A 40-year-old woman comes to the physician because of a 2 week history of anorexia and a feeling of dryness in the mouth; she has had a 5.8-kg (12.8-lb) weight loss during this period. She also complains of fatigue and inability to carry out daily chores. One year ago, she was diagnosed with advanced cervical carcinoma, metastatic to the pancreas, and is being treated with combination chemotherapy. She is 157 cm (5 ft 2 in) tall and weighs 47 kg (103.6 lb); BMI is 19.1 kg/m2. She appears thin and pale. Her temperature is 37.7°C (99.8°F), blood pressure is 110/68 mm Hg, pulse is 105/min, and respirations are 28/min. There is generalized weakness and atrophy of the skeletal muscles. Which of the following is the most appropriate next step in management?
Q172
A 38-year-old woman presents to her primary care physician for evaluation of 3 months of increasing fatigue. She states that she feels normal in the morning, but that her fatigue gets worse throughout the day. Specifically, she says that her head drops when trying to perform overhead tasks. She also says that she experiences double vision when watching television or reading a book. On physical exam, there is right-sided ptosis after sustaining upward gaze for a 2 minutes. Which of the following treatments may be effective in treating this patient's diagnosis?
Q173
An investigator is developing a drug that selectively inhibits the retrograde axonal transport of rabies virus towards the central nervous system. To achieve this effect, this drug must target which of the following?
Q174
A 63-year-old man comes to the physician for blurry vision and increased difficulty walking over the past month. He feels very fatigued after watering his garden but feels better after taking a nap. He has not had any recent illness. He has smoked one pack of cigarettes daily for 35 years. Examination shows drooping of the upper eyelids bilaterally and diminished motor strength in the upper extremities. Sensation to light touch and deep tendon reflexes are intact. An x-ray of the chest shows low lung volumes bilaterally. A drug with which of the following mechanisms of action is most appropriate for this patient?
Q175
A 37-year-old woman presents with a 3-day history of fever. Past medical history is significant for chronic schizophrenia, managed with an antipsychotic medication. The patient has a low-grade fever and is slightly tachycardic. Physical examination is significant for the presence of tonsillar exudates. A CBC shows a markedly decreased WBC count. The patient’s antipsychotic medication is immediately discontinued. Which of the following is the antipsychotic medication that could have caused this problem?
Q176
A 75-year-old woman with metastatic colon cancer comes to the physician requesting assistance in ending her life. She states: “I just can't take it anymore; the pain is unbearable. Please help me die.” Current medications include 10 mg oral hydrocodone every 12 hours. Her cancer has progressed despite chemotherapy and she is very frail. She lives alone and has no close family. Which of the following is the most appropriate initial action by the physician?
Q177
A 34-year-old woman comes to the physician with fever and malaise. For the past 2 days, she has felt fatigued and weak and has had chills. Last night, she had a temperature of 40.8°C (104.2°F). She has also had difficulty swallowing since this morning. The patient was recently diagnosed with Graves disease and started on methimazole. She appears uncomfortable. Her temperature is 38.3°C (100.9°F), pulse is 95/min, and blood pressure is 134/74 mm Hg. The oropharynx is erythematous without exudate. The lungs are clear to auscultation. Laboratory studies show:
Hematocrit 42%
Hemoglobin 13.4 g/dL
Leukocyte count 3,200/mm3
Segmented neutrophils 9%
Basophils < 1%
Eosinophils < 1%
Lymphocytes 79%
Monocytes 11%
Platelet count 230,000/mm3
Which of the following is the most appropriate next step in management?
Q178
A 24-year-old man is taken to the emergency department by local law enforcement after they witnessed him physically assaulting a complete stranger. The officers report that they saw his eyes “moving back and forth quickly” and noted that he was very red-faced. The patient has no significant past medical or psychiatric history. His vital signs include: temperature 38.0°C (100.4°F), blood pressure 110/70 mm Hg, pulse 102/min, and respiratory rate 25/min. On physical examination, the patient is belligerent and refuses to cooperate during the examination. Rotary nystagmus is noted. Which of the following drugs would most likely be present in a urine toxicology screen from this patient?
