Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_173 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation In elderly patients, detrusor instability is the most common cause of urinary incontinence in both men and women. Incontinence may actually become worse after surgical relief of obstructive prostatic hypertrophy. Infection is unlikely as the cause of persistent incontinence in this patient in the absence of fever or symptoms of urinary tract infection. Overflow is unlikely in the absence of residual urine. Impaction is a relatively rare cause of urinary incontinence, and associated findings would be present on rectal examination. Normalization of the urinary stream and the absence of residual urine reduce the likelihood of recurrent obstruction. The prostate would be expected to remain enlarged on rectal examination after transurethral resection of the prostate (TURP).

🇨🇦 MCCQE1,2 | #Case_173 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 77-year-old white male complains of urinary incontinence of more than one year’s duration. The incontinence occurs with sudden urgency. No association with coughing or positional change has been noted. There is no history of fever or dysuria. One year ago he underwent transurethral resection of the prostate (TURP) for benign prostatic hypertrophy and says his urinary stream has improved. Rectal examination reveals a smoothly enlarged prostate without nodularity, and normal sphincter tone. No residual urine is found post-void catherterization. Which one of the following is the most likely cause of this patient’s incontinence? ❤Detrusor instability 💛Urinary tract infection 💚Overflow 💙Fecal impaction 💜Recurrent bladder outlet obstruction

🇨🇦 MCCQE1,2 | #Case_172 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation This woman presents with a history suggestive of achalasia. This is indicated by the dysphagia of both solids and liquids occurring simultaneously, regurgitation, weight loss, and her past history of Chagas disease. Achalasia is an esophageal motility disorder characterized by the absence of esophageal peristalsis and impaired relaxation of the lower esophageal sphincter in response to swallowing. The vast majority is of unknown etiology while a small percentage can be from Chagas disease, gastric carcinoma, and lymphoma. The most accurate diagnostic test to confirm achalasia is esophageal manometry (choice D), which shows increased lower esophageal resting pressure. ⚠ Esophagogastroduodenoscopy (choice A) is done when cancer red-flag symptoms such as anemia, heme-positive stools, weight loss, symptoms longer than 6 months in a patient >60 years old are present. ⚠ Chest plain radiography (choice B) may show an air-fluid level in the dilated esophagus, but it is not accurate enough to confirm the diagnosis. ⚠ Barium esophagography (barium swallow) (choice C) is a very accurate test and shows dilation of the esophagus, which narrows into the classic “bird’s beak” at the distal end; however, this is not the most accurate test available. Choose barium swallow if esophageal manometry is not in the answer choices. ⚠ Response to proton pump inhibitors (choice E) is a common way to confirm gastroesophageal reflux disease (GERD). 🔖 Key Point: Dysphagia of both solids and liquids simultaneously accompanied by regurgitation and weight loss in a patient with a history of Chagas disease suggests achalasia. Esophageal manometry is the most accurate diagnostic test while barium esophagography is the second best test to accurately diagnose this condition.

🇨🇦 MCCQE1,2 | #Case_172 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 34-year-old female of Brazilian-Canadian origin, who works as an accountant, comes to the clinic complaining of difficulty swallowing both solid foods and liquids. It started 2 months ago but recently she feels that it is getting worse. She has noticed a 5 kg weight loss in the past 2 months. She also experiences heartburn and sometimes feels regurgitation of foods. Her past medical history is only remarkable for Chagas disease 20 years ago while she was a teenager living in Brazil. She denies smoking or drinking. What is the most accurate diagnostic method to confirm the diagnosis? ❤Esophagogastroduodenoscopy (EGD) 💛Chest plain radiography 💚Barium esophagography 💙Esophageal manometry 💜Response to proton pump inhibitors

