Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_205 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation Hypernatremia is plasma Na concentration > 145 mEq/L caused by a deficit of water relative to solute. A major symptom is thirst; other clinical manifestations are primarily neurologic (due to an osmotic shift of water out of cells), including confusion, neuromuscular excitability, seizures, and coma. Diagnosis is by measuring serum Na. Severely dehydrated infants must have their circulating blood volume restored first, usually with 0.9% saline in aliquots of 20 mL/kg IV. Treatment is then with 5% D/W/0.3% to 0.45% saline solution IV in volumes equal to the calculated fluid deficit, given over 2 to 3 days to avoid a rapid fall in serum osmolality, which would cause rapid movement of water into cells and potentially lead to cerebral edema. Maintenance fluids should be provided concurrently. The goal of treatment is to decrease serum Na by about 10 mEq/L/day

🇨🇦 MCCQE1,2 | #Case_205 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 6-month-old girl presents with vomiting and diarrhea of acute onset. Her systolic blood pressure is 40 mm Hg, pulse is 160/minute, she has poor peripheral circulation and is very lethargic. Her serum sodium concentration is 158 mmol/L. Which one of the following is the best initial management? a) Intravenous 0.9% saline in aliquots of 20 mL/kg b) Intravenous 5% D/W/0.3% to 0.45% saline solution c) Oral solution containing 50 mmol sodium per liter d) Septic workup e) Hydrocortisone 200 mg intravenously

🇨🇦 MCCQE1,2 | #Case_204 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This patient has diabetes with proteinuria and likely has nephrotic syndrome. Among the many sequelae of nephrotic syndrome is hypercoagulability secondary to the loss of antithrombotic proteins in the urine (protein C, S, and antithrombin). These patients are at increased risk for arterial and venous thrombotic complications, including myocardial infarction, pulmonary embolism, deep vein thrombosis, and, as is the case with this patient, unilateral renal vein thrombosis (RVT). Classically, patients with RVT present with flank pain (secondary to distention of the renal capsule), hematuria, and evidence of renal impairment. Timely diagnosis via renal ultrasound, CT, or direct venography, as well as treatment with heparin, is crucial. The disruption of renal blood flow can lead to permanent damage. ⚠Answer A is incorrect. Analgesics and angiotensin-converting enzyme (ACE) inhibitors would do little to address the underlying pathology in this patient. Moreover, ACE inhibition may worsen this patient’s renal failure by decreasing the contralateral kidney’s hyper-filtration. ⚠Answer B is incorrect. These modalities are important tools for the diagnosis and treatment of nephrotic syndrome. High-dose corticosteroids are used to treat minimal change disease, among other causes of nephrotic syndrome, but they will do little to address this patient’s acute complication. ⚠Answer D is incorrect. Spiral CT is useful in diagnosing renal calculi, and administration of a thiazide diuretic is helpful in treating chronic stone formation by decreasing hypercalciuria. This patient does not have findings that are consistent with nephrolithiasis; thus,these treatments would not be helpful. ⚠Answer E is incorrect. Urine culture and antibiotics are appropriate diagnostic and treatment modalities to address acute pyelonephritis. This patient is afebrile, lacks costovertebral angle tenderness, and does not have dysuria or pyuria

🇨🇦 MCCQE1,2 | #Case_204 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 56-year-old woman with a history of diabetes and proteinuria presents to the ED complaining of right groin pain and decreased urine output for the past day. She denies any trauma, fever, or history of kidney stones or urinary tract infections. Her temperature is 37.2°C(99.0°F), blood pressure is 146/90 mm Hg, pulse is 104/min, and respiratory rate is 16/min. Heart and lung examinations are normal; she has no visible rashes and no costovertebral angle tenderness. There is trace ankle edema bilaterally. Laboratory tests show: Na+ 134 mEq/L K+ 4.9 mEq/L Cl− 100 mEq/L HCO3− 24 mEq/L Blood urea nitrogen 38 mg/dL Creatinine 1.6 mg/dL Albumin 2.2 g/dL Urinalysis 3+ blood, 4+ protein, no WBCs, no stones What is the most appropriate next step in management of this patient’s condition? (A) Analgesics and angiotensin-converting enzyme inhibitors (B) Kidney biopsy and high-dose corticosteroids (C) Renal vein ultrasound and heparin (D) Thiazides and spiral CT of the pelvis (E) Urine culture and oral quinolones

