A 38-year-old woman comes to the physician for a follow-up examination. She was diagnosed with immune thrombocytopenic purpura at the age of 37 years and has been treated with glucocorticoids and intravenous immune globulin. She has visited the emergency department 3 times in the past 4 months for nose bleeds, which required cauterization. Her platelet counts on her previous visits were 18,320/mm3, 17,500/mm3, and 19,100/mm3. Current medications include dexamethasone and a multivitamin. She has no children. Her immunizations are up-to-date. Vital signs are within normal limits. Examination shows petechiae on the bilateral lower extremities. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and nontender; there is no organomegaly. Her hemoglobin concentration is 13.3 g/dL, leukocyte count is 8,100/mm3, and platelet count is 13,000/mm3. Her blood type is A negative. Serology for hepatitis C and HIV is negative. Which of the following is the most appropriate next step in management?
Q932
A 72-year-old male presents to his primary care physician complaining of increased urinary frequency and a weakened urinary stream. He has a history of gout, obesity, diabetes mellitus, and hyperlipidemia. He currently takes allopurinol, metformin, glyburide, and rosuvastatin. His temperature is 98.6°F (37°C), blood pressure is 130/85 mmHg, pulse is 90/min, and respirations are 18/min. Physical examination reveals an enlarged, non-tender prostate without nodules or masses. An ultrasound reveals a uniformly enlarged prostate that is 40mL in size. His physician starts him on a new medication. After taking the first dose, the patient experiences lightheadedness upon standing and has a syncopal event. Which of the following mechanisms of action is most consistent with the medication in question?
Q933
A 22-year-old man seeks help from a physician for his heroin addiction. He tells the doctor that he started using heroin at the age of 17 and gradually started increasing the dose. He has been trying to quit for the last 6 months after realizing the negative consequences of his addiction but has not succeeded because of the withdrawal symptoms. The physician suggests a drug that can be taken within a supervised rehabilitation program as a substitute for heroin to help alleviate withdrawal symptoms. The drug will then be tapered over time. He is further informed by the physician that this drug is not to be taken by the patient on his own and is not used for emergency reversal of opioid overdose. Which of the following drugs is most likely to have been recommended by the physician?
Q934
A 27-year-old man presents to the emergency department with nausea and vomiting. The patient started experiencing these symptoms shortly after arriving home from going out to eat at a seafood restaurant. His symptoms progressed and now he reports having an odd metallic taste in his mouth, diffuse pruritus, and blurry vision. His temperature is 99.0°F (37.2°C), blood pressure is 120/72 mmHg, pulse is 50/min, respirations are 17/min, and oxygen saturation is 99% on room air. Physical exam reveals bradycardia and an inability of the patient to differentiate hot versus cold; no rash can be appreciated on exam. Which of the following is the most likely etiology of this patient’s symptoms?
Q935
A 67-year-old man with stable coronary artery disease comes to the physician for a follow-up examination. Aside from occasional exertional chest pain on mowing the lawn or prolonged jogging, he feels well. He goes jogging for 20 minutes once a week and takes a tablet of sublingual nitroglycerine prior to his run to prevent anginal chest pain. The patient would like to run longer distances and asks the physician whether he could increase the dose of the drug prior to running. Administration of higher dosages of this drug is most likely to result in which of the following?
Q936
A 33-year-old woman comes to the emergency department for the evaluation of a headache and increased sweating for the last two hours. The patient also reports palpitations and nausea. Yesterday, she was started on venlafaxine for treatment-resistant depression. She took citalopram for four weeks, but stopped three days ago because her symptoms of depression did not improve. She does not smoke or drink alcohol. Her temperature is 39°C (102.2°F), pulse is 120/min, and blood pressure is 150/90 mm Hg. On mental status examination, the patient is only oriented to person, but not to place or time. Examination shows tremors in all extremities. She has impaired gait. Deep tendon reflexes are 3+ bilaterally. Which of the following is the most likely cause of this patient's symptoms?
Q937
A neonate suffering from neonatal respiratory distress syndrome is given supplemental oxygen. Which of the following is a possible consequence of oxygen therapy in this patient?
