All practice questions

A $58$-year-old man with a history of decompensated alcoholic cirrhosis is recovering from surgical repair of a fractured right femur. During the initial postoperative period, his severe pain was well-controlled with scheduled intravenous morphine. His current laboratory results show a serum albumin of $2.6$ g/dL, total bilirubin of $4.2$ mg/dL, and an International Normalized Ratio (INR) of $1.9$. The medical team is preparing to transition him to an oral morphine regimen for discharge to a skilled nursing facility. Morphine is a classic high hepatic extraction ratio medication ($E_H > 0.7$). Compared to a healthy adult with normal hepatic function, which of the following pharmacokinetic changes is most likely to be observed in this patient upon receiving the oral formulation?

An ambulatory care physician conducts a same-day evaluation for a 32-year-old woman reporting a three-day history of worsening nausea, unsteady gait, and a coarse tremor in both hands. Her past medical history is significant for bipolar disorder, which has been excellently controlled on a stable dose of lithium carbonate for the past four years. She denies any recent changes to her prescribed psychiatric medications. The patient mentions she sustained a moderately painful ankle sprain while hiking four days ago. Which of the following details, if elicited during the medical history, would best explain her current clinical presentation?

A 4-month-old male infant is brought to the emergency department for poor feeding, a weak cry, and decreased spontaneous movements over the past 2 days. The parents mention that the infant has not had a bowel movement in 4 days and that they recently started giving him a pacifier dipped in raw honey to soothe him. Vital signs show a temperature of 36.8°C (98.2°F), heart rate of 120/min, respiratory rate of 30/min, and blood pressure of 85/50 mmHg. On physical examination, the infant exhibits profound generalized hypotonia, an absent gag reflex, and sluggish pupillary responses. The physician suspects a neuromuscular junction disorder caused by a bacterial neurotoxin.

Arrange the following cellular events in the pathogenesis of this patient's illness in chronological order, from the initial cellular interaction to the ultimate physiologic consequence.

A 19-year-old woman is evaluated in the hematology clinic prior to a scheduled wisdom tooth extraction. She has a history of heavy menstrual bleeding and frequent epistaxis since childhood. Her older brother and mother have similar bleeding tendencies. Laboratory studies show:

Hemoglobin: $11.2 \text{ g/dL}$
Platelet count: $165,000/\text{mm}^3$
Prothrombin time (PT): 11 seconds (Normal: 11-15 s)
Activated partial thromboplastin time (aPTT): 39 seconds (Normal: 25-35 s)
Ristocetin cofactor activity: decreased

A test dose of intravenous desmopressin (DDAVP) is administered to determine if it can be used for hemostatic prophylaxis during her dental procedure. Thirty minutes after the infusion, her platelet count is rechecked and has fallen to $38,000/\text{mm}^3$. Which of the following best describes the underlying molecular pathophysiology of this patient's bleeding disorder?

A 48-year-old woman is brought to the emergency department due to a 3-day history of worsening confusion, generalized fatigue, and fever. Her medical history is unremarkable, and she takes no medications. Her temperature is $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), blood pressure is $142/85\text{ mm Hg}$, and heart rate is $108/\text{min}$. Physical examination is notable for scleral icterus and scattered petechiae over her lower extremities. Neurological examination reveals mild disorientation but no focal motor or sensory deficits.

Laboratory results are as follows:

A presumptive diagnosis of thrombotic thrombocytopenic purpura (TTP) is made.

Arrange the following diagnostic and management steps in the most appropriate chronological sequence for this patient.

A 62-year-old woman comes to the urgent care clinic complaining of profuse, watery, foul-smelling diarrhea for the past 4 days. She reports having up to 8 bowel movements a day, accompanied by lower abdominal cramping and a low-grade fever. Ten days ago, she was discharged from the hospital after a 5-day admission for community-acquired pneumonia, for which she completed a course of levofloxacin. Her temperature is 38.1°C (100.6°F), pulse is 105/min, and blood pressure is 110/70 mm Hg. Physical examination reveals a mildly distended abdomen with diffuse tenderness but no rebound or guarding. Laboratory studies show a leukocyte count of 18,000/mm³. Stool enzyme immunoassay is positive for a bacterial exotoxin. Which of the following best describes the primary intracellular mechanism of the exotoxin responsible for this patient's gastrointestinal findings?