Q179
You are called to the bedside of a 75-year-old woman, who is post-op day 4 from a right total hip replacement. The patient appears agitated; she is trying to pull out her IV, and for the past 4 hours she has been accusing the nursing staff of trying to poison her. Her family notes that this behavior is completely different from her baseline; she has not shown any signs of memory loss or behavioral changes at home prior to the surgery. You note that she still has an indwelling catheter. She continues on an opioid-based pain regimen. All of the following are potential contributors to the patient’s presentation EXCEPT:
Q180
A 19-year-old woman comes to the physician because of increased sweating for the past 6 months. She experiences severe sweating that is triggered by stressful situations and speaking in public. She is failing one of her university classes because of her avoidance of public speaking. She has not had any fevers, chills, weight loss, or night sweats. Her temperature is 36.6°C (98°F). Physical examination shows moist skin in the axillae and on the palms, soles, and face. Which of the following drugs is most likely to be effective for this patient's condition?
Cholinergic/Adrenergic drugs US Medical PG Practice Questions and MCQs
Question 171: A 40-year-old woman comes to the physician because of a 2 week history of anorexia and a feeling of dryness in the mouth; she has had a 5.8-kg (12.8-lb) weight loss during this period. She also complains of fatigue and inability to carry out daily chores. One year ago, she was diagnosed with advanced cervical carcinoma, metastatic to the pancreas, and is being treated with combination chemotherapy. She is 157 cm (5 ft 2 in) tall and weighs 47 kg (103.6 lb); BMI is 19.1 kg/m2. She appears thin and pale. Her temperature is 37.7°C (99.8°F), blood pressure is 110/68 mm Hg, pulse is 105/min, and respirations are 28/min. There is generalized weakness and atrophy of the skeletal muscles. Which of the following is the most appropriate next step in management?
A. Cognitive behavioral therapy
B. Megestrol acetate (Correct Answer)
C. Mirtazapine
D. Cyproheptadine
E. Dronabinol
Explanation: ***Megestrol acetate***
- This patient exhibits signs of **cachexia** (anorexia, significant weight loss, fatigue, muscle atrophy) secondary to advanced cancer and chemotherapy. **Megestrol acetate** is a synthetic progestin that acts as an appetite stimulant and antigonadotropin, making it effective for treating **cancer-related anorexia-cachexia syndrome**.
- It works by stimulating appetite and promoting weight gain, primarily by increasing fat mass, and is a **first-line agent** for this condition.
*Cognitive behavioral therapy*
- While beneficial for psychological stress or depression that might accompany cancer, **CBT** does not directly address the underlying physiological mechanisms of **cancer cachexia** or significantly improve appetite and weight loss.
- Its primary role is in managing anxiety, mood disorders, and coping strategies, not as a primary treatment for **anorexia-cachexia syndrome**.
*Mirtazapine*
- **Mirtazapine** is an antidepressant that can cause **weight gain** as a side effect by increasing appetite, but its primary indication is for depression.
- It is not the most appropriate first-line choice for severe cancer-related **anorexia-cachexia syndrome** compared to more potent appetite stimulants like megestrol acetate.
*Cyproheptadine*
- **Cyproheptadine** is a **first-generation antihistamine** with **serotonin antagonist** properties that can stimulate appetite, often used in cases of **failure to thrive** in children or in specific rare conditions.
- However, it is generally considered less effective than megestrol acetate for treating **cancer-related cachexia** in adults and is associated with more sedative side effects.
*Dronabinol*
- **Dronabinol** is a **cannabinoid receptor agonist** that stimulates appetite and is primarily indicated for AIDS-related anorexia or chemotherapy-induced **nausea and vomiting**.
- While it can improve appetite, **megestrol acetate** has demonstrated superior efficacy for weight gain and appetite stimulation in **cancer-related cachexia**, making it the preferred initial treatment.
