Medical assessment and management of the surgical patient Flashcards
Which of the following infections has a DNA virus as its etiologic agent? A. Mononucleosis B. Scrofula C. AIDS D. Herpangina
<p>Answer: A
Rationale:
It is estimated that 79% of Mononucleosis from an Epstein - Barr virus (EBV) infection; 21 % from a cytomegalovirus (CMV) infection. Both are DNA viruses.
Scrofula (tuberculosis cervical lymphadenitis) is a secondary infection of the cervical lymph node chain, associated with active pulmonary tuberculosis (Mycobacterium tuberculosis) and results in a draining lesion. AIDS is transmitted by Human immunodeficiency virus (HIV) and is a RNA retrovirus. Patients present with opportunistic infections. Herpangina is a Coxsackie virus infection, and is characterized by vesicular eruptions on the fauces and palate. Coxsackie viruses are RNA viruses.
Reference:
Bergman, SA In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 243-278.
McKenna, SJ In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 456-467.
Hupp, JR In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 112-125.
Rubinovitch et al in Cohen & Powderly: Infectious Diseases, 2nd ed., Copyright © 2004 Elsevier, p 200.</p>
A patient who has had a splenectomy within the last 6 months is most susceptible to which of the following infectious agents? A. Treponema pallidum B. Haemophilus influenzae C. Pneumocystis carinii D. Mycobacterium tuberculosis
<p>Answer: B
Rationale:
Patients who have had a splenectomy are most commonly susceptible to infection by encapsulated bacteria. Haemophilus influenzae is the only bacteria listed which is encapsulated. Following splenectomy, it is recommended that patients be administered the Pneumnovax vaccine to provide active immunity to the encapsulated pneumococcus bacteria.
Reference:
McKenna, SJ In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 456-467
CDC, Morbidity & Mortality Weekly Report: Prevention of Pneumococcal Disease Recommendations of the Advisory Committee on Immunization Practices (ACIP) April 4, 1997 / Vol. 46 / No. RR-8</p>
<p>Which drug or drug class should be avoided if possible in patients with hypertrophic cardiomyopathy?
A. β- blockers
B. Angiotensin converting enzyme inhibitors
C. Calcium channel blocker
D. Diuretics</p>
<p>Answer: D
Rationale:
Dehydration in patients with this condition acts to increase the outflow tract pressure gradients from the heart and generate an increase in symptoms. This can be exacerbated as well with strenuous activity and result in sudden death. Dehydration and the use of diuretics should be avoided if possible so as not to alter this gradient. Digitalis, nitrates, vasodilators and β ñ adrenergic agonists are also to be avoided.
Beta-blockers are the mainstay of medical therapy for hypertrophic cardiomyopathy. Angina, dyspnea, and presyncope may all be improved with beta-blockers. Calcium channel blockers are an alternative therapy to beta blockers. ACE inhibitors are not typically used in the treatment of hypertrophic cardiomyopathy.
Reference:
Kasper, D Braunwald, E et al Harrison's Principles of Internal Medicine 16th ed., McGraw- Hill, New York, 2005 p1411.
Zipes: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005, Elsevier, Chapter 59, Hypertrophic Cardiomyopathy.</p>
<p>Which type of cardiomyopathy is most often associated with high outflow tract pressures? A. Restrictive B. Dilated C. Idiopathic D. Hypertrophic</p>
<p>Answer: D
Rationale:
Patients with hypertrophic cardiomyopathy are most frequently associated with having increased left ventricular outflow tract obstruction. This occurs in approximately 25% of these patients. It is usually related to narrowing of the subaortic area as sequelae of the apposition of the mitral valve leaflet in juxtaposition to the enlarged interventricular septum. Hypertrophic cardiomyopathy is an autosomal dominant inherited disease at least 50% of the time. There are sporadic forms of the disease due to spontaneous mutations.
Dilated cardiomyopathy is characterized by cardiac enlargement and impaired systolic function of one of both ventricles. Restrictive cardiomyopathy is the least common form in the western hemisphere. The hallmark feature is abnormal diastolic function. The ventricular walls are excessively rigid and impede ventricular filling. Systolic function is often not impaired. Both dilated and restrictive cardiomyopathy can be idiopathic in nature.
Reference:
Kasper, D Braunwald,E et al Harrison's Principles of Internal Medicine 16th ed., McGraw- Hill, New York, 2005 pp1409-1412.
Zipes: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed, 2005, Elsevier.</p>
<p>Caution should be given to administering local anesthetics containing vasoconstrictor to hypertensive patients treated with which medication? A. ACE inhibitors B. Non-selective beta blockers C. Calcium channel blockers D. Angiotensin receptor blockers</p>
<p>Answer: B
Rationale:
Treatment of hypertension with a non-selective beta blocker will affect both beta-1 and beta-2 receptors. Epinephrine or levonordefrin will normally cause sympathetic stimulation of both alpha and beta adrenergic receptors. Alpha-1 mediated vasoconstriction is unopposed with beta blockade and can result in severe hypertension and possible reflex bradycardia.
ACE inhibitors affect the renin-angiotensin pathway leading to decreased angiotensin II production. Angiotension II is a potent vasoconstrictor and therefore this reduces peripheral vasoconstriction and afterload and will decrease blood pressure. Ca channel blockers will lead to a decrease in the vasoconstriction of peripheral vasculature leading to a decrease in BP.
Reference:
Ganzberg, Local Anesthetics and Vasoconstrictors. Oral and Maxillofacial Surgery Clinics of North America, Volume 13, #1, p. 71, 2001.</p>
<p>The agent with the slowest onset of action when treating an acute.hypertensive crisis is: A. esmolol (Brevibloc). B. labetolol (Normodyne). C. sublingual nitroglycerin (Nitrostat). D. hydralazine (Apresoline).</p>
<p>Answer: D
Rationale:
Esmolol is a selective beta blocking agent against B1 receptors. The onset of action for IV esmolol is 2-10 minutes. Labetalol has an onset of 2-5 minutes. It is a B1 and B2 blocker, and also blocks alpha receptors. Onset for sublingual nitroglycerin is 2-5 minutes. Nitroglycerin causes vasodilation and arterial dilation. Hydralazine has an onset of 5-20 minutes. Hydralazine is a direct peripheral dilator, with prolonged duration of action.
Reference:
Dym, The Hypertensive Patient. Oral and Maxillofacial Surgery Clinics of North America, Volume 10, #3, p. 358, 1998.
Stoelting, Dierdorf, Anesthesia and Co-Existing Disease, 4th edition, p. 98, 2002.</p>
<p>A 56 year-old white male has been diagnosed with secondary hypertension associated with hyperaldosteronism. The laboratory finding consistent with this diagnosis is: A. hyperkalemia. B. hypokalemia. C. hypercalcemia. D. hypocalcemia.</p>
<p>Answer: B
Rationale:
An adrenal adenoma or hyperplastic adrenal gland increases secretion of aldosterone from the zona glomerulosa (outermost layer) of the gland. Primary aldosteronism produces secondary hypertension associated with hypokalemia and suppressed renin activity. Aldosterone causes potassium excretion and sodium resorption from the distal tubule and collecting duct, which leads to the hypokalemia and hypernatremia with increased extracellular fluid volume. Magnesium and chloride levels can also be reflexly altered. Changes in calcium levels are not typically observed.
Reference:
Stoelting, Dierdorf, Anesthesia and Co-Existing Disease, 4th edition, p. 94-95, 429-430, 2002.
