Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_193 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Asymptomatic persons between 50 and 80 years of age should be screened for colon cancer. A single fecal occult blood test (FOBT) performed in the office after a digital rectal examination is an inadequate screen, with significant false negative and false-positive rates. Annual six-sample FOBT (two samples from three different bowel movements) improves colon cancer detection but can still have false-negative results. If any of the six samples tests positive for occult blood, colonoscopy is recommended

🇨🇦 MCCQE1,2 | #Case_193 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 57-year-old male has laboratory screening performed prior to his annual examination. One of his six fecal occult blood tests is positive. A CBC, chemistry panel, lipid panel, and prostate-specific antigen level are all normal. Which one of the following would be the most appropriate course of action? a) Repeat the fecal occult blood testing in 3 months b) Perform a rectal examination in the office, and if a stool guaiac is negative repeat the fecal occult blood testing in 3 months c) Refer for colonoscopy d) Refer for flexible sigmoidoscopy e) Refer for pre- and post-contrast CT of the abdomen and pelvis

🇨🇦 MCCQE1,2 | #Case_192 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation The pattern of disease described in this diabetic man is consistent with unstable angina. Even though the electrocardiogram is unchanged presently, there is a high risk of progression of these symptoms to possible myocardial infarction. Therefore, the patient should be admitted to the hospital, monitored, and have his therapy adjusted. Many of these patients will require cardiac catheterization if their symptoms cannot be controlled with maximal medical therapy. At present, the patient is on submaximal therapy since he is only on propranolol, and may still benefit from the use of calcium channel blockers, nitrates, and aspirin. Furthermore, there is no indication from the question as to whether he is on maximal beta-blocker therapy, since his heart rate is not given. Doses of beta-blockers should be titrated to a resting heart rate of 55-60 bpm

🇨🇦 MCCQE1,2 | #Case_192 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 69-year-old man with diabetes mellitus had a myocardial infarction 2 years ago. He has had exertional angina since then and has been taking propranolol. During the past few days he has had one episode of chest pain at rest, two episodes postprandially and one at night. Electrocardiogram reveals an old myocardial infarction. The most appropriate treatment is to: a) Admit him immediately for cardiac monitoring and adjustment of therapy b) Admit him immediately for coronary artery bypass surgery c) Decrease the dosage of propranolol and adding nitrates and salicylates d) Increase the dosage of propranolol and having him return in 1 week e) Advise resting from work and sedation at night and digitalization

🇨🇦 MCCQE1,2 | #Case_191| #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This patient suffers from the condition called Restless Legs Syndrome (RLS). It is a neurological disorder characterized by an irresistible urge to move one's body to stop uncomfortable or odd sensations. It most commonly affects the legs, but can affect the arms, and other parts of the body. The symptoms are more severe at night and moving the affected body part provide temporary relief. RLS is categorized as either primary (idiopathic) or secondary to specific medical condition or the use of certain drugs. More than 60% of cases of RLS run in families and are inherited in an autosomal dominant or recessive fashion. Being diagnosed with RLS does not indicate or foreshadow another neurological disease. The management of this condition involves identifying the cause of symptoms when possible. The treatment process is designed to reduce symptoms severity and night-time awakenings. Improving the quality of life is another goal in treatment. There are non-pharmacological and pharmacological treatments. Stretching the leg muscles can bring temporary relief; exercising every day and avoiding heavy meals before bed are also helpful; but cardio and weight training to close to bed time can aggravate the patient’s condition (choice C). ⚠ Secondary conditions causing RLS include iron and vitamins deficiency. All patients with symptoms of RLS should be tested for iron deficiency (choice A). ⚠ Some techniques that can improve the symptoms are avoiding caffeine, alcohol, and tobacco (choice B). ⚠ Maintaining a schedule of relaxation techniques, soaking in a warm bath, or massaging the legs can all help to relief the symptoms (choice D). ⚠ For symptoms that occur in the evening, patients may find that activities which alert their mind, such as reading a book, crossword puzzles and watching TV, may reduce symptoms (choice E). 🔖Key point: Recognize, diagnose and manage restless leg syndrome

🇨🇦 MCCQE1,2 | #Case_191 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 48-year-old female comes to see you for a new patient visit. While you are taking the patient history you notice that she is constantly changing her position and moving her legs. She denied any chronic condition, illness or pain. The patient is not currently taking any medications and the physical and neurological exam were unremarkable. When you interrogate her about the symptoms you noticed, she said that she is been suffering with this disturbing sensation on her legs for years. She describes the symptoms as a crawling and tingling sensation in the legs that get relieved when she moves or changes her position. The symptoms have steady worsened with time, to the point that it is affecting her rest at night and she feels fatigued and sleepy during the day. She said she is not concerned about it because she knows that several family members have been suffering from similar symptoms for generations, but she would like to do something to relieve the symptoms and get a better night sleep. Which of the following managements is not recommended for this condition? a) Patient should be tested for iron deficiency b) Cut back on caffeine, alcohol, tobacco c) Stretching exercises, cardio, and weight training before bed time d) Relaxations techniques, warm bath, massages, hot and cold pads e) Find mind occupying activities like reading a book, working on puzzles, or watching TV

