Question 1

The fundamental benefit of applying positive end-expiratory pressure (PEEP) to an 80-year-old patient with a large closing volume would be that PEEP: A) Increases the area available for gas exchange by opening closed alveoli B) Increases compliance, making it easier to breathe C) Promotes an increase in pulmonary blood flow D) Significantly increases the PaO₂ when the patient is breathing air E) Stimulates breathing by tonically activating pulmonary stretch receptors

Accepted Answer

PEEP helps to keep alveoli open at the end of expiration, increasing the area available for gas exchange by preventing alveolar collapse. This is particularly beneficial in patients with a large closing volume, such as the elderly, where alveoli tend to collapse more easily.

Question 2

A 44-year-old woman complains of increased 'hairiness' that has developed over her face and body over the past 2 years. Physical exam reveals increased hair growth over the upper lip, chin, chest, and abdomen, but no truncal obesity or purple striae. Laboratory values of which hormones would provide the most pertinent diagnostic information? A) Cortisol and thyroxine (T₄) B) Estrogen and progesterone C) Follicle stimulating hormone (FSH) and luteinizing hormone (LH) D) 17-alpha-hydroxyprogesterone E) Testosterone and dehydroepiandrosterone (DHEA) sulphate

Accepted Answer

Testosterone and dehydroepiandrosterone (DHEA) sulphate levels are most relevant for diagnosing hirsutism, as they are androgens that can cause increased hair growth when present in elevated levels.

Question 3

An 8-year-old girl developed 'rosy cheeks' while playing outside on a chilly day. What is thought to be the cause of this vasodilation? A) Paralysis of vascular smooth muscle B) A decreased thermoregulatory 'set point' C) Increased prostaglandin E₂ (PGE₂) production D) Increased parasympathetic activity E) Secretion of progesterone

Accepted Answer

Paralysis of vascular smooth muscle is thought to be the cause of this vasodilation. When exposed to cold, the initial vasoconstriction response may be followed by a paradoxical vasodilation, often attributed to the temporary paralysis or decreased responsiveness of the vascular smooth muscle to sympathetic stimulation, leading to increased blood flow and the 'rosy cheeks' appearance.

Question 4

A 15-year-old girl is brought to her doctor because of increased irritability, restlessness, weight loss and learning problems over the past 2 months. Physical examination reveals no abnormalities. Laboratory studies reveal increased triiodothyronine (T₃) and thyroxine (T₄) levels. Which of the following is the most likely diagnosis? A) Hypoglycemia B) Diabetes mellitus C) Hyperthyroidism D) Pituitary adenoma E) Thyroid cancer

Accepted Answer

The symptoms and laboratory findings of increased triiodothyronine (T3) and thyroxine (T4) levels are indicative of hyperthyroidism, which explains the irritability, restlessness, weight loss, and learning problems.

Question 5

A 60-year-old woman complains of persistent breathing difficulties. Her laboratory studies show: pH 7.36; [H⁺] 44 nmol/L; PaCO₂ 55 mmHg; [HCO₃^-] 30 mmol/L. Which of the following is the most likely diagnosis? A) Combined metabolic acidosis and respiratory acidosis B) Primary respiratory acidosis, secondary metabolic alkalosis, full pH compensation C) Primary respiratory acidosis, secondary metabolic alkalosis, partial pH compensation D) Pure metabolic acidosis without pH compensation E) Pure respiratory acidosis

Accepted Answer

The answer of A 60-year-old woman complains of persistent breathing...

Question 6

A 23-year-old girl complains of a 3-month history of malaise and generalized muscle cramps. Laboratory results reveal: serum sodium 144 mmol/L; serum potassium 2.0 mmol/L; serum bicarbonate 40 mmol/L; arterial pH 7.5. Which of the following is the most likely cause of this patient's hypokalemic alkalemia?
A) Hyperaldosteronism
B) Hyperventilation
C) Persistent diarrhea
D) Renal failure
E) Diabetes mellitus

Accepted Answer

Hyperaldosteronism is the most likely cause of hypokalemic alkalemia in this patient, as it leads to increased potassium excretion and bicarbonate reabsorption, resulting in low potassium levels and a high blood pH.

