A 22-year-old woman is brought to the emergency department after being struck by a car while crossing the street. She has major depressive disorder with psychosis. Current medications include sertraline and haloperidol. Vital signs are within normal limits. X-ray of the lower extremity shows a mid-shaft femur fracture. The patient is taken to the operating room for surgical repair of the fracture. As the surgeon begins the internal fixation, the patient shows muscle rigidity and profuse diaphoresis. Her temperature is 39°C (102.2°F), pulse is 130/min, respirations are 24/min, and blood pressure is 146/70 mm Hg. The pupils are equal and reactive to light. The end tidal CO2 is 85 mm Hg. Which of the following is the most appropriate treatment for this patient's condition?
Q602
A 58-year-old man presents with an occasional tremor in his left hand. While the tremor disappears when he moves his hand, he finds it increasingly difficult to type and feels his handwriting has gotten much smaller. He finds the tremor is more pronounced when he is stressed out at work. He also complains of a decrease in his sense of smell, mild constipation, difficulty sleeping, and increased urinary frequency – all of which he feels is him ‘just getting older’. No significant past medical history and no current medications. Vital signs are a pulse of 74/min, a respiratory rate of 14/min, a blood pressure of 130/70 mm Hg, and a temperature of 36.7°C (98.0°F). On physical examination, a resting tremor in the left hand is noted with mild rigidity in the upper limbs and mask-like faces. While performing finger-to-nose and rapid alternating movements, he has some difficulty. All his movements are slow. The sensation is intact. Gait is normal except for a decreased arm swing. Which of the following drugs acts directly on the receptors responsible for this patient’s condition?
Q603
A 54-year-old woman is diagnosed with locally-advanced invasive ductal carcinoma of the breast. She undergoes surgical resection, radiation therapy, and is now being started on adjunctive chemotherapy with cyclophosphamide and doxorubicin. The patient is scheduled for follow up by her primary care provider. Which of the following tests should be performed regularly to monitor her current treatment regimen?
Q604
A 62-year-old man comes to the physician for hematemesis and progressive heartburn over the past 5 days. Ten days ago, he was started on a medication to treat a condition that causes hearing difficulties and pain of the lower legs. He has no other history of serious illness. He has smoked 1 pack of cigarettes daily for the past 20 years. Physical examination shows bowing of the tibias. Upper endoscopy shows inflammation of the mucosa and a 1-cm punched-out ulcer in the distal esophagus. Which of the following drugs is the most likely cause of the patient's current condition?
Q605
A 58-year-old woman with breast cancer presents to her primary care physician for referral to a medical oncologist. She denies any personal history of blood clots in her past. Her past medical history is significant for preeclampsia, hypertension, polycystic ovarian syndrome, and hypercholesterolemia. She currently smokes 1 pack of cigarettes per day, drinks a glass of wine per day, and she currently denies any illicit drug use, despite a history of cocaine use. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 111/min and irregular, and respiratory rate 17/min. On physical examination, she has a grade 2/6 holosystolic murmur heard best at the left upper sternal border, bilateral bibasilar crackles on the lungs, and a normal abdominal examination. At her follow-up with the oncologist, they subsequently plan to start the patient on a highly emetic chemotherapeutic regimen. Which of the following regimens for the treatment of chemotherapy-induced emesis is most appropriate for patients on the same day of treatment?
Q606
A 65-year-old woman presents with memory problems for the past few weeks. Patient vividly describes how she forgot where she put her car keys this morning and did not remember to wish her grandson a happy birthday last week. Patient denies any cognitive problems, bowel/bladder incontinence, tremors, gait problems, or focal neurologic signs. Patient mentions she wants to take Ginkgo because her friend told her that it can help improve her brain function and prevent memory loss. Past medical history is significant for an acute cardiac event several years ago. Current medications are aspirin, carvedilol, and captopril. Patient denies any history of smoking, alcohol or recreational drug use. Patient is a widow, lives alone, and is able to perform all activities of daily living (ADLs) easily. No significant family history. Patient is afebrile and vital signs are within normal limits. Physical examination is unremarkable. Which of the following would be the most appropriate response to this patient’s request to take Ginkgo?
