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Patient Management

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Question 281Question →

A 68-year-old man is brought to the emergency department via ambulance due to the sudden onset of severe, tearing chest pain that radiates to his back between his shoulder blades. The pain began abruptly 45 minutes ago while he was sitting at his desk. His medical history includes poorly controlled hypertension, type 2 diabetes mellitus, and stage IV chronic kidney disease. Current medications include amlodipine, lisinopril, insulin glargine, and aspirin.

Upon arrival, his temperature is 37.0°C (98.6°F), blood pressure is 185/105 mmHg in the right arm and 145/85 mmHg in the left arm. Pulse is 110/min, and respirations are 22/min. Oxygen saturation is 96% on room air. The patient appears distressed and diaphoretic. Cardiopulmonary examination reveals a regular tachycardia and a faint early diastolic murmur at the right upper sternal border. Lungs are clear to auscultation bilaterally. There is a noticeable discrepancy in radial pulse volume between the right and left arms.

Electrocardiography (ECG) shows sinus tachycardia with left ventricular hypertrophy but no acute ST-segment or T-wave changes. Initial laboratory studies reveal a serum creatinine of 2.8 mg/dL (baseline 2.5 mg/dL) and high-sensitivity troponin T within normal limits. Intravenous labetalol is initiated for blood pressure and heart rate control.

Which of the following is the most appropriate next step in the diagnostic workup?

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Answer: Transesophageal echocardiography (TEE)

Answer

Transesophageal echocardiography (TEE)
The patient's clinical presentation (sudden tearing chest pain, pulse asymmetry, a blood pressure differential, and a new early diastolic murmur indicating aortic regurgitation) is highly suspicious for an acute thoracic aortic dissection. Rapid, definitive imaging is required to confirm the diagnosis and determine the anatomical extent (Type A versus Type B). The primary imaging modalities for confirming an aortic dissection are computed tomography angiography (CTA) and transesophageal echocardiography (TEE). While CTA is typically the preferred initial modality because it is fast and non-invasive, it requires iodinated contrast, which is strictly contraindicated in this patient due to his stage IV chronic kidney disease (creatinine 2.8 mg/dL). Therefore, TEE is the most appropriate diagnostic test. It provides excellent sensitivity and specificity for detecting an intimal flap, can evaluate for complications like pericardial effusion or aortic valve involvement, can be performed quickly at the bedside, and entirely avoids nephrotoxic contrast agents.

Step-by-Step Solution

1
Analyze the patient's clinical presentation and physical examination findings.
The patient exhibits sudden, severe, tearing chest pain radiating to the back, significant pulse and blood pressure asymmetry between his arms, and a new early diastolic murmur indicating aortic regurgitation.
Identifying this classic triad of symptoms establishes a highly elevated pre-test probability for an acute thoracic aortic dissection.
2
Evaluate the initial diagnostic data (ECG and laboratory results) to rule out immediate mimics and assess patient safety for imaging.
The ECG shows no acute ischemic changes, and troponin is normal, making an acute myocardial infarction less likely. Importantly, the serum creatinine is significantly elevated at 2.8 mg/dL.
Ruling out clear ST-elevation myocardial infarction prevents inappropriate antithrombotic therapy. Noting the severely impaired renal function is critical for selecting a safe imaging modality.
3
Determine the optimal diagnostic test based on patient-specific contraindications.
Computed tomography angiography (CTA) is contraindicated due to the patient's advanced chronic kidney disease. Transesophageal echocardiography (TEE) is selected instead.
TEE provides high diagnostic accuracy for identifying an intimal flap without the need for nephrotoxic iodinated contrast material, and it can be performed quickly in hemodynamically unstable or critically ill patients.

Key Concept

In patients with a high clinical suspicion for acute thoracic aortic dissection who have severe renal impairment (preventing the use of iodinated contrast) or hemodynamic instability, transesophageal echocardiography (TEE) is the diagnostic imaging modality of choice.
Question 282Question →

A 62-year-old man with a history of decompensated alcoholic cirrhosis arrives at the emergency department accompanied by his daughter. She explains that he recently vomited a large quantity of dark red blood and clots at home. On assessment, the patient is lethargic, diaphoretic, and his extremities are cool to the touch. Vital signs reveal a blood pressure of 78/48 mm Hg, a heart rate of 132/min, a respiratory rate of 22/min, and an oxygen saturation of 95% on room air. Which of the following are the most appropriate immediate next steps in the stabilization of this patient? (Select exactly 2 options)

Select all that apply

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Answer: Placement of two large-bore peripheral intravenous catheters; Administration of a rapid bolus of intravenous isotonic crystalloids

Answer

The most appropriate immediate next steps are the placement of two large-bore peripheral intravenous catheters and the administration of a rapid bolus of intravenous isotonic crystalloids.
This patient is presenting with severe hemorrhagic shock, highly likely secondary to bleeding esophageal varices given his history of decompensated alcoholic cirrhosis. The fundamental principle of triage and management for any critically unstable patient is securing the airway, breathing, and circulation (ABCs). In the setting of severe hypovolemic shock, rapidly restoring intravascular volume is essential. This requires establishing secure, large-caliber intravenous access (such as two large-bore peripheral lines) to allow for the rapid infusion of isotonic crystalloid fluids, which will subsequently be followed by blood products. These stabilization steps must be implemented before any definitive diagnostic testing or invasive therapeutic interventions.

Step-by-Step Solution

1
Assess the patient's hemodynamic status.
The patient is hypotensive, tachycardic, diaphoretic, and lethargic, indicating profound hemorrhagic shock due to a massive upper gastrointestinal bleed.
Recognizing the severity of shock dictates the urgency and sequence of immediate lifesaving interventions.
2
Prioritize initial stabilization interventions (ABCs).
Establish adequate peripheral vascular access with two large-bore intravenous catheters and initiate rapid volume resuscitation with isotonic crystalloids.
Definitive management cannot be safely performed until the patient's intravascular volume is somewhat restored and they are hemodynamically stabilized.

Key Concept

In a patient presenting with hemorrhagic shock, initial stabilization with large-bore intravenous access and fluid resuscitation takes absolute precedence over definitive diagnostic or therapeutic procedures.
Question 283Question →

A 42-year-old woman is brought to the emergency department by her husband due to a sudden-onset, severe headache that began 3 hours ago. She describes it as the "worst headache of my life." Her medical history is unremarkable, and she takes no daily medications. Vital signs show a blood pressure of 150/90 mm Hg, heart rate of 92/min, and respiratory rate of 16/min. Neurological examination reveals no focal deficits, but she reports mild photophobia and neck stiffness. A non-contrast computed tomography (CT) scan of the head reveals no evidence of acute hemorrhage or mass effect. Which of the following is the most appropriate next step in the diagnostic workup?

