CASE FILES #4

Question 1

A 68 years old patient with history of arrhythmia is admitted to the emergency room for sedation and ataxia. He had also a brief episode of seizures. Drug toxicity is suspected. He has been on an anti-arrhythmic for the past few months. Following electrophysiological assessment the duration of the action potential was shown to be reduced due to the effect of the prescribed anti-arrhythmic. Which of the following is the normal cardiac depolarization pathway leading to the generation of an action potential?

SA Node  AV Node  Atria Bundle of His  Purkinje Fiber  Ventricle
SA Node  Atria  AV Node Ventricle  Bundle of His  Purkinje Fiber
SA Node  Atria  AV Node Bundle of His  Purkinje Fiber  Ventricle
SA Node  Atria  AV Node Purkinje Fiber Bundle of His  Ventricle
SA Node  AV Node  Bundle of His Atria  Purkinje Fiber  Ventricle

Answer 1

SA Node – Atria – AV Node– Purkinje Fiber–Bundle of His – Ventricle

Question 2

Which of the following statements best describes the mechanism of the antiarrhythmic prescribed?

It primarily increases the effective refractory period
It primarily prolongs the duration of phase 0
It primarily blocks sodium channels
It primarily blocks potassium channels
It primarily blocks beta adrenergic receptors

Answer 2

It primarily blocks sodium channels

Question 3

Which of the following antiarrhythmic is the likely offending drug?

Quinidine 
Flecainide 
Amiodarone
Phenytoin
Esmolol

Answer 3

Phenytoin

Question 4

The patient was later switched to another antiarrhythmic. The newly prescribed drug is a class I antiarrhythmic and induces Lupus like symptoms. Which of the following drugs is the newly prescribed antiarrhythmic?

Disopyramide
Phenytoin
Procainamide
Lidocaine
Flecainide

Answer 4

Procainamide

Question 5

A 68 years old patient with rheumatoid arthritis and chronic heart disease is on amiodarone for the treatment of ventricular tachycardia. She presents to the emergency room complaining of increased heartbeat, dizziness and ataxia. Her symptoms are consistent with amiodarone toxicity.

Question 1: Amiodarone displays all of the following effects, EXCEPT:

Class I antiarrhythmic effect
Class II antiarrhythmic effect
Class III antiarrhythmic effect
Class IV antiarrhythmic effect
Class V antiarrhythmic effect

Answer 5

Class V antiarrhythmic effect

Question 6

If this patient is found to have an overdose of amiodarone which of the following substances could be used to reverse its toxicity?

Acetylcysteine
Leucovorin
Activated charcoal
Naloxone
Thiamine

Answer 6

Activated charcoal

Question 7

A 55-year-old is admitted to the emergency department with irregular heart rate. The ECG shows an inferior myocardial infraction and atrial fibrillation. Diltiazem is prescribed. All of the following statements describe the action of Diltiazem, EXCEPT:

Blocks competitively Na+/K+ATPase channels
Binds to open depolarized calcium channels preventing repolarization
Slows AV node conduction
Belongs to class IV antiarrhythmics
Has negative inotropic effect

Answer 7

Blocks competitively Na+/K+ATPase channels

Question 8

A 35-year-old female visits your clinic complaining of fatigue and shortness of breath. During physical examination, you noticed that she is pale and her nails are brittle. You order a CBC, which shows the following: Hemoglobin 10 g/dL (12.1-15.1g/dL); hematocrit 33.5% (N: 36.1 – 44.3%); MCV 74 femtoliter (N: 80-100 femtoliter); WBC 6,600 cells/mcL (N: 4,500 – 10,000 cells/mcL).
Question 1: Which of the following is the most likely diagnosis?

She has microcytic anemia, probably due iron deficiency anemia
She has microcytic anemia probably due to blood loss
She has megaloblastic anemia, probably due to folate deficiency
She has megaloblastic anemia, probably due to B12 deficiency
She has a hemolytic anemia probably due to G6PD deficiency

Answer 8

She has microcytic anemia, probably due iron deficiency anemia

Question 9

Which of the following drugs would be an appropriate treatment option?

Pyridoxine
Iron dextran
Folic acid
Vitamin B12
Nascobal

Answer 9

Iron dextran

Question 10

A 38-year-old male patient is scheduled for surgery for the removal of a localized abdominal tumor. He has pheochromoctytoma and his blood pressure is 190/120 mmHg.  His hematocrit is 48%. His liver and kidney functions are normal. Which of the following anesthetic should be avoided in this patient?  

