A 59-year-old man presents to the emergency department with right-sided weakness and an inability to speak for the past 2 hours. His wife says he was gardening in his backyard when he suddenly lost balance and fell down. The patient has a past medical history of hypertension, diabetes mellitus, and coronary artery disease. Two years ago, he was admitted to the coronary intensive care unit with an anterolateral myocardial infarction. He has not been compliant with his medications since he was discharged. On physical examination, his blood pressure is 110/70 mm Hg, pulse is 110/min and irregular, temperature is 36.6°C (97.8°F), and respiratory rate is 18/min. Strength is 2/5 in both his right upper and right lower extremities. His right calf is edematous with visible varicose veins. Which of the following is the best method to detect the source of this patient’s stroke?
Q52
A 33-year-old man presents to the emergency department with severe anxiety. He has had multiple episodes in the past treated with low dose lorazepam. The patient states that he feels as if he is going to die and that he cannot breathe. His past medical history is notable for depression and anxiety. His temperature is 98.1°F (36.7°C), blood pressure is 122/83 mmHg, pulse is 153/min, respirations are 13/min, and oxygen saturation is 98% on room air. The patient is given a low dose of lorazepam and reports a complete resolution of his symptoms. An ECG is performed and demonstrates prolongation of the P-R interval. There is a P wave preceding every QRS complex, no dropped QRS complexes, and the P-R interval does not change. His initial lab values are unremarkable. Which of the following is the best management of this patient?
Q53
A 51-year-old man is brought to the local emergency room in severe respiratory distress. The patient is an industrial chemist and was working in his lab with a new partner when a massive chemical spill occurred releasing fumes into their workspace. The patient and his lab partner attempted to clean up the spill before they realized it was too large for them to handle. They were not wearing protective equipment at the time, except for a pair of goggles. The fumes caused them both to begin coughing; however, this patient has a history significant for asthma. His condition worsened, which prompted lab management to call for an ambulance. On arrival at the emergency room, the patient’s respiratory rate is 42/min and oxygen saturation is 96% on room air. He is unable to speak on account of his coughing. He is clearly using accessory muscles with inspiration. A pulmonary exam reveals bilateral wheezes. He is given multiple nebulizer treatments of albuterol and is started on intravenous (IV) methylprednisolone. After 2 successive nebulizer treatments, the arterial blood gas test result shows pH 7.36, partial pressure of carbon dioxide (PCO2) 41 mm Hg, and partial pressure of oxygen (PO2) 79 mm Hg. He is now able to speak and the respiratory rate is 32/min. Which of the following is the best next step in this patient’s management?
Q54
An 80-year-old woman presents to her cardiologist for a scheduled appointment. She was shown to have moderate atrial dilation on echocardiography 3 years ago and was started on oral medications. The patient insists that she does not want aggressive treatment because she wants her remaining years to be peaceful. She has not been compliant with her medications and declines further investigations. Her heart rate today is 124/min and irregular. Which of the following organs is least likely to be affected by complications of her condition if she declines further management?
Q55
A 22-year-old man is brought to the emergency department 25 minutes after an episode of violent jerky movements of his arms and legs. He has no recollection of the episode. The episode lasted for 3–4 minutes. His girlfriend reports that he has not been sleeping well over the past month. He is only oriented to place and person. His temperature is 37°C (98.6°F), pulse is 99/min, respirations are 18/min, and blood pressure is 110/80 mm Hg. Neurologic examination shows no focal findings. A complete blood count as well as serum concentrations of glucose, electrolytes, and calcium are within the reference range. Urine toxicology screening is negative. An MRI of the brain shows no abnormalities. Which of the following is the most appropriate next step in management?
Q56
A 67-year-old woman comes to the emergency department 1 hour after her husband saw her faint shortly after getting out of bed from a nap. She regained consciousness within 30 seconds and was fully alert and oriented. She has had 2 similar episodes in the last 5 years, once while standing in line at the grocery store and once when getting out of bed in the morning. 24-hour Holter monitoring and echocardiography were unremarkable at her last hospitalization 1 year ago. She has hypertension, depression, and asthma. Current medications include verapamil, nortriptyline, and an albuterol inhaler as needed. Her temperature is 37°C (98.4°F), pulse is 74/min and regular, respirations are 14/min, blood pressure is 114/72 mm Hg when supine and 95/60 mm Hg while standing. Cardiopulmonary examination shows no abnormalities. Neurologic examination shows no focal findings. A complete blood count and serum concentrations of electrolytes, urea nitrogen, creatinine, and glucose are within the reference range. Bedside cardiac monitoring shows rare premature ventricular contractions and T-wave inversions in lead III. Which of the following is the most likely cause of this patient's symptoms?