Andreoli, et al, Cecil Essentials of Medicine, 5th edition, p.245-246, 572, 2001.</p>
<p>A 70 year-old male with a history of mitral stenosis presents complaining of longstanding fatigue, exertional dyspnea, and occasional chest pain. Clinically, he shows jugulovenous distension, peripheral edema, and hepatosplenomegaly. Additional clinical findings most consistent with this presentation are:
A. decreased pulmonary artery pressure by catheterization.
B. left ventricular hypertrophy by chest radiograph.
C. ECG findings of right axis deviation, peaked P waves in II, III, and AVF.
D. absent pulmonic component of the second heart sound.</p>
<p>Answer: C
Rationale:
Signs and symptoms of cor pulmonale/pulmonary hypertension are described. The ECG findings in answer C are seen with right ventricular and atrial hypertrophy that results. Pulmonary arterial pressure would be elevated in this scenario. LVH may be seen as late sequelae, but not typically. The pulmonic component of the second heart sound is accentuated rather than absent.
Reference:
Stoelting, Dierdorf, Anesthesia and Co-Existing Disease, 4th edition, p. 128, 2002.
Andreoli, et al, Cecil Essentials of Medicine, 5th edition, p.155-156, 2001.</p>
<p>Which of the following has a progressive PR interval increase? A. First degree heart block B. Mobitz I second degree heart block C. Mobitz II second degree heart block D. Third degree heart block</p>
<p>Answer: B
Rationale:
Mobitz type I second degree AV block is also associated with less than compensatory pause, and a normal QRS duration. It may be seen with drug toxicity such as digitalis and beta blockers.
First-degree heart block, or first-degree atrioventricular (AV) block, is defined as prolongation of the PR interval on the ECG to more than 200 msec.
With first-degree AV block, every atrial impulse is transmitted to the ventricles, resulting in a regular ventricular rate. This type of AV block can arise from delays in the conduction system in the AV node itself, the His-Purkinje system, or a combination of both
Second-degree heart block, or second-degree atrioventricular (AV) block, refers to a disorder of the cardiac conduction system in which some atrial impulses are not conducted to the ventricles. Electrocardiographically, some P waves are not followed by a QRS complex. Second-degree AV block is composed of 2 types: Mobitz I or Wenckebach block, and Mobitz II.
The Mobitz I second-degree AV block is characterized by a progressive prolongation of the PR interval, which results in a progressive shortening of the R-R interval. Ultimately, the atrial impulse fails to conduct, a QRS complex is not generated, and there is no ventricular contraction. The PR interval is the shortest in the first beat in the cycle, while the R-R interval is the longest in the first beat in the cycle.
The Mobitz II second-degree AV block is characterized by an unexpected nonconducted atrial impulse. Thus, the PR and R-R intervals between conducted beats are constant Complete heart block, also referred to as third-degree heart block, or third-degree atrioventricular (AV) block, is a disorder of the cardiac conduction system, where there is no conduction through the AV node. Therefore, complete disassociation of the atrial and ventricular activity exists. The ventricular escape mechanism can occur anywhere from the AV node to the bundle-branch Purkinje system.</p>
<p>A 64 year-old female is now two days postoperative from a iliac crest graft harvest for a mandibular defect reconstruction. She continues to have dyspnea at rest since emergence from anesthesia. Her B-type natriuretic peptide (BNP) assay is elevated. This may indicate that the patient is suffering from:
A. pulmonary embolism.
B. chronic obstructive pulmonary disease.
C. metabolic acidosis.
D. congestive heart failure.</p>
<p>Answer: D
Rationale:
BNP is a neurohormone that is released by the ventricular myocardium in response to ventricular volume and pressure overload. In patients who present with dyspnea of unknown etiology, a plasma BNP > 100 picograms/milliliter (pg/mL) can be used as evidence of heart failure as a cause of the dyspnea (diagnostic accuracy = 84%). This is useful in differentiating dyspnea due to heart failure from noncardiac causes.
Reference:
Marino, L., The ICU Book, Lippincott Williams & Wilkins Philadelphia, 2006, p. 262
Angeja, B.G., Grossman, W., Evaluation and Management of Diastolic Heart Failure, Circulation 2003; 107; 659-663 http://circ.ahajournals.org/cgi/content/full/107/5/659
ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the AdultóSummary Article: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, Journal of the American College of Cardiology, Volume 46, Issue 6, 20 September 2005, Pages 1122- 1123</p>
<p>A 70 year-old male is undergoing multiple tooth extractions. Shortly after administering local anesthesia with epinephrine he complains of crushing substernal chest pain that radiates to his left arm. What is the most appropriate initial therapeutic intervention? A. Sublingual nitroglycerin B. Supplemental oxygen C. Crushed aspirin 325 mg PO D. Intramuscular morphine sulfate</p>
<p>Answer: B
Rationale:
The patient being treated is likely suffering from an ischemic myocardial injury as described with the symptom of substernal chest pain. Despite the common acronym MONA, the initial treatment of ischemic heart disease is oxygen, nitroglycerin, aspirin, and morphine, in that order. Oxygen administration may limit ischemic myocardial injury, although its effects on morbidity and mortality of acute infarction are unknown. A short period of initial routine oxygen supplementation is reasonable during initial stabilization of the patient, given its safety and the potential for underrecognition of hypoxemia. Farther down the chain of early treatment of chest pain, a 12 lead ECG would be obtained early in the assessment of his chest pain. Later, cardiac marker enzymes levels (Troponin T, Troponin I, CK-MB) would be used in the diagnosis of myocardial injury.
Reference:
American Heart Association: Handbook of Emergency Cardiovascular Care for Healthcare Providers, American Heart Association, Dallas Texas, 2006, pages 22 - 28
ACC/AHA 2007 Guidelines for the Management of Patients With Unstable Angina/Nonñ ST-Elevation Myocardial Infarction: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 2002 Guidelines for the Management of Patients With Unstable Angina/NonñST-Elevation Myocardial Infarction), Journal of the American College of Cardiology, Volume 50, Issue 7, 14 August 2007, page 39</p>
<p>What are the beneficial effects of using ACE inhibitors and diuretics in combination for the treatment of congestive heart failure?
A. Positive chronotropic and inotropic effects
B. Negative chronotropic and inotropic effects
C. Increase preload and afterload
D. Decrease preload and afterload
</p>
<p>Answer: D
Rationale:
ACE inhibitors and diuretics are recommended for routine use in treating CHF.
ACE inhibitors block the renin-angiotensin-aldosterone system producing vasodilation by limiting angiotensin II-induced vasoconstriction. The vasodilation is predominantly arterial which decreases afterload. This decreases myocardial work and decreases myocardial energy requirements.
Diuretics decrease extracellular fluid thereby decreasing ventricular filling pressures or preload. This treats the symptoms of CHF.
Reference:
ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the AdultóSummary Article: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines, Journal of the American College of Cardiology, Volume 46, Issue 6, 20 September 2005, Pages 1128- 1129
Cooper, D., The Washington Manual of Medical Therapeutics, 32nd Edition, Chapter 6, pages 171 and 174, 2007</p>
<p>Listen to the attached audio clip and identify the cause of the heart murmur. A. Aortic valve regurgitation B. Mitral valve regurgitation C. Tricuspid valve regurgitation D. Ventricular septal defect</p>
<p>Answer: A Rationale: Tricuspid valve regurgitation, mitral valve regurgitation, and ventricular septal defects all cause murmurs that are audible during the systolic phase of heart function. Aortic valve regurgitation occurs during the diastolic phase of heart function (represented by the longer time period between heart sounds) and most frequently occurs due to aortic root dilation or rheumatic heart disease. A portion of the LV stroke volume is expelled during systole and regurgitates in the LV during diastole leading to AR regurgitation. Aortic regurgitation occurs when the aortic valve fails to close completely and blood flows back into the left ventricle after ejection into the aorta is complete (after S2). Normally, there is a brief period of time after the aortic valve closes when the ventricle relaxes isovolumetrically (the mitral valve is also closed during this phase). But when the aortic valve is leaky, the ventricle begins to fill from the aorta after the incomplete closure of the aortic valve. This leads to an increase in ventricular volume prior to the opening of the mitral valve and normal ventricular filling. Because blood is leaving the aorta in two directions (back into the heart as well as down the arterial network), the aortic diastolic pressure falls more rapidly thereby leading to a decrease in arterial diastolic pressure. Because the ventricle fills from both the aorta and the left atrium, there is a large increase in left ventricular volume and pressure (increased preload), which is best depicted by pressure-volume loops for this condition. The increased preload causes the left ventricle to contract more forcefully (Frank-Starling mechanism), thereby increasing ventricular (and aortic) systolic pressure and increasing stroke volume to help compensate for the regurgitation. The increase in ventricular end-diastolic pressure, however, also leads to an increase in left atrial pressure, which can result in pulmonary congestion and edema. Regurgitation, coupled with enhanced left ventricular stroke volume, results in a characteristic widening of the aortic pulse pressure. The backward flow of blood into the ventricular chamber during diastole results in a diastolic murmur between S2 and S1.</p>
<p>Which of the following is the risk factor for sudden cardiac death in a patient with aortic stenosis? A 1% B. 5% C. 10% D. 15%</p>
<p>Answer: B
Rationale:
Aortic stenosis (AS) is the obstruction of blood flow across the aortic valve. AS has several etiologies: congenital unicuspid or bicuspid valve, rheumatic fever, and degenerative calcific changes of the valve.
Pathophysiology: When the aortic valve becomes stenotic, resistance to systolic ejection occurs and a systolic pressure gradient develops between the left ventricle and the aorta. Stenotic aortic valves have a decreased aperture that leads to a progressive increase in left ventricular systolic pressure. This leads to pressure overload in the left ventricle, which, over time, causes an increase in ventricular wall thickness (ie, concentric hypertrophy). At this stage, the chamber is not dilated and ventricular function is preserved, although diastolic compliance may be affected.
Eventually, however, the left ventricle dilates. This, coupled with a decrease in compliance, is associated with an increase in left ventricular end-diastolic pressure, which is increased further by a rise in atrial systolic pressure. A sustained pressure overload eventually leads to myocardial decompensation. The contractility of the myocardium diminishes, which leads to a decrease in cardiac output. The elevated left ventricular end-diastolic pressure causes a corresponding increase in pulmonary capillary arterial pressures and a decrease in ejection fraction and cardiac output. Ultimately, congestive heart failure (CHF) develops.
In the US: This is a relatively common congenital cardiac defect. Incidence is 4 in 1000 live births.
Mortality/Morbidity: Sudden cardiac death occurs in 3-5% of patients with AS. Adults with AS have a 9% mortality rate per year. Once symptoms develop the incidence of sudden death increases to 15-20%, with average survival duration of less than 5 years. Patients with exertional angina or syncope survive an average of 3 years. After the development of left ventricular failure, life expectancy is slightly greater than 1 year.
</p>
<p>The above EKG shows which of the following rhythms?</p>
<p>A. Ventricular escape rhythm B. First degree heart block C. Second degree heart block D. Third degree heart block</p>
<p>Answer: D Rationale: The ECG with third degree heart block has the following three characteristics: P waves are present with a regular atrial rate faster than the ventricular rate, QRS complexes are present with a slow ventricular rate, and the P waves bear no relation to the QRS complexes, and the PR intervals are completely variable because the atria and ventricles are electrically disconnected. First-degree AV block, defined as a PR interval exceeding 200 milliseconds in an adult (180 milliseconds in adolescents), is more accurately described as first-degree AV conduction delay. Second degree heart block is divided into Mobitz I and Mobitz II. Mobitz type I, also called Wenckebach, results in progressive lengthening of the P-R interval with eventual drop of a QRS complex. Mobitz II is characterized by the sudden loss of a QRS complex without P-R elongation. Reference: Goldberger: Clinical Electrocardiography: A Simplified Approach, 7th ed., Copyright © 2006 Mosby, An Imprint of Elsevier Rakel: Conn's Current Therapy 2006, 58th ed., Copyright © 2006 Saunders, An Imprint of Elsevier</p>
<p>Below is a gram stain of drainage from a neck wound. Which of the following is the most appropriate initial oral antibiotic therapy?</p>
<p>(Picture-Gram positive cocci)</p>
<p>Metronidazole</p>
<p>Trimethoprim-sulfamethoxazole</p>
<p>Penicillin</p>
<p>Vancomycin</p>
<p>Answer: B</p>
<p>Rationale:<br></br>
The gram stain of gram-positive cocci in clusters is consistent with staphylococcus, which is aerobic. Metronidazole has antimicrobial activity against anaerobic bacteria. Penicillin has some antimicrobial against staphylococcus that does not produce penicillinase. The gram stain does not provide any insight as to whether the bacteria produce penicillinase, so this would be a poor choice. Vancomycin does have excellent antibacterial properties against staphylococcus, but it is not absorbed when taken orally. Trimethoprim- sulfamethoxazole, although typically prescribed for its activity against gram negative bacteria, also has excellent antibacterial properties against staphylococcus, is well absorbed orally, and is the most appropriate initial antibiotic of those listed.</p>
<p>Reference:<br></br>
McCarter, YS In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 47-50.</p>
<p>Hupp, JR In Topazian, RG, Goldberg, MH, Hupp, JR, editors: Oral and Maxillofacial Infections, ed 4, Philadelphia, 2002, W B Saunders Co., pp 112-125.</p>
<p>A patient with a severe cervicofacial infection is noted to have tea-colored urine. The presence of which of the following on urinalysis would suggest necrotizing fasciitis?</p>
<p>Bilirubin</p>
<p>Hemoglobin</p>
<p>Myoglobin</p>
<p>Haptoglobin</p>
<p>Answer: C</p>
<p>Rationale:<br></br>
Necrotizing fasciitis can be associated with rhabdomyolysis and secretion of myoglobin in the urine. Although severe infections can be associated with hemolysis and subsequent hemoglobinuria, and increased urine bilirubin, these parameters are not suggestive of underlying muscle inflammation and necrosis. Haptoglobin binds hemoglobin and is too large a molecule to be filtered n the urine.</p>
<p>Reference:<br></br>
Marx: Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed., Copyright © 2002 Mosby, Inc. pp.1763-1766</p>
<p>Hoffman: Hematology: Basic Principles and Practice, 3rd ed., Copyright © 2000 Churchill Livingstone, Inc., p. 408.</p>
<p>Antibiotic prophylaxis prior to dentoalveolar surgery is recommended for which disorder?</p>
<p>A. Mitral valve prolapse</p>
<p>B. Mitral valve prolapse with regurgitation</p>