🇨🇦 MCCQE1,2 | #Case_190 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Age is your first tip-off: the older the patient is with any kind of breast problem, the more likely it is to be cancer. The description is that of inflammatory carcinoma (ductal carcinoma), where the permeation of skin lymphatics has given the edema, redness, fullness, and orange peel appearance. The thick, tumor-laden skin actually masks the underlying mass, which is felt as "fullness" rather than a discreet lump

🇨🇦 MCCQE1,2 | #Case_190 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 75-year-old woman has a red, swollen, warm, tender breast. She states that the condition has been present for at least several weeks, perhaps a month or two. The skin over the area looks like orange peel. On physical examination there is a fullness to the entire breast, with no discrete mass. Which of the following is the most likely diagnosis? a) Chronic cystic mastitis b) Inflammatory carcinoma of the breast c) Normal menopausal involutionary changes d) Pyogenic breast abscess e) Tuberculous or fungal breast abscess

🇨🇦 MCCQE1,2 | #Case_189 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Galactosemia (choice B) typically presents in the second half of the first week of life with features of hypoglycemia including vomiting, jaundice, cyanosis, jitteriness, and seizures. The liver is usually enlarged. Urine of patients with galactosemia usually contains reducing substances (galactose) but is devoid of ketone bodies. Our patient showed most of these features and galactosemia is the most likely cause of hypoglycemia. ⚠ Transient neonatal hypoglycemia (choice A) is not the correct choice. Hepatomegally and demonstration of reducing substance in urine make the diagnosis of transient neonatal hypoglycemia unlikely. Urine of patients with transient neonatal hypoglycemia is not expected to contain any reducing substance (sugars) because blood glucose is low i.e. much lower than renal threshold for glucose reabsorption. Also hepatomegaly is not a feature of transient neonatal hypoglycemia because the basic etiology of this disorder is reduced liver glycogen stores due to immaturity of the responsible enzyme systems. ⚠ Type I Glycogen Storage Disease (choice C) is not the correct choice. Type I glycogen storage disease usually presents at the age of three to four months. Urine of patients with this disease is not expected to contain reducing substances because blood glucose is low i.e. much lower than renal threshold for glucose reabsorption. ⚠ Hereditary Fructose Intolerance (HFI) (choice D) is not the correct choice. Patients with HFI remain asymptomatic until foods containing fructose like table sugar or fruits are introduced. Our patient is exclusive breast-fed. ⚠ Hyperinsulinism (choice E) is not the correct choice. Hepatomegaly and presence of reducing substances in urine make hyperinsulinism an unlikely cause of hypoglycemia in this patient. Urine of patients with this disorder is not expected to contain reducing substances because blood glucose is low i.e. much lower than renal threshold for glucose reabsorption. 🔖 Key point: Demonstration of a reducing substance in urine of a neonate with hypoglycemia makes galactosemia a highly likely diagnosis

🇨🇦 MCCQE1,2 | #Case_189 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A six-day-old boy was brought to hospital because of episodes of vomiting, cyanosis, and jitteriness and hepatomegally. His mother was not diabetic and he was a full-term baby of normal birth weight and he was exclusively breast-fed. With appropriate work-up, the diagnosis of hypoglycemia was established. Urinalysis showed presence of reducing substance but no ketonuria. Which of the following disorders is the most likely cause of hypoglycemia in this patient? a) Transient neonatal hypoglycemia b) Galactosemia c) Type I Glycogen Storage Disease (Glucose-6-Phosphatase deficiency, Von Gierke Disease) d) Hereditary Fructose Intolerance (HFI) e) Hyperinsulinism