Q57
A 71-year-old female is brought to the emergency room by her husband. The husband reports that they were taking a walk together one hour ago, when his wife experienced sudden, right arm and leg weakness. He noticed that she had slurred speech, and that she was not able to tell him where she was. The patient underwent an emergent CT scan, which was unremarkable, and was treated with tissue plasminogen activator (tPA). Which of the following EKG findings increases a patient's risk for this acute presentation?
Q58
A 57-year-old man comes to the emergency department with fatigue and palpitations for several weeks. An ECG shows atrial fibrillation. Echocardiography shows thrombus formation in the left atrium. Which of the following organs is most likely to continue to function in the case of an embolic event?
Q59
A 22-year-old medical student presents to a community health center due to an episode of loss of consciousness 3 days ago. She also has a history of multiple episodes of dizziness in the last year. These episodes almost always occur when she is observing surgery in the operating room. She describes her dizziness as a feeling of lightheadedness, warmth, excessive sweating, and palpitations. She feels that she will fall down if she stood longer and usually sits on the floor or leaves the room until the feeling subsides. Three days ago, she collapsed while observing an open cholecystectomy but regained consciousness after a few seconds. Once she regained consciousness, she was pale and sweating excessively. Her medical history is significant for migraines, but she is not on prophylactic therapy. Her younger brother has cerebral palsy, and her uncle had a sudden death at the age of 25. Her blood pressure is 120/80 mm Hg when lying down and 118/80 mm Hg when in a standing position. The rest of the physical examination is within normal limits. What is the next best step in the management of this patient?
Q60
A 31-year-old woman with a history of anorexia nervosa diagnosed 2 years ago presents for follow up. She says that, although she feels some improvement with cognitive-behavioral therapy (CBT), she is still struggling with her body image and fears gaining weight. She says that for the past 3 weeks she has noticed her ankles are uncomfortably swollen in the mornings. She also mentions that she still is having intermittent menstruation; her last menstrual cycle was 4 months ago. The patient denies any suicidal ideations. She has no other significant past medical history. She denies any history of smoking, alcohol consumption, or recreational drug use. The patient’s vital signs include: temperature 37.0°C (98.6°F), pulse 55/min, blood pressure 100/69 mm Hg, and respiratory rate 18/min. Her body mass index (BMI) is 17.1 kg/m2, improved from 16.9 kg/m2, 6 months ago. Her physical examination is significant for an irregular heart rhythm on cardiopulmonary auscultation. There is also significant 3+ pitting edema in the lower extremities bilaterally. An ECG reveals multiple isolated premature ventricular contractions (PVCs) with 1 10-sec episode of bigeminy. Which of the following aspects of this patient’s history and physical examination would be the strongest indication for inpatient hospitalization?
Arrhythmias US Medical PG Practice Questions and MCQs
Question 51: A 59-year-old man presents to the emergency department with right-sided weakness and an inability to speak for the past 2 hours. His wife says he was gardening in his backyard when he suddenly lost balance and fell down. The patient has a past medical history of hypertension, diabetes mellitus, and coronary artery disease. Two years ago, he was admitted to the coronary intensive care unit with an anterolateral myocardial infarction. He has not been compliant with his medications since he was discharged. On physical examination, his blood pressure is 110/70 mm Hg, pulse is 110/min and irregular, temperature is 36.6°C (97.8°F), and respiratory rate is 18/min. Strength is 2/5 in both his right upper and right lower extremities. His right calf is edematous with visible varicose veins. Which of the following is the best method to detect the source of this patient’s stroke?
A. Carotid duplex
B. Head CT without contrast
C. V/Q scan of his lungs
D. ECG (Correct Answer)
E. Duplex ultrasound of his right leg
Explanation: ***ECG***
- The patient's presentation with **sudden focal neurological deficits** (right-sided weakness, inability to speak) points to an **acute ischemic stroke**. His **irregular pulse** and history of **anterolateral myocardial infarction** suggest a cardiac source for an embolism.
