Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_282 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 27-year-old male is brought to the emergency department after a car accident. He had a head on collision with another car and hit his chest on the steering wheel. On physical examination the patient’s vital signs are temperature 37.4°C, blood pressure 105/65 mmHg, pulse is 110 bpm, and respirations are 35/min. On observation of the patient’s chest wall, the chest moves inward on inspiration and outward on expiration. Auscultation reveals decreased breath sounds on the left side. What is the most likely diagnosis? a) Cardiac tamponade b) Ruptured diaphragm c) Tension pneumothorax d) Tracheal rupture e) Flail chest

🇨🇦 MCCQE1,2 | #Case_281 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation According to a recent Cochrane review, routine preoperative testing prior to cataract surgery does not decrease intraoperative or postoperative complications. The CMA recommends against routine preoperative testing in asymptomatic patients undergoing low-risk procedures, since the cardiac risk associated with such procedures is less than 1%.

🇨🇦 MCCQE1,2 | #Case_281 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 72-year-old female sees you for preoperative evaluation prior to cataract surgery. Her history and physical examination are unremarkable, and she has no medical problems other than bilateral cataracts. Which one of the following is recommended prior to surgery in this patient? a) An EKG only b) An EKG and chest radiography c) A CBC only d) A CBC and serum electrolytes e) No testing

🇨🇦 MCCQE1,2 | #Case_280 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation This patient is presenting with some non-specific constitutional symptoms that are characteristic of cancer such as unintentional weight loss and fatigue. She also complains of jaundice, which is most likely to be the cause of her unbearable pruritus. Given the Curvoisier’s sign found on physical examination (palpable but non-tender gallbladder) along with the symptoms described, her most likely diagnosis is pancreatic cancer. Pancreatic cancer is the 4th in cancer mortality. Family history and smoking history are the most common risk factors. The head of the pancreas is the location most likely to be affected with 2/3 of pancreatic cancers found in the head of the pancreas. Migratory thrombophlebitis (choice D) also known as Trousseau’s sign of malignancy is a common non-malignant manifestation of pancreatic cancer. ⚠ Muscle weakness of legs (choiceA) may be seen in Lambert-Eaton Myasthenic syndrome which is a paraneoplastic syndrome of small cell lung cancer. ⚠ Krukenberg ovarian tumor (choiceB) are metastatic disease of gastrointestinal tumors, especially gastric adenocarcinoma. ⚠ Elevated alpha-fetoprotein (choiceC) is seen in primary liver cancer. ⚠ Porcelain gallbladder history (choiceE) is associated with gallbladder cancer. It is a rare tumor and is more likely to present with a steady right upper quadrant pain. 🔖 Key point: Pancreatic cancer often presents with painless jaundice, unintentional weight loss, and fatigue. It is associated with Courvoisier's sign, Trousseau's sign, migratory thrombophlebitis.

🇨🇦 MCCQE1,2 | #Case_280 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 58-year-old female presents with complaints of weight loss, fatigue, and the yellow skin, that has been progressively changing colour (more yellow) in the last few weeks. She has had an 8kg unintentional weight loss. She also says that she has felt a need to scratch all over the body because of a constant itchy feeling. She denies abdominal pain, back pain, or abdominal fullness. She is not on any special diet. She has smoked 1 pack per day for the last 30 years. Physical examination reveals a palpable but non-tender gallbladder. Which of the following is most likely to be associated with this patient’s disease? a) Muscle weakness of legs b) Krukenberg ovarian tumor c) Elevated alpha-fetoprotein d) Migratory thrombophlebitis e) Porcelain gallbladder history

🇨🇦 MCCQE1,2 | #Case_279 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Fluid resusciation is a crucial part in the management of burn victims. The minimum amount of fluid to be administered in the first 24 hours is determined by the Parkland formula: Minimum fluid = 4ml x weight (kg) x percent of body surface area burned Half of the volume is administered in the first 8 hours, and the other half is administered over the following 16 hours. The percent of body surface area (BSA) burned can be estimated using the 'rule of nines' (image below). Lactated ringer's solution (LR) is the preferred fluid used in burn victim resuscitation because the sodium content and pH are closer to physiologic levels than normal saline. In addition, the lactate would be advantageous in its capacity to buffer the metabolic acidosis present in burn victims. Applying these rules, we see that the patient has burns over 36% of his body, thus 11520ml or 11.5L (choice C) is the minimum amount of fluid required for this patient in the first 24 hours. ⚠ 8.7 L (choice A) is incorrect. This corresponds to a burned BSA of 27%. ⚠ 10 L (choice B) is incorrect. This corresponds to a burned BSA of 31.5%. ⚠ 13 L (choice D) is incorrect. This corresponds to a burned BSA of 40.5%. ⚠ 14.5 L (choice E) is incorrect. This corresponds to a burned BSA of 45%. 🔖 Key point: The Parkland burn formula is used to determine the minimum amount of fluid required for the resuscitation of burn victims in the first 24 hours. Fluid required = 4ml * weight in kg * percent of BSA burned, with half that amount being given over the first 8 hours, and the other half given over the following 16 hours.