🇨🇦 MCCQE1,2 | #Case_203 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation This patient presents with psychiatric symptoms suggestive of a mania. Moods swings, irritability, decreased need to sleep, racing thoughts, excitation, and other symptoms usually associated with bipolar disorder are seen in many patients treated with prednisone (choice D) or other corticosteroids, especially with doses higher than 40 mg per day. Psychiatric side effects associated with corticosteroids are reversible with discontinuation of the drug or significant reduction in dose. Other common side effects of corticosteroids to be aware of are hypertension, hirsutism, obesity, diabetes mellitus, peptic ulcer disease, fatty liver, leukocytosis, oral candidiasis, myopathy, osteoporosis, and cataracts. ⚠ Gold salts (choice A) can cause coloring of the skin in shades of mauve to a purplish dark grey when exposed to sunlight, if the salts are taken on a regular basis over a long period of time. They can also cause kidney damage, pruritus, and oral ulcers. ⚠ Methotrexate (choice B) can cause ulcerative stomatitis, leukopenia with immunosuppression, pneumonitis, pulmonary fibrosis, dizziness, and kidney failure. ⚠ Meloxicam (choice C) like most NSAIDs can cause peptic ulcers, tinnitus, and skin rash. However, compared to other NSAIDs its side effects profile is favourable. ⚠ Minocycline (choice E) can cause diarrhea, photosensitivity, dizziness, lupus, blue-gray skin, and like other tetracyclines it can cause discoloration of teeth, especially in children. 🔖 Key point: High dose corticosteroids can cause psychiatric adverse effects, particularly mood changes, which are reversible with discontinuation of the drug or significant reduction in dose

🇨🇦 MCCQE1,2 | #Case_203 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 67-year-old female presents to your department with her husband and they report that she has been experiencing mood swings with unusually frequent irritability, decreased sleep need, racing thoughts, and excitation. The patient has a 4-year history of rheumatoid arthritis and was recently started on a new medication. Which of the following is the most likely medication the patient is being treated with? a) Gold salts b) Methotrexate c) Meloxicam d) Prednisone e) Minocycline

🇨🇦 MCCQE1,2 | #Case_202 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Erythema nodosum (EN) is a panniculitis most often appearing on the shins. In 35% - 55% of cases, no cause is found. EN has been associated with pregnancy and oral contraceptives (choice C). Other drugs including sulfonamides, bromides, iodides, and omeprazole have been associated with EN. Statins have not been associated with EN. Infectious agents associated with EN include beta-hemolytic streptococci, Mycobacterium, Yersinia, fungi, syphilis, Campylobacter, hepatitis C, and Epstein-Barr virus. Inflammatory conditions associated with EN include inflammatory bowel disease, sarcoidosis, Lofgren’s syndrome and Behçet’s syndrome. EN is usually self-limited or resolves with treatment of the underlying disorder. Glucocorticoids are usually not necessary for idiopathic EN.