Question 172: A 38-year-old woman presents to her primary care physician for evaluation of 3 months of increasing fatigue. She states that she feels normal in the morning, but that her fatigue gets worse throughout the day. Specifically, she says that her head drops when trying to perform overhead tasks. She also says that she experiences double vision when watching television or reading a book. On physical exam, there is right-sided ptosis after sustaining upward gaze for a 2 minutes. Which of the following treatments may be effective in treating this patient's diagnosis?
A. Chemotherapy
B. Vaccination
C. Thymectomy (Correct Answer)
D. Antitoxin
E. Riluzole
Explanation: ***Thymectomy***
- This patient's symptoms (fatigue worsening throughout the day, ptosis, diplopia, and head drop with overhead tasks) are classic for **myasthenia gravis (MG)**. Thymectomy is a definitive treatment option, especially for patients with a **thymoma** or generalized MG.
- Approximately 10-15% of MG patients have a thymoma, and many others have thymic hyperplasia. **Thymectomy** can lead to remission or improvement in a significant number of patients by reducing the production of abnormal antibodies.
*Chemotherapy*
- Chemotherapy is primarily used for treating cancers and is not a first-line treatment for autoimmune diseases like **myasthenia gravis**.
- While some immunosuppressants used in cancer may also be used in MG, chemotherapy, in its primary role, is not indicated for this condition.
*Vaccination*
- Vaccination is a preventive measure against infectious diseases and plays no role in the direct treatment of **myasthenia gravis**, which is an autoimmune disorder.
- While MG patients should receive recommended vaccinations, these do not treat the underlying disease.
*Antitoxin*
- Antitoxins are used to neutralize toxins produced by bacteria, such as in **botulism** or **tetanus**.
- Myasthenia gravis is an autoimmune disease involving antibodies against acetylcholine receptors, not a bacterial toxin.
*Riluzole*
- **Riluzole** is a medication approved for the treatment of **amyotrophic lateral sclerosis (ALS)**, a progressive neurodegenerative disease.
- It works by reducing glutamate-mediated excitotoxicity and has no role in the pathophysiology or treatment of **myasthenia gravis**.
Question 173: An investigator is developing a drug that selectively inhibits the retrograde axonal transport of rabies virus towards the central nervous system. To achieve this effect, this drug must target which of the following?
A. Dynein (Correct Answer)
B. Tubulin
C. Nidogen
D. Kinesin
E. Acetylcholine
Explanation: ***Dynein***
- **Dynein** is a microtubule-dependent motor protein responsible for **retrograde axonal transport**, moving cargo (like rabies virus) away from the axon terminals towards the cell body and ultimately the central nervous system.
- Inhibiting dynein would therefore prevent the **rabies virus** from traveling from the site of infection (e.g., muscle cell) to the central nervous system.
*Tubulin*
- **Tubulin** is the primary protein subunit that polymerizes to form **microtubules**, which serve as the tracks for axonal transport.
- Inhibiting tubulin polymerization would disrupt both **anterograde** and **retrograde transport** nonspecifically, leading to severe neurotoxicity rather than selective inhibition of rabies virus transport.
*Nidogen*
- **Nidogen** (also known as entactin) is a glycoprotein component of the **basal lamina**, an extracellular matrix structure.
- It plays a role in cell adhesion and tissue organization but is not directly involved in the intracellular motor processes of axonal transport.
*Kinesin*
- **Kinesin** is a microtubule-dependent motor protein primarily responsible for **anterograde axonal transport**, moving cargo from the cell body towards the axon terminals.
- Inhibiting kinesin would disrupt the outward movement of vesicles and organelles, but would not prevent the **inward retrograde transport** of the rabies virus.
*Acetylcholine*
- **Acetylcholine** is a neurotransmitter that plays a role in synaptic transmission in both the peripheral and central nervous systems.
- While rabies virus can affect neuronal function, acetylcholine itself is not a motor protein or a structural component directly involved in the physical process of **axonal transport**.
