A 70-year-old woman with history of coronary artery disease status-post coronary artery bypass graft presents with a stroke due to an infarction in the right middle cerebral artery territory. She is admitted to the intensive care unit for neurological monitoring following a successful thrombectomy. Overnight, the patient complains of difficulty breathing, chest pain, and jaw pain. Her temperature is 98.6°F (37°C), blood pressure is 160/80 mmHg, pulse is 100/min, respirations are 30/min, and oxygen saturation is 90% on 2L O2 via nasal cannula. Rales are heard in the lower lung bases. Electrocardiogram reveals left ventricular hypertrophy with repolarization but no acute ST or T wave changes. Troponin is 2.8 ng/mL. Chest radiograph reveals Kerley B lines. After administration of oxygen, aspirin, carvedilol, and furosemide, the patient improves. The next troponin is 3.9 ng/mL. Upon further discussion with the consulting cardiologist and neurologist, a heparin infusion is started. After transfer to a general medicine ward floor four days later, the patient complains of a headache. The patient's laboratory results are notable for the following:
Hemoglobin: 11 g/dL
Hematocrit: 36%
Leukocyte count: 11,000 /mm^3 with normal differential
Platelet count: 130,000 /mm^3
On admission, the patient's platelet count was 300,000/mm^3. What medication is appropriate at this time?
Q522
A 26-year-old man comes to the physician because of a 1-week history of left-sided chest pain. The pain is worse when he takes deep breaths. Over the past 6 weeks, he had been training daily for an upcoming hockey tournament. He does not smoke cigarettes or drink alcohol but has used cocaine once. His temperature is 37.1°C (98.7°F), pulse is 75/min, and blood pressure is 128/85 mm Hg. Physical examination shows tenderness to palpation of the left chest. An x-ray of the chest is shown. Which of the following is the most appropriate initial pharmacotherapy?
Q523
A 55-year-old man presents to the emergency department with shortness of breath and weakness. Past medical history includes coronary artery disease, arterial hypertension, and chronic heart failure. He reports that the symptoms started around 2 weeks ago and have been gradually worsening. His temperature is 36.5°C (97.7°F), blood pressure is 135/90 mm Hg, heart rate is 95/min, respiratory rate is 24/min, and oxygen saturation is 94% on room air. On examination, mild jugular venous distention is noted. Auscultation reveals bilateral loud crackles. Pitting edema of the lower extremities is noted symmetrically. His plasma brain natriuretic peptide level on rapid bedside assay is 500 pg/mL (reference range < 125 pg/mL). A chest X-ray shows enlarged cardiac silhouette. He is diagnosed with acute on chronic left heart failure with pulmonary edema and receives immediate care with furosemide. The physician proposes a drug trial with a new BNP stabilizing agent. Which of the following changes below are expected to happen if the patient is enrolled in this trial?
Q524
A 13-year-old boy is brought to the emergency room by his mother for a generalized tonic-clonic seizure that occurred while attending a laser light show. His mother says that he has been otherwise healthy but “he often daydreams”. Over the past several months, he has reported recurrent episodes of jerky movements of his fingers and arms. These episodes usually occurred shortly after waking up in the morning. He has not lost consciousness during these episodes. Which of the following is the most appropriate treatment for this patient's condition?
Q525
A 25-year-old G1P1 with a history of diabetes and epilepsy gives birth to a female infant at 32 weeks gestation. The mother had no prenatal care and took no prenatal vitamins. The child's temperature is 98.6°F (37°C), blood pressure is 100/70 mmHg, pulse is 130/min, and respirations are 25/min. On physical examination in the delivery room, the child's skin is pink throughout and she cries on stimulation. All four extremities are moving spontaneously. A tuft of hair is found overlying the infant's lumbosacral region. Which of the following medications was this patient most likely taking during her pregnancy?