🇨🇦 MCCQE1,2 | #Case_279 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 32-year-old male presents to the ED having been rescued from a burning building. He is moaning in pain, and unable to answer any questions. The patient's blood pressure is 105/75 mmHg, heart rate is 110 bpm, respiratory rate 20 bpm, and co-oximetry is within normal limits. He is 1.8m, and weighs 80kg. Burns are noted on the entire anterior and posterior surfaces of his right arm, and the anterior of his right leg, chest, and abdomen. Two large bore IV lines are started, and fluids are about to be administered. What is the estimated initial minimum amount of resuscitation fluid to be administered to this patient over the next 24 hours? a) 8.7 L of lactated ringer's solution; half given over first 8 hours, half given over the following 16 hours. b) 10 L of lactated ringer's solution; half given over first 8 hours, half given over the following 16 hours. c) 11.5 L of lactated ringer's solution; half given over first 8 hours, half given over the following 16 hours. d) 13 L of lactated ringer's solution; half given over first 8 hours, half given over the following 16 hours. e) 14.5 L of lactated ringer's solution; half given over first 8 hours, half given over the following 16 hours.

🇨🇦 MCCQE1,2 | #Case_278 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation This patient suffers from postpartum urinary retention (PUR). PUR is often defined as a post-void bladder residual of at least 150 cc that is present 6 hours or more after delivery. This condition is more likely to occur in patients who are primiparous, have a prolonged first or second stage of labor, have instrumented vaginal deliveries, or require a cesarean section for failure to progress. The question of whether epidural anesthesia promotes the condition is still debated. Most cases of PUR will resolve 2-6 days after delivery, but some can take up to several weeks. The use of intermittent self-catheterization or a transurethral catheter is recommended until the patient’s ability to spontaneously micturate returns. Imaging studies and referrals to a specialist are rarely necessary, and no medication has been proven helpful.

🇨🇦 MCCQE1,2 | #Case_278 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 32-year-old primipara is ready to be discharged after a full-term vaginal delivery that was complicated by a prolonged second stage of labor. She required a second-degree posterior vaginal repair, but had no periurethral trauma. A transurethral catheter was removed a few hours after delivery, but 48 hours later she complained of abdominal pain and a persistent need to urinate. The catheter was replaced and yielded approximately 2000 cc of straw-colored urine. Urinary symptoms quickly resolved, but the patient continues to be unable to void on her own. A perineal examination is normal, as is a urinalysis. Which one of the following would be the most appropriate management at this time? a) Oxybutynin (Ditropan), 10 mg daily b) Prednisone, starting with 60 mg/day and tapering quickly over 7 days c) Urgent vaginal ultrasonography d) Urology consultation for cystoscopy e) Discharge with a catheter in place and close follow-up

🇨🇦 MCCQE1,2 | #Case_278 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation The combination of hematuria and hemoptysis should always raise the possibility of Goodpasture syndrome. Antiglomerular basement membrane antibodies are pathognomonic for this diagnosis. ⚠ Anti-mitochondrial antibodies (choice B) are found in patients with primary biliary cirrhosis. ⚠ The anti-neutrophilic cytoplasmic antibodies (choice C) are found in patients with Wegener granulomatosis. Wegener granulomatosis may also present with pulmonary and renal involvement but will have associated upper respiratory tract findings, e.g, sinusitis and sinus abscesses. ⚠ Anti-parietal cell antibodies (choice D) are found in patients with the autoimmune disease known as pernicious anemia. ⚠ Anti-smooth muscle antibodies (choice E) are found in patients with autoimmune hepatitis.

