🇨🇦 MCCQE1,2 | #Case_284
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A 43-year-old chronically mentally ill man was admitted to the medical floor for ketoacidosis. His previously prescribed antipsychotic haloperidol was stopped and not restarted when he was transferred to an extended care facility several weeks later. A routine follow-up examination by his primary care physician finds the patient with tic-like movements of his face and tongue and lip smacking. Based on this information, what is the most likely diagnosis?

a) Diabetic neuropathy
b) Tourette's disorder
c) Parkinson's disease
d) Akathisia
e) Tardive dyskinesia

🇨🇦 MCCQE1,2 | #Case_285
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A 49-year-old female who takes multiple medications has a chemistry profile as part of her routine monitoring. She is found to have an elevated calcium level. All other values on the profile are normal, and the patient is not currently symptomatic. Follow-up testing reveals a serum calcium level of 2.8 mmol/L and a parathyroid hormone level of 80 pg/mL (N 10-65). Which one of the following should be discontinued for 3 months before repeat laboratory evaluation and treatment?

a) Lithium
b) Furosemide
c) Raloxifene
d) Calcium carbonate
e) Vitamin D

🇨🇦 MCCQE1,2 | #Case_285 | #answer
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✅ A

🔎 Explanation

Lithium therapy can elevate calcium levels by elevating parathyroid hormone secretion. This duplicates the laboratory findings seen with mild primary hyperparathyroidism. If possible, lithium should be discontinued for 3 months before reevaluation. This is most important for avoiding unnecessary parathyroid surgery. Vitamin D and calcium supplementation could contribute to hypercalcemia in rare instances, but they would not cause elevation of parathyroid hormone. Raloxifene has actually been shown to mildly reduce elevated calcium levels, and furosemide is used with saline infusions to lower significantly elevated calcium levels.

🇨🇦 MCCQE1,2 | #Case_286
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A 45-year-old woman is brought to the Emergency Department after she fainted in a supermarket. After evaluation the patient's glucose is found to be 2.5 mmol/l. Which one of the following criteria is most in favor of the diagnosis of hypoglycemic disorder?

a) Cushing's triad
b) Whipple's triad
c) Samter's triad
d) Virchow's triad
e) Beck's triad

🇨🇦 MCCQE1,2 | #Case_286 | #answer
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✅ B

🔎 Explanation

Hypoglycemia unrelated to exogenous insulin therapy is an uncommon clinical syndrome characterized by low plasma glucose level, symptomatic sympathetic nervous system stimulation, and CNS dysfunction. Many drugs and disorders
cause it. A diagnosis of hypoglycemic disorder can be suggested by the Whipple's triad (choice B). Essential conditions of this triad are:

▪ Symptoms are known or likely to be caused by hypoglycemia
▪ A low plasma glucose measured at the time of the symptoms
▪ Relief of symptoms when the glucose is raised to normal

⚠ Cushing's triad (choice A) is characterized by bradycardia, bradypnea, and hypertension, which are often associated with head injuries.

⚠ Samter's triad (choice C) is seen in aspirin-induced asthma and is characterized by aspirin sensitivity, nasal polyps,and asthma.

⚠ Virchow's triad (choice D) is composed of stasis, hypercoagulability, and vessel injury. It is associated with venous thrombosis.

⚠ Beck's triad (choice E) is characterized by muffled heart sound, distended neck veins, and hypotension; it is diagnostic of cardiac tamponade

🇨🇦 MCCQE1,2 | #Case_287
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A 20-year-old man returns to the office for a follow up visit 4 weeks after being diagnosed with mononucleosis. At his
initial visit, he had a sore throat, nausea and a temperature of 39.4°C (103°F). Physical examination at that time showed pharyngitis, submandibular and posterior cervical lymphadenitis, and splenomegaly. Complete blood count (CBC) done at that time showed a leukocyte count of 18,000 with an elevated number of monocytes, and a Monospot test was positive. He asks you, "When can I play again?"
Which of the following is the most appropriate response to the patient regarding when he may return to contact sports?

a) Next season
b) When a Monospot test is negative
c) When he is no longer symptomatic
d) When his CBC is normal
e) When his physical examination is normal

🇨🇦 MCCQE1,2 | #Case_287 | #answer
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✅ E

