🇨🇦 MCCQE1,2 | #Case_114
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A 35-year-old male consults you about a vague chest pain he developed while sitting at his desk earlier in the day. The pain is right-sided and was sharp for a brief time when it began, but it rapidly subsided. There was no hemoptysis and the pain does not seem pleuritic. His physical examination, EKG, and oxygen saturation are unremarkable. A chest film shows a 10% right pneumothorax. Which one of the following is true in this situation?

a) He is likely to be an overweight smoker with a chronic cough
b) Rupture of subpleural bullae would be an unlikely cause of his problem
c) Outpatient observation with a repeat chest radiograph in 24 hours is indicated
d) A chest tube should be placed expeditiously
e) After treatment his probability of recurrence is less than 15%

🇨🇦 MCCQE1,2 | #Case_114 | #answer
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✅ C

🔎 Explanation

The majority of patients presenting with spontaneous pneumothorax are tall, thin individuals under 40 years of age. Most do not have clinically apparent lung disease, and the chest pain is sometimes minimal at onset and may resolve within 24 hours even if untreated. Patients with small pneumothorax involving less than 15% of the hemithorax may have a normal physical examination, although tachycardia is occasionally noted. The diagnosis is confirmed by chest radiographs. Studies of recurrence have found that an average of 30% of patients will have a recurrence within 6 months to 2 years. The treatment of an initial pneumothorax of less than 20% may be monitored if a patient has few symptoms. Follow-up should include a chest radiograph to assess stability at 24-48 hours. Indications for treatment include progression, delayed expansion, or the development of symptoms. The majority of patients with spontaneous pneumothoraces, and perhaps almost all of them, will have subpleural bullae on a CT scan.

🇨🇦 MCCQE1,2 | #Case_115
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A 50-year-old known hypertensive man was brought to the emergency department after a sudden feeling of numbness and weakness of his left arm and left half of the face. No other symptoms could be elicited and the patient could engage in dialogue, normally. Vital signs including blood pressure were stable. Left shoulder, upper arm, forearm and hand muscles have power of 2. Pain and temperature sensations are impaired on the left arm and left side of the face. No motor or sensory impairment could be detected on the right side or left lower side of the body. Visual fields were normal. The rest of physical examination was normal. Ischemic stroke was suspected. Which of the following arteries is the most likely site of blockage?

a) Right middle cerebral artery
b) Superior division of right middle cerebral artery
c) Inferior division of right middle cerebral artery
d) Lenticulostriate branches of the right middle cerebral artery
e) Right anterior cerebral artery

🇨🇦 MCCQE1,2 | #Case_115 | #answer
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✅ B

🔎 Explanation

The superior division of the right middle cerebral artery (MCA) (choice B) is the most likely site of blockage in this
patient. Patients with blockage of this division of MCA usually present with contralateral weakness and sensory loss on the arm and face. This division of the right MCA supplies the lateral surface of the right cerebral hemisphere above the lateral fissure but short of the superolateral portions, which are supplied by the anterior cerebral artery (ACA). Thus, motor, sensory and sensory association areas for the left upper part of the body (arm and face) are supplied by this division of MCA and weakness and sensory impairment are expected to affect these parts of the body. The lower limb is spared because its motor and sensory representation is located in the superolateral of frontal and parietal lobes which are supplied by the ACA. Because the right or non-dominant hemisphere is affected, our patient does not have any form of aphasia.

⚠ Patients with MCA blockage (choice A) usually present with symptoms and signs of blockage of its superior division (choice B), inferior division (choice C) and lenticulostriate division (choice D). Thus, these patients are expected to present with left sided weakness and hemianesthesia affecting the face, arm, and leg. Because the non-dominant right hemisphere is affect, hemi-neglect, astereognosis and anosognosia, hemianopsia rather than aphasia are also present.

⚠ Patients with inferior division of right middle cerebral artery (MCA)blockage (choice C) usually present with left sided homonymous hemianopsia because this artery supplies the parts of optic pathway that pass through the temporal lobe. Because the non-dominant hemisphere is affected, hemi-neglect, astereognosis, and anosognosia rather than aphasia accompanies the hemianopsia.

