Block 1 June 2022
1. B- The formula for a 95% confidence interval for data that follow a normal distribution is x̅ +/-
(1.96 x Standard Error), where x̅ is the mean. The lower end of the confidence interval is thus
130 – (1.96 x 5), which equals 120.2, and the higher end of the confidence interval is 130 +
(1.96 x 5) which equals 139.8. This best matches the range of 120-140.
2. E- Six weeks ago, this patient developed acute renal failure and ischemia-induced acute
tubular necrosis (ATN) in the setting of cardiac arrest due to underlying coronary artery
disease. This was most likely due to severe renal ischemia due to impaired cardiac output.
The diagnosis of ATN is supported by his oliguria, azotemia, and urinary granular casts. Two
weeks after his initial cardiac arrest, the oliguria and azotemia resolved, representing the
recovery of acute tubular necrosis. Most patients with ATN will experience tubular re-
epithelialization and spontaneous full recovery. This is not uncommon after several weeks.
Severe acute kidney injury can be lethal if not properly managed, although the question states
that this patient’s death was secondary to a cardiac arrhythmia, likely due to damage
sustained from ischemia during cardiac arrest.
3. D- For a normal distribution of data, mean (average) is the most reliable measure of central
tendency. In this example, the mean leukocyte count is 7500 cells/mm3. Based on this, 50% of
individuals will have leukocyte counts greater than 7500 and 50% will have leukocyte counts
less than 7500.
4. A- This patient has vaginal pain, pruritus, and dyspareunia. Physical exam reveals edematous,
erythematous vaginal mucosa with white discharge, suggestive of a candidal infection. A
vaginal smear reveals the presence of normal vaginal epithelium and pseudohyphae,
confirming the diagnosis of vaginal candidiasis. This patient is at risk for the development of
this condition based on her history of type 2 diabetes mellitus.
5. E- Emphysema is a component of chronic obstructive pulmonary disease characterized by
loss/damage of alveolar elastin and lung parenchyma due to a protease/antiprotease
imbalance. This causes increased alveolar collapse on expiration, air trapping and
hyperinflation, impaired ventilation, and increased dead space, leading to hypoxemia and
hypercapnia. Patients may experience shortness of breath and dyspnea on exertion/at rest.
Over time patients may develop severe hyperinflation and a barrel chest. Breathing through
, pursed lips is performed in order to prevent expiratory alveolar collapse (auto-PEEP).
Pulmonary function testing classically reveals decreased FEV1:FVC ratio (<70%), increased
residual volume (obstruction), and impaired diffusion (decreased DLCO). For additional
information check out MedSchool Bootcamp’s video on COPD.
6. A- Bipolar I disorder is characterized by at least one episode of mania. This is defined as
seven or more days of abnormal and persistently elevated, irritable, or expansive mood along
with increased goal-directed activity, behavior, or energy that are not attributed to another
medical condition, psychotic disorder, or substance abuse. This patient has evidence of
psychotic features, including delusions (married to the president's brother, receiving specific
instructions from higher being) that further support this diagnosis. For additional information
check out MedSchool Bootcamp's video on Bipolar Disorders.
7. B- Peak A represents the initial antibody production by B cells that are exposed to this live
attenuated bacteria’s antigens for the first time (clonal selection). Between Peaks A and B,
some of these cells become memory B cells, awaiting future infections/exposures. Peak B is
characterized by amplification of the antibody production response due to previous exposure
(clonal expansion). This “second exposure” achieves a more robust response than the “first
exposure” in a shorter amount of time. Following this second peak, a lack of continued
stimulation leads to cellular apoptosis in the majority of the antibody producing cells. A small
population remains as memory cells. For additional information check out MedSchool
Bootcamp's video on Antibody Properties.
8. B- This patient has evidence of exocrine pancreatic insufficiency, including fatty stools (large
volume, floating) and significant weight loss. In the setting of insufficient pancreatic enzyme
secretion and activation (e.g., lipase), fat-soluble vitamins (A,D,E,K) are likely to become
deficient. This patient has symptoms of vitamin A deficiency (e.g., xerosis cutis). For additional
information check out MedSchool Bootcamp's video on Pancreatic Insufficiency.