Isoflurane
Enflurane
Sevoflurane
Halothane
Desflurane

Answer 10

Halothane

Question 11

A 62 years old with two years history of recurrent atrial fibrillation is being treated with flecainide. Atrial fibrillation is an irregular heartbeat that can lead to blood clots, stroke, heart failure and other heart-related complications. An estimated 2.7 million Americans are living with AFib. Which of the following ECG tracings represents Atrial Fibrillation

Answer 11

C

Question 12

A patient being treated for Congestive Heart Failure (CHF) caused by viral myopathy has been scheduled for heart transplant surgery. He is on cyclosporine, prednisone and azathioprine to reduce the likelihood of transplant rejection. Which of the following statements best describes the mechanism of cyclosporine?

Binds to immunophilin FKBP-12 which inhibits calcineurin a calcium-dependent phosphatase
Suppresses cell-mediated immunity by binding to cyclophilin and inhibiting calcineurin
Binds to FKBP-12 which inhibits mTOR a serine-threonine kinase
Converted to 6-mercaptopurine and then to thioinosinic acid nucleotide triphosphate
Reversible uncompetitive inhibitor of inosine monophosphate dehydrogenase

Answer 12

Suppresses cell-mediated immunity by binding to cyclophilin and inhibiting calcineurin

Question 13

A 40-year-old woman is scheduled to receive one of the following combinations of drugs for general anesthesia: nitrous oxide/halothane OR nitrous oxide/isoflurane. In order to determine which combination has a better safety profile, you decide to run a quick Evidence Based Medicine (EBM) search. Which of the following sets of adverse effects represents an accurate comparison of halothane (H) and isoflurane (I)?

Answer 13

E

Question 14

Pills containing iron are commonly used to treat anemia. Iron poisoning usually causes symptoms within 6 hours of overdose. The symptoms of iron poisoning typically occur in 5 stages. Stage 1 is characterized by vomiting, diarrhea, abdominal pain, irritability, and drowsiness. In case of iron overdose, which of the substances is an effective antidote?

Atropine
Flumazenil
Ascorbic acid
Mesna
Deferoxamine

Answer 14

Deferoxamine

Question 15

An otherwise healthy 70-year-old man receives 12 units of packed red blood cells for persistent bleeding during a suprapubic prostatectomy. Hemoglobin concentration is 11.5 g/dL (N: 13.8 – 17.2g/dL); platelet count is 230,000/mcL (N: 150,000 – 400,000/mcL); plasma fibrinogen and plasminogen levels are within normal values; prothrombin time (PT) is 12 sec (N:11 – 13.5 sec); partial thromboplastin time (aPTT) is 52 sec (N:30 – 40 sec); transferrin saturation 33% (N: 20 – 50%); iron 88 mcg/dL (N: 60 -170 mcg/dL);TIBC 300 (N: 250 – 450 mcg/dL); MCV 87 (N: 80 – 100 femtoliter).

Question 1: Based on the results, which of the following is the likely diagnosis?
Anemia due to iron deficiencythis is liked to B12 and extrinsic factor(inmature redblood cells)
Pernicious anemia–
Hemolytic anemia– if the aPTT in in the normal range it could be C
Hemophilia—- intrinsic pathway. aPTT is an indicator of the ans.
Megaloblastic anemia

Answer 15

Hemophilia—- intrinsic pathway. aPTT is an indicator of the ans.

Question 16

Which of the following agents could be an appropriate therapeutic option in this patient?

Iron dextran
Cyanocobalamin
Folic acid
Tranexamic acid
Epoetin alpha

Answer 16

Folic acid

Question 17

Which of the following sets of side effects are associated with tacrolimus?

Nephrotoxicity, gingival hyperplasia, hyperglycemia
Nephrotoxicity, neurotoxicity, thrombocytopenia
Nephrotoxicity, neurotoxicity, hyperglycemia
Gingival hyperplasia, neurotoxicity, hyperglycemia
Thrombocytopenia, neurotoxicity, Gingival hyperplasia

Answer 17

Nephrotoxicity, neurotoxicity, hyperglycemia

Question 18

A 58-year-old man presents with a myocardial infarction; it is his first episode of ACS. Angioplasty and stenting are not possible because the cardiac lab is busy with other high-priority patients. Therefore, the administration of a thrombolytic drug is the only option. Which of the following statements best describes the most important determinant of the success of thrombolytic therapy in terms of salvaging viable cardiac muscle?