🇨🇦 MCCQE1,2 | #Case_202 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 32-year-old female presents with bilateral pretibial tender, mildly red nodules 2 - 4 cm in diameter. A nodule that appeared earlier resolved, leaving a “bruised” area. She had a similar problem once when she was pregnant but it resolved spontaneously. Her medications include lovastatin (Mevacor) for hyperlipidemia and a low-dose oral contraceptive prescribed 5 months earlier. Her past history and a review of systems are otherwise unremarkable. The most appropriate next step would be to: a) Order a serum creatinine phosphokinase level b) Obtain a cervical culture for gonorrhea c) Discontinue her oral contraceptives d) Discontinue lovastatin e) Treat with glucocorticoids

🇨🇦 MCCQE1,2 | #Case_201 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Fat-pad atrophy is a common cause of heel pain in the geriatric patient, and in contrast to plantar fasciitis, causes pain as the day progresses. ⚠ Plantar fasciitis classically presents as morning pain. ⚠ Tarsal tunnel syndrome causes neuropathic pain in the distribution of the posterior tibial nerve, radiating into the plantar aspect of the foot toward the toes. ⚠ Lumbar radiculopathy involves pain radiating down the leg into the heel, and is usually associated with weakness of dorsiflexion of the big toe and a decreased ankle reflex. ⚠ Multiple myeloma would be an extremely unusual cause of heel pain; heel pain associated with cancer more commonly presents nocturnally

🇨🇦 MCCQE1,2 | #Case_201 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An 80-year-old male presents with the chief complain of a “bone spur”, describing mid-heel pain that worsens as the day progresses. The pain is not relieved with ibuprofen. Examination reveals tenderness in the central aspect of the heel and a radiograph of the foot is unremarkable. The most likely diagnosis is: a) Multiple myeloma b) Fat-pad atrophy c) Tarsal tunnel syndrome d) S1 radiculopathy e) Plantar fasciitis

🇨🇦 MCCQE1,2 | #Case_200 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation The patient is described as a homosexual male with both subacute and acute neurologic abnormalities. Furthermore, the neurologic signs and symptoms described clearly indicate focal findings as would be seen with a mass lesion. In a homosexual man, one would suspect the possibility of toxoplasmosis, and a CT scan of the head should be performed. Toxoplasmosis would be revealed as multiple ring-enhancing lesions. ⚠ Bilateral carotid angiography and an electroencephalogram are not indicated at this time. ⚠ A lumbar puncture would in fact be contraindicated given the possibility of a mass lesion and possible increased intracranial pressure. ⚠ While order a serum test for HIV antibodies may be appropriate it will not be most useful in evaluating his current signs and symptoms

🇨🇦 MCCQE1,2 | #Case_200 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 39-year-old man is brought to the emergency department by his same sex partner because of confusion, diplopia and mild right arm weakness. On examination the patient is somewhat agitated and shows confusion for recent events. There is decreased pupillary response on the left with some paresis of lateral gaze on the right. Temperature is 38.3°C (101.0°F). Peripheral leukocyte count is increased. The most appropriate next step in evaluation of his neurologic signs and symptoms is: a) Bilateral carotid arteriography b) CT scan of the head c) Electroencephalography d) Lumbar puncture e) Serum test for HIV antibodies

🇨🇦 MCCQE1,2 | #Case_199 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Propranolol, like other nonspecific beta blockers, may cause bronchospasm by blocking the beta receptors in the bronchial tree. Beta stimulation in the lungs produces bronchodilation, and its blockade leads to bronchoconstriction. In fact, propranolol is contraindicated in patients with known asthma or chronic obstructive pulmonary disease (COPD)

🇨🇦 MCCQE1,2 | #Case_199 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 39-year-old automobile mechanic presents because of the new onset of wheezing. His medications are propranolol, enalapril, hydrochlorothiazide, ranitidine and occasional pseudoephedrine for symptoms of allergic rhinitis. On physical examination, he appears comfortable. His blood pressure is 134/88 mm Hg, pulse is 68/min, and respirations are 18/min. On lung examination, soft expiratory wheezes are heard throughout both lung fields. Which of the following medications is most likely contributing to his wheezing? a) Enalapril b) Hydrochlorothiazide c) Propranolol d) Pseudoephedrine e) Ranitidine

