypertension. Current medications include atenolol, enalapril, and spironolactone. He appears ill. His temperature is 37.1°C (98.8°F), pulse is 110/min, respirations are 18/min, and blood pressure is 110/78 mm Hg. Examination shows dry mucous membranes and flat neck veins. The remainder of the examination shows no abnormalities. Laboratory studies show a serum creatinine level of 2.0 mg/dL and a BUN of 48 mg/dL. His serum creatinine and BUN on admission were 1.2 mg/dL and 18 mg/dL, respectively. Further evaluation of this patient is most likely to reveal which of the following findings?
A. Hematuria
B. Low urine sodium (Correct Answer)
C. Leukocyte casts
D. Decreased urine osmolarity
E. Proteinuria
Explanation: ***Low urine sodium***
- The patient's presentation with **oliguria** (200 mL urine in 24 hours), **acute kidney injury** (creatinine rise from 1.2 to 2.0 mg/dL, BUN from 18 to 48 mg/dL), and signs of **hypovolemia** (dry mucous membranes, flat neck veins, tachycardia, borderline hypotension) after major surgery and significant blood loss suggests **prerenal azotemia**.
- In **prerenal azotemia**, the kidneys attempt to conserve sodium and water due to decreased renal perfusion, leading to a **low urine sodium concentration** (typically <20 mEq/L) and a low fractional excretion of sodium (FeNa <1%).
*Hematuria*
- **Hematuria** (blood in urine) is typically associated with intrinsic kidney diseases, urinary tract infections, kidney stones, or trauma, and is not a primary feature of prerenal azotemia.
- While packed red blood cell transfusion occurred, this would not directly cause hematuria in the patient's own urine.
*Leukocyte casts*
- **Leukocyte casts** are indicative of **interstitial nephritis** or **pyelonephritis**, which are intrinsic kidney diseases characterized by inflammation and infection, respectively.
- These findings are not consistent with the clinical picture of prerenal azotemia caused by hypoperfusion.
*Decreased urine osmolarity*
- In **prerenal azotemia**, the kidneys actively reabsorb water to compensate for hypovolemia, resulting in the production of **concentrated urine** with a **high urine osmolality** (typically >500 mOsm/kg).
- **Decreased urine osmolarity** would suggest an inability to concentrate urine, which is seen in conditions like diabetes insipidus or severe intrinsic renal failure, not prerenal azotemia.
*Proteinuria*
- **Proteinuria** is characteristic of **glomerular damage** (e.g., glomerulonephritis) or sometimes tubular dysfunction, which are intrinsic kidney disorders.
- While some minimal proteinuria can occur with any kidney injury, significant proteinuria is not a hallmark of prerenal azotemia caused by hypovolemia.
Question 946: A 15-year-old girl is hospitalized because of increased fatigue and weight loss over the past 2 months. The patient has no personal or family history of a serious illness. She takes no medications, currently. Her blood pressure is 175/74 mm Hg on the left arm and 90/45 on the right. The radial pulse is 84/min but weaker on the right side. The femoral blood pressure and pulses show no abnormalities. Temperature is 38.1℃ (100.6℉). The muscles over the right upper arm are slightly atrophic. The remainder of the examination reveals no abnormalities. Laboratory studies show the following results:
Hemoglobin 10.4 g/dL
Leukocyte count 5,000/mm3
Erythrocyte sedimentation rate 58 mm/h
Magnetic resonance arteriography reveals irregularity, stenosis, and poststenotic dilation involving the proximal right subclavian artery. Prednisone is initiated with improvement of her symptoms. Which of the following is the most appropriate next step in the patient management?
A. Perform angioplasty of subclavian artery stenosis
B. Add cyclophosphamide for severe disease
C. Initiate antihypertensive therapy with ACE inhibitor
D. Monitor ESR and adjust prednisone dosage (Correct Answer)
E. Add methotrexate as steroid-sparing agent
Explanation: ***Monitor ESR and adjust prednisone dosage***
- The patient's presentation with **fatigue, weight loss, differential blood pressures, weak radial pulse**, elevated ESR, and subclavian artery stenosis is highly suggestive of **Takayasu arteritis**.