Question 174: A 63-year-old man comes to the physician for blurry vision and increased difficulty walking over the past month. He feels very fatigued after watering his garden but feels better after taking a nap. He has not had any recent illness. He has smoked one pack of cigarettes daily for 35 years. Examination shows drooping of the upper eyelids bilaterally and diminished motor strength in the upper extremities. Sensation to light touch and deep tendon reflexes are intact. An x-ray of the chest shows low lung volumes bilaterally. A drug with which of the following mechanisms of action is most appropriate for this patient?
A. Inhibition of acetylcholinesterase (Correct Answer)
B. Stimulation of D2 receptors
C. Regeneration of acetylcholinesterase
D. Inhibition of muscarinic ACh receptor
E. Stimulation of β2 adrenergic receptors
Explanation: ***Inhibition of acetylcholinesterase***
- The patient's symptoms (blurry vision, difficulty walking, fatigue improving with rest, ptosis, and proximal muscle weakness) are classic for **Lambert-Eaton myasthenic syndrome (LEMS)**, strongly associated with **small cell lung cancer** given his heavy smoking history and chest X-ray findings.
- LEMS is caused by **autoantibodies against presynaptic voltage-gated calcium channels** at the neuromuscular junction, which **reduce acetylcholine release**.
- While **3,4-diaminopyridine** (a potassium channel blocker that increases ACh release) is the preferred treatment for LEMS, it is not among the options; **acetylcholinesterase inhibitors** (e.g., pyridostigmine) can provide symptomatic benefit by increasing acetylcholine availability in the synaptic cleft, making this the best available option.
- Note: Acetylcholinesterase inhibitors are more effective in **myasthenia gravis** than in LEMS, but may still provide modest improvement.
*Incorrect: Stimulation of D2 receptors*
- **D2 receptor agonists** (e.g., pramipexole, ropinirole) are used to treat **Parkinson's disease**, which presents with **resting tremor, rigidity, bradykinesia, and postural instability**.
- The patient's fatigable weakness, ptosis, and improvement with rest are characteristic of a neuromuscular junction disorder, not a basal ganglia disorder.
*Incorrect: Regeneration of acetylcholinesterase*
- **Acetylcholinesterase reactivators** like **pralidoxime** are used to treat **organophosphate poisoning**, where acetylcholinesterase is irreversibly phosphorylated.
- This patient has no history of pesticide exposure or cholinergic crisis symptoms (salivation, lacrimation, miosis, bronchospasm).
*Incorrect: Inhibition of muscarinic ACh receptor*
- **Muscarinic antagonists** (e.g., atropine, scopolamine) block parasympathetic effects and would **worsen neuromuscular transmission** by reducing cholinergic activity.
- Blocking acetylcholine receptors would exacerbate the patient's muscle weakness and ptosis.
*Incorrect: Stimulation of β2 adrenergic receptors*
- **Beta-2 agonists** (e.g., albuterol, salmeterol) are bronchodilators used for **asthma and COPD**.
- While the patient has a significant smoking history, his presentation is dominated by neuromuscular symptoms, not respiratory distress or bronchospasm.
Question 175: A 37-year-old woman presents with a 3-day history of fever. Past medical history is significant for chronic schizophrenia, managed with an antipsychotic medication. The patient has a low-grade fever and is slightly tachycardic. Physical examination is significant for the presence of tonsillar exudates. A CBC shows a markedly decreased WBC count. The patient’s antipsychotic medication is immediately discontinued. Which of the following is the antipsychotic medication that could have caused this problem?
A. Haloperidol
B. Risperidone
C. Olanzapine
D. Quetiapine
E. Clozapine (Correct Answer)
Explanation: ***Clozapine***
- **Clozapine** is well-known for its rare but severe side effect of **agranulocytosis**, characterized by a marked decrease in the white blood cell count, particularly neutrophils.
- The patient's symptoms of fever, tonsillar exudates (indicating infection), and significantly decreased WBC count strongly suggest **agranulocytosis** induced by clozapine.
*Haloperidol*
- **Haloperidol** is a typical antipsychotic and is generally not associated with a high risk of agranulocytosis.
- Its primary side effects often include **extrapyramidal symptoms** and QT prolongation.