Q526
A 50-year-old man presents to the office with the complaint of pain in his left great toe. The pain started 2 days ago and has been progressively getting worse to the point that it is difficult to walk even a few steps. He adds that his left big toe is swollen and hot to the touch. He has never had similar symptoms in the past. He normally drinks 2–3 cans of beer every night but recently binge drank 3 nights ago. Physical examination is notable for an overweight gentleman (BMI of 35) in moderate pain, with an erythematous, swollen, and exquisitely tender left great toe. Laboratory results reveal a uric acid level of 9 mg/dL. A complete blood count shows:
Hemoglobin % 12 gm/dL
Hematocrit 45%
Mean corpuscular volume (MCV) 90 fL
Platelets 160,000/mm3
Leukocytes 8,000/mm3
Segmented neutrophils 65%
Lymphocytes 25%
Eosinophils 3%
Monocytes 7%
RBCs 5.6 million/mm3
Synovial fluid analysis shows:
Cell count 55,000 cells/mm3 (80% neutrophils)
Crystals negatively birefringent crystals present
Culture pending
Gram stain no organisms seen
Which of the following is the mechanism of action of the drug that will most likely be used in the long-term management of this patient?
Q527
A 55-year-old man comes to the physician because of a 4-month history of fatigue, increased sweating, and a 5.4-kg (12-lb) weight loss. Over the past 3 weeks, he has had gingival bleeding when brushing his teeth. Twenty years ago, he was diagnosed with a testicular tumor and treated with radiation therapy. His temperature is 37.8°C (100°F), pulse is 70/min, respirations are 12/min, and blood pressure is 130/80 mm Hg. He takes no medications. Cardiopulmonary examination shows no abnormalities. The spleen is palpated 4 cm below the left costal margin. Laboratory studies show:
Hemoglobin 9 g/dL
Mean corpuscular volume 86 μm3
Leukocyte count 110,000/mm3
Segmented neutrophils 24%
Metamyelocytes 6%
Myelocytes 34%
Promyelocytes 14%
Blasts 1%
Lymphocytes 11%
Monocytes 4%
Eosinophils 4%
Basophils 2%
Platelet count 650,000/mm3
Molecular testing confirms the diagnosis. Which of the following is the most appropriate next step in treatment?
Q528
A 72-year-old woman with a history of atrial fibrillation on warfarin, diabetes, seizure disorder and recent MRSA infection is admitted to the hospital. She subsequently begins therapy with another drug and is found to have a supratherapeutic International Normalized Ratio (INR). Which of the following drugs is likely contributing to this patient's elevated INR?
Q529
A 42-year-old man presents to his family physician for evaluation of oral pain. He states that he has increasing pain in a molar on the top left of his mouth. The pain started 1 week ago and has been progressively worsening since then. His medical history is significant for hypertension and type 2 diabetes mellitus, both of which are currently controlled with lifestyle modifications. His blood pressure is 124/86 mm Hg, heart rate is 86/min, and respiratory rate is 14/min. Physical examination is notable for a yellow-black discoloration of the second molar on his left upper mouth. The decision is made to refer him to a dentist for further management of this cavity. The patient has never had any dental procedures and is nervous about what type of sedation will be used. Which of the following forms of anesthesia utilizes solely an oral or intravenous anti-anxiety medication?
Q530
A 23-year-old male presents with complaints of polydipsia and frequent, large-volume urination. Laboratory testing does not demonstrate any evidence of diabetes; however, a reduced urine osmolality of 120 mOsm/L is measured. Which of the following findings on a desmopressin test would be most consistent with a diagnosis of central diabetes insipidus?
Autonomic/CV Drugs US Medical PG Practice Questions and MCQs
Question 521: A 70-year-old woman with history of coronary artery disease status-post coronary artery bypass graft presents with a stroke due to an infarction in the right middle cerebral artery territory. She is admitted to the intensive care unit for neurological monitoring following a successful thrombectomy. Overnight, the patient complains of difficulty breathing, chest pain, and jaw pain. Her temperature is 98.6°F (37°C), blood pressure is 160/80 mmHg, pulse is 100/min, respirations are 30/min, and oxygen saturation is 90% on 2L O2 via nasal cannula. Rales are heard in the lower lung bases. Electrocardiogram reveals left ventricular hypertrophy with repolarization but no acute ST or T wave changes. Troponin is 2.8 ng/mL. Chest radiograph reveals Kerley B lines. After administration of oxygen, aspirin, carvedilol, and furosemide, the patient improves. The next troponin is 3.9 ng/mL. Upon further discussion with the consulting cardiologist and neurologist, a heparin infusion is started. After transfer to a general medicine ward floor four days later, the patient complains of a headache. The patient's laboratory results are notable for the following:
Hemoglobin: 11 g/dL
Hematocrit: 36%
Leukocyte count: 11,000 /mm^3 with normal differential
Platelet count: 130,000 /mm^3
On admission, the patient's platelet count was 300,000/mm^3. What medication is appropriate at this time?