Q607
A man is brought into the emergency department by police. The patient was found somnolent in the park and did not respond to questioning. The patient's past medical history is unknown, and he is poorly kempt. The patient's personal belongings include prescription medications and illicit substances such as alprazolam, diazepam, marijuana, cocaine, alcohol, acetaminophen, and a baggie containing an unknown powder. His temperature is 97.0°F (36.1°C), blood pressure is 117/58 mmHg, pulse is 80/min, respirations are 9/min, and oxygen saturation is 91% on room air. Physical exam reveals pupils that do not respond to light bilaterally, and a somnolent patient who only withdraws his limbs to pain. Which of the following is the best next step in management?
Q608
A G1P0 mother gives birth to a male infant at 37 weeks gestation. She received adequate prenatal care and took all her prenatal vitamins. She is otherwise healthy and takes no medications. On the 1 month checkup, examination revealed a machine-like murmur heard at the left sternal border. Which of the following medications would be most appropriate to give the infant to address the murmur?
Q609
A 45-year-old man presents to the physician with limb weakness over the last 24 hours. He is an otherwise healthy man with no significant past medical history. On physical examination, his vital signs are stable. On neurological examination, there is decreased strength in the muscles of all 4 extremities, and the deep tendon reflexes are depressed. A detailed laboratory evaluation shows that he has generalized decreased neuronal excitability due to an electrolyte imbalance. Which of the following electrolyte imbalances is most likely to be present in the man?
Q610
A 50-year-old man is brought to his neurologist by his wife for bizarre behavior. On several occasions over the last several days, he had started to complain about ‘bunnies, tigers, and emus’ in the living room. The patient has a history of multiple sclerosis and was last seen by his primary neurologist 2 weeks ago for complaints of new left upper extremity weakness. On physical exam, his temperature is 37.0°C (98.6°F), the heart rate is 70/min, the blood pressure is 126/78 mm Hg, the respiratory rate is 16/min, and the oxygen saturation is 98% on room air. The exam is disrupted by the patient’s repeated comments about various animals in the exam room. His neurologic exam is unchanged from his neurologist's last documented exam. The basic metabolic panel is as follows:
Na+ 138 mEq/L
K+ 3.9 mEq/L
Cl- 101 mEq/L
HCO3- 24 mEq/L
BUN 10 mg/dL
Cr 0.6 mg/dL
Glucose 356 mg/dL
Which of the following is the most likely etiology of this patient's presentation?
Autonomic/CV Drugs US Medical PG Practice Questions and MCQs
Question 601: A 22-year-old woman is brought to the emergency department after being struck by a car while crossing the street. She has major depressive disorder with psychosis. Current medications include sertraline and haloperidol. Vital signs are within normal limits. X-ray of the lower extremity shows a mid-shaft femur fracture. The patient is taken to the operating room for surgical repair of the fracture. As the surgeon begins the internal fixation, the patient shows muscle rigidity and profuse diaphoresis. Her temperature is 39°C (102.2°F), pulse is 130/min, respirations are 24/min, and blood pressure is 146/70 mm Hg. The pupils are equal and reactive to light. The end tidal CO2 is 85 mm Hg. Which of the following is the most appropriate treatment for this patient's condition?
A. Fat embolectomy
B. Bromocriptine therapy
C. Propranolol therapy
D. Dantrolene therapy (Correct Answer)
E. Cyproheptadine therapy
Explanation: ***Dantrolene therapy***
- The patient's presentation with **muscle rigidity**, **hyperthermia** (39°C), **tachycardia**, **tachypnea**, **hypertension**, and **markedly elevated end-tidal CO2 (85 mm Hg)** developing acutely **during surgery** is diagnostic of **malignant hyperthermia (MH)**.
- MH is a life-threatening hypermetabolic crisis triggered by **volatile anesthetic agents** (e.g., sevoflurane, isoflurane) or **succinylcholine** in genetically susceptible individuals with mutations in the ryanodine receptor (RYR1).
- **Dantrolene** is the specific antidote for MH, working by inhibiting calcium release from the sarcoplasmic reticulum, thereby reducing muscle contractility and heat production.
