🇨🇦 MCCQE1,2 | #Case_158 | #answer
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✅ E

🔎 Explanation

The patient has a history and symptoms very suggestive of a compartment syndrome of the anterior compartment of the left leg. A common cause of this serious problem is limb compression during prolonged recumbency related to drug or alcohol overdose. Early diagnosis and treatment are essential in order to avoid permanent, severe disability. The five “P’s” of compartment syndrome are pain, pallor, paresthesias, pulselessness, and paralysis. If distal pulses are reduced, then muscle necrosis has occurred and immediate surgical consultation is necessary. Duplex Doppler ultrasonography and impedance plethysmography are used to evaluate for deep venous thrombosis. Given the decreased pulses, however, this diagnosis is much less likely and such testing may needlessly delay urgent surgical treatment. Intravenuous antibiotics would be appropriate for cellulites. This diagnosis is unlikely in this scenario given the absence of fever, erythema, and edema, and the presence of a diminished pulse. Rest, ice, and elevation are inappropriate treatment modalities for compartment syndrome.

🇨🇦 MCCQE1,2 | #Case_158
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A 28-year-old previously healthy female presents with a 2-day history of a painful mass on her vulva. On examination vital signs are normal. The patient is unable to sit normally because of the pain. She has an exquisitely tender red mass in the posterior right labia majora. It is oval in shape, with the largest dimension being about 6 cm. The treatment of choice for this condition would be:

❤Marsupialization of the lesion
💛Surgical excision
💚Surgical gland removal
💙Incision and packing with iodoform gauze
💜Incision and insertion of a word catheter

🇨🇦 MCCQE1,2 | #Case_159 | #answer
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✅ E

🔎 Explanation

The patient has a Bartholin’s abscess. Abscesses may present spontaneously or after a painless cyst with the following symptoms:

•Acute, painful unilateral labial swelling
•Dyspareunia
•Pain with walking and sitting
•Sudden relief of pain followed by discharge (highly suggestive of spontaneous rupture)

Incision of the lesion, followed by insertion of a Word catheter, creates a long-lasting drainage tract and usually cures the problem permanently.

⚠ Marsupialization can be used for a Bartholin’s cyst, but is not appropriate for an acutely infection lesion like the one presented. This procedure is reserved for recurrent abscesses.
⚠ Surgical excision is used for recurrent, but not acutely infected, cysts.
⚠ Incision and drainage alone relieves the immediate pain, but is associated with a very high recurrence rate.
⚠ Surgical gland removal is rarely used

🇨🇦 MCCQE1,2 | #Case_160
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A 29-year-old man presents to the ED with recent onset of double vision when looking to his right. His partner has
noticed that his eye movements are uncoordinated and the right eye is moving abnormally when he attempts to look to his right. He also complains of increased fatigability and several episodes of bed-wetting since last month. He has no other medical problems and is not on any medication.On attempted right gaze, the left eye showed deficient adduction while the right eye showed repetitive, rapid, horizontal, jerky movements with the fast phase toward the right side. Both eyes showed normal convergence to a near target. Rest of the neurological and general system examination was normal. What is the most likely etiology of his symptoms and signs?

❤Tumor of the brainstem
💛Vascular malformation of the brainstem
💚Metastatic deposits in the brainstem
💙Atherosclerosis
💜Demyelinating disease

🇨🇦 MCCQE1,2 | #Case_160 | #answer
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✅ E

🔎 Explanation

This patient’s eye movement abnormalities (horizontal gaze palsy; adduction deficit in the left eye and ataxic nystagmus in the right eye on attempted right gaze) are compatible with a left internuclear ophthalmoplegia (INO). INO indicates midbrain pathology. However, a structural lesion in the midbrain wouldn’t explain the constitutional symptoms and incontinence seen in this patient. Demyelinating disease (option E) such as Multiple Sclerosis (MS) can present as INO and can also cause constitutional symptoms and incontinence.

⚠ Localize lesions of the brainstem such as a tumor of the brainstem (choice A) and vascular malformation of the brainstem (choice B) wouldn’t explain the constitutional symptoms and incontinence seen in this patient.