A. Enoxaparin
B. Argatroban (Correct Answer)
C. Protamine
D. Dalteparin
E. Tinzaparin
Explanation: ***Argatroban***
- This patient presents with a **new headache** and a significant drop in **platelet count** (from 300,000 to 130,000 /mm^3) while on **heparin**, which is highly suggestive of **heparin-induced thrombocytopenia (HIT)**. Argatroban is a **direct thrombin inhibitor** and is the preferred anticoagulant in patients with HIT, especially those with renal insufficiency.
- HIT is a prothrombotic disorder, and immediate cessation of heparin and initiation of a non-heparin anticoagulant like argatroban is crucial to prevent life-threatening thrombotic complications.
*Enoxaparin*
- **Enoxaparin** is a **low molecular weight heparin (LMWH)**. All heparins, including LMWH and unfractionated heparin, are contraindicated in HIT because they can cross-react with antibodies formed against the heparin-platelet factor 4 complex, exacerbating the condition.
- Using enoxaparin would worsen the patient's HIT and increase the risk of thrombosis.
*Protamine*
- **Protamine sulfate** is used to **reverse the anticoagulant effects of heparin** by binding to it.
- While it reverses heparin, it does not address the underlying **prothrombotic state** of HIT and would not be an appropriate anticoagulant to use.
*Dalteparin*
- **Dalteparin** is another **low molecular weight heparin (LMWH)**. Similar to enoxaparin, all heparins are contraindicated in **heparin-induced thrombocytopenia (HIT)**.
- Using dalteparin could still trigger platelet activation and thrombosis in a patient with HIT.
*Tinzaparin*
- **Tinzaparin** is also a **low molecular weight heparin (LMWH)**. As with other heparins, it should be avoided in patients with **heparin-induced thrombocytopenia (HIT)**.
- Continuing any form of heparin would perpetuate the immune response and the risk of new thrombotic events.
Question 522: A 26-year-old man comes to the physician because of a 1-week history of left-sided chest pain. The pain is worse when he takes deep breaths. Over the past 6 weeks, he had been training daily for an upcoming hockey tournament. He does not smoke cigarettes or drink alcohol but has used cocaine once. His temperature is 37.1°C (98.7°F), pulse is 75/min, and blood pressure is 128/85 mm Hg. Physical examination shows tenderness to palpation of the left chest. An x-ray of the chest is shown. Which of the following is the most appropriate initial pharmacotherapy?
A. Heparin
B. Nitroglycerin
C. Alteplase
D. Naproxen (Correct Answer)
E. Alprazolam
Explanation: ***Naproxen***
- This patient presents with symptoms highly suggestive of **costochondritis** or a **musculoskeletal chest wall pain**. Key features include **tenderness to palpation of the chest wall**, pain made worse by **deep breaths** (pleuritic nature), and a history of strenuous activity (hockey training).
- An X-ray of the chest appears normal, ruling out other serious causes of chest pain like pneumothorax or significant infiltrates. Given the musculoskeletal nature of the pain, a **nonsteroidal anti-inflammatory drug (NSAID)** like naproxen is the most appropriate initial treatment to reduce pain and inflammation.
*Heparin*
- Heparin is an **anticoagulant** used to treat or prevent blood clots, such as in **pulmonary embolism** or deep vein thrombosis.
- While chest pain can be a symptom of pulmonary embolism, the physical exam finding of **localized tenderness to palpation** is not characteristic of a pulmonary embolism, and the normal chest X-ray makes it less likely.
*Nitroglycerin*
- Nitroglycerin is primarily used to treat **angina pectoris** (chest pain due to reduced blood flow to the heart) by causing vasodilation and reducing cardiac workload.
