🇨🇦 MCCQE1,2 | #Case_210
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An 83-year-old male has a long history of COPD. His resting oxygen saturation is 86% on room air. Treatment includes
oral bronchodilators, inhaled corticosteroids, inhaled beta-agonists, inhaled anticholinergics, and home oxygen. Which one of his treatments has been shown to prolong survival in cases such as this?

a) Oral bronchodilators
b) Inhaled corticosteroids
c) Inhaled beta-agonists
d) Inhaled anticholinergics
e) Home oxygen

🇨🇦 MCCQE1,2 | #Case_210 | #answer
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✅ E

🔎 Explanation

Treatment of hypoxemia is critical in the management of COPD and trials have shown a reduction in mortality with the use of oxygen for 15 or more hours daily.

⚠ Inhaled beta-adrenergic agonists and anticholinergic agents, either alone or in combination, provide symptomatic relief but do not prolong survival.

⚠ Theophylline can be used for symptoms inadequately relieved by bronchodilators.

⚠ Inhaled corticosteroids do not appear to alter the rate of decline in lung function in COPD. However, some evidence shows that these agents alleviate symptoms and reduce disease exacerbation. Pulmonary rehabilitation improves quality of life and reduces hospitalizations.

🇨🇦 MCCQE1,2 | #Case_211
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A 68-year-old man with a history of diabetes, hypertension and atrial fibrillation is admitted to the ER for severe abdominal pain. He has vomited twice in the last hour and has had one bloody stool. The patient is complaining of severe pain but your exam reveals a soft abdomen. His vitals are: HR:140 bpm, BP:85/60 mmHg, RR:19 rpm, T:38.9°C. An abdominal x-ray shows pneumatosis intestinalis (air in the bowel wall). Which of the following would be your next best step?

a) Colonoscopy
b) Complete blood count stat
c) Barium enema
d) Watchful waiting
e) Exploratory laparotomy

🇨🇦 MCCQE1,2 | #Case_211 | #answer
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✅ E

🔎 Explanation

With this patient’s history of pain out of proportion to physical findings, vomiting, bloody stool, unstable vitals and pneumatosis intestinalis on x-ray you should be highly suspicious of acute mesenteric ischemia (AMI). It is very likely that the source of the AMI was an arterial embolus most likely as a result of the patient’s atrial fibrillation (>75% of emboli originate in the heart). AMI risk factors include: atrial fibrillation, recent MI, valvular heart disease and recent vascular catheterization. The most common anatomic sites for ischemia are “Sudeck’s point” at the sigmoid flexure and “Griffith’s point” at the transverse-descending colon flexure. Immediate surgery is the gold standard for diagnosis but CT, mesenteric angiography, abdominal radiography and ECG are useful for diagnosis.

⚠ Colonoscopy, is not useful for suspected cases of AMI.

⚠ No laboratory test sufficiently rules in or rules out the diagnosis of mesenteric ischemia. Laboratory findings in mesenteric ischemia are nonspecific and generally unreliable.

⚠ Barium enema, is contraindicated. Considering a mortality rate of >50% in cases of AMI,

⚠ Watchful waiting would serve only to render a negligence lawsuit against you.

🔖 Key point:

If AMI is suspected surgical exploration should not be delayed

🇨🇦 MCCQE1,2 | #Case_212
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A 45-year-old white male is admitted to the intensive-care unit after being pinned in a car wreck for 2 hours. He has sustained several broken bones and crush injuries to both thighs. On admission his urine is clear but the next morning it is burgundy colored. Some fresh urine is drawn from his Foley catheter and sent for analysis, with the following results:
Specific gravity. ......... 1.020
pH............................... 6.0
Protein........................ 30 mg/dL (N 1-14)
Glucose. .................... negative
Hemoglobin................ 4+
Urobilinogen. ............. 0.1 Ehrlich Units (N 0.1-1.0)
Bile............................. negative
RBCs......................... 1-2/hpf
WBCs. ...................... 0-2/hpf
Occasional hyaline casts

You immediately order a CBC which shows his hematocrit to have dropped 4 percentage points overnight. Visual inspection of the serum shows it is clear. The color of his urine is most likely due to:

a) Myoglobinuria
b) Hematuria from trauma to the urinary tract
c) A transfusion reaction with hemolysis of RBCs and free hemoglobin into the urine
d) Hemoglobinuria resulting from reabsorption of hemoglobin from hematomas
e) Acute porphyria provoked by trauma

🇨🇦 MCCQE1,2 | #Case_212 | #answer
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✅ A

🔎 Explanation

A positive dipstick for hemoglobin without any RBCs noted in the urine sediment indicates either free hemoglobin or myoglobin in the urine. Since the specimen in this case was a fresh sample, significant RBC hemolysis within the urine would not be expected.
Myoglobin is released when skeletal muscle is destroyed by trauma, infarction, or intrinsic muscle disease.

⚠ If the hematuria were due to trauma there would be many RBCs visible on microscopic examination of the urine.

⚠ If a transfusion reaction occurs, haptoglobin binds enough free hemoglobin in the serum to give it a pink coloration. Only when haptoglobin is saturated will the free hemoglobin be excreted in the urine.

⚠ Free hemoglobin resorption from hematomas does not occur.

⚠ Porphyria may cause urine to be burgundy colored, but it is not associated with a positive urine test for hemoglobin

🇨🇦 MCCQE1,2 | #Case_213
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You are called to evaluate a term newborn in the delivery room. The pregnancy and delivery were uneventful, but the baby has remained cyanotic despite routine delivery room care. A
hyperoxia test is performed; the results of which are printed below:
FiO2 = 0.21, PaO2 = 30
FiO2 = 1.00, PaO2 = 40

Which statement is the correct interpretation of the test results above?

a) The test results suggest that the baby has a cardiac defect involving restricted pulmonary blood flow or a separate circulation
b) The baby has a normal PaO2 for a newborn
c) The test results suggest that the baby has underlying neurologic disease
d) The test results suggest that the baby has a cardiac defect involving complete mixing without restricted pulmonary blood flow

🇨🇦 MCCQE1,2 | #Case_213 | #answer
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✅ A

🔎 Explanation

The hyperoxia test is used as an early tool to evaluate the cyanotic neonate to determine if the etiology of the cyanosis is cardiac or non-cardiac in origin. A right radial artery (preductal) blood gas is performed with the child inspiring room air and 100% oxygen. The change in PaO2 with the administration of oxygen issued as a guide to determine the etiology of the cyanosis. A PaO2 of less than 150 with the administration of 100% oxygen suggests a cardiac lesion. The cardiac lesions may be further classified based upon the absolute value of the PaO2. A PaO2 of less than 50 on 100% oxygen suggests a cardiac
disorder, in which there is restricted pulmonary blood flow or a separate venous and arterial circulation, whereas a PaO2 between 50 and 150 on 100% oxygen suggests that there is no restriction of pulmonary blood flow in the presence of complete mixing of oxygenated and deoxygenated blood. In this case, the PaO2 on 100% oxygen was less than 50, suggesting restricting pulmonary blood flow or a separate circulation

🇨🇦 MCCQE1,2 | #Case_214
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A 26-year-old female presents with a 1-year history of recurring abdominal pain associated with intermittent diarrhea, 5-7 days per month. Her pain improves with defecation. She denies blood in her stool and weigh loss. Laboratory tests
(including a CBC, chemistry profile, TSH level, and antibodies for celiac disease) came back normal. Which one of the following would be most appropriate at this point?

a) Colonoscopy
b) An upper GI series with small-bowel follow-through
c) Abdominal CT with contrast
d) A gluten-free diet
e) Loperamide

🇨🇦 MCCQE1,2 | #Case_214 | #answer
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✅ E

🔎 Explanation

This patient has classic symptoms of irritable bowel syndrome (IBS) and meets the Rome criteria by having 3 days per month of abdominal pain for the past 3 months, a change in the frequency of stool, and improvement with defecation. According to current clinical guidelines IBS can be diagnosed by history, physical examination, and routine laboratory

🇨🇦 MCCQE1,2 | #Case_215
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A 68-year-old woman comes to the office for flexible sigmoidoscopy as part of a yearly screening. A 3 cm polyp is found in the sigmoid colon and is removed. She returns now to the office, 6 hours later, complaining of left lower quadrant pain, fever, nausea and vomiting. Vital signs are: temperature 38.1°C (100.6°F), pulse 110/min, respirations 26/min and blood pressure 120/60 mm Hg. Abdominal examination discloses bowel sounds, tenderness and guarding in the left lower
quadrant. Rectal examination shows no stool and only tenderness superiorly The most appropriate next step is to:

a) Obtain an angiogram to rule out intestinal ischemia
b) Obtain immediate consultation with a surgeon
c) Pass a soft rubber rectal tube under fluoroscopy
d) Repeat the flexible sigmoidoscopy in order to evaluate the operative site
e) Start hydrocortisone, intravenously, to decrease any inflammatory response

🇨🇦 MCCQE1,2 | #Case_215 | #answer
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✅ B

🔎 Explanation

The physical findings described clearly suggest a probable colon perforation at the site of the polypectomy, and therefore surgical consultation is warranted. There is no reason to suspect ischemia, and any further instrumentation of the colon is contraindicated. The patient should be prepped for probable surgery with antibiotics and not hydrocortisone since she is already at risk for peritonitis

🇨🇦 MCCQE1,2 | #Case_216
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A 47-year-old female presents to your office with a complaint of hair loss. On examination she has a localized 2-cm round area of complete hair loss on the top of her scalp. Further studies do not reveal an underlying metabolic or infectious disorder. Which one of the following is the most appropriate initial treatment?

a) Topical minoxidil
b) Topical immunotherapy
c) Intralesional triamcinolone
d) Oral finasteride
e) Oral spironolactone

🇨🇦 MCCQE1,2 | #Case_216 | #answer
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✅ C

🔎 Explanation

These findings are consistent with alopecia areata, which is thought to be caused by a localized autoimmune reaction to hair follicles. It occasionally spreads to involve the entire scalp (alopecia totalis) or the entire body (alopecia universalis). Spontaneous recovery usually occurs within 6-12 months, although areas of regrowth may be pigmented differently. Recovery is less likely if the condition persists for longer than a year, worsens, or begins before puberty. The initial treatment of choice for patients older than 10 years of age, in cases where alopecia areata affects less than 50% of the scalp, is intralesional corticosteroid injections.

⚠ Minoxidil is an alternative for children younger than 10 years of age or for patients in whom alopecia areata affects more than 50% of the scalp.

⚠ While topical immunotherapy is the most effective treatment for chronic severe alopecia areata, it has the potential for severe side effects and should not be used as a first-line agent.

⚠ Finasteride inhibits 5-reductase type 2, resulting in a decrease in dihydrotestosterone levels, and is used in the treatment of androgenic alopecia (male-pattern baldness). Similarly, spironolactone is sometimes used for androgenic alopecia because it is an aldosterone antagonist with antiandrogenic effects.

🇨🇦 MCCQE1,2 | #Case_217
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A 78-year-old white male is scheduled to undergo CT with contrast. His current diagnoses include type 2 diabetes mellitus, heart failure, anemia of chronic disease, and renal insufficiency. Evidence supports the use of which one of the following to reduce the risk of contrast-induced nephropathy in this patient?

a) Intravenous furosemide
b) Ascorbic acid
c) Calcium antagonists
d) Isotonic bicarbonate infusion
e) High osmolar contrast media

🇨🇦 MCCQE1,2 | #Case_217 | #answer
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✅ D

🔎 Explanation

Prospective randomized trials examining the risk for contrast-induced nephropathy have identified significant differences between contrast agents due to their physiochemical properties. Low-osmolar or iso-osmolar contrast media should be used to prevent contrast-induced nephropathy in at-risk patients. The volume of contrast medium should be as low as possible. Evidence also supports hydration before the procedure, preferably with isotonic saline or isotonic sodium bicarbonate solution. There is limited evidence that any pharmacologic intervention will prevent contrast-induced nephropathy

🇨🇦 MCCQE1,2 | #Case_218
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A 65-year-old male presents with a 1-month history of problems passing urine. He says that his bladder will feel full when he needs to urinate, but the urine stream is weak and his bladder does not feel as if it has emptied completely. The symptoms have become increasingly severe over the past week. Other symptoms include upper respiratory congestion for 3 days which he has treated with an over-the-counter decongestant with some relief, constipation with no passage of stool in the past 9 days, and increasing low back pain incompletely relieved with ibuprofen, with associated weakness in both legs.Examination shows a healthy-appearing male who is moderately overweight. He is afebrile and vital signs are normal. There is no abdominal tenderness and no masses are detected. A rectal examination reveals a large amount of hard stool in the rectum; a markedly enlarged (4+), boggy, tender prostate gland; laxity of the anal sphincter; and numbness in the perianal area. Urinalysis shows trace protein and 10-20 WBCs/hpf. Ultrasonography shows a post-void residual volume of 250 mL (normal for age < 100). Which one of the following must be done urgently in this patient?

a) Foley catheterization
b) Hospitalization for intravenous antibiotics
c) Digital disimpaction of the rectum, and Fleet enemas until clear
d) MRI of the lumbosacral spine

🇨🇦 MCCQE1,2 | #Case_218 | #answer
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✅ D

🔎 Explanation

The differential diagnosis of urinary retention in the elderly is broad. While most causes are benign and readily treated, the physician must be vigilant in looking for conditions that require urgent intervention. This patient presents with many possible causes of urinary retention, with the most common being benign prostatic hyperplasia. Acute prostatitis, especially in a male with an enlarged prostate, is another relatively common reason for obstructive symptoms. This patient’s physical examination and abnormal urinalysis support this diagnosis, but his normal vital signs and lack of fever suggest he can be treated with an oral fluroquinolone and does not require hospital admission for intravenous therapy. Medications such as oral decongestants can contribute to urinary retention in men with enlarged prostate glands, and should be used with caution and discontinued if obstructive symptoms occur. Obstipation (severe constipation caused by intestinal obstruction) with stool impaction is another relatively common reason for urinary retention in the elderly and can be treated with manual disimpaction and enemas. In this patient, the presence of increasing low back pain and leg weakness, and the findings of anal sphincter laxity and numbness in the perianal area on examination, suggest the presence of a serious neurologic etiology such as cauda equina syndrome. Urgent diagnosis and treatment are necessary to reduce morbidity, and MRI should be performed immediately. The presence of a mildly elevated post-void residual is not an indication for urgent decompression with a Foley catheter

🇨🇦 MCCQE1,2 | #Case_219
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A 55-year-old male with coronary artery disease undergoes coronary artery bypass grafting (CABG). The operation is uneventful, but 2 hours after the surgery he suddenly spikes a fever to 40.0˚C (104.0˚F). The patient’s pulse rate is 110 beats/min and his blood pressure is 140/85 mm Hg. He remains on the ventilator and does not awaken during the episode. The physical examination is otherwise unremarkable except for his surgical incisions. He has no history of recent infection prior to the surgery and his WBC count is not elevated. Apart from hypertension and coronary artery disease, his past medical and surgical histories are negative. The most likely explanation for this patient’s fever is:

a) Transient bacteremia
b) Aspiration pneumonia
c) Urosepsis
d) Malignant hyperthermia
e) Post-pericardiotomy syndrome

🇨🇦 MCCQE1,2 | #Case_219 | #answer
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✅ D

🔎 Explanation

Malignant hyperthermia is an inherited myopathy in which abnormalities of skeletal-muscle sarcoplasmic reticulum cause an increase in intracellular calcium levels, resulting in sustained muscular contraction and a hypermetabolic state. This condition is most often triggered by inhalational anesthetics (e.g., halothane) or by succinylcholine, used for muscle paralysis. It results in a sudden rise in temperature, tachycardia, increased muscle tone, and eventual muscle rigidity. If unrecognized and untreated, there is a downward spiral with rhabdomyolysis, acidosis, renal failure, cardiovascular instability, and death. It usually presents in the operating room or the recovery room, and prompt recognition and treatment with dantrolene, along with cooling the patient, reduces morbidity and mortality risks. While urosepsis, pneumonia, and bacteremia are possible complications of the surgery, none of these is the most likely cause of fever in this scenario. Post-pericardiotomy syndrome (Dressler’s syndrome) occurs at least 2 weeks postoperatively and is manifested by low-grade fever and chest pain.

🇨🇦 MCCQE1,2 | #Case_220
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A 27-year-old female who recently delivered a baby girl at your department through Ceasarian section suddenly seems confused. She also presents with excessive sweating, and hand twitching. Her past medical history is significant for asthma managed with albuterol as needed. She is allergic to latex. She takes no other medications but regularly uses 2 supplements: St John’s Wort and 5-HTP. Prior to the C-section she received an epidural anesthesia with bupivacaine. Her post-surgery pain was managed with meperidine. On physical examination her vital signs are T: 39.1°C, BP: 140/90 mmHg; HR: 110/min; respirations 17/min. Knee and ankle reflexes are overactive. Clonus is noted. Which of the following is the best explanation for her current condition?

a) She has neuroleptic malignant syndrome
b) It is caused by the pre-C-section anesthesia and genetic predisposition
c) It is caused by cytokine release after child birth via C-section
d) Interaction between meperidine and supplements occured
e) She suffers from anxiety and panic attack because of her surgery