🔎 Explanation

The concern with infectious mononucleosis, a disease caused by the Epstein-Barr virus, is for splenomegaly. The issue of contact sports after a course of mono relates solely to when the risk of splenic injury has declined. No treatment other than rest is needed in the vast majority of cases. The spleen, being part of the lymphatic system, will generally regress in size in accord with the decline in physical signs, such as swollen lymph nodes. Waiting until next season is too long and, although likely to allow a large margin of safety, will unnecessarily keep the student from playing his sport. The Monospot test is the diagnostic test that detects the antibody generated against the EBV (heterophil antibody) in the blood of the patient. Since the immune response is last quite long, a negative Monospot test may take years to become present. Waiting for the patient to be symptom free is also too long as fatigue may persist for months after the resolution of the lymph node enlargement. The CBC may return to normal well before the lymph nodes have regressed in size.

🇨🇦 MCCQE1,2 | #Case_288
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During rounds, you notice a new rash on a full-term 2-day-old white female. It consists of 1 mm pustules surrounded by a flat area of erythema, and is located on the face, trunk, and upper arms. An examination is otherwise normal, and she does not appear ill. Which one of the following is the most likely diagnosis?

a) Erythema toxicum neonatorum
b) Transient neonatal pustular melanosis
c) Acne neonatorum
d) Systemic herpes simplex
e) Staphylococcus aureus sepsis

🇨🇦 MCCQE1,2 | #Case_288 | #answer
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✅ A

🔎 Explanation

This infant has the typical “flea-bitten” rash of erythema toxicum neonatorum (ETN). ETN is a benign self-limited eruption occurring primarily in healthy newborns in the early neonatal period. Erythema toxicum neonatorum is characterized by macular erythema, papules, vesicles, and pustules, and it resolves without permanent sequelae.

⚠ Transient neonatal pustular melanosis (choice B) is most common in black newborns, and the lesions lack the surrounding erythema typical of ETN.

⚠ Acne neonatorum (choice C) is associated with closed comedones, mostly on the face.

⚠ As the infant described is not ill, infectious etiologies (choice D and choice E) are unlikely

🇨🇦 MCCQE1,2 | #Case_289
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A 29-year-old male presents to your department because of fatigue. He has a long history of beta-thalassemia major and has received multiple blood transfusions throughout his life. Physical examination reveals gray skin and lung crepitations. Laboratory tests show hemoglobin of 81 g/L. What is the most appropriate next step in management?

a. Blood transfusion
b. Hydroxyurea
c. Therapeutic phlebotomy
d. Erythropoietin
e. Vitamin C supplementation

🇨🇦 MCCQE1,2 | #Case_289 | #answer
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✅ B

🔎 Explanation

This patient has a long history of beta -thalassemia major and the fatigue is most likely caused by anemia. The findings on physical examination of gray skin and lung crepitations are most likely manifestations of transfusion-induced hemosiderosis. Given the patient's iron overload, at this point an alternative therapy should be considered for his anemia, such as manipulation of globin gene expression. Hydroxyurea (choice B) increases the production and concentration of fetal hemoglobin (hemoglobin F), which reduces transfusion requirements.

⚠ Blood transfusion {choice A) is incorrect. At this point with the patient's blood transfusion induced hemosiderosis the most appropriate next step is to give hydroxyurea first to decrease the need of frequent transfusions.

⚠ Therapeutic phlebotomy {choice B) is appropriate in patients with hemochromatosis associated iron overload but is inappropriate in anemic patients with transfusion-induced iron overload. In these patients the primary goal of iron chelation therapy is to prevent the accumulation of iron reaching harmful levels by matching iron intake from blood transfusion, with iron excreted by iron chelation.

⚠ Erythropoietin (choice D) is incorrect because the problem with beta-thalassemia is not with the production of red blood cells but with the defective hemoglobi n.