- **Prednisone is the initial treatment** for Takayasu arteritis, and disease activity is monitored by clinical symptoms and inflammatory markers like **ESR**; thus, monitoring ESR and adjusting the dosage is appropriate.
*Perform angioplasty of subclavian artery stenosis*
- While there is **subclavian artery stenosis**, revascularization procedures like angioplasty are typically considered only **after 2-3 months of medical therapy** has failed to control inflammation and symptoms, or if there is critical ischemia.
- Doing so acutely, while inflammation is still active, carries a **higher risk of restenosis** and complications.
*Add cyclophosphamide for severe disease*
- Cyclophosphamide is a strong immunosuppressant often reserved for **severe, refractory cases** or disease with critical organ involvement, or when patients fail to respond to less aggressive treatments.
- The initial step is to optimize steroid therapy and assess response, as the patient has already shown some improvement with prednisone.
*Initiate antihypertensive therapy with ACE inhibitor*
- The elevated blood pressure is likely a consequence of the underlying **vasculitis affecting renal arteries** or aorta, or differential readings due to subclavian stenosis.
- Addressing the underlying **inflammation with steroids is the primary treatment** for hypertension in Takayasu arteritis; adding antihypertensives might be considered later if hypertension persists despite inflammation control.
*Add methotrexate as steroid-sparing agent*
- **Methotrexate is a steroid-sparing agent** commonly used in Takayasu arteritis, particularly if patients cannot be tapered off steroids or experience significant side effects.
- However, the immediate next step after initiating prednisone and seeing improvement is to **monitor disease activity** and adjust the prednisone dose before adding a second-line agent.
Question 947: A 37-year-old woman accompanied by her husband presents to the emergency department after loss of consciousness 30 minutes ago. The husband reports that she was sitting in a chair at home and began having sustained rhythmic contractions of all 4 extremities for approximately 1 minute. During transport via ambulance she appeared confused but arousable. Her husband reports she has no medical conditions, but for the past 2 months she has occasionally complained of episodes of sweating, palpitations, and anxiety. Her brother has epilepsy and her mother has type 1 diabetes mellitus. Laboratory studies obtained in the emergency department demonstrate the following:
Serum:
Na+: 136 mEq/L
K+: 3.8 mEq/L
Cl-: 100 mEq/L
HCO3-: 19 mEq/L
BUN: 16 mg/dL
Creatinine: 0.9 mg/dL
Glucose: 54 mg/dL
C-peptide: Low
Which of the following is the most likely diagnosis?
A. Beta cell tumor
B. Surreptitious insulin use (Correct Answer)
C. Diabetic ketoacidosis
D. Surreptitious sulfonylurea use
E. Alpha cell tumor
Explanation: ***Surreptitious insulin use***
- The patient presents with **hypoglycemia** (glucose 54 mg/dL) and symptoms consistent with **neuroglycopenia** (loss of consciousness, confusion, sustained rhythmic contractions similar to seizures). The **low C-peptide** in the presence of hypoglycemia strongly indicates exogenous insulin administration, as C-peptide is co-secreted with endogenous insulin.
- The reported past episodes of **sweating, palpitations, and anxiety** are classic symptoms of **adrenergic response to hypoglycemia**, further supporting a diagnosis of recurrent hypoglycemic events.
*Beta cell tumor*
- A beta cell tumor (insulinoma) would also cause **hypoglycemia** (neuroglycopenia) and symptoms like sweating, palpitations, and anxiety.
- However, an insulinoma would typically result in inappropriately **high C-peptide** levels during hypoglycemia, as the tumor produces both insulin and C-peptide endogenously.
*Diabetic ketoacidosis*
- **Diabetic ketoacidosis (DKA)** is characterized by **hyperglycemia**, **ketonemia**, and **metabolic acidosis**, which is the exact opposite of the patient's presentation of hypoglycemia.
- While the patient's mother has type 1 diabetes, this patient does not exhibit any signs of DKA.
*Surreptitious sulfonylurea use*
- Sulfonylurea use would lead to **hypoglycemia** by stimulating insulin release from pancreatic beta cells.