Question 7

While on a rotation in India, you encounter a 10-year-old patient who is suffering cholera and is severely dehydrated. You are asked to prepare an oral rehydration solution. What, in addition to water, would the most important components of the solution be?
A) Bicarbonate and potassium
B) Chloride and potassium
C) Lactate and potassium
D) Sodium and bicarbonate
E) Sodium and glucose

Accepted Answer

Sodium and glucose are the most important components of an oral rehydration solution for treating dehydration caused by cholera. Sodium helps with water absorption in the intestines, and glucose enhances sodium (and thus water) absorption through the sodium-glucose co-transport mechanism.

Question 8

A 47-year-old male arrives in the emergency department with acute anterior chest pain, which radiates to the left arm and back and has lasted for 1 h. He is 80 in tall and weighs 190 lbs. His blood pressure is 115/70 mmHg, pulse 116/min, and respiratory rate 20/min. The lungs are clear and an electrocardiogram (ECG) shows no abnormalities. Which of the following is the most likely diagnosis?
A) Angina pectoris
B) Myocardial infarction (MI)
C) Aortic dissection
D) Cervical disc disease
E) Pericardial tamponade

Accepted Answer

The symptoms described, including acute anterior chest pain radiating to the back and left arm, in the absence of ECG abnormalities, are highly suggestive of aortic dissection. This condition often presents with severe chest or back pain and can mimic other cardiac conditions, but the radiation pattern and normal ECG help differentiate it.

Question 9

A 67-year-old man suffering from metastatic prostate cancer arrives at your emergency department 2 h after the sudden onset of anterior chest pain and shortness of breath. The pain is enhanced by deep breathing movements. He is hypotensive and exhibits a rapid pulse and respiration rate. His blood pressure is 100/56 mmHg, pulse 136/min and respiration rate 28/min. Although the lungs are clear, an electrocardiogram (ECG) shows a right axis deviation not observed before. Which of the following is the most likely diagnosis?
A) Pneumonia
B) Pulmonary embolism
C) Pneumothorax
D) Lung cancer
E) Esophageal spasm

Accepted Answer

The patient's symptoms of sudden onset anterior chest pain, shortness of breath, hypotension, rapid pulse, and respiration rate, along with the ECG showing a new right axis deviation, are highly suggestive of a pulmonary embolism.

Question 10

A 6-week-old boy is brought to his pediatrician by his mother because of progressively worsening projectile vomiting over the past 2 weeks. Physical examination reveals a wasted, dehydrated infant who is avidly sucking on a nipple. Which of the following laboratory values is most consistent with this child's problem ? 
A)
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C)
D)
E)

Accepted Answer

The answer of A 6-week-old boy is brought to his...

Question 11

A 58-year-old man complains of tinnitus that is loudest in his right ear and a decreased sense of taste in the anterior portion of his tongue. His symptoms have become progressively worse during the past 6 months. His physical examination is within normal limits. Which of the following is the most likely diagnosis?
A) Acoustic neuroma
B) Lacunar stroke in the internal capsule
C) Lesion in the caudal medulla
D) Lesion in the mesencephalic tegmentum
E) Lesion in the tectum

Accepted Answer

Acoustic neuroma, also known as vestibular schwannoma, is a benign tumor that arises from the Schwann cells covering the vestibulocochlear nerve (cranial nerve VIII). It can cause symptoms such as tinnitus and hearing loss, primarily affecting one ear. The decreased sense of taste in the anterior portion of the tongue could be related to involvement of the nearby facial nerve (cranial nerve VII), which is responsible for taste sensation in the anterior two-thirds of the tongue. The progressive nature of the symptoms and the specific combination of tinnitus and taste disturbance make acoustic neuroma the most likely diagnosis.

Question 12

A 69-year-old man is diagnosed with benign prostatic hypertrophy (BPH). Which of the following hormones is primarily responsible for prostatic enlargement in BPH?
A) Testosterone
B) Androstenedione
C) Dihydrotestosterone (DHT)
D) Estrone
E) Estradiol

Accepted Answer

Dihydrotestosterone (DHT) is the primary hormone responsible for prostatic enlargement in benign prostatic hypertrophy (BPH). Testosterone is converted to DHT by the enzyme 5-alpha-reductase in prostate cells, and DHT has a more potent effect on prostate growth than testosterone.

