Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_233 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation At least one million Canadians suffer from urinary incontinence. In the neurologically intact individual the most common subtypes are stress incontinence, which occurs with coughing or lifting; urge incontinence, which occurs when patients sense the urge to void but are unable to inhibit leakage long enough to reach the toilet; and overflow incontinence, which occurs when the bladder cannot empty normally and becomes overdistended. The term functional incontinence is applied to those cases where lower urinary tract function is intact but other factors such as immobility and severe cognitive impairment lead to incontinence. This patient has mild urge incontinence. The first approach to this problem should be behavioral. In a mild case such as this, a cure can be expected, with success rates of 30%-90% in published studies. For more severe cases, various pharmacologic agents, including anticholinergics, are useful. Failure of these modalities should lead to urodynamic testing and consideration of surgery

🇨🇦 MCCQE1,2 | #Case_233 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 70-year-old white female complains of two episodes of urinary incontinence. On both occasions she was unable to reach a bathroom in time to prevent loss of urine. The first episode occurred when she was in her car and the second while she was in a shopping mall. She is reluctant to go out because of this problem.The most likely cause of her problem is: a) Overflow incontinence b) Stress incontinence c) Urge incontinence d) Functional incontinence

🇨🇦 MCCQE1,2 | #Case_232 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation Angina decubitus (choice D) is the correct answer. It is angina that occurs when a person is lying down (not necessarily only at night) without any apparent cause. Angina decubitus occurs because gravity redistributes fluids in the body. This redistribution makes the heart work harder. ⚠ Prinzmetal’s angina (choice A) is induced by coronary artery spasm which is reflected by either permanent blockade or blockade due to plaque. This usually occurs at rest. Its occurrence is increased in people who smoke, it may occur when patients are sitting or standing, this is not the case for angina decubitus. ⚠ Unstable angina (choice B) occurs at rest in patients with significant coronary artery disease. Angina occurs frequently for extended periods of more than 20 minutes with a week’s presence. ⚠ Stable angina (choice C) occurs due to exertion or stress. This type of angina is relieved by rest or by nitrates. ⚠ Variant angina (choice E) is just another name for Prinzmetal’s angina

🇨🇦 MCCQE1,2 | #Case_232 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 67-year-old male presents with complaint of anginal chest discomfort that comes and goes. He states it always happens when he is lying in his bed or watching TV lying on his couch and is unrelated to his exercise. Identify the type of angina patient is experiencing: a) Prinzmetal’s angina b) Unstable angina c) Stable angina d) Angina decubitus e) Variant angina

🇨🇦 MCCQE1,2 | #Case_231 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation The patient described has an inflammatory myopathy of the polymyositis/dermatomyositis (choice E) group. Proximal muscle involvement and elevation of serum muscle enzymes such as creatine kinase and aldolase are characteristic. Corticosteroids are the accepted treatment of choice. ⚠ It is extremely unlikely that Duchenne’s muscular dystrophy (choice A) would present after age 30. ⚠ Patients with myasthenia gravis (choice B) characteristically have ocular involvement, often presenting as ptosis and/or diplopia. ⚠ In amyotrophic lateral sclerosis (choice C) an abnormal neurologic examination with findings of upper or lower motor neuron dysfunction is characteristic. ⚠ The predominant symptom of aseptic necrosis (choice D) of the femoral head is pain rather than proximal muscle weakness. Elevated muscle enzymes are not characteristic

🇨🇦 MCCQE1,2 | #Case_231 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 44-year-old black female reports diffuse aching, especially in her upper legs and shoulders. The aching has increased, and she now has trouble going up and down stairs because of weakness. She has no visual symptoms, and a neurologic examination is normal except for proximal muscle weakness. Laboratory tests reveal elevated levels of serum creatine kinase and aldolase. Her symptoms improve significantly when she is treated with corticosteroids. Which one of the following is the most likely diagnosis? a) Duchenne’s muscular dystrophy b) Myasthenia gravis c) Amyotrophic lateral sclerosis d) Aseptic necrosis of the femoral head e) Polymyositis

🇨🇦 MCCQE1,2 | #Case_230 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation The patient has Dupuytren’s contracture, which is most common in men over 40 years of age. It is a progressive condition that causes the fibrous fascia of the palmar surface to shorten and thicken. It initially can be managed with observation, but corticosteroid injection and surgery may be needed. The condition will regress in 10% of patients. There is a 3%-33% prevalence of Dupuytren’s contracture in patients with diabetes mellitus; however, these patients tend to have a mild form of the disease with slow progression.; however, these patients tend to have a mild form of the disease with slow progression.

