🇨🇦 MCCQE1,2 | #Case_167
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A 60 year old woman had an abdominal hysterectomy and salpingo-oophorectomy 3 days ago. She had an indwelling bladder catheter, which was removed in the recovery room. She has been voiding normally since then. She began ambulation on the 1st postoperative day, and has been as active as possible under the circumstances, including faithful adherence to a prescribed program of incentive spirometry. On the evening of the 3rd postoperative day, she spikes a fever, with a temperature to 39.4°C (103°F). Which of the following is the most likely source of the fever?

❤Atelectasis
💛Deep thrombophlebitis
💚Intra-abdominal abscess
💙Urinary tract infection
💜Wound infection

🇨🇦 MCCQE1,2 | #Case_167 | #answer
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✅ D

🔎 Explanation

The timing is our major clue. Fever on postoperative day 3 is usually from the urinary tract. The circumstances are also there: she had instrumentation of her urinary tract during the procedure. Atelectasis is usually seen on day 1, and she is doing everything possible to avoid this complication. Deep thrombophlebitis could show up this early, but is more likely to do so 5-7 days after surgery. Furthermore, the patient had adequate protection during surgery and has been moving around since early on. Intra-abdominal abscess would need at least 7-10 days to develop. This is too early for that

🇨🇦 MCCQE1,2 | #Case_168
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A 40 year old male is brought to the emergency department in a confused state. His past medical history is unremarkable. He is not taking any medications. He is complaining of severe, weakness and lightheadedness that began an hour ago. A STAT glucometer reveals a value of 2.5 mmol/L. The patient improved dramatically upon Dextrose 50% infusion. After careful history and physical exam, you ordered some lab tests that return abnormal for an elevated insulin levels and decreased C-Peptide. Which of the following is the most likely diagnosis?

❤Chronic pancreatitis
💛Factitious disorder
💚Glucagonoma
💙Insulinoma
💜Sulphonylurea overdose

🇨🇦 MCCQE1,2 | #Case_168 | #answer
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✅ B

🔎 Explanation


Our patient has classic symptoms of hypoglycemia (confusion, weakness, lightheadedness…), documented by lab test, then improved dramatically with glucose administration (Whipple’s triad). This patient is likely injecting insulin surreptitiously for a primary gain (factitious disorder or Munchausen syndrome). The exogenous industrial insulin is purified and does not have the C-peptide as a component; thus in a person who is injecting insulin, expect low glucose, high insulin and low C-peptide. Insulinoma would give high levels of both insulin and C-peptide (endogenous insulin). Sulphonylurea drugs make the Beta cells of the pancreas secrete insulin thus the lab tests will be similar to insulinoma; a urine toxicology screen for sulphonylurea drugs will clench the diagnosis. Glucagonoma presents with hyperglycemia and a characteristic rash (Necrolytic migratory erythema). Chronic pancreatitis may present with hyperglycemia and diabetes because of insulin deficiency. Please remember that the C-peptide is an endogenous substance which is not present in pharmaceutical insulin and you will answer all the tricky questions around this issue correct.

🇨🇦 MCCQE1,2 | #Case_169
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An otherwise healthy 40-year-old male comes to your office for follow-up of elevated liver enzymes on an insurance examination. He is 173 cm (68 in) tall and weighs 113 kg (250 lb) (BMI 37.7 kg/m²). He says he drinks about two beers per week. Findings are normal on a physical examination, except for a slightly enlarged liver. AST and ALT levels are twice the upper limits of normal. Which one of the following would be the most appropriate next step?

❤A liver biopsy
💛Ultrasonography of the liver
💚Colonoscopy
💙Testing for viral hepatitis
💜Repeat AST and ALT levels in 3 months

🇨🇦 MCCQE1,2 | #Case_169 | #answer
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✅ D

🔎 Explanation

Nonalcoholic fatty liver disease is the most likely diagnosis in this patient, but hepatitis B and C should be ruled out (choice D). The patient's alcohol consumption of less than two drinks per week makes alcoholic fatty liver disease unlikely.

⚠ A liver biopsy (choice A) would not be appropriate at this time.

⚠ Liver ultrasonography (choice B) should be considered after hepatitis B and C are ruled out.

⚠ The patient is younger than the recommended screening age for colonoscopy (choice C).

⚠ There is no rason to repeat previously repeated test results (lab error unlikely) (choice E).