*Risperidone*
- **Risperidone** is an atypical antipsychotic with a low association with agranulocytosis.
- Common side effects include **sedation**, weight gain, and hyperprolactinemia.
*Olanzapine*
- While **olanzapine** is an atypical antipsychotic, it is not primarily associated with agranulocytosis, although it can cause other hematologic abnormalities rarely.
- It is more commonly linked to **metabolic syndrome**, significant weight gain, and sedation.
*Quetiapine*
- **Quetiapine** is another atypical antipsychotic with a very low incidence of agranulocytosis.
- Its frequent side effects include **sedation**, orthostatic hypotension, and weight gain.
Question 176: A 75-year-old woman with metastatic colon cancer comes to the physician requesting assistance in ending her life. She states: “I just can't take it anymore; the pain is unbearable. Please help me die.” Current medications include 10 mg oral hydrocodone every 12 hours. Her cancer has progressed despite chemotherapy and she is very frail. She lives alone and has no close family. Which of the following is the most appropriate initial action by the physician?
A. Consult with the local ethics committee
B. Submit a referral to psychiatry
C. Submit a referral to hospice care
D. Increase her pain medication dose (Correct Answer)
E. Initiate authorization of physician-assisted suicide
Explanation: ***Increase her pain medication dose***
- The patient's request to end her life is directly linked to "unbearable pain" and her current pain regimen (10 mg hydrocodone every 12 hours) is **sub-therapeutic** for metastatic cancer, indicating inadequate pain control.
- Addressing the **underlying cause** of her distress, which is severe pain, with appropriate analgesia is the immediate and most ethical first step in palliative care.
*Consult with the local ethics committee*
- While ethical considerations are paramount in end-of-life care, this is not the **initial action** as the patient's pain, a modifiable factor, needs to be addressed first.
- An ethics committee consultation would be more appropriate if adequate pain control has been attempted and the patient's request persists or if there are complex ethical dilemmas beyond immediate symptom management.
*Submit a referral to psychiatry*
- Although patients with severe illness may experience depression, the primary stated reason for her request is **unbearable pain**, which is a physical symptom requiring immediate medical attention.
- A psychiatric referral might be warranted if, after adequate pain management, the patient continues to express persistent desires for death or exhibits symptoms of a treatable mood disorder, but it is not the *initial* step.
*Submit a referral to hospice care*
- This is an appropriate step for a patient with metastatic colon cancer and frailty, as hospice provides **comprehensive palliative care**.
- However, the **immediate priority** is addressing her acute and inadequately treated pain, which is the stated reason for her distress and request for assistance in dying.
*Initiate authorization of physician-assisted suicide*
- Physician-assisted suicide is **illegal** in most jurisdictions and ethically controversial, and palliative care principles prioritize relieving suffering rather than ending life.
- The patient's request stems from **unmanaged pain**, which is a treatable condition, making physician-assisted suicide an inappropriate and premature consideration.
Question 177: A 34-year-old woman comes to the physician with fever and malaise. For the past 2 days, she has felt fatigued and weak and has had chills. Last night, she had a temperature of 40.8°C (104.2°F). She has also had difficulty swallowing since this morning. The patient was recently diagnosed with Graves disease and started on methimazole. She appears uncomfortable. Her temperature is 38.3°C (100.9°F), pulse is 95/min, and blood pressure is 134/74 mm Hg. The oropharynx is erythematous without exudate. The lungs are clear to auscultation. Laboratory studies show:
Hematocrit 42%
Hemoglobin 13.4 g/dL
Leukocyte count 3,200/mm3
Segmented neutrophils 9%
Basophils < 1%
Eosinophils < 1%
Lymphocytes 79%
Monocytes 11%
Platelet count 230,000/mm3
Which of the following is the most appropriate next step in management?
