Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_245 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Sitagliptin (choice B) is a dipeptidyl peptidase-4 (DPP-4) inhibitor that prevents breakdown of glucagon-like peptide-1 (GLP-1) and increases its level. GLP-1 is an incretin hormone with multiple physiologic effects. It stimulates the release of insulin from beta-cells and decreases glucagon secretion from alpha-cells in a glucose-dependent manner, resulting in a decrease in blood glucose levels. There is minimal risk of hypoglycemia with DPP-4 use. Two classes of antihyperglycemic agents increase the concentration of GLP-1: DPP-4 inhibitors and GLP-1 receptor agonists. Sitagliptin is not associated with weight gain which is an advantage in this case since the patient is obese. ⚠ Glimepiride (choice A), a sulfonylurea, lowers blood glucose level by stimulating the release of insulin from pancreatic beta-cells. It binds ATP sensitive potassium channel receptors, which causes membrane depolarization, increase in intracellular calcium, and secretion of insulin. The insulin release is not glucose dependant. It has no effect on alpha cells or glucagon release. ⚠ Repaglinide (choice E) acts by stimulating release of insulin from pancreatic beta-cells. It acts on a different binding site than the sulfonylurea. Repaglinide increases the amount of insulin released in a natural and physiological pulsatile pattern. It has shorter duration of action and is used for pre-prandial administration. It does not act on alpha cells. ⚠ Acarbose (choice D), an alpha-glucosidase inhibitor, delays the intestinal hydrolysis of oligo- and disaccharides. Consequently, the absorption of monosaccharides after a meal is delayed. It is used for control of prandial hyperglycemia. It does not act on pancreatic alpha or beta cells. ⚠ Pioglitazone (choice C) improves glycemic control by improving insulin sensitivity through its action on peroxisome proliferator-activated receptor (PPAR) gamma, and affects lipid metabolism through action on PPAR alpha. Together, these can increase glucose uptake and utilisation in the peripheral organs, decrease gluconeogenesis in the liver, thereby reducing insulin resistance and improve lipid profile. It has no action on pancreatic alpha or beta cells. 🔖Key point: Incretin mimetics, such as Exenatide, act on both alpha and beta cells of pancreas in glucose dependant manner and are associated with minimal risk of hypoglycaemia

🇨🇦 MCCQE1,2 | #Case_245 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 58-year-old man with type 2 diabetes mellitus, diagnosed 3 years ago, has come in for his annual check-up. He also has a history of hypertension and hyperlipidemia. He is on metformin 1000 mg twice a day. He is compliant with his medications but has a sedentary life style (body mass index = 31). His blood biochemistry is remarkable for glycated hemoglobin of 7.5%. You recommend addition of a second oral hypoglycemic agent. Which of the following hypoglycemic agents that acts on both alpha and beta cells of pancreas would be a suitable addition to his current management? a) Glimepiride b) Sitagliptin c) Pioglitazone d) Acarbose e) Repaglinide

🇨🇦 MCCQE1,2 | #Case_244 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation A COPD exacerbation can be triggered by a range of factors such as viral/bacterial infections, environmental irritants, CHF & PE. Exacerbations are indicated by an increase in coughing and sputum production/volume from baseline, sputum purulence; wheezing, chest tightness and fevers may also present. Investigations should include: CBC, Serum chemistries, ABG (if severe), ECG, CXR, Blood/Sputum cultures. Management should consist of: 1. An assessment of ABC’s; 2. Supplemental O2; 3. Bronchodilators by nebulizer (e.g. salbutamol, ipatropium); 4. Systemic corticosteroids (e.g. IV solumedrol); 5. Antibiotics (if indicated: i.e., purulent sputum, elevated WBC’s, fevers...etc) e.g. doxycycline, trimethoprim-sulfamethoxazole and amoxicillin clavulanate to cover the usual suspects (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis). ⚠ BiPaP (b) is reserved for severe exacerbations. ⚠ Option (e) is indicated in patients with deteriorating arterial blood gas (ABG) values, altered mental status (AMS) and progressive respiratory fatigue. 🔖 PEARL: Management of COPD exacerbation should include: ABC’s, O2, bronchodilators, systemic steroids, and antibiotics

🇨🇦 MCCQE1,2 | #Case_244 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 72-year-old woman with a history of COPD and arthritis presents to the ED with difficulty breathing. Her caregiver tells you she is “feverish”, breathing harder than normal and coughing up much more sputum which has turned thick and green. Your management plan should consist of: a) ABC’s, supplemental O2 and bronchodilation b) ABC’s, BiPAP c) ABC’s, O2, bronchodilators, systemic steroids, antibiotics d) ABC’s, systemic steroids and antibiotics e) Immediate intubation and admission to the ICU

🇨🇦 MCCQE1,2 | #Case_243 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This child has had a simple febrile seizure, the most common seizure disorder of childhood. Treatment includes finding a source for the fever; this should include a lumbar puncture if meningitis is suspected. The most common infections associated with febrile seizures include viral upper respiratory infections, otitis media, and roseola. Antipyretics are the first-line treatment. Antibiotics are indicated only for appropriate treatment of underlying infections. Phenytoin and carbamazepine are ineffective for febrile seizures. Phenobarbital is sometimes used for prevention of recurrent febrile seizures, but is not indicated as an initial therapy. Only 30%-50% of children with an initial febrile seizure will have recurrent seizures.