🇨🇦 MCCQE1,2 | #Case_170
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A 32-year-old man presents with increased shortness of breath and he has had a cough for the past week. He appears dyspneic and has a temperature of 38.3°C (101.0°F). On physical examination he has bibasilar rales and generalized lymphadenopathy. Rectal examination shows multiple perianal contusions and a small amount of blood oozing from the anal orifice. Chest x-ray film shows bilateral patchy alveolar infiltrates. The most appropriate next step is:

❤Admit him to the hospital and begin administration of trimethoprim-sulfamethoxazole, intravenously

💛Admit him to the hospital and begin administration of penicillin and gentamicin, intravenously

💚Begin administration of erythromycin, orally, and see him again the next day

💙Prescribe isoniazid and rifampin, orally

💜Recommend aspirin, fluids and rest at home

🇨🇦 MCCQE1,2 | #Case_170 | #answer
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✅ A

🔎 Explanation

The history and physical raises the possibility of HIV infection. There is a strong suggestion of homosexuality, given that the rectal examination demonstrates multiple perianal contusions and blood oozing from the anal orifice. Furthermore, this
man has generalized lymphadenopathy; his chief complaint is of pulmonary distress with an x-ray consistent with Pneumocystis carinii pneumonia (PCP). Since the patient has become increasingly short of breath and is febrile, he should be treated with intravenous therapy. Treatment of choice for PCP is Bactrim (trimethoprim-sulfamethoxazole).

🇨🇦 MCCQE1,2 | #Case_171
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A 2-month-old male is brought in by his mother who has noted unusual sounds while the baby is breathing. She states that it started about weeks ago, but yesterday, it sounded like it was getting worse. The breathing noise is usually heard when the baby is lying on his back or crying, and it improves when she holds the baby on her shoulder. She also noticed that the sounds are worse when the baby is breathing in but they get better on exhalation. The pregnancy and delivery were uneventful and the baby had been growing well since birth. On physical examination you note stridor that increases on inspiration heard best just above the sternal notch. Which of the following is the most likely diagnosis?

❤Airway foreign body
💛Choanal atresia
💚Laryngotracheobronchitis
💙Subglottic stenosis
💜Laryngomalacia

🇨🇦 MCCQE1,2 | #Case_171 | #answer
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✅ E

🔎 Explanation

This patient presents with stridor that worsens on insepiration and when he is in the supine position, which is typical of laryngomalacia (choice E). It is a congenital abnormality of the laryngeal cartilage, the most common cause of congenital stridor and is the most common congenital lesion of the larynx. It is a dynamic lesion resulting in collapse of the supraglottic
structures during inspiration leading to airway obstruction. The epiglottis is curled on itself to form an omega-shaped epiglottis. 90% of cases heal by themselves by the age of 2 without any treatment. Diagnosis is best confirmed with laryngoscopy or bronchoscopy. In cases with the typical stridor that worsens when the child lies down, it is reasonable to make the diagnosis based on clinical presentation.

⚠ Airway foreign body (choice A) is seen in aspiration of objects by toddlers and pre school children. The presentation is acute with a child suddenly coughing or choking. New abnormal airway sounds are heard and are often unilateral. Stridor is heard during both phases of respiration, inspiration and expiration.

⚠ Choanal atresia (choice B) is a supralaryngeal cause of stridor with the back of the nasal passage blocked by abnormal bony or membranous tissue due to failed recanalization of the nasal fossae during fetal development. Bilateral choanal atresia is more serious than unilateral choanal atresia and crying alleviates respiratory distress.

⚠ Laryngotracheobronchitis (choice C) or Croup as it is commonly called, manifests as hoarseness, a seal-like barking cough, and a variable degree of respiratory distress.The most common cause of Croup is parainfluenza infection.

⚠ Subglottic stenosis (choice D) can be congenital or acquired. Stridor of subglottic stenosis is typically biphasic. Acquired forms usually arise from endotracheal intubation.

🔖 Key point:

Laryngomalacia is characterized by an immature cartilage that leads to collapse of the supraglottic structures during inspiration, and results in airway obstruction. Stridor that worsens when the child lies supine is typical and can be used to make a clinical diagnosis. The diagnosis is confirmed with bronchoscopy and laryngoscopy.

🇨🇦 MCCQE1,2 | #Case_172
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A 34-year-old female of Brazilian-Canadian origin, who works as an accountant, comes to the clinic complaining of difficulty swallowing both solid foods and liquids. It started 2 months ago but recently she feels that it is getting worse. She has noticed a 5 kg weight loss in the past 2 months. She also experiences heartburn and sometimes feels regurgitation of foods. Her past medical history is only remarkable for Chagas disease 20 years ago while she was a teenager living in Brazil. She denies smoking or drinking. What is the most accurate diagnostic method to confirm the diagnosis?

❤Esophagogastroduodenoscopy (EGD)
💛Chest plain radiography
💚Barium esophagography
💙Esophageal manometry
💜Response to proton pump inhibitors

🇨🇦 MCCQE1,2 | #Case_172 | #answer
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✅ D

🔎 Explanation

This woman presents with a history suggestive of achalasia. This is indicated by the dysphagia of both solids and liquids occurring simultaneously, regurgitation, weight loss, and her past history of Chagas disease. Achalasia is an esophageal
motility disorder characterized by the absence of esophageal peristalsis and impaired relaxation of the lower esophageal sphincter in response to swallowing. The vast majority is of unknown etiology while a small percentage can be from Chagas disease, gastric carcinoma, and lymphoma. The most accurate diagnostic test to confirm achalasia is esophageal manometry (choice D), which shows increased lower esophageal resting pressure.

⚠ Esophagogastroduodenoscopy (choice A) is done when cancer red-flag symptoms such as anemia, heme-positive stools, weight loss, symptoms longer than 6 months in a patient >60 years old are present.

⚠ Chest plain radiography (choice B) may show an air-fluid level in the dilated esophagus, but it is not accurate enough to confirm the diagnosis.

⚠ Barium esophagography (barium swallow) (choice C) is a very accurate test and shows dilation of the esophagus, which narrows into the classic “bird’s beak” at the distal end; however, this is not the most accurate test available. Choose barium swallow if esophageal manometry is not in the answer choices.

⚠ Response to proton pump inhibitors (choice E) is a common way to confirm gastroesophageal reflux disease (GERD).

🔖 Key Point:

Dysphagia of both solids and liquids simultaneously accompanied by regurgitation and weight loss in a patient with a history of Chagas disease suggests achalasia. Esophageal manometry is the most accurate diagnostic test while barium esophagography is the second best test to accurately diagnose this condition.

🇨🇦 MCCQE1,2 | #Case_173
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A 77-year-old white male complains of urinary incontinence of more than one year’s duration. The incontinence occurs with sudden urgency. No association with coughing or positional change has been noted. There is no history of fever or dysuria. One year ago he underwent transurethral resection of the prostate (TURP) for benign prostatic hypertrophy and says his urinary stream has improved. Rectal examination reveals a smoothly enlarged prostate without nodularity, and normal sphincter tone. No residual urine is found post-void catherterization. Which one of the following is the most likely cause of this patient’s incontinence?

❤Detrusor instability
💛Urinary tract infection
💚Overflow
💙Fecal impaction
💜Recurrent bladder outlet obstruction

🇨🇦 MCCQE1,2 | #Case_173 | #answer
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✅ A

🔎 Explanation

In elderly patients, detrusor instability is the most common cause of urinary incontinence in both men and women. Incontinence may actually become worse after surgical relief of obstructive prostatic hypertrophy. Infection is unlikely as the cause of persistent incontinence in this patient in the absence of fever or symptoms of urinary tract infection. Overflow is unlikely in the absence of residual urine. Impaction is a relatively rare cause of urinary incontinence, and associated findings would be present on rectal examination. Normalization of the urinary stream and the absence of residual urine reduce the likelihood of recurrent obstruction. The prostate would be expected to remain
enlarged on rectal examination after transurethral resection of the prostate (TURP).

🇨🇦 MCCQE1,2 | #Case_174
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A 27-year-old male presents to your department because he has been coughing up bloody sputum for the past 5 days. His past medical history is significant for recurrent rhinitis and sinusitis for many years, but according to the patient, they have been more frequent in the past 2 years. On physical examination saddle nose deformity is noted. Hematuria is observed on urinalysis. Further work-up reveals positive cytoplasmic anti-neutrophil cytoplasmic antibodies. What is the most likely diagnosis?

❤Churg-Strauss syndrome
💛Granulomatosis with polyangiitis
💚Goodpasture’s syndrome
💙Sarcoidosis
💜Cryoglobulinemia

🇨🇦 MCCQE1,2 | #Case_174 | #answer
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✅ B

🔎 Explanation

This patient presents with hemoptysis and hematuria, which suggest pulmonary and renal disease. Given the patient’s history of recurrent rhinitis and sinusitis and the positive cytoplasmic antineutrophil cytoplasmic antibodies, the most likely diagnosis is granulomatosis with polyangiitis (choice B) formerly known as Wegener’s granulomatosis. It is a multisystem autoimmune disease of unknown etiology characterized by necrotizing granulomatous inflammation and pauci-immune vasculitis in small- and medium-sized blood vessels. Diagnosis is generally confirmed with tissue biopsy from a site of active disease; renal and lung biopsies are most specific for granulomatosis with polyangiitis.

⚠ Churg-Strauss syndrome (choice A) is an allergic granulomatous angiitis that presents with asthma, paranasal sinusitis, and rapidly progressive glomerulonephritis. Eosinophilia is a common finding and perinuclear-ANCA
(antimyeloperoxidase antibodies) are better diagnostic markers than c-ANCA.

⚠ Goodpasture’s syndrome (choice C) causes acute glomerulonephritis and pulmonary hemorrhage due to the presence of circulating anti-glomerular basement membrane antibodies.

⚠ Sarcoidosis (choice D) a multisystem inflammatory disease of unknown etiology that manifests as noncaseating granulomas, predominantly in the lungs and intra-thoracic lymph nodes. Black people have increased risk of developing
this disease. It is not associated with cytoplasmic anti-neutrophil cytoplasmic antibodies.

⚠ Cryoglobulinemia (choice E) is characterized by the presence of cryoglobulins in the serum. Cryoglobulins are single or mixed immunoglobulins that undergo reversible precipitation at low temperatures. Studies have shown close association of this condition with Hepatitis C.

🔖Key point:

Granulomatosis with polyangiitis is a multisystem necrotizing granulomatous inflammation that often presents with respiratory and renal involvement with symptoms such as hemoptysis and hematuria. Cytoplasmic anti-neutrophil cytoplasmic antibodies are commonly present and biopsy is diagnostic of this condition

🇨🇦 MCCQE1,2 | #Case_175
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A 72-year-old white female is scheduled to undergo a total knee replacement for symptomatic osteoarthritis. She is otherwise healthy, with no history of vascular disease or deep vein thrombosis. She takes no routine medications. Which one of the following is most appropriate for prophylaxis against deep vein thrombosis?

❤No prophylaxis if there are no surgical complications
💛Aspirin, 325 mg daily
💚Unfractioned heparin, 5000 U subcutaneously every 12 hours
💙Thigh-high compression stockings
💜Enoxaparin (Lovenox), 30 mg subcutaneously every 12 hours

🇨🇦 MCCQE1,2 | #Case_175 | #answer
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✅ E

🔎 Explanation

Prophylaxis is indicated with total knee or hip replacements. The two regimens recommended are low-molecular-weight heparin and adjusted-dose warfarin. These may be augmented by intermittent pneumatic compression

🇨🇦 MCCQE1,2 | #Case_176
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At a prenatal visit at 12 weeks gestation a 38-year-old gravida 3 para 2 has a pulse rate of 110 beats/min and has lost 2 kg (4 lb) since her previous visit. At age 26, she was treated for Graves’ disease with radioactive iodine and has been euthyroid on no medication for over 10 years. A CBC shows a mild anemia. Her hematocrit is 34% (N 35-45) and her TSH level is 0.00 U/mL (N 0.5-5.0). Which one of the following would be most appropriate at this time?

❤Propylthiouracil
💛Propylthiouracil plus levothyroxine
💚Methimazole
💙Radioactive iodine therapy
💜Propranolol

🇨🇦 MCCQE1,2 | #Case_176 | #answer
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✅ A

🔎 Explanation

Graves disease is an autoimmune disease characterized by hyperthyroidism due to circulating autoantibodies. Mild hyperthyroidism (slightly elevated thyroid hormone levels, minimal symptoms) often is monitored closely without therapy as long as both the mother and the baby are doing well. When hyperthyroidism is severe enough to require therapy, anti-thyroid medications are the treatment of choice, with propylthiouracil (PTU) being the drug of choice. PTU is usually prescribed in the first trimester (up to week 14), and Methimazole (MMI) for the rest of the pregnancy. Thyroid surgery is rarely an option for pregnant women.

⚠ The combination of propylthiouracil and levothyroxine is frequently used for hyperthyroidism in nonpregnant patients, but transplacental passage of the levothyroxine would be harmful to the developing fetus.

⚠ Methimazole (MMI) crosses the placenta more readily than propylthiouracil and is associated with aplasia cutis. In areas where PTU is not available, or when a woman is allergic to PTU, methimazole and carbimazole are used during pregnancy,

⚠ Radioactive iodine therapy is contraindicated in pregnancy, and immediate surgery might present hazards to both the mother and the fetus.

⚠ Propranolol would control the patient’s heart rate, but would do nothing about the underlying hyperthyroidism

🇨🇦 MCCQE1,2 | #Case_177
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A 48-year-old female with type 2 diabetes has been hospitalized for 4 days with persistent fever. Her diabetes has been controlled with diet and glyburide. You saw her 2 weeks ago in the office with urinary frequency, urgency, and dysuria. At that time a urinalysis showed 25 WBCs/hpf, and a urine culture subsequently grew Escherichia coli sensitive to all antibiotics. She was placed on trimethoprim/ sulfamethoxazole empirically, and this was continued after the culture results were reported. She improved over the next week, but then developed flank pain, fever to 39.5°C (103.1°F), and nausea and vomiting. She was hospitalized and intravenous cefazolin and gentamicin were started while blood and urine cultures were performed. This urine culture also grew E. coli sensitive to the current antibiotics. Her temperature has continued to spike to 39.5°C since admission, without any change in her symptoms. Which one of the following would be most appropriate at this time?

❤Add vancomycin to the regimen
💛Order a radionuclide renal scan
💚Order intravenous pyelography
💙Order a urine culture for tuberculosis
💜Order CT of the abdomen