🇨🇦 MCCQE1,2 | #Case_278 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 41-year-old man presents to the clinic complaining of a chronic cough over the past 4 months, which has now been accompanied by hemoptysis. His lungs have diffuse bilateral rales. Laboratory findings reveal a sodium of 142 mEq/L, a potassium of 4.3 mEq/L, a chloride of 110 mEq/L, a bicarbonate of 24 mEq/L, a BUN of 39 mg/dL, and a creatinine of 2.9 mg/dL. Urinalysis reveals microscopic hematuria and 4+ proteinuria. Which of the following serologic blood tests would most help confirm the suspected diagnosis? a) Anti-glomerular basement membrane antibodies b) Anti-mitochondrial antibodies c) Anti-neutrophilic antibodies d) Anti-parietal cell antibodies e) Anti-smooth muscle antibodies

🇨🇦 MCCQE1,2 | #Case_277 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation This child presents with nocturnal enuresis at the age of 8 after having achieved control over micturition for 4 years. His condition is considered secondary enuresis, as this is defined as enuresis occurring 6 months after a child had been continent for at least 6 months. Normally 98% of children achieve daytime continence by the age of 3 while 80% achieve nocturnal continence by this age. By approximately age 4 years, all children with normal bladder function should have acquired this ability.When evaluating a child most likely to have secondary enuresis physicians should be alert for symptoms associated with diabetes mellitus, diabetes insipidus, cystitis, overactive bladder or dysfunctional voiding, sleep disordered breathing, constipation, urethral obstruction, and major motor seizure. Psychological problems are also possible causes of secondary enuresis. The best initial study for screening this patient is urinalysis (choice A). Cystitis would present with white blood cells and bacteria on urinalysis, while urethral obstruction may be associated with red blood cells. The presence of glucose would suggest diabetes mellitus, while a specific gravity greater than 1.020 would rule out diabetes insipidus. ⚠ Observation for 2 weeks (choice B) is incorrect. This child has been observed for the last 3 weeks and the best next step is to explore possible causes of enuresis. ⚠ Desmopressin (choice C) is considered in children with primary enuresis by the age of 7. While it may help with enuresis symptoms, it is not appropriate to start this medication before important investigations are completed. ⚠ Use of alarm devices (choice D) is also incorrect, as the child’s condition needs to be properly investigated first. ⚠ Kidneys, ureters, bladder X-ray (choice E) is incorrect. Despite its name, it is not typically used to investigate pathology of the kidney, ureter, and bladder. These structures are better assessed with intravenous pyelogram or CT urography. KUB is typically used to investigate gastrointestinal conditions such as a bowel obstruction and gallstones, and can detect the presence of kidney stones. 🔖 Key point: Secondary enuresis is urinary incontinence in children occurring 6 months after achieving control over micturition. It may be caused by anatomical abnormalities, urinary tract infections, hormonal disturbances, and psychological problems. The most important screening test is urinalysis

🇨🇦 MCCQE1,2 | #Case_277 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An 8-year-old male is brought to your department by his mother, because of bed wetting for the last 3 weeks. The mother reports that this occurs at night only and it seems to have been embarrassing for him. She states that it happens about five times a week and has continued even when the boy was put on fluid restriction after 6 pm for the last 10 days. He has not lost weight during this period and denies having excessive thirst. The boy had stopped bedwetting at the age 4 and since then he had never had a similar problem. The mother denies any changes in the family or stressful events and says that the boy’s nutrition is regular and he was not on any special diet. Which of the following is the initial step in management of this patient? a) Urinalysis b) Observation for 2 weeks c) Desmopressin d) Use of alarm devices e) Kidneys, ureters, bladder X-ray (KUB)

🇨🇦 MCCQE1,2 | #Case_276 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation The most dreaded acute complication for this patient would be monocular visual loss. The patient has findings suggestive of polymyalgia rheumatica with probable associated temporal arteritis. These conditions may be different manifestations of the same disease process. Shoulder and thigh pain are typical, and morning stiffness, low-grade fever, and weight loss are common. Jaw claudication and depression may be associated findings, and paralysis and stroke develop less frequently. Intracranial arteries are usually spared, but the verterbral basilar arteries may be involved. Sudden death with arteritis of the coronary arteries is extremely rare. Seizures are not characteristic. Adhesive capsulitis can develop as a secondary manifestation of any shoulder disorder that limits mobility. This tends to develop gradually rather than acutely, and can usually be avoided with appropriate therapy