<p>C. Artificial heart valves</p>
<p>D. Calcified aortic stenosis</p>
<p>Answer: C</p>
<p>Rationale:<br></br>
According to the newest AHA guidelines (11) from (4-19-2007):<br></br>
Antiobiotic prophylaxis is required prior to dental surgery only for the following conditions:</p>
<p>1. 2. 3.</p>
<p>Artificial heart valves<br></br>
A history of having had bacterial endocarditis<br></br>
Certain specific, serious congenital (present from birth) heart conditions, including:</p>
<p>a) Unrepaired or incompletely repaired cyanotic congenital heart disease, including those with palliative shunts and conduits</p>
<p>b) A completely repaired congenital heart defect with prosthetic<br></br>
Material or device, whether placed by surgery or by catheter intervention, during the first six months after the procedure</p>
<p>c) Any repaired congenital heart defect with residual defect at the site or adjacent to the site of a prosthetic patch or a prosthetic device</p>
<p>d) A cardiac transplant which develops a problem in a heart valve.</p>
<p></p>
<p>Reference:<br></br>
Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL,<br></br>
Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns<br></br>
JC, Ferrieri P, Gardner T, Goff D, and Durack DT. Prevention of Infective Endocarditis. Guidelines from the American Heart Association.<br></br>
A Guideline from the American Heart Association Rheumatic Fever,<br></br>
Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular<br></br>
Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation 2007</p>
<p>Which factor decreases a patientís risk for post-operative mandibular fracture after third molar removal?</p>
<p>A. Female gender</p>
<p>B. Age greater than 25 years-old</p>
<p>C. Full dentition</p>
<p>D. Distoangular position of the third molar</p>
<p>Answer: A</p>
<p>Rationale:<br></br>
The main factors that increase the risk for post-operative mandible fracture after third molar removal are: 1) age greater than 25 years-old</p>
<p>2) male gender 3) full dentition</p>
<p>Reference:<br></br>
Libersa P, Roze D, Cachart T, Libersa JC. Immediate and late mandibular fractures after third molar removal. J Oral Maxillofac Surg. 2002; 60:163-165; discussion 165-166.</p>
<p>Krimmel M, Reinert S. Mandibular fracture after third molar removal. J Oral Maxillofac Surg. 2000; 58:1110-1112.</p>
<p>Which of the following best characterizes the basement membrane surface of Alloderm (acellular dermal matrix), when used as an interpositional graft for root coverage?</p>
<p>A. Retains reddish coloration after contact with the patientís blood</p>
<p>B. Facilitates epithelial cell migration</p>
<p>C. Should be placed away from the exposed surface intended for coverage</p>
<p>D. Promotes revascularization</p>
<p>Answer: B</p>
<p>Rationale:<br></br>
The basement membrane surface of the Alloderm graft facilitates epithelial cell migration and attachment. The connective tissue side contains vascular channels that allow for cellular infiltration and revascularization. The basement membrane surface should be placed in contact with the exposed root surface when attempting to achieve root coverage, as this is an epithelial surface. The connective tissue surface retains a reddish coloration after contact with the patient's blood; the basement membrane side remains white.</p>
<p>Reference:<br></br>
Miloro M et al, Peterson's Principles of Oral and Maxillofacial Surgery. Pages 220-221, Second Edition, BC Decker, 2004.</p>
<p>Babbush CA et al, Dental Implants. The Art and Science. Implant Periabutment Tissue. Pages 127-129, WB Saunders, 2001.</p>
<p>A semilunar flap technique for coverage of a root with marginal tissue recession is indicated in which of the following situations?</p>
<p>A. Absence of interdental papilla</p>
<p>B. Thin scalloped periodontium</p>
<p>C. Lack of severe facial ridge curvature</p>
<p>D. Inadequate zone of keratinized tissue</p>
<p>Answer: C</p>
<p>Rationale:<br></br>
A semilunar flap technique will not recreate the dental papilla and it exhibits poor success in patients with thin scalloped periodontium. If there is not an adequate zone of keratinized tissue to start, the procedure cannot be accomplished. A severe facial curvature of the bone will also prevent success of the technique.</p>
<p>Reference:<br></br>
Nasr H, Atlas of the Oral and Maxillofacial Surgery Clinics of North America, Vol 7 Number 2, Sept 1999, pg 29-37</p>
<p>Tarnow, D, Solving Restorative Esthetic Dilemmas with the Semilunar Coronally Positioned Flap Journal of Esthetic and Restorative Dentistry 6 (2) 1994, 61ñ64.</p>
<p>Which of the following is a limitation of the palatal connective tissue graft technique?</p>
<p>A. High incidence of poor healing</p>
<p>B. Dependence on smooth palate donor site</p>
<p>C. Graft availability is dependent on donor site thickness</p>
<p>D. High incidence of neurovascular injury</p>
<p>Answer: C</p>
<p>Rationale:<br></br>
Connective tissue grafting extremely useful in that is does not depend upon a smooth palate and heals very well. The incidence of neurovascular injury is also very low if harvested in the classic manner (anterior to the maxillary first molar.) Depending upon the thickness of a particular patient's tissue, the amount of graft available may be minimal and therefore some patients may require secondary grafting several months later.</p>
<p>Reference:<br></br>
Sclar A, Alpha Omegan, Volume 93, number3, Aug/Sept 2000, pg 38-46.</p>
<p>Fonseca, et al. Oral and Maxillofacial Surgery: Reconstruction and Implant Surgery. (Vol 7). WB Saunders Company. Philadelphia. 2000, pp 335-8.</p>
A trauma patient in the surgical intensive care unit has the following blood gas result.
pH 7.32 (normal range 7.36 ñ 7.44)
PaCO2 46 mm Hg (normal range 36-44 mm Hg) HCO3 23 mEq/L (normal range 22-26 mEq/L)
This finding is indicative of which condition?
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis
Answer: A
Rationale:
Respiratory acidosis occurs when the pH is below 7.36 and PaCO2 is above 44 mm/Hg. Respiratory alkalosis occurs when the pH is above 7.44 and PaCO2 is below 36 mm/Hg. Metabolic acidosis has a pH below 7.36 and HCO3 is below 22 mm/Hg. Metabolic alkalosis has a pH above 7.44 and HCO3 is higher than 26 mm/Hg.
Respiratory acidosis occurs with impairment in the rate of alveolar ventilation. Acute respiratory acidosis occurs with a sudden depression of the medullary respiratory center, paralysis of the respiratory muscles, and with airway obstruction. Therapy is aimed at treatment of the underlying disorder and ventilatory support. The question above refers to uncompensated respiratory acidosis. The body does use metabolic and respiratory compensatory mechanisms to maintain a constant PaCO2/ HCO3 ratio. For example in a primary respiratory acidosis or alkalosis, the kidneys provide the compensation by adjusting the HCO3 reabsorption. In a primary metabolic disorder, the ventilatory system is mediated by H+ sensitive chemoreceptors in the carotid body which signal an increase or decrease in ventilation to alter arterial PaCO2 levels. The amount of compensation can be calculated using the pH, PaCO2, and bicarbonate level.
Respiratory alkalosis occurs with hyperventilation. It can occur in pregnancy, fever and septic states, with pneumonia, pulmonary embolism, and congestive heart failure. Acute hyperventilation is characterized by light-headedness, paresthesia, circumoral numbness, and tingling of the extremities. Tetany occurs in severe cases.
Metabolic acidosis can be due to extrarenal loss of bicarbonate, as in diarrheal diseases, but can also be caused by high renal excretion of bicarbonate.
Metabolic alkalosis is caused by things such as excessive vomiting and diuretic use leading to volume depletion. It occurs due to a failure to the kidney to excrete excess bicarbonate. Treatment is directed at correction of the metabolic disorder.
American Board of Oral and Maxillofacial Surgery
18
2008 Oral and Maxillofacial Surgery Self Assessment Tool (OMSSAT)
Reference:
The ICU Book, 2nd ed., Marino, Williams and Wilkins, 1997 p. 584-586
Cecil Essentials of Medicine, 7th ed. Andreoli and Carpenter, Saunders, 2007, 298-303.
Which of the following is the most important risk factor for developing nosocomial pneumonia? A. Malnutrition B. Mechanical ventilation C. Nursing home residence D. Tobacco abuse
Answer: B
Rationale:
While malnutrition, tobacco use, and residency in a nursing home facility are risk factors, endotracheal intubation and mechanical ventilation is by far the most important contributor leading to nosocomial pneumonia. Endotracheal intubation provides a pathway for bacterial contamination in the lungs.