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Answer: Lumbar puncture

Answer

Lumbar puncture is the correct next step because a negative head CT does not definitively rule out a subarachnoid hemorrhage in a highly suspicious presentation.
The correct answer is a lumbar puncture. In a patient presenting with a sudden-onset "thunderclap" headache highly suspicious for a subarachnoid hemorrhage (SAH), a non-contrast head CT is the best initial test. However, head CT can be falsely negative, especially if performed several hours after symptom onset, if the patient is anemic, or in cases with a very small amount of bleeding. Therefore, if the CT is negative and clinical suspicion remains high, a lumbar puncture is mandatory to evaluate for xanthochromia (bilirubin in the cerebrospinal fluid) and red blood cells to definitively confirm or rule out the diagnosis.

Step-by-Step Solution

1
Evaluate the clinical presentation.
The patient has a sudden-onset "worst headache of my life" (thunderclap headache) with neck stiffness and photophobia, which is highly concerning for a subarachnoid hemorrhage (SAH).
Identifying the classic syndrome is required to determine the pre-test probability of a life-threatening diagnosis.
2
Analyze the initial diagnostic test result.
The non-contrast head CT is negative for acute hemorrhage.
Non-contrast CT is the best initial test for SAH but can miss small bleeds or those presenting several hours to days after symptom onset.
3
Determine the next step in the diagnostic algorithm.
A lumbar puncture must be performed.
Because a negative CT scan does not definitively rule out SAH in a patient with a classic presentation, a lumbar puncture is required to look for xanthochromia (bilirubin from RBC breakdown) to establish the diagnosis.

Key Concept

In patients with a suspected subarachnoid hemorrhage and a negative non-contrast head CT, a lumbar puncture is the required next step in the diagnostic sequence.
Estimated Time:50s
Question 284Question →

A 23-year-old university student is brought to the emergency department by paramedics following an altercation outside a local restaurant. He sustained a single stab wound to the left anterior neck with a pocketknife. Upon arrival, the patient is highly agitated, diaphoretic, and exhibits audible high-pitched inspiratory sounds. Vital signs include a temperature of 37.0°C (98.6°F), blood pressure of 105/65 mm Hg, heart rate of 122/min, and respiratory rate of 28/min. Oxygen saturation is 94% on a 15 L/min non-rebreather mask. Physical examination reveals a 2-cm laceration positioned vertically between the cricoid cartilage and the angle of the mandible. There is a rapidly enlarging, pulsatile swelling beneath the wound, and the trachea is palpably deviated to the right. The patient speaks in a hoarse, whispering voice and is coughing up bright red blood. Which of the following is the single most urgent initial stabilization step for this patient?

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Answer: Establish a definitive airway via endotracheal intubation

Answer

Establish a definitive airway via endotracheal intubation
This patient presents with a Zone II penetrating neck injury accompanied by multiple 'hard signs' of severe vascular and aerodigestive tract damage, including a rapidly expanding pulsatile hematoma, stridor, hoarseness, and hemoptysis. The mass effect from the left-sided hematoma is physically displacing the trachea to the right and compressing the upper airway, resulting in stridor and impending complete airway obstruction. According to trauma resuscitation principles, securing the airway is the absolute first priority (Airway with cervical spine protection). An expanding neck hematoma can rapidly distort local anatomy, making delayed intubation extremely difficult or impossible. Therefore, establishing a definitive airway via endotracheal intubation is the single most urgent stabilization step before any imaging or transportation occurs.

Step-by-Step Solution

1
Identify the anatomical location of the injury and assess for 'hard signs' of penetrating neck trauma.
The patient has a Zone II neck injury with a rapidly expanding pulsatile hematoma, stridor, hoarseness, and hemoptysis. These are all hard signs of significant aerodigestive and vascular injury.
The presence of hard signs dictates immediate life-saving intervention rather than proceeding to advanced diagnostic imaging.
2
Evaluate the patient's airway status using the primary survey (ABCDE).
The patient exhibits stridor, a hoarse voice, and rightward tracheal deviation due to the mass effect from the left-sided expanding hematoma.
These specific clinical findings indicate impending complete upper airway obstruction, which is the most immediate threat to the patient's life.
3
Prioritize interventions based on Advanced Trauma Life Support (ATLS) principles.
Securing the airway (via endotracheal intubation, often requiring an awake fiberoptic approach or preparation for an immediate surgical airway) takes absolute precedence over imaging or waiting for surgical consultation.
Loss of the airway will result in rapid death; it must be addressed and secured before the patient leaves the resuscitation bay for definitive surgical repair.

Key Concept

In penetrating neck trauma with hard signs of vascular or aerodigestive injury (e.g., expanding hematoma, stridor) and impending airway compromise, immediate endotracheal intubation to secure the airway is the most critical initial stabilization step, preceding diagnostic imaging or definitive surgical consultation.
Question 285Question →

A 61-year-old man is evaluated in the hospital for 3 days of fever, dry cough, pleuritic chest pain, and mild hemoptysis. His medical history is significant for an orthotopic heart transplant 3 years ago for nonischemic cardiomyopathy and a history of recurrent unprovoked deep venous thrombosis. His current medications include tacrolimus, mycophenolate mofetil, prednisone, and warfarin.

Vital signs are temperature 38.6∘C38.6^\circ\text{C} (101.5∘F101.5^\circ\text{F}), pulse 102/min102/\text{min}, blood pressure 118/74 mmHg118/74\text{ mmHg}, and respirations 20/min20/\text{min}. Pulse oximetry shows 94%94\% on room air.

Laboratory results:
TestResult
Leukocyte count3,200/μL3,200/\mu\text{L}
Serum creatinine1.4 mg/dL1.4\text{ mg/dL}
INR2.42.4

A serum galactomannan assay is markedly elevated. A non-contrast CT of the chest reveals a 3 cm3\text{ cm} macronodule in the right upper lobe surrounded by a halo of ground-glass attenuation.

The infectious disease service diagnoses invasive pulmonary aspergillosis and recommends initiating intravenous voriconazole.

Which of the following simultaneous pharmacologic interventions are indicated for this patient? (Select all that apply)

Select all that apply

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Answer: Decrease the daily dose of tacrolimus; Decrease the weekly dose of warfarin

Answer

The indicated interventions are to decrease the daily dose of tacrolimus and decrease the weekly dose of warfarin.
Voriconazole is the standard of care for invasive pulmonary aspergillosis. However, it is a triazole antifungal that potently inhibits multiple cytochrome P450 enzymes, most notably CYP3A4 and CYP2C9. In a heart transplant recipient maintained on tacrolimus (a calcineurin inhibitor metabolized by CYP3A4), the introduction of voriconazole drastically increases tacrolimus serum concentrations, which can cause acute nephrotoxicity and neurologic side effects. Standard protocols dictate reducing the tacrolimus dose by 50% to 75% when starting voriconazole. Furthermore, this patient is taking warfarin for recurrent deep venous thrombosis. The more potent S-enantiomer of warfarin is metabolized by CYP2C9. Inhibition of CYP2C9 by voriconazole will rapidly elevate the patient's INR, exposing him to a high risk of life-threatening bleeding. Preemptive reduction of the warfarin dose (typically by 30% to 50%) along with frequent INR monitoring is mandatory.

