🇨🇦 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

🇨🇦 MCCQE1,2 | #Case_177 | #answer
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✅ E

🔎 Explanation

Perinephric abscess is an elusive diagnostic problem that is defined as a collection of pus in the tissue surrounding the kidney, generally in the space enclosed by Gerota’s fascia. Mortality rates as high as 50% have been reported, usually from failure to diagnose the problem in a timely fashion. The difficulty in making the diagnosis can be attributed to the variable constellation of symptoms and the sometimes indolent course of this disease. The diagnosis should be considered when a patient has fever and persistence of flank pain. Most perinephric infections occur as an extension of an ascending urinary tract infection, commonly in association with renal calculi or urinary tract obstruction. Patients with anatomic urinary tract abnormalities or diabetes mellitus have an increased risk. Clinical features may be quite variable, and the most useful predictive factor in distinguishing
uncomplicated pyelonephritis from perinephric abscess is persistence of fever for more than 4 days after initiation of antibiotic therapy. The radiologic study of choice is CT. This can detect perirenal fluid, enlargement of the psoas muscle (both are highly suggestive of the diagnosis), and perirenal gas (which is diagnostic). The sensitivity and specificity of CT is significantly greater than that of either ultrasonography or intravenous pyelography. Drainage, either percutaneously or surgically, along with appropriate antibiotic coverage reduces both morbidity and mortality from this condition

🇨🇦 MCCQE1,2 | #Case_178
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A 45-year-old woman presented to hospital with fatigue and muscle pain. She was feeling fatigue for the last 10 to 12 months. Seven months ago she was prescribed iron because she had mild iron deficiency anemia. No other symptoms could be elicited. The patient is not a known diabetic or hypertensive and was not on any medication. The patient looked well, not pale, jaundiced or cyanosed. Her body mass index was 36. Body temperature was normal, heart rate 83 per minute and blood pressure 151/116 mm Hg. Cardiac and chest examination were normal and her muscles were not tender. No edema could be demonstrated in the lower limbs or sacrum. Lab investigation results were as follows:
Complete blood count and ESR were normal
Sodium 144 mmol/L
Potassium 2.9 mmol/L
Creatinine 63 µmol/L
Blood urea nitrogen (BUN) 3.6 mmol/L Diagnosis of hyperaldosteronism is strongly suspected and measurement of plasma aldosterone and plasma renin activity was contemplated. Before doing this test you should:

a) Perform adrenal CT scan
b) Normalize plasma potassium level
c) Control the blood pressure
d) Load patient with sodium orally
e) Load patient with sodium intravenously

🇨🇦 MCCQE1,2 | #Case_178 | #answer
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✅ B

🔎 Explanation

The two major controllers of aldosterone secretion are the renin-angiotensin-system and plasma potassium level. The kidneys produce the enzyme renin in response to reduction in effective renal blood flow (caused, for example, by hemorrhage or heart failure). Renin in turn splits a plasma protein called angiotesniongen to produce angiotensin which stimulates the adrenal cortex to produce aldosterone. High plasma potassium directly stimulates and low potassium inhibits release of aldosterone by the adrenal cortex. Thus, plasma aldosterone level is a function of plasma potassium level. To avoid false negative results in patients suspected of having hyperaldosteronism, plasma potassium should thus, be normalized first (choice B) before measurement of plasma aldosterone and renin activity.

⚠ Adrenal CT scan (choice A) is used to find whether primary hyperaldosteronism is caused by adrenal adenoma or bilateral idiopathic hyperplasia. This is a later step in the diagnosis and should be done only when the diagnosis of primary hyperaldosteronism is confirmed.

⚠ Control of blood pressure (choice C) is not required. Indeed, drugs commonly used in treatment of hypertension like diuretics, angiotensin converting enzyme inhibitors and beta-blockers can interfere with measurement of aldosterone and plasma renin activity. However, the blood pressure should be controlled because it is high but not necessarily before performing the test.

⚠ Loading this patient with sodium orally (choice D) or intravenously (choice E) is contraindicated in this patient because he has severe hypertension and a hypertensive emergency can be precipitated by this.

🔖Key point:

Plasma potassium levels should be normalized prior to investigation of hyperaldosteronism (to avoid false negative results)

🇨🇦 MCCQE1,2 | #Case_179
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A 26-year-old male comes to your office complaining of hiccups. He refers to you that the bout began 2 hours ago, and has not stopped since. He does not report any remarkable medical history, does not drink alcohol or smoke, carries a healthy lifestyle and does not have any other symptoms, other than the hiccups. Physical examination is unremarkable other than obvious hiccups. Vital signs are within normal limits. Which of the following would be considered the first line therapy for this particular patient?

a) Initiate vagal maneuvers
b) Chlorpromazine
c) Metoclopramide
d) Baclofen
e) Acupuncture

🇨🇦 MCCQE1,2 | #Case_179 | #answer
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✅ A

🔎 Explanation

The first line therapy in a patient with hiccups when no cause can be identified is physical maneuvers. Asides from being easy to perform, they are safe and in many cases effective to stop the bout. Examples of physical maneuvers for the treatment of hiccups are:

🔹 Interrupting the respiratory cycle (breath holding)
🔹 Valsalva maneuver
🔹 Catheter or cotton swab stimulation of nasooropharynx
🔹 Vagal maneuvers (choice A) - Pressing on the eyeballs, putting an ice bag on the forehead.
🔹 Counteract irritation of the diaphragm - knees to chest or leaning forward to compress the chest

Pharmacological therapy is reserved for hiccups when physical therapy has failed. This is because the medications that have proven to be effective can have serious adverse effects. The pharmacological therapy includes the following medications:

⚠ Chlorpromazine (choice B) - the most widely used medication used to treat hiccups, regarded as the most effective. It can cause dystonic reactions and drowsiness on short term use, and tardive dyskinesia.

