1.
A 28 year old woman comes to the physician for a health maintenance examination. During the interview, she tearfully tells the physician that she and her new husband are having problems. She says she wants to go out with friends, but he does not enjoy being with people, referring individual activities such as hiking. She says he seems indifferent to sexual intimacy and neither shows much emotion nor understands her feelings at all. Which of the following personality styles best explains the husband’s behavior?
Correct Answer
D. Schizoid
Explanation
SCHIZOID describes people who are uninterested in social attachment.
SCHIZOTYPAL people have both diminished capacity for relationships and peculiar patterns of thought, including magical thinking, odd beliefs, odd perceptual experiences, and subtle, low grade abnormalities of thought form.
Mistrust, projection, and the attribution of malevolence are all elements of PARANOIA, which may be either psychotic, implying a break from reality, or nonpsychotic, as in personalty disorder.
2.
A 55-year-old woman is scheduled to undergo transvaginal hysterectomy and oophorectomy for dysfunctional uterine bleeding. During the procedure, the uterus must be separated from all surrounding pelvic structures. Identification and incision of which of the following structures that attaches to the cervical region and extends posteriorly is most appropriate in this patient?
Correct Answer
F. Uterosacral ligament
Explanation
UTEROSACRAL LIGAMENT,
a ligament that extends from the cervix to the posterior pelvic wall. It is thought to help stabilize the uterus in the pelvic cavity
3.
A 27-year-old woman comes to the physician because of a 2-year history of sporadic vision and a 1 year history of intermittent numbness and tingling in her arms. The symptoms became more severe 5 days ago after a 4-day visit from her husband’s parents. During the past year, she also has had four episodes of urinary incontinence. Physical examination shows mild dysarthria. On mental status examination, she has a mildly worried mood and a reactive affect. MRI of the brain shows a few small, scattered, nonspecific white-matter plaques. Which of the following is the most likely diagnosis?
Correct Answer
D. Multiple sclerosis
Explanation
MS is approximately threefold more common in women than men. The age of onset is typically between 20 and 40 years (slightly later in men than in women), but the disease can present across the life span.
The onset of MS may be abrupt or insidious. Symptoms may be severe or seem so trivial that a patient may not seek medical attention for months or years. Indeed, at autopsy, approximately 0.1% of individuals who were asymptomatic during life will be found, unexpectedly, to have pathologic evidence of MS. Similarly, in the modern era, an MRI scan obtained for an unrelated reason may show evidence of asymptomatic MS. Symptoms of MS are extremely varied and depend on the location and severity of lesions within the CNS. Examination often reveals evidence of neurologic dysfunction, often in asymptomatic locations. For example, a patient may present with symptoms in one leg but signs in both.
MRI has revolutionized the diagnosis and management of MS; characteristic abnormalities are found in >95% of patients although more than 90% of the lesions visualized by MRI are asymptomatic. An increase in vascular permeability from a breakdown of the BBB is detected by leakage of intravenous gadolinium (Gd) into the parenchyma. Such leakage occurs early in the development of an MS lesion and serves as a useful marker of inflammation. Gd enhancement persists for approximately 1 month, and the residual MS plaque remains visible indefinitely as a focal area of hyperintensity (a lesion)
Relapsing/remitting MS (RRMS) accounts for 85% of MS cases at onset and is characterized by discrete attacks that generally evolve over days to weeks (rarely over hours). There is often complete recovery over the ensuing weeks to months. However, when ambulation is severely impaired during an attack, approximately half will fail to improve. Between attacks, patients are neurologically stable.
Weakness of the limbs may manifest as loss of strength, speed, or dexterity, as fatigue, or a disturbance of gait. Exercise-induced weakness is a characteristic symptom of MS. The weakness is of the upper motor neuron type and is usually accompanied by other pyramidal signs such as spasticity, hyper-reflexia, and Babinski's signs. Occasionally a tendon reflex may be lost (simulating a lower motor neuron lesion) if an MS lesion disrupts the afferent reflex fibers in the spinal cord
Optic neuritis (ON) presents as diminished visual acuity, dimness, or decreased color perception (desaturation) in the central field of vision. These symptoms can be mild or may progress to severe visual loss. Rarely, there is complete loss of light perception. Visual symptoms are generally monocular but may be bilateral. Periorbital pain (aggravated by eye movement) often precedes or accompanies the visual loss. An afferent pupillary defect is usually present. Funduscopic examination may be normal or reveal optic disc swelling (papillitis). Pallor of the optic disc (optic atrophy) commonly follows ON. Uveitis is uncommon and should raise the possibility of alternative diagnoses such as sarcoid or lymphoma.
4.
A 54 y/o woman comes to the physician because of a 5-day history of severe mid-back pain Physical examination shows point tenderness over the T6 vertebra. Serum studies show a
calcium concentration of 13.4 mg/dl; urinalysis shows Bence Jones proteins. Which of the following is the most likely cause of this patient’s hyper-calcemia?
Correct Answer
D. Local interleukin-1 (IL-1) and tumor necrosis factor effect
Explanation
The underlying disease is Multiple Myloma: Hypercalcemia in multiple myeloma, where there is bone marrow infiltration by tumor has been ascribed to the release of osteoclast activating factors by the tumor cells. Osteoclast-induced bone resorption may occur in discrete focal areas (lytic lesions) or throughout the skeleton. The high rate of bone resorption is associated with an absence of osteoblast-mediated bone formation, resulting in diffuse bone loss. The uncoupling of bone resorption and formation results from paracrine factors, which enhance osteoclast formation and activity and inhibit the capacity for marrow stromal cells to differentiate into osteoblasts. In multiple myeloma, various studies have implicated interleukin (IL)-6, RANKL (from TNF family), macrophage inflammatory protein 1a, osteoclast activating factor [aka IL-1], osteoprotegerin, and IL-3 as factors contributing to the development of lytic bone disease and hypercalcemia.
5.