9. G- Serum prostate-specific antigen (PSA) is a high value test, where a high value indicates a
positive result. At the original threshold, values > 4.1 ng/mL were considered a positive result.
If the threshold is lowered to 2.0 ng/mL, some patients who were previously considered
negative will be considered positive. This population of newly positive patients with PSA levels
between 2.0 and 4.1 ng/mL will have a higher proportion of false positive results compared to
the population of patients with a PSA > 4.1 ng/mL. Overall this will lead to more false positives,
which decreases the reliability of a positive test result. Thus, the PPV will decrease.
Meanwhile, the NPV will increase, because the patients with a PSA between 2.0 and 4.1 had a
, higher chance of being a false negative with the original threshold, so changing the threshold
such that these patients become positive decreases the amount of false negatives and
increases the reliability of a negative result. For additional information check out MedSchool
Bootcamp's video on Diagnostic Test Thresholds.
10. D– Absorbing and understanding complex information is extremely difficult shortly after
receiving unexpected and emotional news. By providing only a small amount of the most
need-to-know information, the physician gives the family time to process and understand that
information before giving additional details that may otherwise be forgotten.
11. H- Physiologic changes of exercise include increases in venous return (preload), contractility,
and heart rate. Point X on the diagram represents the steady state condition regarding right
atrial pressure and cardiac output in this patient prior to exercise. The slope of the cardiac
function curve (solid line) is increased by increases in contractility and heart rate as
demonstrated with exercise (left-upward shift of the curve). Point G represents baseline
venous return (as we have not left the initial vascular/venous return curve). Point F represents
pathologic decreases in venous return, while point H correctly corresponds to physiologic
increases in venous return in the setting of exercise. For additional information check out
MedSchool Bootcamp's video on Physiologic Changes of Exercise.
12. B- This patient is experiencing lower urinary tract symptoms, including impaired bladder
emptying, urinary hesitancy, and postvoid dribbling, indicating lower urinary tract obstruction.
Physical exam revealed a diffusely enlarged, firm, and nontender prostate—consistent with
benign prostatic hyperplasia (BPH). BPH is a very common condition of advancing age. It is
due to prostate stimulation by dihydrotestosterone (DHT) which is converted from testosterone
by 5 alpha-reductase. This stimulation leads to hyperplasia of the periurethral lobes (lateral
and middle) of the prostate and subsequent symptomatology.
13. E- This patient with sickle cell disease (SCD) is presenting with symptoms of biliary colic (e.g.,
postprandial RUQ pain, nausea, lack of fever) in the presence of gallstones confirmed by
ultrasound. This is most likely secondary to underlying hemolysis linked to the patient’s sickle
cell disease. Typical lab findings in hemolysis include a decreased haptoglobin, increased
LDH, and increased unconjugated bilirubin. The elevation in unconjugated bilirubin results
from heme catabolization and can increase the risk of pigmented calcium bilirubinate gallstone
formation. For additional information check out MedSchool Bootcamp's video on Hemolysis.
14. D- This patient has evidence of autosomal dominant familial hypercholesterolemia, supported
by tendinous xanthomas (hands and Achilles), familial history of early onset atherosclerosis
, (coronary artery disease) affecting males and females, and hypercholesterolemia on serum
lipid studies. Patients with Apo C-II or lipoprotein lipase deficiency commonly develop familial
hyperchylomicronemia with hypertriglyceridemia and its possible sequelae (pancreatitis,
eruptive xanthomas) with no increased risk of atherosclerosis.
15. A- Controlled cellular destruction (shrinkage, cytoplasmic budding, noninflammatory, plasma
membranes intact) is indicative of apoptosis. Apoptosis is a highly programmed self-contained
process of cell destruction. This can occur via two general pathways: extrinsic and intrinsic.