- The patient's age (26), absence of typical cardiac risk factors (except for prior cocaine use, which can cause vasospasm but is not suggested by the clinical picture or exam), and the **pleuritic nature of the pain** with **chest wall tenderness** make angina unlikely.
*Alteplase*
- Alteplase is a **thrombolytic agent** used to dissolve existing blood clots, typically in conditions like **acute myocardial infarction**, **pulmonary embolism**, or **ischemic stroke**.
- There is no clinical or radiological evidence (normal chest X-ray) to suggest a life-threatening thrombotic event requiring thrombolysis in this patient.
*Alprazolam*
- Alprazolam is a **benzodiazepine** used to treat **anxiety and panic disorders**.
- While anxiety can sometimes manifest as chest pain, the clear physical finding of **localized chest wall tenderness** points to a physical cause, and thus, an anxiolytic is not the most appropriate initial pharmacotherapy.
Question 523: A 55-year-old man presents to the emergency department with shortness of breath and weakness. Past medical history includes coronary artery disease, arterial hypertension, and chronic heart failure. He reports that the symptoms started around 2 weeks ago and have been gradually worsening. His temperature is 36.5°C (97.7°F), blood pressure is 135/90 mm Hg, heart rate is 95/min, respiratory rate is 24/min, and oxygen saturation is 94% on room air. On examination, mild jugular venous distention is noted. Auscultation reveals bilateral loud crackles. Pitting edema of the lower extremities is noted symmetrically. His plasma brain natriuretic peptide level on rapid bedside assay is 500 pg/mL (reference range < 125 pg/mL). A chest X-ray shows enlarged cardiac silhouette. He is diagnosed with acute on chronic left heart failure with pulmonary edema and receives immediate care with furosemide. The physician proposes a drug trial with a new BNP stabilizing agent. Which of the following changes below are expected to happen if the patient is enrolled in this trial?
A. Increased potassium release from cardiomyocytes
B. Increased water reabsorption by the renal collecting ducts
C. Increased blood pressure
D. Inhibition of funny sodium channels
E. Restricted aldosterone release (Correct Answer)
Explanation: ***Restricted aldosterone release***
- **BNP** acts to counter the **RAAS** system. By stabilizing BNP, there will be increased **natriuresis** and reduced levels of aldosterone due to its inhibitory effect on **renin secretion**.
- This **aldosterone** restriction contributes to **diuresis** and vasodilation, which ultimately helps to reduce cardiac preload and afterload.
*Increased potassium release from cardiomyocytes*
- An increase in **potassium release** from cardiomyocytes is not a direct or expected effect of a **BNP stabilizing agent**.
- BNP primarily influences **sodium** and **water balance** through renal and vascular effects, not direct cardiomyocyte potassium regulation.
*Increased water reabsorption by the renal collecting ducts*
- **BNP** promotes **natriuresis** and **diuresis**, leading to decreased water reabsorption in the renal collecting ducts.
- A BNP stabilizing agent would therefore **decrease water reabsorption**, working against the action of **ADH**.
*Increased blood pressure*
- **BNP** acts as a **vasodilator** and promotes fluid excretion, which typically leads to a **reduction** in blood pressure.
- Stabilizing BNP would therefore be expected to maintain or reduce **blood pressure**, not increase it.
*Inhibition of funny sodium channels*
- **Funny channels** (If channels) are primarily found in the **pacemaker cells** of the heart and are involved in controlling heart rate.
- While BNP can influence heart rate indirectly, its primary mechanism of action does not involve direct **inhibition of funny sodium channels**.
Question 524: A 13-year-old boy is brought to the emergency room by his mother for a generalized tonic-clonic seizure that occurred while attending a laser light show. His mother says that he has been otherwise healthy but “he often daydreams”. Over the past several months, he has reported recurrent episodes of jerky movements of his fingers and arms. These episodes usually occurred shortly after waking up in the morning. He has not lost consciousness during these episodes. Which of the following is the most appropriate treatment for this patient's condition?
