Case-based MCQ

🇨🇦 MCCQE1,2 | #Case_48 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 16-year-old white female is brought to your office because she has been “passing out”. She tells you that on several occasions while playing in the high-school band at the end of the half-time show she has “blacked out”. She describes feeling lightheaded with spots before her eyes and tunnel vision just prior to falling. Friends in the band have told her that she appears to be pale and sweaty when these episodes occur. No seizure activity has ever been observed. In each instance she regains consciousness almost immediately; there is no postictal state. She has been seen in the emergency department for this on two occasions with normal vital signs, physical findings, and neurologic findings. A CBC, a metabolic profile, and an EKG are also normal. Which one of the following tests is most likely to yield the correct diagnosis? a) A sleep-deprived EEG b) 24-hour Holter monitoring c) A pulmonary/cardiac stress test d) An echocardiogram e) Tilt table testing

🇨🇦 MCCQE1,2 | #Case_47 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ E 🔎 Explanation Sarcoidosis is a disease of unknown cause characterized by the presence of noncaseating epithelioid granulomas; it involves many different organ systems. The lungs are commonly involved, with bilateral hilar lymphadenopathy being commonly present and pulmonary infiltrates and fibrosis somewhat typical. Other frequent areas of involvement include the skin, central nervous system, eyes, liver, heart, salivary glands, kidneys, muscles, and bones. When the disease is limited to asymptomatic hilar adenopathy, it is termed stage I and no treatment has been shown to be beneficial. The most appropriate management of stage I patients is routine follow-up.

🇨🇦 MCCQE1,2 | #Case_47 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 25-year-old clinically healthy black female is involved in a minor auto accident. Chest radiographs obtained after the wreck reveal bilateral hilar lymphadenopathy. She has no history of environmental exposures and has no symptoms. A physical examination is completely normal. Your initial workup includes a normal comprehensive metabolic panel, CBC, and urinalysis; a negative tuberculin skin test; a normal EKG; and normal pulmonary function tests. A transbronchial lung biopsy specimen reveals a noncaseating epithelioid granuloma.Which one of the following would be the most appropriate treatment at this time? a) Long-term high-dose systemic corticosteroids b) Pulsed doses of systemic corticosteroids c) Inhaled corticosteroids d) Oral methotrexate weekly e) Observation only

🇨🇦 MCCQE1,2 | #Case_46 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This is a classic incidentaloma. Nodules are detected in up to 50% of thyroid sonograms and carry a low risk of malignancy (< 5%). If the TSH level is normal, nuclear scanning and further thyroid studies are not necessary. Nodules smaller than 1 cm are difficult to biopsy and thyroid surgery is not indicated for what is almost certainly benign disease. It is reasonable to follow small nodules with clinical examinations and periodic sonograms. Note: 🔹all patients with thyroid nodules require evaluation of serum TSH and ultrasound 🔹any nodule > 5 mm with suspicious sonographic features (particularly microcalcifications) should undergo FNA 🔹anynodule > 1cm should undergo FNA 🔹when performing repeat FNA on initially non-diagnostic nodules, U/S-guided FNA should be employed 🔹nuclear scanning has minimal value in the investigation ofthe thyroid nodule

🇨🇦 MCCQE1,2 | #Case_46 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 45-year-old white male undergoes a health screening at his church. He has a carotid Doppler study, abdominal ultrasonography, heel densitometry, and a multiphasic blood panel. He receives a report indicating that all of the studies are normal, but a 0.7-cm thyroid nodule was noted. The TSH level is normal. He schedules a visit with you and brings you the report. A neck examination and ENT examination are normal, and you do not detect a nodule. His past medical history and family history are unremarkable. You recommend: a) A radionuclide thyroid scan b) T3, T4, and calcitonin levels c) Repeat ultrasonography in 6-12 months d) A fine-needle biopsy e) Hemithyroidectomy