⚠ Patients with blockage of lenticulostriate branches of the right MCA(choice D) usually present with left sided hemianesthesia and hemiparesis of the leg, arm, and face. The lenticulostriate branches of the right MCA together with anterior choroidal artery supply the posterior limb of the internal capsule on the right where the motor and sensory fibers pass between the cortex and brain stem. Because motor and sensory fibers for both upper and lower parts of the body come close to each other, both of these parts of the body are affected.

⚠ Patients with right anterior cerebral artery (ACA) blockage (choice E) usually present with left sided hemianesthesia
and hemiparesis of the leg. The right ACA supplies the superolateral portions of the right frontal and parietal lobes, which due homunculus topography, contains the motor and sensory areas of the lower part of the body (leg). The arms and the face are usually not affected by blockage of the ACA because cortical areas representing these parts of the body are located along the lateral surface of the cerebral hemisphere and are supplied by superior division of MCA.

🔖Key point:

Weakness and anesthesia of the left arm and left half of the face and sparing of the lower leg is most likely caused by
blockage in the territory of the middle cerebral artery (MCA) other than the lenticulostriate division. Absence of hemi-neglect and hemianopsia exclude blockage of the inferior division and favours blockage of the superior division of the right MCA

🇨🇦 MCCQE1,2 | #Case_116
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A 47-year-old female presents with progressive difficulty hearing. She is employed as an office worker, has no significant past medical history, and takes no medications. Physical examination shows no gross abnormalities of her outer ears. The external ear canals are free of cerumen, and the tympanic membranes move well to insufflation. Weber’s test and the Rinne test have results that are compatible with a conductive hearing loss. Which one of the following is the most likely cause of this patient’s hearing loss?

a) Noise-induced hearing loss
b) Meniere’s disease
c) Otosclerosis
d) Acoustic neuroma
e) Perilymphatic fistula

🇨🇦 MCCQE1,2 | #Case_116 | #answer
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✅ C

🔎 Explanation

Otosclerosis typically presents between the third and fifth decades, and is more common in women. The chief feature of
otosclerosis is a progressive conductive hearing loss. Occasionally, when lesions impinge on the stapes footplate, a sensorineural loss may occur. All of the other choices are exclusively sensorineural in character. Meniere’s disease also causes fluctuating hearing loss. Noise-induced hearing loss frequently and characteristically is accompanied by tinnitus. Perilymphatic fistula is associated with sudden unilateral hearing loss with tinnitus and vertigo. Acoustic neuroma is associated with tinnitus and gradual hearing impairment

🇨🇦 MCCQE1,2 | #Case_117
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A 15-year-old female is brought to the hospital by her mother because she has never had menstrual periods and the mother is concerned. On physical examination the girl appears short, has a webbed neck. Four-limb blood pressures were also evaluated: higher blood pressures were noted in the arms while the ones of the lower extremities were normal. Which of the following is the best way to confirm this girl’s diagnosis?

a) Echocardiography
b) FSH, LH, and Estrogen levels
c) Karyotype
d) Brain MRI
e) Bone age assessment

🇨🇦 MCCQE1,2 | #Case_117 | #answer
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✅ C

🔎 Explanation

This girl has primary amenorrhea, a webbed neck, and a significant difference between the blood pressure in the upper and lower extremities (suggesting possible coarctation of the aorta). These findings suggest Turner syndrome as the most likely diagnosis. The best way to confirm this diagnosis is a standard 30 cell Karyotype, which in Turner syndrome would reveal 45, XO cell line or a cell line with deletion of the short arm of the X chromosome.

⚠ An echocardiography (choice A) is useful in evaluating cardiovascular abnormalities of Turner syndrome such as the coarctation of the aorta; while this is an important characteristic of Turner syndrome, it is not the best way to confirm it.

⚠ FSH, LH, and Estrogen (choice B) are likely to be abnormal in this patient. With estrogen being low while FSH and LH are elevated; this, however, is not the best way to confirm Turner syndrome.

⚠ Brain MRI (choice D) would be useful in cases of amenorrhea caused by pituitary pathology such as craniopharyngioma, it is not the best way to confirm Turner syndrome.

⚠ Bone age assessment (choice E) will be useful in the management of this patient as hormone therapy is being considered; however, this is not the best way to confirm Turner syndrome.

🔖 Key point:

When Turner syndrome is suspected, Karyotype is the best way to confirm it.