This is increased in the patient with chest trauma or lung injury. The aspiration of oral secretions into the upper airways is the inciting event in most cases of pneumonia. Averages of 1 billion bacteria are found in each milliliter of saliva.
Reference:
Kokko, J., Stein, S., The Emory University Comprehensive Board Review in Internal Medicine. McGraw-Hill. New York, 2000, p. 286.
Mandell, Bennett, & Dolin: Principles and Practice of Infectious Diseases, 6th ed., Chapter 314 ñ Infections in the Elderly, Pneumonia, Copyright © 2005 Churchill Livingstone, An Imprint of Elsevier
Marino, P., The ICU Book. Lippincott Williams Wilkins. Baltimore, 2004, p. 516-517.
Chronic complications of which disease process includes cirrhosis of the liver, pancreatic dysfunction, sinusitis, and bronchial hyperreactivity? A. Chronic bronchitis B. Cystic fibrosis C. Sarcoidosis D. Tuberculosis
Answer: B
Rationale:
Cystic fibrosis is an autosomal recessive disorder. In the Untied States, it affects 1 in 2500 Caucasians, 1 in 17000 African Americans, and 1 in 90000 Asians. Over 230 mutations have been identified with various degrees of disease severity, with the most common defect on the long arm of chromosome 7. The genetic defect causes defective chloride transport and increased sodium reabsorption in airway and ductal epithelia, creating abnormally thick and viscous secretions in the respiratory, hepatobiliary, gastrointestinal, and reproductive tracks. The thick secretions cause luminal obstruction and destruction of exocrine ducts. The median survival age is 40 years.
The disease often manifests in childhood. Respiratory complications in addition to chronic sinusitis and bronchial hyperreactivity include mucous plugging within the lungs. Mucous plugs can also occur in the salivary glands, although not common.
A diagnostic criterion is a sweat chloride concentration > 60 mEq/L. Genetic testing can also be completed to confirm the diagnosis. Clinical findings are also important in diagnosis. Presence of mucoid Pseudomonas aeruginosa in sputum is characteristic of CF. Chest radiograph abnormalities include bronchiectasis with upper lobe and right-sided predominance. Digital clubbing and hypertrophic osteoarthropathy are present. Spontaneous pneumothorax and pulmonary hypertension are negative prognostic findings.
Standard therapy for CF includes chest physical therapy, antibiotics as needed, adequate nutrition, and exercise. Bronchodilators may be used for patients with bronchospasm or airflow limitation. Lung transplants for patients with advanced CF are being performed.
Reference:
Kokko, J., Stein, S., The Emory University Comprehensive Board Review in Internal Medicine. McGraw-Hill. New York, 2000, p. 305-306.
Andreoli T: Cecil Essentials of Medicine, W. B. Saunders Company, Philadelphia, 2001, p. 220-221.
Which of the following is commonly associated with asthma? A. Decreased lung compliance B. Obtunded cholinergic sensitivity C. Gastroesophageal reflux disease D. Hypocarbia
Answer: C
Rationale:
Upwards of 80% of asthmatics exhibit gastroesophageal reflux disease (GERD). Although respiratory disease can induce GER by increasing abdominothoracic pressure gradients, there is substantial evidence suggesting that the more common pathway is that for GER to trigger respiratory symptoms, particularly of asthma. This may occur from microaspiration with resultant direct inflammation and bronchoconstriction, from vagally mediated effects from stimulation of upper airway receptors, or from esophageal afferent irritation causing a neurogenic reflex.
Decreased lung compliance is associated with restrictive lung disease not obstructive, and asthma is an obstructive pulmonary disease.
Asthmatics commonly have increased cholinergic sensitivity.
Hypercarbia is sequelae of an asthmatic attack.
Reference:
Behrman: Nelson Textbook of Pediatrics, 17th ed., Copyright © 2004 Saunders, An Imprint of Elsevier, Chapter 387, Gastroesophageal reflux and respiratory disorders.
Mason: Murray and Nadel’s Textbook of Respiratory Medicine, 4th ed. Chapter 78 ñ Pulmonary Complications of Abdominal Disease.
Which of the following best characterize restrictive lung disease? A. Decrease in total lung capacity B. Decrease in FEV1/FVC ratio C. Increase in vital capacity D. Increase in airway resistance
Answer: A
Rationale:
Restrictive disorders are best evaluated by measuring lung volumes. The severity of the restrictive defect is based on the TLC (total lung capacity). In restrictive lung disorders, the FEV1 may be decreased, but the FEV1/FVC ratio will be preserved. The TLC, FRC (functional residual capacity) and RV (residual volume) will all be decreased. Airway resistance is not affected in a restrictive lung disease.
Restrictive disorders can occur in three circumstances: lung disorders, disorders of the chest wall, and neuromuscular disease. Lung disorders with interstitial infiltration typically show restriction caused by increased elastic recoil such as observed in idiopathic pulmonary fibrosis and sarcoidosis. Lung edema as a result of congestive heart failure can also cause a restrictive pattern. Chest wall abnormalities may exhibit themselves with a restrictive pattern by restricting lung expansion as observed in kyphoscoliosis, obesity , and ankylosing spondylitis, Included in the chest wall abnormalities are the pleural diseases (pleural effusion, pneumothorax,), space occupying lesions (tumors), and conditions causing increased abdominal girth such as pregnancy, ascites, and large intra-abdominal tumors. Some neuromuscular disorders cause restriction by preventing normal excursion of the lung during breathing as observed in patients with myasthenia gravis, amyotrophic lateral sclerosis, diaphragmatic paralysis, and the Guillain-Barre syndrome. Patients may also restrict lung excursion during inspiration as a result of pain or somnolence (drug overdose). Lung resection during lobectomy will also cause a restrictive defect.
Decrease in the FEV1/FVC ratio is the hallmark of obstructive lung disease. Airway resistance is increased in obstructive lung disease (asthma).
Reference:
Andreoli T: Cecil Essentials of Medicine, W. B. Saunders Company, Philadelphia, 2001, p. 208-210.
Clinical Anesthesiology 4th ed., Lange Medical Books/McGraw Hill, New York, 2006 pp572-580
What is the most likely diagnosis for a patient with the following findings after pulmonary function testing? FVC - normal FEV1 - decreased FEV1/FVC - decreased A. Respiratory muscle weakness B. Obstructive lung disease C. Restrictive lung disease D. Spontaneous pneumothorax
Answer: B
Rationale:
Obstructive lung disease includes asthma, chronic bronchitis, emphysema, bronchiectasis, cystic fibrosis, and upper airway obstruction.
Diseases such as asthma and bronchitis, which obstruct the airway, reduce expiratory flow rates and therefore reduce FEV1 and FEV1/FVC. An obstructive defect is essentially characterized by a disproportionate decrease in the airflow rate relative to the actual volume exhaled (i.e., FVC) and indicates airway narrowing and flow limitation during expiration. Values for FEV1/FVC that are lower than 70% reflect mild obstruction, those lower than 60% suggest moderate obstruction, and those lower than 50% indicate severe obstruction.
In restrictive lung disease and respiratory muscle weakness, the forced vital capacity and FEV1 are decreased, while the FEV1/FVC ratio is normal. Pneumothorax can be considered a restrictive lung disease.
Reference:
Andreoli T: Cecil Essentials of Medicine, W. B. Saunders Company, Philadelphia, 2001, p. 208-210.
Kokko, Jl, Stein,S., The Emory University Comprehensive Board Review in Internal Medicine. Pg 271-283, 301-311 McGraw-Hill. New York, 2000.
Which is considered the most definitive in the diagnosis of pulmonary embolism?