Step-by-Step Solution

1
Identify the primary diagnosis and indicated treatment.
The patient has invasive pulmonary aspergillosis (fever, hemoptysis, halo sign on CT, positive galactomannan) requiring voriconazole therapy.
Establishing the correct antimicrobial is necessary before anticipating drug-drug interactions.
2
Analyze the pharmacokinetic profile of the newly initiated medication.
Voriconazole is a potent inhibitor of cytochrome P450 enzymes, particularly CYP3A4, CYP2C9, and CYP2C19.
Understanding the enzyme inhibition profile is critical for managing polypharmacy safely.
3
Reconcile the patient's current medication list against the new pharmacokinetic profile.
Tacrolimus relies on CYP3A4 for clearance. Warfarin relies heavily on CYP2C9 for clearance of its active enantiomer.
Identifying which specific maintenance drugs will be affected by enzyme inhibition prevents iatrogenic harm.
4
Determine the necessary clinical interventions.
Preemptively decrease the doses of both tacrolimus and warfarin to avoid tacrolimus toxicity (nephrotoxicity, profound immunosuppression) and warfarin toxicity (hemorrhage).
Failure to adjust these medications prior to or at the exact time of voriconazole initiation predictably leads to severe adverse events.

Key Concept

Initiation of voriconazole requires preemptive dose reductions of medications metabolized by CYP3A4 (e.g., tacrolimus) and CYP2C9 (e.g., warfarin) to prevent severe drug toxicity.
Question 286Question →

A 22-year-old college student is brought to the emergency department by his roommates because he is unarousable. He had complained of a severe headache and fever for the past 24 hours. Vital signs show temperature 39.5∘C39.5^\circ\text{C} (103.1∘F103.1^\circ\text{F}), blood pressure 80/40 mm Hg, pulse 135/min, and respirations 28/min. Oxygen saturation is 88% on room air. Physical examination reveals a petechial rash on the lower extremities and nuchal rigidity. The patient only withdraws to pain and does not open his eyes or make any sounds (Glasgow Coma Scale score of 6).

Arrange the following management steps in the most appropriate sequential order for this patient's initial stabilization and diagnostic workup.

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Answer

The correct sequence is: Perform endotracheal intubation, then Administer a rapid intravenous crystalloid bolus, then Obtain peripheral blood cultures, then Administer empiric intravenous antibiotics, and finally Obtain a non-contrast computed tomography of the head.
The correct sequence strictly follows the algorithms for acute resuscitation and suspected bacterial meningitis. Endotracheal intubation (Airway) is required first due to the patient's low GCS and hypoxia. This is immediately followed by fluid resuscitation for septic shock (Circulation). Once the patient is stabilized, blood cultures are drawn before administering empiric antibiotics to ensure maximum diagnostic yield. Finally, because the patient has altered mental status, a head CT must be performed before attempting a lumbar puncture.

Step-by-Step Solution

1
Assess and secure the airway.
Endotracheal intubation is prioritized.
The patient's Glasgow Coma Scale score of 6 and hypoxia mandate immediate airway protection before any other intervention.
2
Assess and stabilize circulation.
Rapid intravenous crystalloid bolus is administered.
The patient is in septic shock with a blood pressure of 80/40 mm Hg, requiring immediate volume resuscitation after the airway is secure.
3
Initiate diagnostic workup.
Peripheral blood cultures are obtained.
Cultures should ideally be drawn before antibiotics to identify the pathogen, provided it does not cause a significant delay in treatment.
4
Administer life-saving pharmacotherapy.
Empiric intravenous antibiotics are administered.
In suspected bacterial meningitis, early antibiotic administration reduces mortality and must not be delayed for imaging or procedures.
5
Perform further diagnostic imaging.
Non-contrast computed tomography of the head is obtained.
Due to altered mental status, a head CT is required before a lumbar puncture to rule out elevated intracranial pressure and prevent brain herniation.

Key Concept

Prioritization of ABCs (Airway, Breathing, Circulation) followed by appropriate test sequencing in septic shock and suspected bacterial meningitis.
Question 287Question →

A 56-year-old man is evaluated in the clinic for persistent hypertension. He has a 4-year history of elevated blood pressure that remains poorly controlled despite adherence to maximum tolerated doses of amlodipine, lisinopril, and hydrochlorothiazide. His blood pressure today is 162/98 mm Hg. Laboratory studies show a serum potassium level of 3.2 mEq/L and a serum sodium level of 145 mEq/L. The physician suspects primary aldosteronism.

Arrange the following diagnostic interventions in the most appropriate chronological order to establish the diagnosis, localize the pathology, and guide surgical management, assuming each successive test yields abnormal findings that necessitate further workup.

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Answer

The correct diagnostic sequence is: 1) Measurement of plasma aldosterone and renin (screening), 2) Intravenous saline infusion test (confirmation), 3) CT of the adrenal glands (initial localization), and 4) Bilateral adrenal vein sampling (definitive lateralization prior to surgery).
The correct sequence strictly adheres to current endocrine guidelines to prevent unnecessary procedures. Screening (aldosterone/renin) casts a wide net. Confirmation (saline load) ensures the disease is genuinely present. Imaging (CT) provides a structural map. Sampling (adrenal vein) provides the functional definitive proof required before removing an adrenal gland.

Step-by-Step Solution

1
Obtain an initial biochemical screening test.
Measurement of morning plasma aldosterone concentration and plasma renin activity.
Resistant hypertension accompanied by hypokalemia strongly suggests primary aldosteronism. The first step is to screen for an inappropriate ratio of aldosterone to renin (elevated ARR).
2
Perform a confirmatory biochemical test.
Intravenous saline infusion test.
Because screening tests can yield false positives, primary aldosteronism must be biochemically confirmed by demonstrating that aldosterone secretion cannot be suppressed by salt loading.
3
Localize the source using non-invasive imaging.
High-resolution CT of the adrenal glands.
Once biochemically confirmed, CT imaging is performed to visualize the adrenal glands, rule out large carcinomas, and assess anatomical feasibility for further procedures.
4
Perform definitive functional lateralization.
Bilateral adrenal vein sampling.
Adrenal incidentalomas are frequent in older adults. To prevent the surgical removal of a non-functioning adenoma in a patient who actually has bilateral hyperplasia, adrenal vein sampling is the gold standard step to confirm the functional source of excess aldosterone.

