Incorrect 24

Question 1

A 40-year-old woman with a 25-year history of type 1 diabetes mellitus has a serum creatinine concentration of 2.5 mg/dl. A creatinine clearance test is ordered to determine the
glomerular filtration rate. This test is limited, compared to an inulin clearance test, because of which of the following properties of creatinine?
CJ A) Actively pumped into the distal convoluted tubule
B) Crosses freely into the loop of Henle
C) Reabsorbed into the collecting duct
U D) Secreted by the proximal tubule

Answer 1

D. Page 570 (636) of FA2019.

GFR = Clearance of inulin.
Normal GFR = 100 mL/min

Creatinine clearance overestimates GFR because creatinine is excreted by tubules.

Remember the definitions. The afferent arteriole brings many nutrients and substances to the glomerulus, where filtration happens based on pressures.
Then along the tubule, some things are reabsorbed (all sugar, proteins, etc in PCT), while some things are secreted (PAH).

Everything that was filtered and secreted gets excreted (clearance). Inulin is neither reabsorbed nor secreted so it is freely filtered and best indicates GFR.
Creatinine is secreted by the kidney, so it overestimates GFR.

Question 2

A 10-year-old boy who was adopted from the Democratic Republic of Congo 2 weeks ago is brought to the physician for an initial examination. He appears slim, has thin extremities,
and is in no distress. His temperature is 37 .3°C (99.1°F), pulse is 100/min, respirations are 20/min, and blood pressure is 118/68 mm Hg. The lungs are clear, and heart sounds are
normal. The abdomen is soft and nontender, and there is no hepatosplenomegaly. There are four 0.5-mm, firm, nontender nodules: two over the right iliac crest, one on the left thigh,
and one on the left knee. Examination of a skin snip from one of the nodules shows microfilariae. Which of the following is the most likely vector of this patient’s infection?
A) Black fly
B) Bodylouse
u C) Cu/ex species mosquito
U D) lxodes species tick
E) Reduviid bug

Answer 2

A. Page 159 (164) FA2019
Onchocerca volvulus by the female black fly.
The other answer chocies are generally related to bacteria or unrelated to any nematodes.
This child is presenting with practically no symptoms besides the four black skin nodules indicative of O

Question 3

At 2:00 AM, after sleeping for 5 hours, a 32-year-old man with type 2 diabetes mellitus has a decrease in serum glucose concentration to 37 mg/dl. In response to the hypoglycemia,
cortisol secreted by the adrenal cortex induces the synthesis of which of the following enzymes in the adrenal medulla?
CJ A) Acetyl-CoA carboxylase
B) Homocysteine methyltransferase
C) Methionine adenosyltransferase
U D) Methylmalonyl-CoA racemase
E) Phenylethanolamine N-methyltransferase

Answer 3

E. Page 83 FA2019.

This question is a simple biochemistry question regarding mechanisms of managing hypoglycemia.
Cortisol is one of the defenses against hypoglycemia.
The question asks for an enzyme in the adrenal medulla, which synthesizes NE and Epi.
Choice E is the only relevant enzyme. It works with SAM to convert NE to Epi and is upregulated by cortisol.

You should know exactly what the other enzymes are for.
Acetyl-CoA carboxylase is the first enzyme for fatty acid synthesis and takes Acetyl CoA and yields Malonyl CoA.
Choice B is related to homocysteine becoming methionine and is related to homocystinuria.
Choice C is a relevant enzyme because it makes the SAM that PMNT uses it is not upregulated by cortisol.
Choice D, a “racemase” is probably an enzyme youve never heard of. It is an epimerase involved in fatty acid and amino acid breakdown.

Question 4

A 63-year-old woman undergoes operative repair of a leaking berry aneurysm in the circle of Willis. Two days later, a CT scan of the head shows a widening of the subarachnoid
space. Which of the following changes in cerebrospinal fluid is the most likely cause of this finding?
CJ A) Decreased absorption by the choroid plexus
B) Decreased movement through the arachnoid villi
C) Decreased movement through the cerebral aqueduct
U D) Increased absorption by the choroid plexus
E) Increased movement through the arachnoid villi
F) Increased production by the choroid plexus

Answer 4

B. Page 510 (570) and page 491 (571).

This patient has a communicating hydrocephalus, as is evident by the fact that there is no obstruction that is impeding the CSF flow.
The patient has a widening of the subarachnoid space because the arachnoid granulations are not absorbing the CSF, most likely due to inflammatory injury.
Blood is inflammatory. Her leaking aneurysm has caused inflammation and damaged the arachnoid granulations.
The arachnoid granulations absorb CSF and send it to the dural venous sinuses, which empty into the internal jugular vein.

The other choices also do not make much sense.

The choroid plexus does not absorb CSF, it produces CSF.
Choice C is indicative of a noncommunicating (obstructive) hydrocephalus.

Question 5

A 30-year-old woman comes to the physician because of a 2-week history of right flank pain. Her blood pressure is 168/98 mm Hg. Physical examination shows a 7-cm mass that is
palpated in the right side of the abdomen. A CT scan shows a mass in the retroperitoneal space on the right side that is compressing the renal artery. If the perfusion pressure to the
affected kidney is decreased, but glomerular filtration rate and renal plasma flow remain unchanged, which of the following mechanisms mediates the autoregulation in the renal
arterioles in this patient?
A) Decreased afferent and efferent arteriolar resistance
B) Decreased afferent arteriolar resistance
u C) Decreased efferent arteriolar resistance
U D) Increased afferent and efferent arteriolar resistance
E) Increased afferent arteriolar resistance

Answer 5

B. Page 571 (638) and page 295 (317) FA2019
Glomerular dynamics and autoregulation are high-yield.
For the kidney there are myogenic and tubuloglomerular feedback mechanisms of autoregulation.
The myogenic mechanism is where the afferent arteriole controls blood flow purely based off of blood pressure entering the kidney.
The tubuloglomerular feedback mechanism involves the JGA and a paracrine signaling mechanism utilizing ATP, adenosine, and NO.