During an experiment, a cuff occluder is placed on the left renal artery of a normal rat and inflated to cause a 90% decrease in the cross-sectional area of the artery. A catheter is placed in the left and right renal veins to sample the effluent. The concentration of which of the following substances will most likely be higher in the effluent from the left renal vein than that from the right renal vein
Correct Answer
E. Renin
Explanation
Answer: E) The test is simulating RAS (Renal Artery Stenosis). And the question is addressing your understanding of the RAAS. Juxtaglomerular (JG) cells associated with the afferent arteriole entering the renal glomerulus are the primary site of renin storage and release in the body. A reduction in afferent arteriole pressure (kidney thinks you are hypotensive - less blood going to kidney) causes the release of renin from the JG cells, whereas increased pressure inhibits renin release. So, in this scenario the Renin will be increased leaving the efferent of the Left Kidney as that is the Kidney affected by RAS. A) ADH is released from the posterior pituitary in response to increased renin and increases fluid retention. B) Aldosterone released from the Adrenal Cortex is caused by increase Renin. C) Endothelin (ET-1) is used to control local smooth muscle constriction Endothelial cells upregulate ET-1 in response to hypoxia, oxidized LDL, pro-inflammatory cytokines, and bacterial toxins D) Epinephrine is a sympathetic response and is produced by chromaffin cells in the Adrenal medulla.
6.
A healthy 21-year-old man dies suddenly of cardiac arrest after snorting cocaine. Cocaine-induced inhibition or which of the following is the most likely explanation for the cardiac arrest?
Correct Answer
F. NorepinepHrine reuptake
Explanation
CARDIOVASCULAR EFFECTS — The major cardiovascular effects of cocaine appear to be caused by the inhibition of norepinephrine reuptake into the synaptic cleft by sympathetic neurons [2]. Since reuptake is the major mechanism by which neurotransmitters are removed from active receptor sites, this inhibition results in potentiation of the response to sympathetic stimulation of innervated organs and to infused catecholamine. Cocaine may also enhance the release of catecholamines from central and peripheral stores [4]. The ensuing sympathomimetic actions (increased myocardial inotropy, heart rate, systemic blood pressure, and coronary artery constriction) are mediated by stimulation of the alpha- and beta adrenergic receptors and result in increased myocardial oxygen demand. (uptodate.com)
7.
A 30-year-old woman, gravida 2, para 2, develops severe vaginal bleeding immediately after vaginal delivery of a male newborn at tern.The hemorrhage continues during the next hour and the patient undergoes an emergency hysterectomy to control the bleeding. Examination of the uterus shows fragments of placenta adherent to the uterine wall. There is absence of the decidua basalis. Which of the following is the most likely diagnosis?
Correct Answer
D. Placenta accreta
Explanation
PATHOMA excerpt:
V. PLACENTA ACCRETA
A. Improper implantation of placenta into the myometrium with little or no
intervening decidua
B. Presents with difficult delivery of the placenta and postpartum bleeding
C. Often requires hysterectomy
8.
A healthy 22-year-old man is a subject in a study investigating the regulation of heart rate dung exercise. He is sitting on a stationary bicycle and is instructed to begin pedaling in 5 minutes. One minute before he begins to pedal, his heart rate increases. An increase in which of the following transmitters acting at the indicated receptor best explains the increase in heart rate in this man?
TRANSMITTER ------ RECEPTOR
A) Acetylcholine ------ muscarinic
B) Acetylcholine ------ nicotinic
C) Norepinephrine ------ a1
D) Norepinephrine ------ B1
E) Norepinephrine ------ B2
Correct Answer
D. D
Explanation
One minute before the man begins pedaling, his heart rate increases. This suggests that the increase in heart rate is due to the activation of beta-1 (B1) adrenergic receptors by norepinephrine. Norepinephrine is a neurotransmitter released by sympathetic nerves and acts on B1 receptors in the heart, increasing heart rate and contractility. Acetylcholine, on the other hand, acts on muscarinic receptors and would typically decrease heart rate. Therefore, option D, Norepinephrine acting on B1 receptors, best explains the increase in heart rate in this man.
9.
An 16-year-old woman with mild mental retardation is brought to the physician because of a 3-day history of decreased ability to see in reduced light. She has a lifelong history of chronic diarrhea. Two years ago. she developed a lack of muscle control of her arms and legs, and generalized weakness. Her 16-year-old brother has had similar symptoms. Ophthalmologic examination shows bilateral retinitis pigmentosa. There is ataxia and loss of deep tendon reflexes. Laboratory studies show erythrocytes with spiny projections and a serum total cholesterol concentration of '40mg/dL. Which of the following apolipoproteins is most likely deficient in this patient?
Correct Answer
C. Apo B
Explanation
The patient's symptoms, including retinitis pigmentosa, ataxia, loss of deep tendon reflexes, chronic diarrhea, and low serum cholesterol, are consistent with a diagnosis of abetalipoproteinemia. Abetalipoproteinemia is an autosomal recessive disorder characterized by a deficiency of apolipoprotein B (Apo B), which is required for the synthesis and secretion of chylomicrons and very low-density lipoproteins (VLDL). This deficiency leads to malabsorption of dietary fat and fat-soluble vitamins, as well as the accumulation of lipid droplets in enterocytes and hepatocytes. Therefore, the most likely deficient apolipoprotein in this patient is Apo B.
10.
Which of the following is NOT a component of the Glasgow Coma Scale (GCS)?
Correct Answer
D. Pupillary response
Explanation
The Glasgow Coma Scale (GCS) is a neurological scale used to assess a patient's level of consciousness. It consists of three components: eye opening, verbal response, and motor response. 1 Pupillary response, while an important neurological assessment, is not part of the GCS.
11.
A 49-year-old man with pancreatic cancer undergoes a Whipple procedure to resect the distal stomach, duodenum, and head of the pancreas. During the procedure, the cut and of the remaining stomach is joined to the side of the jejunum (gastrojejunostomy). Which of the following nerve structures can be cut to decrease stomach acid output and decrease the likelihood of ulcers forming in the jejunum at the site of junction with the stomach?