- An **ECG** can quickly identify **atrial fibrillation (Afib)**, a common cause of cardioembolic stroke due to thrombus formation in the left atrium, especially given his **irregular pulse** and history of cardiac disease.
*Carotid duplex*
- While **carotid artery stenosis** can cause ischemic stroke, it typically presents with a **carotid bruit** on examination and is often associated with transient ischemic attacks (TIAs) with similar symptoms.
- The sudden onset of symptoms with a prominent cardiac history and irregular pulse makes a cardioembolic stroke more likely than carotid stenosis as the immediate source.
*Head CT without contrast*
- A **head CT without contrast** is crucial for an acute stroke workup to **rule out hemorrhagic stroke** before administering thrombolytics.
- However, it does not identify the **source of an ischemic stroke**, only the acute brain changes.
*V/Q scan of his lungs*
- A **V/Q scan (Ventilation-Perfusion scan)** is used to detect **pulmonary embolism**, not the source of an ischemic stroke.
- While a **paradoxical embolism** through a patent foramen ovale (PFO) from a venous thrombus can cause stroke, a V/Q scan would not directly identify this.
*Duplex ultrasound of his right leg*
- A **duplex ultrasound of the right leg** would identify a **deep venous thrombosis (DVT)** in his edematous calf.
- While a DVT could be the source of a **paradoxical embolism** in the presence of a right-to-left shunt like a PFO, the prominent **irregular pulse** strongly points to a **cardiac source** as the primary investigation.
Question 52: A 33-year-old man presents to the emergency department with severe anxiety. He has had multiple episodes in the past treated with low dose lorazepam. The patient states that he feels as if he is going to die and that he cannot breathe. His past medical history is notable for depression and anxiety. His temperature is 98.1°F (36.7°C), blood pressure is 122/83 mmHg, pulse is 153/min, respirations are 13/min, and oxygen saturation is 98% on room air. The patient is given a low dose of lorazepam and reports a complete resolution of his symptoms. An ECG is performed and demonstrates prolongation of the P-R interval. There is a P wave preceding every QRS complex, no dropped QRS complexes, and the P-R interval does not change. His initial lab values are unremarkable. Which of the following is the best management of this patient?
A. Electrophysiological studies
B. Transcutaneous pacing
C. No further management needed (Correct Answer)
D. Sodium bicarbonate
E. Cardiac catheterization
Explanation: ***No further management needed***
- The ECG findings describe a **first-degree AV block**, which is a **benign condition** and typically does not require intervention in asymptomatic patients.
- The patient's symptoms resolved completely with lorazepam, indicating his anxiety as the primary issue, and the ECG findings are **incidental and not related** to his acute presentation.
*Electrophysiological studies*
- These studies are typically reserved for **symptomatic arrhythmias**, higher-degree AV blocks (second or third degree), or suspected **accessory pathways** not evident here.
- Given the patient's resolution of symptoms with an anxiolytic and the benign nature of first-degree AV block, **invasive studies** are not indicated.
*Transcutaneous pacing*
- **Pacing** is indicated for **symptomatic bradyarrhythmias** or **high-degree AV blocks** causing hemodynamic instability.
- The patient is **hemodynamically stable**, his heart rate is elevated due to anxiety (tachycardia), and a first-degree AV block does not typically cause severe bradycardia requiring pacing.
*Sodium bicarbonate*
- **Sodium bicarbonate** is primarily used to treat **metabolic acidosis** or certain drug toxicities (e.g., tricyclic antidepressant overdose leading to QRS widening and arrhythmias).
- There is **no indication of acidosis** or specific drug overdose in this patient, and first-degree AV block is not managed with sodium bicarbonate.
*Cardiac catheterization*
- **Cardiac catheterization** is an invasive procedure typically used to diagnose and treat **coronary artery disease** or evaluate **structural heart abnormalities**.
- There is no clinical or ECG evidence suggesting **ischemic heart disease** or significant structural issues that would warrant catheterization.
Question 53: A 51-year-old man is brought to the local emergency room in severe respiratory distress. The patient is an industrial chemist and was working in his lab with a new partner when a massive chemical spill occurred releasing fumes into their workspace. The patient and his lab partner attempted to clean up the spill before they realized it was too large for them to handle. They were not wearing protective equipment at the time, except for a pair of goggles. The fumes caused them both to begin coughing; however, this patient has a history significant for asthma. His condition worsened, which prompted lab management to call for an ambulance. On arrival at the emergency room, the patient’s respiratory rate is 42/min and oxygen saturation is 96% on room air. He is unable to speak on account of his coughing. He is clearly using accessory muscles with inspiration. A pulmonary exam reveals bilateral wheezes. He is given multiple nebulizer treatments of albuterol and is started on intravenous (IV) methylprednisolone. After 2 successive nebulizer treatments, the arterial blood gas test result shows pH 7.36, partial pressure of carbon dioxide (PCO2) 41 mm Hg, and partial pressure of oxygen (PO2) 79 mm Hg. He is now able to speak and the respiratory rate is 32/min. Which of the following is the best next step in this patient’s management?
A. Switch from nebulized albuterol to nebulized ipratropium
B. Continue to administer albuterol (Correct Answer)
C. Intubate the patient and begin mechanical ventilation
D. Administer IV prednisone in addition to IV methylprednisolone
E. Administer IV epinephrine
Explanation: ***Continue to administer albuterol***
- The patient shows **partial improvement** (decreased respiratory rate from 42 to 32/min, able to speak) but **respiratory distress persists** (RR still elevated, ongoing tachypnea).
- **Albuterol (short-acting beta-agonist)** is the **cornerstone of acute asthma management** and should be continued until bronchospasm resolves.
- The patient is responding to treatment, so the current management strategy should be maintained with continued bronchodilator therapy.
- ABG shows acceptable oxygenation (PO2 79 mm Hg) and ventilation (PCO2 41 mm Hg, pH 7.36), indicating no immediate need for escalation to intubation.
*Switch from nebulized albuterol to nebulized ipratropium*
- While **ipratropium (anticholinergic)** can be used as an **adjunct to albuterol** in severe asthma, **switching entirely from albuterol is inappropriate**.
- **Albuterol remains the primary bronchodilator** and should be continued as the patient is responding to it.
*Intubate the patient and begin mechanical ventilation*
- **Intubation is reserved** for patients with **worsening respiratory failure** despite maximal medical therapy, altered mental status, or inability to protect the airway.
- This patient demonstrates **clinical improvement** with current treatment, making intubation unnecessary at this time.
- Signs that would warrant intubation include: declining mental status, worsening hypoxemia, rising PCO2, or respiratory arrest.
*Administer IV prednisone in addition to IV methylprednisolone*
- Both medications are **corticosteroids** with similar mechanisms of action.
- Administering both simultaneously provides **no additional therapeutic benefit** and only increases the risk of corticosteroid-related adverse effects.
- The patient is already receiving appropriate systemic corticosteroid therapy with **IV methylprednisolone**.
*Administer IV epinephrine*
- **IV or IM epinephrine** is the treatment of choice for **anaphylaxis**, not routine asthma exacerbations.
- While epinephrine has bronchodilatory effects, it carries **higher cardiovascular risks** (tachycardia, arrhythmias, hypertension) compared to inhaled albuterol.
- Epinephrine in asthma is typically reserved for **life-threatening bronchospasm unresponsive to standard therapy**.
Question 54: An 80-year-old woman presents to her cardiologist for a scheduled appointment. She was shown to have moderate atrial dilation on echocardiography 3 years ago and was started on oral medications. The patient insists that she does not want aggressive treatment because she wants her remaining years to be peaceful. She has not been compliant with her medications and declines further investigations. Her heart rate today is 124/min and irregular. Which of the following organs is least likely to be affected by complications of her condition if she declines further management?
A. Kidneys
B. Spleen
C. Liver (Correct Answer)
D. Brain
E. Eyes
Explanation: ***Liver***
- While liver congestion can occur due to **right-sided heart failure**, it is less likely to be directly affected by systemic emboli originating from **atrial fibrillation** compared to organs with direct arterial supply vulnerable to clot formation.
- The liver is relatively protected from embolic damage because it receives a dual blood supply from both the **hepatic artery** and the **portal vein**, making it less susceptible to infarction from a single embolic event.
*Kidneys*
- The kidneys can be significantly affected by **systemic emboli** originating from the left atrium in **atrial fibrillation**.
- Renal emboli can cause **kidney infarction**, acute kidney injury, or chronic kidney disease due to loss of nephron function.
*Spleen*
- The spleen is highly susceptible to damage from **systemic emboli** due to its rich arterial blood supply directly from the aorta.
- Splenic infarction, characterized by **severe left upper quadrant pain**, is a common complication of emboli arising from **atrial fibrillation**.
*Brain*
- The brain is a primary target for complications of **atrial fibrillation**, with **ischemic stroke** being the most feared embolic event.
- Emboli can travel from the left atrium to the cerebral circulation, leading to severe neurological deficits.
*Eyes*
- The eyes, specifically the **retinal arteries**, are vulnerable to **cardioembolic emboli** originating from the left atrium in atrial fibrillation.
- Retinal artery occlusion can lead to sudden, painless **vision loss** or **amaurosis fugax**, making it a significant risk in patients with unmanaged atrial fibrillation.
Question 55: A 22-year-old man is brought to the emergency department 25 minutes after an episode of violent jerky movements of his arms and legs. He has no recollection of the episode. The episode lasted for 3–4 minutes. His girlfriend reports that he has not been sleeping well over the past month. He is only oriented to place and person. His temperature is 37°C (98.6°F), pulse is 99/min, respirations are 18/min, and blood pressure is 110/80 mm Hg. Neurologic examination shows no focal findings. A complete blood count as well as serum concentrations of glucose, electrolytes, and calcium are within the reference range. Urine toxicology screening is negative. An MRI of the brain shows no abnormalities. Which of the following is the most appropriate next step in management?
A. Lamotrigine
B. Lumbar puncture
C. Tilt table test
D. Electroencephalography (Correct Answer)
E. Lorazepam
Explanation: ***Electroencephalography***
- The patient experienced a **generalized tonic-clonic seizure** (violent jerky movements, postictal confusion, lack of recollection) despite normal labs and imaging.
- **Electroencephalography (EEG)** is crucial for diagnosing the type of seizure and identifying underlying epileptiform activity to guide long-term management.
*Lamotrigine*
- **Lamotrigine** is an antiepileptic drug, but initiating medication at this point without a definitive **EEG diagnosis** is premature.
- The first step after a new-onset, unprovoked seizure is to confirm the diagnosis and classify the seizure type.
*Lumbar puncture*
- A **lumbar puncture** is indicated if there's suspicion of **meningitis or encephalitis** (e.g., fever, nuchal rigidity, altered mental status not explained by postictal state), which are absent here.
- The patient's vital signs are stable, and initial lab work is unremarkable, making infection less likely.
*Tilt table test*
- A **tilt table test** is used to investigate **syncope** or orthostatic hypotension, which typically involve transient loss of consciousness without tonic-clonic movements or a prolonged postictal state.
- The patient's presentation with prominent motor activity and postictal confusion is inconsistent with syncope.
*Lorazepam*
- **Lorazepam** is a benzodiazepine used to **acutely terminate ongoing seizures** (status epilepticus) or manage acute seizure clusters.
- The patient's seizure has already resolved, and he is now in the postictal phase, so Lorazepam is not indicated at this time.
Question 56: A 67-year-old woman comes to the emergency department 1 hour after her husband saw her faint shortly after getting out of bed from a nap. She regained consciousness within 30 seconds and was fully alert and oriented. She has had 2 similar episodes in the last 5 years, once while standing in line at the grocery store and once when getting out of bed in the morning. 24-hour Holter monitoring and echocardiography were unremarkable at her last hospitalization 1 year ago. She has hypertension, depression, and asthma. Current medications include verapamil, nortriptyline, and an albuterol inhaler as needed. Her temperature is 37°C (98.4°F), pulse is 74/min and regular, respirations are 14/min, blood pressure is 114/72 mm Hg when supine and 95/60 mm Hg while standing. Cardiopulmonary examination shows no abnormalities. Neurologic examination shows no focal findings. A complete blood count and serum concentrations of electrolytes, urea nitrogen, creatinine, and glucose are within the reference range. Bedside cardiac monitoring shows rare premature ventricular contractions and T-wave inversions in lead III. Which of the following is the most likely cause of this patient's symptoms?
A. Adrenal insufficiency
B. Cardiac arrhythmia
C. Structural cardiac abnormality
D. Autonomic dysfunction (Correct Answer)
E. Hemorrhagic blood loss
Explanation: ***Autonomic dysfunction***
- This patient's symptoms are highly suggestive of **orthostatic hypotension** due to **autonomic dysfunction**, characterized by recurrent syncopal episodes upon standing from a supine or seated position.
- The drop in blood pressure from **114/72 mm Hg (supine)** to **95/60 mm Hg (standing)**, combined with the use of **verapamil** (a calcium channel blocker) and **nortriptyline** (a tricyclic antidepressant), both of which can exacerbate orthostatic hypotension, supports this diagnosis.
*Adrenal insufficiency*
- While adrenal insufficiency can cause **hypotension**, it typically presents with other systemic symptoms such as **fatigue**, **weight loss**, **hyperpigmentation**, and **electrolyte abnormalities**, none of which are noted here.
- The patient's otherwise normal lab results and the specific triggers for syncope make adrenal insufficiency less likely.
*Cardiac arrhythmia*
- Although the patient has rare **premature ventricular contractions (PVCs)** and **T-wave inversions in lead III**, these findings are typically not sufficient to explain recurrent syncope over several years, especially given an unremarkable 24-hour Holter monitoring performed a year ago.
- The syncopal episodes reliably occurring with position changes (standing) strongly point away from a primary arrhythmic cause.
*Structural cardiac abnormality*
- An **echocardiogram** performed a year ago was unremarkable, ruling out common structural causes of syncope such as **aortic stenosis**, **hypertrophic cardiomyopathy**, or **valvular disease**.
- Without new symptoms or findings to suggest a recent development, a structural abnormality is unlikely.
*Hemorrhagic blood loss*
- Acute hemorrhagic blood loss would typically present with signs of **hypovolemia**, such as **tachycardia**, **pallor**, and a significant drop in **hemoglobin**, none of which are reported in this patient.
- Her complete blood count is within the reference range, making this diagnosis highly improbable.
Question 57: A 71-year-old female is brought to the emergency room by her husband. The husband reports that they were taking a walk together one hour ago, when his wife experienced sudden, right arm and leg weakness. He noticed that she had slurred speech, and that she was not able to tell him where she was. The patient underwent an emergent CT scan, which was unremarkable, and was treated with tissue plasminogen activator (tPA). Which of the following EKG findings increases a patient's risk for this acute presentation?
A. Supraventricular tachycardia
B. Prolonged QT
C. Normal sinus rhythm
D. Atrial fibrillation (Correct Answer)
E. Atrial bigeminy
Explanation: ***Atrial fibrillation***
- **Atrial fibrillation (Afib)** is a major risk factor for **embolic stroke** due to the formation of thrombi in the left atrium, which can then dislodge and travel to the brain.
- The patient's presentation of sudden **focal neurological deficits** (**right arm and leg weakness, slurred speech, disorientation**) is highly suggestive of an acute ischemic stroke, and Afib is a common cause in this age group.
*Supraventricular tachycardia*
- While supraventricular tachycardia (SVT) can cause symptoms like palpitations, dizziness, and syncope, it is **less commonly a direct cause of cardioembolic stroke** compared to atrial fibrillation.
- The rapid heart rate in SVT typically leads to systemic symptoms rather than specific focal neurological deficits indicative of a stroke.
*Prolonged QT*
- A prolonged QT interval is primarily associated with an increased risk of developing **torsades de pointes**, a life-threatening ventricular arrhythmia.
- It does not directly increase the risk of cardioembolic stroke by causing thrombus formation in the heart chambers.
*Normal sinus rhythm*
- **Normal sinus rhythm** indicates healthy electrical activity originating from the sinoatrial node, which is the heart's natural pacemaker.
- Patients in normal sinus rhythm have a **baseline risk** of stroke, but it does not specifically increase the risk of cardioembolic stroke compared to arrhythmias like atrial fibrillation.
