All practice questions

A public health task force is assessing a newly deployed rapid antigen assay for an endemic respiratory virus. Validation studies of the assay demonstrate a sensitivity of $80\%$ and a specificity of $95\%$. Epidemiological data show a significant seasonal variation in the disease burden among symptomatic patients seeking urgent care: during the peak winter months, the prevalence of the viral infection in this population is $20\%$, whereas during the summer months, the prevalence drops to $5\%$.

In early August, a symptomatic patient undergoes the rapid antigen assay at a local urgent care center, and the result is positive. Based on the seasonal prevalence, which of the following best estimates the probability that this patient actually has the viral infection?

A 68-year-old man with metastatic pancreatic cancer is admitted to the hospital with worsening confusion and respiratory distress. On evaluation, the patient is obtunded and lacks decision-making capacity. His oxygen saturation is 82% on ambient air. A legally binding advance directive in his medical record explicitly names his long-time neighbor as his healthcare proxy. The patient's adult daughter arrives at the hospital and demands that the medical team intubate him immediately to prolong his life. However, the neighbor states that the patient consistently expressed a desire to avoid mechanical ventilation under any circumstances, and the neighbor refuses consent for intubation on the patient's behalf. Which of the following is the most appropriate next step in management?

A 79-year-old woman is admitted to the surgical ward with a 3-day history of intermittent, severe abdominal cramps and frequent vomiting of green-tinged fluid. She has not had a bowel movement or passed flatus for the past 48 hours. Her past medical history includes essential hypertension, osteoarthritis, and several episodes of self-resolving right upper quadrant pain over the last decade. She has never undergone any surgical procedures. On admission, her temperature is 37.4°C (99.3°F), blood pressure is 105/65 mmHg, and heart rate is 108/min. The abdomen is significantly distended, tympanitic to percussion, and diffusely tender without guarding or rebound. Bowel sounds are hyperactive and high-pitched. Laboratory evaluation shows a leukocyte count of 11,200/mm³ and serum creatinine of 1.6 mg/dL (baseline 0.9 mg/dL). Cross-sectional abdominal imaging with contrast reveals markedly dilated loops of small bowel up to the terminal ileum, where a 3.5-cm radiopaque structure is lodged. There is also air visible within the biliary tree. After initial fluid resuscitation, which of the following is the most appropriate next step in management?

A $45$-year-old male presents to the clinic with a $2$-month history of progressive shortness of breath, chronic dry cough, subjective fevers, and a $4$-kg ($8.8$-lb) weight loss. For the past $15$ years, he has worked in a stone fabrication facility specializing in quartz and granite countertops. His vital signs are temperature $37.8^\circ\text{C}$ ($100.0^\circ\text{F}$), heart rate $92$/min, respiratory rate $18$/min, and blood pressure $128/82$ mmHg. Pulse oximetry is $96\%$ on room air. Physical examination reveals diminished breath sounds in the upper lung fields. Chest radiography demonstrates diffuse, small, rounded opacities predominantly in the upper lobes, as well as enlarged bilateral hilar lymph nodes exhibiting a rim of calcification. Which of the following are the most appropriate next steps in the comprehensive management of this patient? (Select all that apply)

A public health task force is evaluating the performance of various diagnostic and screening tests across different clinical settings. They must anticipate how altering diagnostic thresholds or changing the tested population will impact the statistical characteristics of the tests. Match each clinical scenario with the most accurate description of its impact on the test's performance metrics.

A $71$-year-old male is admitted directly to the resuscitation bay following an episode of profuse hematemesis at his residence. For the preceding $2$ weeks, he noted intermittent melena, subjective fevers, and a deep, gnawing lumbar ache. His surgical history is significant for a synthetic graft repair of an infrarenal abdominal aortic aneurysm $4$ years ago. On arrival, he is confused and diaphoretic. Vital signs include a temperature of $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), heart rate of $134/\text{min}$, blood pressure of $72/40\text{ mmHg}$, and respiratory rate of $22/\text{min}$. Abdominal examination reveals a well-healed midline scar and mild epigastric tenderness without guarding. Intravenous access is established, and aggressive fluid resuscitation is initiated, but his blood pressure remains $76/44\text{ mmHg}$. Which of the following is the most appropriate next step in management?

A city health department is evaluating a new rapid antigen test for a circulating strain of influenza. Surveillance data indicates that the prevalence of this influenza strain among symptomatic patients presenting to urgent care clinics is $20\%$. In this specific clinical setting, validation studies demonstrate that the rapid antigen test has a positive predictive value of $50\%$ and a sensitivity of $80\%$.