🇨🇦 MCCQE1,2 | #Case_230 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 43-year-old male complains of difficulty washing his face and combing his hair with his right hand. On examination a nodule, band, and slight contracture are noted in the palm proximal to the fourth finger. This patient’s condition is associated with which one of the following? a) Hyperparathyroidism b) Diabetes mellitus c) Hyperthyroidism d) Hypothyroidism e) Adrenal insufficiency

🇨🇦 MCCQE1,2 | #Case_229 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Although this patient has had a prior cesarean section, the possibility of a uterine scar separation is low. With the presence of ruptured membranes (ROM), a complete previa is unlikely. Although the uterus is tender, the patient is afebrile. There is literature to suggest that prolonged preterm ROM is associated with an increased risk of abruptio placentae. ⚠ Ruptured membranes with a complete previa is very unlikely. ⚠ Chorioamnionitis can be a complication of prolonged preterm rupture of membranes. It can be associated with contractions and uterine pain, but is usually not associated with vaginal bleeding. ⚠ Uterine scar separation can occur with a prior cesarean, but usually occurs in active labor. This patient is showing signs of early uterine activity at 32 weeks’ gestation, making this diagnosis unlikely. ⚠ HELLP syndrome is hemolysis, elevated liver enzymes, and low platelets

🇨🇦 MCCQE1,2 | #Case_229 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 At 32 weeks’ estimated gestational age, a 26-year-old multipara has been hospitalized for 10 days for premature rupture of membranes (PROM). She had a previous LTCS (Low Transverse Cesarean Section) because of arrested dilation. For 2 hours she has had light vaginal bleeding and contractions every 15 minutes. Over the past 30 minutes the bleeding has increased slightly, and she experiences lower abdominal pain between contractions. Her temperature is 37.0°C (98.6°F). The uterus is tender and the fetal heart rate is 170 bpm. Platelet count is 130x109/L, leukocyte count is 14.3x109/L, serum fibrinogen is 225 mg/dl, and the assay for fibrin split products is positive. Which of the following is the most likely diagnosis? a) Complete placenta previa b) Chorioamnionitis c) Abruptio placentae d) Uterine scar dehiscence e) HELLP syndrome

🇨🇦 MCCQE1,2 | #Case_228 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation Cellulitis in patients after breast lumpectomy is thought to be related to lymphedema. Axillary dissection and radiation predispose to these infections. Non-group A hemolytic Streptococcus is the most common organism associated with this infection. The onset is often several weeks to several months after surgery. Pneumococcus is more frequently a cause of periorbital cellulitis. It is also seen in patients who have bacteremia with immunocompromised status. Immunocompromising conditions would include diabetes mellitus, alcoholism, lupus, nephritic syndrome, and some hematologic cancers. Clostridium and Escherichia coli are most frequently associated with crepitant cellulitis and tissue necrosis. Pasteurella multocida cellulitis is most frequently associated with animal bites, especially cat bites.

🇨🇦 MCCQE1,2 | #Case_228 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 55-year-old white female presents with redness at the scar from a lumpectomy performed for stage I cancer of her right breast 4 months ago. The patient has completed radiation treatments to the breast. She is afebrile and there is no axillary adenopathy. There is no wound drainage, crepitance, or bullous lesions. Which of the following organisms would be the most likely cause of cellulitis in this patient? a) Non-group A Streptococcus b) Pneumococcus c) Clostridium perfringens d) Escherichia coli e) Pasteurella multocida

🇨🇦 MCCQE1,2 | #Case_227 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation Carcinoembryonic antigen (CEA) (choice D) is a marker for colon, esophageal, and hepatic cancers. It is expressed in normal mucosal cells and is overexpressed in adenocarcinoma, especially colon cancer. Though not specific for colon cancer, levels above 10 ng/mL are rarely due to benign disease. CEA levels typically return to normal within 4-6 weeks after successful surgical resection. ⚠ Prostrate-specific antigen (PSA) (choice A) is a marker that is used to screen for prostate cancer. It is elevated in more than 70% of organ-confined prostrate cancers. ⚠ Cancer antigen 27-29 (CA 27-29) (choice B) is a tumor marker for breast cancer. It is elevated in about 33% of early-stage cancers and about 67% of late-stage breast cancers ⚠ CA-125 (choice C) is a marker for ovarian cancer. Although it is elevated in 85% of ovarian cancers, it is elevated in only 50% of early-stage ovarian cancers. ⚠ Alpha-fetoprotein (choice E) is a marker for hepatocellular carcinoma and nonseminomatous germ cell tumor, and is elevated in 80% of hepatocellular carcinomas

🇨🇦 MCCQE1,2 | #Case_227 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 57-year-old black female has a partial resection of the colon for cancer. The surgical specimen has clean margins, and there is no lymph node involvement. There is no evidence of metastasis. You recommend periodic colonoscopy for surveillance, and also plan to monitor which one of the following tumor markers for recurrence? a) Prostate-specific antigen (PSA) b) Cancer antigen 27-29 (CA 27-29) c) Cancer antigen 125 (CA-125) d) Carcinoembryonic antigen (CEA) e) Alpha-fetoprotein