A 34-year-old man with a history of intravenous drug use presents to the emergency department with a 2-week history of high fever, chills, and progressive fatigue. He reports no recent travel or sick contacts. His temperature is 39.2°C (102.6°F), blood pressure is 110/70 mmHg, and heart rate is 112/min. Auscultation reveals a new, harsh holosystolic murmur at the left lower sternal border. Which of the following physical examination findings are highly characteristic of the most likely diagnosis? (Select all that apply)

A 31-year-old woman is evaluated in the outpatient rheumatology clinic for a 3-month history of symmetric joint pain and swelling in her wrists and metacarpophalangeal joints. She also reports profound fatigue and the recent appearance of a mildly pruritic, erythematous rash over her nose and cheeks that worsens after sun exposure. Vital signs are within normal limits. Physical examination confirms the presence of a malar rash and active synovitis in the hands. Which of the following is the most appropriate initial step in laboratory evaluation?

A 58-year-old man is evaluated in the intensive care unit for high fever, severe hypotension, and progressive respiratory distress. Four days ago, he received an infusion of CD19-directed chimeric antigen receptor (CAR) T cells for refractory diffuse large B-cell lymphoma. His temperature is 39.8°C (103.6°F), blood pressure is 82/50 mm Hg despite receiving 3 L of intravenous crystalloid over the past two hours, pulse is 128/min, and respirations are 28/min. Oxygen saturation is 88% on room air, which improves to 94% on a high-flow nasal cannula. Physical examination reveals warm extremities and bounding pulses. Laboratory studies demonstrate marked elevations in serum ferritin, C-reactive protein, and lactate. Blood cultures are drawn, and empiric broad-spectrum intravenous antibiotics are initiated. Despite these measures and the initiation of a norepinephrine infusion, the patient remains hemodynamically unstable. Which of the following best describes the primary molecular target of the most appropriate specific pharmacotherapy to reverse this patient's acute deterioration?

Distinct stressors and physiologic cues induce specific morphologic changes in human tissues. For each of the following patient presentations, match the clinical scenario with the most accurate description of the underlying cellular adaptation or injury mechanism.

Emergency medical services arrive at the emergency department with a 34-year-old woman experiencing sudden-onset respiratory distress and profound dizziness. The patient's symptoms started abruptly 20 minutes prior, shortly after consuming a meal at a local seafood restaurant. She is extremely anxious, struggling to breathe, and reporting a sensation of her throat closing. She has no known significant past medical history. Vital signs upon arrival are temperature 37.1°C (98.8°F), blood pressure 82/48 mm Hg, pulse 132/min, and respiratory rate 28/min. Oxygen saturation is 90% on room air. Physical examination demonstrates prominent facial angioedema, widespread erythematous urticarial plaques across her trunk, and diffuse expiratory wheezes on lung auscultation. She is speaking in short, fragmented sentences.

Which of the following interventions represent the most appropriate simultaneous initial steps in stabilizing this patient? (Select all that apply)

Evaluate the following clinical scenarios of patients with suspected pulmonary embolism. What is the most appropriate next step in the diagnostic workup for each patient? Match each clinical presentation to its guideline-indicated diagnostic test.

An otherwise healthy 48-year-old individual arrives at an urgent care facility reporting three days of worsening shortness of breath, a productive cough, and subjective fevers. Vital signs show a temperature of 38.7°C (101.7°F), a heart rate of 102/min, a respiratory rate of 24/min, and an oxygen saturation of 93% on ambient air. During the physical examination, the physician focuses on the right lower posterior thorax. Percussion over this area produces a dull note. Palpation reveals increased tactile fremitus. Auscultation demonstrates bronchial breath sounds and distinct egophony. Based on these specific physical examination findings, which of the following best describes the underlying pathologic state in this patient's right lower lung?

Evaluate the following distinct patient encounters. For each clinical presentation, select the most appropriate targeted laboratory investigation required to establish or confirm the primary suspected diagnosis.