A. Carbamazepine
B. Tiagabine
C. Vigabatrin
D. Diazepam
E. Valproate (Correct Answer)
Explanation: ***Valproate***
- This patient presents with symptoms characteristic of **juvenile myoclonic epilepsy (JME)** including **myoclonic jerks** upon awakening, **absences** ("daydreaming"), and generalized tonic-clonic seizures, especially those triggered by **photic stimulation** (laser light show).
- **Valproate** is considered the first-line and most effective treatment for JME, offering broad-spectrum efficacy against all seizure types seen in this syndrome.
*Carbamazepine*
- **Carbamazepine** is primarily used for **focal seizures** and **generalized tonic-clonic seizures** that are not associated with myoclonus or absence seizures.
- It can potentially **exacerbate myoclonic and absence seizures** in patients with JME, making it an inappropriate choice.
*Tiagabine*
- **Tiagabine** is an **adjunctive treatment** for **focal onset seizures** and works by inhibiting GABA reuptake.
- It is **not effective** for generalized seizure types like those seen in JME and can even worsen them.
*Vigabatrin*
- **Vigabatrin** is an **irreversible inhibitor of GABA transaminase** used primarily for **infantile spasms** and refractory focal seizures.
- Its use is limited by a high risk of **permanent ophthalmic damage** (retinal toxicity), making it unsuitable for JME.
*Diazepam*
- **Diazepam** is a **fast-acting benzodiazepine** primarily used for the **acute termination of seizures**, particularly status epilepticus.
- It is not a suitable long-term maintenance treatment for epilepsy due to issues like **tolerance** and **sedation**.
Question 525: A 25-year-old G1P1 with a history of diabetes and epilepsy gives birth to a female infant at 32 weeks gestation. The mother had no prenatal care and took no prenatal vitamins. The child's temperature is 98.6°F (37°C), blood pressure is 100/70 mmHg, pulse is 130/min, and respirations are 25/min. On physical examination in the delivery room, the child's skin is pink throughout and she cries on stimulation. All four extremities are moving spontaneously. A tuft of hair is found overlying the infant's lumbosacral region. Which of the following medications was this patient most likely taking during her pregnancy?
A. Valproic acid (Correct Answer)
B. Warfarin
C. Gentamicin
D. Lithium
E. Ethosuximide
Explanation: ***Valproic acid***
- The presence of a **tuft of hair over the lumbosacral region** strongly suggests an underlying **neural tube defect**, such as spina bifida.
- **Valproic acid** is an antiepileptic drug known for its significant association with an increased risk of neural tube defects when taken during pregnancy, especially in the first trimester.
*Warfarin*
- **Warfarin** is a known teratogen associated with **fetal warfarin syndrome**, characterized by bone abnormalities (e.g., nasal hypoplasia, stippled epiphyses), not primarily neural tube defects.
- It works as a **vitamin K antagonist** and causes bleeding if taken during pregnancy.
*Gentamicin*
- **Gentamicin** is an aminoglycoside antibiotic primarily associated with **ototoxicity** (hearing loss) and **nephrotoxicity** in the fetus.
- It is not known to cause neural tube defects.
*Lithium*
- **Lithium** is a mood stabilizer linked to **Ebstein's anomaly**, a congenital heart defect affecting the tricuspid valve, when taken during pregnancy.
- It is not associated with neural tube defects.
*Ethosuximide*
- **Ethosuximide** is an antiepileptic drug primarily used for absence seizures.
- While all antiepileptic drugs carry some teratogenic risk, ethosuximide has a lower risk of neural tube defects compared to valproic acid.
Question 526: A 50-year-old man presents to the office with the complaint of pain in his left great toe. The pain started 2 days ago and has been progressively getting worse to the point that it is difficult to walk even a few steps. He adds that his left big toe is swollen and hot to the touch. He has never had similar symptoms in the past. He normally drinks 2–3 cans of beer every night but recently binge drank 3 nights ago. Physical examination is notable for an overweight gentleman (BMI of 35) in moderate pain, with an erythematous, swollen, and exquisitely tender left great toe. Laboratory results reveal a uric acid level of 9 mg/dL. A complete blood count shows:
Hemoglobin % 12 gm/dL
Hematocrit 45%
Mean corpuscular volume (MCV) 90 fL
Platelets 160,000/mm3
Leukocytes 8,000/mm3
Segmented neutrophils 65%
Lymphocytes 25%
Eosinophils 3%
Monocytes 7%
RBCs 5.6 million/mm3
Synovial fluid analysis shows:
Cell count 55,000 cells/mm3 (80% neutrophils)
Crystals negatively birefringent crystals present
Culture pending
Gram stain no organisms seen
Which of the following is the mechanism of action of the drug that will most likely be used in the long-term management of this patient?