🇨🇦 MCCQE1,2 | #Case_45 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation This patient’s diagnosis is most likely anorexia nervosa. The DSM-V criteria for diagnosing anorexia nervosa include refusal to maintain appropriate body weight, intense fear of becoming fat, undue influence of body weight or shape on self-evaluation, and amenorrhea.Anorexia nervosa can have serious implications if its duration and severity are significant. Medical complications resulting from semi-starvation and overexercising affect virtually every organ system. Common signs and symptoms include loss of subcutaneous fat tissue, orthostatic hypotension, bradycardia (choice A), impaired menstrual function, hair loss, and hypothermia. ⚠ Elevated serum FSH (choice B) is incorrect. Amenorrhea in anorexia nervosa is caused by the hypothalamic-pituitary axis failure and is characterized by low levels of FSH. ⚠ Elevated serum beta hCG (choice C) would be seen in amenorrhea due to pregnancy or trophoblastic neoplasias. ⚠ Hypoalbuminemia (choice D) is incorrect. Albumin and protein levels are usually normal. ⚠ Shortened QT interval on ECG (choice E) is incorrect. Anorexia nervosa is associated with hypocalcemia and prolonged QT interval on ECG. ✅Key point: The diagnosis of anorexia nervosa includes refusal to maintain appropriate body weight, intense fear of becoming fat, undue influence of body weight or shape on self-evaluation, and amenorrhea. Anorexia nervosa is associated with bradycardia and orthostatic hypotension.

🇨🇦 MCCQE1,2 | #Case_45 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An 18-year-old female is brought to your department by her worried parents, because of her missed menstrual periods for the last 4 months and a very low weight. On questioning, the patient says that she has no appetite, denies any vomiting, and says that she is more interested in exercise to stay fit because she thinks she is “still super fat.” She denies laxative use. She reports having a boyfriend but she is not sexually active.Physical examination reveals a BMI of 15 kg/m2, dry skin, and cold hands. Which of the following is most likely to be present in this patient? a) Bradycardia b) Elevated serum FSH c) Elevated serum beta-hCG d) Hypoalbuminemia e) Shortened QT interval on ECG

🇨🇦 MCCQE1,2 | #Case_44 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation Third cranial nerve(oculomotor nerve) supplies all extraocular muscles (levator palpebrae, superior rectus, medial rectus, inferior rectus, and the inferior oblique) except the lateral rectus (supplied by the sixth cranial nerve) and the superior oblique (supplied by the fourth cranial nerve). Third cranial nerve also gives parasympathetic fibers to iris sphincter (constrictor) and the ciliary muscle of the eye. In a cross section of the nerve, the parasympathetic fibers are found closer to the surface of the nerve; therefore are almost always affected when a compressive lesion (e.g. berry aneurysm of the circle of Willis) is the cause for the third nerve palsy. The patient would have a dilated pupil in addition to eyelid ptosis and lateral deviation of the eye ball. In contrast, when third nerve palsy is the result of microvascular disease (e.g. diabetes, hypertension) these parasympathetic fibers may be spared and the patient may have eye lid ptosis and lateral deviation of the eye without pupillary dilation. Patient with a third nerve palsy may not complain of double vision (diplopia) if the eyelid ptosis is severe enough to cover the visual axis of the affected eye.Any patient presenting with eyelid ptosis, lateral deviation of the eye, and a dilated pupil should be investigated to exclude a compressive lesion. If the third cranial nerve palsy is caused by a Berry aneurysm of the circle of Willis, surgical intervention may not only relieve patient’s symptoms but could also be lifesaving. Among the choices given, MRA (a non-invasive test) is the investigation of choice to confirm a diagnosis of Berry aneurysm (choice B). ⚠ Serum glucose level (choice C) is useful, to confirm or exclude diabetes (i.e. microvascular disease), if the patient had eyelid ptosis and lateral deviation of the eye without pupillary involvement. ⚠ MRI of head (choice A) and CT scan of head (choice E) may not be sensitive enough to detect a small Berry aneurysm unless an intravenous contrast agent is used. ⚠ A lumbar puncture (choice D) should not be performed prior to neuroimaging in a patient suspected of having an intracranial lesion as it may lead to either trans-tentorial or uncal herniation and acute neurological deterioration. ✅Key point: In a patient presenting with eyelid ptosis, lateral deviation of eye (with or without double vision) and a dilated pupil the possibility of a Berry aneurysm of the circle of Willis impinging on the third cranial nerve must be considered. MRA of head is the investigation of choice under such circumstances.