🇨🇦 MCCQE1,2 | #Case_118
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A 27-year-old man with advanced HIV is sent for evaluation of his nephrotic syndrome. His blood pressure is 142/84 mm Hg. He has 3+ edema in both legs. His risk factor for AIDS is his IV heroin use. His creatinine is 2.1 mg/dL, and his urine reveals +3 protein, no blood. A kidney biopsy would most likely reveal which of the following?

a) Diabetic nephropathy
b) Focal glomerular sclerosis
c) IgA nephropathy
d) Membranous nephropathy
e) Minimal change disease

🇨🇦 MCCQE1,2 | #Case_118 | #answer
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✅ B

🔎 Explanation

Focal glomerular sclerosis is the type of nephropathy most commonly seen in IV drug users with AIDS. It is likely to lead to a very rapid loss of renal function.There is no clinical evidence to indicate that this person has diabetes, making diabetic nephropathy unlikely. Minimal change disease and IgA nephropathy and membranous nephropathy are only very rarely associated with AIDS.

🇨🇦 MCCQE1,2 | #Case_119
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For two weeks, a 62-year-old male with biopsy-documented cirrhosis and ascites has had diffuse abdominal discomfort, fever, and night sweats. His current medications are furosemide (Lasix) and spironolactone (Aldactone). On examination, his temperature is 38.0°C (100.4°F), blood pressure 100/60 mm Hg, heart rate 92 beats/min and regular. The heart and lung examination is normal. The abdomen is soft with vague tenderness in all quadrants. There is no rebound or guarding.
The presence of ascites is easily verified. Bowel sounds are quiet. The rectal examination is normal, and the stool is negative for occult blood. You perform diagnostic paracentesis and send a sample of fluid for analysis.
Which one of the following findings would best establish the suspected diagnosis of spontaneous bacterial peritonitis?

a) pH < 7.2
b) Bloody appearance
c) Neutrophil count > 300/mL
d) Positive cytology
e) Total protein > 1 g/dL

🇨🇦 MCCQE1,2 | #Case_119 | #answer
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✅ C

🔎 Explanation

Diagnostic paracentesis is recommended for patients with ascites of recent onset, as well as for those with chronic ascites who present with new clinical findings such as fever or abdominal pain. A neutrophil count > 250/mL is diagnostic for peritonitis. Once peritonitis is diagnosed, antibiotic therapy should be started immediately without waiting for culture results. Bloody ascites with abnormal cytology may be seen with hepatoma, but is not typical of peritonitis. The ascitic fluid pH does not become abnormal until well after the neutrophil count has risen, so it is a less reliable finding for treatment purposes. A protein level > 1 g/dL is actually evidence against spontaneous bacterial peritonitis

🇨🇦 MCCQE1,2 | #Case_120
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A 35-year-old male complains of 2 months of right shoulder pain. He does not recall an injury, but says it is painful to lie on his right side or to work with his right hand above his head. On examination, the shoulder appears normal and there is no pain with external rotation of the shoulder, bringing the arm across the body (scarf test), or attempted external and internal rotation of the shoulder against resistance. Lowering the arm from full abduction (painful arc), attempted abduction above 45° against resistance, and elevating the internally rotated arm above 90° against resistance are all painful.The most likely diagnosis is:

a) Subdeltoid bursitis
b) Adhesive capsulitis
c) Impingement syndrome
d) Glenohumeral osteoarthritis
e) Acromioclavicular osteoarthritis

🇨🇦 MCCQE1,2 | #Case_120 | #answer
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✅ C

🔎 Explanation

The combination of a painful arc and pain on use of the supraspinatus muscle indicates impingement syndrome (also called painful arc syndrome, supraspinatus syndrome, swimmer's shoulder, and thrower's shoulder), which is due to irritation of the rotator cuff under the coracoacromial arch. It is by far the most common cause of shoulder pain seen by family.

⚠ Subdeltoid bursitis is a much more acute problem, and impairs shoulder mobility in all directions.

⚠ Adhesive capsulitis produces loss of external rotation.

⚠ Glenohumeral arthritis produces pain with external rotation, and variable amounts of impaired mobility, depending on progression of the problem over time.