Correct Answer
F. Vagal trunks
Explanation
The vagus nerve splits into branches that go to different parts of the stomach. Stimulation from these branches causes stomach to produce acid. Too much stomach acid leads to ulcers that may eventually bleed and create an emergency situation. Vagotomy is performed when acid production in the stomach cannot be reduced by other means. Usually used when ulcers in the stomach and duodenum do not respond to medications and changes in diet. Although elective vagotomy has decreased, it is often performed in conjunction with gastrointestinal surgery, such as partial removal of the stomach as in this case. There are several types of vagotomies. Truncal vagotomy severs the trunk of the vagus nerve as it enters the abdomen. Parietal cell or proximal gastric vagotomy leaves the trunk intact, but severs the branches that go to different parts of the stomach.
Holla H.Z.
12.
A 40-year-old woman comes to the physician for genetic counseling because of a family history of muscle weakness. She says that she has not sought treatment because her symptoms are not severe, but her children have profound muscle weakness and fatigue. Sequence analysis of mitochondrial DNA shows a mutation in 50% of the mothers mitochondria DNA and in 100% of each other children's mitochondrial DNA. A pedigree is shown. Which of the following genetic principles best explains the findings in this family?
Correct Answer
C. Heteroplasmy
Explanation
Heteroplasmy best explains the findings in this family. Heteroplasmy refers to the presence of both normal and mutated mitochondrial DNA in an individual. In this case, the mother has the mutation in only 50% of her mitochondrial DNA, while her children have the mutation in 100% of their mitochondrial DNA. This explains why the mother's symptoms are not as severe as her children's, as the proportion of mutated DNA affects the severity of symptoms. This pattern of inheritance is consistent with heteroplasmy, making it the best genetic principle to explain the findings.
13.
A 52 year old man with a family history of renal failure comest to the physician because of abdominal pain over the last 6 months. He has been treated in the past for renal calculi and hypertension. Physical examination shows bilateral palpable masses in the upper abdomen. Urinalysis shows crenated erythrocytes and mild proteinuria. A CT scan of the abdomen identifies the cause of the patient’s problem. Which of the following is the most likely diagnosis?
Correct Answer
D. Polycystic kidney disease
Explanation
The patient's family history of renal failure, previous history of renal calculi and hypertension, and physical examination findings of bilateral palpable masses in the upper abdomen suggest a diagnosis of polycystic kidney disease. The presence of crenated erythrocytes and mild proteinuria on urinalysis further supports this diagnosis. A CT scan of the abdomen can confirm the presence of multiple cysts in the kidneys, which is characteristic of polycystic kidney disease. Adrenal adenoma, glomerulonephritis, Henoch-Schonlein purpura, and renal cell adenoma are less likely diagnoses based on the clinical presentation and findings.
14.
A 55-year-old man comes to the physician because of two episodes of painless, blood-tinged urine during the past week. His last episode was 2 days ago. He has smoked 1 pack of cigarettes daily for 35 years. Vital signs are within normal limits. Physical examination shows no abnormalities. Urinalysis shows normal findings except for microscopic blood. Which of the following is the most likely diagnosis?
Correct Answer
A. Bladder cancer
Explanation
The most likely diagnosis for this patient is bladder cancer. The patient's history of smoking for 35 years is a significant risk factor for bladder cancer. The painless, blood-tinged urine is a common symptom of bladder cancer. The normal physical examination and urinalysis findings, except for microscopic blood, further support this diagnosis. Bladder diverticulum, interstitial cystitis, nephrolithiasis, and urinary tract infection are less likely given the patient's presentation and risk factors.
15.
A previously healthy 6-year-old girl is brought to the emergency department because of severe abdominal pain, nausea, and vomiting that began 4 hours after attending a friend's birthday party. Cake and other pastries were served at the party. She appears acutely ill and mildly dehydrated. Her temperature is 37°C (98.6°F), pulse is 104/min, respirations are 20/min, and blood pressure is 96/60 mm Hg. Examination shows no abnormalities of the skin. Bowel sounds are hyperactive. Which of the following is the most likely cause of these findings?
Correct Answer
B. Enterotoxin ingestion
Explanation
The most likely cause of the girl's symptoms is enterotoxin ingestion. The symptoms of severe abdominal pain, nausea, and vomiting that began after attending a party where cake and other pastries were served suggest that the girl may have ingested food contaminated with enterotoxins. Enterotoxins are toxins produced by certain bacteria that can cause gastrointestinal symptoms such as abdominal pain, nausea, and vomiting. This is supported by the absence of abnormalities on skin examination and the presence of hyperactive bowel sounds, which are consistent with a gastrointestinal cause.
16.
A 39-year-old woman with end-stage renal disease caused by systemic lupus erythernatosus undergoes kidney transplantation from a living, unrelated donor. Despite aggressive immunosuppressive therapy, the transplant is rejected after 6 months. Analysis of a biopsy specimen of the transplant shows numerous infiltrating CD8+ T lymphocytes. Which of the following is the most likely cause of rejection of the transplant in this patient?
Correct Answer
C. Direct cytotoxicity
Explanation
The most likely cause of rejection of the transplant in this patient is direct cytotoxicity. This is suggested by the presence of numerous infiltrating CD8+ T lymphocytes in the biopsy specimen. CD8+ T lymphocytes are known to be cytotoxic and can directly kill cells. In this case, the CD8+ T lymphocytes are likely recognizing the transplanted kidney as foreign and mounting an immune response against it, leading to rejection. Antibody synthesis, complement activation, histamine release, and nitric oxide production are not the most likely causes of rejection in this scenario.
17.
A male newborn is delivered at 38 weeks' gestation following an uncomplicated pregnancy. Twelve-hours later, he begins sucking frantically and crying inconsolably. He overreacts to stimuli around him and has a marked startle response. The symptoms slowly resolve over the next 2 to 3 weeks. The most likely explanation for these symptoms is maternal use of which of the following substances during pregnancy?
Correct Answer
B. Heroin
Explanation
The symptoms described in the question, including frantic sucking, inconsolable crying, overreaction to stimuli, and a marked startle response, are consistent with neonatal abstinence syndrome (NAS). NAS occurs when a newborn is exposed to drugs in utero and experiences withdrawal symptoms after birth. Heroin is a potent opioid that can easily cross the placenta and cause NAS in newborns. Alcohol, LSD, marijuana, and psilocybin are not typically associated with the same withdrawal symptoms seen in NAS.
18.