Q938
A 20-year-old man presents to the urgent care clinic complaining of nausea and vomiting for the past 2 hours. He just returned from a boating trip with his father, and while aboard they shared some packed potato salad and ham sandwiches. His dad denies any nausea or vomiting but does report minor dizziness. On examination he appears pale. The patient reports similar symptoms in the past when he was on a cruise trip to the Bahamas. What is the best medication for this patient at this time?
Q939
An 18-year-old male was brought to the emergency room after he caused an accident by driving at a slow speed as he was entering the freeway. He appears to have sustained no major injuries just minor scratches and lacerations, but appears to be paranoid, anxious, and is complaining of thirst. He has conjunctival injection and has slowed reflexes. A police officer explained that he had confiscated contraband from the vehicle of the male. Which of the following substances was most likely used by the male?
Q940
A 59-year-old male presents to his primary care physician complaining of muscle weakness. Approximately 6 months ago, he started to develop gradually worsening right arm weakness that progressed to difficulty walking about three months ago. His past medical history is notable for a transient ischemic attack, hypertension, hyperlipidemia, and diabetes mellitus. He takes aspirin, lisinopril, atorvastatin, metformin, and glyburide. He does not smoke and he drinks alcohol occasionally. Physical examination reveals 4/5 strength in right shoulder abduction and right arm flexion. A tremor is noted in the right hand. Strength is 5/5 throughout the left upper extremity. Patellar reflexes are 3+ bilaterally. Sensation to touch and vibration is intact in the bilateral upper and lower extremities. Tongue fasciculations are noted. Which of the following is the most appropriate treatment in this patient?
Autonomic/CV Drugs US Medical PG Practice Questions and MCQs
Question 931: A 38-year-old woman comes to the physician for a follow-up examination. She was diagnosed with immune thrombocytopenic purpura at the age of 37 years and has been treated with glucocorticoids and intravenous immune globulin. She has visited the emergency department 3 times in the past 4 months for nose bleeds, which required cauterization. Her platelet counts on her previous visits were 18,320/mm3, 17,500/mm3, and 19,100/mm3. Current medications include dexamethasone and a multivitamin. She has no children. Her immunizations are up-to-date. Vital signs are within normal limits. Examination shows petechiae on the bilateral lower extremities. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and nontender; there is no organomegaly. Her hemoglobin concentration is 13.3 g/dL, leukocyte count is 8,100/mm3, and platelet count is 13,000/mm3. Her blood type is A negative. Serology for hepatitis C and HIV is negative. Which of the following is the most appropriate next step in management?
A. Schedule splenectomy
B. Romiplostim therapy (Correct Answer)
C. Rituximab therapy
D. Observation and follow-up
E. Danazol therapy
Explanation: ***Romiplostim therapy***
- This patient has **chronic ITP refractory to corticosteroids and IVIG**, with persistent severe thrombocytopenia (platelet count 13,000/mm3) and recurrent bleeding (nosebleeds, petechiae).
- **Romiplostim** is a **thrombopoietin receptor agonist (TPO-RA)** that stimulates platelet production, making it an appropriate second-line treatment in this setting to increase platelet count and reduce bleeding risk.
*Schedule splenectomy*
- While splenectomy can be effective for refractory ITP, it is typically considered after failure of **pharmacological second-line therapies**, such as TPO-RAs or rituximab.
- The patient has not yet tried other non-surgical options that might increase platelet production with less invasive risk.
*Rituximab therapy*
- **Rituximab**, an **anti-CD20 antibody**, is another second-line treatment for ITP, reducing autoantibody production.
- It is a viable option, but TPO-RAs like romiplostim are often preferred or considered alongside rituximab as highly effective options for chronic, refractory ITP.
*Observation and follow-up*
- Given the patient's **persistent severe thrombocytopenia** (platelet count 13,000/mm3) and **recurrent bleeding episodes** requiring intervention, observation is not appropriate.
- There is a high risk of spontaneous bleeding, and active management is required to prevent life-threatening hemorrhage.
*Danazol therapy*
- **Danazol**, an attenuated androgen, has been used in ITP but is generally **less effective** than and has more side effects than other second-line agents like TPO-RAs or rituximab.