- The **extremely elevated end-tidal CO2** reflects the hypermetabolic state and is a key diagnostic feature distinguishing MH from other conditions.
*Fat embolectomy*
- **Fat embolism syndrome** can occur 24-72 hours after long bone fractures and presents with **respiratory insufficiency**, **neurologic dysfunction** (confusion, altered mental status), and a **petechial rash** (classic triad).
- While the patient has a femur fracture, the **acute intraoperative onset**, **muscle rigidity**, and **markedly elevated end-tidal CO2** are not consistent with fat embolism syndrome.
*Bromocriptine therapy*
- **Bromocriptine**, a dopamine agonist, is used in the treatment of **neuroleptic malignant syndrome (NMS)**, which shares features with MH (rigidity, hyperthermia, autonomic instability).
- However, NMS typically develops over **days to weeks** after antipsychotic exposure or dose changes, not acutely during surgery.
- The **intraoperative timing** and **extremely elevated end-tidal CO2** point to malignant hyperthermia triggered by anesthetic agents, not NMS.
*Propranolol therapy*
- **Propranolol**, a non-selective beta-blocker, may help manage **tachycardia** and **hypertension** symptomatically.
- However, it does not address the underlying pathophysiology of MH (**uncontrolled calcium release** and **hypermetabolic crisis**) and is not a primary treatment.
- Dantrolene is the specific and life-saving therapy for MH.
*Cyproheptadine therapy*
- **Cyproheptadine**, a serotonin antagonist, is the treatment for **serotonin syndrome**, which can present with hyperthermia, rigidity, and autonomic instability.
- However, serotonin syndrome typically features **hyperreflexia** and **clonus** rather than the **lead-pipe rigidity** seen here, and develops after serotonergic drug exposure or interactions.
- The **intraoperative timing**, **muscle rigidity**, and **markedly elevated end-tidal CO2** are pathognomonic for **malignant hyperthermia**, not serotonin syndrome.
Question 602: A 58-year-old man presents with an occasional tremor in his left hand. While the tremor disappears when he moves his hand, he finds it increasingly difficult to type and feels his handwriting has gotten much smaller. He finds the tremor is more pronounced when he is stressed out at work. He also complains of a decrease in his sense of smell, mild constipation, difficulty sleeping, and increased urinary frequency – all of which he feels is him ‘just getting older’. No significant past medical history and no current medications. Vital signs are a pulse of 74/min, a respiratory rate of 14/min, a blood pressure of 130/70 mm Hg, and a temperature of 36.7°C (98.0°F). On physical examination, a resting tremor in the left hand is noted with mild rigidity in the upper limbs and mask-like faces. While performing finger-to-nose and rapid alternating movements, he has some difficulty. All his movements are slow. The sensation is intact. Gait is normal except for a decreased arm swing. Which of the following drugs acts directly on the receptors responsible for this patient’s condition?
A. Benztropine
B. Selegiline
C. Bromocriptine (Correct Answer)
D. Entacapone
E. Carbidopa
Explanation: ***Bromocriptine***
- This patient's symptoms (resting tremor, bradykinesia, rigidity, micrographia, decreased arm swing, mask-like facies, anosmia, constipation, sleep difficulties) are classic for **Parkinson's disease**. Bromocriptine is a **dopamine agonist** that directly stimulates dopamine receptors, mimicking the action of dopamine in the brain.
- Dopamine agonists are often used to treat Parkinson's disease, particularly in early stages or to reduce the "off" periods associated with levodopa therapy.
*Benztropine*
- Benztropine is an **anticholinergic** medication used to treat Parkinson's disease, primarily for tremor and rigidity.
- It acts by blocking muscarinic acetylcholine receptors, thereby restoring the balance between cholinergic and dopaminergic activity, but does not directly act on dopamine receptors.
*Selegiline*
- Selegiline is a **selective MAO-B inhibitor** that prevents the degradation of dopamine in the brain, thereby increasing its availability.
- It does not directly act on dopamine receptors but rather prolongs the action of existing dopamine.
*Entacapone*
- Entacapone is a **catechol-O-methyltransferase (COMT) inhibitor** that is used as an adjunctive therapy to levodopa/carbidopa.