A 22-year-old woman comes to the physician for a follow-up examination. One year ago, she was diagnosed with a pulmonary embolism. Two years ago, she delivered a female stillborn at 23 weeks' gestation. Physical examination today shows no abnormalities. Laboratory studies show a platelet count of 250,000/mm3, a prothrombin time within the reference range, and an increased partial thromboplastin time. The findings in this patient are most consistent with which of the following conditions?
Correct Answer
A. AntipHospHolipid antibody syndrome
Explanation
The patient's history of a pulmonary embolism and a stillborn delivery at 23 weeks' gestation suggests a history of thrombotic events. The increased partial thromboplastin time indicates a prolongation in the time it takes for blood to clot, which is a characteristic finding in antiphospholipid antibody syndrome. This syndrome is an autoimmune disorder characterized by the presence of antiphospholipid antibodies, which can lead to an increased risk of blood clots. The other options, including Factor V Leiden mutation, increased factor VIII concentration, protein C deficiency, and Prothrombin G20210A mutation, are all associated with an increased risk of thrombosis but do not fully explain the patient's clinical presentation.
19.
A 2-month-old boy dies of meningitis despite appropriate antibiotic therapy. Culture of his cerebrospinal fluid grows Mycobacterium tuberculosis. Two of his brothers died of atypical mycobacterial infections. Which of the following immunodeficiencies most likely explains this familial history?
Correct Answer
B. Interferon-y receptor deficiency
Explanation
The correct answer is Interferon-y receptor deficiency. This immunodeficiency impairs the body's ability to respond to interferon-y, which is important for the immune response against Mycobacterium tuberculosis. The familial history of atypical mycobacterial infections, including the death of two brothers, suggests a genetic immunodeficiency. Complement deficiency, leukocyte adhesion deficiency, and X-linked agammaglobulinemia are not associated with an increased susceptibility to mycobacterial infections.
20.
A 64-year-old woman comes to the physician because of a 6-month history of heartburn and difficulty swallowing solid food and liquid. She has not had nausea or vomiting. She also has a 2-year history of pain and swelling of her wrists and hands. She has not seen a physician in 5 years. She takes no medications. She does not smoke. Physical examination shows no wrinkles on the face and neck. Her vital signs are within normal limits. There is synovial thickening of the wrists bilaterally. A photograph of the left hand is shown. Abdominal examination shows no abnormalities. Which of the following sets of findings is most likely on esophageal manometry?
Esophageal Lower Esophageal
Peristalsis Sphincter Tone
A) Increased increased
B) Increased decreased
C) Normal increased
D) Normal decreased
E) Decreased increased
F) Decreased decreased
Correct Answer
F. F
Explanation
The correct answer is F) Decreased peristalsis, decreased lower esophageal sphincter tone. This is the most likely set of findings on esophageal manometry because the patient's symptoms of heartburn and difficulty swallowing solid food and liquid are consistent with a diagnosis of achalasia. Achalasia is characterized by impaired peristalsis and decreased lower esophageal sphincter tone, leading to difficulty in moving food down the esophagus and into the stomach. The patient's history of pain and swelling in her wrists and hands suggests an underlying autoimmune disorder, which can be associated with achalasia. The absence of wrinkles on the face and neck may be a clue to the diagnosis of systemic sclerosis, which can also be associated with achalasia.
21.
Question missing from original
Correct Answer
A. True
22.
A 36-year-old man comes to the physician for a routine examination. He has a 5-year history of recurrent episodes of genital herpes treated with acyclovir. He says, "I`ve been taking the medication, but I still occasionally get lesions. When will I be cured?" The physician informs him that herpes simplex is a lifelong infection, with no cure at the present time. Which of the following best explains the longevity of the herpes simplex virus?
Correct Answer
H. Establishment of a latent infection in sensory nerve cells
Explanation
The longevity of the herpes simplex virus is best explained by its establishment of a latent infection in sensory nerve cells. The virus can remain dormant in these cells for long periods of time, periodically reactivating and causing recurrent episodes of symptoms. This ability to establish latency allows the virus to persist in the body indefinitely, leading to a lifelong infection.
23.
A 24-year-old woman comes to the physician because of a 1-day history of pain in her left leg while walking Her temperature is 37°C (98.6°F), pulse is 84/min, and blood pressure is 135.78 mm Hg. Examination of the left lower extremity shows only a markedly decreased pulse in the left lower extremity. An intermittent faint diastolic heart murmur is heard at the apex. Angiography of the left lower extremity shows complete obstruction of the distal left femoral artery by what appears to be a thrombus. The occlusion is removed using a catheter. Microscopic examination of the removed specimen shows scattered mesenchymal cells in an abundant extracellular matrix. Echocardiography confirms a diagnosis of cardiac tumor. This patient most likely has which of the following types of cardiac tumors?
Correct Answer
E. Myxoma
Explanation
The patient in the scenario presented with pain in her left leg while walking, a decreased pulse in the left lower extremity, and a diastolic heart murmur. Angiography revealed complete obstruction of the distal left femoral artery by a thrombus, which was successfully removed. Microscopic examination of the removed specimen showed scattered mesenchymal cells in an abundant extracellular matrix. Echocardiography confirmed a diagnosis of cardiac tumor. Based on these findings, the most likely type of cardiac tumor in this patient is a myxoma. Myxomas are the most common primary cardiac tumors and can present with symptoms related to embolization, such as peripheral arterial occlusion.
24.
A 48-year-old manic brought to the emergency department because of difficulty opening his mouth and stiffness of his neck, shoulders, and back for 4 hours. He sustained a puncture wound to
his arm 1 week ago. He has received no medical care for 30 years. Physical examination shows trismus and opisthotonos. Which of the following best describes the process in this patient?
Correct Answer
A. Blockade of inhibitory neurotransmitter release
Explanation
This is a description of tetanus toxicity, which causes trismus (lockjaw) and opisthotonos (severe hyperextension leading to arching of the body).The mechanism of action of the tetanus toxin (tetanospasmin) is blocking the release of GABA (inhibitory neurotransmitter) and glycine at the neuromuscular junction.
25.