- It is not a preferred treatment for patients with severe refractory ITP and recurrent bleeding.
Question 932: A 72-year-old male presents to his primary care physician complaining of increased urinary frequency and a weakened urinary stream. He has a history of gout, obesity, diabetes mellitus, and hyperlipidemia. He currently takes allopurinol, metformin, glyburide, and rosuvastatin. His temperature is 98.6°F (37°C), blood pressure is 130/85 mmHg, pulse is 90/min, and respirations are 18/min. Physical examination reveals an enlarged, non-tender prostate without nodules or masses. An ultrasound reveals a uniformly enlarged prostate that is 40mL in size. His physician starts him on a new medication. After taking the first dose, the patient experiences lightheadedness upon standing and has a syncopal event. Which of the following mechanisms of action is most consistent with the medication in question?
A. Dihydropyridine calcium channel blocker
B. Selective muscarinic agonist
C. Alpha-2-adrenergic receptor agonist
D. Alpha-1-adrenergic receptor antagonist (Correct Answer)
E. Non-selective alpha receptor antagonist
Explanation: ***Alpha-1-adrenergic receptor antagonist***
- The patient's symptoms of **increased urinary frequency** and **weakened urinary stream** are consistent with **benign prostatic hyperplasia (BPH)**. The physical exam and ultrasound findings of an **enlarged, non-tender prostate** confirm this.
- The medication caused **lightheadedness upon standing** and a **syncopal event** after the first dose, which is indicative of **first-dose orthostatic hypotension**. This adverse effect is characteristic of **alpha-1-adrenergic receptor antagonists**, which relax smooth muscles in the prostate and bladder neck but can also cause vasodilation.
*Dihydropyridine calcium channel blocker*
- These drugs primarily relax **vascular smooth muscle**, leading to vasodilation and can cause **hypotension**, but **orthostatic hypotension** and syncope as a "first-dose effect" are less common compared to alpha-1 blockers.
- They are used to treat **hypertension** and **angina**, not directly for BPH symptoms.
*Selective muscarinic agonist*
- **Muscarinic agonists** (e.g., bethanechol) would **increase bladder contraction** and could worsen urinary outflow obstruction in BPH, not improve it.
- Their primary side effects include **diarrhea**, **nausea**, and **bradycardia**, not orthostatic hypotension and syncope.
*Alpha-2-adrenergic receptor agonist*
- **Alpha-2 agonists** (e.g., clonidine) typically **lower blood pressure** by reducing sympathetic outflow from the central nervous system, but they primarily cause **sedation** and **dry mouth**, and are not used for BPH.
- While they can cause hypotension, the specific presentation of first-dose syncope in the context of BPH treatment points away from this class.
*Non-selective alpha receptor antagonist*
- Although non-selective alpha antagonists can also cause **orthostatic hypotension** due to vasodilation, **selective alpha-1 antagonists** are the preferred choice for BPH due to their more targeted action on the prostate and bladder neck, and the question describes a direct therapy for BPH.
- Alpha-2 blockade is less relevant to BPH and can cause additional side effects.
Question 933: A 22-year-old man seeks help from a physician for his heroin addiction. He tells the doctor that he started using heroin at the age of 17 and gradually started increasing the dose. He has been trying to quit for the last 6 months after realizing the negative consequences of his addiction but has not succeeded because of the withdrawal symptoms. The physician suggests a drug that can be taken within a supervised rehabilitation program as a substitute for heroin to help alleviate withdrawal symptoms. The drug will then be tapered over time. He is further informed by the physician that this drug is not to be taken by the patient on his own and is not used for emergency reversal of opioid overdose. Which of the following drugs is most likely to have been recommended by the physician?
A. Clonidine
B. Naltrexone
C. Methadone (Correct Answer)
D. Naloxone
E. Codeine
Explanation: **Methadone**
- **Methadone** is a long-acting opioid agonist used in **medically supervised settings** for opioid addiction treatment, acting as a substitute to alleviate withdrawal symptoms and cravings.
- Its long half-life allows for **once-daily dosing**, making it suitable for gradual tapering and preventing acute withdrawal, but it is **not used for emergency reversal** of opioid overdose due to its slow onset and prolonged effects.