- It works by preventing the peripheral breakdown of levodopa, thus increasing the amount of levodopa that reaches the brain and is converted to dopamine, but it does not directly stimulate dopamine receptors.
*Carbidopa*
- Carbidopa is a **peripheral DOPA decarboxylase inhibitor** that is always given in combination with levodopa.
- It prevents the peripheral conversion of levodopa to dopamine, allowing more levodopa to cross the blood-brain barrier and be converted to dopamine, but it has no direct action on dopamine receptors itself.
Question 603: A 54-year-old woman is diagnosed with locally-advanced invasive ductal carcinoma of the breast. She undergoes surgical resection, radiation therapy, and is now being started on adjunctive chemotherapy with cyclophosphamide and doxorubicin. The patient is scheduled for follow up by her primary care provider. Which of the following tests should be performed regularly to monitor her current treatment regimen?
A. No regular monitoring indicated
B. Chest radiograph
C. Cardiac MRI
D. ECG
E. Echocardiography (Correct Answer)
Explanation: ***Echocardiography***
- **Doxorubicin** is an anthracycline chemotherapy agent known for its dose-dependent **cardiotoxicity**, which can lead to **dilated cardiomyopathy** and heart failure.
- Regular echocardiography is crucial to monitor **left ventricular ejection fraction (LVEF)** and detect early signs of cardiac dysfunction, allowing for timely intervention or adjustment of treatment.
*No regular monitoring indicated*
- This is incorrect as **doxorubicin**, a component of the chemotherapy regimen, has significant cardiotoxic effects that require close monitoring to prevent severe cardiac complications.
- Neglecting monitoring could lead to irreversible cardiac damage.
*Chest radiograph*
- A chest radiograph primarily assesses lung fields and cardiac silhouette, but it is not sensitive enough to detect early-stage **doxorubicin-induced myocardial damage** or changes in **LVEF**.
- While useful for detecting pulmonary complications or metastases, it is not the primary tool for monitoring cardiotoxicity.
*Cardiac MRI*
- Cardiac MRI is a highly sensitive and specific imaging modality for assessing cardiac function and structure, but it is typically reserved for cases where echocardiography findings are equivocal or more detailed assessment is needed.
- It is not the routine or initial test for monitoring cardiotoxicity due to its higher cost and complexity.
*ECG*
- An ECG assesses the electrical activity of the heart and can detect arrhythmias or signs of ischemia, but it is generally not sufficient for monitoring **doxorubicin-induced cardiotoxicity**.
- While it can show nonspecific changes, it does not directly measure changes in **LVEF** or structural heart damage, which are key indicators of cardiotoxicity.
Question 604: A 62-year-old man comes to the physician for hematemesis and progressive heartburn over the past 5 days. Ten days ago, he was started on a medication to treat a condition that causes hearing difficulties and pain of the lower legs. He has no other history of serious illness. He has smoked 1 pack of cigarettes daily for the past 20 years. Physical examination shows bowing of the tibias. Upper endoscopy shows inflammation of the mucosa and a 1-cm punched-out ulcer in the distal esophagus. Which of the following drugs is the most likely cause of the patient's current condition?
A. Denosumab
B. Risedronate (Correct Answer)
C. Calcium citrate
D. Acetaminophen
E. Prednisolone
Explanation: ***Risedronate***
- The patient's history of hearing difficulties, lower leg pain, and bowing of the tibias suggests **Paget's disease of bone**. Bisphosphonates like **risedronate** are a common treatment for Paget's disease.
- Bisphosphonates are well-known to cause **esophagitis, esophageal ulcers**, and inflammation of the mucosa, leading to symptoms like **heartburn** and **hematemesis**.
*Denosumab*
- **Denosumab** is also used to treat Paget's disease but is a **monoclonal antibody** that inhibits osteoclast formation and function.
- It works differently from bisphosphonates and is not typically associated with **esophageal erosion** or **ulcers**.
*Calcium citrate*
- **Calcium citrate** is a calcium supplement often used to prevent or treat **osteoporosis**, not a primary treatment for Paget's disease.