A 33-year-old woman comes to the physician because of a 16-kg (35-1b)weight gain during the past 6 months despite dieting. She is 168 cm (5 fl 6 in) tall and now weighs 114 kg (230 lb); BMI is 37 kg/m2. Her blood pressure is 156106 mm Hg. Physical examination shows a round, ruddy face with hirsutism, excess weight predominantly in the shoulders and abdomen: and purple striae over the abdomen. An MRI shows a mass in the pituitary gland. A CT scan of the abdomen shows enlarged adrenal glands. Which of the following histologic changes would be expected in this patient's adrenal glands?
Correct Answer
A. Cortical hyperplesia
Explanation
In this patient with a pituitary mass, the most likely diagnosis is Cushing's syndrome, which is characterized by excessive production of cortisol. Cortisol is produced by the adrenal glands, and in Cushing's syndrome, there is bilateral adrenal hyperplasia. This is reflected in the answer choice of "Cortical hyperplasia," which refers to the hyperplasia of the adrenal cortex. Cortical hypertrophy, cortical metaplasia, medullary hyperplasia, medullary hypertrophy, and medullary metaplasia are not typically seen in Cushing's syndrome.
26.
A mouse melanoma, B-16. is highly metastatic. A clone of the B-16 melanoma cells is injected intravenously into the tail vein of mice, and 3 weeks later tumor nodules are found in the lungs, liver, and ovaries. When an antibody to a liver cell surface antigen is injected 1 hour prior to injection of the B-16 melanoma cells, formation of tumor nodules in the liver is prevented, but tumor nodules develop in the ovaries and lungs. In vitro studies do not show any cytotoxic effect of the antibody on B-16 or hepatic cells. Which of the following processes is most likely to be affected by the antibody?
Correct Answer
A. Homing
Explanation
The antibody to the liver cell surface antigen prevents the formation of tumor nodules in the liver, but tumor nodules still develop in the ovaries and lungs. This suggests that the antibody is affecting the process of homing, which is the ability of cancer cells to migrate and establish themselves in specific organs. The antibody likely inhibits the binding of the B-16 melanoma cells to the liver cells, preventing their homing to the liver and subsequent tumor formation. However, it does not affect the ability of the cells to invade or migrate to the ovaries and lungs, as tumor nodules still develop in these organs.
27.
A study is conducted to assess the effectiveness of vitamin C in preventing common colds in children, Patients are randomly assigned to receive either vitamin C or no intervention. Outcome events (common cold) are reported by the parents on a monthly basis for 1 year. Results show that those taking vitamin C have fewer colds compared with those who received no intervention (p<0.05). Which of the following raises the most concern about the validity of the conclusion that vitamin C supplements prevent the common cold?
Correct Answer
D. Variability in outcome assessment
Explanation
The variability in outcome assessment raises the most concern about the validity of the conclusion that vitamin C supplements prevent the common cold. If there is a high degree of variability in how the outcome (common cold) is assessed by the parents, it could introduce bias and affect the accuracy of the results. This variability could lead to inconsistent reporting of colds, making it difficult to determine the true effectiveness of vitamin C in preventing the common cold.
28.
A 21-year-old African American man with sickle cell disease is brought to the emergency department 2 hours after the sudden onset of severe pain in his abdomen and knees, He has had six similar episodes within the past 4 years; he was admitted to the hospital each time for treatment of the pain. His course has been complicated by two episodes of pneumonia and a small cerebral infarction in the past 2 years. The patient asks the physician for extra pain medication to "kill me because I can't take it anymore." Which of the following initial actions by the physician regarding the patient's request is most appropriate?
Correct Answer
C. Reevaluate the patient after his pain has been controlled
Explanation
The most appropriate initial action by the physician regarding the patient's request for extra pain medication is to reevaluate the patient after his pain has been controlled. This is because the patient is experiencing severe pain due to sickle cell disease, which is a known complication of the condition. It is important to address the patient's pain and provide appropriate pain management. However, it is also important to assess the patient's overall condition and mental state once the pain has been controlled, as the patient's request for extra pain medication may be influenced by factors such as depression or emotional distress.
29.
A 7-year-old girl is brought to the physician by her parents because of a 3-year history of temper tantrums when her parents leave her, She refuses to sleep alone and recently would not attend her friend's birthday slumber party. She calls to her mother if she is in another room of the house. Each morning, the patient's teacher has to carry her into school crying. Her mother recently returned to work full-lime and says that she is quite angry that her daughter is behaving in such a defiant way. Her father recalls that he behaved the same way when he was her age. Which of the following is the most likely explanation for this patient's behavior?
Correct Answer
D. Separation anxiety disorder
Explanation
The most likely explanation for this patient's behavior is separation anxiety disorder. This is indicated by the patient's temper tantrums when her parents leave her, refusal to sleep alone, and calling for her mother when she is in another room. Additionally, her difficulty attending social events and crying when being brought to school are consistent with separation anxiety. The fact that her father recalls behaving the same way at her age suggests a possible genetic predisposition. Conduct disorder and oppositional defiant disorder involve more aggressive and antisocial behaviors. Post-traumatic stress disorder would require a traumatic event as a trigger, which is not mentioned in the scenario. Normal behavior would not explain the chronic and distressing nature of the patient's symptoms.
30.
A 15-year-old boy has intracranial neoplasms, mental retardation, and seizures associated with tuberous sclerosis complex, an autosomal dominant disorder. His 41-year-old mother is healthy but has angiofibromas, which are benign skin lesions characteristic of tuberous sclerosis complex. Which of the following best explains the findings in the boy and his mother?
Correct Answer
E. Variable expressivity
Explanation
Variable expressivity is the best explanation for the findings in the boy and his mother. Variable expressivity refers to the phenomenon where individuals with the same genetic mutation can have different symptoms or severity of symptoms. In this case, both the boy and his mother have tuberous sclerosis complex, but they are manifesting different symptoms. The boy has intracranial neoplasms, mental retardation, and seizures, while the mother only has angiofibromas. This demonstrates the variable expressivity of the disorder, where different individuals can have different manifestations of the same genetic mutation.
31.
A 23-year-old woman is treated with acetazolamide to prevent acute altitude sickness 3 days before going on a mountain-climbing expedition. Acetazolamide acts predominately in which of the following areas of the kidney in this patient?
Correct Answer
E. Proximal tubule
Explanation
Acetazolamide is a carbonic anhydrase inhibitor that is commonly used to prevent altitude sickness. It works by inhibiting the enzyme carbonic anhydrase in the proximal tubule of the kidney. By inhibiting this enzyme, acetazolamide reduces the reabsorption of bicarbonate ions, leading to increased excretion of bicarbonate in the urine. This causes a metabolic acidosis, which stimulates the respiratory center in the brain to increase ventilation, helping to compensate for the decrease in oxygen availability at high altitudes. Therefore, acetazolamide acts predominately in the proximal tubule of the kidney in this patient.
32.
A 40-year-old woman is brought to the emergency department 30 minutes after sustaining severe chest injuries in a motor vehicle collision. Despite appropriate treatment, she dies 1 hour later. She had a 25-year history of a well-controlled seizure disorder. A photograph of a coronal section of the brain obtained at autopsy is shown. Which of the following is the most likely cause of this patient's seizure disorder?
Correct Answer
E. Vascular malformation
Explanation
The most likely cause of this patient's seizure disorder is a vascular malformation. The patient had a well-controlled seizure disorder for 25 years, suggesting a chronic underlying cause. The photograph of the coronal section of the brain obtained at autopsy may show evidence of a vascular malformation, such as an arteriovenous malformation (AVM) or cavernous malformation. These vascular abnormalities can disrupt the normal blood flow in the brain and lead to seizures. Glioblastoma multiforme, herpes simplex encephalitis, mesial temporal sclerosis, and neonatal ischemic stroke are less likely causes in this case.
33.
A 22-year-old nulligravid woman comes to the physician because she has been unable to conceive for 18 months. She has had irregular menses since menarche at the age of 13 years. She is 165 cm (5 ft 5 in) tall and weighs 88 kg (195 lb): BMI is 32 kg/m2. Her temperature is 36.8°C (98.2°F), pulse is 88/min, respirations are 14/min, and blood pressure is 140190 mm Hg. Physical examination shows moderate hirsutism and mild acne over the face and back. Pelvic examination shows no abnormalities of the exterior genitalia; a bimanual examination is limited by the patient's obesity. Which of the following is the most likely cause of this patient's infertility?
Correct Answer
D. Polycystic ovarian syndrome
Explanation
The patient's history of irregular menses, hirsutism, acne, and obesity are consistent with polycystic ovarian syndrome (PCOS). PCOS is a common cause of infertility in women due to hormonal imbalances that affect ovulation. The patient's physical examination findings, including the absence of abnormalities in the exterior genitalia and limited bimanual examination due to obesity, further support the diagnosis of PCOS. Hypothyroidism, Klinefelter syndrome, pituitary adenoma, and primary ovarian failure are less likely causes of infertility in this patient.
34.
A 72-year-old woman is admitted to the intensive care unit after undergoing immediate operative repair of a ruptured colonic diverticulum. During the next 2 weeks, she develops recurrent fevers. After a blood culture grows yeast, micafungin therapy is initiated. This drug most likely targets which of the following cellular structures?
Correct Answer
A. Cell wall
Explanation
Micafungin is an antifungal medication that belongs to the echinocandin class. Echinocandins specifically target the cell wall of fungi. They inhibit the synthesis of β-(1,3)-D-glucan, a major component of the fungal cell wall. By disrupting the cell wall, echinocandins weaken the fungal cell and ultimately lead to cell death. Therefore, the most likely cellular structure targeted by micafungin is the cell wall.
35.
A 60 year-old man comes to the physician because of weakness and light-headedness for 3 months. His diet consists of a healthy balance of fruits, vegetables, whole grains, and lean chicken and fish. He has a 10-year history of chronic autoimmune (Hashimoto) thyroiditis treated with thyroxine. Physical examination shows pallor. Serum studies show increased concentrations of methylmalonic acid and total homocysteine. A peripheral blood smear shows megaloblastic anemia. Which of the following is the most likely cause of the findings in this patient?
Correct Answer
B. Failure of intrinsic factor production
Explanation
The patient's symptoms of weakness, light-headedness, pallor, and megaloblastic anemia are consistent with a diagnosis of pernicious anemia, which is caused by a failure of intrinsic factor production. Intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine. Without intrinsic factor, vitamin B12 cannot be absorbed, leading to a deficiency of this vitamin. This deficiency results in the accumulation of methylmalonic acid and homocysteine, which can be detected in serum studies. The other options, such as cystathionine B-synthase deficiency, folic acid deficiency, Helicobacter pylori gastritis, and methylmalonyl-CoA mutase deficiency, are not associated with the clinical presentation described in the patient.
36.
An 18-year-old man comes to the physician 6 hours after he twisted his ankle while playing football. Physical examination shows looseness of the lateral collateral ligament, suggestive of a tear. Lack of which of the following components in the ligament will roost likely limit healing of this injury?
Correct Answer
A. Blood vessels
Explanation
The lack of blood vessels in the ligament will most likely limit healing of this injury. Blood vessels are essential for delivering oxygen and nutrients to the injured tissues, as well as removing waste products and promoting the inflammatory response necessary for healing. Without an adequate blood supply, the injured ligament may not receive the necessary resources for proper healing, leading to delayed or impaired recovery.
37.
37 missing from original
Correct Answer
A. True
Explanation
The given answer states that 37 is missing from the original. This implies that there is a set or sequence of numbers from which 37 is absent. Therefore, the correct answer is "True" because it affirms the absence of 37 from the original set or sequence.
38.
A 62-year-old man is brought to the emergency department because of a 3-hour history of progressive difficulty breathing and mild left shoulder pain. His symptoms began after he ran up several flights of stairs. He has poorly controlled hypertension and mild angina pectoris. He has smoked one-half pack of cigarettes daily for 40 years. He appears uncomfortable and has labored breathing. Diffuse crackles, rhonchi, and scattered wheezing are heard on auscultation of the posterior lung fields. His arterial Po2 is 58 mm Hg. Which of the following is the most likely diagnosis?
Correct Answer
D. Pulmonary edema
Explanation
The patient's symptoms of progressive difficulty breathing and left shoulder pain, along with his history of poorly controlled hypertension and angina pectoris, suggest a cardiac cause for his symptoms. The fact that his symptoms began after exertion further supports this. The presence of crackles, rhonchi, and wheezing on lung auscultation indicates fluid accumulation in the lungs, which is consistent with pulmonary edema. The low arterial Po2 level also suggests impaired oxygenation. Therefore, the most likely diagnosis in this case is pulmonary edema.
39.
A previously healthy 25-year-old man is admitted to the hospital for treatment of viral pneumonia. He is mechanically ventilated because of respiratory failure due to hypoxemia. An open-lung biopsy specimen is obtained and shows a pattern of acute lung injury. The presence of which of the following in the biopsy specimen most clearly suggests diffuse alveolar damage rather than bronchiolitis obliterans-organizing pneumonia in this patient?
Correct Answer
A. Alveolar hyaline membrane
Explanation
The presence of alveolar hyaline membrane in the biopsy specimen suggests diffuse alveolar damage rather than bronchiolitis obliterans-organizing pneumonia. Alveolar hyaline membrane is a hallmark feature of diffuse alveolar damage, which is commonly seen in acute respiratory distress syndrome (ARDS). It is composed of fibrin, cellular debris, and necrotic epithelial cells lining the alveoli. In contrast, bronchiolitis obliterans-organizing pneumonia is characterized by fibroblastic plugs within the small airways and alveolar ducts. The other options listed are not specific to either condition.
40.
A 31-year-old woman is evaluated because of a 1-year history of infertility. Her hysterosalpingogram is shown. The most likely cause of these findings is malformation of which of the following embryonic tissues?
Correct Answer
D. ParamesonepHric (muillerian) ducts
Explanation
The hysterosalpingogram shows a uterine anomaly, suggesting a malformation of the paramesonephric (muillerian) ducts. These ducts are responsible for the development of the female reproductive tract, including the fallopian tubes, uterus, cervix, and upper vagina. Malformations of the paramesonephric ducts can lead to infertility and other reproductive issues. The other options, such as germ cells, gonadal ridges, mesonephric (wolffian) ducts, urogenital folds, and urogenital sinus, are not directly involved in the development of the female reproductive tract.
41.
A 51-year-old man comes to the physician because of a 2-week history of cough productive of blood. He also has had a 3-kg (6.6-1b) weight loss during the past month. He has smoked 2 packs of cigarettes daily for 32 years. He has hypertension treated with metoprolol. Physical examination shows clubbing of the fingernails. Wheezes are heard over the right upper lobe anteriorly; there are no crackles. Laboratory studies show:
SERUM
Na+ 125 mEq/L
K+ 3.9 mEq/L
CI- 55 mEq/L
HCO3- 25 mEq/L
Urea nitrogen 8 mg/dL
Creatinine 0.4 mg/dL
Osmolality 262 mOsmolikg
Urine osmolality 564 mOsmol/kg
A CT scan of the chest shows a 2.4 x 1.2-cm, spiculated noncalcified mass in the right upper lobe eroding into the right bronchus. This patients laboratory findings are most likely caused by an excess of which of the following hormones?
Correct Answer
A. ADH (vasopressin)
Explanation
The patient's laboratory findings, specifically the low serum sodium level (hyponatremia) and high urine osmolality, suggest the presence of syndrome of inappropriate antidiuretic hormone secretion (SIADH). SIADH is commonly associated with small cell lung carcinoma, which is indicated by the CT scan findings of a mass in the right upper lobe eroding into the right bronchus. ADH (vasopressin) is responsible for the reabsorption of water in the renal tubules, leading to concentrated urine and dilutional hyponatremia. Therefore, an excess of ADH is the most likely cause of the patient's laboratory findings.
42.
A 3-year-old boy is brought to the emergency department because of multiple ecchymoses, bleeding into the joints, and bloody diarrhea 48 hours after ingesting an unknown quantity of warfarin that he took From his grandmother's purse. Prothrombin time is 80 sec (INR=20). Which of the following is the most appropriate initial therapy?
Correct Answer
C. Fresh frozen plasma
Explanation
Fresh frozen plasma is the most appropriate initial therapy in this case because the 3-year-old boy has ingested warfarin, which is a vitamin K antagonist that inhibits the synthesis of factors II, VII, IX, and X. This leads to an increase in prothrombin time (PT) and international normalized ratio (INR). Fresh frozen plasma contains all the coagulation factors, including factors II, VII, IX, and X, and can rapidly correct the coagulopathy caused by warfarin. Factor IX concentrate is used for the treatment of hemophilia B, fibrinogen concentrate is used for the treatment of hypofibrinogenemia, platelet concentrates are used for thrombocytopenia, and vitamin B12 is not indicated in this case.
43.
A 38-year-old woman at 32 weeks' gestation is brought to the physician because of a 2-day history of fever, nausea, vomiting, and muscle aches. She appears acutely ill. Her temperature is 39C (102.2F). pulse is 120/min, and respirations are 20/min. A photomicrograph of a Gram stain of an organism recovered from a blood culture is shown. Which of the following is the most likely causal organism?
Correct Answer
C. Listeria monocytogenes
Explanation
Listeria monocytogenes is a gram-positive rod-shaped bacterium that can cause severe infections, especially in pregnant women. The patient in the scenario is a pregnant woman presenting with fever, nausea, vomiting, and muscle aches, which are consistent with a Listeria infection. Listeria can cause flu-like symptoms and can be transmitted through contaminated food, such as unpasteurized dairy products or deli meats. Given the patient's symptoms and the fact that Listeria can cause serious complications in pregnancy, it is the most likely causal organism in this case.
44.
A 76-year-old woman is brought to the emergency department because of a 3-hour history of severe headache, slurred speech, and confusion. She has a 2-year history of atrial fibrillation. She has difficulty understanding and answering questions, but she is cooperative. Ophthalmologic examination shows hemianopia and a tendency to gaze to the right. The pupils are normal sized and reactive to light. Neurologic examination shows left-sided numbness and paralysis that are more severe in the face and upper extremity than in the lower extremity. Which of the following arteries is most likely involved in this patient’s condition?
Correct Answer
C. Middle cerebral
Explanation
The patient's symptoms, including severe headache, slurred speech, confusion, hemianopia, and gaze preference to the right, are consistent with a stroke. The presence of left-sided numbness and paralysis, more severe in the face and upper extremity, suggests involvement of the contralateral motor cortex. The middle cerebral artery supplies blood to the lateral aspect of the cerebral hemisphere, including the motor cortex, and is the most likely artery involved in this patient's condition.
45.
An 82-year-old woman is admitted to the hospital for treatment of a small right pleural effusion. Physical examination shows dullness to percussion at the level of the 7th rib and below on the right. A thoracentesis is done. The patient is sitting up, supported by leaning against a bedside table. After preparing the skin and delivering a local anesthetic, into which of the following locations on the right is it most appropriate to insert the catheter?
Correct Answer
D. Above the 9th rib in the midscapular line
Explanation
The correct answer is above the 9th rib in the midscapular line. This is the most appropriate location to insert the catheter because it is above the area of dullness to percussion, indicating the location of the pleural effusion. Inserting the catheter above the 9th rib ensures that it will be positioned correctly to drain the effusion.
46.
A 23-year-old woman comes to the physician because of a 1-day history of chills, nausea, and vomiting. She also has a 4-day history of flank pain, urinary frequency and urgency, and pain with urination. Her temperature is 38.9C (102°F), pulse is 125/min, and blood pressure is 96/60 mm Hg. Physical examination shows right costovertebral angle tenderness. Urinalysis shows 25 WBC/hpf. A urine sample grows pink colonies on lactose-MacConkey agar. produces a characteristic green sheen on eosin-methylene blue agar, and is indole positive. The production of which of the following by the bacterium aids in the virulence of the causal organism in this patent?
Correct Answer
A. Adhesins
Explanation
The bacterium in this patient is likely Escherichia coli, as indicated by its characteristics on the agar plates and indole positivity. Adhesins are molecules on the surface of bacteria that enable them to adhere to host cells or tissues. In this case, the production of adhesins by the bacterium aids in its ability to attach to and infect the urinary tract, leading to symptoms such as urinary frequency, urgency, and pain with urination. This adherence is an important step in the pathogenesis of urinary tract infections caused by E. coli.
47.
A 76-year-old man is admitted to the hospital because of a 2-week history of a persistent urinary tract infection. He is 165 cm (5 ft 5 in) and weighs 55 kg (121 lb); BMI is 20 kg/m2. The physician plans to initiate treatment. A component of the initial treatment includes an intravenous bolus dose of an antibiotic to attain an initial peak serum concentration of 8 mg/L. The volume of distribution of the antibiotic is 0.35 L/kg. Laboratory studies show a 24hour urine creatinine clearance within the reference range. Which of the following is the most appropriate loading dose of this drug for this patient (in mg)?
Correct Answer
D. 150
Explanation
The loading dose of a drug is calculated based on the volume of distribution and the desired peak serum concentration. In this case, the volume of distribution is given as 0.35 L/kg and the desired peak serum concentration is 8 mg/L. The patient weighs 55 kg, so the volume of distribution would be 0.35 L/kg * 55 kg = 19.25 L. To achieve a peak serum concentration of 8 mg/L, the loading dose would be 8 mg/L * 19.25 L = 154 mg. Since the question asks for the most appropriate loading dose, the closest option to 154 mg is 150 mg.
48.
A 55-year-old man with hepatic encephalopathy is brought to the physician because of confusion and increased lethargy during the past 24 hours. He has a history of cirrhosis of the liver caused by hepatitis C. He is easily arousable despite the lethargy. His temperature is 37C (98.6F), Physical examination shows scleral icterus, asterixis, a protuberant abdomen, and ascites. Test of the stool for occult blood is negative. Administration of which of the following drugs is most likely to improve this patients mental status?
Correct Answer
C. Lactulose
Explanation
Lactulose is the most likely drug to improve this patient's mental status because he has hepatic encephalopathy, which is a complication of cirrhosis. Lactulose works by decreasing the production and absorption of ammonia in the gut, which is thought to be the main cause of hepatic encephalopathy. By reducing ammonia levels, lactulose can improve the patient's mental status and alleviate symptoms such as confusion and lethargy. The other drugs listed are not indicated for the treatment of hepatic encephalopathy.
49.
49) Missing from original
Correct Answer
A. True
50.
A 22-year-old woman is admitted to the hospital because of a 10-day history of polydipsia and polyuria. She says that the urge to urinate often awakens her at night. She has been taking lithium carbonate for 2 years for bipolar disorder her dosage was increased 6 months ago because of recurrent severe manic episodes. Her vital signs are within normal limits. Physical examination shows no abnormalities. Over the next 24hrs, urine excretion totals 6.5 L. Laboratory studies at this time show a serum sodium concentration of 148 mEq/L, serum osmolality of 315 mOsmol/kg, and urine osmolality of 75 mOsmol/kg. After administration of desmopressin, urine output and osmolality do not change. Which of the following findings in the nephron best describes the tubular osmolality, compared with serum, in this patient?
Proximal Tubule Juxtaglomerular Apparatus Medullary Collecting Duct
A) Hypertonic----------hypertonic----------hypertonic
B) Hypertonic----------hypertonic----------hypotonic
C) Hypertonic----------hypotonic-----------hypotonic
D) Isotonic --------------isotonic--------------isotonic
E) Isotonic --------------hypotonic-----------hypertonic
F) Isotonic --------------hypotonic-----------hypotonic
G) Hypotonic-----------hypertonic-----------hypertonic
H) Hypotonic----------hypotonic------------hypertonic
I) Hypotonic----------hypotonic------------hypotonic
Correct Answer
F. F
Explanation
In this patient, the urine osmolality is significantly lower than the serum osmolality, indicating that the tubular fluid is more dilute compared to the serum. This suggests that water is being reabsorbed in the tubules, leading to a hypotonic tubular fluid. The only option that matches this finding is option F, which states that the tubular osmolality is hypotonic compared to the serum in all three segments of the nephron (proximal tubule, juxtaglomerular apparatus, and medullary collecting duct).