🇨🇦 MCCQE1,2 | #Case_44 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 40-year-old man presents to the emergency department with acute onset pain and inability to open his right eye.On examination you find, on his right eye, there is complete eyelid ptosis, lateral deviation of the eye, and a dilated pupil, which does not react to light. Which investigation is most useful for confirming or excluding a diagnosis that would require an urgent intervention in this patient? a) Magnetic Resonance Imaging (MRI) of head b) Magnetic Resonance Angiogram (MRA) of head c) Serum glucose level d) Lumbar puncture e) Computed Tomography (CT) scan of the head

🇨🇦 MCCQE1,2 | #Case_43 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation Clinical trials support the treatment of systolic hypertension in the older person with a systolic blood pressure of at least 150 mm Hg. Systolic hypertension is defined as systolic blood pressure of at least 140 mm Hg and a diastolic blood pressure of less than 90 mm Hg. The studies most strongly support the use of thiazide diuretics and long-acting calcium channel blockers as first-line therapy. ⚠ Alpha-blockers are not recommended. ⚠ ACE inhibitors, beta-blockers, and angiotensin receptor blockers are used when certain compelling indications are present, e.g. in a patient with diabetes or who has had a myocardial infarction.

🇨🇦 MCCQE1,2 | #Case_43 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 An 83-year-old female presents to your office as a new patient. She recently moved to the area to be closer to her family. A history reveals that she has been in excellent health, has no complaints, and is on no medication except occasional acetaminophen for knee pain. She has never been in hospital and has not had any operations. She says that she feels well.The examination is normal, with expected age-related changes, except that her blood pressure on three different readings averages 174/70 mm Hg. These readings are confirmed on a subsequent follow-up visit.In addition to lifestyle changes, which one of the following would be most appropriate for the initial management of this patient's hypertension? a) An alpha-blocker b) An ACE inhibitor c) A beta-blocker d) An angiotensin receptor blocker e) A thiazide diuretic

🇨🇦 MCCQE1,2 | #Case_42 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ A 🔎 Explanation Trichinosis is infection with Trichinella spiralis or related Trichinella species. The usual incubation period of trichinellosis is 8-15 days. Trichinellosis may progress from an enteric (ie, intestinal) phase to a parenteral (ie, invasive) phase to a period of convalescence. The intestinal phase usually causes symptoms in the first week of illness: diarrhea, constipation, anorexia, and diffuse weakness, nausea, vomiting, and diarrhea, dyspnea may occur with exertion, abdominal discomfort and cramps may occur.The invasive phase corresponds to the migration of the larvae from the intestine to the circulatory system and eventually to the striated muscles. This phase is associated with a higher rate of symptoms than the intestinal stage. The duration varies from weeks to months. Severe myalgia develops in 89% of patients. The central nervous system is involved in 10%-24% of patients, with a mortality rate of 50%. Approximately 52% of patients present with headaches. Other symptoms include deafness, ocular disturbances, weakness, and monoparesis. Cardiac system involvement occurs during the third week of infection. Death may result from congestive heart failure and/or arrhythmias.There is no definitively positive laboratory test. CBC reveals eosinophilia. Creatine phosphokinase and lactic dehydrogenase levels are elevated in 90% of patients once the muscle invasion phase begins. CK levels are elevated. Urinalysis may reveal myoglobinuria. Plain radiographs of the extremities may show calcified densities in the muscles. Radiographs do not help evaluate acute infestation.CT scanning may be helpful in patients demonstrating neurologic symptoms.A muscle biopsy is the definitive diagnostic test. Larvae are found free or encapsulated, depending on the species of Trichinella causing the infection

🇨🇦 MCCQE1,2 | #Case_42 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 47-year-old patient comes in with a complaint of severe muscle pain. His symptoms have been present for two weeks now. His medical records disclose another visit for acute febrile diarrhea and abdominal cramps, from 4 weeks ago following his barbeque birthday party. He recovered well following appropriate supportive therapy.Today, on physical exam he shows signs of muscle weakness and tenderness. Blood work reveals eosinophilia, elevated creatine phosphokinase and lactic dehydrogenase levels.What is considered a definitive diagnostic test for the most likely diagnosis in this patient? a) Muscle biopsy b) Stool culture c) Stool gram stain d) Stool ova and parasites e) Abdominal CT scan

🇨🇦 MCCQE1,2 | #Case_41 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ B 🔎 Explanation The Papanicolaou smear is a screening test for precancerous cells. Any cervical dysplasia (formerly cervical intraepithelial neoplasia IIII, now low-grade and high-grade squamous intraepithelial lesion) necessitates colposcopy for definitive diagnosis. The diaphragm has not been associated with abnormal Pap smears, so changing the method of contraception would not be of any use. Conization of the cervix is always preceded by a colposcopy, and is indicated for unsatisfactory colposcopy, inconsistency of colposcopic findings with Pap smear findings, an endocervical curettage with abnormal cells, or a lesion on colposcopy extending into the endocervix. Reassurance and repeating the Pap smear in three months can be used for ASCUS (atypical squamous cells of undetermined significance); two serial ASCUS Pap smears necessitate colposcopy.