A. Decrease methimazole dose
B. Discontinue methimazole (Correct Answer)
C. Switch to propylthiouracil
D. Test for EBV, HIV, and CMV
E. Bone marrow biopsy
Explanation: ***Discontinue methimazole***
- The patient's symptoms (fever, chills, sore throat, malaise) and laboratory findings (**leukopenia with severe neutropenia**, specifically only 9% segmented neutrophils leading to an absolute neutrophil count of 288/mm³) are highly concerning for **agranulocytosis**, a rare but serious side effect of methimazole.
- **Agranulocytosis** is a life-threatening condition requiring immediate cessation of the offending drug to prevent severe infection and sepsis.
*Decrease methimazole dose*
- Reducing the dose is insufficient when **agranulocytosis** is suspected, as this condition warrants complete and immediate withdrawal of the drug.
- Even low doses of methimazole can trigger or sustain **agranulocytosis** in susceptible individuals.
*Switch to propylthiouracil*
- Propylthiouracil (PTU) is another **thionamide** and carries a similar risk of inducing **agranulocytosis**, albeit potentially at a lower rate than methimazole.
- Switching to another drug from the same class would not mitigate the risk and could exacerbate the current critical condition.
*Test for EBV, HIV, and CMV*
- While these viral infections can cause leukopenia, the acute onset of severe neutropenia in a patient recently started on **methimazole** makes drug-induced agranulocytosis the primary concern.
- Investigating these viral causes would delay critical intervention for a more immediate and life-threatening drug reaction.
*Bone marrow biopsy*
- A bone marrow biopsy might confirm the diagnosis of **agranulocytosis** by showing myeloid hypoplasia or aplasia, but it is not the *most appropriate initial step*.
- The immediate priority is to remove the suspected causative agent (methimazole) due to the high risk of infection associated with profound neutropenia.
Question 178: A 24-year-old man is taken to the emergency department by local law enforcement after they witnessed him physically assaulting a complete stranger. The officers report that they saw his eyes “moving back and forth quickly” and noted that he was very red-faced. The patient has no significant past medical or psychiatric history. His vital signs include: temperature 38.0°C (100.4°F), blood pressure 110/70 mm Hg, pulse 102/min, and respiratory rate 25/min. On physical examination, the patient is belligerent and refuses to cooperate during the examination. Rotary nystagmus is noted. Which of the following drugs would most likely be present in a urine toxicology screen from this patient?
A. Cocaine
B. Methamphetamine
C. Phencyclidine hydrochloride (PCP) (Correct Answer)
D. Lysergic acid diethylamide (LSD)
E. Marijuana
Explanation: ***Phencyclidine hydrochloride (PCP)***
- The patient's presentation with **belligerence**, **aggressiveness**, abnormal vital signs (tachycardia, tachypnea), and especially **rotary nystagmus** are classic signs of PCP intoxication.
- PCP is known to cause severe behavioral disturbances, including unprovoked violence, along with characteristic neurological signs like nystagmus.
*Cocaine*
- While cocaine can cause **agitation**, **tachycardia**, and **hypertension**, it is less commonly associated with the severe **belligerence** and **rotary nystagmus** seen in this patient.
- Cocaine intoxication typically presents with mydriasis, paranoia, and increased energy, but not typically the specific eye movements observed.
*Methamphetamine*
- Methamphetamine causes significant **sympathetic activation** leading to paranoia, **psychosis**, and agitation, similar to cocaine.
- However, the presence of **rotary nystagmus** is not a characteristic feature of methamphetamine intoxication.
*Lysergic acid diethylamide (LSD)*
- LSD primarily causes **hallucinations**, perceptual distortions, and altered thought processes, often leading to **panic attacks** or a "bad trip."
- It does not typically induce the severe **belligerence**, aggression, and **rotary nystagmus** described.
*Marijuana*
- Marijuana typically causes **euphoria**, relaxation, altered perception of time, and impaired motor coordination.
- It does not cause the profound agitation, **belligerence**, or **rotary nystagmus** seen in this clinical scenario.