A. Activates adenosine monophosphate (AMP) deaminase
B. Inhibits renal clearance of uric acid
C. Activates inosine monophosphate (IMP) dehydrogenase
D. Inhibits xanthine oxidase (Correct Answer)
E. Increases renal clearance of uric acid
Explanation: ***Inhibits xanthine oxidase***
- The patient's symptoms (acute, severe pain in the **great toe**, swelling, erythema, elevated **uric acid** 9 mg/dL, and presence of **negatively birefringent crystals** in synovial fluid) are classic for an acute **gout attack**.
- **Allopurinol** and **febuxostat** are long-term management drugs that work by inhibiting **xanthine oxidase**, an enzyme crucial for uric acid production, thereby reducing serum uric acid levels and preventing future attacks.
*Activates adenosine monophosphate (AMP) deaminase*
- This is not a mechanism of action for common long-term gout medications. AMP deaminase is involved in purine metabolism but is not a direct target for uric acid lowering.
- Manipulating AMP deaminase activity is not a recognized therapeutic approach for chronic gout management.
*Inhibits renal clearance of uric acid*
- This mechanism would *increase* serum uric acid levels, which is contraindicated in the long-term management of gout.
- Drugs that inhibit renal clearance of uric acid would exacerbate the condition, leading to more frequent and severe gout attacks.
*Activates inosine monophosphate (IMP) dehydrogenase*
- This is not a mechanism of action for long-term gout medications. IMP dehydrogenase is involved in de novo purine synthesis.
- Inhibitors of IMP dehydrogenase, like **mycophenolate mofetil**, are used in transplant medicine and autoimmune conditions, not for lowering uric acid.
*Increases renal clearance of uric acid*
- Drugs like **probenecid** act as **uricosurics** by increasing the renal excretion of uric acid. While this helps lower uric acid, it is specifically contraindicated in patients with **renal stones** or impaired renal function due to the risk of stone formation.
- **Uricosurics** are generally second-line agents for long-term management in patients who **under-excrete uric acid** and have good renal function.
Question 527: A 55-year-old man comes to the physician because of a 4-month history of fatigue, increased sweating, and a 5.4-kg (12-lb) weight loss. Over the past 3 weeks, he has had gingival bleeding when brushing his teeth. Twenty years ago, he was diagnosed with a testicular tumor and treated with radiation therapy. His temperature is 37.8°C (100°F), pulse is 70/min, respirations are 12/min, and blood pressure is 130/80 mm Hg. He takes no medications. Cardiopulmonary examination shows no abnormalities. The spleen is palpated 4 cm below the left costal margin. Laboratory studies show:
Hemoglobin 9 g/dL
Mean corpuscular volume 86 μm3
Leukocyte count 110,000/mm3
Segmented neutrophils 24%
Metamyelocytes 6%
Myelocytes 34%
Promyelocytes 14%
Blasts 1%
Lymphocytes 11%
Monocytes 4%
Eosinophils 4%
Basophils 2%
Platelet count 650,000/mm3
Molecular testing confirms the diagnosis. Which of the following is the most appropriate next step in treatment?
A. Phlebotomy
B. Cytarabine and daunorubicin therapy
C. Rituximab therapy
D. Low-dose aspirin therapy
E. Imatinib therapy (Correct Answer)
Explanation: ***Imatinib therapy***
- The patient's presentation with **fatigue**, **sweating**, **weight loss**, **gingival bleeding**, **splenomegaly**, and remarkable lab findings (**leukocytosis** with a left shift including **myelocytes**, **promyelocytes**, low blast count, **thrombocytosis**, and **anemia**) is highly suggestive of **Chronic Myeloid Leukemia (CML)**.