For our patient, there is decreased blood entering the renal artery.
They also mention that the autoregulatory mechanism will preserve GFR and RPF.
If you constrict either arteriole, you will alter the GFR and the RPF, so delete choices D and E.

Afferent arteriole dilation (usually caused by prostaglandins, PDA) usually increases GFR and RPF but since perfusion into the kidney
is reduced, nothing will be severely altered.

Question 6

A male newborn is delivered in the hospital at 40 weeks’ gestation to a 31-year-old primigravid woman following an uncomplicated spontaneous vaginal delivery. The mother
immigrated to the USA from Brazil at 20 weeks’ gestation. At 8 weeks’ gestation, she was evaluated because of a 1-month history of low-grade fever, marked fatigue, and diffuse
lymphadenopathy. Her symptoms resolved spontaneously, and she received no treatment. At that time, test results for Epstein-Barr virus and cytomegalovirus were negative. The
mother’s only medication was a prenatal vitamin. The newborn is 33 cm (13 in; 25th percentile) long and weighs 2438 g (5 lb 6 oz; 35th percentile); head circumference is 31 cm (12
in; 3rd percentile). Temperature is 37.0°C (98.6°F), pulse is 120/min, respirations are 18/min, and blood pressure is 80/50 mm Hg. Eye examination shows chorioretinitis. CT scan of
the head shows hydrocephalus and cranial calcifications. This newborn’s congenital infection was most likely acquired by the mother via which of the following modes of
transmission?
U A) Contact with fomites
B) Ingestion of undercooked meat
C) Inhalation of air droplets
u D) Kissing
E) Tick bite

Answer 6

B. Page 156 (161).
Toxoplasma gondii.
The mother is fine. The baby has the triad of chorioretinitis, hydrocephalus (head circumference is in 3rd percentile), and intracranial calcifications.
In the USA, ingestion of undercooked pork is the most likely answer choice.

Oocysts in cat feces are dangerous so pregnant women should avoid cat litter.
But even if contact with cat litter is an answer choice, cysts in meat is the most common route of infection and more likely.

Question 7

A 4 7-year-old man comes to the physician because of abdominal enlargement and rectal bleeding for 3 days. He drinks approximately twelve 12-ounce cans of beer daily. Physical
examination shows scleral icterus and bleeding internal hemorrhoids. Increased pressure in which of the following veins is the most likely cause of the hemorrhoids in this patient?
CJ A) Inferior rectal vein
B) Inferior vena cava
C) Internal pudenda! vein
U D) Middle rectal vein
E) Superior rectal vein

Answer 7

E. Page 360 (401) FA2019.
This patient has internal hemorrhoids, which are above the pectinate line. That area has the superior rectal vein (suprior above).
Below the pectinate line are external painful hemorrhoids, which have the inferior and middle rectal veins (inferior below). Easy

Question 8

A clinical study is designed to evaluate the association of caffeine consumption and pancreatic cancer. In this study, alpha is set at 0.05 and beta at 0.10. Which of the following best
describes the likelihood of missing an association between caffeine consumption and pancreatic cancer in this study?
CJ A) 5%
B) 10%
C) 85%
U D) 90%
E) 95%

Answer 8

B. Page 262 (274) FA2019.
The “likelihood of missing an association” is a false-negative. Stating there is no effect or difference when there reall yis one is beta.
Type 2 error is the beta value itself, 0.10 which is 10%. Very straightforward question.

Do not confuse this with power, which is 1-beta, and that would be 90% here.

Question 9

A 22-year-old woman comes to the physician because of nausea and vomiting for 1 week. She has a 6-month history of headaches. She works as a data entry technician and has
recently found it difficult to focus on the text. She also has had trouble looking up from her desk at the clock on the wall without moving her head. Neurologic examination shows
marked vertical gaze palsy and impaired accommodation. Horizontal gaze is normal. An MRI of the brain is most likely to show a tumor at which of the following locations?
A) Arcuate nucleus
B) Frontal cortex
C) Pineal gland
D) Pituitary gland
E) Pontine paramedian reticular formation

Answer 9

C. Page 516 (576) FA2019.
This patient is presenting with Parinaud syndrome, which has a vertical gaze palsy due to compression of the tectum.
She most likely has a pinealoma. This is a very straightforward and simple question.

In males, this can lead to precocious puberty and they would have elevated hCG because this is similar to germ cell tumors like a seminoma

Question 10

In a study of antibiotic resistance, a strain of Escherichia coli resistant to ampicillin but sensitive to streptomycin is cultured with a strain of Salmonella enteritidis sensitive to
ampicillin but resistant to streptomycin. After 4 hours of cocultivation, the broth is plated onto solid medium containing both ampicillin and streptomycin. S. enteritidis bacteria that are
resistant to both antibiotics grow at a frequency of one per 100 cells. Which of the following is the most likely mechanism of the acquisition of ampicillin resistance by the
S. enteritidis?
A) Conjugation
B) Gene duplication
UC) Point mutation
U D) Transduction
E) Transposition

Answer 10

A. Page 130 FA2019.
Conjugation is when two bacteria mate through a conjugal bridge and transfer a plasmid from one to the other.
Here the E coli is resistant to ampicillin and the Salmonella is resistant to streptomycin. They are cultured together.
Now the Salmonella is resistant to both antibiotics. This is because the E coli gave its ampicillin resistance plasmid to the Salmonella.

Gene duplication and point mutation are irrelevant.

Transduction involves a virus.

Transposition is an event that occurs within the same one bacteria, not between 2 different bacteria.