A 62-year-old man is evaluated in the hospital on postoperative day 7 following a coronary artery bypass grafting. He has been recovering well and is scheduled for discharge to a cardiac rehabilitation facility in two days. His daily medications include aspirin, atorvastatin, metoprolol, and subcutaneous unfractionated heparin for venous thromboembolism prophylaxis. Today, his vital signs are temperature 37.0°C (98.6°F), blood pressure 128/78 mmHg, pulse 76/min, and respirations 14/min. Physical examination reveals a clean, healing sternal incision, clear lung fields, and normal heart sounds. There is no lower extremity edema, erythema, or tenderness. Routine morning laboratory results show:

Hemoglobin: 11.2 g/dL
Leukocyte count: 8,500/mm³
Platelet count: 85,000/mm³ (baseline on admission was 210,000/mm³)
Creatinine: 1.1 mg/dL

Which of the following is the most appropriate next step in laboratory evaluation?

A 34-year-old man who actively injects black tar heroin is brought to the emergency department by his friends due to progressive difficulty opening his mouth, sweating, and severe muscle spasms in his back. He has not received any preventative medical care or vaccinations in over two decades. Physical examination reveals diaphoresis, a fixed facial smile, and pronounced arching of the back. A necrotic, purulent ulcer is noted on his left forearm. The causative pathogen produces a potent neurotoxin responsible for his clinical presentation. Arrange the following steps in the pathophysiological cascade of this toxin's mechanism of action in the correct chronological sequence, from initial host interaction to the ultimate physiologic effect.

A 64-year-old man with a history of heart failure, type 2 diabetes mellitus, and chronic kidney disease stage 5 on hemodialysis is brought to the emergency department by his family due to worsening confusion and unsteadiness over the past two days. His medications include lisinopril, amlodipine, and phenytoin, which he takes for a history of remote post-traumatic seizures. Two weeks ago, a routine chemistry panel showed a blood urea nitrogen of $68 \text{ mg/dL}$, serum creatinine of $5.4 \text{ mg/dL}$, and serum albumin of $2.2 \text{ g/dL}$. At that same visit, his total serum phenytoin level was $6.5 \text{ \mu g/mL}$ (therapeutic range: $10-20 \text{ \mu g/mL}$). Believing the level was subtherapeutic, the physician increased his daily phenytoin dose. Physical examination today reveals bilateral horizontal nystagmus, wide-based gait ataxia, and dysarthria. A repeat total serum phenytoin level today is $13.5 \text{ \mu g/mL}$. Which of the following pharmacokinetic principles best explains why the patient is experiencing neurotoxicity despite a total drug level within the normal therapeutic range?

A 58-year-old man is admitted to the cardiac care unit for the management of recurrent, sustained ventricular tachycardia. An intravenous infusion of lidocaine is initiated at a constant maintenance rate. Forty-eight hours later, the patient develops cardiogenic shock due to an acute myocardial infarction, resulting in severely reduced cardiac output and diminished tissue perfusion. Pharmacokinetic analysis in this low-flow state indicates that both the systemic clearance ($CL$) and the apparent volume of distribution ($V_d$) of lidocaine have decreased by approximately 50%. Assuming the intravenous infusion rate remains constant, which of the following best describes the expected changes in the drug's elimination half-life and steady-state plasma concentration compared to his baseline?

Paramedics rush a 62-year-old man to the resuscitation bay following the abrupt onset of a tearing, excruciating pain between his shoulder blades. He has a known medical history of Marfan syndrome. Upon arrival, his clinical status rapidly deteriorates, marked by escalating confusion and severe dyspnea. Vital signs reveal a blood pressure crash to 75/40 mm Hg, accompanied by a compensatory heart rate of 130/min. Auscultation of the precordium identifies a newly developed early diastolic decrescendo murmur situated at the right upper sternal border. The attending physician immediately suspects that a massive accumulation of fluid in the pericardial space has acutely complicated the primary cardiovascular event.

Which of the following physical examination findings would confirm the presence of this specific pericardial complication? (Select 3)

Match each clinical scenario with the most accurate description of its expected primary pharmacokinetic alteration.