Question 13

An 18-year-old patient with trisomy 21 has an unrepaired complete atrioventricular (AV) canal defect and pulmonary hypertension. She is complaining of headache and dizziness. Which of the following tests would be most likely to reveal the etiology of these complaints?
A) Electrocardiography (ECG)
B) Electroencephalography (EEG)
C) Hematocrit
D) Sinus radiography
E) Urinalysis

Accepted Answer

Patients with unrepaired complete atrioventricular (AV) canal defect and pulmonary hypertension are at risk for developing secondary erythrocytosis due to chronic hypoxemia. This condition can lead to increased blood viscosity, which in turn can cause symptoms such as headache and dizziness. Hematocrit measurement is the most direct way to assess for erythrocytosis, making it the most likely test to reveal the etiology of these complaints in this patient.

Question 14

Upon awakening one morning, a 62-year-old man, is unable to use his right hand. In addition, he recently experienced conjugate deviation of the eyes to the left and paralysis of voluntary gaze to the right; 5 days later, however, his eye movements returned to normal. This patient probably has had a stroke involving the:
A) Left frontal cortex
B) Left mesencephalic tegmentum
C) Left occipital cortex
D) Right lateral geniculate nucleus
E) Right occipital cortex

Accepted Answer

The symptoms described, including inability to use the right hand, conjugate deviation of the eyes to the left, and paralysis of voluntary gaze to the right, are indicative of a stroke involving the left frontal cortex. This area is responsible for motor functions (explaining the right hand paralysis due to the contralateral control of the body by the brain) and voluntary eye movements, specifically through the frontal eye fields which control gaze direction. The temporary nature of the eye movement symptoms suggests a transient ischemic attack (TIA) or minor stroke with partial recovery.

Question 15

A 56-year-old female complains of generalized weakness and a 20 lb weight loss over the past 6 months. Blood pressure is 136/80 mmHg and pulse is 88/min. Laboratory values reveal a hematocrit of 31% (normal 40-45%), hemoglobin level of 10 g/dL (normal 14 g/dL), and a blood smear shows hypochromic microcytic cells. A stool test for occult blood is positive. Which of the following would be the most likely cause of the findings?
A) Acute blood loss
B) Folic acid deficiency
C) Hemochromatosis
D) Iron deficiency
E) ($\beta$)-Thalassemia trait

Accepted Answer

The patient's symptoms of generalized weakness, weight loss, and the laboratory findings of hypochromic microcytic cells along with a positive stool test for occult blood suggest iron deficiency anemia, likely secondary to chronic blood loss, possibly from the gastrointestinal tract.

Question 16

A previously healthy 2-year-old girl who developed a sudden onset of persistent coughing is brought to the pediatric clinic. She has no fever and now is coughing up bright red, frothy blood. What is the most likely cause of this child's problem?
A) Arteriovenous malformation of the lung
B) Cystic fibrosis
C) Foreign body in the bronchus
D) Pneumonia
E) Tuberculosis

Accepted Answer

Foreign body aspiration is a common cause of sudden onset coughing and potentially life-threatening respiratory distress in children, especially around the age of 2 years, when they are prone to putting objects in their mouths. The presence of bright red, frothy blood suggests significant irritation or injury within the respiratory tract, which can occur with a foreign body lodged in the bronchus.

Question 17

An 8-year-old girl has headache, vomiting, and hypertension. She appears adequately hydrated. Laboratory values are: serum sodium concentration 110 mEq/L (normal 135-145 mEq/L); blood urea nitrogen 10 mg/dL (normal 7-22 mg/dL); serum creatinine, 0.4 mg/dL (normal 0.3-0.7 mg/dL). The sodium concentration of a random sample of urine is 100 mEq/L (normal 130-260 mEq/24 h). An increase in which of the following hormones is the most likely cause of these findings?
A) Antidiuretic hormone (ADH)
B) Atrial natriuretic peptide (ANP)
C) Estrogen
D) Glucocorticoid
E) Mineralocorticoid

Accepted Answer

The symptoms and laboratory values suggest the patient is suffering from the syndrome of inappropriate antidiuretic hormone secretion (SIADH), where there is an excessive release of antidiuretic hormone (ADH). This leads to water retention, dilutional hyponatremia (low serum sodium), and relatively concentrated urine despite the presence of low serum sodium. The presence of headache, vomiting, and hypertension, along with hyponatremia and the urine sodium concentration, supports this diagnosis.