🇨🇦 MCCQE1,2 | #Case_198 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation The combination of halitosis, late regurgitation of undigested food, and choking suggests Zenker’s diverticulum. Patients may also have dysphagia and weight loss. The diagnosis is usually made with a barium swallow. The treatment is surgical

🇨🇦 MCCQE1,2 | #Case_198 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 60-year-old male indicates that he occasionally brings up what appears to be undigested food long after his meal. He also admits that he sometimes chokes on food, and that his wife says he has bad breath. The most likely diagnosis is: a) Achalasia b) Esophageal reflux c) Cancer of esophagus d) Zenker’s diverticulum e) Large cervical bone spur

🇨🇦 MCCQE1,2 | #Case_197 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation There are many drugs that can induce a syndrome resembling systemic lupus erythematosus, but the most common offender is procainamide, followed by hydralazine. There is a genetic predisposition for this drug-induced lupus, determined by drug acetylation rates. Polyarthritis and pleuropericarditis occur in half of patients, but fortunately, CNS and renal involvement are rare. While all patients with this condition have positive ANAs and most have antibodies to histones, antibodies to double-stranded DNA and decreased complement levels are rare, which distinguishes drug-induced lupus from idiopathic lupus. The best initial management is to withdraw the drug, and most patients improve in a few weeks. For those with severe symptoms, a short course of corticosteroids is indicated. Once the offending drug is discontinued, symptoms seldom last beyond 6 months.

🇨🇦 MCCQE1,2 | #Case_197 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 For several years, a hypertensive 65-year-old female has been treated with hydrochlorothiazide, 25 mg/day; atenolol (Tenormin), 100 mg/day; and hydralazine (Apresoline), 50 mg 4 times/day. Her blood pressure has been well controlled on this regimen. Over the past 2 months she has experienced malaise, along with diffuse joint pains that involve symmetric sites in the fingers, hands, elbows, and knees. A pleural friction rub is noted on examination. Laboratory testing shows that the patient has mild anemia and leucopenia, with a negative rheumatoid factor and a positive antinuclear antibody (ANA) titer of 1:640. Which one of the following would be the most appropriate initial treatment? a) Discontinue the thiazide diuretic and switch to a loop diuretic such as furosemide (Lasix) b) Discontinue the hydralazine c) Begin treatment with prednisone, 40 mg/day orally d) Treat with hydroxychloroquine (Plaquenil), 400 mg/day e) Obtain renal function studies and anticipate that a renal biopsy will be needed

🇨🇦 MCCQE1,2 | #Case_196 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Torsion is much more common than orchitis in childhood and this should be kept in mind when considering the diagnosis of testicular pain. ⚠A. Elevation of the testicle results in pain relief in epididymitis and orchids but not improve torsional pain ⚠C. Only a few hours remain for intervention before irreversible damage occurs. ⚠D. In this patient orchitis is most likely caused by viral infections, which would not respond to antibiotic treatment.(In mumps orchitis, 4 out of 5 cases occur in prepubertal males (younger than 10 years). In bacterial orchitis, most cases are associated with epididymitis (epididymo-orchitis), and they occur in sexually active males older than 15 years or in men older than 50 years with benign prostatic hypertrophy) ⚠E. As mumps is a primary cause of orchitis, the widespread use of this vaccine has decreased the number of cases of orchitis.

🇨🇦 MCCQE1,2 | #Case_196 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 5-year-old boy develops the acute onset of testicular pain. There is no fever or history of trauma. You are considering both testicular torsion and orchitis. Which of the following is false? a) The pain of orchitis is relieved by gently elevating the testicle b) Orchitis is more common in childhood than torsion c) Irreversible damage may occur as a result of testicular torsion d) When orchitis is diagnosed in prepubertal males, antibiotics are most commonly unnecessary e) The incidence of orchitis has diminished since the introduction of the measles/mumps/rubella (MMR) vaccine