- This would result in **high C-peptide** levels during hypoglycemia, similar to an insulinoma, differentiating it from exogenous insulin use.
*Alpha cell tumor*
- **Alpha cell tumors (glucagonomas)** produce **excess glucagon**, which would lead to **hyperglycemia**, not hypoglycemia.
- Symptoms typically associated with glucagonomas include necrolytic migratory erythema, diabetes, weight loss, and diarrhea, which are not present in this case.
Question 948: A 26-year-old man presents to his primary care physician complaining of impotence. He reports that he has a healthy, long-term relationship with a woman whom he hopes to marry, but he is embarrassed that he is unable to have an erection. Which of the following is the next best step?
A. Obtain a sperm sample
B. Prescribe sildenafil
C. Evaluate nocturnal tumescence (Correct Answer)
D. Duplex penile ultrasound
E. Prescribe vardenafil
Explanation: **Evaluate nocturnal tumescence**
- Evaluating **nocturnal penile tumescence (NPT)** helps differentiate between **organic** and **psychogenic** erectile dysfunction (ED).
- The presence of nocturnal erections indicates **intact physiological mechanisms**, suggesting a **psychogenic cause** of ED rather than a physical one.
*Obtain a sperm sample*
- A sperm sample is collected to assess **male fertility**, which is not the primary complaint or an immediate diagnostic step for erectile dysfunction.
- **Erectile dysfunction** does not necessarily imply infertility, and a sperm sample would not help determine the cause of the inability to achieve an erection.
*Prescribe sildenafil*
- Prescribing a medication like **sildenafil** (a PDE5 inhibitor) without a proper diagnostic workup can mask the underlying cause of ED.
- It is crucial to determine if the ED is **organic or psychogenic** first, as the treatment approach might differ significantly.
*Duplex penile ultrasound*
- A **duplex penile ultrasound** is used to assess **vascular flow** to the penis, but this invasive test is typically reserved for cases where an **organic cause is suspected** after initial evaluations, such as NPT.
- It is not the initial best step, as it provides detailed information about vascular health but doesn't differentiate between organic and psychogenic causes as an initial screening.
*Prescribe vardenafil*
- Similar to sildenafil, **vardenafil** is a PDE5 inhibitor used to treat ED, but it should not be prescribed without first attempting to diagnose the underlying cause.
- Providing symptomatic relief without understanding the etiology can delay appropriate management for potentially serious underlying conditions.
Question 949: A 75-year-old man comes to the physician because of a 4-month history of progressive shortness of breath and chest pressure with exertion. Cardiac examination shows a crescendo-decrescendo systolic murmur that is heard best in the second right intercostal space. Radial pulses are decreased and delayed bilaterally. Transesophageal echocardiography shows hypertrophy of the left ventricle and a thick, calcified aortic valve. The area of the left ventricular outflow tract is 30.6 mm2. Using continuous-wave Doppler measurements, the left ventricular outflow tract velocity is 1.0 m/s, and the peak aortic valve velocity is 3.0 m/s. Which of the following values most closely represents the area of the stenotic aortic valve?
A. 16.0 mm2
B. 23 mm2
C. 10.2 mm2 (Correct Answer)
D. 2.0 mm2
E. 6.2 mm2
Explanation: ***10.2 mm2***
- This value is calculated using the **continuity equation**, which states that the product of the area and velocity at one point in a tube must equal the product of the area and velocity at another point. The formula is: A1 × V1 = A2 × V2, where A1 is the **left ventricular outflow tract (LVOT) area**, V1 is the **LVOT velocity**, A2 is the **aortic valve area (AVA)**, and V2 is the **peak aortic valve velocity**.
- Using the given values: 30.6 mm² × 1.0 m/s = A2 × 3.0 m/s. Solving for A2 gives A2 = (30.6 × 1.0) / 3.0 = **10.2 mm²** (approximately **0.1 cm²**).
- A normal aortic valve area is generally > 2.0 cm² (200 mm²). Severe stenosis is defined as ≤ 1.0 cm² (100 mm²), and this calculated value of 0.1 cm² represents **critical aortic stenosis**, consistent with the patient's symptoms and physical examination findings.