Key Concept

The diagnostic workup for primary aldosteronism proceeds sequentially through biochemical screening, biochemical confirmation, non-invasive anatomical localization, and finally invasive functional lateralization.
Question 288Question →

During a routine primary care visit, a 42-year-old man is evaluated for persistently elevated blood pressure. He was diagnosed with hypertension four years ago. Despite documented adherence to a daily regimen containing maximal doses of amlodipine, olmesartan, and chlorthalidone, his home blood pressure readings consistently remain above 150/90 mm Hg150/90 \text{ mm Hg}. He reports no headaches, palpitations, or episodic sweating. Today, his blood pressure is 162/98 mm Hg162/98 \text{ mm Hg}, and his pulse is 76/min76/\text{min}. His body mass index is 26 kg/m226 \text{ kg/m}^2. Physical examination is unremarkable. Laboratory studies from last week demonstrate a serum potassium level of 2.9 mEq/L2.9 \text{ mEq/L} and a sodium level of 144 mEq/L144 \text{ mEq/L}. A plasma aldosterone-to-renin ratio is significantly elevated, and primary aldosteronism is subsequently confirmed via a lack of aldosterone suppression following an intravenous saline infusion test. An unenhanced computed tomography (CT) scan of the abdomen reveals a 1.4-cm1.4\text{-cm}, lipid-rich, low-density nodule in the right adrenal gland. The left adrenal gland appears morphologically normal. The patient is otherwise healthy, has a good baseline functional status, and expresses a strong preference for definitive surgical management over lifelong medical therapy. Which of the following is the most appropriate next step in management?

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Answer: Adrenal vein sampling

Answer

The most appropriate next step is adrenal vein sampling.
The correct sequence for the diagnostic workup of primary aldosteronism in a surgical candidate is: 1) biochemical screening (aldosterone-to-renin ratio), 2) biochemical confirmation (e.g., oral sodium loading or saline infusion test), 3) adrenal imaging (CT scan), and 4) functional lateralization via adrenal vein sampling (AVS). AVS is standard of care for patients older than 35 because the incidence of non-functioning adrenal incidentalomas rises significantly with age. If surgery is performed based on CT findings alone, a non-functioning incidentaloma might be removed while the true source of aldosterone (such as bilateral adrenal hyperplasia) is left behind. Only patients under age 35 with marked primary aldosteronism and a clear unilateral adenoma on CT can safely bypass AVS.

Step-by-Step Solution

1
Identify the confirmed diagnosis.
The patient has biochemically confirmed primary aldosteronism, evidenced by an elevated aldosterone-to-renin ratio and a positive saline infusion suppression test.
Establishing the biochemical diagnosis is the required first step before localizing the source of hormone excess.
2
Analyze the imaging results and patient demographics.
CT shows a unilateral right adrenal nodule in a 42-year-old patient who desires definitive surgical management.
Treatment pathways diverge based on whether the patient is a surgical candidate and their age, as the prevalence of non-functioning adrenal masses increases with age.
3
Apply diagnostic test sequencing guidelines for primary aldosteronism.
Determine that adrenal vein sampling is required to confirm lateralization of aldosterone hypersecretion.
Because non-functioning adrenal incidentalomas are common in adults over age 35, imaging alone cannot reliably confirm that the visible nodule is the active source. Adrenal vein sampling prevents inappropriate adrenalectomy in cases where the true pathology is bilateral hyperplasia.

Key Concept

In patients older than 35 with confirmed primary aldosteronism and a unilateral adrenal mass on CT who desire surgery, adrenal vein sampling is required to differentiate a unilateral aldosterone-producing adenoma from bilateral adrenal hyperplasia.
Question 289Question →

A 62-year-old man is brought to the emergency department due to sudden-onset, severe substernal chest pain that radiates to his left jaw. The pain started 45 minutes ago. His blood pressure is 120/80 mmHg, and his heart rate is 90/min. An electrocardiogram shows ST-segment elevations in leads V1 through V4. His medical history includes type 2 diabetes mellitus, hyperlipidemia, and erectile dysfunction. He reports taking sildenafil 12 hours ago for erectile dysfunction. Which of the following medications is absolutely contraindicated in the initial management of this patient's acute presentation?

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Answer: Sublingual nitroglycerin

Answer

Sublingual nitroglycerin is absolutely contraindicated due to the risk of profound hypotension when combined with a recent dose of sildenafil.
The correct answer is sublingual nitroglycerin. This patient is presenting with an acute ST-segment elevation myocardial infarction (STEMI) and requires standard acute coronary syndrome (ACS) management. However, he recently took sildenafil, a phosphodiesterase-5 (PDE-5) inhibitor. PDE-5 inhibitors prevent the degradation of cyclic guanosine monophosphate (cGMP). Nitrates, such as sublingual nitroglycerin, stimulate the production of cGMP. Coadministration of nitrates and a PDE-5 inhibitor causes profound, synergistic vasodilation that can result in life-threatening hypotension and decreased coronary perfusion. Because sildenafil has a half-life of approximately 4 hours, all nitrate preparations are absolutely contraindicated for at least 24 hours after the last dose of sildenafil (and for 48 hours after tadalafil). Therefore, nitroglycerin must be completely avoided during the initial stabilization of this patient.

Step-by-Step Solution

1
Evaluate the patient's clinical presentation.
The patient has an acute anterior ST-segment elevation myocardial infarction (STEMI).
Sudden, severe chest pain with ST-segment elevations in leads V1-V4 is diagnostic of an anterior STEMI.
2
Review the patient's medication history for potential drug interactions.
The patient took sildenafil 12 hours ago.
Sildenafil is a phosphodiesterase-5 (PDE-5) inhibitor used for erectile dysfunction, which significantly affects vascular tone.
3
Determine the contraindications for standard acute coronary syndrome (ACS) pharmacotherapy.
Nitrates (e.g., sublingual nitroglycerin) are absolutely contraindicated within 24 hours of sildenafil use.
Both drugs increase intracellular cyclic guanosine monophosphate (cGMP), leading to synergistic, potentially fatal vasodilation and severe hypotension.

Key Concept

Absolute contraindication of nitrates in patients who have recently taken phosphodiesterase-5 (PDE-5) inhibitors.
Question 290Question →

Match each clinical presentation of a patient with a thyroid abnormality to the most appropriate guideline-indicated next step in their diagnostic workup.

Click a left item, then click its matching right item

Items

A 42-year-old woman with a 2.5-cm palpable thyroid nodule and a significantly suppressed serum thyroid-stimulating hormone (TSH) level
A 35-year-old man with a 1.5-cm solid, hypoechoic thyroid nodule featuring irregular margins and microcalcifications, with a normal serum TSH level
A 55-year-old woman with an incidentally discovered 0.8-cm purely spongiform thyroid nodule and a normal serum TSH level
A 65-year-old man with a massive multinodular goiter presenting with progressive stridor and dysphagia, pending surgical evaluation

Matches

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Answer

The correct matches sequence the diagnostic workup based on initial TSH status, sonographic risk stratification, and the presence of compressive anatomical symptoms.
Proper test sequencing for thyroid nodules prevents diagnostic overutilization. Suppressed TSH requires scintigraphy. Normal TSH with suspicious large nodules requires FNA. Small low-risk nodules require observation. Compressive goiters require non-contrast anatomical imaging.