Question 11

A 15-month-old boy is brought to the physician by his mother because of a 9-month history of recurrent bacterial infections. The patient has not had recurrent viral infections. He is at
the 10th percentile for length and weight. Physical examination shows multiple areas of honey yellow, crusted lesions over the lower extremities. A Gram stain of one of the lesions
shows many gram-positive cocci in clusters but no leukocytes. Laboratory studies show no abnormalities except for a leukocyte count of 30,000/mm3. This patient most likely has a
rare autosomal recessive disease leading to a lack of CD18 expression. The leukocytes would be deficient in which of the following characteristics?
A) Cytokine production
B) Helper T-cell function
u C) lmmunoglobulin gene rearrangement
U D) Killing of intracellular bacteria
E) Migration

Answer 11

E. Page 117 FA2019.
This patient has LAD1, a deficiency in LFA1 integrin CD18. Autosomal recessive.
Patients present with recurrent skin and mucosal bacterial infections due to phagocyte dysfunction.
There is impaired migration and chemotaxis. Delayed separation of the umbilical cord is usually a notable problem.

Question 12

A 38-year-old woman, gravida 4, para 4, comes to the physician because of a 6-month history of urinary incontinence when sneezing and coughing. Physical examination shows
normal-appearing female external genitalia. When the patient is asked to perform a Valsalva maneuver, leakage of urine from the urethra is detected. She is given instructions to
perform Kegel exercises to strengthen the muscles of the perineum. Which of the following muscles in this patient is most likely to remain unaffected by the exercises?
A) Bulbospongiosus
B) Deep transverse perinea! muscle
C) External urethral sphincter
D) Internal anal sphincter
E) lschiocavernosus

Answer 12

D. Page 588 (660) FA2019.
This patient has stress incontinence, as is evident from her urine leakage after extensive intra-abdominal pressure from a cough or sneeze.
The problem is due to urethral hypermobility or the intrinsic urethral sphincter.
Kegel exercises strengthen the pelvic floor. The main targets for treatment are the levator ani muscles; iliococcygeus, pucococcygeus, & puborectalis.
Pessaries are another treatment option.

Regardless, any exercise will generally strengthen skeletal muscle. The internal anal sphincter is smooth muscle under autonomic control.
It will not strengthen from exercise.
The external anal sphincter, on the other hand, is under pudendal nerve control (feces leakage during delivery) and would strengthen from exercise.

Question 13

A 1-week-old newborn is brought to the physician because of poor feeding, vomiting, and progressive lethargy during the past 4 days. She was born at term; pregnancy, labor, and
delivery were uncomplicated, and she had no congenital anomalies. She is being breast-fed. She has a healthy 2-year-old brother; a sister died at the age of 10 days after a full-term
birth. Physical examination shows decreased muscle tone and poor responsiveness; reflexes are normal. Her serum bicarbonate concentration is 8 mEq/L, pH is 7.15, and plasma
ammonia concentration is 10 times the upper limit of normal. Which of the following is the most likely cause?
A) Mitochondrial disorder
B) Mucopolysaccharidosis disorder
u C) Organic acid metabolism disorder
U D) Renal tubular acidosis
E) X-linked leukodystrophy

Answer 13

C. Page 82 and 85 FA2019. Page 85 of FA2020.
This patient has hyperammonemia. Everything else is alright though.
This is most likely some organic acid metabolism issue. There are plenty, like propionic acidemia, methylmalonic acidemia, etc.

In methylmalonic acidemia patients have hypoglycemia (accumulation of methylmalonate inhibits gluconeogenesis), ketosis (to make up for
hypoglycemia), and hyperammonemia (accumulation of methylmalonate inhibits the urea cycle).

Question 14

A 55-year-old woman is brought to the physician by her husband because of a change in behavior during the past 2 days. Her husband says, “Yesterday, she didn’t recognize a
picture of her own mother.” Neurologic examination shows that she has an inability to recognize objects unless she touches them or hears the sound that they make. These findings
most likely indicate a lesion involving the area supplied by which of the following arteries?
A) Anterior cerebral
B) Anterior choroidal
C) Lenticulostriate
D) Posterior cerebral
E) Thalamoperforating

Answer 14

D.
The patient is clearly having difficulty with visual association. She is seeing things but not sure what it is related to until touching it.
This is prosopagnosia due to a PCA stroke. Since its a visual problem for the most part, but neurologic exam is fine otherwise, you can choose PCA.

ACA has loss of sensation and paralysis in legs, while MCA has loss of sensation and paralysis in the face and arms.
Lenticulostriate is related to the striatum and internal capsule and often has lacunar infarcts due to hypertension. Would just have paralysis.
Anterior choroidal would have loss of sensation and paralysis also.

Question 15

A 24-year-old woman who has diffuse toxic goiter (Graves disease) undergoes a partial thyroidectomy. Several months later, she develops muscle cramps, tetany, and
hypocalcemia. Which of the following sets of laboratory findings in serum is most consistent with these findings?
Parathyroid
Phosphate Hormone 25-Hydroxyvitamin D
A) I l D
B) l D normal
C) l D D
D) D l normal
E) D D D

Answer 15

B. Page 330/360 discusses PTH. Page 341/373 discusses PTH disease.
This patient’s parathyroid glands were probably removed along with the thyroidectomy.
PTH is phosphate trashing hormone, so without PTH the phosphate will be high. PTH is obviously gonna be low.
Vitamin D is not related to PTH levels.

Question 16

A 56-year-old man has a 3-year history of progressive memory loss followed by aphasia, visuospatial disorientation, and inappropriate behavior. His father died in a nursing home at
age 65, 6 years after the onset of progressive dementia. His 55-year-old brother has had some difficulty remembering recent events and recalling familiar names. The patient dies 5
years after the onset of these symptoms. At autopsy, examination of the brain shows cerebral atrophy, predominantly in the mesial temporal and parietal cortices; in these areas
there are neurofibrillary tangles, neuritic plaques, and marked neuronal loss. This disorder most likely indicates a mutation in a gene encoding for which of the following molecules?
A) Amyloid A protein
B) ~2-Microglobulin
u C) Neurofilament protein
U D) Presenilin

Answer 16

D. Page 508/568.
This patient has the familial form of Alzheimer’s disease (neurofibrillary tangles of tau protein, neuritic plaques of beta amyloid,
and neuronal loss due to cortical atrophy). The familial form is due to presenilin1 and 2 as well as APP.

Question 17

A 60-year-old woman is receiving cisplatin therapy for advanced transitional cell bladder cancer. She develops paresthesias, and the medication
is stopped. The medication likely damaged the largest cells in the region labeled “B” in the drawing of the spinal cord shown. The damage to
these cells would most likely lead to which of the following motor signs?
A) Babinski sign
B) Clonus
U C) Fibrillations
0 D) Hyporeflexia
U E) Muscle atrophy

Answer 17

D. Page 518/601.
Area B is the dorsal root ganglion.
This area carries afferents.
This is basically what you check for with the knee jerk.
Hence, that reflex would be missing in severe DRG

Question 18

A 30-year-old woman comes to the physician for follow-up treatment of chronic renal failure and normocytic, normochromic anemia. Following the administration of recombinant
human erythropoietin, her hemoglobin concentration increases in part due to increased activity of 5-aminolevulinic acid (o-ALA) synthase in erythrocytes. This enzyme regulates the
reaction involving the condensation of which of the following compounds?
A) Acetate and hexacarboxylic porphyrinogen
B) Ferrous ion and protoporphyrin
C) Glycine and succinyl CoA
D) Lysine and o-ALA
E) Zinc and porphobilinogen

Answer 18

C. Page 417/461.
Very straightforward question about heme synthesis.
The first step involving ALA synthase makes ALA by combining glycine and succinyl-CoA.

Question 19

Forty of 100 attendees at a company Christmas party develop explosive, watery diarrhea followed by abdominal cramps and vomiting 12 to 48 hours after the party. About half of the
affected individuals also had headache. All of the affected individuals reported feeling better within several days. All of the affected individuals, and 6 of the 60 unaffected individuals,
consumed raw oysters. There was no other significant association between the consumption of specific foods and symptoms. Which of the following is the most likely causal
organism?
A) Bacillus cereus
B) Campy/obacter jejuni
C) Clostridium pertringens
D) Staphylococcus aureus
E) Vibrio parahaemolyticus

Answer 19

E. Page 146/148.
V cholerae other V vulnificus as well as V parahaemolyticus are all related to consumption of undercooked seafood like shellfish or oysters.

B cereus is related to reheated rice and usually causes vomiting but can also cause diarrhea within 8-18 hours.
C jejuni is related to undercooked meat or contact with animals. Plus this causes bloody diarrhea.
C perfringens is related to food left standing, allowing the spores to germinate and create heat-labile enterotoxin. Gas gangrene is a complication.
S aureus is related to mayonnaise and dairy products and would have rapid onset diarrhea.

Question 20

A 19-year-old man has had weakness of the muscles of his neck and extremities for the past week. Bladder and bowel function is normal. Position sense is impaired. Which of the
following is the most likely diagnosis?
CJ A) Amyotrophic lateral sclerosis
B) Parkinson disease
C) Poliomyelitis
U D) Polyneuropathy
E) Syringomyelia

Answer 20

D. Page 518/578.
This question is simply a matter of eliminating the other choices.
ALS would have no sensory or bowel/bladder deficits, so this was an excellent bait. However, ALS is not about weakness of muscles.
ALSO has UMN and LMN degeneration that causes a large array of symptoms, not just neck and extremity muscle weakness.
Parkinson is irrelevant in this question. Patient would have tremor or rigidity.
Poliomyelitis is irrelevant (pg 19/579). This would present with asymmetric LMN weakness and respiratory failure.
Syringomyelia is irrelevant. Patient would have symmetrical loss of pain and temperature in the cape distribution.

Question 21

A 72-year-old woman with coronary artery disease comes to the physician because of a 2-month history of progressive angina symptoms with exertion. Five months ago, the patient
underwent stent placement for significant stenoses of the proximal anterior interventricular (left anterior descending) and right coronary arteries. She remained symptom-free for
3 months. Her pulse is 76/min and regular, and blood pressure is 135/85 mm Hg. An ECG at rest shows no abnormalities; an exercise stress test shows ST-segment changes in
leads II, Ill, and aVF. Which of the following is the most likely cause of this patient’s recurrent angina symptoms?
A) Aneurysm of the right coronary artery
B) Dissection of the right coronary artery
u C) Neointima formation in the right coronary stent
U D) Thrombosis of the right coronary stent
E) Vasospasm in the stented right coronary artery

Answer 21

C. Page 304/330.
Not the worst question but definitely intimidating due to lack of experience with such a case.
The patient had RCA stenosis that was dealt with and she was fine for 3 months.
Something must have been going on in those 3 months because then she started a 2 month period of angina with exertion.
Its like her RCA stenosis came back again! And only choice C fits that explanation.
Choices A and B fail because she is fine when at rest. Same for choices D and E.
Restenosis occurs from gradual narrowing of the stent lumen due to neointimal proliferation.
This is why patients are put on a regiment of antiplatelet therapy after stent placement.

Question 22

A 63-year-old woman develops flank pain, tachycardia, and hypotension while receiving a blood transfusion in the intensive care unit. Her urine is wine-colored. Which of the
following is the most likely cause of these findings?
CJ A) ABO incompatibility
B) Bacterial contamination of the transfused blood
C) Extravascular hemolysis
U D) Immediate (type I) hypersensitivity reaction
E) Rh incompatibility

Answer 22

Page 114 FA2019.
Quesiton 37 was the one about transfusion related acute lung injury.
This patient here has the acute hemolytic transfusion reaction due to ABO incompatibility.
This is a type 2 HSR (antibodies and antigens) not a type 1 (allergic/anaphylactic).