Question 18

A 60-year-old hypertensive man is diagnosed with stenosis of a major renal artery. To compensate for decreased blood perfusion of the affected kidney, he produces an excess of the compound labeled X in the figure below. Which of the following best characterizes compound X? A) It causes arteriolar vasoconstriction. B) It is produced by juxtaglomerular cells of the kidney. C) It is secreted in response to infusions rich in Na⁺. D) It is under tight control of adrenocorticotropic hormone (ACTH). E) It promotes sodium retention and potassium excretion in the distal tubules of nephrons.

Accepted Answer

The answer of A 60-year-old hypertensive man is diagnosed with...

Question 19

A 14-year-old boy complains of a 3-week history of weight loss, excessive thirst, and urination. Type 1 diabetes mellitus is suspected. Laboratory testing of blood samples will most likely show:
A) Increased erythrocyte sedimentation rate
B) Increased serum creatinine level
C) Presence of anti-pancreatic amyloid antibodies
D) Presence of anti-pancreatic islet cell antibodies
E) Presence of anti-streptolysin O antibodies

Accepted Answer

The presence of anti-pancreatic islet cell antibodies is indicative of an autoimmune attack on the pancreatic beta cells, which is a hallmark of Type 1 diabetes mellitus.

Question 20

A 15-year-old boy complains of vomiting, anorexia, and weight loss. Laboratory studies reveal: serum calcium 13 mg/dL (normal 8.7-10.6 mg/dL); blood urea nitrogen 36 mg/dL (normal 7-22 mg/dL); serum creatinine, 1.8 mg/dL (normal 0.3-0.7 mg/dL). He has been taking several high-potency vitamin supplements daily for the past year as part of a 'body-building' program. An excess of which of the following vitamins is the most likely cause of these findings?
A) Vitamin A
B) Vitamin B
C) Vitamin C
D) Vitamin D
E) Vitamin E

Accepted Answer

The symptoms and laboratory findings are indicative of hypercalcemia, which can be caused by excessive intake of Vitamin D. Vitamin D enhances calcium absorption from the gut, leading to increased serum calcium levels.

Quiz 3: The Nervous System

The fundamental benefit of applying positive end-expiratory pressure (PEEP) to an 80-year-old patient with a large closing volume would be that PEEP:

An 8-year-old girl developed 'rosy cheeks' while playing outside on a chilly day. What is thought to be the cause of this vasodilation?

A 60-year-old woman complains of persistent breathing difficulties. Her laboratory studies show: pH 7.36; [H⁺] 44 nmol/L; PaCO₂ 55 mmHg; [HCO₃^-] 30 mmol/L. Which of the following is the most likely diagnosis?

While on a rotation in India, you encounter a 10-year-old patient who is suffering cholera and is severely dehydrated. You are asked to prepare an oral rehydration solution. What, in addition to water, would the most important components of the solution be?

A 69-year-old man is diagnosed with benign prostatic hypertrophy (BPH) . Which of the following hormones is primarily responsible for prostatic enlargement in BPH?

An 18-year-old patient with trisomy 21 has an unrepaired complete atrioventricular (AV) canal defect and pulmonary hypertension. She is complaining of headache and dizziness. Which of the following tests would be most likely to reveal the etiology of these complaints?

A previously healthy 2-year-old girl who developed a sudden onset of persistent coughing is brought to the pediatric clinic. She has no fever and now is coughing up bright red, frothy blood. What is the most likely cause of this child's problem?

A 60-year-old hypertensive man is diagnosed with stenosis of a major renal artery. To compensate for decreased blood perfusion of the affected kidney, he produces an excess of the compound labeled X in the figure below. Which of the following best characterizes compound X?

A 14-year-old boy complains of a 3-week history of weight loss, excessive thirst, and urination. Type 1 diabetes mellitus is suspected. Laboratory testing of blood samples will most likely show: