MCCQE Medical Council of Canada Exam Lab Questions

Elevated hemoglobin in the absence of polycythemia vera can be due to secondary causes such as chronic hypoxia. Central sleep apnea, often associated with diabetes or neurologic conditions, leads to intermittent hypoxia and compensatory erythropoiesis.

Toronto Notes 2023 – Hematology and Respiratory Medicine, “Polycythemia” Section:

“Secondary erythrocytosis may result from hypoxic conditions including sleep apnea, COPD, or high altitude. Assess for sleep-disordered breathing in patients with elevated hemoglobin and no myeloproliferative features.”

MCCQE1 Objectives (Internal Medicine > 76-7: Hematologic Abnormalities):

“Candidates must investigate secondary causes of elevated hemoglobin, including hypoxia-related conditions.”

Hypertension (A), hypothyroidism (C), and cirrhosis (D) do not cause polycythemia. Alcohol (B) typically causes macrocytosis and anemia.

Comprehensive and Detailed Explanation:

Pulsatile tinnitus synchronous with the pulse may be vascular in origin. The association with headaches and elevated BMI (a risk factor for idiopathic intracranial hypertension, IIH) warrants neuroimaging to assess for cerebral venous sinus thrombosis, vascular malformations, or raised intracranial pressure.

Toronto Notes 2023 – Neurology / ENT:

“Pulsatile tinnitus requires investigation for vascular causes including idiopathic intracranial hypertension. MRI or MRV is the next step.”

MCCQE1 Objectives (Neurology > 35-1: Headache and Tinnitus):

“Candidates must investigate pulsatile tinnitus with neuroimaging when vascular causes are suspected.”

Audiogram (A) is for hearing loss. EEG (C) is not useful for tinnitus. CRP (D) is irrelevant.

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The most important factor in determining the surveillance interval in Barrett esophagus is the presence and grade of dysplasia (e.g., none, low-grade, high-grade). High-grade dysplasia requires more frequent monitoring or intervention due to the risk of progression to esophageal adenocarcinoma.

Toronto Notes 2023 – Gastroenterology, Barrett Esophagus:

“Surveillance intervals depend on histologic findings. No dysplasia: q3–5 years; low-grade: q6–12 months; high-grade: consider endoscopic resection or ablation.”

MCCQE1 Objectives – Internal Medicine > Gastroenterology:

“Candidates must identify the risk of progression in Barrett esophagus and apply appropriate surveillance strategies based on dysplasia.”

Length of the segment (A) may influence risk but not surveillance frequency alone. Other options (B, C, E) are less determinative.

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A varicocele is a dilatation of the pampiniform plexus that presents with a “bag of worms” appearance, worsens with standing, and improves when lying down. It is most common on the left side due to anatomical drainage differences.

Toronto Notes 2023 – Urology, Scrotal Disorders:

“Varicoceles often present with a dull, aching pain and scrotal swelling that worsens when upright and disappears when supine.”

MCCQE1 Objectives – Internal Medicine > Urology:

“Candidates must recognize and diagnose varicocele by physical exam findings and typical symptom history.”

Cryptorchidism (A) refers to undescended testes. Torsion (B) presents acutely with severe pain. Hydrocele (C) transilluminates and is not posture-dependent. "Spermatocyte" (D) is not a clinical diagnosis.

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