A. Ultrasound of femoral-popliteal system
B. Nuclear ventilation-perfusion scan
C. Chest radiograph
D. Contrast-enhanced CT scan
Answer: D
Rationale:
Pulmonary embolism (PE) is usually a complication of venous thrombosis in the deep veins of the lower extremities that originate in the femoral-iliac-pelvic veins. Causes of thrombosis include: vessel injury, hypercoagulability, and stasis. The best treatment of PE is prevention, especially in high risk patients (malignancy, obesity, age greater than 40, PE history, extensive surgery, and immobilization). In hemodynamically unstable patients it is important to definitively diagnose and treat. The test that was considered the ìgold standardî for many years was pulmonary angiogram. Helical or multi-detector CT scans are now becoming the preferred test for definitive diagnosis.
In hemodynamically stable patients the following is a suggested treatment protocol.
1) Maintain high index of suspension
2) Signs and symptoms: - dyspnea, tachypnea, tachycardia, chest pain, PO2 less than 80 (none is completely diagnostic)
3) Chest XR: may show localized volume loss, atelectasis, peripheral infiltrates, and/or pleural effusions
4) Ventilation-perfusion scan (V/Q): This scan uses lung ventilation with radiolabeled tracer gas with lung perfusion by radiolabeled microocclusive particles. A normal scan will rule out PE. Results of a low or intermediate scan gives likelihood between 15-55% and usually indicates pulmonary angiogram for conformation. The results of V/Q are dependent on quality of the scan, interpretation of the scan, and clinical probability of PE. 5) Impedance plethysmography and Doppler ultrasonograph are noninvasive techniques for diagnosis of deep vein thrombosis in the lower extremity that may support diagnosis of PE. These tests have a low sensitivity. Venous duplex scanning (ultrasonic venous imaging with Doppler blood-flow imaging) has greater accuracy than the above procedures.
6) Contrast-enhanced CT is increasingly used as the initial radiologic study in the diagnosis of PE, especially in patients with abnormal chest radiographs in whom scintigraphic results are more likely to be nondiagnostic.
CT show emboli directly, as does pulmonary angiography, and it is also noninvasive, cheaper, and widely available. CT is the only test that can provide significant additional
information related to alternate diagnoses; this is a clear advantage of CT compared with either pulmonary angiography or scintigraphy.
Because DVT and PE are part of the same disease process, CT venography can easily be performed after CT pulmonary angiography.
When PE is identified, it is characterized as acute or chronic. An embolus is acute if it is situated centrally within the vascular lumen or if it occludes a vessel (vessel cutoff sign). Acute PE commonly causes distention of the involved vessel. An embolus is chronic if (1) it is eccentric and contiguous with the vessel wall, (2) it reduces the arterial diameter by more than 50%, (3) evidence of recanalization within the thrombus is present, and (4) an arterial web is present.
PE is further characterized as central or peripheral, depending on the location or the arterial branch involved. Central vascular zones include the main pulmonary artery, the left and right main pulmonary arteries, the anterior trunk, the right and left interlobar arteries, the left upper lobe trunk, the right middle lobe artery, and the right and left lower lobe arteries. Peripheral vascular zones include the segmental and subsegmental arteries of the right upper lobe, the right middle lobe, the right lower lobe, the left upper lobe, the lingula, and the left lower lobe.
7) Pulmonary angiogram: The last test in this protocol because of its invasive nature and inherent risk. The role of conventional angiograghy is limited to patients in which other results are non-diagnostic and/or clinical suspicions are high.
D-dimer: Blood test that is used as an aid to diagnose thrombosis. It is best used to rule out thromboembolic disease when probability is low. A negative result practically rules out thrombosis and a positive test may indicate thrombosis but does not rule out other etiologies (DIC) and requires further testing for DVT/PE.
D-dimer is unique in that they are breakdown products of fibrin mesh after being stabilized/cross-linked by Factor XIII. This is the final step in the generation of a thrombosis and indicate a thrombosis is present.
Reference:
Kokko, J. Stein, S., The Emory University Comprehensive Board Review in Internal Medicine. Pg 327-331 McGraw-Hill New York, 2000.
Marino, P The ICU Book. Pg 106-115, 376-379 Lippincott Williams Wilkins. Baltimore, 2006.
Eng, j. Krishman, JA. Segal, J. Bolger, D. Tamariz, L. Accuracy of CT in the Diagnosis of Pulmonary Embolism. Journal of Roentololgy. 2004; 183:1819-1827.
Which of the following pharmacologic groups is a risk factor for venous thromboembolism? A. Hypercholesterolemics B. Estrogen replacement therapy C. Non steroidal anti-inflammatories D. ACE inhibitors
Answer: B
Rationale:
Estrogens and birth control pills are can result in hypercoagulability and are a risk factor for venous thromboembolism Pulmonary embolism is usually a complication of venous thrombosis of the femoral-iliac-pelvic-popliteal system of the lower extremity. Factors that may contribute to thrombosis include: venous stasis, hypercoagulability, endothelial injury. Patient risk factors include: heart failure, malignancy, immobilization, trauma, obesity, advanced age, pregnancy, extensive surgery, and oral contraceptives.
There is no data to support hypercholerterolemics, NSAID’s or ACE inhibitors as risk factors for venous thromboembolism.
Prevention is the best treatment which includes: intermittent compression device, anti- embolism stocking, selective heparin use, and early post-operative ambulation.
Reference:
Kokko, J., Stein, S., The Emory University Comprehensive Board Review in Internal Medicine. McGraw-Hill. New York, 2000, p.329-331.
Marino, P. The ICU Book. Lippincott Williams Wilkins. Baltimore, 2006, p. 106-108.
What is the first course of action for patients strongly suspected or documented to have a deep vein thrombosis (DVT)? A. Warfarin B. Thrombectomy C. Heparin D. Streptokinase
Answer: C
Rationale:
Treatment should include supportive care for hypoxemia and hypotension. Anticoagulation with IV heparin should be started as soon clinical suspicion of PE without waiting for diagnostic studies. The goal is for 1.5-2.5 times the control value of PTT for 5-10 days. Any delay in reaching therapeutic PTT range has been shown to increase the risk of progressive thrombosis and recurrent pulmonary embolism. Then, warfarin therapy is initiated with an INR goal of 2-3 for 3-6 months or indefinitely if patient is at high risk. If contraindications exist for anticoagulation or if patient has reoccurrence of PE in spite of anticoagulation the treatment of choice is vena caval interruption. (Greenfield filter). Systemic thrombolytic therapy and embolectomy may be indicated in very rare cases.
Heparin (unfractionated) is a glycosaminoglycan with varying molecular size. It potentiates the action of antithrombin III thereby inactivating thrombin and prevents the conversion of fibrinogen to fibrin.
Low molecular weight heparin (LMWH) has been used in place of the unfractionated heparin with comparable results for treatment of DVT’s and non-massive PE. LMWH is enzymatically broken down into smaller more uniform molecules with less variation in anti-coagulation response. Because of the predictability of the response and route of administration these patients are, in some cases, treated as outpatients, dramatically reducing cost but not changing clinical outcomes. LMWH is given subcutaneously with a slower onset then IV heparin but dosing is less frequent, there is less heparin-induced thrombocytopenia, less heparin-induced osteoporosis, and slightly less risk of bleeding.
Reference:
Green, GB, Harris, IS., Lin, GA., Moylan, KC., The Washington Manual of Medical Therapeutics, 31st Edition. Lippincott Williams Wilkins. Baltimore, 2004.
Marino, P., The ICU Book. Pg 112-115, 376-379 Lippincott Williams Wilkins. Baltimore, 2004.