⚠ Metastatic deposits in the brainstem (choice C) and atherosclerosis (choice D) can cause an INO; however, is unlikely in a young patient who has been otherwise healthy.

🔖 Key point:

Demyelinating disease (Multiple Sclerosis) can present with spatially and temporally unrelated neurological symptoms. INO in a young patient is a common ophthalmic manifestation of Multiple Sclerosis

🇨🇦 MCCQE1,2 | #Case_161
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An African American patient presented with yellow discoloration of sclera, dark urine, and unusually light stool of a week duration. Physical examination confirmed the diagnosis of jaundice. The rest of physical examination was normal. Urine analysis showed bilirubinuria and a set of other lab investigations was ordered. Which of the following lab findings would
support your presumptive type of jaundiced in this patient?

❤High reticulocyte count
💛High serum alkaline phosphatase
💚Low serum albumin
💙Increased red cell fragility
💜Positive sickling test

🇨🇦 MCCQE1,2 | #Case_161 | #answer
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✅ B

🔎 Explanation

Jaundice with dark urine (due to bilirubinuria) and pale stool should prompt one to strongly suspect the diagnosis of obstructive jaundice which is typically associated with high serum levels of alkaline phosphatase (choice B). Conjugated bilirubin, which predominates in obstructive jaundice, is the form of bilirubin that can be filtered in the kidney and appears in urine. Also, metabolites of bilirubin are partly responsible for giving stool its normal color. In obstructive jaundice, conjugated bilirubin cannot reach the intestine but spills over in blood leading to lightening of stool color and
dark urine. In hepatocytes, alkaline phosphatase is concentrated in cell membranes near bile canaliculi and this is why its serum level increases in obstructive jaundice.

⚠ High reticulocyte count (choice A), increased red cell fragility (choice C) and positive sickling test (choice E) are incorrect choices. These findings suggest the diagnosis of hemolytic jaundice which should not be suspected from the clinical picture of our patient. In hemolytic jaundice, bilirubin is predominantly of the unconjugated form that cannot be filtered in glomeruli because it is tightly bound to albumin plasma. Urine will thus be of normal color in patients with this type of jaundice. Also, in hemolytic jaundice stool may be darker in color due to excretion of large amounts of bilirubin
degradation products in stool.

⚠ Low serum albumin (choice C) is not the correct choice because the half-life of albumin in serum is about 26 days. Its level is expected to be normal in acute liver diseases.

🔖 Key point:

Dark urine and pale stool in presence of jaundice are highly suggestive of obstructive jaundice.

🇨🇦 MCCQE1,2 | #Case_162
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An otherwise healthy 37-year-old male presents to your office with a 2-week history of redness and slight irritation in his groin. On examination a tender erythematous plaque with mild scaling is seen in his right crural fold. The area fluoresces coral-red under a Wood’s light. Which one of the following would be the most appropriate treatment at this time?

❤Amoxicillin
💛Erythromycin
💚Ketoconazole
💙Nystatin
💜Triamcinolone

🇨🇦 MCCQE1,2 | #Case_162 | #answer
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✅ B

🔎 Explanation

The characteristics of this lesion, including coral-red fluorescence under a Wood’s light, suggests Corynebacterium infection, which is associated with erythrasma. Tinea cruris caused by Microsporum infection fluoresces green, while intertrigo and tinea cruris caused by Epidermophyton or Trichophyton infections do not fluoresce. Erythromycin, either systemic or topical, is the treatment of choice

🇨🇦 MCCQE1,2 | #Case_163
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You are asked to see a mentally challenged 45-year-old male from a nearby group home who has groin pain. On examination you notice that he has large ears, a prominent jaw, and large symmetric testicles. These findings are consistent with:

❤A variant form of Down syndrome
💛Asperger’s syndrome
💚Klinefelter’s syndrome
💙Homocystinuria
💜Fragile X syndrome

🇨🇦 MCCQE1,2 | #Case_163 | #answer
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✅ E

🔎 Explanation

Fragile X syndrome accounts for more cases of mental retardation in males than any other genetic disorder except Down syndrome; about one in 4000-6000 males is affected. Down syndrome, Klinefelter’s syndrome, and homocystinuria do not present with the described findings. Asperger’s syndrome is a variant of autism in people of normal to high intelligence.
Patients with Klinefelter’s syndrome usually have small testicles

🇨🇦 MCCQE1,2 | #Case_164
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A 55-year-old male is brought to the emergency department with a complaint of pain in the right eye and reduced vision of about 10 minutes’ duration. His eye was injured while he was hitting a metal stake with a sledge hammer. He was not wearing safety goggles. On examination you note a subconjunctival hemorrhage completely surrounding the cornea. The iris is irregular. Which one of the following is contraindicated prior to emergency transfer to an ophthalmologist?