- It does not cause **esophageal ulcers** or inflammation.
*Acetaminophen*
- **Acetaminophen** is an analgesic and antipyretic, not used for Paget's disease, and its primary side effect is **hepatotoxicity** at high doses.
- It **does not cause esophageal damage** or ulcers.
*Prednisolone*
- **Prednisolone** is a corticosteroid that can cause **gastric ulcers** but is not a first-line treatment for Paget's disease.
- While it can cause gastrointestinal side effects, it is less directly implicated in **esophageal ulcers** in this context compared to bisphosphonates.
Question 605: A 58-year-old woman with breast cancer presents to her primary care physician for referral to a medical oncologist. She denies any personal history of blood clots in her past. Her past medical history is significant for preeclampsia, hypertension, polycystic ovarian syndrome, and hypercholesterolemia. She currently smokes 1 pack of cigarettes per day, drinks a glass of wine per day, and she currently denies any illicit drug use, despite a history of cocaine use. The vital signs include: temperature 36.7°C (98.0°F), blood pressure 126/74 mm Hg, heart rate 111/min and irregular, and respiratory rate 17/min. On physical examination, she has a grade 2/6 holosystolic murmur heard best at the left upper sternal border, bilateral bibasilar crackles on the lungs, and a normal abdominal examination. At her follow-up with the oncologist, they subsequently plan to start the patient on a highly emetic chemotherapeutic regimen. Which of the following regimens for the treatment of chemotherapy-induced emesis is most appropriate for patients on the same day of treatment?
A. Prochlorperazine + dexamethasone + dronabinol
B. Dexamethasone + 5-HT3 receptor antagonist
C. Dronabinol + dexamethasone
D. Aprepitant + dronabinol
E. Aprepitant + dexamethasone + 5-HT3 receptor antagonist (Correct Answer)
Explanation: ***Aprepitant + dexamethasone + 5-HT3 receptor antagonist***
- This combination is the recommended antiemetic regimen for patients receiving **highly emetogenic chemotherapy** (HEC), providing broad-spectrum coverage against acute and delayed nausea and vomiting.
- **Aprepitant** is a neurokinin-1 (NK-1) receptor antagonist, **dexamethasone** is a corticosteroid, and **5-HT3 receptor antagonists** (e.g., ondansetron) block serotonin receptors, targeting multiple pathways involved in chemotherapy-induced nausea and vomiting (CINV).
*Prochlorperazine + dexamethasone + dronabinol*
- This combination is generally reserved for **breakthrough or refractory nausea and vomiting**, not for initial prophylaxis against HEC.
- **Prochlorperazine** is a dopamine antagonist, and **dronabinol** is a cannabinoid, which are less potent as primary prophylactic agents compared to NK-1 and 5-HT3 antagonists for HEC.
*Dexamethasone + 5-HT3 receptor antagonist*
- While effective for moderately emetogenic chemotherapy, this two-drug regimen is **insufficient for highly emetogenic chemotherapy (HEC)** due to the high risk and severity of CINV.
- It lacks the additional antiemetic action of an NK-1 receptor antagonist like aprepitant, which is crucial for HEC.
*Dronabinol + dexamethasone*
- This combination is not considered a first-line prophylactic regimen for HEC; **dronabinol** is typically used for **breakthrough CINV** or as an appetite stimulant.
- It lacks the primary broad-spectrum coverage provided by 5-HT3 receptor antagonists and NK-1 antagonists for preventing acute and delayed emesis from HEC.
*Aprepitant + dronabinol*
- This combination is **incomplete** for optimal HEC prophylaxis, as it misses the critical component of a **5-HT3 receptor antagonist** and a corticosteroid (dexamethasone).
- While aprepitant targets delayed emesis, and dronabinol can help with breakthrough, it's not the guideline-recommended multi-modal approach for strong initial prevention.