Based on these findings, what is the specificity of this new rapid antigen test? (Enter the value as a percentage)

A prospective cohort study is conducted to evaluate the association between a diet high in ultra-processed foods and the subsequent development of metabolic syndrome. Researchers follow 5,000 healthy adults over a 10-year period. At the conclusion of the study, they compare the incidence of metabolic syndrome between participants in the highest quartile of ultra-processed food consumption and those in the lowest quartile. The analysis yields a relative risk (RR) of $1.45$ with a 95% confidence interval of $[0.92, 2.15]$. Which of the following is the most accurate statistical interpretation of these findings?

A 31-year-old female, G2P1, at 10 weeks gestation presents for her first prenatal visit. She works as an emergency department nurse. She reports a history of an anaphylactic reaction to baker's yeast that resulted in intubation during her teenage years. Her childhood vaccination records were lost in a house fire, and she is unsure of her complete immunization history, although she notes receiving an annual influenza vaccine. Laboratory testing reveals she is non-immune to both rubella and hepatitis B. Which of the following immunization actions are appropriate for this patient during the course of her current pregnancy? (Select all that apply)

A 28-year-old pregnant woman, G2P1, at 32 weeks gestation presents to the emergency department complaining of severe muscle aches, abdominal cramps, nausea, and diarrhea for the past 24 hours. She has a history of opioid use disorder and admits to using intranasal heroin daily, but reports she ran out yesterday. She also states she has been feeling profoundly sad, having low energy, and sleeping excessively over the past 3 weeks. Her medical records indicate two previous psychiatric hospitalizations for manic episodes characterized by grandiosity and a decreased need for sleep. Vital signs are temperature 37.2°C (99.0°F), blood pressure 140/90 mm Hg, heart rate 110/min, and respiratory rate 18/min. Physical examination reveals dilated pupils, frequent yawning, rhinorrhea, and piloerection. Fetal heart rate monitoring reveals a baseline of 150/min, moderate variability, positive accelerations, and no decelerations.

The physician counsels the patient on the risks of untreated opioid withdrawal during pregnancy, including preterm labor and fetal demise. The patient demonstrates a clear understanding of these risks but states, "I need to leave right now to take care of my 3-year-old at home. I refuse to be admitted, but I want to get better. I will come to the outpatient clinic tomorrow morning."

Which of the following is the most appropriate next step in management?

A local public health department is investigating an outbreak of acute gastrointestinal illness in a suburban community. Over the past 14 days, 49 individuals have presented to local clinics with severe abdominal cramps and bloody diarrhea; most patients are afebrile. Stool cultures from the initial patients grow gram-negative bacilli that form colorless colonies on MacConkey agar with sorbitol. The epidemiological team constructs an epidemic curve plotting the onset of symptoms for all 49 cases. The curve reveals an initial sharp peak of 28 cases occurring within a tightly clustered 48-hour window. Four days after this initial peak, a second distinct peak of 15 cases is observed. Five days later, a third, smaller peak of 6 cases occurs. Local clinics are overwhelmed, and community leaders demand immediate action. Based on the clinical presentation and the temporal pattern of the outbreak, which of the following is the most appropriate next step in management?

A 58-year-old woman comes to the clinic for a routine health maintenance examination. She states that she feels generally well but mentions experiencing a few episodes of light vaginal spotting over the past three weeks. She has not had a menstrual period since age 51. Her medical history is notable for severe plaque psoriasis, for which she takes oral cyclosporine. She has a 20-pack-year history of smoking but quit 18 years ago. Her last colonoscopy was 8 years ago, with normal findings. Her last cervical cancer screening was 3 years ago and was negative. She has not received any immunizations in the past 5 years. Which of the following is the most appropriate next step in the management of this patient?

A research group evaluates a novel high-resolution ultrasound technique for diagnosing giant cell arteritis (GCA) in patients over 50 years of age presenting with new-onset headaches. A prospective study enrolls 1,000 such patients. Each patient undergoes the novel ultrasound followed by a temporal artery biopsy, which serves as the gold standard.

Biopsy results confirm the diagnosis of GCA in 150 patients. The novel ultrasound finding is present in 120 of these biopsy-confirmed cases. Among the patients with a negative biopsy, the ultrasound finding is present in 34 patients.

