NAC OSCE Clinical Reasoning 2

Question 1

A patient with known type 2 diabetes presents with confusion, rapid breathing, and fruity breath odour. Blood glucose is 28 mmol/L. What is the MOST likely diagnosis?

Accepted Answer

Diabetic ketoacidosis (DKA) — characterized by hyperglycemia, metabolic acidosis, and ketonemia/ketonuria

Answer

Hypoglycemia

Answer

Hyperglycemic hyperosmolar state (HHS)

Answer

Alcohol intoxication

Question 2

A 60-year-old man presents with progressive dysphagia to solids more than liquids over 3 months, associated with weight loss. What is the MOST concerning diagnosis?

Accepted Answer

Esophageal carcinoma — progressive dysphagia to solids with weight loss in an older patient requires urgent endoscopy

Answer

Gastroesophageal reflux disease

Answer

Achalasia

Answer

Globus pharyngeus

Question 3

What is 'anchoring bias' in clinical reasoning and how can it lead to diagnostic error?

Accepted Answer

The tendency to focus on the first piece of information or initial diagnosis encountered and fail to adjust the diagnosis adequately when new contradictory information emerges

Answer

The tendency to order too many tests

Answer

The tendency to always agree with the patient's self-diagnosis

Answer

The tendency to refer every patient to a specialist

Question 4

A 35-year-old woman presents with a butterfly-shaped facial rash, joint pain, fatigue, and positive ANA. What condition should be strongly suspected?

Accepted Answer

Systemic lupus erythematosus (SLE) — the malar rash, arthralgia, fatigue, and positive ANA are classic features

Answer

Rosacea

Answer

Contact dermatitis

Answer

Rheumatoid arthritis

Question 5

A patient with known atrial fibrillation presents with sudden severe abdominal pain but a relatively benign abdominal examination ('pain out of proportion to exam'). What is the MOST likely diagnosis?

Accepted Answer

Acute mesenteric ischemia — embolic occlusion of the mesenteric artery, which is a surgical emergency

Answer

Peptic ulcer disease

Answer

Functional abdominal pain

Answer

Acute pancreatitis

Question 6

What are the Canadian Task Force on Preventive Health Care's recommendations for colorectal cancer screening in average-risk individuals?

Accepted Answer

Screening with fecal immunochemical test (FIT) every 2 years or flexible sigmoidoscopy every 10 years for adults aged 50-74

Answer

No screening is recommended

Answer

Colonoscopy every year starting at age 40

Answer

Screening only for those with a family history