Question 23

A 55-year-old woman comes to the physician for a routine health maintenance examination. She has never smoked cigarettes. Physical examination shows no abnormalities. A
chest x-ray shows a 2-cm left pulmonary nodule (coin lesion). Microscopic examination of the excised lesion shows nests and cords of regular cells with uniform round nuclei and
rare mitoses. Focally, the cells are arranged in trabeculae, and scattered rosettes are seen. Electron microscopy shows dense-core, membrane-bound granules in the cytoplasms of
these cells. These cells are most likely to closely resemble which of the following types of normal respiratory tract cells?
A) Alveolar capillary endothelial cell
B) Alveolar macrophage
u C) Chondrocyte
U D) Ciliated columnar epithelial cell
E) Goblet cell
0 F) Neuroendocrine cell
u G) Squamous epithelial cell
H) Type I pneumocyte

Answer 23

F. Page 689/767 FA2019.
This patient never smoked and is a female, so that fits the profile for adenocarcinoma.
The incidental finding of her coin lesion (rather than her presenting because of unexplained weight loss and cough) fits the profile for a hamartoma.

The microscopic examination is diagnostic. The rosettes are almost always indicative of a neuroendocrine turmor.
They are most likely referring to a bronchial carcinoid tumor. The question did not want a precise diagnosis anyway so its not 100% clear.

Question 24

A 40-year-old man who recently immigrated to the USA from Kenya is brought to the emergency department because of a 3-week
history of diarrhea. He appears disoriented and cachectic. He recalls zero of three objects after 5 minutes. A photograph of the head,
neck, and upper chest is shown. Similar findings are seen over the dorsal aspects of the hands. The diagnosis of a vitamin deficiency
is made. The deficient vitamin in this patient is part of a cofactor that contains which of the following components?
A) Adenine
B) Alanine
C) Apolipoprotein
D) Arachidonic acid
E) Aspartate

Answer 24

A. Page 67.
This is clearly an extreme presentation of the “Casal necklace” rash that occurs in the C3/C4 dermatome.
This patient has vitamin B3 deficiency. Niacin is a part of NAD. The A is adenine.

Question 25

A 64-year-old man undergoes surgical repair of an abdominal aortic aneurysm. During the repair, the left testicular artery is ligated. Anastomotic supply from which of the following arteries will maintain adequate arterial supply to the left testis in this patient? CJ A) Artery of the ductus deferens B) Inferior vesical artery C) Obturator artery U D) Posterior scrotal artery E) Superficial circumflex iliac artery

Answer 25

A. Page 610/686. This artery was previously tested in some NBME as the deferential artery. You can answer this question by simply thinking of what other artery would be able to supply the testis. The other arteries labelled do not reach the testis.

Question 26

A full-term male newborn has lethargy, poor feeding, and vomiting 48 hours after delivery. He appears flaccid. Serum studies show increased concentrations of ammonia and orotic acid. Which of the following labeled steps in the metabolic pathway is the most likely cause of these findings?

Answer 26

C. Page 82 and 83 FA2019. This is a straightforward question on OTC deficiency. High orotate and hyperammonemia with a low BUN. The excess carbamoyl phosphte upregulates pyrimidine synthesis, forming excess orotate.

Question 27

A researcher hypothesizes that exposure to more than 50 µg/L of arsenic in drinking water is associated with an increased risk for development of a common cancer compared with persons whose drinking water contains less than 5 µg/L of arsenic. Which of the following is the most time-efficient experimental design to investigate this hypothesis? CJ A) Case-control study B) Case series study C) Cohort study U D) Open-label, dose-ranging study E) Randomized, double-blind, controlled trial

Answer 27

A. Page 256/266. Classic NBME trash. The question asks for a time-efficient, experimental design. While case-control studies are time-efficient, they are observational studies. You would need a case (people drinking high arsenic) and control (people with no arsenic). Experimental studies are usually randomized controlled trials, where E would be the best answer

Question 28

A 4-year-old girl is brought to the physician because of a 6-month history of foul-smelling stools and failure to gain weight appropriately. She is at the 3rd percentile for height and weight. Abdominal examination shows distention. Stool analysis shows an increased fat concentration. Serum concentrations of anti-endomysial and anti-tissue transglutaminase antibodies are increased. Which of the following findings in the gastrointestinal tract is the most likely cause of the disorder in this patient? A) Eosinophilic infiltration of the mucosa of the small intestine B) Erosions of epithelial cells in the small intestine C) Lactase deficiency D) Periodic acid-Schiff (PAS)-positive granules in macrophages in the lamina propria of the small intestine E) Villous atrophy

Answer 28

E. Page 375/416. This patient's serum antibodies are diagnostic of Celiac disease. The answer choice was very easy. A -- Probably some parasitic infection. B -- Erosions are irrelevant. Small intestine erosion is related to IBD. C -- Irrelevant. D -- Whipple disease.

Question 29

A 28-year-old man with AIDS has fever, headache, and lethargy. Examination shows papilledema and nuchal rigidity. A mucicarmine stained smear of his cerebrospinal fluid is shown. Which of the following is the most likely primary site of infection with this organism? A) Eyes B) Gastrointestinal tract C) Lungs CJ D) Middle ear E) Skin

Answer 29

C. 153/155. This was the best answer to pick given the image and patient's AIDS history. This image shows budding but it is not broad-based, its narrow budding. Crypto is stained with india ink or mucicarcmine and can also be found with latex agglutination. This is a heavily encapsulated yeast that causes meningitis, encephalitis, and cryptococcosis. Patients inhale this so its found in the bronchoalveolar lavage.