Step-by-Step Solution

1
Evaluate the initial serum TSH level
Identifies if the patient is thyrotoxic (suppressed TSH) or euthyroid/hypothyroid (normal/elevated TSH)
A suppressed TSH completely alters the testing sequence, directing the clinician away from immediate biopsy and toward radionuclide scintigraphy to rule out a hyperfunctioning toxic adenoma.
2
Risk-stratify euthyroid patients using ultrasound characteristics and nodule size
Determines whether to perform a biopsy or observe
High-risk features (microcalcifications, irregular margins, hypoechoic) in nodules over 1 cm warrant biopsy, whereas low-risk features (spongiform, cystic) or small sizes (<1 cm) warrant observation, preventing unnecessary invasive procedures.
3
Assess for mechanical complications in patients with massive goiters
Identifies the need for anatomical mapping with cross-sectional imaging
Stridor indicates significant airway compromise; non-contrast CT provides spatial resolution for surgical planning without exposing the patient to intravenous iodine, which can precipitate thyrotoxicosis in multinodular goiters.

Key Concept

Thyroid nodule evaluation begins with TSH measurement to separate functioning nodules (requiring scintigraphy) from nonfunctioning ones (requiring ultrasound risk stratification to guide FNA or observation).
Estimated Time:1m 15s
Question 291Question →

A 52-year-old woman is evaluated in the hospital for sudden-onset, severe shortness of breath. She was admitted earlier today for management of osteomyelitis and recently underwent placement of a right internal jugular central venous catheter. Her blood pressure is 78/40 mmHg, pulse is 134/min, and oxygen saturation is 82% on room air. On physical examination, she is in severe respiratory distress and is diaphoretic. The trachea is deviated to the left. The neck veins are visibly distended. Breath sounds are completely absent over the right hemithorax, and the right chest is hyperresonant to percussion. Which of the following is the most appropriate next step in management of this patient?

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Answer: Needle decompression of the right chest

Answer

Needle decompression of the right chest
The correct answer is needle decompression of the right chest. This patient presents with the classic clinical triad of a tension pneumothorax: absent breath sounds on the affected side, tracheal deviation to the contralateral side, and hemodynamic instability (hypotension, tachycardia) resulting from impaired venous return. Furthermore, she has a clear risk factor: recent placement of a right internal jugular central venous catheter. Tension pneumothorax is a clinical diagnosis. The cardinal rule of initial stabilization and triage for this condition is that intervention—immediate needle decompression (typically in the 2nd intercostal space midclavicular line or 4th/5th intercostal space anterior axillary line) followed by tube thoracostomy—must never be delayed to obtain diagnostic imaging.

Step-by-Step Solution

1
Evaluate the patient's vital signs and clinical presentation.
The patient exhibits severe hypotension, tachycardia, hypoxia, and respiratory distress immediately following a high-risk procedure (central venous catheter placement).
Recognizing hemodynamic instability is the first step in acute patient triage and directs the physician toward immediate resuscitation rather than routine diagnostic workup.
2
Analyze the physical examination findings.
Absent breath sounds on the right, right-sided hyperresonance, leftward tracheal deviation, and jugular venous distention strongly indicate a right-sided tension pneumothorax.
These are the classic hallmarks of obstructive shock caused by a tension pneumothorax, which traps air in the pleural space, collapses the ipsilateral lung, and shifts the mediastinum.
3
Determine the most appropriate initial stabilization step.
Immediate needle thoracostomy (decompression) of the right chest must be performed, followed by definitive tube thoracostomy.
Tension pneumothorax is a clinical diagnosis. Waiting for imaging confirmation in an unstable patient can lead to cardiovascular collapse and death.

Key Concept

Tension pneumothorax is a clinical diagnosis requiring immediate therapeutic intervention (needle or tube thoracostomy) prior to any diagnostic imaging in hemodynamically unstable patients.
Question 292Question →

A 32-year-old man with a known history of epilepsy is brought to the emergency department by ambulance. His roommate reports that the patient has been experiencing continuous generalized tonic-clonic movements for the past 20 minutes without regaining consciousness. Upon arrival, the patient is actively seizing. The airway is secured, and peripheral intravenous access is immediately established. Arrange the following pharmacologic interventions in the correct sequential order of escalation for the management of status epilepticus, from first-line therapy to refractory management.

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Answer

The correct sequence for the pharmacologic management of status epilepticus is to administer intravenous lorazepam first, followed by intravenous fosphenytoin, and finally an intravenous propofol infusion if seizures become refractory.
Status epilepticus is a neurologic emergency requiring a step-wise pharmacologic approach. Once the airway, breathing, and circulation are stabilized, the immediate first-line therapy is a rapid-acting intravenous benzodiazepine, such as lorazepam, to quickly terminate the seizure. If the seizure persists, a second-line non-benzodiazepine antiepileptic drug (e.g., fosphenytoin, levetiracetam, or valproic acid) is administered to gain long-term control. If the patient continues to seize despite these measures, the condition is classified as refractory status epilepticus, necessitating third-line treatment with continuous infusions of general anesthetics, such as propofol, midazolam, or pentobarbital.

Step-by-Step Solution

1
Identify the clinical presentation as status epilepticus.
The patient has been actively seizing for 20 minutes without regaining consciousness, necessitating an immediate, protocolized pharmacologic escalation.
Prolonged seizures carry a high risk of permanent neurologic damage and require rapid intervention.
2
Select the first-line therapy (0-5 minutes post-IV access).
Administer intravenous lorazepam.
Benzodiazepines act rapidly on GABA receptors to terminate active seizures and are the established first-line treatment.
3
Select the second-line therapy (20-40 minutes) if seizures persist.
Administer intravenous fosphenytoin.
Non-benzodiazepine antiepileptic drugs provide sustained seizure control and treat established status epilepticus when initial benzodiazepines are insufficient.
4
Select the third-line therapy (refractory management).
Initiate an intravenous propofol infusion.
General anesthetics are required to suppress brain activity in refractory status epilepticus that does not respond to first- and second-line agents.

Key Concept

The protocolized pharmacologic escalation for status epilepticus progresses from benzodiazepines (first-line) to non-benzodiazepine antiepileptic drugs (second-line), and finally to general anesthetics (third-line) for refractory cases.
Estimated Time:1m 0s
Question 293Question →

A 52-year-old man undergoes an unenhanced computed tomography (CT) scan of the abdomen and pelvis to evaluate suspected nephrolithiasis after recently passing a calcium oxalate stone. The scan reveals an incidental 4.6-cm, well-circumscribed left adrenal mass with an unenhanced attenuation of 28 Hounsfield units. The right adrenal gland is normal. The patient is completely asymptomatic. He has no history of hypertension, palpitations, headaches, or weight changes. He takes no medications. Vital signs are temperature 37.1°C (98.8°F), blood pressure 118/76 mm Hg, heart rate 72/min, and respiratory rate 14/min. Physical examination reveals no abdominal bruits, purple striae, central adiposity, or abnormal fat distribution. Serum potassium is 4.3 mEq/L and serum creatinine is 0.9 mg/dL. Which of the following is the most appropriate next step in the diagnostic workup?