Question 179: You are called to the bedside of a 75-year-old woman, who is post-op day 4 from a right total hip replacement. The patient appears agitated; she is trying to pull out her IV, and for the past 4 hours she has been accusing the nursing staff of trying to poison her. Her family notes that this behavior is completely different from her baseline; she has not shown any signs of memory loss or behavioral changes at home prior to the surgery. You note that she still has an indwelling catheter. She continues on an opioid-based pain regimen. All of the following are potential contributors to the patient’s presentation EXCEPT:
A. Volume depletion
B. Infection
C. Electrolyte abnormalities
D. Amyloid accumulation (Correct Answer)
E. Polypharmacy
Explanation: ***Amyloid accumulation***
- **Amyloid accumulation** is associated with **Alzheimer's disease** and other forms of **dementia**, which are chronic neurodegenerative conditions.
- The patient's acute onset of confusion and agitation, despite no prior history of cognitive decline, makes **amyloid accumulation** an unlikely immediate contributor to her current presentation.
*Volume depletion*
- **Dehydration** or **hypovolemia** can lead to reduced cerebral perfusion, altered mental status, and delirium in elderly patients.
- Post-operative patients, especially those with pain and limited mobility, are at increased risk for **volume depletion** if fluid intake is inadequate or fluid losses are excessive.
*Infection*
- **Urinary tract infections (UTIs)** are common in elderly patients, particularly those with indwelling catheters, and can present as acute delirium or altered mental status without typical fever or dysuria.
- The presence of an **indwelling catheter** makes a UTI a strong possibility for precipitating delirium in this patient.
*Electrolyte abnormalities*
- Disturbances in **electrolytes**, such as **hyponatremia** or **hypernatremia**, **hypokalemia**, or **hypercalcemia**, can profoundly affect brain function and lead to acute confusion, agitation, and delirium.
- Post-operative fluid shifts, medication effects, and underlying medical conditions can predispose elderly patients to **electrolyte imbalances**.
*Polypharmacy*
- The use of multiple medications, particularly sedatives, analgesics (like **opioids**), and anticholinergics, is a significant risk factor for **delirium** in older adults.
- Her current **opioid-based pain regimen** contributes to **polypharmacy** and poses a risk for drug-induced delirium.
Question 180: A 19-year-old woman comes to the physician because of increased sweating for the past 6 months. She experiences severe sweating that is triggered by stressful situations and speaking in public. She is failing one of her university classes because of her avoidance of public speaking. She has not had any fevers, chills, weight loss, or night sweats. Her temperature is 36.6°C (98°F). Physical examination shows moist skin in the axillae and on the palms, soles, and face. Which of the following drugs is most likely to be effective for this patient's condition?
A. Glycopyrrolate (Correct Answer)
B. Oxytocin
C. Physostigmine
D. Phenylephrine
E. Pilocarpine
Explanation: ***Glycopyrrolate***
- This patient presents with **primary focal hyperhidrosis**, characterized by excessive sweating without an underlying secondary cause, triggered by stress.
- **Eccrine sweat glands** are under **cholinergic (muscarinic) control** via sympathetic postganglionic fibers that release acetylcholine.
- **Glycopyrrolate** is an **anticholinergic drug** that works by blocking muscarinic receptors on sweat glands, thereby reducing sweat production.
- It is particularly effective for **focal hyperhidrosis** affecting palms, soles, and axillae.
*Oxytocin*
- **Oxytocin** is a hormone primarily involved in **social bonding**, labor induction, and milk ejection.
- It has no direct role in the regulation of sweat production or the treatment of hyperhidrosis.
*Physostigmine*
- **Physostigmine** is an **acetylcholinesterase inhibitor** that increases acetylcholine levels.
- This would exacerbate sweating, as acetylcholine stimulates muscarinic receptors on sweat glands, leading to increased perspiration.
*Phenylephrine*
- **Phenylephrine** is an **α1-adrenergic agonist** primarily used as a vasoconstrictor and decongestant.
- It acts on adrenergic receptors and does not directly affect the cholinergic pathways that control sweat gland activity.
*Pilocarpine*
- **Pilocarpine** is a **muscarinic agonist** that directly stimulates muscarinic receptors.
- This would significantly increase sweating and salivation, making it unsuitable for treating hyperhidrosis.