❤Administering an analgesic
💛Attempting tonometry
💚A visual acuity test
💙Use of an eye shield
💜Administering an antiemetic

🇨🇦 MCCQE1,2 | #Case_164 | #answer
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✅ B

🔎 Explanation

The injury and findings described raise the possibility of globe rupture due to a fragment of steel penetrating through the cornea and pupil and into the globe. Relief of pain with an analgesic (choice A) is appropriate before transfer. Because of a risk of extruding intraocular fluid, tonometry (choice B) should not be attempted if globe rupture is suspected. A rapid assessment of gross visual acuity (e.g., counting fingers, seeing light versus dark) (choice C) may be performed. An eye shield (choice D) should be placed over the affected eye to avoid putting pressure on the eye during transport to the ophthalmologist. Because the Valsalva effect from vomiting may lead to extrusion of intraocular contents, an antiemetic (choice E) would be appropriate before transfer as well

🇨🇦 MCCQE1,2 | #Case_165
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Cardiogenic shock is a major, and frequently fatal, complication of a variety of acute and chronic disorders that impair the ability of the heart to maintain adequate tissue perfusion. These patients demonstrate clinical signs of low cardiac output, with adequate intravascular volume. Which of the following is usually found on physical examination?

❤Normal capillary refill
💛Normal peripheral pulses
💚Bradycardia
💙Narrow pulse pressure
💜High urine output

🇨🇦 MCCQE1,2 | #Case_165 | #answer
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✅ D

🔎 Explanation

Cardiogenic shock characterized by primary myocardial dysfunction causes the heart to be unable to maintain adequate cardiac output. It is a medical emergency. These patients demonstrate clinical signs of low cardiac output, with adequate intravascular volume. The patients have cool and clammy extremities, poor capillary refill, tachycardia, narrow pulse pressure (choice D), and low urine output. Peripheral pulses are rapid and faint and may be irregular if arrhythmias are present.

⚠ Normal capillary refill (choice A) is incorrect. Patients in shock usually appear ashen or cyanotic and have cool skin and mottled extremities.

⚠ Normal peripheral pulses (choice B) is incorrect. Peripheral pulses are rapid and faint and may be irregular if arrhythmias are present.

⚠ Bradycardia (choice C) is incorrect. The pulse pressure may be low, and patients are usually tachycardic.

⚠ High urine output (choice E) is incorrect. These patients show signs of hypoperfusion, such as altered mental status and decreased urine output.

🇨🇦 MCCQE1,2 | #Case_166
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A 2-year-old boy is brought to the office by his father because of a 3-month history of decreased activity, poor appetite, sporadic vomiting, clumsiness and speech regression. Since his birth his family has lived in an old area of the city where there is demolition of old buildings. Examination of a peripheral blood smear is likely to show which of the following?

❤Basophilic stippling of erythrocytes
💛Degranulation of eosinophils
💚Diminished numbers of platelets
💙Howell-Jolly bodies
💜Macrocytic erythrocytes

🇨🇦 MCCQE1,2 | #Case_166 | #answer
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✅ A

🔎 Explanation

This child suffers from lead poisoning. Prior to the 1970s, lead was used in paint, gasoline, water pipes, and many other products. During the demolition of older structures, lead is released and can become ingested by humans, primarily children. Exposure to excessive levels of lead can cause brain damage; affect a child’s growth; damage kidneys; impair hearing; cause vomiting, headaches, and appetite loss; and cause learning and behavioral problems. Lead eventually becomes associated with mitochondria in red blood cells and appears as basophilic granules via H & E staining. This is a form of sideroblastic anemia.

🇨🇦 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.