🇨🇦 MCCQE1,2 | #Case_226 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation The key to making a diagnosis of imperforate hymen, aside from the obvious finding on physical examination, lies in the systematic drawing of inferences. One can speculate that this patient’s recurrent crescendo abdominal cramping represents six menstrual sheddings, with no egress from the body. Her delay in menarche, despite normal growth parameters, offers another clue that the structural amenorrhea is present. Amounts of retained blood vary among patients; up to 3000 mL have been reported. A large volume can accumulate without causing any permanent damage, and subsequent fertility is usually normal. Hymenotomy will relieve the pressure, and normal menses should ensue

🇨🇦 MCCQE1,2 | #Case_226 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 13-year-old white female reports a 6 month history of intermittent abdominal cramping, with each episode becoming progressively worse. Based on her history, there is no obvious relationship to eating, voiding, or defecating. She report that she has not yet begun menstruating and is not sexually active. Her weight has been stable. She appears to be in mild emotional distress about being the “last girl in her class to have a period”. She is in no physical discomfort and her vital signs are normal. Secondary sexual characteristics appear to be developing normally. She is in the 57th percentile for height and the 65th percentile for weight. A complete physical examination confirms your presumptive diagnosis. The therapeutic procedure of choice would be: a) Appendectomy b) Colonoscopy c) Hymenotomy d) Cystoscopy e) Paracentesis

🇨🇦 MCCQE1,2 | #Case_225 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation ESR and CRP (choice B) together have a negative predictive value of almost 90 percent. Of these, the one with the greatest negative predictive value by it self is CRP. This means that negative results in CRP (usually less than 1mg/dL) and ESR (less than 20 mm/hr) mean that the patient is very unlikely to have septic arthritis. Also, CRP is better for monitoring response to treatment of septic arthritis than other methods. ⚠ The blood culture (choice A) of a patient with septic arthritis only turns out to be positive in 40-50 percent of the cases, giving it a very poor negative predictive value. ⚠ Gram stain of synovial fluid (choice C) is not reliable for the diagnosis or exclusion of septic arthritis. 50 percent of synovial fluid aspirations are sterile in cases of septic arthritis confirmed with clinical and laboratory findings, including positive blood culture. ⚠ Generally speaking, synovial fluid WBC counts (choice D) of more than 50 000 cells/microL with a predominance of polymorphonuclear leukocytes indicates a greater likelihood of the patient having septic arthritis. However, the synovial fluid WBC count is neither sensitive nor specific for the diagnosis of septic arthritis. It may happen to be much lower in unusual causes of bacterial arthritis (eg. Brucella), and it may exceed 50 000 cells/microL in patients with juvenile idiopathic arthritis, serum sickness, or reactive arthritis. ⚠ Normal X-ray (choice E) does not exclude the diagnosis of Septic Arthritis, therefore it has a poor negative predictive value. It does not add much to the diagnostic evaluation of Septic Arthritis. However, it may be a valuable adjunct to the examination of the hip, mainly to compare the contralateral joint. 🔖 Key point: ESR and CRP together have a negative predictive value of almost 90 percent. This means that negative results in CRP and ESR mean that the patient is very unlikely to have septic arthritis

🇨🇦 MCCQE1,2 | #Case_225 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 4-year-old female patient is brought to you by her parents on account of having knee pain over the past few days. The mother says she noticed the girl started limping 2 days ago, referring pain in her left knee and also had fever, which was not controlled by paracetamol. She refers that the girl has been irritable, has not been eating well, and she is not as happy as she usually is. She reports no relevant medical history. On examination, she has a temperature of 38.7°C, a heart rate of 123 bpm, and a respiratory rate of 23 /minute. You notice a markedly swollen, red, tender, painful and warm left knee, which has very limited and painful mobility and no other remarkable signs. Which of the following diagnostic tests is the best for excluding septic arthritis as a diagnosis? a) Blood culture b) ESR and CRP c) Gram stain of synovial fluid d) WBC count of the synovial fluid e) X-ray

🇨🇦 MCCQE1,2 | #Case_224 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Calcium channel blockers such as diltiazem are the first-line treatment for vasospastic angina. They are effective for both acute attacks and prophylaxis. In addition to CCBs, lifestyle modifications should be attempted, such as smoking cessation and abstaining from stimulants.

🇨🇦 MCCQE1,2 | #Case_224 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 48-year-old woman comes to the emergency room with chest pain. She describes the pain as a squeezing sensation in her chest with radiation to the left shoulder. The episode began about 15 minutes ago when she was sitting reading a book. She has had this pain before, typically in the evenings, though prior episodes usually resolved after a couple of minutes. Her pulse is 112/min, blood pressure is 121/87 mmHg,and respiratory rate is 21/min. An ECG shows ST-segment elevations in the inferior leads. Serum troponins are negative on two successive blood draws and the ECG shows no abnormalities 30 minutes later. Which of the following is the best long-term treatment for this patient's symptoms? A) Clopidogrel B) Diltiazem C) Aspirin D) Enalapril E) Metoprolol