- Molecular testing would confirm the presence of the **Philadelphia chromosome (BCR-ABL1 fusion gene)**, which is the target of **imatinib**, a tyrosine kinase inhibitor (TKI) and the first-line treatment for CML.
*Phlebotomy*
- **Phlebotomy** is a treatment for **polycythemia vera**, a myeloproliferative neoplasm characterized by an *elevated red blood cell count*, which is not present here (patient has anemia).
- It aims to reduce blood viscosity and iron overload, which are not the primary issues in this patient.
*Cytarabine and daunorubicin therapy*
- This combination therapy (often termed "7+3" regimen) is standard induction chemotherapy for **Acute Myeloid Leukemia (AML)**.
- The patient's **low blast count (1%)** and presence of various myeloid precursor stages define a chronic phase of a myeloproliferative neoplasm, not acute leukemia (which requires >20% blasts).
*Rituximab therapy*
- **Rituximab** is a monoclonal antibody that targets the **CD20 antigen** found on B-cells and is primarily used in the treatment of **B-cell non-Hodgkin lymphomas** and **Chronic Lymphocytic Leukemia (CLL)**.
- This patient presents with a myeloid proliferation, not a lymphoid malignancy.
*Low-dose aspirin therapy*
- **Low-dose aspirin** is used for its antiplatelet effects to prevent thrombotic events, particularly in conditions like **essential thrombocythemia** or **polycythemia vera** where platelet counts or red cell mass are significantly elevated sometimes requiring aspirin if clots are forming.
- While this patient has thrombocytosis, treating the underlying CML with imatinib is the priority and will typically normalize platelet counts, making aspirin a secondary or adjunct consideration if thrombosis risk is high and CML treatment is not yet effective.
Question 528: A 72-year-old woman with a history of atrial fibrillation on warfarin, diabetes, seizure disorder and recent MRSA infection is admitted to the hospital. She subsequently begins therapy with another drug and is found to have a supratherapeutic International Normalized Ratio (INR). Which of the following drugs is likely contributing to this patient's elevated INR?
A. Carbamazepine
B. Phenobarbital
C. Glipizide
D. Rifampin
E. Valproic acid (Correct Answer)
Explanation: ***Valproic acid***
- **Valproic acid** inhibits the **CYP2C9** enzyme and can displace **warfarin** from **plasma protein binding sites**, increasing free warfarin levels and leading to a **supratherapeutic INR**.
- This interaction is particularly relevant in patients on warfarin, as it directly potentiates its anticoagulant effect.
*Carbamazepine*
- **Carbamazepine** is a potent **CYP450 enzyme inducer**, which would typically **decrease** warfarin levels and **lower** the INR.
- It would counteract the anticoagulant effect of warfarin, not enhance it.
*Phenobarbital*
- **Phenobarbital** is another strong **CYP450 enzyme inducer**, similar to carbamazepine.
- Its use would likely **reduce** the plasma concentration of warfarin, resulting in a **subtherapeutic INR**.
*Glipizide*
- **Glipizide** is an **oral hypoglycemic agent** and does not have a significant direct interaction with warfarin that would elevate the INR.
- While some sulfonylureas can have minor anticoagulant effects, they are not a primary cause of **supratherapeutic INR** in this context.
*Rifampin*
- **Rifampin** is a powerful **CYP450 enzyme inducer**, known to significantly **reduce** the effectiveness of many drugs, including warfarin.
- It would lead to a **lower** INR, increasing the risk of thrombotic events.
Question 529: A 42-year-old man presents to his family physician for evaluation of oral pain. He states that he has increasing pain in a molar on the top left of his mouth. The pain started 1 week ago and has been progressively worsening since then. His medical history is significant for hypertension and type 2 diabetes mellitus, both of which are currently controlled with lifestyle modifications. His blood pressure is 124/86 mm Hg, heart rate is 86/min, and respiratory rate is 14/min. Physical examination is notable for a yellow-black discoloration of the second molar on his left upper mouth. The decision is made to refer him to a dentist for further management of this cavity. The patient has never had any dental procedures and is nervous about what type of sedation will be used. Which of the following forms of anesthesia utilizes solely an oral or intravenous anti-anxiety medication?