*Clonidine*
- **Clonidine** is an alpha-2 adrenergic agonist used to manage **autonomic symptoms of opioid withdrawal** (e.g., sweating, anxiety, muscle aches) but does not directly address opioid cravings or act as an opioid substitute.
- It works by **reducing sympathetic nervous system activity** and can cause sedation and hypotension, but it's not the primary opioid substitution therapy.
*Naltrexone*
- **Naltrexone** is an **opioid receptor antagonist** used to prevent relapse by blocking the euphoric effects of opioids, but it is not used to treat acute withdrawal symptoms.
- It should only be administered after **opioid detoxification is complete**, as giving it to someone with opioids in their system can precipitate severe, acute withdrawal.
*Naloxone*
- **Naloxone** is a pure **opioid receptor antagonist** used primarily to **rapidly reverse opioid overdose** by displacing opioids from their receptors in emergency situations.
- Due to its **short half-life** and immediate action, it is not suitable for the sustained management of withdrawal symptoms or as a substitute for opioids in addiction treatment programs.
*Codeine*
- **Codeine** is an opioid analgesic and antitussive that has a **high potential for abuse and dependence** itself, making it unsuitable as a substitute treatment for heroin addiction.
- Although it can alleviate pain and cough, using codeine in this context would essentially be **substituting one opioid addiction for another**, which is contrary to the goals of addiction treatment.
Question 934: A 27-year-old man presents to the emergency department with nausea and vomiting. The patient started experiencing these symptoms shortly after arriving home from going out to eat at a seafood restaurant. His symptoms progressed and now he reports having an odd metallic taste in his mouth, diffuse pruritus, and blurry vision. His temperature is 99.0°F (37.2°C), blood pressure is 120/72 mmHg, pulse is 50/min, respirations are 17/min, and oxygen saturation is 99% on room air. Physical exam reveals bradycardia and an inability of the patient to differentiate hot versus cold; no rash can be appreciated on exam. Which of the following is the most likely etiology of this patient’s symptoms?
A. Viral gastroenteritis
B. Scombrotoxin
C. Ciguatoxin (Correct Answer)
D. Type I hypersensitivity reaction
E. Tetrodotoxin
Explanation: ***Ciguatoxin***
- **Ciguatoxin** poisoning presents with gastrointestinal symptoms, neurological symptoms (such as **paresthesias, metallic taste, blurred vision, and temperature dysesthesia**), and **bradycardia**, often following consumption of specific reef fish.
- The patient's inability to differentiate hot from cold (**temperature dysesthesia**) is a classic and highly specific symptom for ciguatera poisoning.
*Viral gastroenteritis*
- While **nausea and vomiting** align with viral gastroenteritis, the presence of **neurological symptoms** like metallic taste, blurred vision, and temperature dysesthesia is not typical.
- **Bradycardia** is also not a common feature of viral gastroenteritis, which often presents with tachycardia due to dehydration.
*Scombrotoxin*
- **Scombrotoxin** poisoning typically causes symptoms similar to an **allergic reaction**, including flushing, headache, palpitations, and sometimes wheezing.
- It is characterized by the absence of neurological features like **temperature dysesthesia** or blurred vision.
*Type I hypersensitivity reaction*
- A **Type I hypersensitivity reaction** (anaphylaxis) would present with symptoms like urticaria, angioedema, bronchospasm, and hypotension, which are not described.
- While some features like pruritus can overlap, the specific neurological symptoms and bradycardia point away from a typical allergic reaction.
*Tetrodotoxin*
- **Tetrodotoxin**, found in pufferfish, causes rapid onset of **paresthesias, muscle weakness, paralysis, and respiratory failure**.
- **Bradycardia** and classic **temperature dysesthesia** are not the primary features, and the overall clinical picture does not align with tetrodotoxin poisoning.
Question 935: A 67-year-old man with stable coronary artery disease comes to the physician for a follow-up examination. Aside from occasional exertional chest pain on mowing the lawn or prolonged jogging, he feels well. He goes jogging for 20 minutes once a week and takes a tablet of sublingual nitroglycerine prior to his run to prevent anginal chest pain. The patient would like to run longer distances and asks the physician whether he could increase the dose of the drug prior to running. Administration of higher dosages of this drug is most likely to result in which of the following?