🇨🇦 MCCQE1,2 | #Case_188 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation This patient’s most likely diagnosis is von Willebran’s diease (vWD). It is an inherited hemorrhagic disorder caused by a deficiency or dysfunction of the protein von Willebrand factor (vWF). Consequently, defective vWF interaction between platelets and the vessel wall impairs primary hemostasis. It presents with easy bruising, prolonged bleeding after minor skin trauma, severe hemorrhage after surgeries, heavy bleeding after tooth extraction, and menorrhagia in women. Screening tests typically include prothrombin time (PT), activated partial thromboplastin time (aPTT), FVIII coagulant activity, ristocetin cofactor (RCoF) activity, and concentration of vWF antigen. Levels of vWF vary with physiologic stress; plasma levels may increase with estrogens, vasopressin, growth hormone, and adrenergic stimuli. Thus, vWF levels may intermittently be normal in patients with vWD. Since factor VIII is bound to vWF, which protects the factor VIII from rapid breakdown within the blood, it may be normal or decreased depending on the vWF status, this also means that activated partial thromboplastin time, a performance indicator of intrinsic activation pathway may be normal or increased in patients with vWD. Bleeding time is usually prolonged in patients with vWD. Prothrombin time is not affected by vWD. Therefore, among the choices given, choice A (PT normal, aPTT increased, BT increased) is the best answer. ⚠ PT increased, aPTT increased, BT normal (choice B) is incorrect. In vWD bleeding time is increased while the prothrombin time is normal. ⚠ PT increased, aPTT normal, BT increased (choice C) is incorrect. Prothrombin time is a measure of the extrinsic pathway that measures factors I, II, V, VII, and X. It is not affected by vWD. ⚠ PT normal, aPTT increased, BT normal (choice D) is consistent with hemophilia; it is not seen in vWD as the bleeding time is likely to be increased. ⚠ PT increased, aPTT increased, BT increased (choice E) is seen in disseminated intravascular coagulation, not in vWD. 🔖Key point: Von Willebrand disease is an inherited hemorrhagic disorder caused by a deficiency or dysfunction of the protein von Willebrand factor. In this disease, prothrombin time is normal, activated partial thromboplastin time may be normal or increased, bleeding time is usually increased.

🇨🇦 MCCQE1,2 | #Case_188 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 21-year-old white female college student presents with heavy bleeding post-appendectomy. Her past medical history reveals easy bruising and an incidence of massive bleeding following a tooth extraction 5 years ago. Family history is remarkable for a father with a history of easy bruising. Which of the following would be revealed by this patient's laboratory tests? [Increased = I; Decreased = D; N = Normal; PT = Prothrombin time; PTT = Partial Thromboplastin time; BT = Bleeding Time] a) PT: N, PTT: I, BT: I b) PT: I, PTT: I, BT: N c) PT: I, PTT: N, BT: I d) PT: N, PTT: I, BT: N e) PT: I, PTT: I, BT: I

🇨🇦 MCCQE1,2 | #Case_187 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation Sstatus epilepticus is prolonged, repetitive seizure activity that lasts more than 5-10 minutes, without spontaneous cessation, or recurrent seizures without full return to consciousness inter-ictally (between seizures). Status epilepticus is a medical emergency with a significantly poor outcome; it can result in death if not treated aggressively. Tonic-clonic seizure - specific movements of the arms and legs and/or the face may occur with loss of consciousness. The seizure usually lasts 5 to 20 minutes. Absence seizures cause a short loss of consciousness (just a few seconds) with few or no symptoms Atonic and myoclonic seizures are not characterized by loss of consciousness.

🇨🇦 MCCQE1,2 | #Case_187 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 58-year-old male with a history of seizure attacks suffered from a 30 min loss of consciousness with repetitive seizures with no recovery of consciousness between attacks. What is the disorder this patient is suffering from? a) Tonic-clonic seizure b) Absence seizure c) Atonic seizure d) Myoclonic seizure e) Status epilepticus

🇨🇦 MCCQE1,2 | #Case_186 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This patient’s seizure, tremors, and diaphoresis 48 hours after admission are most likely symptoms of delirium tremens. It is the most severe form of ethanol withdrawal manifested by altered mental status and sympathetic overdrive. This is a medical emergency with high mortality that requires immediate diagnosis and treatment. Benzodiazepines are commonly used in the treatment of delirium tremens, and they are cross-tolerant with alcohol and much safer than other sedatives. If lorazepam is given, initially the best dosage is 12 doses of 2-4 mg of lorazepam every 4 hours (choice C). In case diazepam is given as the choice, it is important to know that 20 mg oral diazepam can be given every 1-2 hours until therapeutically adequate concentrations are reached to improve the clinical condition. if oral diazepam is not tolerated: diazepam 2-5 mg IV/min- maximum 10-20 mg q1h can be given. For patients >65 yrs old or those with severe liver disease, severe asthma, or respiratory failure, use short acting benzodiazepine such as lorazepam PO/SL/IM 1-4 mg q1-2h. Please note that diazepam should never be administered intramuscularly as absorption is erratic. ⚠ 1mg haloperidol every 8 hours (choice A) is incorrect. Haloperidol is used as an adjunctive therapy in patients who have hallucination or are combative. Benzodiazepines are still the best drugs for the management of delirium tremens. ⚠ Intravenous hydration with 5% dextrose in water (choice B) is incorrect. While patients with delirium tremens are often dehydrated and intravenous fluid support is in order, dextrose should not be administered before thiamine is given because there’s a risk of precipitating Wernicke crisis. Normal saline should be given and for hypoglycemic patients 5% dextrose may be added after thiamine has been offered. ⚠ Disulfiram, 500 mg per day (choice D) is incorrect. Disulfiram is used to support treatment of alcoholism by inhibiting acetaldehyde dehydrogenase, thus causing an unpleasant reaction when alcohol is consumed. It is not useful in the management of delirium tremens. ⚠ 1mg of lorazepam every 6 hours (choice E) is incorrect. This dose would be too little in a patient with delirium tremens. Even in a patient who is calm and cooperative with low risk of delirium tremens, the advised dose is 1 mg of lorazepam every hour 🔖Key point: Delirium is the most severe form of ethanol withdrawal manifested by altered mental status and sympathetic overdrive. It is a medical emergency that is initiall best treated with benzodiazepines. Every 4 hours about 12 doses of 2-4 mg of lorazepam should be given

