Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_98 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 41-year-old man is seen for hematuria. He states that he has had this on two previous occasions, both in relation to an upper respiratory tract infection. On both previous occasions the urine cleared spontaneously over a period of five to seven days.At the time of the present visit he states that he has been feeling lethargic with a sore throat for the past five days. Blood pressure is 170/95, urine analysis shows specific gravity 1020, nitrites negative, +++ blood and +++ protein. Urine microscopy reveals oxalate crystals, dysmorphic red blood cells and red cell casts. The presence of dysmorphic red blood cells is indicative of: a) Urine infection b) Delay in analysis of the urine sample c) Glomerular bleeding d) Urothelial malignancy e) Urinary tract calculus

🇨🇦 MCCQE1,2 | #Case_97 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation The diastolic murmur best heard when patient leaning forward at Erb's point, located at the 3rd intercostal space on the left, is most likely to be aortic regurgitation. One of the hallmark physical findings of this valvular lesion is the presence of a wide pulse pressure (choice E) secondary to the diastolic run-off back into the ventricle. Other signs such as Quincke’s pulse or Musset’s sign may also be present. ⚠ A bifid pulse (choice A) is seen with hypertrophic cardiomyopathy and is best appreciated by palpation of the carotid artery. This bifid pulse occurs as a result of no obstruction to blood flowing out from the left heart chamber in the beginning, followed by an obstruction in the middle of systole, and finally by a lessening of the obstruction at the end of systole. ⚠ Low amplitude pulse (choice B) is seen with peripheral arteriosclerosis. ⚠ Pulsus alternans (choice C) where one pulse feels large, the next pulse feels small, is appreciated with severe congestive heart failure. ⚠ Pulsus paradoxus (choice D) is an exaggeration of a normally present fall is systolic blood pressure with inspiration. Normal decrease in systolic pressure should be 10 mm Hg or less but with pulsus paradoxus, it can be 15-20 mm Hg. This is most commonly seen with constrictive or restrictive diseases of the heart or pericardium.

🇨🇦 MCCQE1,2 | #Case_97 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 68-year-old white man comes to the office because of increasing shortness of breath on exertion for the past 2 to 3 months. He has a history of hypertension for which he takes hydrochlorothiazide. On physical examination his pulse is 80/min. There's a diastolic decrescendo murmur heard best at the 3rd intercostal space on the left with the patient sitting up and leaning forward. Further physical examination is most likely to show: a) Bifid pulse b) Low-amplitude pulse c) Pulsus alternans d) Pulsus paradoxus e) Wide pulse pressure

🇨🇦 MCCQE1,2 | #Case_96 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This patient experienced acute mountain sickness (AMS), which is the most common altitude illness. It occurs in 40%-50% of persons from low altitudes who ascend to 14,000 feet. The onset can occur within 8 to 96 hours of arrival at altitudes above 8000 feet, although the altitudes at which symptoms begin vary significantly. AMS is a clinical diagnosis, with the most common symptoms consisting of headache, poor sleep, anorexia, fatigue, nausea, and vomiting. Slow ascent is the best way to avoid AMS. Adequate hydration may be helpful. Acetazolamide and dexamethasone help prevent or mitigate the symptoms of AMS. Individuals who have had AMS in the past should probably be treated prophylactically with acetazolamide.Acetazolamide is a carbonic anhydrase inhibitor that causes a hyperchloremic metabolic acidosis through the loss of bicarbonate, sodium, and potassium in the urine. Respiration is stimulated by the acidosis, which leads to a compensatory respiratory alkalosis. Pretreatment with this agent mimics the acclimated state of acid-base balance, so that during the first day of altitude exposure, subjects taking this drug have values for pH, partial pressure of arterial carbon dioxide, and minute ventilation that are not typically observed until day 5 in control subjects.