A. Reflex sympathetic activity (Correct Answer)
B. Coronary artery vasospasm
C. Rebound angina
D. Development of tolerance
E. Anaphylactic reaction
Explanation: **Correct: Reflex sympathetic activity**
- Higher doses of sublingual nitroglycerin cause more significant **vasodilation**, leading to a greater drop in **blood pressure**.
- This drop in blood pressure triggers the **baroreceptor reflex**, increasing heart rate and contractility via the sympathetic nervous system to maintain cardiac output.
*Incorrect: Coronary artery vasospasm*
- Nitroglycerin is a **vasodilator** and would prevent, not cause, coronary artery vasospasm.
- Coronary artery vasospasm is characteristic of **Prinzmetal angina** and is not typically a side effect of nitrates.
*Incorrect: Rebound angina*
- Rebound angina can occur with abrupt discontinuation of nitrates after prolonged use, not typically from a single higher dose.
- This phenomenon is linked to withdrawal, leading to increased risk of **angina exacerbation**.
*Incorrect: Development of tolerance*
- Tolerance (tachyphylaxis) to nitrates develops with prolonged or frequent exposure, requiring drug-free intervals to restore sensitivity.
- While it's a known issue with chronic nitrate use, a single higher dose is unlikely to immediately induce significant tolerance in the described context.
*Incorrect: Anaphylactic reaction*
- Anaphylaxis is a severe, acute **allergic reaction** and is extremely rare with nitroglycerin.
- Symptoms include widespread urticaria, angioedema, bronchospasm, and hypotension, which are not expected side effects of increased dosage.
Question 936: A 33-year-old woman comes to the emergency department for the evaluation of a headache and increased sweating for the last two hours. The patient also reports palpitations and nausea. Yesterday, she was started on venlafaxine for treatment-resistant depression. She took citalopram for four weeks, but stopped three days ago because her symptoms of depression did not improve. She does not smoke or drink alcohol. Her temperature is 39°C (102.2°F), pulse is 120/min, and blood pressure is 150/90 mm Hg. On mental status examination, the patient is only oriented to person, but not to place or time. Examination shows tremors in all extremities. She has impaired gait. Deep tendon reflexes are 3+ bilaterally. Which of the following is the most likely cause of this patient's symptoms?
A. Increased CNS serotonergic activity (Correct Answer)
B. Anticholinergic toxicity
C. Dopamine receptor blockade
D. Abnormal ryanodine receptor
E. Suspected amphetamine intake
Explanation: ***Increased CNS serotonergic activity***
- The patient's symptoms, including **headache**, **sweating**, **palpitations**, **nausea**, **fever (39°C)**, **tachycardia**, **hypertension**, **disorientation**, **tremors**, **impaired gait**, and **hyperreflexia**, are classic signs of **serotonin syndrome**.
- This syndrome is precipitated by the recent initiation of **venlafaxine** (an SNRI) after stopping **citalopram** (an SSRI) just three days prior, leading to an excessive buildup of **serotonin** in the central nervous system.
*Anticholinergic toxicity*
- This condition presents with symptoms such as **dry mouth**, **dilated pupils**, **blurred vision**, **urinary retention**, and **constipation**, which are not seen in this patient.
- While it can cause **confusion** and **tachycardia**, the prominent **sweating**, **hyperreflexia**, and **tremors** are inconsistent with anticholinergic overdose.
*Dopamine receptor blockade*
- This is typically associated with **extrapyramidal symptoms** such as **dystonia**, **akathisia**, **parkinsonism**, and **neuroleptic malignant syndrome**, rather than the specific constellation of symptoms described.
- **Neuroleptic malignant syndrome** shares some features like fever and autonomic instability, but it typically involves severe **muscle rigidity** (lead-pipe rigidity) and **bradykinesia**, in contrast to the tremors and hyperreflexia observed here.
*Abnormal ryanodine receptor*
- An abnormal ryanodine receptor is associated with **malignant hyperthermia**, a life-threatening condition triggered by certain **anesthetics** or **succinylcholine**.
