A 67-year-old man comes to the office due to pain in the lower part of his calves on his afternoon walk to get the mail. The pain is relieved by rest. It started slowly about 6 months ago and has become more painful over time. He has a history of hypertension, hyperlipidemia, diabetes mellitus, and a 20-pack-year smoking history. Medications include hydrochlorothiazide, atorvastatin, metformin, and a multivitamin that he takes daily. The patient quit smoking 2 years ago and only drinks socially. Today, his blood pressure is 145/90 mm Hg, pulse is 75/min, respiratory rate is 17/min, and temperature is 37.6°C (99.6°F). On physical exam, he appears mildly obese and healthy. His heart has a regular rate and rhythm, and his lungs are clear to auscultation bilaterally. Examination of the legs shows atrophic changes and diminished pedal pulses. A measure of his ankle brachial index (ABI) is 0.89. Which of the following is the most appropriate initial treatment?
Q1172
A 51-year-old female presents to her primary care physician complaining of body aches and constipation. She reports that her "bones hurt" and that she has experienced worsening constipation over the past few months. Her medical history is notable for three kidney stones within the past year that both passed spontaneously. Her vital signs are stable. Physical examination reveals a small nodule near the right inferior pole of the thyroid, consistent with a parathyroid adenoma. Which of the following sets of serum findings is most likely in this patient?
Q1173
An 81-year-old woman comes to the emergency department due to a left-sided paralysis for the past 2 hours. Her husband says her symptoms began suddenly, and she is also unable to speak. Her pulse is 90/min, respirations are 18/min, temperature is 36.8°C (98.2°F), and blood pressure is 150/98 mm Hg. An ECG is obtained and is shown below. Which of the following is the most probable cause of the patient's paralysis?
Q1174
A 42-year-old woman comes to the physician because of a 12 month history of progressive fatigue and shortness of breath with exertion. Five years ago, she emigrated from Eastern Europe. She has smoked one pack of cigarettes daily for 20 years. She has a history of using methamphetamines and cocaine but quit 5 years ago. Vital signs are within normal limits. Physical examination shows jugular venous pulsations 9 cm above the sternal angle. The lungs are clear to auscultation. There is a normal S1 and a loud, split S2. An impulse can be felt with the fingers left of the sternum. The abdomen is soft and nontender. The fingertips are enlarged and the nails are curved. There is pitting edema around the ankles bilaterally. An x-ray of the chest shows pronounced central pulmonary arteries and a prominent right heart border. Which of the following is most likely to confirm the diagnosis?
Q1175
A 29-year-old woman is brought to the emergency department after an episode of syncope. For the past 10 days, she has had dyspnea and palpitations occurring with mild exertion. The patient returned from a hiking trip in Upstate New York 5 weeks ago. Except for an episode of flu with fever and chills a month ago, she has no history of serious illness. Her temperature is 37.3°C (99.1°F), pulse is 45/min, respirations are 21/min, and blood pressure is 148/72 mm Hg. A resting ECG is shown. Two-step serological testing confirms the diagnosis. Which of the following is the most appropriate treatment?
Q1176
A 73-year-old man is brought in by his wife with a history of progressive personality changes. The patient’s wife says that, over the past 3 years, he has become increasingly aggressive and easily agitated, which is extremely out of character for him. His wife also says that he has had several episodes of urinary incontinence in the past month. He has no significant past medical history. The patient denies any history of smoking, alcohol use, or recreational drug use. The patient is afebrile, and his vital signs are within normal limits. A physical examination is unremarkable. The patient takes the mini-mental status examination (MMSE) and scores 28/30. A T2 magnetic resonance image (MRI) of the head is performed and the results are shown in the exhibit (see image). Which of the following is the next best diagnostic step in the management of this patient?
Q1177
A 57-year-old man presents to his physician with dyspnea on exertion and rapid heartbeat. He denies any pain during these episodes. He works as a machine operator at a solar panels manufacturer. He has a 21-pack-year history of smoking. The medical history is significant for a perforated ulcer, in which he had to undergo gastric resection and bypass. He also has a history of depression, and he is currently taking escitalopram. The family history is unremarkable. The patient weighs 69 kg (152 lb). His height is 169 cm (5 ft 7 in). The vital signs include: blood pressure 140/90 mm Hg, heart rate 95/min, respiratory rate 12/min, and temperature 36.6℃ (97.9℉). Lung auscultation reveals widespread wheezes. Cardiac auscultation shows decreased S1 and grade 1/6 midsystolic murmur best heard at the apex. Abdominal and neurological examinations show no abnormalities. A subsequent echocardiogram shows increased left ventricular mass and an ejection fraction of 50%. Which of the options is a risk factor for the condition detected in the patient?