🇨🇦 MCCQE1,2 | #Case_96 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 28-year-old male visits your office because he is planning a ski trip. You practice in a coastal area, and he plans to be at an altitude of 14,500 feet. On a previous ski trip to the same altitude he experienced symptoms of headache, poor sleep, anorexia, fatigue, nausea, and vomiting. He asks you what he can do to prevent these symptoms on his upcoming trip. Which one of the following would you recommend? a) Caffeine avoidance b) Caffeine tablets c) Furosemide (Lasix) d) Acetazolamide (Diamox) e) Fluid restriction

🇨🇦 MCCQE1,2 | #Case_95 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Anaerobic lung abscesses are most often found in a person predisposed to aspiration who complains of a productive cough associated with fever, anorexia, and weakness. Physical examination usually reveals poor dental hygiene, a fetid odor to the breath and sputum, rales, and pulmonary findings consistent with consolidation. ⚠ Patients who have sarcoidosis (choice A) usually do not have a productive cough and have bilateral physical findings. ⚠ A persistent productive cough is not a striking finding in disseminated tuberculosis, which would be suggested by miliary calcifications (choice B) on a chest film. ⚠ The clinical presentation and physical findings are not consistent with a simple mass in the right hilum (choice D) nor with a right pleural effusion (choice E).

🇨🇦 MCCQE1,2 | #Case_95 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 25-year-old white male who has a poorly controlled major seizure disorder and a 6-week history of recurrent fever, anorexia, and persistent, productive coughing visits your office. On physical examination he is noted to have a temperature of 38.3°C (101.0°F), a respiratory rate of 16/min, gingival hyperplasia, and a fetid odor to his breath. Auscultation of the lungs reveals rales in the mid-portion of the right lung posteriorly. Which one of the following is most likely to be found on a chest radiograph? a) Sarcoidosis b) Miliary calcifications c) A lung abscess d) A right hilar mass e) A right pleural effusion

🇨🇦 MCCQE1,2 | #Case_94 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation Antibiotic treatment of nursing-home patients with asymptomatic bacteriuria is not beneficial. Chronic incontinence is not improved, subsequent episodes of symptomatic urinary tract infection are not reduced, and there is no decrease in overall mortality

🇨🇦 MCCQE1,2 | #Case_94 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 90-year-old Asian female who lives in a nursing home is noted to have > 100,000 Escherichia coli on urine culture, performed because her urine “smelled strong.” She is afebrile and is asymptomatic. Which one of the following is most appropriate? a) Antibiotic treatment for 3 days b) Antibiotic treatment for 10 days c) A repeat culture and treatment if positive d) Foley catheter insertion e) No treatment

🇨🇦 MCCQE1,2 | #Case_93 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation The most likely diagnosis is cutaneous leishmaniasis, caused by an intracellular parasite transmitted by the bite of small sandflies. Lesions develop gradually, and are often misdiagnosed as folliculitis or as infected epidermal inclusion cysts, but they fail to respond to usual skin antibiotics. Hundreds of cases have been diagnosed in troops returning from Iraq, most likely due to Leishmania major.Treatment is not always required, as most lesions will resolve over several months; however, scarring is frequent. Military medical facilities and the CDC are coordinating treatment when indicated with sodium stibogluconate.

🇨🇦 MCCQE1,2 | #Case_93 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 36-year-old member of the National Guard who has just returned from Iraq consults you because of several “boils” on the back of his neck that have failed to heal over the last 6 months, despite two week-long courses of cephalexin (Keflex). You observe three 1- to 2-cm raised minimally tender lesions with central ulceration and crust formation. He denies any fever or systemic symptoms.The most likely cause of these lesions is: a) Pyogenic granuloma b) Leishmaniasis c) Atypical mycobacterial infection d) Squamous cell carcinoma e) Epidermal inclusion cysts

🇨🇦 MCCQE1,2 | #Case_92 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Adnexal masses in women under 45 years of age are benign in 80%-85% of cases. The specific findings of this case also strongly suggest a benign etiology, namely a thin-walled, simple cyst, a lesion that is less than 8 cm in size, and a patient of relatively young age. No aggressive means are indicated in these situations unless there are significant clinical symptoms such as pain, abdominal pressure, urinary symptoms, or gastrointestinal symptoms. Most experts currently recommend a conservative approach with repeat ultrasonography in at least 2 months, during which time the vast majority of benign cysts resolve spontaneously

🇨🇦 MCCQE1,2 | #Case_92 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 During a routine physical examination of a 35-year-old Asian female, you note a right adnexal fullness. She has had no symptoms of pain or bloating and has been menstruating normally. Her menses occur approximately every 30 days and her next period is expected to occur in 1 week. Pelvic ultrasonography reveals a thin-walled simple cyst 5 cm in diameter. No other abnormalities are seen in the pelvic structures. Which one of the following is the best course of management for this condition? a) Reassurance only b) Checking for any increase in adnexal fullness at her next annual physical examination c) Repeat ultrasonography in 2-3 months to confirm resolution of the cyst d) Referral for ultrasound guided aspiration of the cyst e) Referral for laparoscopic removal of the cyst