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Answer: Measurement of plasma fractionated metanephrines and a 1-mg overnight dexamethasone suppression test

Answer

The most appropriate next step is the measurement of plasma fractionated metanephrines and a 1-mg overnight dexamethasone suppression test.
The correct answer identifies the fundamental rule of adrenal incidentaloma management: all patients must undergo biochemical screening for pheochromocytoma (using plasma fractionated metanephrines) and autonomous cortisol secretion (using a 1-mg overnight dexamethasone suppression test) before any invasive procedures, advanced staging imaging, or surgical interventions. Because this patient is normotensive and normokalemic, testing for primary hyperaldosteronism (aldosterone-to-renin ratio) is not indicated.

Step-by-Step Solution

1
Identify the clinical presentation and significance of the imaging findings.
An asymptomatic, normotensive, normokalemic patient is found to have an incidental 4.6-cm, lipid-poor (28 Hounsfield units) adrenal mass.
This presentation defines an adrenal incidentaloma with high-risk imaging features (size >4 cm and attenuation >10 Hounsfield units suggest a higher risk for adrenocortical carcinoma or pheochromocytoma).
2
Determine the required universal biochemical screening for all adrenal incidentalomas.
All patients require screening for pheochromocytoma (using plasma free or 24-hour urine fractionated metanephrines) and autonomous cortisol secretion (using a 1-mg overnight dexamethasone suppression test).
Functional tumors must be identified to prevent catastrophic perioperative complications (e.g., hypertensive crisis or post-operative adrenal insufficiency) if surgery is pursued.
3
Evaluate the need for additional targeted biochemical screening.
Screening for primary hyperaldosteronism is determined to be unnecessary.
The patient is completely normotensive and normokalemic; therefore, an aldosterone-to-renin ratio is not clinically indicated.
4
Assess the correct sequence regarding invasive procedures or definitive surgery.
Surgical referral or biopsy is postponed until biochemical results are available.
Even with high-risk imaging features that will likely ultimately necessitate resection, biochemical clearance MUST precede any invasive steps to ensure patient safety.

Key Concept

All adrenal incidentalomas require initial biochemical screening for pheochromocytoma and autonomous cortisol secretion prior to invasive procedures; screening for primary hyperaldosteronism is reserved only for patients with hypertension or hypokalemia.
Question 294Question →

Emergency medical services arrive at the trauma bay with a 35-year-old construction worker who fell approximately 20 feet from scaffolding. On presentation, the patient is obtunded with gurgling respirations and profound maxillofacial bleeding. The cardiac monitor displays a sinus tachycardia of 138/min. Noninvasive blood pressure is 75/40 mm Hg, and respiratory rate is 28/min.

According to standard trauma resuscitation protocols, arrange the following initial stabilization steps in the most appropriate chronological sequence.

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Answer

The correct sequence follows the ATLS primary survey algorithm: 1) Secure the airway, 2) Assess breathing, 3) Establish circulation, 4) Evaluate disability, and 5) Expose the patient.
In the initial management of severe trauma, resuscitation must follow a strict algorithmic approach (the primary survey) to identify and treat the most immediately life-threatening injuries first. Securing the airway with simultaneous cervical spine protection is the absolute first step, as airway loss kills fastest. This is followed by assessing breathing and ventilation to ensure oxygenation. Only once the airway and breathing are established should circulation be addressed with intravenous access and fluid resuscitation. Disability is assessed next to establish baseline neurologic function, followed finally by exposing the patient completely to check for occult injuries while actively preventing hypothermia.

Step-by-Step Solution

1
Identify the most immediate threat to life.
The patient has an unprotected airway with gurgling respirations and facial bleeding.
Airway compromise leads to death more rapidly than breathing or circulatory failure, making it the first priority (Airway).
2
Determine the next requirement for cellular survival.
Once the airway is patent, adequate gas exchange must be ensured.
Without effective ventilation, a patent airway is useless. The lungs must be assessed for injuries like tension pneumothorax (Breathing).
3
Address the patient's profound hemodynamic instability.
The patient is in hypovolemic shock (blood pressure 75/40 mm Hg, heart rate 138/min).
After securing oxygenation, restoring intravascular volume and controlling hemorrhage is critical (Circulation).
4
Complete the final phases of the primary survey.
The neurologic status is assessed, followed by a full body exposure.
A baseline neurologic exam (Disability) is needed before sedation, and exposing the patient (Exposure) ensures no hidden life threats are missed.

Key Concept

The initial stabilization of a trauma patient strictly follows the primary survey algorithm: Airway (with cervical spine protection), Breathing, Circulation, Disability, and Exposure.
Question 295Question →

During a routine health maintenance examination, a physician detects an asymmetric neck swelling in a previously healthy 48-year-old female. The patient reports a 3-kg (6.6-lb) unintentional weight loss over the past two months and describes intermittent episodes of a 'racing heart.' Vital signs show a heart rate of 98/min and a blood pressure of 128/82 mmHg. Physical examination reveals a firm, mobile, 2.5-cm mass in the right anterior neck that moves with swallowing. No cervical lymphadenopathy is appreciated. Laboratory evaluation demonstrates a thyroid-stimulating hormone (TSH) level of 0.08 µU/mL (normal: 0.4–4.0 µU/mL) and a free thyroxine (T4) level of 2.1 ng/dL (normal: 0.8–1.8 ng/dL). A comprehensive neck ultrasound identifies a 2.6-cm solid, mildly hypoechoic nodule in the right thyroid lobe with increased central vascularity. Which of the following is the most appropriate next step in the diagnostic evaluation of this patient's condition?

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Answer: Radionuclide thyroid scintigraphy

Answer

Radionuclide thyroid scintigraphy is the correct next step to evaluate a thyroid nodule in the setting of a suppressed TSH.
The correct sequence for evaluating a newly discovered thyroid nodule begins with a serum TSH and a thyroid ultrasound. The TSH level dictates the subsequent pathway. If the TSH is normal or elevated, the next step is fine-needle aspiration (FNA) based on size and ultrasound characteristics. However, if the TSH is subnormal (suppressed), as seen in this patient, the next step must be radionuclide thyroid scintigraphy (using Iodine-123 or Technetium-99m). This test determines if the nodule is hyperfunctioning ('hot'), isofunctioning ('warm'), or nonfunctioning ('cold'). Hyperfunctioning nodules are virtually always benign (e.g., toxic adenoma) and do not require FNA, whereas 'cold' nodules have a higher risk of malignancy and warrant subsequent FNA.