Q1178
A 71-year-old male presents to the emergency department after having a generalized tonic-clonic seizure. His son reports that he does not have a history of seizures but has had increasing confusion and weakness over the last several weeks. An electrolyte panel reveals a sodium level of 120 mEq/L and a serum osmolality of 248 mOsm/kg. His urine is found to have a high urine osmolality. His temperature is 37° C (98.6° F), respirations are 15/min, pulse is 67/min, and blood pressure is 122/88 mm Hg. On examination he is disoriented, his pupils are round and reactive to light and accommodation and his mucous membranes are moist. His heart has a regular rhythm without murmurs, his lungs are clear to auscultation bilaterally, the abdomen is soft, and his extremities have no edema but his muscular strength is 3/5 bilaterally. There is hyporeflexia of all four extremities. What is the most likely cause of his symptoms?
Q1179
A 71-year-old African American man is brought to the emergency department with sudden onset lower limb paralysis and back pain. He has had generalized bone pain for 2 months. He has no history of severe illnesses. He takes ibuprofen for pain. On examination, he is pale. The vital signs include: temperature 37.1°C (98.8°F), pulse 68/min, respiratory rate 16/min, and blood pressure 155/90 mm Hg. The neurologic examination shows paraparesis. The 8th thoracic vertebra is tender to palpation. X-ray of the thoracic vertebrae confirms a compression fracture at the same level. The laboratory studies show the following:
Laboratory test
Hemoglobin 9 g/dL
Mean corpuscular volume 95 μm3
Leukocyte count 5,000/mm3
Platelet count 240,000/mm3
ESR 85 mm/hr
Serum
Na+ 135 mEq/L
K+ 4.2 mEq/L
Cl− 113 mEq/L
HCO3− 20 mEq/L
Ca+ 11.8 mg/dL
Albumin 4 g/dL
Urea nitrogen 38 mg/dL
Creatinine 2.2 mg/dL
Which of the following is the most likely mechanism underlying this patient’s vertebral fracture?
Q1180
A 48-year-old man with a 30-pack-year history comes to the physician for a follow-up examination 6 months after a chest CT showed a solitary 5-mm solid nodule in the upper lobe of the right lung. The follow-up CT shows that the size of the nodule has increased to 2 cm. Ipsilateral mediastinal lymph node involvement is noted. A biopsy of the pulmonary nodule shows small, dark blue tumor cells with hyperchromatic nuclei and scarce cytoplasm. Cranial MRI and skeletal scintigraphy show no evidence of other metastases. Which of the following is the most appropriate next step in management?
Cardiology US Medical PG Practice Questions and MCQs
Question 1171: A 67-year-old man comes to the office due to pain in the lower part of his calves on his afternoon walk to get the mail. The pain is relieved by rest. It started slowly about 6 months ago and has become more painful over time. He has a history of hypertension, hyperlipidemia, diabetes mellitus, and a 20-pack-year smoking history. Medications include hydrochlorothiazide, atorvastatin, metformin, and a multivitamin that he takes daily. The patient quit smoking 2 years ago and only drinks socially. Today, his blood pressure is 145/90 mm Hg, pulse is 75/min, respiratory rate is 17/min, and temperature is 37.6°C (99.6°F). On physical exam, he appears mildly obese and healthy. His heart has a regular rate and rhythm, and his lungs are clear to auscultation bilaterally. Examination of the legs shows atrophic changes and diminished pedal pulses. A measure of his ankle brachial index (ABI) is 0.89. Which of the following is the most appropriate initial treatment?
A. A recommendation to walk more
B. Metoprolol
C. A recommendation to perform pedal pumping exercises
D. A referral to a supervised exercise program (Correct Answer)
E. Enoxaparin
Explanation: ***A referral to a supervised exercise program***
- The patient's symptoms (claudication, relief with rest), risk factors (**hypertension, hyperlipidemia, diabetes, smoking history**), physical exam findings (**atrophic changes, diminished pedal pulses**), and **ABI of 0.89** (indicating mild peripheral artery disease) all point to **peripheral arterial disease (PAD)**.