Question 606: A 65-year-old woman presents with memory problems for the past few weeks. Patient vividly describes how she forgot where she put her car keys this morning and did not remember to wish her grandson a happy birthday last week. Patient denies any cognitive problems, bowel/bladder incontinence, tremors, gait problems, or focal neurologic signs. Patient mentions she wants to take Ginkgo because her friend told her that it can help improve her brain function and prevent memory loss. Past medical history is significant for an acute cardiac event several years ago. Current medications are aspirin, carvedilol, and captopril. Patient denies any history of smoking, alcohol or recreational drug use. Patient is a widow, lives alone, and is able to perform all activities of daily living (ADLs) easily. No significant family history. Patient is afebrile and vital signs are within normal limits. Physical examination is unremarkable. Which of the following would be the most appropriate response to this patient’s request to take Ginkgo?
A. "Yes, ginkgo is widely used for improving brain function and memory."
B. “No, you have Alzheimer's disease and need to start donepezil.”
C. “No, herbal preparations are unsafe because they are not regulated by the FDA.”
D. "No, taking ginkgo will increase your risk for bleeding." (Correct Answer)
E. Yes, ginkgo may not help with your memory, but there is no risk of adverse events so it is safe to take.
Explanation: ***"No, taking ginkgo will increase your risk for bleeding."***
- **Ginkgo biloba** has known antithrombotic effects due to its inhibition of platelet-activating factor, which can increase the risk of **bleeding**, especially when combined with other antithrombotic agents like **aspirin**, which this patient is taking.
- Given her history of a cardiac event and current aspirin use, adding ginkgo would significantly raise her risk of hemorrhagic complications.
*"Yes, ginkgo is widely used for improving brain function and memory."*
- While ginkgo is popularly marketed for cognitive enhancement, there is **insufficient scientific evidence** to support its effectiveness in improving memory or preventing cognitive decline.
- Recommending it based solely on popular belief disregards evidence-based medicine and potential patient risks.
*"No, you have Alzheimer's disease and need to start donepezil.”*
- This is an inappropriate response as a diagnosis of **Alzheimer's disease** cannot be made based solely on the patient's self-reported memory issues; a comprehensive workup is required.
- Additionally, immediately prescribing **donepezil** without a confirmed diagnosis and without discussing potential risks or alternatives is premature and goes against diagnostic protocols.
*"No, herbal preparations are unsafe because they are not regulated by the FDA."*
- While it's true that **herbal preparations** are not regulated by the FDA in the same way as prescription drugs, labeling all such preparations as "unsafe" is an **overgeneralization**.
- The primary concern here is not just the lack of FDA regulation, but the specific **pharmacological interaction** of ginkgo with her current medications.
*"Yes, ginkgo may not help with your memory, but there is no risk of adverse events so it is safe to take."*
- This statement is incorrect because, as explained, ginkgo carries a significant **risk of adverse events**, particularly **increased bleeding risk**, especially in this patient due to her concomitant aspirin use.
- It is critical to acknowledge and address potential drug interactions and side effects, rather than dismissing them.
Question 607: A man is brought into the emergency department by police. The patient was found somnolent in the park and did not respond to questioning. The patient's past medical history is unknown, and he is poorly kempt. The patient's personal belongings include prescription medications and illicit substances such as alprazolam, diazepam, marijuana, cocaine, alcohol, acetaminophen, and a baggie containing an unknown powder. His temperature is 97.0°F (36.1°C), blood pressure is 117/58 mmHg, pulse is 80/min, respirations are 9/min, and oxygen saturation is 91% on room air. Physical exam reveals pupils that do not respond to light bilaterally, and a somnolent patient who only withdraws his limbs to pain. Which of the following is the best next step in management?
A. N-acetylcysteine
B. Supportive therapy, thiamine, and dextrose
C. Naloxone (Correct Answer)
D. Intubation
E. Flumazenil
Explanation: ***Naloxone***
- The patient exhibits classic signs of **opioid overdose** including **respiratory depression** (bradypnea, SpO2 91%), **miosis** (though noted as non-reactive, pinpoint pupils are common in opioid overdose), and altered mental status (somnolence, withdrawal to pain).
- Naloxone is an **opioid antagonist** that can rapidly reverse these effects and is indicated in suspected opioid overdose to improve breathing and consciousness.
*N-acetylcysteine*
- This is the antidote for **acetaminophen overdose**, which is possible given the presence of acetaminophen among the patient's belongings.