A. Minimal Sedation (Correct Answer)
B. Dissociation
C. Regional anesthesia
D. Epidural anesthesia
E. Deep sedation
Explanation: ***Minimal Sedation***
- This involves using **oral** or **intravenous anti-anxiety medications** to help a patient relax while remaining conscious and responsive.
- The patient can still respond to verbal commands but is in a state of decreased anxiety and awareness.
*Dissociation*
- This is a state induced by certain drugs, like **ketamine**, where the patient feels detached from their body and environment.
- While it can be achieved intravenously, it is not solely an anti-anxiety medication effect and involves a different neurological state.
*Regional anesthesia*
- This involves injecting a **local anesthetic** near nerves to numb a specific part of the body, such as a limb or a jaw section for dental procedures.
- It primarily provides pain relief by blocking nerve signals and does not typically involve anti-anxiety medication as its sole component for sedation.
*Epidural anesthesia*
- This form of regional anesthesia involves injecting a **local anesthetic** into the **epidural space** surrounding the spinal cord to block pain signals.
- It is used for pain control during surgery or childbirth and does not involve oral or intravenous anti-anxiety medication as the primary method of sedation.
*Deep sedation*
- This involves a more profound depression of consciousness than minimal sedation, where the patient may be difficult to arouse but still responds purposefully to repeated or painful stimulation.
- While it can use intravenous medications, it typically involves a combination of sedatives and analgesics to achieve a deeper state of unresponsiveness, beyond just anti-anxiety medication.
Question 530: A 23-year-old male presents with complaints of polydipsia and frequent, large-volume urination. Laboratory testing does not demonstrate any evidence of diabetes; however, a reduced urine osmolality of 120 mOsm/L is measured. Which of the following findings on a desmopressin test would be most consistent with a diagnosis of central diabetes insipidus?
A. Reduction in urine osmolality to 60 mOsm/L following desmopressin administration
B. No detectable change in urine osmolality following desmopressin administration
C. Increase in urine osmolality to 400 mOsm/L following desmopressin administration (Correct Answer)
D. Increase in urine osmolality to 130 mOsm/L following desmopressin administration
E. Reduction in urine osmolality to 110 mOsm/L following desmopressin administration
Explanation: ***Increase in urine osmolality to 400 mOsm/L following desmopressin administration***
- In **central diabetes insipidus**, the kidneys are still able to respond to **vasopressin** (ADH), but the body doesn't produce enough of it. Therefore, administering **desmopressin** (a synthetic ADH analog) will significantly increase **urine osmolality** as the kidneys resorb more water.
- A significant increase, such as from 120 mOsm/L to 400 mOsm/L, indicates that the underlying problem is a lack of ADH production, characteristic of **central diabetes insipidus**.
*Increase in urine osmolality to 130 mOsm/L following desmopressin administration*
- A minor increase from 120 mOsm/L to 130 mOsm/L following desmopressin administration would suggest that the kidneys are largely **unresponsive** to ADH, which is characteristic of **nephrogenic diabetes insipidus**.
- In central diabetes insipidus, a more substantial increase in **urine osmolality** is expected, as the kidney's ability to respond to ADH is intact.
*Reduction in urine osmolality to 60 mOsm/L following desmopressin administration*
- A reduction in **urine osmolality** after desmopressin administration would be an unexpected and contradictory finding.
- Desmopressin is meant to increase water reabsorption, leading to concentrated urine, not more dilute urine.
*Reduction in urine osmolality to 110 mOsm/L following desmopressin administration*
- Similar to the previous option, a reduction in **urine osmolality** following desmopressin administration is clinically inconsistent with the expected action of ADH.
- This result would not align with either central nor nephrogenic diabetes insipidus scenarios, where an increase or no change, respectively, would be anticipated.
*No detectable change in urine osmolality following desmopressin administration*
- If there is no detectable change or only a very small change in **urine osmolality** after desmopressin administration, it suggests that the kidneys are not responding to ADH.
- This would be consistent with **nephrogenic diabetes insipidus**, where the kidneys themselves are resistant to ADH, rather than central DI, where the problem is ADH deficiency.