🇨🇦 MCCQE1,2 | #Case_243 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 15-month-old male is brought to the emergency department following a generalized tonic-clonic seizure at home. The parents report that the seizure lasted 5 minutes, with confusion for the next 15 minutes. This is the child’s first seizure. There is no family history of seizures. His medical history is normal except for a 1-day history of a URI. While initially lethargic in the emergency department, the child is now awake and playful, with a temperature of 39.5°C (103.2°F) and a normal examination. Appropriate diagnostic tests are performed, including a blood glucose level, which is 5.3 mmol/L (96 mg/dL). Which one of the following would be most appropriate to administer at this point? a) Phenytoin (Dilantin) intravenously b) Ceftriaxone (Rocephin) intravenously c) Acetaminophen orally d) Carbamazepine (Tegretol) orally e) Phenobarbital orally

🇨🇦 MCCQE1,2 | #Case_242 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation According to the clinical practice guidelines for management of persistent pain in older persons, tramadol has efficacy and safety similar to those of equianalgesic doses of codeine and hydrocodone. However, because of the threat of seizures (rare but potential), tramadol should be used with caution in patients with a history of seizure disorder or those taking other medications that lower seizure thresholds.

🇨🇦 MCCQE1,2 | #Case_242 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 74-year-old black female has moderately severe pain due to osteoarthritis. However, she is also on medication for a seizure disorder. When choosing medications to manage her chronic pain, which one of the following should be used with caution because of her history of seizures? a) Salsalate (Disalcid) b) Celecoxib (Celebrex) c) Hydrocodone (Lortab) d) Oxycodone (OxyContin) e) Tramadol (Ultram)

🇨🇦 MCCQE1,2 | #Case_241 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation ACE inhibitors can significantly worsen renal failure in patients with hypertension caused by renovascular disease. Hyperkalemia is an associated problem. Captopril renography is a useful diagnostic screening test.The other agents are useful for lowering blood pressure but may cause mild creatinine elevations. They do not, however, cause the significant elevations of creatinine seen with ACE inhibitors in cases of significant renovascular disease

🇨🇦 MCCQE1,2 | #Case_241 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 72-year-old white male has new-onset hypertension with a current blood pressure of 190/110 mm Hg. Which one of the following agents can be used as part of a test for diagnosing renovascular hypertension, but would also increase the risk for azotemia if used for treatment? a) Captopril (Capoten) b) Metoprolol (Lopressor) c) Clonidine (catapres) d) Furosemide (Lasix) e) Amlodipine (Norvasc)

🇨🇦 MCCQE1,2 | #Case_240 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation This patient’s symptoms are typical of a subacute, systemic illness with signs of anemia, a presentation associated with acute myeloid leukemia. This disease is more common in persons with Down syndrome. There are no urinary symptoms and the time course would not suggest a urinary tract infection. Chest pain or shortness of breath would be expected with myocarditis Other malignancies that are more common in those with Down syndrome are acute lymphocytic leukemia, testicular cancer, and liver cancer

🇨🇦 MCCQE1,2 | #Case_240 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 23-year-old male with Down syndrome is brought to your office by his parents. The patient has had a low grade fever (approximately 100°F) for 7 days. The fever is not associated with rhinorrhea, sore throat, cough, dysuria, or shortness of breath. The parents note that their son has complained of aches in various places and has not been eating well for several weeks. The physical examination is remarkable painless lumps in the neck, pale conjunctivae, petechiae on lower extremities and a 5 kg weight loss since his last visit one month ago.Which one of the following is most consistent with this patient’s symptoms? a) Acute myeloid leukemia b) Atypical pneumonia c) Hodgkin’s lymphoma d) Myocarditis e) Urinary tract infection

🇨🇦 MCCQE1,2 | #Case_239 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Liver enzymes should be monitored in individuals who are taking valproic acid or carbamazepine, but not lithium, which is excreted primarily through the kidney. ⚠A. Lithium may cause EKG changes such as flattening or inversion of T waves or, more seriously, sinus node dysfunction. ⚠B. Elevation of white blood count is possible while taking lithium. ⚠D. Hypothyroidism secondary to lithium can be detected by elevation of TSH. ⚠E. Renal function should be monitored every 3 months

🇨🇦 MCCQE1,2 | #Case_239 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 36-year-old male presents to your office with rapid speech, elevated mood, increased energy, poor sleep, and increased appetite. You consult a psychiatrist who recommends initiating medication treatment with lithium. The psychiatrist asks you to perform some baseline tests before starting the medication. All of the following tests should be done to appropriately monitor the patient taking lithium, except: a) Baseline EKG b) CBC c) Liver enzyme panel d) TSH e) BUN and creatinine level