🇨🇦 MCCQE1,2 | #Case_91 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation This patient’s symptoms are typical of spinal stenosis, as they are present when he is standing and relieved by sitting. He has already failed a trial of NSAIDs and bracing. Spinal decompression surgery is now indicated. Epidural corticosteroid injection might be helpful, but not trigger-point injections. Oral corticosteroids would be helpful if he had a herniated disc. Sympathectomy and bypass surgery are treatments for vascular occlusion.

🇨🇦 MCCQE1,2 | #Case_91 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 72 year old white male with known coronary artery disease complains of pain in his back and legs which is increased by standing and walking and relieved by sitting. On examination, deep tendon reflexes in his legs are 0 to 1+ bilaterally. He has mild muscle weakness of his quadriceps and 1+ pedal pulses. He is taking ibuprofen, 800 mg three times a day, and using a back brace without much relief. Which one of the following would be most likely to relieve his symptoms? a) Sympathectomy b) Aortofemoral bypass c) Trigger-point corticosteroid injections d) Posterior spinal decompression surgery e) Systemic oral corticosteroids

🇨🇦 MCCQE1,2 | #Case_90 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation As of 2014, colorectal cancer is the second most common cause of cancer death in males, and third most common cause of cancer death in females. Screening can take the form of a screening colonoscopy, flexible sigmoidoscopy, fecal occult blood testing, barium enema, and CT colonography ("virtual colonoscopy"). The most preferred test is the colonoscopy for its accuracy, and because it allows direct visualization and biopsy of lesions. Screening colonoscopy guidelines include the following: - General population: colonoscopy every 10 years - Family history of colon cancer: colonoscopy starting at the age of 40, or 10 years before incidence in the family member, whichever comes first - Personal history of colon cancer: colonoscopy at 1, 3, and 5 years after resection of the cancer - Personal history of adenomatous polyps: colonoscopy every 3-5 years after - Ulcerative colitis: colonoscopy every 1-2 years starting 8-10 years after colonic involvement - Hereditary non-poliposis colorectal cancer (choice D): colonoscopy evey 1-2 years starting at the age of 25 - Familial Adenomatous Polyposis Coli: sigmoidoscopies starting at 10-12 years with colectomy when polyps are found. ⚠ A 47-year-old hypertensive female with no personal or family history of colon cancer (choice A) is incorrect. She does not need screening for another three years. Hypertension does not alter the screening schedule. ⚠ A 30-year-old diabetic male with a family history of colon cancer in his father at the age of 45 (choice B) does not need screening until age 35 (10 years before onset in family member). ⚠ A 40-year-old male with Peutz-Jeghers syndrome and no family history of cancer and negative colonoscopy 1 year ago (choice C) would not require the colon cancer screening. Surveillance for gastric and small-bowel polyposis should begin at age 8-10 years and continue at 2-year intervals. ⚠ A 60-year-old male with a history of colon cancer resection 2 years ago and a colonoscopy 1 year ago (choice E) does not need a colonoscopy for another two years. Patients with previous colon cancer resection receive screening colonoscopy at 1, 3, and 5 years after resection. 🔖 Key point: Colon cancer is an important cause of morbidity and mortality. Screening exists to detect and treat it early. Screening starts at the age of 50 in the general population, and at 25 in patients with Hereditary non-poliposis colorectal cancer (HNPCC).

🇨🇦 MCCQE1,2 | #Case_90 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A family physician has a short break between seeing patients in her busy clinic. Looking over her survey, she wants to identify which patients need to be referred for screening colonoscopy. Which of the following patients should be screened for colon cancer? a) A 47-year-old hypertensive female with no personal or family history of colon cancer b) A 30-year-old diabetic male with a family history of colon cancer in his father at the age of 45 c) A 40-year-old male with Peutz-Jeghers syndrome with negative family history of cancer and negative colonoscopy 1 year ago d) A 25-year-old male with a personal and family hereditary non-polyposis colorectal cancer e) A 60-year-old male with a history of colon cancer resection 2 years ago and a colonoscopy 1 year ago