Administration of human plasminogen activator rather than one that is bacterial-derived
The location of the myocardial injury
Presence of collateral blood vessels to the infarct-related coronary artery

Blood pressure level at the time the MI is diagnosed

Time from onset of infarction to administration of the thrombolytic agent

Answer 18

Time from onset of infarction to administration of the thrombolytic agent

Question 19

A 19-year old male patient was transported by ambulance to the emergency department. His mother explains that he took a potentially lethal dose of zinc tablets in an apparent suicide attempt. Which of the following drugs would be an effective antidote to manage this severe zinc poisoning?

Phentolamine 
Pyridoxine 
Acetylcysteine 
Thiamine 
Penicillamine

Answer 19

Penicillamine

Question 20

A 20-year-old man presents to your office with persistent cough. He was later diagnosed with moderate allergic asthma. You prescribe an anti-IgE monoclonal antibody. Which of the following monoclonal antibodies was prescribed?

Infliximab
Trastuzumab 
Omalizumab 
Adalimumab
Muromonab  

Answer 20

Omalizumab

Question 21

A patient presents with severe abdominal pain and a burning sensation in the upper abdomen. Endoscopy reveals several benign ulcers in the mucosa of the stomach.

Q1: Which of the following drugs is most likely to provide the fastest and probably the briefest relief of the discomfort with just a single dose?

Aluminum hydroxide 
Sucralfate 
Cimetidine
Misoprostol
Omeprazole

Answer 21

Aluminum hydroxide

Question 22

A patient in the emergency department requires suturing of a deep laceration. To reduce discomfort you first infiltrate the surrounding area with lidocaine. Which of the following functions or sensations is most likely to disappear first as the drug’s effects build up, and the last to reappear as the drug’s effects wear off?

Autonomic efferent function 
Motor nerve activity 
Sensation of pain 
Sensation of pressure  
Sensation of heat

Answer 22

Sensation of pain

Question 23

Which of the following drugs is contraindicated in combination with heparin due high risk of excessive hemorrhage?

Alteplase 
Aspirin 
Clopidogrel 
Streptokinase 
Warfarin

Answer 23

Streptokinase

Question 24

Metoclopramide is an effective agent used to treat nausea and vomiting associated with conditions such as chemotherapy and migraines. All of the following statements concerning metoclopramide are correct, EXCEPT:

Prokinetic agent stimulating peristalsis
Agonist of dopamine D2 receptors
Antagonist of 5-HT3 receptors
Increases lower esophageal sphincter tone
Can induce galactorrhea, dystonia and tardive dyskinesia

Answer 24

Agonist of dopamine D2 receptors

Question 25

A 58-year old grocery store manager visits the clinic. He had recently been waking up in the middle of the night with abdominal pain several nights a week. He was also experiencing occasional discomfort in the middle of the afternoon. His physician prescribes sucralfate as initial treatment. Sucralfate is an cytoprotective agent indicated for the treatment of gastric and duodenal ulcers, and gastroesophageal reflux disease (GERD). All of the following statements describe sucralfate, EXCEPT:

Aluminum hydroxide – sulfated sucrose complex
Acts as a mechanical barrier blocking the diffusion of HCl in the gastrointestinal tract mucosa
Must be taken with food to enhance its polymerization and potency
Reduces ulcer healing time and prevents recurrence
Side effects are GI related

Answer 25

Must be taken with food to enhance its polymerization and potency

Question 26

A 23-year-old man presented with malaise, night sweats, loss of weight and intermittent fever dating from a flu-like illness 3 months previously. On examination, he had bilateral, cervical and axillary lymphadenopathy; the glands were 2-5cm in diameter, firm, rubbery, discrete and fairly mobile. His liver and spleen were not enlarged. A cervical lymph node was removed for histology. Tissue micrograph shows giant cells known as Reed-Sternberg cells that are characteristic of Hodgkin’s disease (figure below). A diagnosis of Hodgkin’s lymphoma was made. His physician initiates treatment with a monoclonal antibody proven effective in the treatment of the condition. The monoclonal antibody is labeled with the chemotherapeutic drug Monomethyl Auristatin E.
Which of the following monoclonal antibodies was prescribed?

Brentuximab vedotin
Ado-trastuzumab emtansine
Blinatumomab
Ibritumomab tiuxetan
Alemtuzumab

Answer 26

Brentuximab vedotin