🇨🇦 MCCQE1,2 | #Case_276 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An 82-year-old white female visits your office. She reports a 2-week history of shoulder stiffness that is severe in the morning, and a 3-day history of pain on the left side of the face while chewing food. She denies dental pain or sensitivity. Her family history is negative for rheumatologic disorders. Your evaluation reveals a 5-lb weight loss and evidence of mild depression. Her temperature is 38.0°C (100.4°F), she has no dental decay or carotid bruit, and her left temporal scalp is tender. Her lungs are clear to auscultation, there are no abnormal heart sounds, and her abdomen is nontender. She has no joint swelling or warmth, but experiences discomfort with shoulder and hip range of motion. Laboratory analysis reveals a hemoglobin level of 110 g/L (N 123-175), an erythrocyte sedimentation rate of 80 mm/hr (N 0 - 30), a serum glucose level of 6.7 mmol/L, and a BUN level of 8.57 mmol/L (N 2.5-8.0). Which one of the following is the greatest immediate risk for this patient? a) Monocular vision loss b) Hemiparesis c) Seizure d) Sudden death e) Adhesive capsulitis of the shoulder

🇨🇦 MCCQE1,2 | #Case_275 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation SSRIs are considered first-line treatment for premenstrual dysphoric disorder. Several randomized trials have shown that they are superior to placebo for this condition. Fluoxetine and sertraline have been studied the most. ⚠ There have been no controlled trials to support anecdotal reports of benefit from the reduction of caffeine or refined sugar. ⚠ Studies using alprazolam have shown it to be effective for premenstrual anxiety only. ⚠ Progesterone has not been proven more effective than placebo in clinical trials, and bupropion is less effective than agents that primarily boost serotonergic activity.

🇨🇦 MCCQE1,2 | #Case_275 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 27-year-old white female has a 10 year history of significant premenstrual dysphoria. Her condition has significantly worsened in the past 3 years, to the point that it is endangering her marriage of 5 year. Her symptoms are worse for the 10 days prior to her menstrual period and are gone by day 2 of her period. She has tried several measures without success, including birth control pills, various herbal preparations, and counseling at a woman’s health center. You recommend: a) Reduction of caffeine and refined sugar intake b) Alprazolam c) Bupropion d) Progesterone e) Fluoxetine

🇨🇦 MCCQE1,2 | #Case_274 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation This patient has acute necrotizing ulcerative gingivitis (ANUG, known as trench mouth). The onset is sudden and findings include tender, bleeding gums, malodorous breath, and a bad taste in the mouth. The disease is frequently associated with systemic findings such as fever, anorexia, malaise, tachycardia, cervical lymphadenopathy, and leukocytosis. Characteristic gingival lesions are seen, appearing as marginal punched-out, crater-like depressions of the interdental gingival papillae and gingival margin. They are covered with a gray pseudomembranous slough that is demarcated from the remainder of the gingival and bleeds when removed. The causative organisms are mostly anaerobic bacteria.These lesions may be related to a single tooth, a group of teeth, or the gingival throughout the mouth. Management includes removing predisposing factors such as stress, fatigue, heavy smoking, and poor nutrition that can cause tissue breakdown. Mouth rinses with warm half-strength hydrogen peroxide are useful. When fever and lymphadenopathy occur, antibiotic treatment is warranted and penicillin is the drug of choice. Tetracycline and erythromycin are good alternatives.

🇨🇦 MCCQE1,2 | #Case_274 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 16-year-old white female experiences the sudden onset of tender, bleeding gums, malodorous breath, and a bad taste in her mouth. On examination she is febrile and has cervical lymphadenopathy and tachycardia. Her mouth has marginal punched-out, crater like depression of the interdental gingival papillae and gingival margins that are covered with a gray pseudomembranous slough. The drug of choice for treating this condition is: a) Acyclovir (Zovirax) b) Penicillin c) Clotrimazole troche (Mycelex) d) Ketoconazole (Nizoral) e) Prednisone

🇨🇦 MCCQE1,2 | #Case_273 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation The cardinal signs of infectious flexor tenosynovitis include: •Tenderness along the course of the flexor sheath •Symmetric enlargement of the affected digit •Slightly flexed finger at rest •Pain along the tendon with passive extension Pain with passive extension is the earliest finding; tenderness along the tendon sheath was a late sign of infection. Severe pain and tenderness following a bite or puncture wound should suggest the presence of tenosynovitis regardless of whether it is associated with all, some, or none of the above findings. The diagnosis is made by eliciting tenderness on palpation of the tendon and sheath and by noting swelling and possibly a nodule. In later stages, triggering or snapping of the digit occurs on flexion (trigger finger)