🇨🇦 MCCQE1,2 | #Case_89 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation The patient is suffering an inferior wall myocardial infarction, which is characterized by elevation of the ST segment of the leads II, III and aVF. The differential regarding the arteries that can be involved in such event is between the Right Coronary Artery, and the Left Circumflex Artery. The definite differential is, of course, defined when a coronary angiography is performed. However, the ECG can also be used to estimate which artery is involved in an inferior wall Myocardial Infarction. When the ST segment elevation in lead II is equal to the one present in lead III, combined with ST segment depression in leads V1 to V3 or ST elevation in leads I and aVL, it is most likely that the left circumflex coronary artery is occluded. This finding (ST segment depression in precordial leads) is highly sensitive, but not specific of left circumflex coronary artery occlusion; however, the absence of ST depression in precordial leads is of high negative predictive value for excluding the left circumflex artery as the affected artery. ⚠ When the findings in the ECG are ST segment elevation in lead III that exceeds the ST elevation in lead II, as well as depression in ST in I and aVL, the most likely artery to be occluded is the right coronary artery (70% sensitivity and 72% specificity) (choice A and B). When a patient has an inferior MI with right-sided ST elevation in leads V1 and V4R, that is indicative of a right ventricle infarction, in which case, the most likely affected artery is the right coronary artery. ⚠ An occlusion of the Left Anterior Descendant Coronary Artery (choice D) (causing an anterior infarction), ST elevation or Q waves in one or more of the precordial leads (V1-V6) and leads I and aVL is most likely to be the ECG finding. ⚠ ST elevation of aVR equal or greater to that of V1 in an anterior wall is helpful to distinguish between Left Main Coronary Artery (choice E) occlusion and Left Anterior Descendant Coronary Artery Occlusion. 🔖 Key point: It is important to consider the whole picture when evaluating an ECG of a patient with a suspected Myocardial Infarction. ST segment changes (depression) in the precordial leads helps to differentiate which artery is affected, pointing towards occlusion of the left circumflex artery. When such changes are absent it is most likely that the affected artery is the right coronary artery, rather than the left circumflex artery.

🇨🇦 MCCQE1,2 | #Case_89 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 68-year-old man is brought to the Emergency Department due to intense chest pain, accompanied with diaphoresis and vomiting, that started 30 minutes ago. He has a history of well controlled diabetes mellitus type 2 with metformin, and hypertension of difficult control for the last 10 years, as well as a history of heavy smoking.He is conscious, and in severe distress. His vital signs reveal a pulse of 80/min, BP 90/60 mmHg and his respiration of 21/min. An ECG is performed revealing ST segment elevations in II, III and aVF, noting that the ST segment elevation in III equal to the one in II, as well as ST depression in V1-V3. Troponin is increased. You give the diagnosis of inferior myocardial infarction. Considering this information, where would the occlusion most likely be found? a) Proximal right coronary artery b) Distal right coronary artery c) Left circumflex artery d) Left anterior descendant artery e) Left main coronary artery

🇨🇦 MCCQE1,2 | #Case_88 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation Key features include the central location, history of smoking (small cell carcinomas are closely associated with a history of smoking), and the presence of a paraneoplastic syndrome, in this case Cushing’s syndrome from tumor elaboration of ACTH outside hypothalamic-pituitary-adrenal axis regulation. The syndrome of inappropriate ADH secretion and Eaton-Lambert syndrome are other paraneoplastic syndromes associated with small cell lung carcinoma. Metastases are commonly present at the time of diagnosis. Favored sites are brain, liver, and bone. ⚠Adenocarcinoma is incorrect because it typically presents peripherally and is not associated with Cushing’s syndrome.(choice A) ⚠Cancer metastatic to the lung is incorrect. In this instance, there is a single lesion in the lung and multiple lesions in the liver. The site of multiple solid masses is more likely the destination of the metastasis, while the solitary nodule in the lung is likely to be the primary.(choice B) ⚠Large cell carcinoma is incorrect because they typically present on the periphery, are not associated with Cushing’s syndrome, and are the least frequent type of lung cancer.(choice C) ⚠Squamous cell carcinoma is incorrect. Although squamous cell lung carcinoma presents centrally and is clearly linked to smoking, a paraneoplastic syndrome marked by excess ACTH would not be expected. Excess parathyroid hormone and resultant hypercalcemia, however, is associated with squamous cell cancers.(choice E)