Question 30

A 70-year-old man is brought to the emergency department because of a 1-week history of progressive shortness of breath with mild exertion, cough, fatigue, and weakness. The shortness of breath frequently awakens him from sleep and is partly relieved by sitting or standing. He has a 20-year history of hypertension treated with diuretics and ACE inhibitors; however, he does not always take his medications. His pulse is 85/min, respirations are 20/min, and blood pressure is 180/110 mm Hg. Crackles are heard on auscultation. A chest x ray shows cardiomegaly. Echocardiography shows decreased left ventricular systolic function. Which of the following patterns best characterizes this patient's cardiovascular variables at this time? Left Ventricular Stroke End-Diastolic Cardiac Volume Volume Output 0 A) i i i B) i i D C) i D i D) i D D E) D i i F) D i D G) D D i H) D D D

Answer 30

F. Page 306/332. This patient clearly has left heart failure. The fact that the x ray shows cardiomegaly and auscultation reveals crackles, it is decompensated. He has orthopnea, paroxysmal nocturnal dyspnea, and the pulmonary edema. Since the heart is not working well, obviously stroke volume and cardiac output will be low. The blood remains in the heart so his EDV will be high.

Question 31

A 24-year-old woman at 28 weeks' gestation is brought to the emergency department because of a 3-hour history of shortness of breath. She has asthma, but she currently takes no medications. Her pulse is 100/min, respirations are 32/min, and blood pressure is 120/83 mm Hg. Physical examination shows the use of accessory muscles of respiration. Diffuse inspiratory and expiratory wheezes are heard. An inhaled ~2-adrenergic agonist is administered. Which of the following findings is most likely in this patient after this therapy? A) Bradycardia B) Diaphoresis C) Dry mouth D) Pallor E) Tremor

Answer 31

E. Page 672/772. It is straight from the book. No reason to pick A, beta 2 might cause vasodilation but not bradycardia. Diaphoresis and dry mouth are muscarinic effects. Think about the fact that beta blockers help treat essential tremor and can mask the tremor of hypoglycemia. So a beta agonist must be capable of causing tremors

Question 32

A 4-year-old boy is brought to the emergency department by his mother 6 hours after she noticed that his urine was red. He is otherwise feeling well. Fifteen days ago, the patient had a sore throat, fever, and cough. His mother thought he had the flu and treated him symptomatically with rest and analgesics, and his status improved until now. His temperature is 38.5°C (101.3°F), pulse is 110/min, respirations are 22/min, and blood pressure is 100/50 mm Hg. Physical examination shows normal breath and cardiac sounds, no organomegaly, and 1 + lower extremity edema, bilaterally. Laboratory studies show: Which of the following is the most likely diagnosis? A) Membranous nephropathy B) Minimal change disease C) Papillary necrosis D) Proliferative glomerulonephritis E) Tubulointerstitial nephritis

Answer 32

D. Page 582/653 and page 591/664. This 4yo kid most likely had a Strep infection and now has PSGN. The only GN answer choice is D. Choices A and B are nephrotic so they are wrong. Choice E is basically acute interstitial nephritis and choice C is a papillary problem (not glomerular). Those two choices are related to various medications or conditions that are irrelevant here.

Question 33

The 35-year-old woman indicated by the arrow has a family history of retinitis pigmentosa. Which of the following modes of inheritance can be eliminated based on this pedigree? A) Autosomal dominant B) Autosomal recessive C) Multifactorial D) X-linked recessive

Answer 33

D. Page 59 FA2019. Men pass their Y chromosome to sons, so there definitely is not X-linked inheritance here since all men are having it.

Question 34

A 10-year-old girl with a lifelong history of intermittent dyspnea is brought to the physician for a follow-up examination. During an episode of dyspnea, she turns blue. The episode resolves after she squats. A systolic murmur was heard at birth. Today, a grade 4/6 systolic murmur is heard at the pulmonic area, radiating widely to the back and left side. Cardiac catheterization shows: Location Pressure (mm Hg) 02 Saturation Aorta 120/80 82% Vena cava 610 70% Pulmonary artery 20/8 70% Right atrium 4 70% Left atrium 6 95% Right ventricle 120/6 70% Left ventricle 120/6 82% Which of the following is most likely in this patient? U A) Diastolic murmur B) Enlarged left ventricle on chest x-ray 0 C) Hypervascular lung fields on chest x-ray D) Palpable right ventricular lift E) Pulsating aortic mass on CT scan of the chest

Answer 34

D. Page 297/321 FA2019. The patient clearly has a VSD. Remember my "VAPE later" mnemonic. Squatting increases pressures in the right heart, sending blood back into the LV and allowing the blood to then go into the aorta, fixing the cyanosis. A VSD would cause a systolic murmur whenever the LV contracts, cuz itll send blood into the RV. This is given in the question. Lung problems are usually a problem related to the left heart. Pulsating aortic mass would be maybe related to aortic issues not a VSD.

Question 35

A 10-year-old girl is scheduled to undergo fixation of a right femoral fracture. A neuromuscular blocking agent is administered prior to insertion of an endotracheal tube. Subsequently, she develops severe muscle rigidity. Her temperature is 41.1°C (106°F), pulse is 100/min, and blood pressure is unstable. Which of the following drugs most likely caused this reaction? A) Etomidate B) Midazolam C) Nitric oxide D) Nitrous oxide E) Rocuronium F) Succinylcholine

Answer 35

F. Page 537/599. Muscular blockade, leading to fever and muscle rigidity? Malignant hyperthermia. Classic presentation. Treat with dantrolene.

Question 36

A 71-year-old man is brought to the emergency department because of the sudden onset of dysarthria, dysphagia, and dizziness. Examination shows markedly decreased pain sensation on the right side of the face and complete loss of pain sensation on the left side of the body. The most likely cause is occlusion of which of the following labeled blood vessels in the normal brain stem shown?

