🇨🇦 MCCQE1,2 | #Case_156
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A 27-year-old female complains of palpitations and heat intolerance. She had similar symptoms before being diagnosed with hyperthyroidism and treated with propylthiouracil. The propylthiouracil was discontinued 6 weeks ago by an emergency department physician because the patient developed a rash. The rash resolved and the patient did not keep a recommended follow-up appointment with you. On physical examination, the patient’s pulse is 134 beats/min and regular, her blood pressure is 136/58 mm Hg, and her temperature is 36.9°C (98.4°F). The thyroid is diffusely enlarged without nodularity. The skin is moist and a fine tremor is present. The examination is otherwise unremarkable. Which one of the following is most likely to be effective for initial symptom control?

❤Propranolol (Inderal)
💛Potassium iodide (SSKI)
💚Verapamil (Calan, Isoptin)
💙Adenosine (Adenocard)
💜Diltiazem (Cardizem)

🇨🇦 MCCQE1,2 | #Case_156 | #answer
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✅ A

🔎 Explanation

Symptoms of hyperthyroidism including palpitations, heat intolerance, tachycardia, and tremor are largely mediated by increased adrenergic activity. Propranolol is useful for treating the symptoms of mild hyperthyroidism. It is effective in decreasing tachycardia and tremor and also has a role in the treatment of thyroid storm. At high doses it blocks conversion of T4 to T3, in addition to providing beta-blockade. Antithyroid agents such as propylthiouracil are useful, but require an extended period for symptom control. Potassium iodide should not be used until antithyroid therapy with an agent such as propylthiouracil has been instituted. It is most frequently used as part of the treatment of thyroid storm. Calcium channel blockers such as diltiazem and verapamil may be useful in slowing supraventricular arrhythmias by blocking conduction at the AV node. They are not useful for the adrenergically triggered sinus tachycardia of hyperthyroidism. Adenosine has similar but transient effects on the AV node

🇨🇦 MCCQE1,2 | #Case_157
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A 54-year-old white male presents with drooping of his right eyelid for 3 weeks. On examination, he has ptosis of the right upper lid, miosis of the right pupil, and decreased sweating on the right side of his face. Extraocular muscle
movements are intact. In addition to a complete history and physical examination, which one of the following would be most appropriate at this point?

❤A chest radiograph
💛MRI of the brain and orbits
💚131 Iodine thyroid scanning
💙A fasting blood glucose level
💜An acetylcholine receptor antibody level

🇨🇦 MCCQE1,2 | #Case_157 | #answer
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✅ A

🔎 Explanation

The clinical triad of Horner’s syndrome—ipsilateral ptosis, miosis, and decreased facial sweating—suggests decreased sympathetic innervation due to involvement of the stellate ganglion, a complication of Pancoast’s superior sulcus tumors of the lung. Radiographs or MRI of the pulmonary apices and paracervical area is indicated. Horner’s syndrome may accompany intracranial pathology, such as the lateral medullary syndrome (Wallenberg’s syndrome), but is associated with multiple other neurologic symptoms, so MRI of the brain is not indicated at this point. The acetylcholine receptor antibody level is a test for myasthenia gravis, which can also present with ptosis, but not with full-blown Horner’s syndrome. Diabetes mellitus and thyroid disease do not commonly present with Horner’s syndrome.

🇨🇦 MCCQE1,2 | #Case_158
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A 38 year old male is admitted to the hospital after being found lying on the floor unconscious from a drug overdose. The next morning, he is alert and complains of constant pain in the anterior aspect of his left leg. On examination, you note pain with passive stretching, pain with palpation anteriorly, and a slightly decreased dorsalis pedis pulse on the left. There is no edema or erythema. Radiographs of the lower extremity are normal. Which one of the following would you do now?

❤Recommend rest, ice, and elevation, along with physical therapy
💛Begin empiric intravenous antibiotics
💚Order duplex Doppler ultrasonography of the left leg
💙Order impedance plethysmography of the left leg
💜Obtain immediate surgical consultation

🇨🇦 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