A mother presents to the family physician with her 16-year-old son. She explains, "There's something wrong with him doc. His grades are getting worse, he's cutting class, he's gaining weight, and his eyes are often bloodshot." Upon interviewing the patient apart from his mother, he seems withdrawn and angry at times when probed about his social history. The patient denies abuse and sexual history. What initial test should be sent to rule out the most likely culprit of this patient's behavior?
Q2
A 72-year-old man presents to the emergency department after a fall. The patient was found lying down on the floor in his room in his retirement community. The patient has a past medical history of Alzheimer dementia and a prosthetic valve. His current medications include donepezil and warfarin. His temperature is 97.7°F (36.5°C), blood pressure is 85/50 mmHg, pulse is 160/min, respirations are 13/min, and oxygen saturation is 97% on room air. The patient is started on IV fluids and a type and screen is performed. Laboratory values are ordered as seen below.
Hemoglobin: 13 g/dL
Hematocrit: 39%
Leukocyte count: 5,500 cells/mm^3 with normal differential
Platelet count: 225,000/mm^3
INR: 2.5
AST: 10 U/L
ALT: 12 U/L
A chest radiograph and EKG are performed and are within normal limits. A full physical exam is within normal limits. The patient's vitals are repeated. His temperature is 99.5°F (37.5°C), blood pressure is 110/70 mmHg, pulse is 90/min, respirations are 10/min, and oxygen saturation is 98% on room air. Which of the following is the best next step in management?
Q3
A 37-year-old woman presents to the Emergency Department after 8 hours of left sided flank pain that radiates to her groin and pelvic pain while urinating. Her medical history is relevant for multiple episodes of urinary tract infections, some requiring hospitalization, and intravenous antibiotics. In the hospital, her blood pressure is 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a body temperature of 36.5°C (97.7°F). On physical examination, she has left costovertebral tenderness and lower abdominal pain. Laboratory studies include a negative pregnancy test, mild azotemia, and a urinary dipstick that is positive for blood. Which of the following initial tests would be most useful in the diagnosis of this case?
Q4
A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?
Q5
A 27-year-old woman presents for her routine annual examination. She has no complaints. She has a 3-year-old child who was born via normal vaginal delivery with no complications. She had a Pap smear during her last pregnancy and the findings were normal. Her remaining past medical history is not significant, and her family history is also not significant. Recently, one of her close friends was diagnosed with breast cancer at the age of 36, and, after reading some online research, she wants to be checked for all types of cancer. Which of the following statements would be the best advice regarding the most appropriate screening tests for this patient?
Appropriate test sequencing US Medical PG Practice Questions and MCQs
Question 1: A mother presents to the family physician with her 16-year-old son. She explains, "There's something wrong with him doc. His grades are getting worse, he's cutting class, he's gaining weight, and his eyes are often bloodshot." Upon interviewing the patient apart from his mother, he seems withdrawn and angry at times when probed about his social history. The patient denies abuse and sexual history. What initial test should be sent to rule out the most likely culprit of this patient's behavior?
A. Complete blood count
B. Sexually transmitted infection (STI) testing
C. Blood culture
D. Urine toxicology screen (Correct Answer)
E. Slit lamp examination
Explanation: ***Urine toxicology screen***
- The patient's presentation with **declining grades**, **cutting class**, **weight gain**, **bloodshot eyes**, and **irritability** are classic signs of **substance abuse** in an adolescent.
- A **urine toxicology screen** is the most appropriate initial test to detect common illicit substances, especially given the clear signs pointing towards drug use.
*Slit lamp examination*
- This test is used to examine the **anterior segment of the eye**, including the conjunctiva, cornea, iris, and lens.
- While the patient has **bloodshot eyes**, this specific test would be more relevant for ruling out ocular infections or injuries, not for diagnosing the underlying cause of systemic behavioral changes.