⚠ Vitamin C supplementation {choice E) is considered useful in iron chelation in patients receiving deferoxamine infusion. But by itself, it is not sufficiently effective and large doses of vitamin C without concomitant infusion of deferoxamine have been reported to cause arrhythmias

🇨🇦 MCCQE1,2 | #Case_290
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A 54-year-old woman is admitted to emergency department with acute kidney injury. Other than body temperature of 37.9°C, vital signs are stable and the rest of physical examination is also normal. Urinalysis reveals normal pH, low specific gravity and white cell casts but is negative for white blood cells, red blood cells and protein. 24hour urinary protein shows low molecular weight proteinuria of 1.4g. Complete blood count is normal. Which of the following pieces of history might support the diagnosis suggested by the clinical picture and results of investigations?

a. History of diabetes mellitus
b. Having had sore throat two weeks ago
c. Having had impetigo four weeks ago
d. Having chronic joint pain .
e. Having had self-limited diarrhea three weeks ago

🇨🇦 MCCQE1,2 | #Case_290 | #answer
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✅ D

🔎 Explanation

Acute kidney injury associated with fever, urine with low specific gravity and low molecular weight proteinuria is suggestive of acute tubulointerstitial nephritis, which is commonly caused by analgesic nephropathy. Patients with chronic joint pain (choice D) are likely to try and use specific medications, mixtures or combinations of analgesic medications that might cause interstitial nephritis. Analgesic nephropathy could be either acute or chronic and the acute form may develop months after exposure to the medication. Some patients may have fever and skin rash at diagnosis. Presence of eosinophils in urine supports the diagnosis but absence of these cells does not exclude the diagnosis.

⚠ Diabetes mellitus (choice A) causes glomerular rather than tubular disease. Thus, this disease usually presents as microalbuminuria with negative standard dipstick {as in our patient's urinalysis) and 24hour protein between 30 - 300 mg/day. As its name implies, the major protein in urine of patients with microalbuminuria is albumin and not low molecular weight protein as in tubular disease.

⚠ Having had sore throat two weeks ago (choice B) or impetigo four weeks ago (choice C) would suggest glomerular disease as a cause of acute kidney injury. However, the clinical picture (fever) and the results of lab investigations (absence of hematuria, low molecular weight proteinuria, low urine specific gravity) suggest tubulointerstitial nephritis, instead.

⚠ Having had self-limited diarrhea three weeks ago (choice E) might suggest a diagnosis of hemolytic
uremic syndrome in which rena l failure and anuria may be preceded by history of diarrhea. This disorder is more common in children and in addition to red cells and red cell casts in urine, complete blood count of these patients usually reveals thrombocytopenia and features of microangipathic
hemolytic anemia.

🔖 Key point:

There is no specific test that is diagnostic of tubulointerstitial nephritis, which is most commonly drug-induced (70-75%). Therefore, obtaining a detailed history is of paramount importance for diagnosis of this disease

🇨🇦 MCCQE1,2 | #Case_291
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A 69-year-old female sees you for an annual examination. She asks you to look at her toes, and you note a fungal infection in five toenails. She says the condition is painful and limits her ability to complete her morning walks. She asks for treatment that will allow her to resume her daily walks as soon as possible. Her only other medical problem is allergic rhinitis which is well controlled. Which one of the following would be the most appropriate treatment for this patient?

a. Oral griseofulvin ultramicrosize (Gris-PEG) daily for 12 weeks
b. Oral terbinafine (Lamisil) daily for 12 weeks
c. Topical terbinafine (Lamisil An daily for 12 weeks
d. Topical ciclopirox (Pen lac Nail Lacquer) daily for 12 weeks
e. Toenail removal

🇨🇦 MCCQE1,2 | #Case_291 | #answer
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✅ B

🔎 Explanation

Continuous therapy with oral terbinafine for 12 weeks has the highest cure rate and best long-term resolution rate of the therapies listed. Other agents and pulsed dosing regimens have lower cure rates. Topical creams are not appropriate for onychomycosis because the infection resides in the cell of the toenail. Antifungal nail lacquers have a lower cure rate than systemic therapy and should be used only when oral agents would not be safe. Toenail removal is reserved for patients with an isolated infected nail or in cases involving a dermatophytoma

🧩 Medical Mnemonics


⏳ A 65-year-old man in the hospital receiving spinal anesthesia for crush injuries to his lower extremities starts to notice labored breathing. He is afebrile but develops nausea and vomiting, and last had a bowel movement yesterday. His abdomen is distended and tympanic to percussion, although there are scattered bowel sounds. A plain upright abdominal film reveals a largely dilated colon extending from the cecum to the splenic flexure. Water-soluble enema fails to reveal mechanical obstruction.