🇨🇦 MCCQE1,2 | #Case_238 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation Acoustic neuroma symptoms are due to cranial nerve involvement and progression of tumor size. Hearing loss is present 95% of the time and tinnitus is very common. The loss is usually chronic (over 3 years) and as many as one-third of patients are unaware it has occurred. Vestibular nerve involvement most often causes mild unsteadiness and rarely has accompanying true vertigo. Trigeminal involvement can cause pain, paresthesias, or numbness of the face. Facial paralysis occurs 6% of the time. The diagnosis of acoustic neuroma is based on asymmetric sensorineural hearing loss or another cranial nerve deficit, with confirmation based on MRI with gadolinium contrast or a CT scan. The best initial screening laboratory test is audiometry, as only 5% of patients with acoustic neuroma will have a normal test. Sensorineural loss is usually in the higher frequencies. Brainstem-evoked response audiometry may be used as a further screening measure when there are unexplained symmetrics and standard audiometric testing

🇨🇦 MCCQE1,2 | #Case_238 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 58-year-old male who works with heavy machinery at a local factory presents to your office for evaluation of hearing loss of several years’ progression. He notes that the loss is mainly in the left ear and he also has mild tinnitus. He has had no trauma to his head and he has no history of ear infections. Examination of the ears reveals normal tympanic membranes and a neurologic examination is negative. When a tuning fork is placed in the center of his forehead, he says the sound is much louder on the right side (Weber test). Comparing sound in front of the ear to the sound when the tuning fork is placed on the mastoid (the Rinne test) reveals that air conduction is better than bone conduction in the left ear. Which one of the following is true regarding further evaluation and management? a) No treatment or further diagnostic studies are indicated b) A hearing aid plus better hearing protection is all that is needed c) Carotid ultrasonography should be ordered d) A tympanogram is indicated e) Audiometry is the best initial screening test

🇨🇦 MCCQE1,2 | #Case_237 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Severe hyperkalemia (> 6.0 mEq/L) requires aggressive treatment. Calcium gluconate has no effect on the plasma potassium level, but it should be given first, as it rapidly stabilizes the membranes of cardiac myocytes, reducing the risk of cardiac dysrhythmias. Therapies that translocate potassium from the serum to the intracellular space should be instituted next, as they can quickly (albeit temporarily) lower the plasma concentration of potassium. These interventions include sodium bicarbonate, glucose with insulin, and albuterol. Total body potassium can be lowered with sodium polystyrene sulfonate, but this takes longer to affect the plasma potassium level than translocation methods. In the most severe cases, acute hemodialysis can be instituted

🇨🇦 MCCQE1,2 | #Case_237 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 75-year-old female is admitted to the hospital with a change in mental status. The initial workup includes a chemistry profile that reveals a plasma potassium level of 6.4 mEq/L (N 3.7-5.2). Which one of the following should be given now to rapidly lower the plasma potassium level? a) Corticosteroids b) Albuterol c) Sodium polystyrene sulfonate d) 0.45% saline e) Acute hemodialysis

🇨🇦 MCCQE1,2 | #Case_236 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation There is no antidote for gasoline poisoning. Treatment consists of support of cardiovascular and respiratory functions. In cases of ingestion, do not induce emesis or use gastric lavage and do not administer activated charcoal. Gasoline is poorly absorbed from the stomach. Catharsis with magnesium or sodium sulfate is acceptable. If spontaneous vomiting occurs, watch for signs of pulmonary aspiration. All symptomatic patients should have a chest X-ray taken no sooner than two hours post ingestion, and should be observed in the emergency department for a period of six hours. The patient may be discharged with observation at home if asymptomatic throughout and X-ray is negative, as in this patient. In the presence of a positive two-hour X-ray, the patient should be admitted for monitoring of blood gases, repeat chest X-rays, and respiratory support if required. This child has no respiratory distress and Chest X-ray did not show any abnormalities, therefore, he should be discharged home (choice E). ⚠ Steroids (choice A) and Antibiotic prophylaxis (choice B) are of no proven benefit in gasoline and other hydrocarbon poisoning. ⚠ Induce vomiting to empty the stomach (choice C) is incorrect. Gasoline is poorly absorbed from the stomach and emesis should not be induced. Decontamination should focus on removing any remaining hydrocarbon that might be on the clothes or skin, in the correct clinical setting. ⚠ Admit to ward for observation (choice D) is unnecessary for a patient whose condition is consiered stable in the emergency room

🇨🇦 MCCQE1,2 | #Case_236 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 2-year-old toddler is brought to the emergency department eight hours after accidental ingestion of gasoline. On examination she is afebrile and has no respiratory distress. Chest x-ray is normal. Which one of the following is the most appropriate intervention? a) Oral corticosteroid treatment b) Antibiotic to prevent pneumonitis c) Induce vomiting to empty the stomach d) Admit to ward for observation only e) Discharge home, but to return if tachypneic