*Complete blood count*
- A **complete blood count (CBC)** measures different components of the blood, such as red blood cells, white blood cells, and platelets.
- A CBC is a general health indicator and while it can detect infections or anemia, it is not specific or sensitive enough to identify the cause of the behavioral changes described.
*Sexually transmitted infection (STI) testing*
- Although the patient denies sexual history, all adolescents presenting with certain risk factors or symptoms may warrant STI testing in a broader health assessment.
- However, in this scenario, the primary cluster of symptoms (poor grades, cutting class, bloodshot eyes, irritability) points more directly to substance abuse than to an STI.
*Blood culture*
- A **blood culture** is used to detect the presence of bacteria or other microorganisms in the bloodstream, indicating a systemic infection (sepsis).
- The patient's symptoms are not indicative of an acute bacterial bloodstream infection, and a blood culture would not be the initial test for the presented behavioral changes.
Question 2: A 72-year-old man presents to the emergency department after a fall. The patient was found lying down on the floor in his room in his retirement community. The patient has a past medical history of Alzheimer dementia and a prosthetic valve. His current medications include donepezil and warfarin. His temperature is 97.7°F (36.5°C), blood pressure is 85/50 mmHg, pulse is 160/min, respirations are 13/min, and oxygen saturation is 97% on room air. The patient is started on IV fluids and a type and screen is performed. Laboratory values are ordered as seen below.
Hemoglobin: 13 g/dL
Hematocrit: 39%
Leukocyte count: 5,500 cells/mm^3 with normal differential
Platelet count: 225,000/mm^3
INR: 2.5
AST: 10 U/L
ALT: 12 U/L
A chest radiograph and EKG are performed and are within normal limits. A full physical exam is within normal limits. The patient's vitals are repeated. His temperature is 99.5°F (37.5°C), blood pressure is 110/70 mmHg, pulse is 90/min, respirations are 10/min, and oxygen saturation is 98% on room air. Which of the following is the best next step in management?
A. CT scan (Correct Answer)
B. Urgent blood transfusion
C. Fresh frozen plasma
D. Exploratory laparoscopy
E. Exploratory laparotomy
Explanation: ***CT scan***
- A patient with a **prosthetic valve** on **warfarin** and a fall is at high risk for **intracranial hemorrhage**, even without focal neurological deficits.
- While initial vitals improved after IV fluids, the mechanism of injury (fall) and medication profile warrant a **CT scan** of the head to rule out serious internal injury, especially given the history of dementia which might mask symptoms.
*Urgent blood transfusion*
- The patient's **hemoglobin (13 g/dL)** and **hematocrit (39%)** are within normal limits, indicating no acute need for blood transfusion due to hemorrhage.
- Transfusions are typically reserved for patients with significant blood loss or severe symptomatic anemia.
*Fresh frozen plasma*
- The patient's **INR of 2.5** is within the therapeutic range for a patient with a prosthetic valve on warfarin.
- There is no evidence of active bleeding or supratherapeutic anticoagulation that would necessitate the administration of **fresh frozen plasma (FFP)** to reverse anticoagulation.
*Exploratory laparoscopy*
- There are no clinical signs or symptoms, such as abdominal pain, distension, or evidence of intra-abdominal bleeding (e.g., declining hemoglobin, peritoneal signs), to suggest an indication for an **exploratory laparoscopy**.
- The patient's physical exam was described as normal.
*Exploratory laparotomy*
- Similar to laparoscopy, there is no clinical evidence of acute abdominal injury or hemorrhage, which would necessitate an **exploratory laparotomy**.
- This invasive procedure is reserved for cases with strong suspicion of significant intra-abdominal pathology or trauma.