The intrinsic pathway is initiated by a stimulus (p53, loss of regulating factor) that leads to a
change in the intracellular balance of pro-apoptotic (Bad, Bak, Bad) and anti-apoptotic (Bcl-2,
Bcl-xL) proteins. These pro-apoptotic proteins enhance mitochondrial membrane permeability,
leading to cytochrome c release (increases in cytochrome c) into the cytosol, and eventual
activation of caspase 9 that then activates additional caspases. For additional information
check out MedSchool Bootcamp's video on Apoptotic Pathways.
16. D- Increasing the sample size from 500 to 1500 will increase the power of the study, which is
the ability of a study to correctly reject the null hypothesis when the null hypothesis is false. If
the chances of the study correctly rejecting the null hypothesis increase, the chances of the
study failing to reject the null hypothesis when the null hypothesis is false will decrease. This
means the chances of making a type II error will decrease. Mathematically, the power = 1 -
probability of making a type II error, so if the power increases, the probability of making a type
II error must decrease.
17. A- Reactive gliosis is the process involved in repairing CNS tissue after injury. This is mediated
by the proliferation of astrocytes within the CNS. These cells facilitate nervous tissue repair
and scar formation. Astrocytes are the most abundant form of glial cell, functioning as
structural support for neurons, supporting and forming the blood brain barrier, removing and
metabolizing neurotransmitters (glymphatic system), extracellular potassium buffering, and
acting as a glycogen reserve. For additional information check out MedSchool Bootcamp's
video on Histologic Timeline of Stroke.
18. C- Cardiac function during a myocardial infarction is severely compromised. This patient’s
ECG reveals ST-segment elevations and new Q waves in leads V4-V6, representing occlusion
of the distal LAD/LCX. This infarcted tissue comprises a large portion of the left ventricle.
During the acute setting, ventricular contractility will decrease in an effort to balance oxygen
supply and demand. This is seen as a large drop in cardiac output. This decreased output
leads to increased retention of blood within the left ventricle, as an increased end-diastolic
1. B- The formula for a 95% confidence interval for data that follow a normal distribution is x̅ +/-
(1.96 x Standard Error), where x̅ is the mean. The lower end of the confidence interval is thus
130 – (1.96 x 5), which equals 120.2, and the higher end of the confidence interval is 130 +
(1.96 x 5) which equals 139.8. This best matches the range of 120-140.
2. E- Six weeks ago, this patient developed acute renal failure and ischemia-induced acute
tubular necrosis (ATN) in the setting of cardiac arrest due to underlying coronary artery
disease. This was most likely due to severe renal ischemia due to impaired cardiac output.
The diagnosis of ATN is supported by his oliguria, azotemia, and urinary granular casts. Two
weeks after his initial cardiac arrest, the oliguria and azotemia resolved, representing the
recovery of acute tubular necrosis. Most patients with ATN will experience tubular re-
epithelialization and spontaneous full recovery. This is not uncommon after several weeks.
Severe acute kidney injury can be lethal if not properly managed, although the question states
that this patient’s death was secondary to a cardiac arrhythmia, likely due to damage
sustained from ischemia during cardiac arrest.
3. D- For a normal distribution of data, mean (average) is the most reliable measure of central
tendency. In this example, the mean leukocyte count is 7500 cells/mm3. Based on this, 50% of
individuals will have leukocyte counts greater than 7500 and 50% will have leukocyte counts
less than 7500.
4. A- This patient has vaginal pain, pruritus, and dyspareunia. Physical exam reveals edematous,
erythematous vaginal mucosa with white discharge, suggestive of a candidal infection. A
vaginal smear reveals the presence of normal vaginal epithelium and pseudohyphae,
confirming the diagnosis of vaginal candidiasis. This patient is at risk for the development of
this condition based on her history of type 2 diabetes mellitus.