*Atrial bigeminy*
- Atrial bigeminy involves **premature atrial contractions (PACs)** occurring every other beat. While it can cause palpitations, it is generally considered a **benign arrhythmia**.
- Unlike atrial fibrillation, atrial bigeminy typically **does not lead to significant stasis of blood** in the atria and therefore does not significantly increase the risk of cardioembolic stroke.
Question 58: A 57-year-old man comes to the emergency department with fatigue and palpitations for several weeks. An ECG shows atrial fibrillation. Echocardiography shows thrombus formation in the left atrium. Which of the following organs is most likely to continue to function in the case of an embolic event?
A. Liver (Correct Answer)
B. Brain
C. Colon
D. Kidney
E. Spleen
Explanation: ***Liver***
- The **liver** is uniquely supplied by two major blood vessels: the **hepatic artery** and the **portal vein**.
- This **dual blood supply** provides a protective mechanism against ischemic damage from an embolic event in one of the vessels, as the other can often compensate.
*Brain*
- The **brain** is highly susceptible to embolic events, which can lead to a **stroke** due to interruption of blood flow to critical areas.
- While the Circle of Willis provides some anastomotic connections, an embolus can still cause significant **cerebral ischemia** and neuronal death.
*Colon*
- The **colon** receives its blood supply from the superior and inferior mesenteric arteries, with limited collateral circulation in some areas (e.g., the watershed areas like the splenic flexure).
- An embolic event can lead to **mesenteric ischemia** and potentially bowel infarction, a serious condition requiring immediate intervention.
*Kidney*
- The **kidneys** are end-organs with a rich but segmental arterial supply, primarily from the renal arteries.
- An embolus occluding a renal artery or one of its major branches can cause a **renal infarct**, leading to loss of kidney function in the affected segment.
*Spleen*
- The **spleen** is supplied by the splenic artery, which is an end-artery with limited collateral blood flow.
- Embolic occlusion of the splenic artery or its branches can result in a **splenic infarct**, causing pain and potential organ dysfunction.
Question 59: A 22-year-old medical student presents to a community health center due to an episode of loss of consciousness 3 days ago. She also has a history of multiple episodes of dizziness in the last year. These episodes almost always occur when she is observing surgery in the operating room. She describes her dizziness as a feeling of lightheadedness, warmth, excessive sweating, and palpitations. She feels that she will fall down if she stood longer and usually sits on the floor or leaves the room until the feeling subsides. Three days ago, she collapsed while observing an open cholecystectomy but regained consciousness after a few seconds. Once she regained consciousness, she was pale and sweating excessively. Her medical history is significant for migraines, but she is not on prophylactic therapy. Her younger brother has cerebral palsy, and her uncle had a sudden death at the age of 25. Her blood pressure is 120/80 mm Hg when lying down and 118/80 mm Hg when in a standing position. The rest of the physical examination is within normal limits. What is the next best step in the management of this patient?
A. Electroencephalogram (EEG)
B. MRI of the brain
C. Psychiatric evaluation for anxiety
D. Echocardiogram
E. Electrocardiogram (ECG) (Correct Answer)
Explanation: ***Electrocardiogram (ECG)***
- This patient presents with recurrent episodes of near-syncope and a recent syncopal episode, triggered by a stressful situation (observing surgery), along with a family history of **sudden death at a young age** (uncle at 25). These red flags suggest a possible **cardiac etiology** for her syncope, such as a **long QT syndrome** or other channelopathies, making an ECG the most crucial initial investigation.
- An ECG is a **non-invasive, inexpensive, and readily available** test that can detect structural or electrical abnormalities of the heart that could predispose to arrhythmias and syncope.
*Electroencephalogram (EEG)*
- While loss of consciousness occurred, the clinical description of lightheadedness, warmth, sweating, and palpitations followed by syncope and quick recovery with post-recovery pallor and sweating is more consistent with **vasovagal syncope** or a cardiac cause, rather than a seizure.
- The absence of typical seizure features such as **tonic-clonic movements**, post-ictal confusion, or tongue biting makes epilepsy less likely.
*MRI of the brain*
- **Brain imaging** is generally not indicated for the initial workup of syncope unless there are focal neurological deficits, head trauma, or other symptoms suggestive of a central nervous system pathology.