- A **supervised exercise program**, particularly walking, is the most effective initial non-pharmacological treatment for improving walking distance and quality of life in patients with claudication due to PAD.
*A recommendation to walk more*
- While walking is beneficial, simply recommending "walking more" without specific guidance or supervision is less effective than a structured program.
- An unsupervised general walking recommendation may not optimize the **duration**, **intensity**, or **frequency** needed for therapeutic benefit in PAD.
*Metoprolol*
- **Beta-blockers** like metoprolol can worsen claudication symptoms by decreasing blood flow to the extremities, especially in patients with PAD.
- They are generally **contraindicated** or used with caution in PAD patients experiencing claudication.
*A recommendation to perform pedal pumping exercises*
- **Pedal pumping exercises** are primarily used to prevent **venous stasis** and **deep vein thrombosis**, typically post-surgery or during prolonged immobility.
- They do not address the underlying arterial insufficiency causing claudication and are not an effective treatment for PAD.
*Enoxaparin*
- **Enoxaparin** is a low molecular weight heparin, an **anticoagulant** used for conditions like deep vein thrombosis or acute coronary syndromes.
- It is not indicated for the chronic management of stable claudication in peripheral artery disease, where antiplatelet therapy is generally preferred if medication is needed.
Question 1172: A 51-year-old female presents to her primary care physician complaining of body aches and constipation. She reports that her "bones hurt" and that she has experienced worsening constipation over the past few months. Her medical history is notable for three kidney stones within the past year that both passed spontaneously. Her vital signs are stable. Physical examination reveals a small nodule near the right inferior pole of the thyroid, consistent with a parathyroid adenoma. Which of the following sets of serum findings is most likely in this patient?
A. Increased calcium, decreased phosphate, increased parathyroid hormone (Correct Answer)
B. Decreased calcium, increased phosphate, decreased parathyroid hormone
C. Normal calcium, normal phosphate, normal parathyroid hormone
D. Decreased calcium, increased phosphate, increased parathyroid hormone
E. Increased calcium, decreased phosphate, decreased parathyroid hormone
Explanation: ***Increased calcium, decreased phosphate, increased parathyroid hormone***
- This patient's symptoms, including "bones hurt" (bone pain), constipation, and a history of kidney stones (kidney groans), are classic manifestations of **hyperparathyroidism**, often associated with a parathyroid adenoma (nodule near the thyroid).
- Primary hyperparathyroidism is characterized by inappropriately high **PTH levels** leading to increased calcium reabsorption from bone and kidneys, resulting in **hypercalcemia**, and increased phosphate excretion, leading to **hypophosphatemia**.
*Decreased calcium, increased phosphate, decreased parathyroid hormone*
- This profile suggests **hypoparathyroidism**, where reduced PTH leads to decreased calcium mobilization and renal phosphate clearance.
- This scenario would not explain the patient's symptoms of bone pain, constipation, or kidney stones, which are related to elevated calcium.
*Normal calcium, normal phosphate, normal parathyroid hormone*
- This indicates **normal parathyroid function** and calcium homeostasis, which contradicts the presented symptoms pointing towards a significant metabolic disturbance.
- The patient's clinical presentation strongly suggests an endocrine disorder affecting calcium regulation.
*Decreased calcium, increased phosphate, increased parathyroid hormone*
- This set of findings is characteristic of **secondary hyperparathyroidism**, often seen in chronic kidney disease where low calcium (due to impaired vitamin D activation) stimulates PTH release.
- However, the patient's presentation with hypercalcemia-related symptoms like bone pain and kidney stones, along with a discrete parathyroid nodule, points more towards primary hyperparathyroidism.
*Increased calcium, decreased phosphate, decreased parathyroid hormone*
- This profile, with **hypercalcemia** and **low PTH**, is typical of **humoral hypercalcemia of malignancy** or vitamin D toxicity, where an external source of calcium raises levels without PTH involvement.
- However, the presence of a palpable parathyroid nodule and the specific constellation of "stones, bones, groans" are highly indicative of primary hyperparathyroidism, which involves increased PTH.
Question 1173: An 81-year-old woman comes to the emergency department due to a left-sided paralysis for the past 2 hours. Her husband says her symptoms began suddenly, and she is also unable to speak. Her pulse is 90/min, respirations are 18/min, temperature is 36.8°C (98.2°F), and blood pressure is 150/98 mm Hg. An ECG is obtained and is shown below. Which of the following is the most probable cause of the patient's paralysis?