Step-by-Step Solution

1
Analyze the patient's initial laboratory results in the context of the physical examination.
The patient has a palpable 2.5-cm thyroid nodule associated with biochemical and clinical hyperthyroidism (suppressed TSH, elevated free T4, weight loss, palpitations).
Establishing the biochemical functional status of the thyroid is the critical first branching point in the evaluation of any new thyroid nodule.
2
Evaluate the ultrasound findings alongside the laboratory results.
The ultrasound confirms a nodule larger than 1 cm with suspicious features (hypoechoic, solid, central vascularity).
Ultrasound characterizes the size and anatomy of the nodule, helping to stratify malignancy risk.
3
Apply the standard diagnostic sequencing algorithm for thyroid nodules.
Because the TSH is subnormal (suppressed), the algorithm dictates that a radionuclide thyroid scan must be performed next, regardless of how suspicious the ultrasound features appear.
A hyperfunctioning ('hot') nodule is almost never malignant and therefore does not require a fine-needle aspiration. Proceeding straight to biopsy skips this vital screening step and subjects the patient to an unnecessary invasive procedure.

Key Concept

The initial evaluation of a thyroid nodule requires measuring TSH; if TSH is suppressed, a radionuclide thyroid scan is the required next step to differentiate a benign hyperfunctioning nodule from a nonfunctioning nodule.
Question 296Question →

A 45-year-old man presents to the clinic complaining of increasing ring and shoe size over the past three years. He also reports excessive sweating, worsening snoring, and joint pain. Physical examination reveals coarse facial features, a prominent jaw, and enlarged, doughy hands. The physician strongly suspects a condition caused by a hyperfunctioning anterior pituitary adenoma. What is the correct sequence of the following diagnostic steps to evaluate this patient's condition? Arrange the items from the initial screening test to the final localization study.

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Answer

The correct diagnostic sequence for suspected acromegaly is initial screening with serum IGF-1, followed by biochemical confirmation using an oral glucose tolerance test with growth hormone measurement, and finally anatomical localization using a pituitary MRI.
The diagnostic workup for acromegaly must strictly follow a sequence of screening, confirmation, and then localization. Insulin-like growth factor 1 (IGF-1) is the best initial screening test due to its steady plasma concentration. If elevated, the diagnosis is confirmed by demonstrating a lack of growth hormone suppression during an oral glucose tolerance test. Only after biochemical confirmation should a pituitary MRI be ordered to localize the adenoma, preventing the misattribution of symptoms to a benign, nonfunctioning incidentaloma.

Step-by-Step Solution

1
Assess the clinical presentation to determine the suspected condition.
The patient has classic signs of acromegaly, prompting a workup for excess growth hormone.
Identifying the likely syndrome dictates the specific hormonal testing algorithm.
2
Select the initial screening test.
Serum IGF-1 level is chosen as the first step.
Because growth hormone is secreted in a pulsatile manner and fluctuates widely, a random growth hormone level is unhelpful. IGF-1 provides a stable, integrated assessment of growth hormone secretion.
3
Determine the confirmatory diagnostic test.
An oral glucose tolerance test (OGTT) with growth hormone measurement is chosen next.
A high IGF-1 must be confirmed by dynamic testing. In a healthy individual, a glucose load suppresses growth hormone. Failure to suppress confirms autonomous secretion.
4
Choose the appropriate imaging modality for localization.
An MRI of the pituitary gland is the final step.
Imaging is only indicated after biochemical confirmation to localize the source of excess growth hormone and plan for surgical resection.

Key Concept

Diagnostic sequencing for acromegaly always begins with biochemical testing (IGF-1 screening followed by OGTT confirmation) prior to anatomical imaging (pituitary MRI).
Question 297Question →

Paramedics transport a 19-year-old man to the trauma bay following a headfirst diving accident in a shallow lake. On arrival, he is apneic and completely unresponsive to noxious stimuli. Emergency medical personnel are actively providing assisted ventilation via a bag-valve-mask device. His temperature is 35.2∘C35.2^\circ\text{C} (95.4∘F95.4^\circ\text{F}), blood pressure is 72/40 mmHg72/40\text{ mmHg}, heart rate is 44/min44\text{/min}, and oxygen saturation is 94%94\% on 100%100\% oxygen. Physical examination reveals flaccid paralysis and absent deep tendon reflexes in all four extremities. A 6-cm6\text{-cm} scalp laceration over the vertex is actively oozing blood.

Arrange the following initial management steps in the most appropriate chronological order.

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Answer

The correct chronological sequence strictly follows the ATLS algorithm: securing the airway with in-line stabilization first, followed by fluid resuscitation for shock, then initiating vasopressors for refractory neurogenic shock, followed by a secondary survey, and ultimately transferring the stabilized patient for diagnostic imaging.
The correct sequence adheres strictly to Advanced Trauma Life Support (ATLS) principles. Securing the airway while protecting the cervical spine is the most critical intervention. Circulation is addressed next, initially with fluid resuscitation to correct potential hypovolemia, followed by vasopressors to counteract the severe vasodilation of neurogenic shock. Only after hemodynamic and respiratory stabilization is achieved can the clinician safely perform a detailed secondary survey and transport the patient out of the resuscitation bay for definitive diagnostic imaging.

Step-by-Step Solution

1
Address the patient's apnea and unresponsiveness.
Endotracheal intubation with in-line cervical stabilization is prioritized as the 'Airway' step.
Airway compromise is the most immediate threat to life and must be managed before hemodynamic or diagnostic interventions.
2
Assess and manage the severe hypotension and bradycardia.
A bolus of warmed isotonic crystalloid is administered as the first 'Circulation' step.
Hypovolemia from occult hemorrhage must be empirically treated first to optimize cardiac preload.
3
Manage refractory distributive shock.
An intravenous vasopressor like norepinephrine is initiated.
Neurogenic shock results in a profound loss of sympathetic vascular tone, requiring vasopressor support only after intravascular volume is replenished.
4
Evaluate for other traumatic injuries.
A detailed secondary survey is conducted.
The secondary survey is only safe to perform once acute life-threatening airway and circulatory issues are stabilized.
5
Obtain definitive diagnosis of the injuries.
The patient is transported for a CT of the head and cervical spine.
Imaging is a diagnostic adjunct that requires leaving the resuscitation bay; thus, it is the final step in the initial sequence.

Key Concept

In acute trauma, especially with suspected spinal cord injury and neurogenic shock, resuscitation must strictly follow the primary survey (ABCDEs). Airway management with cervical spine protection precedes circulatory support, which requires fluid resuscitation prior to vasopressor administration. Diagnostic imaging is reserved for hemodynamically stable patients.
Question 298Question →

A 64-year-old man with a history of hypertension and hyperlipidemia is brought to the emergency department by ambulance due to severe, crushing substernal chest pain that began 45 minutes ago while shoveling snow. The patient is pale, profusely diaphoretic, and appears in acute distress. Vital signs are temperature 36.6°C (97.9°F), heart rate 42/min, blood pressure 72/40 mm Hg, respiratory rate 22/min, and oxygen saturation 96% on room air. Physical examination reveals marked jugular venous distention. Auscultation of the chest demonstrates clear lung fields bilaterally with no murmurs or gallops. An immediate 12-lead electrocardiogram shows 3-mm ST-segment elevations in leads II, III, and aVF, with reciprocal ST-segment depressions in leads I and aVL. Which of the following is the most appropriate next step in the management of this patient?