A 60 year-old patient reports a history of smoking and frequent productive cough present for at least three months in each of the last two years. What is the most likely diagnosis? A. Emphysema B. Cystic fibrosis C. Asthma D. Chronic bronchitis
Answer: D
Rationale:
Chronic bronchitis is defined as the presence of a productive cough for at least 3 months in each of the past 2 years in a person with excessive mucous secretion not due to other disease. The most common cause is cigarette smoking. Chronic bronchitis may result in carbon dioxide retention, chronic hypoxemia, erythrocytosis, pulmonary hypertension and right heart failure. The respiratory drive becomes less sensitive to carbon dioxide retention and may potentially be depressed by oxygen administration. (Blue Bloater Syndrome)
Emphysema is characterized by irreversible enlargement of the airways distal to the terminal bronchioles and destruction of the alveolar septa. Emphysema will usually have little sputum production and a cough with exertion.
Asthma is characterized by airway inflammation and hyper-reactivity in response to various stimuli. Asthma produces episodic attacks of dyspnea, cough, and wheezing. Cystic fibrosis is characterized by secretion of highly viscous mucous with fibrosis and chronic lung infections.
Reference:
Clinical Anesthesiology 4th ed., Lange Medical Books/McGraw Hill, New York, 2006 pp572-580
Rita K Cydulka: Emergency Medicine 6th ed., McGraw Hill, New York, 2004 pp 475-480
Which of the following pulmonary function tests is most useful in evaluating the asthmatic patient?
A. TLC (Total lung capacity)
B. FEV1 (Forced expiratory volume in 1 second)
C. FRC (Functional residual capacity)
D. VC (Vital capacity)
Answer: B
Rationale:
The FEV1 measures the amount of air which can be forcibly expelled in 1 second and reflects the degree of large airway obstruction. FEV1 values are normally around 3L for men and 2L for women, but vary with each individual. FEV1/FVC should normally be >70% and an FEV1 or FEV1/FRC ratio less than 50% indicates moderate to severe asthma. TLC and FRC may be elevated in obstructive disease. Obstructive disease (such as asthma) is characterized by difficult expiration. Either more force is required to expire a given volume of air, or emptying of the lungs is slowed, or both. Spirometry (Pulmonary function tests) measures both lung volume and gas flow. Pulmonary function tests will often demonstrate partial reversibility (improvement in the FEV1 of at least 15%) after the administration of bronchodilators. The absence of improvement in pulmonary function tests after the administration of a bronchodilator does not constitute proof of irreversible airway obstruction.
Reference:
Clinical Anesthesiology 4th ed., Lange Medical Books/McGraw Hill, New York, 2006 pp574
Rita K Cydulka: Emergency Medicine 6th ed., McGraw Hill, New York, 2004 pp 468
Current Medical Diagnosis and Treatment 36th ed., Appleton and Lange, Stamford CT, 1997 pp242
Pathophysiology: The Biologic Basis for Disease in Adults and Children, Mosby, St. Louis, 1990 pp 1048, 1049
Which of the following medications should be avoided in a patient with a history of nasal polyposis and moderate asthma? A. Acetaminophen (Tylenol) B. Tramadol (Ultram) C. Propoxyphene D. Diclofenac
Answer: D
Rationale:
Aspirin induced asthma (AIA) is characterized by severe and sometimes life-threatening episodes of asthma following the use of NSAIDS (nonsteroidal anti-inflammatory drugs). Individuals with AIA suffer from chronic asthma that is often steroid dependent and associated with a significant number of individuals with chronic rhinosinusitis and nasal polyps (Sampter’s Triad). AIA usually appears in the 3rd to 4th decade of life.
Patients with AIA react to NSAIDS that inhibit cyclooxygenase enzyme 1 (COX-1). COX-1 catalyzes the formation of prostaglandins and thromboxanes from cell membrane arachidonic acid. If the COX-1 is inhibited, it may cause a shift to an alternative pathway of arachidonic acid metabolism involving 5 lipoxygenase. The products of 5 lipoxygenase include various leukotrienes that are potent inflammatory mediators. These leukotrienes can act as bronchoconstrictors. These leukotrienes may also increase mucus secretion, induce swelling of the nasal mucosa, promote airway edema and attract eosinophils into the airways. Increased leukotriene concentrations have been detected in AIA patients compared to non AIA patients both at baseline and following ASA (Aspirin) challenge.
Reference:
Jonathan P. Arm, Lung Biology in Health and Disease Vol. 115., Fatal Asthma, Marcei Dekker, 1998 pp335-345
Rita K Cydulka: Emergency Medicine 6th ed., McGraw Hill, New York, 2004 pp 475-480
Namazy J., Simon R., Current Review of Asthma., Respiratory Reactions to Anti- inflammatory Drugs, Current Medicine Inc., 2003 pp91-98
Elliot Israel MD., Up To Date, 2007 Aspirin-Induced Asthma
An asthmatic patient begins to complain of severe dyspnea and a cough. Auscultation of the lungs reveals wheezing. Which of the following drug classes reflects the preferred initial treatment? A. Xanthines B. Adrenergics C. Anticholinergics D. Corticosteroids
Answer: B
Rationale:
Beta adrenergic agents are the preferred initial rescue medication for acute bronchospasm. The ideal beta adrenergic agent would possess pure beta 2 selective activity without cardiac side effects. Older catecholamine bronchodilators such as epinephrine and isoproterenol are not beta 2 specific and have a short duration of action. Epinephrine (1:1000 or 1mg/ml 0.3mg-0.5mg SC every 20 minutes for 3 doses) may be given to patients unable to coordinate aerosolized or MDI treatments. Newer agents such as the resorcinol bronchodilators (metaproterenol, terbutaline and fenoterol) and saligenin bronchodilators (albuterol and carbuterol) have greater beta 2 specificity and a longer duration of action. Albuterol is an inhaled short-acting beta 2 agonist that can be administered as a nebulized solution or as an MDI (metered dose inhaler). Albuterol via MDI may be given at 90ug/puff with 4-8 puffs every 20 minutes up to 4 hours for the adult patient. Xanthines include medications such as theophylline. They are not considered a first line treatment for acute asthma. Xanthines are frequently reserved for those patients whose symptoms persist despite the use of an inhaled steroid and beta 2 antgonist. Therapeutic levels are often associated with gastrointestinal, cardiac, and central nervous system side effects. There is a narrow therapeutic index, toxicity may occur and be fatal. Anticholinergics such as atropine or ipratropium bromide are bronchodilators, but their usage can produce side effects such as tachycardia. Corticosteroids such as hydrocortisone and betamethasone are highly effective in the chronic management of asthma by reduction of lumen mucosa inflammation, and they may restore some beta adrenergic responsiveness, but the onset of the effect may be delayed 4-8 hours.
Reference:
Clinical Anesthesiology 4th ed., Lange Medical Books/McGraw Hill, New York, 2006 pp572-576
Rita K Cydulka: Emergency Medicine 6th ed., McGraw Hill, New York, 2004 pp 467-473
Auscultation of the lungs reveals the finding on the attached audio clip. What is the finding that you hear?
Sound 2: Please note that sound is not available in this format but the item content is appropriate for learning purposes.
A. Normal breath sounds
B. Rales
C. Wheezing
D. Crackles
Answer: C
Rationale:
The breath sound in the clip is an expiratory wheeze. Wheezing is caused by high-velocity air flow through a narrowed or obstructed airway. The longer the wheeze and the higher the pitch, the worse the obstruction. If a wheeze is heard bilaterally, it may be caused by asthma or acute or chronic bronchitis.
Crackles are heard most often during inspiration and are characterized by discrete discontinuous sounds, each lasting a few milliseconds. Crackles may be fine and high pitched or coarse and low pitched. They are caused by the disruptive passage of air through the small airways in the respiratory tree. Rales is another term for crackles. Crackles are due to abnormalities of the lungs (pneumonia, fibrosis, early congestive heart failure), or of the airways (bronchitis, bronchiectasis).