- The patient's symptoms are classic for syncope and do not point to a **structural brain lesion** as the cause of her loss of consciousness.
*Psychiatric evaluation for anxiety*
- While anxiety can trigger vasovagal responses, the primary concern in this case, given the **recurrent nature of syncope** and the concerning **family history of sudden death**, is to rule out a potentially life-threatening cardiac cause before attributing it solely to psychological factors.
- Attributing syncope to anxiety without a thorough cardiac workup could delay diagnosis of a serious underlying condition.
*Echocardiogram*
- An echocardiogram assesses the **heart's structure and function**, which is important in the workup of syncope. However, it is typically performed *after* an ECG, especially if the ECG reveals abnormalities suggesting a structural or electrical problem.
- While it could be a subsequent step if the ECG is abnormal, the **ECG is the most immediate and informative initial step** for ruling out electrical cardiac issues.
Question 60: A 31-year-old woman with a history of anorexia nervosa diagnosed 2 years ago presents for follow up. She says that, although she feels some improvement with cognitive-behavioral therapy (CBT), she is still struggling with her body image and fears gaining weight. She says that for the past 3 weeks she has noticed her ankles are uncomfortably swollen in the mornings. She also mentions that she still is having intermittent menstruation; her last menstrual cycle was 4 months ago. The patient denies any suicidal ideations. She has no other significant past medical history. She denies any history of smoking, alcohol consumption, or recreational drug use. The patient’s vital signs include: temperature 37.0°C (98.6°F), pulse 55/min, blood pressure 100/69 mm Hg, and respiratory rate 18/min. Her body mass index (BMI) is 17.1 kg/m2, improved from 16.9 kg/m2, 6 months ago. Her physical examination is significant for an irregular heart rhythm on cardiopulmonary auscultation. There is also significant 3+ pitting edema in the lower extremities bilaterally. An ECG reveals multiple isolated premature ventricular contractions (PVCs) with 1 10-sec episode of bigeminy. Which of the following aspects of this patient’s history and physical examination would be the strongest indication for inpatient hospitalization?
A. Lower extremity edema
B. BMI of 17.1 kg/m2
C. Pulse 55/min
D. Amenorrhea
E. Bigeminy (Correct Answer)
Explanation: **Bigeminy**
- The presence of **cardiac arrhythmias**, specifically **bigeminy** with PVCs, indicates significant cardiac instability and an increased risk of sudden cardiac death in anorexic patients. This is a medical emergency requiring urgent inpatient management.
- Anorexia nervosa can lead to **electrolyte imbalances** (e.g., hypokalemia, hypomagnesemia) and structural heart changes, predisposing to potentially lethal arrhythmias.
*Lower extremity edema*
- While concerning, **peripheral edema** in anorexia nervosa is often multifactorial (e.g., refeeding syndrome, protein deficiency, poor venous return) and typically does not independently warrant inpatient hospitalization unless it's rapidly worsening or associated with severe organ dysfunction.
- It is a symptom that needs to be addressed but is less immediately life-threatening compared to significant cardiac arrhythmias.
*BMI of 17.1 kg/m2*
- A BMI of 17.1 kg/m2 indicates that the patient is **underweight** and meets some criteria for anorexia nervosa, and while a low BMI often necessitates treatment, a BMI above 15 kg/m2 generally allows for outpatient management if other severe medical complications are absent, or if the patient is stable for outpatient care.
- Although concerning, this BMI alone is not the strongest indication for inpatient hospitalization compared to acute cardiac instability.
*Pulse 55/min*
- A pulse of 55/min is considered **bradycardia**, which is common in anorexia nervosa due to metabolic stress and adaptation to low energy states.
- While bradycardia below 50 bpm or symptomatic bradycardia may warrant intervention, a pulse of 55 bpm is not as acutely critical as complex cardiac arrhythmias like bigeminy.
*Amenorrhea*
- **Amenorrhea** (intermittent menstruation) is a common consequence of chronic malnutrition and hormonal dysregulation in anorexia nervosa.
- Although it is a significant feature of the disease and a marker of severity, it is a chronic symptom that does not typically require immediate inpatient hospitalization on its own terms, but rather long-term nutritional and hormonal rehabilitation.