5. E- Emphysema is a component of chronic obstructive pulmonary disease characterized by
loss/damage of alveolar elastin and lung parenchyma due to a protease/antiprotease
imbalance. This causes increased alveolar collapse on expiration, air trapping and
hyperinflation, impaired ventilation, and increased dead space, leading to hypoxemia and
hypercapnia. Patients may experience shortness of breath and dyspnea on exertion/at rest.
Over time patients may develop severe hyperinflation and a barrel chest. Breathing through
, pursed lips is performed in order to prevent expiratory alveolar collapse (auto-PEEP).
Pulmonary function testing classically reveals decreased FEV1:FVC ratio (<70%), increased
residual volume (obstruction), and impaired diffusion (decreased DLCO). For additional
information check out MedSchool Bootcamp’s video on COPD.
6. A- Bipolar I disorder is characterized by at least one episode of mania. This is defined as
seven or more days of abnormal and persistently elevated, irritable, or expansive mood along
with increased goal-directed activity, behavior, or energy that are not attributed to another
medical condition, psychotic disorder, or substance abuse. This patient has evidence of
psychotic features, including delusions (married to the president's brother, receiving specific
instructions from higher being) that further support this diagnosis. For additional information
check out MedSchool Bootcamp's video on Bipolar Disorders.
7. B- Peak A represents the initial antibody production by B cells that are exposed to this live
attenuated bacteria’s antigens for the first time (clonal selection). Between Peaks A and B,
some of these cells become memory B cells, awaiting future infections/exposures. Peak B is
characterized by amplification of the antibody production response due to previous exposure
(clonal expansion). This “second exposure” achieves a more robust response than the “first
exposure” in a shorter amount of time. Following this second peak, a lack of continued
stimulation leads to cellular apoptosis in the majority of the antibody producing cells. A small
population remains as memory cells. For additional information check out MedSchool
Bootcamp's video on Antibody Properties.
8. B- This patient has evidence of exocrine pancreatic insufficiency, including fatty stools (large
volume, floating) and significant weight loss. In the setting of insufficient pancreatic enzyme
secretion and activation (e.g., lipase), fat-soluble vitamins (A,D,E,K) are likely to become
deficient. This patient has symptoms of vitamin A deficiency (e.g., xerosis cutis). For additional
information check out MedSchool Bootcamp's video on Pancreatic Insufficiency.
9. G- Serum prostate-specific antigen (PSA) is a high value test, where a high value indicates a
positive result. At the original threshold, values > 4.1 ng/mL were considered a positive result.
If the threshold is lowered to 2.0 ng/mL, some patients who were previously considered
negative will be considered positive. This population of newly positive patients with PSA levels
between 2.0 and 4.1 ng/mL will have a higher proportion of false positive results compared to
the population of patients with a PSA > 4.1 ng/mL. Overall this will lead to more false positives,
which decreases the reliability of a positive test result. Thus, the PPV will decrease.
Meanwhile, the NPV will increase, because the patients with a PSA between 2.0 and 4.1 had a
, higher chance of being a false negative with the original threshold, so changing the threshold
such that these patients become positive decreases the amount of false negatives and
increases the reliability of a negative result. For additional information check out MedSchool
Bootcamp's video on Diagnostic Test Thresholds.
10. D– Absorbing and understanding complex information is extremely difficult shortly after
receiving unexpected and emotional news. By providing only a small amount of the most
need-to-know information, the physician gives the family time to process and understand that
information before giving additional details that may otherwise be forgotten.
11. H- Physiologic changes of exercise include increases in venous return (preload), contractility,
and heart rate. Point X on the diagram represents the steady state condition regarding right
atrial pressure and cardiac output in this patient prior to exercise. The slope of the cardiac
function curve (solid line) is increased by increases in contractility and heart rate as
demonstrated with exercise (left-upward shift of the curve). Point G represents baseline
venous return (as we have not left the initial vascular/venous return curve). Point F represents
pathologic decreases in venous return, while point H correctly corresponds to physiologic
increases in venous return in the setting of exercise. For additional information check out
MedSchool Bootcamp's video on Physiologic Changes of Exercise.