Question 3: A 37-year-old woman presents to the Emergency Department after 8 hours of left sided flank pain that radiates to her groin and pelvic pain while urinating. Her medical history is relevant for multiple episodes of urinary tract infections, some requiring hospitalization, and intravenous antibiotics. In the hospital, her blood pressure is 125/83 mm Hg, pulse of 88/min, a respiratory rate of 28/min, and a body temperature of 36.5°C (97.7°F). On physical examination, she has left costovertebral tenderness and lower abdominal pain. Laboratory studies include a negative pregnancy test, mild azotemia, and a urinary dipstick that is positive for blood. Which of the following initial tests would be most useful in the diagnosis of this case?
A. Urine osmolality
B. Fractional excretion of sodium (FeNa+)
C. Renal ultrasonography (Correct Answer)
D. Contrast abdominal computed tomography
E. Blood urea nitrogen (BUN): serum creatinine (SCr) ratio
Explanation: ***Renal ultrasonography***
- This is the most appropriate initial imaging test to evaluate for **kidney stones** (given the flank pain radiating to groin and hematuria) and **hydronephrosis** (which can indicate obstruction) and assess for signs of **pyelonephritis** (given the history of recurrent UTIs and CVA tenderness).
- It is **non-invasive**, readily available, and avoids radiation exposure, making it suitable as a first-line diagnostic tool in this setting.
*Urine osmolality*
- This test primarily assesses the kidney's ability to **concentrate urine**, which is more relevant for evaluating fluid balance, diabetes insipidus, or other renal tubular disorders.
- It would not directly diagnose the cause of acute flank pain or urinary tract obstruction.
*Fractional excretion of sodium (FeNa+)*
- FeNa+ is used to differentiate between **prerenal azotemia** and **acute tubular necrosis**, indicating the kidney's response to hypoperfusion.
- While the patient has mild azotemia, FeNa+ would not identify the underlying cause of the flank pain, hematuria, or potential obstruction.
*Contrast abdominal computed tomography*
- While highly sensitive for diagnosing kidney stones and other renal pathologies, **contrast CT** exposes the patient to **ionizing radiation** and risks associated with contrast agents (e.g., contrast-induced nephropathy), especially with pre-existing azotemia.
- It is often reserved for cases where ultrasound is inconclusive or more detailed anatomical information is needed.
*Blood urea nitrogen (BUN): serum creatinine (SCr) ratio*
- This ratio is primarily used to differentiate between **prerenal** causes of acute kidney injury (high ratio, e.g., >20:1) and **intrinsic renal** causes (lower ratio, e.g., <15:1).
- While it can provide insight into the etiology of azotemia, it does not directly identify the cause of the patient's acute flank pain or potential urinary tract obstruction.
Question 4: A student health coordinator plans on leading a campus-wide HIV screening program that will be free for the entire undergraduate student body. The goal is to capture as many correct HIV diagnoses as possible with the fewest false positives. The coordinator consults with the hospital to see which tests are available to use for this program. Test A has a sensitivity of 0.92 and a specificity of 0.99. Test B has a sensitivity of 0.95 and a specificity of 0.96. Test C has a sensitivity of 0.98 and a specificity of 0.93. Which of the following testing schemes should the coordinator pursue?
A. Test A on the entire student body followed by Test B on those who are positive
B. Test A on the entire student body followed by Test C on those who are positive
C. Test C on the entire student body followed by Test B on those who are positive
D. Test C on the entire student body followed by Test A on those who are positive (Correct Answer)
E. Test B on the entire student body followed by Test A on those who are positive
Explanation: ***Test C on the entire student body followed by Test A on those who are positive***
- To "capture as many correct HIV diagnoses as possible" (maximize true positives), the initial screening test should have the **highest sensitivity**. Test C has the highest sensitivity (0.98).
- To "capture as few false positives as possible" (maximize true negatives and confirm diagnoses), the confirmatory test should have the **highest specificity**. Test A has the highest specificity (0.99).
*Test A on the entire student body followed by Test B on those who are positive*
- Starting with Test A (sensitivity 0.92) would miss more true positive cases than starting with Test C (sensitivity 0.98), failing the goal of **capturing as many cases as possible**.