- While it causes **fever**, **tachycardia**, and **muscle rigidity**, it is unlikely given the patient's medication history and the absence of anesthetic exposure.
*Suspected amphetamine intake*
- Amphetamine intoxication can cause **tachycardia**, **hypertension**, **agitation**, and **hyperthermia**, which overlap with some of the patient's symptoms.
- However, the rapid onset of symptoms immediately following a change in antidepressant medication, particularly the presence of **hyperreflexia** and **tremors**, makes **serotonin syndrome** a more direct and likely explanation in this clinical context.
Question 937: A neonate suffering from neonatal respiratory distress syndrome is given supplemental oxygen. Which of the following is a possible consequence of oxygen therapy in this patient?
A. Anosmia
B. Atelectasis
C. Atopy
D. Blindness (Correct Answer)
E. Cardiac anomalies
Explanation: ***Blindness***
- High concentrations of supplemental oxygen in neonates, particularly premature infants, can lead to **retinopathy of prematurity (ROP)**.
- ROP involves abnormal growth of blood vessels in the retina, which can detach the retina and result in **permanent blindness**.
*Anosmia*
- **Anosmia** is the loss of the sense of smell, typically caused by nasal polyps, head trauma, or certain viral infections.
- It is **not a recognized complication** of oxygen therapy in neonates.
*Atelectasis*
- **Atelectasis** refers to the collapse of lung tissue, which can be caused by bronchial obstruction or hypoventilation.
- While underlying respiratory distress syndrome can predispose to atelectasis, oxygen therapy itself typically aims to improve ventilation and **does not directly cause atelectasis**.
*Atopy*
- **Atopy** is a genetic predisposition to developing allergic diseases such as asthma, eczema, and allergic rhinitis.
- It is **unrelated to oxygen therapy** and is determined by genetic factors and environmental exposures.
*Cardiac anomalies*
- **Cardiac anomalies** (congenital heart defects) are structural problems in the heart present at birth, resulting from abnormal fetal development.
- They are **not a consequence of oxygen therapy** given postpartum; oxygen therapy may be used to manage their symptoms.
Question 938: A 20-year-old man presents to the urgent care clinic complaining of nausea and vomiting for the past 2 hours. He just returned from a boating trip with his father, and while aboard they shared some packed potato salad and ham sandwiches. His dad denies any nausea or vomiting but does report minor dizziness. On examination he appears pale. The patient reports similar symptoms in the past when he was on a cruise trip to the Bahamas. What is the best medication for this patient at this time?
A. Diphenhydramine (Correct Answer)
B. Ondansetron
C. Loratadine
D. Guaifenesin
E. Loperamide
Explanation: ***Diphenhydramine***
- This patient's symptoms (nausea, vomiting after a boating trip, similar past experience on a cruise, father's dizziness) strongly suggest **motion sickness**.
- **Diphenhydramine** is an **antihistamine** with significant **anticholinergic** properties that effectively blocks H1 receptors in the brainstem, helping to prevent and treat motion sickness.
*Ondansetron*
- Ondansetron is a **serotonin 5-HT3 receptor antagonist** primarily used for **chemotherapy-induced nausea and vomiting** and post-operative nausea, not motion sickness.
- While it reduces nausea, its efficacy for motion sickness is limited because motion sickness primarily involves histamine and muscarinic acetylcholine pathways.
*Loratadine*
- Loratadine is a **second-generation antihistamine** primarily used for **allergies** due to its selective peripheral H1 receptor blockade.
- It has minimal sedating and central anticholinergic effects, making it ineffective for motion sickness, which requires central nervous system activity.
*Guaifenesin*
- Guaifenesin is an **expectorant** used to thin and loosen mucus in the airways for conditions like coughs and colds.
- It has no antiemetic properties and is not indicated for nausea and vomiting or motion sickness.
*Loperamide*
- Loperamide is an **opioid receptor agonist** that acts on receptors in the gut to decrease intestinal motility and is used to treat **diarrhea**.
- It has no effect on nausea or vomiting and is contraindicated in patients with such symptoms unless diarrhea is also present and its cause is confirmed.