12. B- This patient is experiencing lower urinary tract symptoms, including impaired bladder
emptying, urinary hesitancy, and postvoid dribbling, indicating lower urinary tract obstruction.
Physical exam revealed a diffusely enlarged, firm, and nontender prostate—consistent with
benign prostatic hyperplasia (BPH). BPH is a very common condition of advancing age. It is
due to prostate stimulation by dihydrotestosterone (DHT) which is converted from testosterone
by 5 alpha-reductase. This stimulation leads to hyperplasia of the periurethral lobes (lateral
and middle) of the prostate and subsequent symptomatology.
13. E- This patient with sickle cell disease (SCD) is presenting with symptoms of biliary colic (e.g.,
postprandial RUQ pain, nausea, lack of fever) in the presence of gallstones confirmed by
ultrasound. This is most likely secondary to underlying hemolysis linked to the patient’s sickle
cell disease. Typical lab findings in hemolysis include a decreased haptoglobin, increased
LDH, and increased unconjugated bilirubin. The elevation in unconjugated bilirubin results
from heme catabolization and can increase the risk of pigmented calcium bilirubinate gallstone
formation. For additional information check out MedSchool Bootcamp's video on Hemolysis.
14. D- This patient has evidence of autosomal dominant familial hypercholesterolemia, supported
by tendinous xanthomas (hands and Achilles), familial history of early onset atherosclerosis
, (coronary artery disease) affecting males and females, and hypercholesterolemia on serum
lipid studies. Patients with Apo C-II or lipoprotein lipase deficiency commonly develop familial
hyperchylomicronemia with hypertriglyceridemia and its possible sequelae (pancreatitis,
eruptive xanthomas) with no increased risk of atherosclerosis.
15. A- Controlled cellular destruction (shrinkage, cytoplasmic budding, noninflammatory, plasma
membranes intact) is indicative of apoptosis. Apoptosis is a highly programmed self-contained
process of cell destruction. This can occur via two general pathways: extrinsic and intrinsic.
The intrinsic pathway is initiated by a stimulus (p53, loss of regulating factor) that leads to a
change in the intracellular balance of pro-apoptotic (Bad, Bak, Bad) and anti-apoptotic (Bcl-2,
Bcl-xL) proteins. These pro-apoptotic proteins enhance mitochondrial membrane permeability,
leading to cytochrome c release (increases in cytochrome c) into the cytosol, and eventual
activation of caspase 9 that then activates additional caspases. For additional information
check out MedSchool Bootcamp's video on Apoptotic Pathways.
16. D- Increasing the sample size from 500 to 1500 will increase the power of the study, which is
the ability of a study to correctly reject the null hypothesis when the null hypothesis is false. If
the chances of the study correctly rejecting the null hypothesis increase, the chances of the
study failing to reject the null hypothesis when the null hypothesis is false will decrease. This
means the chances of making a type II error will decrease. Mathematically, the power = 1 -
probability of making a type II error, so if the power increases, the probability of making a type
II error must decrease.
17. A- Reactive gliosis is the process involved in repairing CNS tissue after injury. This is mediated
by the proliferation of astrocytes within the CNS. These cells facilitate nervous tissue repair
and scar formation. Astrocytes are the most abundant form of glial cell, functioning as
structural support for neurons, supporting and forming the blood brain barrier, removing and
metabolizing neurotransmitters (glymphatic system), extracellular potassium buffering, and
acting as a glycogen reserve. For additional information check out MedSchool Bootcamp's
video on Histologic Timeline of Stroke.
18. C- Cardiac function during a myocardial infarction is severely compromised. This patient’s
ECG reveals ST-segment elevations and new Q waves in leads V4-V6, representing occlusion
of the distal LAD/LCX. This infarcted tissue comprises a large portion of the left ventricle.
During the acute setting, ventricular contractility will decrease in an effort to balance oxygen
supply and demand. This is seen as a large drop in cardiac output. This decreased output
leads to increased retention of blood within the left ventricle, as an increased end-diastolic