- However, the patient's acute symptoms of **severe respiratory and CNS depression** are not typical of acute acetaminophen toxicity and require more immediate intervention.
*Supportive therapy, thiamine, and dextrose*
- **Supportive therapy** (e.g., airway management) is crucial, and **thiamine and dextrose** are often given empirically to patients with altered mental status to address potential **Wernicke's encephalopathy** or **hypoglycemia**.
- While important general measures, these do not specifically target the immediate life-threatening respiratory depression and CNS depression so highly suggestive of opioid overdose.
*Intubation*
- While the patient has respiratory depression, **intubation** is an invasive procedure and should be considered if naloxone fails to improve respiratory status or if persistent airway compromise exists.
- The first step in suspected opioid overdose is typically to administer naloxone, as it may avoid the need for intubation.
*Flumazenil*
- **Flumazenil** is an antagonist for **benzodiazepine overdose**, and alprazolam and diazepam were found in the patient's possession.
- However, flumazenil can precipitate **withdrawal seizures** in chronic benzodiazepine users and is generally avoided in undifferentiated comatose patients, especially when mixed ingestions are suspected.
Question 608: A G1P0 mother gives birth to a male infant at 37 weeks gestation. She received adequate prenatal care and took all her prenatal vitamins. She is otherwise healthy and takes no medications. On the 1 month checkup, examination revealed a machine-like murmur heard at the left sternal border. Which of the following medications would be most appropriate to give the infant to address the murmur?
A. Prostaglandin E1
B. Prostaglandin E2
C. Indomethacin (Correct Answer)
D. Digoxin
E. Bosentan
Explanation: ***Indomethacin***
- A **machine-like murmur** heard at the left sternal border in an infant is highly characteristic of a **patent ductus arteriosus (PDA)**.
- **Indomethacin** is a **prostaglandin synthesis inhibitor** (NSAID) that promotes closure of a PDA by blocking prostaglandin production, which normally keeps the ductus arteriosus patent.
- **Clinical note:** While indomethacin is most effective when given to premature infants in the first 10-14 days of life, it remains the **pharmacological agent** for PDA closure, making it the correct answer among the options provided from a pharmacology perspective.
*Prostaglandin E1*
- **Prostaglandin E1 (alprostadil)** is used to *maintain* patency of the ductus arteriosus in **ductal-dependent congenital heart lesions** (e.g., transposition of great arteries, severe coarctation, pulmonary atresia).
- Administering PGE1 would worsen the PDA by preventing its closure, leading to increased left-to-right shunting and potential heart failure.
*Prostaglandin E2*
- Similar to PGE1, **prostaglandin E2** acts to *keep the ductus arteriosus open*, which is the opposite of the desired effect for a symptomatic PDA.
- PGE2 would exacerbate the infant's condition by preventing closure of the PDA.
*Digoxin*
- **Digoxin** is a cardiac glycoside that increases myocardial contractility by inhibiting Na⁺/K⁺-ATPase and is used to treat **congestive heart failure** and control ventricular rate in **atrial fibrillation/flutter**.
- While digoxin may be used for heart failure secondary to a large PDA, it does **not directly close the PDA** and does not address the underlying structural defect.
*Bosentan*
- **Bosentan** is an **endothelin receptor antagonist** used in the treatment of **pulmonary arterial hypertension**.
- It has no role in PDA closure and does not affect the patency of the ductus arteriosus.
Question 609: A 45-year-old man presents to the physician with limb weakness over the last 24 hours. He is an otherwise healthy man with no significant past medical history. On physical examination, his vital signs are stable. On neurological examination, there is decreased strength in the muscles of all 4 extremities, and the deep tendon reflexes are depressed. A detailed laboratory evaluation shows that he has generalized decreased neuronal excitability due to an electrolyte imbalance. Which of the following electrolyte imbalances is most likely to be present in the man?
A. Acute hypochloremia
B. Acute hypernatremia
C. Acute hyperkalemia
D. Acute hypercalcemia (Correct Answer)
E. Acute hypomagnesemia
Explanation: ***Acute hypercalcemia***
- **Hypercalcemia** causes decreased neuronal excitability by stabilizing nerve cell membranes, leading to **muscle weakness** and depressed deep tendon reflexes.