Question 939: An 18-year-old male was brought to the emergency room after he caused an accident by driving at a slow speed as he was entering the freeway. He appears to have sustained no major injuries just minor scratches and lacerations, but appears to be paranoid, anxious, and is complaining of thirst. He has conjunctival injection and has slowed reflexes. A police officer explained that he had confiscated contraband from the vehicle of the male. Which of the following substances was most likely used by the male?
A. Cocaine
B. Heroin
C. Phencyclidine (PCP)
D. Marijuana (Correct Answer)
E. Alprazolam
Explanation: ***Marijuana***
- The combination of **paranoia, anxiety, conjunctival injection, slowed reflexes, and thirst (dry mouth)** is highly characteristic of **marijuana intoxication**.
- Driving at a **slow speed** and causing an accident also aligns with the impaired judgment and motor skills associated with cannabis use.
*Cocaine*
- Cocaine intoxication typically causes **euphoria, increased energy, dilated pupils (mydriasis), and tachycardia**, not slowed reflexes or conjunctival injection.
- Users would generally exhibit **agitation and paranoia** but not the sedating effects of driving slowly.
*Heroin*
- Heroin (an opioid) intoxication is characterized by **respiratory depression, pinpoint pupils (miosis), sedation, and euphoria**, which are not seen in this patient.
- The patient's paranoia and anxiety are not typical features of acute opioid intoxication.
*Phencyclidine (PCP)*
- PCP intoxication often presents with severe **agitation, aggression, nystagmus, hypertension, and dissociative symptoms**, along with a high tolerance to pain.
- While paranoia can occur, the overall clinical picture, especially the absence of aggression and nystagmus, makes PCP less likely.
*Alprazolam*
- Alprazolam, a benzodiazepine, primarily causes **sedation, drowsiness, ataxia, and slurred speech**.
- While it can impair driving and cause slowed reflexes, it typically does not cause paranoia, conjunctival injection, or thirst.
Question 940: A 59-year-old male presents to his primary care physician complaining of muscle weakness. Approximately 6 months ago, he started to develop gradually worsening right arm weakness that progressed to difficulty walking about three months ago. His past medical history is notable for a transient ischemic attack, hypertension, hyperlipidemia, and diabetes mellitus. He takes aspirin, lisinopril, atorvastatin, metformin, and glyburide. He does not smoke and he drinks alcohol occasionally. Physical examination reveals 4/5 strength in right shoulder abduction and right arm flexion. A tremor is noted in the right hand. Strength is 5/5 throughout the left upper extremity. Patellar reflexes are 3+ bilaterally. Sensation to touch and vibration is intact in the bilateral upper and lower extremities. Tongue fasciculations are noted. Which of the following is the most appropriate treatment in this patient?
A. Bromocriptine
B. Selegiline
C. Benztropine
D. Natalizumab
E. Riluzole (Correct Answer)
Explanation: ***Riluzole***
- This patient's symptoms (progressing limb weakness, hyperreflexia, and tongue fasciculations) are classic for **Amyotrophic Lateral Sclerosis (ALS)**, a progressive neurodegenerative disease.
- **Riluzole** is a neuroprotective agent approved for ALS that can modestly extend survival and delay the need for tracheostomy.
*Bromocriptine*
- **Bromocriptine** is a dopamine agonist primarily used in the treatment of **Parkinson's disease** and certain endocrine disorders like hyperprolactinemia.
- It does not have a role in the management of Amyotrophic Lateral Sclerosis (ALS).
*Selegiline*
- **Selegiline** is a selective monoamine oxidase B (MAO-B) inhibitor used to treat **Parkinson's disease**, often as an adjunct to levodopa.
- It is not indicated for the treatment of ALS.
*Benztropine*
- **Benztropine** is an anticholinergic medication primarily used to treat **Parkinson's disease** symptoms (especially tremor and rigidity) and **extrapyramidal symptoms** induced by antipsychotic drugs.
- It has no therapeutic benefit for ALS.
*Natalizumab*
- **Natalizumab** is a monoclonal antibody used to treat **multiple sclerosis** and Crohn's disease by preventing immune cells from crossing the blood-brain barrier.
- It works through a different mechanism (integrin blockade) and is not used in the treatment of ALS.