Based on these study results, what is the positive likelihood ratio ($LR+$) of this novel ultrasound finding for diagnosing giant cell arteritis?

A 32-year-old man comes to the urology clinic after noticing a firm swelling in his left testicle approximately two weeks ago. He reports no pain, dysuria, urinary frequency, or recent trauma. He has no history of sexually transmitted infections. Vital signs are within normal limits. On physical examination, the overlying scrotal skin appears normal. Palpation of the left testicle reveals a $3\text{-cm}$, rock-hard, non-tender nodule located at the lower pole. The lesion does not transilluminate and cannot be separated from the testis. The right testicle and bilateral epididymides are soft and normal to palpation. A scrotal ultrasound confirms the presence of a solid, hypervascular, hypoechoic intratesticular mass. Serum laboratory testing demonstrates an alpha-fetoprotein (AFP) level of $145\text{ ng/mL}$ (normal $< 10\text{ ng/mL}$) and a $\beta$-hCG level of $92\text{ mIU/mL}$ (normal $< 2\text{ mIU/mL}$). Which of the following is the most appropriate next step in management?

A $71$-year-old man is transported to the resuscitation bay after collapsing at his home. His daughter, who witnessed the event, reports that he suddenly complained of an agonizing, tearing pain in the center of his chest that radiated to his upper back right before losing consciousness. His past medical history is significant for poorly controlled hypertension, chronic obstructive pulmonary disease, and a prior exploratory laparotomy for a small bowel obstruction.

On physical examination, the patient is lethargic, diaphoretic, and pale. Vital signs are:
Temperature: $36.9^\circ\text{C}$ ($98.4^\circ\text{F}$)
Heart rate: $128\text{ /min}$
Blood pressure: $76/42\text{ mm Hg}$
Respiratory rate: $26\text{ /min}$
Oxygen saturation: $92\%$ on room air.

Cardiovascular examination reveals distended neck veins, faint heart sounds, and a newly appreciated high-pitched, blowing early diastolic murmur best heard at the right upper sternal border. Lung auscultation is clear bilaterally. The abdomen is soft and non-distended.

A bedside point-of-care ultrasound demonstrates a large pericardial effusion with right ventricular diastolic collapse, as well as a visible intimal flap in the proximal ascending aorta.

Based on the clinical and sonographic findings, what is the best initial intervention for this patient?

A 74-year-old man with a history of Parkinson disease and severe chronic constipation is brought to the emergency department by his family due to a 2-day history of progressive abdominal distention, crampy lower abdominal pain, and obstipation. Vital signs are temperature 37.2°C (99.0°F), blood pressure 135/85 mm Hg, pulse 92/min, and respirations 16/min. Physical examination reveals a markedly distended, tympanitic abdomen. The abdomen is non-tender, with no guarding, rigidity, or rebound tenderness. Laboratory studies show a leukocyte count of 11,000/mm³ and a normal serum lactate level. Arrange the following steps in the most appropriate chronological sequence for the standard definitive management of this patient's condition.

Pair the following clinical situations with the most appropriate legal or ethical term related to end-of-life care.

Physicians frequently encounter conflicts between a patient's right to privacy and the duty to protect third parties or comply with legal mandates. For each of the following patient encounters, which of the following is the most appropriate response? Match each clinical scenario with its corresponding correct legal or ethical action.

A 34-year-old construction worker arrives at the trauma center following a workplace accident. He was struck on the right arm by a swinging metal pipe. He reports severe pain in his right arm. His vital signs are within normal limits. Examination of the right upper extremity reveals marked swelling and an obvious angular deformity in the middle of the upper arm. The overlying skin is intact. When asked to move his hand, the patient demonstrates a "wrist drop" and cannot actively straighten his fingers at the metacarpophalangeal joints. He reports numbness over the back of his right hand near the thumb. Radial and ulnar pulses are strong and symmetrical. An X-ray confirms a closed, displaced transverse fracture of the midshaft of the humerus. Which of the following is the most appropriate initial management for this patient?

A pharmacovigilance team utilizes a nationwide electronic health record (EHR) database to evaluate the risk of acute kidney injury (AKI) associated with a novel broad-spectrum antibiotic. The researchers identify all adult patients in the database who were prescribed the novel antibiotic between January 2020 and December 2024. They also identify a comparison group of adults who were prescribed a standard alternative antibiotic during the same timeframe. The researchers then analyze the longitudinal EHR data through December 2025 to determine the incidence of AKI in both groups. Which of the following statements regarding this study design are correct?