Answer 36

D. Page 502/562 FA2019. https://www.youtube.com/watch?v=A8S3B9p1t_g This is Wallenberg syndrome. "Dont PICA (pick a) horse that cannot swallow." The patient has dyshphagia and some sensory deficits. The only label pointing at something posterior is D

Question 37

A 25-year-old woman at 16 weeks' gestation comes to the physician for a routine examination. One year ago, she had a serum thyroxine (T 4) concentration of 8.2 µg/dl and a serum thyroid-stimulating hormone (TSH) concentration of 2.1 µU/ml. At that time, she was not taking any medications and she was not pregnant. At this visit, serum T 4 concentration is 13.2 µg/dl and serum TSH concentration is 2.2 µU/ml. Which of the following is most likely responsible for the increased serum T 4 concentration in this patient? A) Diffuse toxic goiter (Graves disease) B) High T 4 content in prenatal vitamins C) Increased fetal production of T 4 D) Increased hepatic production of T 4-binding globulin E) Struma ovarii F) TSH-producing pituitary tumor

Answer 37

D. Page 331/361. This kind of presentation of abnormal T4 concentrations where a patient is presenting with labs or symptoms that seem like a thyroid imbalance is special in cases of pregnancy, OCP use, hepatic falure, steroid use, or nephrotic syndrome. This is basically a question of thyroid binding globulin, which is high in pregnancy and OCP use (estrogen increases TBG production. The globulin is holding on to all the thyroid, creating a scenario of hypothyroidism so the body has more TSH formation but inactive T3 and T4. The other answer choices are irrelevant.

Question 38

An 80-year-old woman comes to the physician because of a 1-month history of intermittent headaches and aching pain in her jaw while chewing. She has no history of similar headaches or pain. Neurologic examination shows no focal findings. Which of the following is the most appropriate next step in establishing the diagnosis? CJ A) Determination of erythrocyte sedimentation rate B) Leukocyte count C) Chest x-ray U D) MRI of the brain E) Cerebrospinal fluid analysis

Answer 38

A. Page 310/338. If a patient presents like this, it is important to know what tests to order even for CS and of course in real life. This is a patient with headaches and jaw pain, which should immediately ring a bell for "jaw claudication" of giant cell temporal arteritis. This patient should be started on prednisone asap before results of ESR return, because this can lead to irreversible blindness via opthalmic artery

Question 39

A 26-year-old man and his 25-year-old wife come to the physician for genetic counseling prior to conception. Both of the patients were previously found to have microcytic anemia and an increased fraction of hemoglobin A2. Genetic analysis shows that the man has a heterozygous null mutation of the B-globin gene, and the woman has a heterozygous mutation known to cause a 50% decrease in B-globin gene function of one allele. Which of the following best represents the B-globin function possibilities for this couple's offspring? A) All will have decreased B-globin function and transfusion-dependent anemia B) One in four will have less than 10% B-globin function and transfusion-dependent anemia C) One in four will have 25% B-globin function and may require occasional transfusions D) One in two will have 50% B-globin function without need for transfusions E) One in two will have normal B-globin function without need for transfusions

Answer 39

C. Page 410/454. Pretty clever question for a topic that is not really inherited in a standard pattern. The punette square makes it very simple. You can cancel out choices D and E because for D, with 50% beta globin you will need transfusions, and choice E says half the kids will be 100%, which is unlikely given that the father has a null mutation and the mother has mutation too, so then only a quarter of kids will be 100%. Not an easy or straightforward question unless you are confident and comfy with genetics and think of using one of the few genetics tools, the square.

Question 40

A 30-year-old man who is a migrant farm worker comes to the emergency department because of a 1-week history of fever, chills, and severe headache. He immigrated to the midwestern USA from Honduras 1 year ago. He is alert. His temperature is 40°C (104 °F), pulse is 101 /min, respirations are 20/min, and blood pressure is 105/62 mm Hg. The lungs are clear. Cardiac examination shows no abnormalities. The abdomen is soft with active bowel sounds. Neurologic examination shows a supple neck; there is no nuchal rigidity. He is oriented to person, place, and time. Laboratory studies show: Hemoglobin Hematocrit A) Anaerobic metabolism U B) Chloroquine resistance C) Exotoxin production D) Formation of hypnozoites E) Induction of adhesion molecules Leukocyte count Segmented neutrophils Lymphocytes Monocytes Urine Color Blood Urobilinogen 14 g/dL 42% 4600/mm3 57% 33% 10% clear yellow 1 + trace A photomicrograph of a peripheral blood smear is shown. This patient's overall condition is most likely caused by an infectious agent with which of the following features?

Answer 40

D. Page 157/162. Source of image --> http://spot.pcc.edu/~jvolpe/b/bi234/lec/2_parasites/images/P._vivax.htm This is Schuffner stippling due to Plasmodium vivax. In general you see something like this you immediately think of Plasmodium. It could be Chloroquine resistant (an answer choice that should make you think of Plasmodium), but not necessarily. He must have had hypnozoites before he came to the US a year ago.