🇨🇦 MCCQE1,2 | #Case_171 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation This patient presents with stridor that worsens on insepiration and when he is in the supine position, which is typical of laryngomalacia (choice E). It is a congenital abnormality of the laryngeal cartilage, the most common cause of congenital stridor and is the most common congenital lesion of the larynx. It is a dynamic lesion resulting in collapse of the supraglottic structures during inspiration leading to airway obstruction. The epiglottis is curled on itself to form an omega-shaped epiglottis. 90% of cases heal by themselves by the age of 2 without any treatment. Diagnosis is best confirmed with laryngoscopy or bronchoscopy. In cases with the typical stridor that worsens when the child lies down, it is reasonable to make the diagnosis based on clinical presentation. ⚠ Airway foreign body (choice A) is seen in aspiration of objects by toddlers and pre school children. The presentation is acute with a child suddenly coughing or choking. New abnormal airway sounds are heard and are often unilateral. Stridor is heard during both phases of respiration, inspiration and expiration. ⚠ Choanal atresia (choice B) is a supralaryngeal cause of stridor with the back of the nasal passage blocked by abnormal bony or membranous tissue due to failed recanalization of the nasal fossae during fetal development. Bilateral choanal atresia is more serious than unilateral choanal atresia and crying alleviates respiratory distress. ⚠ Laryngotracheobronchitis (choice C) or Croup as it is commonly called, manifests as hoarseness, a seal-like barking cough, and a variable degree of respiratory distress.The most common cause of Croup is parainfluenza infection. ⚠ Subglottic stenosis (choice D) can be congenital or acquired. Stridor of subglottic stenosis is typically biphasic. Acquired forms usually arise from endotracheal intubation. 🔖 Key point: Laryngomalacia is characterized by an immature cartilage that leads to collapse of the supraglottic structures during inspiration, and results in airway obstruction. Stridor that worsens when the child lies supine is typical and can be used to make a clinical diagnosis. The diagnosis is confirmed with bronchoscopy and laryngoscopy.

🇨🇦 MCCQE1,2 | #Case_171 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 2-month-old male is brought in by his mother who has noted unusual sounds while the baby is breathing. She states that it started about weeks ago, but yesterday, it sounded like it was getting worse. The breathing noise is usually heard when the baby is lying on his back or crying, and it improves when she holds the baby on her shoulder. She also noticed that the sounds are worse when the baby is breathing in but they get better on exhalation. The pregnancy and delivery were uneventful and the baby had been growing well since birth. On physical examination you note stridor that increases on inspiration heard best just above the sternal notch. Which of the following is the most likely diagnosis? ❤Airway foreign body 💛Choanal atresia 💚Laryngotracheobronchitis 💙Subglottic stenosis 💜Laryngomalacia

🇨🇦 MCCQE1,2 | #Case_170 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation The history and physical raises the possibility of HIV infection. There is a strong suggestion of homosexuality, given that the rectal examination demonstrates multiple perianal contusions and blood oozing from the anal orifice. Furthermore, this man has generalized lymphadenopathy; his chief complaint is of pulmonary distress with an x-ray consistent with Pneumocystis carinii pneumonia (PCP). Since the patient has become increasingly short of breath and is febrile, he should be treated with intravenous therapy. Treatment of choice for PCP is Bactrim (trimethoprim-sulfamethoxazole).

🇨🇦 MCCQE1,2 | #Case_170 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 32-year-old man presents with increased shortness of breath and he has had a cough for the past week. He appears dyspneic and has a temperature of 38.3°C (101.0°F). On physical examination he has bibasilar rales and generalized lymphadenopathy. Rectal examination shows multiple perianal contusions and a small amount of blood oozing from the anal orifice. Chest x-ray film shows bilateral patchy alveolar infiltrates. The most appropriate next step is: ❤Admit him to the hospital and begin administration of trimethoprim-sulfamethoxazole, intravenously 💛Admit him to the hospital and begin administration of penicillin and gentamicin, intravenously 💚Begin administration of erythromycin, orally, and see him again the next day 💙Prescribe isoniazid and rifampin, orally 💜Recommend aspirin, fluids and rest at home

🇨🇦 MCCQE1,2 | #Case_169 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation Nonalcoholic fatty liver disease is the most likely diagnosis in this patient, but hepatitis B and C should be ruled out (choice D). The patient's alcohol consumption of less than two drinks per week makes alcoholic fatty liver disease unlikely. ⚠ A liver biopsy (choice A) would not be appropriate at this time. ⚠ Liver ultrasonography (choice B) should be considered after hepatitis B and C are ruled out. ⚠ The patient is younger than the recommended screening age for colonoscopy (choice C). ⚠ There is no rason to repeat previously repeated test results (lab error unlikely) (choice E).

🇨🇦 MCCQE1,2 | #Case_169 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An otherwise healthy 40-year-old male comes to your office for follow-up of elevated liver enzymes on an insurance examination. He is 173 cm (68 in) tall and weighs 113 kg (250 lb) (BMI 37.7 kg/m²). He says he drinks about two beers per week. Findings are normal on a physical examination, except for a slightly enlarged liver. AST and ALT levels are twice the upper limits of normal. Which one of the following would be the most appropriate next step? ❤A liver biopsy 💛Ultrasonography of the liver 💚Colonoscopy 💙Testing for viral hepatitis 💜Repeat AST and ALT levels in 3 months

🇨🇦 MCCQE1,2 | #Case_168 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ 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.

🇨🇦 MCCQE1,2 | #Case_168 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 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_167 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ 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_167 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 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_166 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ 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_166 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 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_165 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ 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_165 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 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_164 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ 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_164 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 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