🗓 February 13, 2020

#case_of_the_week
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©Medical Mnemonics

🇨🇦 MCCQE1,2 | #Case_292
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A 45-year-old male was recently diagnosed with type 2 diabetes mellitus. He presents to your office today to begin oral antihyperglycemic therapy. Results of a fasting serum metabolic panel include the following:
Laboratory Findings:
Sodium: 136 mmoi/L (N 136-145)
Potassium: 3.7 mmoi/L (N 3.5-5.1)
Chloride: 102 mmoi/L (N 98-1 07)
BUN: 15 mg/dL (N 7-18)
Creatinine: 1.7 mg/dL (N 0.6-1.3)
Glucose: 183 mg/dL

Which one of tile following medications would be contraindicated in this patient?

a) Glipizide (Giucotrol)
b) Acarbose(Precose)
c) Metformin (Giucophage)
d) Pioglitazone (Actos)

🇨🇦 MCCQE1,2 | #Case_292 | #answer
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✅ C

🔎 Explanation

Maintaining good blood glucose control is important for preventing the microvascular complications of diabetes mellitus. A number of oral
antihyperglycemic agents are available, but each drug class has unique adverse effects that affect their appropriateness for individual patients. In this case, the patient has evidence of renal impairment (serum creatinine 1 .5 mg/dl for men and 1 .4 mg/dl for women). This leads to an increased risk of lactic acidosis when a biguanide such as metformin is used. Other contraindications to biguanide use include hepatic dysfunction, congestive heart failure, metabolic acidosis, dehydration, and alcoholism. The sulfonylureas include chlorpropamide (1st generation) and glipizide (2nd generation). They are associated with weight gain and hypoglycemia. a-Glucosidase inhibitors (e.g., acarbose) are less effective than other drug classes as monotherapy and can be associated with gastrointestinal side effects. Thiazolidinediones (e.g., pioglitazone) are associated with weight gain, edema, and potential liver injury

🇨🇦 MCCQE1,2 | #Case_293
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A 45-year-old female with rheumatoid arthritis has a hemoglobin level of 95 giL. Her arthritis is well controlled with methotrexate (Trexall). Further evaluation reveals the following:

Hematocrit: 29.0%
Mean corpuscular volume: 78 fl Platelets: 230 x 10^9/L
WBC: 6.9 X 10^9/l
Differential: normal
Serum iron: 6 micromol/L
Total iron binding capacity: 150 micromol/L
Iron saturation: 10%
Serum ferritin: 7 microgram/L
Reticulocyte count: 8x10^9/L
Stool guaiac: negative x 3

Which one of the following would be the most appropriate next step?

a) Evaluation for a source of blood loss
b) Hemoglobin electrophoresis to screen for thalassemia
c) Stopping the methotrexate and beginning an alternative treatment for rheumatoid arthritis
d) No further evaluation at this point
e) Initiate iron supplement pills

🇨🇦 MCCQE1,2 | #Case_293 | #answer
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✅ E

🔎 Explanation

In iron deficiency anemia, total-body iron levels are low. leading to hypochromia and microcytosis, low iron levels. increased transferrin levels. and reduced ferritin levels. This patient's anemia is most likely multifactorial, with anemia of chronic disease and drug effects playing a role. However. she also has iron deficiency, and oral ferrous sulphate treatment should be initiated with regular testing to monitor treatment response.

⚠️ In males and in postmenopausal women, a Gl work-up (choice A) is always warranted.

⚠️ With thalassemia (choice B), marked microcytosis is seen, and with hemolysis of any standing, slight macrocytosis and an increased reticulocyte count would be expected.

⚠️ Methotrexate has rarely caused serious side effects. In high doses. it may cause some Gl bleeding when used at the same time as non steroidal anti-inflammatory drugs. In this case. it would present with blood in stool or urine. This patient's findings are negative for blood in stool. Stopping the methotrexate and beginning an alternative treatment for rheumatoid arthritis (choice C) would be unnecessary until evaluation for a blood loss source is identified.

⚠️ No further evaluation (choice D) is incorrect. This patient's anemia requires further evaluation.