Question 41

A 55-year-old man is brought to the emergency department because of a 1-hour history of severe chest pain, nausea, and vomiting. He is agitated, clammy, and sweating profusely. His temperature is 36.?°C (98°F), pulse is 130/min, respirations are 36/min, and blood pressure is 85/45 mm Hg. Jugular venous pressure is 12 cm H2 0 and crackles are heard in the lung bases bilaterally. Which of the following hemodynamic changes is most likely in this patient? Pulmonary Capillary Wedge Cardiac Output Systemic Vascular Pressure Resistance U A) i i i U B) i l i u C) l l l D) l l i E) l i l

Answer 41

B. Page 307/335. The severe chest pain might be indicative of a potential MI or HF. The question gives everything needed to make the right choice but it is based on your knowledge of cardiovascular topics. The clammy, sweating patient with normal temp but low BP seems like a case of shock. More specifically, this must be cardiogenic shock (not septic because of normal temp, no infection). Since the patient has crackles in the lung, blood must be backing up and pressures must be high in PCWP. This immediately brings you to A & B. However, PCWP can be high or low in cardiogenic or obstructive shock based off of the specific issue causing the shock. Recall that the only shock where SVR is low is distributive shock, so you know for SURE that SVR must be high. I speak in my book about how no matter what shock we discuss, the underlying physiology is always based off of CO x SVR = MAP. In distributive, SVR is very low so CO tries to be increased to maintain MAP. In other shocks, SVR is high and CO is low, which brings us to choices B and D. 50% chance of guessing right. Figuring out whether PCWP would be high or low comes from what i initially said, the normal crackles in the lung. This patients JVP is high due to poor forward-flow of blood in this patients specific case. So their PCWP must be high too for the same poor forward-flow. If the infarct were only on the right heart, blood would back up and the JVP would be even higher and not much blood would make it to the left heart so the PCWP would be low in that case. But most cardiogenic shock cases have infarct of both sides of the heart.

Question 42

A 34-year-old woman with a long history of rheumatoid arthritis refractory to treatment with corticosteroids and methotrexate comes to the physician because of a 2-week history of increasingly severe low back pain, decreased appetite, and malaise. She has never had low back pain in the past. She has not had fever, lower extremity weakness, constipation, bladder or bowel incontinence, weight loss, or sensory changes. Six weeks ago, she began treatment with infliximab because of bilateral wrist, hand, and knee pain. Her temperature is 37°C (98.6°F). Physical examination shows mild tenderness over the L 1-2 vertebrae. Laboratory studies show: Hemoglobin Hematocrit Leukocyte count Platelet count 11.3 g/dL 32% 7800/mm3 290,000/mm3 An MRI of the spine shows osteomyelitis of L 1-2 with destruction of the intervertebral disc space and a 1.2-cm adjacent abscess. The abscess is debrided, and samples of the abscess and bone tissue are sent for analysis. A Gram stain is negative. Pathologic examination of the bone specimen shows acute and chronic inflammation with granuloma formation. Which of the following is the most likely cause of these findings? A) Ankylosing spondylitis U B) Multiple myeloma C) Progression of rheumatoid arthritis () D) Sarcoidosis E) Tuberculous osteomyelitis

Answer 42

E. Page 122 for TNF, and page 140/141 of FA2019 for TB. First of all, choices A-D make no sense. Second, remember your TNF alpha inhibitors. This patient started infliximab, which is one of the "In Ada Ce Goli" meds from the Hindi mnemonic I made. The mnemonic says "In Ada Ce Goli marti, totally not fair." It is a corny phrase from an old Indian song. It means you're shooting at me with your beauty, totally not fair. Something like that but it gets the job done. Totally Not Fair is for TNF. The patient must have latent TB that was previously locked in the granuloma. With the TNFa inhibitor, that granuloma got weak and the TB reactivated. Now she has Potts. Disseminated TB causing osteomyelitis. And TB, Mycoplasma, is acid fast so it does not gram stain.

Question 43

A 32-year-old woman comes to the physician because of a 7-day history of sneezing, nasal stuffiness, and watery eyes. She has a history of similar symptoms each spring while gardening. Her temperature is 37°C (98.6°F). Which of the following types of cells are most likely to be increased in her nasal secretions as a result of this reaction? CJ A) Basophils B) Eosinophils C) Lymphocytes U D) Mast cells E) Monocytes

Answer 43

B. Page 400/444 for eosinophils, and page Great question. Tough choices. Read the question carefully. They want the result of this reaction. The reaction itself is initiated by mast cell degranulation (allergies). Mast cells release many things and the histamine and eosinophil chemotactic factors are crucial. The result is from later activity by eosinophils, which are activated by IL5. There is IgE clustering and cross linking. Type 1 HSR.

Question 44

Immediately after a spontaneous vaginal delivery, a full-term male newborn is found to have a tuft of hair on the midline in the lumbar region. Palpation of the area shows an absence of spinous processes in that region. Imaging studies show no additional abnormalities. The most likely cause of this defect was failure of which of the following events during gestation? A) Development of the notochord B) Formation of the neural tube C) Formation of the yolk sac D) Fusion of the sclerotomes E) Migration of the neural crests

Answer 44

D. Page 479/537 of FA2019. Witty NBME wording. The tuft of hair and lack of spinous processes is diagnostic of SBO. Patient has Spina bifida occulta which is a neural tube defect (failure of fusion of the neuropores). Sclerotomes are the part of each somite in a vertebrate embryo giving rise to bone or other skeletal tissue. Since a part of this patient's spina bifida included "absense of spinous processes" then a sclerotome was involved. Knowing that neural tube defects are an issue with fusion should be enough to get to the right answer. Choices A and B are nonsense because of the notochord or neural tube did not develop/form, the entire CNS would not form. The yolk sac has nothing to do with this scenario. Neural crest migration is a bait but it is irrelevant to neural tube defects. Sclerotomes -> vertebrae, rib cage, occipital bone (part) Myotomes -> skeletal muscle of the back, ribs, limbs Syndetomes -> cartilage, tendons Dermatomes -> skin of the back

Question 45

An investigator is studying a new drug for the treatment of patients undergoing adjuvant radiation therapy. The drug is designed to be administered prior to irradiation to minimize localized tissue damage at the irradiated site. This drug most likely inhibits which of the following effects of external beam radiation? CJ A) Depurination B) DNA ligase inactivation C) DNA polymerase activation U D) Formation of pyrimidine dimers E) Free radical formation F) Tautomerization