- The generalized weakness and hyporeflexia described are classic neurological manifestations of elevated calcium levels.
*Acute hypochloremia*
- **Hypochloremia** is often associated with gastrointestinal losses and can lead to **metabolic alkalosis** and muscle cramps but not generalized muscle weakness with depressed reflexes.
- Its direct effect on neuronal excitability to cause such profound weakness is not typical.
*Acute hypernatremia*
- **Hypernatremia** primarily causes neurological symptoms due to **cellular dehydration** and cerebral edema, leading to altered mental status, seizures, or coma.
- It does not typically present with generalized muscle weakness and depressed deep tendon reflexes due to decreased neuronal excitability in the manner described.
*Acute hyperkalemia*
- **Hyperkalemia** can cause muscle weakness and paralysis, but it often progresses to **cardiac arrhythmias** and is typically associated with **increased neuronal excitability** initially, before paralyzing effects.
- While it can lead to weakness, the generalized decreased excitability described is more characteristic of calcium imbalance.
*Acute hypomagnesemia*
- **Hypomagnesemia** typically increases neuronal excitability, leading to symptoms like **muscle cramps**, tremors, hyperreflexia, and even seizures.
- It does not cause generalized muscle weakness with depressed deep tendon reflexes as a primary manifestation of decreased neuronal excitability.
Question 610: A 50-year-old man is brought to his neurologist by his wife for bizarre behavior. On several occasions over the last several days, he had started to complain about ‘bunnies, tigers, and emus’ in the living room. The patient has a history of multiple sclerosis and was last seen by his primary neurologist 2 weeks ago for complaints of new left upper extremity weakness. On physical exam, his temperature is 37.0°C (98.6°F), the heart rate is 70/min, the blood pressure is 126/78 mm Hg, the respiratory rate is 16/min, and the oxygen saturation is 98% on room air. The exam is disrupted by the patient’s repeated comments about various animals in the exam room. His neurologic exam is unchanged from his neurologist's last documented exam. The basic metabolic panel is as follows:
Na+ 138 mEq/L
K+ 3.9 mEq/L
Cl- 101 mEq/L
HCO3- 24 mEq/L
BUN 10 mg/dL
Cr 0.6 mg/dL
Glucose 356 mg/dL
Which of the following is the most likely etiology of this patient's presentation?
A. Medication side effect
B. Metabolic abnormality (Correct Answer)
C. Recreational drug intoxication
D. Progression of neurologic disease
E. Primary psychiatric illness
Explanation: ***Metabolic abnormality***
- The patient's **blood glucose of 356 mg/dL** indicates significant hyperglycemia, a common cause of acute mental status changes, including **delirium** and **hallucinations**.
- This **metabolic derangement** is the most likely driver of his "bizarre behavior" and visual hallucinations of animals, especially given the acuteness of the presentation.
*Medication side effect*
- While many medications, including those for MS symptoms, can cause mental status changes, there is **no specific medication mentioned** or recent change in regimen to support this as the primary cause.
- The **elevated glucose** provides a more direct and evident cause for the observed symptoms compared to an unstated medication side effect.
*Recreational drug intoxication*
- There is **no information or clinical sign** in the vignette suggesting recreational drug use.
- While drug intoxication can cause hallucinations, the presence of **severe hyperglycemia** points to a clear alternative etiology.
*Progression of neurologic disease*
- Although the patient has MS and new weakness, his **neurologic exam is noted as unchanged** from two weeks prior, and his bizarre behavior is not typical for an MS exacerbation or progression.
- MS progression usually presents with **worsening focal neurological deficits** rather than isolated, acute psychiatric symptoms like visual hallucinations without other corresponding neurological changes.
*Primary psychiatric illness*
- The **acute onset** of symptoms, described as "bizarre behavior" and visual hallucinations, in a patient with no prior psychiatric history, makes a primary psychiatric illness less likely.
- The presence of a significant **metabolic abnormality (hyperglycemia)** provides a more plausible organic cause for the symptoms.