🇨🇦 MCCQE1,2 | #Case_41 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 At a routine physical examination, the Pap smear of a 27-year-old woman shows evidence of marked inflammation suggestive of moderate dysplasia (HGSIL). Her last Pap smear 2 years ago was normal. Pelvic examination today is normal. She has never been pregnant and her menstrual periods are regular. She has been in a stable relationship with the same man for 3 years and she uses a diaphragm with spermicidal jelly for contraception. The best next step is to: a) Advise the patient that her partner should use condoms for contraception and repeat the Pap smear in 3 months b) Do colposcopic examination of the cervix after application of 5% acetic acid solution c) Do conization of the cervix d) Reassure the patient and repeat the Pap smear in 3 months e) Treat the patient with metronidazole for 2 weeks and repeat the Pap smear in 3 months

🇨🇦 MCCQE1,2 | #Case_40 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ D 🔎 Explanation The neurological symptoms described in this patient of difficulty speaking and clumsiness with the hands combined with the findings of spasticity at the knees, the Kayser-Fleischer ring noted on slit lamp examination, and the abnormal liver function tests all point to a diagnosis of Wilson disease. It is an autosomal recessive inheritance disease of the copper metabolism characterized by excessive deposition of copper in the liver, brain, and other tissues.Out of the choices given, urinary copper excretion (choice D) would be the best way to confirm it. In untreated patients, the 24-hour urinary excretion of copper reflects the amount of non-ceruloplasmin-bound copper in the circulation. Normally urinary copper excretion should not exceed 40 microgram/day but in patients with Wilson disease urinary copper excretion is above 100 microgram/day. Chelating agents such as D -penicillamine are therefore prescribed to promote 24-hour excretion of approximately 2 mg of copper in the urine, to induce a negative copper balance. Regular measurement of the 24-hour urinary excretion of copper provides an important index of copper removal from the body. If the excretion level in a compliant patient decreases to less than 0.5 mg daily, the dose can be lowered. ⚠ Genetic testing (choice A) is impractical in Wilson disease due multiplicity of mutations involved; about 200 mutations of the ATP7B gene have been identified and currently there are no commercially available genetic testing. It is not the best follow up test. ⚠ Serum ceruloplasmin (choice B) is considered useful in patients with classic symptoms and the Kayser-Fleischer ring -It is the major carrier of copper in the blood but is also present as the protein without copper the copper. It is an important test to order as initial test and in a patient with neurological symptoms it can point to the diagnosis; however, it is also an acute phase reactant that can increase in infections, hepatic inflammations, pregnancy, and estrogen use. It is also decreased in malnutrition, nephrotic syndrome, malabsorption, and protein-losing enteropathy. Serum ceruloplasmin levels would be unreliable in this patient, who is on oral contraceptive pills and is also not the best follow up test to monitor therapy. ⚠ Abdominal CT scan (choice C) is uninformative with findings neither specific nor sensitive for Wilson disease and would not be helpful as follow up test in a patient receiving therapy. ⚠ Cerebrospinal fluid studies (choice E) would not be useful in monitoring chelation therapy for Wilson disease in this patient. ✅Key point: Wilson disease is an autosomal recessive inheritance disease of the copper metabolism characterized by excessive deposition of copper in the liver, brain, and other tissues. Wilson disease is treated with D-penicillamine, a copper chelating agent and the best test to monitor therapy is urinary copper excretion.