- Following with Test B (specificity 0.96) would result in more false positives than following with Test A (specificity 0.99).
*Test A on the entire student body followed by Test C on those who are positive*
- This scheme would miss many true positive cases initially due to Test A's lower sensitivity compared to Test C.
- Following with Test C would introduce more false positives than necessary, as it has a lower specificity (0.93) than Test A (0.99).
*Test C on the entire student body followed by Test B on those who are positive*
- While Test C is a good initial screen for its high sensitivity, following it with Test B (specificity 0.96) is less optimal than Test A (specificity 0.99) for minimizing false positives in the confirmation step.
- This combination would therefore yield more false positives in the confirmatory stage than using Test A.
*Test B on the entire student body followed by Test A on those who are positive*
- Test B has a sensitivity of 0.95, which is lower than Test C's sensitivity of 0.98, meaning it would miss more true positive cases at the initial screening stage.
- While Test A provides excellent specificity for confirmation, the initial screening step is suboptimal for the goal of capturing as many diagnoses as possible.
Question 5: A 27-year-old woman presents for her routine annual examination. She has no complaints. She has a 3-year-old child who was born via normal vaginal delivery with no complications. She had a Pap smear during her last pregnancy and the findings were normal. Her remaining past medical history is not significant, and her family history is also not significant. Recently, one of her close friends was diagnosed with breast cancer at the age of 36, and, after reading some online research, she wants to be checked for all types of cancer. Which of the following statements would be the best advice regarding the most appropriate screening tests for this patient?
A. “Your last Pap smear 3 years ago was normal. We can repeat it after 2 more years.”
B. “Remember that information on the internet is vague and unreliable. You don't need any screening tests at this time.”
C. “Yes, you are right to be concerned. Let us do a mammogram and a blood test for CA-125.”
D. “You need HPV (human papillomavirus) co-testing only.”
E. “We should do a Pap smear now. Blood tests are not recommended for screening purposes.” (Correct Answer)
Explanation: ***We should do a Pap smear now. Blood tests are not recommended for screening purposes.***
- The current guidelines recommend Pap smears every 3 years for women aged 21-29. Although her last Pap smear was 3 years ago, it was done during pregnancy, and a **repeat Pap smear is indicated now** as she is at the end of the 3-year interval.
- **Blood tests like CA-125 are not recommended for routine cancer screening** in asymptomatic women due to their low specificity and sensitivity, which can lead to false positives and unnecessary invasive procedures.
*“Your last Pap smear 3 years ago was normal. We can repeat it after 2 more years.”*
- While a 3-year interval is generally appropriate, her last Pap smear was done 3 years ago and was performed during pregnancy, making a **repeat Pap smear indicated now** to remain within current screening guidelines.
- Delaying the Pap smear for another two years would exceed the recommended 3-year interval for cervical cancer screening in her age group.
*“Remember that information on the internet is vague and unreliable. You don't need any screening tests at this time.”*
- While caution about internet information is valid, it is **inaccurate to suggest no screening tests are needed** as the patient is due for a Pap smear based on her age and last screening date.
- Dismissing a patient's concerns outright without acknowledging valid screening needs can harm patient-doctor trust and lead to missed opportunities for preventive care.
*“Yes, you are right to be concerned. Let us do a mammogram and a blood test for CA-125.”*
- **Routine mammograms are not recommended for women under 40** without specific risk factors (e.g., strong family history, genetic mutations), which are not present here.
- **CA-125 is primarily used for monitoring ovarian cancer treatment** or evaluating women with symptoms, not for general population screening due to its low specificity.
*“You need HPV (human papillomavirus) co-testing only.”*
- **HPV co-testing (HPV test + Pap smear) is recommended for women aged 30 and older**, or as a follow-up to abnormal Pap smear results.
- For women aged 21-29, **primary Pap smear screening alone is recommended** every 3 years.
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