⚠ Acromioclavicular joint arthritis produces a positive scarf sign, and often a visible bump over the joint, since it lies so close to the skin surface

🇨🇦 MCCQE1,2 | #Case_121
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A 76-year-old female is hospitalized for fever and weakness of several days’ duration. Her history and physical findings are otherwise unremarkable except for a temperature of 38.2°C (100.8°F), a pulse rate of 100 beats/min, and a blood pressure of 110/70 mm Hg. A urinalysis reveals 10-15 WBCs/hpf and a urine culture reveals methicillin-sensitive Staphylococcus aureus. The most appropriate action at this point is to:

a) reculture the urine, as the bacteria on the first urine culture is most likely a skin contaminant
b) obtain a blood culture and examine the patient for a portal of entry
c) obtain a blood culture and start the patient on intravenous vancomycin (Vancocin)
d) start the patient on oral cephalexin (Keflex)
e) order echocardiogram

🇨🇦 MCCQE1,2 | #Case_121 | #answer
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✅ B

🔎 Explanation

Staphylococcus aureus is an unusual genitourinary pathogen; when found in the urine, it should be assumed to have migrated from a primary location. The patient should be examined carefully for a portal of entry such as a skin ulcer, intravenous site, or area of dermatitis.

⚠ An echocardiogram is often required to rule out endocarditis.

⚠ Methicillin-sensitive S. aureus can be treated with a penicillinase-resistant penicillin or a first-generation
cephalosporin.

⚠ Vancomycin should be reserved for treating methicillin-resistant S. aureus.

⚠ Although oral cephalexin can be used to treat methicillin-sensitive S. aureus, this particular patient is too ill and needs to be evaluated for bacteremia

🇨🇦 MCCQE1,2 | #Case_122
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A 72-year-old Asian-Canadian female is brought to your office by her husband because he thinks she might have Alzheimer’s disease. For the past 3 months she has complained of confusion, poor appetite, and lack of energy. She has been unable to do routine housework. On brief questioning, her short-term recall seems to be impaired, but a more detailed examination indicates that her memory is fine.Which one of the following is the most likely diagnosis?

a) Alzheimer’s disease
b) Lewy body dementia
c) Frontotemporal dementia
d) Pseudodementia
e) Mild cognitive impairment

🇨🇦 MCCQE1,2 | #Case_122 | #answer
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✅ D

🔎 Explanation

Instead of dementia, this patient has signs of pseudodementia of depression, which usually has a subacute onset. Memory usually is intact when adequate time is taken to carefully evaluate the patient.

⚠ The onset of Alzheimer’s disease, however, is gradual and includes memory loss.

⚠ Lewy body dementia is associated with hallucinations, and the onset is gradual.

⚠ Frontotemporal dementia generally occurs before age 60. Memory is usually preserved for orientation, although information retrieval may be difficult.

⚠ The onset of mild cognitive impairment is gradual and includes memory loss.

🇨🇦 MCCQE1,2 | #Case_123
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A 43-year-old female with a known history of migraines comes to your office today complaining of unusual chest pains. There is no family history of any coronary artery disease and she is neither a smoker nor does she have hypertension. She describes the discomfort occurring at times of rest and during exertion. However the episodes vary and arise unexpectedly. She is otherwise healthy with no other complaints. Which of the following is contraindicated in this patient?

a) Nifedipine
b) Sumatriptan
c) Lisinopril
d) Verapamil
e) Flunarizine

🇨🇦 MCCQE1,2 | #Case_123 | #answer
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✅ B

🔎 Explanation

This female has Prinzmetal variant angina, which is caused by coronary vasospasms. Sumatriptan is a 5HT1D and 1B agonist, which will have a vasoconstrictive effect. A side effect of this particular drug is that it induces vasospasms, hence contraindicated in individuals with this particular angina

🇨🇦 MCCQE1,2 | #Case_124
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A 65-year-old diabetic male comes to the office complaining of excruciating pain in his left ear that began last night. The pain is 10/10 in intensity and radiates to his mandible. He also complains of ear discharge along with the pain. His condition is worsening progressively despite the use of Tobradex™ ear drops (Tobramycin + dexamethasone). Review of systems is otherwise normal. His vitals signs are within normal limits except for a temp of 38°C. HEENT exam shows the presence of granulation tissue in the lower part of his external auditory canal at the junction between the cartilaginous and bony parts of the canal. When the patient is asked to smile, some weakness of the left facial nerve is noticed. Which of the following pathogens is most likely to be responsible for this patient’s condition?

a) Aspergillus nigrican
b) Escherichia coli
c) Pseudomonas aeruginosa
d) Streptococcus pneumonia
e) Streptococcus pyogenes