⚠ Metoclopramide (choice C) - has also proven to be effective in large case series. It is associated with tardive
dyskinesia, especially in long term use and high doses.

⚠ Baclofen (choice D) - is a muscle relaxant. It is effective in the treatment of hiccups, although it causes drowsiness and its effectiveness has only been proven in a few small case series.

⚠ When physical therapy and pharmacological therapy fail, the use of complementary medicine is available for the treatment of hiccups. Acupuncture (choice E) has been reported to be effective to treat hiccups in a small study.

🔖 Key point:

Physical therapy in the management of a bout of hiccups without an identified cause is the first line therapy of treatment. This is important to know as the medications used to treat hiccups carry adverse effects that can be avoided if physical therapy is effective

🇨🇦 MCCQE1,2 | #Case_180
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A 71-year-old male presents to your department for hypertension management follow-up. He denies any symptoms. He is known to have refractory hypertension and his current antihypertensive drugs include furosemide, ramipril, metoprol, and doxazosin. He smoked 40 packs of cigarettes a year for 30 years but quit smoking 10 years ago. Physical examination reveals temperature 37.3°C, BP 170/100 mmHg, pulse is 90 bpm, respirations 14/min. An abdominal bruit is heard on auscultation. Dupplex ultrasonographic scanning suggests renal artery stenosis while digital subtraction angiography reveals a 90% occlusion of the left renal artery. The patient is scheduled to undergo surgical revascularization. Which of the following options best states the pathophysiology of this patient’s disease in its early phase? [I-increased, D-decreased]

a) Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion [ I ]; GFR [ I ]; Renal blood flow [ I ]
b) Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ D ]; Na+ excretion [ D ]; GFR [ D ]; Renal blood flow [ I ]
c) Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion [ D ]; GFR maintained; Renal blood flow [ I ]
d) Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion [ D ]; GFR maintained; Renal blood flow [ D ]
e) Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion maintained; GFR [ D ]; Renal blood flow [ I ];

🇨🇦 MCCQE1,2 | #Case_180 | #answer
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✅ D

🔎 Explanation

This patient’s refractory hypertension history and the imaging studies results clearly point to the diagnosis of renal artery stenosis. The best non-invasive study to diagnose this condition is duplex ultrasonographic scanning while the gold standard test remains digital subtraction angiography. In patients >50 years old the most common cause of renal artery stenosis is atherosclerosis. Renal artery stenosis results in kidney hypoperfusion, which leads to the release of abnormally high levels of renin. This will increase systemic angiotensin II and aldosterone levels, which will cause widespread vasoconstriction and significant Na+ and water retention by both normal and abnormal kidney. Both these actions result in increased blood pressure. Angiotension II has a preferential action on the efferent arterioles this allows it to maintain GFR despite reduced renal perfusion. Although vasoconstriction of the efferent arterioles further decreases renal blood flow, it also increases hydrostatic pressure of the glomerulus, which increases the net filtration pressure of the glomerulus and maintains the GFR. This makes choice D with increased renin, increased angiotensin, elevated aldosterone, decreased Na+ excretion
(increased retention), maintained GFR, and decreased renal blood flow the best answer.

⚠ Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion [ I ]; GFR [ I ]; Renal blood flow [ I ] (choice A) is incorrect. Na+ excretion is reduced as salt retention increases and the renal blood flow is reduced.

⚠ Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ D ]; Na+ excretion [ D ]; GFR [ D ]; Renal blood flow [ I ] (choice B) is incorrect because aldosterone increases and renal blood flow decreases.

⚠ Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion [ D ]; GFR maintained; Renal blood flow [ I ] (choice C) is incorrect because renal blood flow is decreased in renal artery stenosis, not increased.

⚠ Renin [ I ]; Angiotensin II [ I ]; Aldosterone [ I ]; Na+ excretion maintained; GFR [ D ]; Renal blood flow [ I ](choice E) is incorrect because Na+ retention is increased while Na+ excretion is decreased.

🔖Key point:

In renal artery stenosis renal hypoperfusion leads to the release of high levels of renin, which results in high levels of angiotensin II and aldosterone. This subsequently increases Na+ and water retention. GFR is maintained in the early phase of this disease

🇨🇦 MCCQE1,2 | #Case_181
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A 45-year-old woman with an unremarkable past medical history was found to have an elevated serum alkaline phosphatase (ALP) of four times the normal value. Serum bilirubin, aspartate and alanine transaminases, albumin and coagulation profile were within their normal limits. Which of the following investigations should be done next?

a) Radionuclide bone scan
b) Serum osteocalcin
c) Serum calcium and phosphate
d) Serum 5’-nucleotidase
e) Endoscopic retrograde cholangiopancreatography (ERCP)