A. Cocaine toxicity
B. Rupture of berry aneurysm
C. Hemorrhagic disorder
D. Cardioembolic stroke (Correct Answer)
E. Conversion disorder
Explanation: ***Cardioembolic stroke***
- The patient presents with **acute neurological deficits** (left-sided paralysis, aphasia) suggesting a **stroke**. The ECG shows **atrial fibrillation** (irregularly irregular rhythm with no clear P waves), which is a significant risk factor for cardioembolic stroke due to thrombus formation in the left atrium.
- The **sudden onset of symptoms** is highly characteristic of an ischemic stroke, and the presence of atrial fibrillation makes a cardioembolic source very likely.
*Cocaine toxicity*
- While cocaine can cause stroke due to vasospasm or accelerated atherosclerosis, it is **less probable in an 81-year-old woman** without other indicators of drug abuse.
- The symptoms of cocaine toxicity usually include **agitation, tachycardia, hypertension, and dilated pupils**, which are not consistently described here.
*Rupture of berry aneurysm*
- A ruptured berry aneurysm typically causes a **subarachnoid hemorrhage**, presenting with a **sudden, severe headache** ("thunderclap headache"), meningismus, and often altered consciousness.
- While it can cause focal neurological deficits, the primary presentation is usually different, and the ECG finding of atrial fibrillation does not directly support this diagnosis.
*Hemorrhagic disorder*
- While a hemorrhagic stroke could present with similar neurological deficits, a **primary hemorrhagic disorder** would typically involve a broader history of easy bruising or bleeding, which is not mentioned.
- The ECG finding of **atrial fibrillation** points more strongly towards an embolic rather than hemorrhagic etiology in this context.
*Conversion disorder*
- Conversion disorder is a **functional neurological symptom disorder** where psychological stressors manifest as neurological symptoms without an organic cause.
- The patient's age (81), acute onset of severe, distinct neurological deficits, and especially the **objective finding of atrial fibrillation** on ECG, make a psychological explanation highly unlikely when a clear organic cause is suggested.
Question 1174: A 42-year-old woman comes to the physician because of a 12 month history of progressive fatigue and shortness of breath with exertion. Five years ago, she emigrated from Eastern Europe. She has smoked one pack of cigarettes daily for 20 years. She has a history of using methamphetamines and cocaine but quit 5 years ago. Vital signs are within normal limits. Physical examination shows jugular venous pulsations 9 cm above the sternal angle. The lungs are clear to auscultation. There is a normal S1 and a loud, split S2. An impulse can be felt with the fingers left of the sternum. The abdomen is soft and nontender. The fingertips are enlarged and the nails are curved. There is pitting edema around the ankles bilaterally. An x-ray of the chest shows pronounced central pulmonary arteries and a prominent right heart border. Which of the following is most likely to confirm the diagnosis?
A. CT angiography
B. Serologic testing
C. Doppler echocardiography
D. High-resolution CT of the lung
E. Right-heart catheterization (Correct Answer)
Explanation: ***Right-heart catheterization***
- This is the **gold standard** for diagnosing **pulmonary hypertension** by directly measuring pulmonary artery pressure, pulmonary wedge pressure, and cardiac output. The patient's symptoms (fatigue, shortness of breath, loud split S2, prominent right heart border, JVP elevation, peripheral edema, digital clubbing) strongly suggest pulmonary hypertension.
- It helps classify the type of pulmonary hypertension and guides treatment strategies, as **mean pulmonary artery pressure (mPAP) > 20 mmHg** at rest is diagnostic.
*CT angiography*
- Primarily used to diagnose **pulmonary embolism** or to evaluate for chronic thromboembolic pulmonary hypertension (CTEPH). While helpful in some cases of pulmonary hypertension, it does not directly measure pressures.
- It would show emboli or chronic organized thrombi if present but doesn't provide the hemodynamic data needed to confirm the severity and type of pulmonary hypertension.
*Serologic testing*
- Used to identify underlying systemic diseases (e.g., **autoimmune conditions like scleroderma**) that can cause pulmonary hypertension. However, it does not directly confirm the diagnosis of pulmonary hypertension itself.
- While it may uncover **etiological factors**, serological markers are not diagnostic for the presence or severity of pulmonary hypertension.
*Doppler echocardiography*
- A crucial initial screening tool that **estimates pulmonary artery pressure** and assesses right ventricular function, often prompting further investigation for pulmonary hypertension.
- While highly suggestive, it is **indirect and an estimation**, and thus not considered definitive for confirming the diagnosis or for precise hemodynamic measurements.
*High-resolution CT of the lung*
- Used to evaluate for **interstitial lung disease** or other parenchymal lung conditions that can cause secondary pulmonary hypertension.
- It provides detailed images of the lung parenchyma but does not directly measure pulmonary pressures or confirm the diagnosis of pulmonary hypertension.
Question 1175: A 29-year-old woman is brought to the emergency department after an episode of syncope. For the past 10 days, she has had dyspnea and palpitations occurring with mild exertion. The patient returned from a hiking trip in Upstate New York 5 weeks ago. Except for an episode of flu with fever and chills a month ago, she has no history of serious illness. Her temperature is 37.3°C (99.1°F), pulse is 45/min, respirations are 21/min, and blood pressure is 148/72 mm Hg. A resting ECG is shown. Two-step serological testing confirms the diagnosis. Which of the following is the most appropriate treatment?
A. Intravenous ceftriaxone (Correct Answer)
B. Atropine
C. Oral doxycycline
D. Beta blocker
E. Permanent pacemaker implantation
Explanation: ***Intravenous ceftriaxone***
- The patient's symptoms (syncope, dyspnea, palpitations, travel history to Upstate New York, prior flu-like illness) and **bradycardia (pulse 45/min)** with the ECG findings strongly suggest **Stage II Lyme carditis** (AV block).
- **Intravenous ceftriaxone** is the recommended treatment for **severe Lyme disease manifestations**, including **Lyme carditis with high-grade AV block**, due to its excellent penetration and efficacy against *Borrelia burgdorferi*.
*Atropine*
- Atropine is used for **acute symptomatic bradycardia** to temporarily increase heart rate but does not treat the underlying cause of Lyme carditis.
- Its effect is **transient**, and it's not a definitive therapy for persistent bradycardia due to infection.
*Oral doxycycline*
- **Oral doxycycline** is appropriate for **early-stage Lyme disease** (e.g., erythema migrans, mild facial palsy) or **mild Lyme carditis** without high-grade AV block.
- Given the **high-grade AV block** (implied by bradycardia and syncope) and the need for prompt management of severe manifestations, intravenous therapy is preferred.
*Beta blocker*
- Beta blockers **slow the heart rate** and are contraindicated in patients with **symptomatic bradycardia** or **high-grade AV block**.
- Administering a beta blocker would worsen the patient's condition by exacerbating the existing bradycardia.
*Permanent pacemaker implantation*
- While a **temporary pacemaker** might be considered for **life-threatening bradycardia** not responding to medical therapy in Lyme carditis, **permanent pacemaker implantation** is typically reserved for **irreversible, persistent AV block**.
- In Lyme carditis, the AV block **often resolves with appropriate antibiotic treatment**, making a permanent pacemaker unnecessary in most cases.
Question 1176: A 73-year-old man is brought in by his wife with a history of progressive personality changes. The patient’s wife says that, over the past 3 years, he has become increasingly aggressive and easily agitated, which is extremely out of character for him. His wife also says that he has had several episodes of urinary incontinence in the past month. He has no significant past medical history. The patient denies any history of smoking, alcohol use, or recreational drug use. The patient is afebrile, and his vital signs are within normal limits. A physical examination is unremarkable. The patient takes the mini-mental status examination (MMSE) and scores 28/30. A T2 magnetic resonance image (MRI) of the head is performed and the results are shown in the exhibit (see image). Which of the following is the next best diagnostic step in the management of this patient?
A. Contrast MRI of the head
B. Lumbar puncture (Correct Answer)
C. Noncontrast CT of the head
D. Brain biopsy
E. Serum ceruloplasmin level
Explanation: ***Lumbar puncture***
- The MRI shows **ventriculomegaly** with **transependymal CSF flow**, indicating **normal pressure hydrocephalus (NPH)**. A high-volume lumbar puncture serves as both a diagnostic and therapeutic test for NPH, as improvement in symptoms after CSF removal (typically 30-50 mL) strongly supports the diagnosis.
- This patient presents with **progressive cognitive decline** (personality changes, aggression, agitation) and **urinary incontinence**, two components of the classic NPH triad. While gait disturbance is the third component and most common presenting feature, NPH can present with incomplete triads, and the imaging findings strongly support this diagnosis.
*Contrast MRI of the head*
- Contrast-enhanced MRI is used to visualize specific lesions such as **tumors, infections, or inflammatory processes**, which are not suggested by this patient's presentation.
- The T2 MRI has already demonstrated findings consistent with NPH (ventriculomegaly with transependymal flow), making additional contrast imaging unnecessary for diagnosis at this stage.
*Noncontrast CT of the head*
- While noncontrast CT can demonstrate ventriculomegaly, **MRI provides superior resolution** for evaluating brain parenchyma and detecting **transependymal CSF flow**, a key indicator of NPH.
- Since MRI has already been performed and revealed findings diagnostic of NPH, repeating imaging with a less detailed modality would not add diagnostic value.
*Brain biopsy*
- Brain biopsy is an **invasive procedure** reserved for cases where **neoplastic, infectious, or demyelinating** conditions are strongly suspected and cannot be diagnosed by less invasive means.
- There is no indication of a mass lesion, infection, or focal abnormality requiring tissue diagnosis in this patient's clinical presentation or imaging findings.
*Serum ceruloplasmin level*
- Serum ceruloplasmin is used to diagnose **Wilson's disease**, a rare genetic disorder of copper metabolism presenting with neuropsychiatric symptoms and movement disorders, typically in patients **under 40 years of age**.
- Given this patient's age (73 years) and clear radiological evidence of NPH, Wilson's disease is not a consideration in the differential diagnosis.
Question 1177: A 57-year-old man presents to his physician with dyspnea on exertion and rapid heartbeat. He denies any pain during these episodes. He works as a machine operator at a solar panels manufacturer. He has a 21-pack-year history of smoking. The medical history is significant for a perforated ulcer, in which he had to undergo gastric resection and bypass. He also has a history of depression, and he is currently taking escitalopram. The family history is unremarkable. The patient weighs 69 kg (152 lb). His height is 169 cm (5 ft 7 in). The vital signs include: blood pressure 140/90 mm Hg, heart rate 95/min, respiratory rate 12/min, and temperature 36.6℃ (97.9℉). Lung auscultation reveals widespread wheezes. Cardiac auscultation shows decreased S1 and grade 1/6 midsystolic murmur best heard at the apex. Abdominal and neurological examinations show no abnormalities. A subsequent echocardiogram shows increased left ventricular mass and an ejection fraction of 50%. Which of the options is a risk factor for the condition detected in the patient?
A. History of gastric bypass surgery
B. Exposure to heavy metals
C. Escitalopram intake
D. The patient’s body mass
E. Smoking (Correct Answer)
Explanation: ***Smoking***
- The patient's 21-pack-year smoking history is a significant risk factor for **hypertension** and **cardiovascular disease**, contributing to increased left ventricular mass and cardiac dysfunction.
- Smoking directly damages blood vessels and the heart, leading to increased afterload and subsequent **left ventricular hypertrophy** (LVH), as seen on this patient's echocardiogram.
*History of gastric bypass surgery*
- While gastric bypass surgery is associated with malabsorption and nutritional deficiencies (including thiamine deficiency leading to wet beriberi), it is not a direct risk factor for **hypertensive heart disease** with LVH.
- The patient's elevated blood pressure (140/90 mm Hg) and smoking history are more directly responsible for the cardiac findings.
*Exposure to heavy metals*
- Exposure to certain heavy metals (e.g., lead, cadmium) can be associated with cardiovascular disease, but the patient's job as a machine operator at a solar panel manufacturer does not inherently imply significant exposure to these specific toxins.
- The presenting symptoms and echocardiogram findings are more directly attributable to **hypertension** and **smoking**, which are clearly documented risk factors in this patient.
*Escitalopram intake*
- Escitalopram is an SSRI antidepressant with a generally low cardiotoxicity profile; it is not associated with **left ventricular hypertrophy** or the development of structural heart disease.
- While some medications can affect cardiac function, escitalopram is not a primary risk factor for the observed changes.
*The patient's body mass*
- The patient's BMI can be calculated as 69 kg / (1.69 m)² ≈ 24.1 kg/m², which falls within the **normal weight range** (18.5-24.9 kg/m²).
- Therefore, obesity and its associated cardiac risks (which can contribute to hypertension and LVH) are not applicable to this patient's presentation.
Question 1178: A 71-year-old male presents to the emergency department after having a generalized tonic-clonic seizure. His son reports that he does not have a history of seizures but has had increasing confusion and weakness over the last several weeks. An electrolyte panel reveals a sodium level of 120 mEq/L and a serum osmolality of 248 mOsm/kg. His urine is found to have a high urine osmolality. His temperature is 37° C (98.6° F), respirations are 15/min, pulse is 67/min, and blood pressure is 122/88 mm Hg. On examination he is disoriented, his pupils are round and reactive to light and accommodation and his mucous membranes are moist. His heart has a regular rhythm without murmurs, his lungs are clear to auscultation bilaterally, the abdomen is soft, and his extremities have no edema but his muscular strength is 3/5 bilaterally. There is hyporeflexia of all four extremities. What is the most likely cause of his symptoms?
A. Hereditary diabetes insipidus
B. Sheehan’s syndrome
C. Syndrome of Inappropriate Antidiuretic Hormone (SIADH) (Correct Answer)
D. Diabetic ketoacidosis
E. Lithium use
Explanation: ***Syndrome of Inappropriate Antidiuretic Hormone (SIADH)***
- This patient presents with **hypotonic hyponatremia** (serum Na 120 mEq/L, osmolality 248 mOsm/kg) in the setting of a **high urine osmolality**, indicating the kidney is inappropriately concentrating urine despite low plasma osmolality.
- The symptoms of **confusion, weakness, generalized tonic-clonic seizure**, and **hyporeflexia** are consistent with severe hyponatremia affecting neurological function.
*Hereditary diabetes insipidus*
- This condition is characterized by the inability to concentrate urine, leading to **polyuria** and **polydipsia**, and often hypernatremia, which is the opposite of this patient's presentation.
- Patients typically have **low urine osmolality** and high serum osmolality due to excessive water loss.
*Sheehan's syndrome*
- This syndrome is a cause of **hypopituitarism** due to postpartum hemorrhage, leading to deficiencies in various pituitary hormones, including ADH if the posterior pituitary is affected.
- ADH deficiency would lead to **diabetes insipidus-like symptoms** (high serum osmolality, low urine osmolality, polyuria) and not the hyponatremia seen in this patient unless there's profound adrenal insufficiency (cortisol deficiency), but the primary lab findings contradict ADH excess.
*Diabetic ketoacidosis*
- This condition is characterized by **hyperglycemia**, metabolic acidosis, and ketonemia, often leading to polyuria and polydipsia, and can cause **hypernatremia** or pseudohyponatremia.
- The patient's blood pressure, heart rate, and lack of symptoms like Kussmaul respirations or fruity breath do not support DKA, and his sodium is low, not high.
*Lithium use*
- Chronic lithium use can cause **nephrogenic diabetes insipidus** by interfering with ADH action in the renal tubules, leading to an inability to concentrate urine.
- This would result in **polyuria, polydipsia**, and potentially hypernatremia and low urine osmolality, which is inconsistent with the patient's findings of hyponatremia and high urine osmolality.
Question 1179: A 71-year-old African American man is brought to the emergency department with sudden onset lower limb paralysis and back pain. He has had generalized bone pain for 2 months. He has no history of severe illnesses. He takes ibuprofen for pain. On examination, he is pale. The vital signs include: temperature 37.1°C (98.8°F), pulse 68/min, respiratory rate 16/min, and blood pressure 155/90 mm Hg. The neurologic examination shows paraparesis. The 8th thoracic vertebra is tender to palpation. X-ray of the thoracic vertebrae confirms a compression fracture at the same level. The laboratory studies show the following:
Laboratory test
Hemoglobin 9 g/dL
Mean corpuscular volume 95 μm3
Leukocyte count 5,000/mm3
Platelet count 240,000/mm3
ESR 85 mm/hr
Serum
Na+ 135 mEq/L
K+ 4.2 mEq/L
Cl− 113 mEq/L
HCO3− 20 mEq/L
Ca+ 11.8 mg/dL
Albumin 4 g/dL
Urea nitrogen 38 mg/dL
Creatinine 2.2 mg/dL
Which of the following is the most likely mechanism underlying this patient’s vertebral fracture?
A. Increased mechanical pressure
B. Proliferation of tumor cells (Correct Answer)
C. Bone demineralization
D. Increased osteoblastic activity
E. Acidosis-induced bone lysis
Explanation: ***Proliferation of tumor cells***
- The patient's presentation with **bone pain**, **hypercalcemia** (11.8 mg/dL), **anemia** (Hb 9 g/dL), **elevated ESR** (85 mm/hr), and **vertebral compression fracture** is highly suggestive of **multiple myeloma**.
- **Multiple myeloma** is characterized by the proliferation of malignant plasma cells in the bone marrow, which leads to bone destruction through **osteoclast activation** and inhibition of osteoblasts, making the bone susceptible to **pathological fractures**.
*Increased mechanical pressure*
- While mechanical pressure can contribute to fractures, it is typically seen in the context of trauma or repetitive stress on already weakened bone.
- The clinical picture of systemic symptoms like **anemia, hypercalcemia**, and **elevated ESR** points to an underlying pathological process rather than solely mechanical forces.
*Bone demineralization*
- **Bone demineralization** can occur due to various conditions like osteoporosis or vitamin D deficiency, leading to weaker bones.
- However, the patient's specific constellation of symptoms, including **paraparesis, hypercalcemia**, and a **compression fracture** in an older adult, points more directly toward a plasma cell dyscrasia rather than simple demineralization.
*Increased osteoblastic activity*
- Increased osteoblastic activity leads to **bone formation**, which would strengthen bones rather than predispose them to compression fractures.
- Conditions with increased osteoblastic activity, such as Paget's disease, would typically present with different clinical and laboratory findings.
*Acidosis-induced bone lysis*
- **Chronic metabolic acidosis** can lead to bone demineralization and bone lysis over time, as the bone buffers the excess acid.
- However, the patient's **bicarbonate level is 20 mEq/L**, which indicates a mild metabolic acidosis that is unlikely to be the primary cause of such severe, acute bone lysis and compression fracture in this context, especially with other strong indicators of **multiple myeloma**.
Question 1180: A 48-year-old man with a 30-pack-year history comes to the physician for a follow-up examination 6 months after a chest CT showed a solitary 5-mm solid nodule in the upper lobe of the right lung. The follow-up CT shows that the size of the nodule has increased to 2 cm. Ipsilateral mediastinal lymph node involvement is noted. A biopsy of the pulmonary nodule shows small, dark blue tumor cells with hyperchromatic nuclei and scarce cytoplasm. Cranial MRI and skeletal scintigraphy show no evidence of other metastases. Which of the following is the most appropriate next step in management?
A. Cisplatin-etoposide therapy and radiotherapy (Correct Answer)
B. Gefitinib therapy
C. Wedge resection
D. Radiation therapy
E. Right lobectomy
Explanation: ***Cisplatin-etoposide therapy and radiotherapy***
- The biopsy findings of **small, dark blue cells with hyperchromatic nuclei** are classic for **small cell lung cancer (SCLC)**. The rapid growth of the nodule and **ipsilateral mediastinal lymph node involvement** indicate locally advanced disease, which is best treated with combined **chemotherapy (cisplatin-etoposide)** and **radiotherapy**.
- SCLC is highly aggressive and metastasizes early, rendering surgery typically ineffective for curative intent in this stage. Combined modality therapy improves survival in patients with limited-stage SCLC.
*Gefitinib therapy*
- **Gefitinib** is an **EGFR tyrosine kinase inhibitor** used for **non-small cell lung cancer (NSCLC)** that harbors specific sensitizing **EGFR mutations**.
- It is not indicated for SCLC, as this type of cancer typically lacks these mutations and responds poorly to EGFR inhibitors.
*Wedge resection*
- **Wedge resection** is a surgical procedure typically reserved for **early-stage, peripheral NSCLC** or benign nodules.
- Given the diagnosis of SCLC with mediastinal lymph node involvement, **surgical resection is generally not curative** and would be an inadequate treatment.
*Radiation therapy*
- While radiation therapy is a crucial component in SCLC treatment, particularly for **local control**, it is **insufficient as a monotherapy** for limited-stage SCLC.
- **Systemic chemotherapy** is essential to address potential micrometastases and is always combined with radiation for this stage of SCLC.
*Right lobectomy*
- A **lobectomy** is a surgical procedure to remove an entire lobe of the lung, usually considered for **resectable NSCLC** without significant nodal involvement.
- For SCLC with **mediastinal lymph node involvement**, a lobectomy alone is highly unlikely to be curative, and **combined chemoradiotherapy** is the standard primary treatment.