🇨🇦 MCCQE1,2 | #Case_186 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 57-year-old male, who had been admitted to your department for management of perforated diverticulitis 48 hour ago, has just suddenly developed a seizure. He has tremors, and is sweating profusely. Vital signs are: temperature 38.6°C, BP is 155/90 mmHg, heart rate is 115 bpm, and respirations are 20/min. After reviewing patient's ED chart, you suspect alcohol withdrawal. What is the most appropriate initial treatment? a) 1mg haloperidol every 8 hours b) Intravenous hydration with 5% dextrose in water c) 12 doses of 2 mg of lorazepam every 4 hours d) Disulfiram, 500 mg per day e) 1mg of lorazepam every 6 hours

🇨🇦 MCCQE1,2 | #Case_185 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation This patient has conversion aphonia (choice E). In this condition, the patient loses his or her spoken voice, but the whispered voice is maintained. The vocal cords appear normal, but if observed closely by an otolaryngologist, there is a loss of vocal cord adduction during phonation, but normal adduction with coughing or throat clearing. This often occurs after a traumatic event (in this case a divorce). ⚠ Muscle tension aphonia (choice A) presents with strained, effortful phonation, vocal fatigue, and normal vocal cords. It is caused by excessive laryngeal or extralaryngeal tension associated with a variety of factors, including poor breath control and stress, for example. ⚠ The patient with laryngopharyngeal reflux (choice B) presents with a raspy or harsh voice. The hoarseness is usually worse early in the day and improves as the day goes by. There is usually associated heartburn, dysphagia, and/or throat clearing. ⚠ The patient with spasmodic dysphonia (choice C) (also known as laryngeal dystonia) has a halting, strangled vocal quality. It is a distinct neuromuscular disorder of unknown cause. Uncontrolled contractions of the laryngeal muscles cause focal laryngeal spasm. ⚠ The hoarseness of vocal abuse (choice D) is usually worse later in the day after effortful singing or talking. The history usually reveals vocal cord abuse, such as with an untrained singer or some other situation that increases demands on the voice. Nodules or cysts may be seen on the vocal cords with this condition

🇨🇦 MCCQE1,2 | #Case_185 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 31-year-old female who is a successful professional photographer complains of hoarseness that started suddenly 3 weeks ago. She says she can remember exactly what day it was, because her divorce became final the next day. The day the problem began, she was only able to whisper from the time she woke up, and she is able to speak only in a weak whisper while relating her history. She does not appear to strain while speaking. She does not smoke, has had no symptoms of an upper respiratory infection, and has no pain, cough, or wheezing. She is on a proton pump inhibitor prescribed by an urgent care provider 2 weeks ago. This has not changed her symptoms. She takes no other medications and has no known allergies. A head and neck examination, including indirect laryngoscopy, is within normal limits.Which one of the following is the most likely diagnosis? a) Muscle tension aphonia b) Laryngopharyngeal reflux c) Spasmodic dysphonia d) Vocal abuse e) Conversion aphonia

🇨🇦 MCCQE1,2 | #Case_184 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation In a patient complaining of flashes of light and a visual field defect, retinal detachment is the most likely diagnosis. Many cases of vitreous detachment are asymptomatic, and it does not cause sudden visual field defects in the absence of a retinal detachment. A vitreous hemorrhage would cause more blurring of vision in the entire field of vision. Ocular (retinal) migraine causes binocular symptoms

🇨🇦 MCCQE1,2 | #Case_184 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 67-year-old female comes to your office because she noticed flashing lights in her left eye 2 hours ago, and since then has had decreased vision in the lateral aspect of that eye. On examination she has a blind spot in the lateral visual field of her left eye. Her fundus is difficult to examine because of an early cataract. Which one of the following is the most likely diagnosis? a) Posterior vitreous detachment b) Vitreous hemorrhage c) Macular degeneration d) Ocular migraine e) Retinal detachment