🇨🇦 MCCQE1,2 | #Case_40 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 20-year-old female presents to your department with difficulty speaking, excessive salivation, and clumsiness with the hands. She takes no medications except oral contraceptive pills. Family history is significant for a paternal uncle who had a similar condition and died at the age of 48.Physical examination reveals mild spasticity at the knees. Slit lamp examination shows a hyperpigmented ring around the iris. Liver function tests shows ALT: 108 U/L and AST: 97 U/L. After the patient's diagnosis is made and treatment is started, which of the following test would be the best to monitor therapy? a) Genetic testing b) Serum ceruloplasmin c) Abdominal CT scan d) Urinary copper excretion e) Cerebrospinal fluid studies

🇨🇦 MCCQE1,2 | #Case_39 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation This child’s symptoms of fever, headache, and the findings on physical examination of nuchal rigidity are suggestive of meningitis. The CSF studies with elevated neutrophil, increased protein, and decreased glucose point to bacterial meningitis. Children who are not properly immunized are particularly at risk. Bacterial meningitis can have serious sequelae even after appropriate treatment. Sensorineural hearing loss (choice C) is noted in 20% to 30% of Hemophilus influenza meningitis survivors. Audiologic assessments are recommended in these patients in 4 to 6 weeks after antibiotic treatment clears the infection. There are other possible complications such as hydrocephalus, cortical blindness, epilepsy, behavioral changes, motor coordination, and intellectual disability; however, the most common complication that should be assessed 6 weeks after treatment is hearing loss. ⚠ Subdural effusions (choice A) are asymptomatic complications that generally resolve without neurological sequelae. ⚠ Rheumatic heart disease (choice B) occurs as a complication of group A Streptococcus pharyngitis. It is unlikely to be the cause of meningitis in children of this age. The most common causes are Pneumococcus pneumonia, Meningococcal meningitis, and Hemophilus influenza. ⚠ Cortical blindness (choice D) is a rare complication of meningitis. It is far less common than hearing loss. ⚠ Post-infection glomerulonephritis (choice E) is not known to be a complication of the major bacteria associated with meningitis in children of this age. It can occur in children with group A streptococcus. ✅Key point: Bacterial meningitis is characterized by elevated neutrophil count, elevated protein, and decreased glucose in the CSF. Neurologic complications are common and the most common neurologic sequelae is sensorineural hearing loss and children should have audiologic assessment 4 to 6 weeks after treatment.

🇨🇦 MCCQE1,2 | #Case_39 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 A 5-year-old is brought to your department because of fever and headaches. He has had these symptoms for the last 48 hours and initially parents gave him Tylenol but he seems to be getting worse. The child’s immunization scheduled was not properly followed. His vital signs are: temperature 39.9°C, blood pressure 105/65 mmHg, pulse 100 bpm, and respirations 19/min. On physical examination he has no petechial rashes, his skin is warm, and nuchal rigidity is noted. CSF studies reveal elevated neutrophil count, elevated protein, and decreased glucose. Which of the following is the most common complication to be evaluated on his 6-week-treatment follow-up appointment? a) Subdural effusions b) Rheumatic heart disease c) Hearing loss d) Cortical blindness e) Postinfection glomerulonephritis

🇨🇦 MCCQE1,2 | #Case_38 | #answer 〰〰〰〰〰〰〰〰〰〰〰〰〰〰 ✅ C 🔎 Explanation Evaluation guidelines for solitary pulmonary nodule are based on nodule size and patient’s risk factors for cancer. Nodule diameter of 8mm or more, ‘ground glass’ opacity, irregular borders and doubling of size in one month to one year, are pointers to malignancy. History of smoking, old age, and extra-pulmonary malignancy are considered as risk factor for cancer.History of smoking and nodule of more than 8mm in the case described in the stem, indicate high probability of malignancy. Hence, biopsy of the lesion (choice C) is the most appropriate measure for accurate diagnosis.Most solitary pulmonary nodules are benign lesions, such as infectious granulomas and hamartomas. Malignant lesions include lung cancer, carcinoid tumor or metastasis. Survival rates of lung cancer are very low but early diagnosis can improve prognosis. ⚠Solitary nodule smaller than 8mm on a CT scan, in a person with high risk for malignancy, can be followed by repeat CT scan at 3-6 months, (choice A and B) and again at 12 and 24 months if the lesion remains stable. This is not relevant to the case described as the lesion size is 20mm. Solitary nodule smaller than 8mm on a CT scan in a person with low risk of malignancy, can be followed by repeat CT scan at 6-12 months. If there is no change in size at 12 months, no further follow up is indicated. ⚠ Positive Mantoux test (choice D) is a pointer to the diagnosis of tuberculosis but it does not rule out the possibility of neoplastic lung lesion. ⚠ Chest MRI (choice E) is indicated when it is not possible to do CT chest for reasons such as contrast allergy or renal insufficiency. ✅Key point: Any patient with evidence of large pulmonary nodule or nodule with notable growth during follow-up should undergo biopsy for diagnosis.