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Answer: Administration of an intravenous normal saline bolus

Answer

Administration of an intravenous normal saline bolus
The correct answer is the administration of an intravenous normal saline bolus. This patient's presentation of profound hypotension, clear lung fields, and marked jugular venous distention in the setting of an acute inferior ST-elevation myocardial infarction (ST elevations in leads II, III, and aVF) strongly points to a right ventricular (RV) infarction. The ischemic right ventricle loses its contractile ability, making it extremely dependent on adequate preload (venous return) to push blood through the pulmonary circulation and into the left heart. The immediate initial stabilization step for the resulting cardiogenic shock is to maximize right-sided filling pressures by administering an intravenous fluid bolus, which improves RV cardiac output and corrects systemic hypotension.

Step-by-Step Solution

1
Interpret the electrocardiogram findings.
ST elevations in leads II, III, and aVF indicate an acute inferior wall myocardial infarction.
Identifying the location of the infarction helps predict specific complications and guides tailored management.
2
Correlate the ECG findings with the physical examination.
The combination of hypotension, clear lung fields, and jugular venous distention forms the classic triad for a right ventricular infarction.
Inferior myocardial infarctions frequently involve the right ventricle, drastically altering the hemodynamic state of the patient.
3
Determine the pathophysiologic mechanism of the patient's shock.
Right ventricular ischemia leads to decreased contractility, making the heart highly dependent on adequate preload to maintain forward blood flow.
Understanding preload dependence is crucial for selecting the correct resuscitative intervention and avoiding harmful medications.
4
Select the immediate stabilization step.
Administer an intravenous normal saline bolus.
Fluids increase right-sided filling pressures, restoring cardiac output and stabilizing the severe hypotension before moving on to definitive percutaneous coronary intervention.

Key Concept

Patients with right ventricular myocardial infarction present with hypotension, clear lungs, and jugular venous distention; they are highly preload-dependent and require immediate stabilization with intravenous fluid boluses while avoiding preload-reducing medications like nitroglycerin.
Question 299Question →

A 55-year-old man is evaluated in the emergency department for left leg pain and swelling that began 24 hours ago. He has a history of colon cancer and is currently undergoing active chemotherapy. His temperature is 37.1 C (98.8 F), blood pressure is 130/80 mm Hg, heart rate is 88/min, and respiratory rate is 14/min. Physical examination reveals a visibly swollen, tense, and erythematous left lower extremity. The left calf circumference is 5 cm larger than the right calf. There is no chest pain or shortness of breath. Which of the following is the most appropriate next step in the diagnostic workup for this patient?

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Answer: Compression ultrasonography of the lower extremity

Answer

Compression ultrasonography of the lower extremity
The correct approach for a patient with suspected deep vein thrombosis begins with risk stratification using the Wells criteria. This patient has multiple risk factors (active cancer, massive unilateral swelling, and calf asymmetry >3 cm), placing him in the high-probability category. For high-probability patients, the diagnostic algorithm dictates proceeding directly to non-invasive imaging with compression ultrasonography. D-dimer testing is skipped because a negative result would not be sufficient to rule out a thrombus in this high-risk scenario.

Step-by-Step Solution

1
Assess the pretest probability of deep vein thrombosis using the Wells criteria.
The patient scores points for active cancer, unilateral entire leg swelling, and calf swelling greater than 3 cm, indicating a high pretest probability.
Diagnostic algorithms for deep vein thrombosis depend heavily on clinical risk stratification to determine the appropriate first test.
2
Determine the appropriate initial diagnostic test based on the high risk score.
Compression ultrasonography is selected as the initial test.
In high-probability patients, the risk of disease is significant enough that a D-dimer cannot safely rule it out; direct visualization via non-invasive imaging is required.

Key Concept

In patients with a high pretest probability of deep vein thrombosis, compression ultrasonography is the most appropriate initial diagnostic test, bypassing the D-dimer assay.
Estimated Time:1m 0s
Question 300Question →

A 61-year-old man arrives at the emergency department reporting severe, crushing substernal chest pain that radiates to his jaw, accompanied by profound diaphoresis and nausea. The symptoms began abruptly 45 minutes prior. His past medical history is notable for hypertension, type 2 diabetes mellitus, and hyperlipidemia. Vital signs are temperature 36.8°C (98.2°F), heart rate 112/min, blood pressure 74/48 mm Hg, respiratory rate 22/min, and oxygen saturation 96% on room air. Physical examination reveals elevated jugular venous pressure with prominent a-waves. Pulmonary auscultation reveals clear breath sounds bilaterally without crackles or wheezes. A 12-lead electrocardiogram demonstrates 3-mm ST-segment elevations in leads II, III, and aVF, with reciprocal ST-segment depressions in leads I and aVL. Which of the following is the most urgent initial step in the management of this patient?

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Answer: Intravenous normal saline bolus

Answer

Intravenous normal saline bolus
The clinical triad of hypotension, elevated jugular venous pressure, and clear lung fields in the setting of an inferior wall myocardial infarction (ST elevations in II, III, and aVF) is highly specific for a right ventricular infarction. The ischemic right ventricle loses its contractile force and becomes exquisitely dependent on adequate preload to push blood into the pulmonary circulation and subsequently to the left heart. The immediate stabilization step is administering intravenous isotonic crystalloids to increase right-sided filling pressures and restore cardiac output.

Step-by-Step Solution

1
Analyze the clinical presentation and diagnostic findings.
The patient has hypotension, elevated jugular venous pressure, clear lung fields, and an electrocardiogram showing an inferior ST-segment elevation myocardial infarction (STEMI).
Recognizing this classic triad is necessary to diagnose right ventricular myocardial infarction.
2
Identify the underlying pathophysiology causing the hemodynamic instability.
The ischemic right ventricle loses contractility, making it exquisitely dependent on adequate preload to maintain forward blood flow to the left ventricle and systemic circulation.
Understanding the mechanism of cardiogenic shock in this specific context dictates the correct treatment pathway.
3
Determine the most urgent initial step for hemodynamic stabilization.
Administer an intravenous normal saline bolus to maximize right-sided filling pressures.
Hemodynamic stabilization (ABCs) must precede or occur concurrently with definitive diagnostic workup and subspecialty interventions.

Key Concept

Patients with right ventricular myocardial infarction (characterized by hypotension, elevated JVP, clear lungs, and inferior STEMI) are highly preload-dependent and require immediate intravenous fluid resuscitation for initial stabilization.
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