*16.0 mm2*
- This value would be obtained if there was an error in calculation or if one of the velocity or area measurements was significantly different. It does not fit the continuity equation with the given parameters.
- It suggests a higher aortic valve area than calculated, despite the clinical presentation and other measurements pointing towards critical stenosis.
*23 mm2*
- This value is significantly higher than the calculated aortic valve area and would suggest a less severe degree of stenosis than indicated by the patient's symptoms and other findings.
- An error in applying the continuity equation or using incorrect values for velocity or area would lead to this result.
*2.0 mm2*
- This value indicates **extremely severe/critical aortic stenosis** beyond what is calculated. While the patient does have critical stenosis, the continuity equation with the provided data yields 10.2 mm², not 2.0 mm².
- This would imply a much greater velocity ratio or different LVOT measurements than observed.
*6.2 mm2*
- While indicating very severe stenosis, this value is lower than what the continuity equation yields with the given data.
- This result suggests a potential calculation error or misinterpretation of the provided velocities and areas.
Question 950: A 53-year-old woman comes to the physician because of progressive headache and fatigue for the past 2 months. One year ago, she was diagnosed with Cushing disease, which was ultimately treated with bilateral adrenalectomy. Current medications are hydrocortisone and fludrocortisone. Examination shows generalized hyperpigmentation of the skin and bitemporal visual field defects. Serum studies show an ACTH concentration of 1250 pg/mL (N = 20–100). Which of the following is the most appropriate next step in management?
A. Administer metyrapone
B. Administer bromocriptine
C. Reduce dosage of glucocorticoids
D. Resect small cell lung carcinoma
E. Perform radiotherapy of the pituitary (Correct Answer)
Explanation: ***Perform radiotherapy of the pituitary***
- The patient's symptoms (headache, fatigue, **hyperpigmentation**, bitemporal visual field defects), history of bilateral adrenalectomy for Cushing disease, and **very high ACTH level** (1250 pg/mL) are highly characteristic of **Nelson's syndrome**. This syndrome results from the unchecked growth of a pituitary adenoma after the removal of the adrenal glands, leading to an overproduction of ACTH.
- **Radiotherapy of the pituitary** is a primary treatment for Nelson's syndrome, aiming to shrink the pituitary adenoma and reduce ACTH secretion, thereby alleviating symptoms and preventing further tumor growth or mass effect on the optic chiasm.
*Administer metyrapone*
- **Metyrapone** inhibits **11β-hydroxylase**, blocking cortisol synthesis in the adrenal glands. It is used to treat hypercortisolism (Cushing's syndrome) but is not appropriate here as the patient has undergone bilateral adrenalectomy and is already on replacement therapy.
- This patient is experiencing a sequela of her adrenalectomy (Nelson's syndrome) characterized by ACTH overproduction, not excess cortisol.
*Administer bromocriptine*
- **Bromocriptine** is a **dopamine agonist** primarily used to treat **prolactinomas**. While some pituitary tumors may respond to dopamine agonists, it is not the standard or most effective treatment for ACTH-secreting pituitary adenomas causing Nelson's syndrome.
- The clinical presentation points towards an ACTH-producing adenoma, not a prolactinoma, making bromocriptine an inappropriate first-line treatment.
*Reduce dosage of glucocorticoids*
- The patient is taking hydrocortisone and fludrocortisone as **adrenal hormone replacement therapy** after bilateral adrenalectomy. Reducing this dosage would lead to **adrenal insufficiency**, which could be life-threatening.
- The current problem is excessive ACTH from a growing pituitary tumor, not iatrogenic hypercortisolism from replacement therapy.
*Resect small cell lung carcinoma*
- While **small cell lung carcinoma** can cause **ectopic ACTH syndrome**, leading to hyperpigmentation and elevated ACTH, the patient's history of **Cushing disease treated with bilateral adrenalectomy** and the development of bitemporal hemianopsia strongly point to a pituitary-derived issue (Nelson's syndrome).
- The bitemporal visual field defect is a classic sign of a **pituitary mass compressing the optic chiasm**, which is inconsistent with an ectopic source of ACTH.