Reference:
Mosby’s Guide to Physical Examination, 6th ed. Seidel et al, 2006, p 386-387
Audio clip used with permission from Dr. Samuel Louie, University of California-Davis. Other examples of respiratory sounds can be heard at http://medocs.ucdavis.edu/IMD/420C/sounds/lngsound.htm
A 25 year-old male is undergoing general anesthesia for treatment of a mandible fracture. The anesthesiologist notes difficulty ventilating the patient and obtains the attached radiograph. What treatment is appropriate for the patient's condition? A. Placement of a needle on the right B. An albuterol nebulizer treatment C. Antibiotics D. Placement of a chest tube on the left
Answer: A
Rationale:
A tension pneumothorax is the accumulation of air in the pleural space, creating positive pressure. Because tension pneumothorax can cause hemodynamic compromise, this medical emergency requires immediate decompression. In addition to resistance to ventilation, the blood pressure decreases and central venous pressure increases. The increased pressure should be relieved immediately with needle thoracostomy, which is performed by inserting a large-bore (16 or 18-gauge) needle through the second or third intercostal space anteriorly on the involved side. A chest tube is also appropriate treatment for a tension pneumothorax, however in this case it would be on the wrong side of the patient.
An albuterol nebulizer treatment would be used for acute asthma attack. An exacerbation of asthma under anesthesia can cause difficulty with mechanical ventilation. Antibiotics would be prescribed for pneumonia. The onset of pneumonia would not typically cause acute difficulty with ventilation.
Reference:
Marx: Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6th ed, Chapter 42
Roberts: Clinical Procedures in Emergency Medicine, 4th ed. Saunders, 2004, Chapter 10. Radiograph from Dr. Brian Mullan, MD, University of Iowa Hospitals and Clinics
A 32 year-old female presents with a chief complaint of weakness with chewing. Her symptoms are worse during evening meals. Physical examination shows diplopia and lid ptosis. If her clinical signs improved with the administration of edrophonium which of the following would you suspect?
A. Mutation in the dystrophin gene
B. Antibodies to the presynaptic voltage-gated calcium channels
C. Antibodies to sarcoglycan proteins
D. Antibodies against the postsynaptic nicotinic acetylcholine receptor
Answer: D
Rationale:
The patient is demonstrating classic findings associated with myasthenia gravis. This disease process is a result of autoantibodies to the postsynaptic nicotinic acetylcholine receptor. Its prevalence is about 1 in 7500 and although it affects all age groups, it is most common in males in their fifties and sixties, and females in their twenties and thirties. Cardinal features include weakness and fatigability of muscles which is progressive and may improve with rest. Cranial muscle weakness usually involves the eyelids and extraocular muscles early on resulting in diplopia and ptosis. Weakness with chewing may result after a prolonged effort, and nasal speech as well as difficulty swallowing may also result from palatal and pharyngeal muscle weakness. Limb weakness is proximal and may be asymmetric. Deep tendon reflexes are preserved. Occasionally, respiratory muscle weakness may develop requiring ventilatory assistance; this is known as a myasthenic crisis. Foil A is associated with Duchenne Muscular Dystrophy. Foil B represents the pathophysiology of Lambert-Eaton Myasthenic Syndrome. Foil C is the etiology of Limb- Girdle muscular dystrophy.
Reference:
Fauci et al., Harrison’s Principles of Internal Medicine 14th ed., McGraw-Hill, 1998, pp. 2469-2472.
Goetz: Textbook of Clinical Neurology, 2nd ed., Copyright © 2003 Saunders, An Imprint of Elsevier
A 67 year-old gentleman presents to your office with xerostomia and keratoconjunctivitis sicca. He has a long history of smoking and recently diagnosed lung cancer. You note intermittent eyelid ptosis, and decreased deep tendon reflexes that improve briefly with exertion, but with sustained activity worsen. Which disorder do you suspect? A. Hyperthyroidism B. Myasthenia gravis C. Oculopharyngeal dystrophy D. Lambert-Eaton myasthenic syndrome
Answer: D
Rationale:
Lambert-Eaton myasthenic syndrome is a disorder of the presynaptic neuromuscular junction. It causes symptoms that resemble closely those of myasthenia gravis. However, it is typically associated with a malignancy, most commonly small cell cancer of the lung. This is thought to be caused by autoantibodies to the calcium channels at motor nerve terminals which impairs the release of acetylcholine. Treatment of the disorder involves immunosuppression often with steroids, as well as plasmapheresis, which is often performed preoperatively, along with cessation of the anticholinesterase medications. A differential diagnosis includes: hyperthyroidism, botulism, intracranial lesions, neurasthenia, and progressive external ophthalmoplegia.
Reference:
Fauci et al., Harrison’s Principles of Internal Medicine 14th ed., McGraw-Hill, 1998, pp. 2469-2472.
Ferri: Ferri’s Clinical Advisor 2007: Instant Diagnosis and Treatment, 9th ed., Copyright © 2007 Mosby, An Imprint of Elsevier
A 5 year-old male presents to your office with his mother. In the dental chair, the boy pushes his hands against his knees to elevate his upper torso into an upright position. You also notice that his calf muscles are rather large when compared with his thighs, and that he is intellectually impaired. What is the disease process is most likely affecting this young person? A. Myasthenia gravis B. Dermatomyositis C. Polymyositis D. Duchenne muscular dystrophy
Answer: D
Rationale:
The boy performs a classic Gowers’ maneuver when elevating himself to an erect position, which is a giveaway for the diagnosis of Duchenne muscular dystrophy. This is a hereditary myopathy that is also known as pseudohypertrophic muscular dystrophy. It is an X-linked recessive disorder with an incidence of 30 per 100,000 males. While present at birth, it usually becomes apparent between the ages of 3 and 5. The boys have difficulty keeping up with physical activities with their peers, and have a progressive muscle weakness. The enlarged calves are also a classic physical finding and while inappropriately termed pseudohypertrophy, it is actually a result of fibrofatty tissue replacing the muscle in the enlarged calves. These children typically are unable to walk by age 12, and also suffer from scoliosis and contractures. They commonly suffer from intellectual impairment and have an IQ approximately one standard deviation below their peers. Cardiomyopathy is present in most of these patients, though death is usually due to pulmonary infections and an increased incidence of aspiration pneumonia.
Reference:
Fauci et al., Harrison’s Principles of Internal Medicine 14th ed., McGraw-Hill, 1998, pp. 2473-2475.
Behrman: Nelson Textbook of Pediatrics, 17th ed., Copyright © 2004 Saunders, An Imprint of Elsevier, Chapter 600.
What finding is commonly associated present with Sturge-Weber Syndrome? A. Seizures B. Lip pits C. CafÈ-au-lait spots on trunk D. Pronounced mandibular hypoplasia
Answer: A
Rationale:
The classic clinical manifestations of Sturge-Weber Syndrome are facial vascular nevi (port-wine stain), epilepsy, cognitive deficits, and hemiparesis or hemiplegia, hemianopia, glaucoma. Patients with Sturge-Weber syndrome may actually have enlargement of the associated lip, maxilla, or mandible. Cerebral angiography of these patients reveals capillary, venous and arteriovenous anomalies of the leptomeninges. The anomalous circulation is responsible for the progressive degeneration and atrophy of the cerebral hemispheres. Extensive leptomeningeal abnormalities can cause seizures, contralateral hemiplegia, and delayed motor and cognitive skills.
CafÈ-au-lait spots on a patient’s trunk are commonly associated with McCune-Albright Syndrome. Pronounced mandibular hypoplasia can be associated with such conditions as Pierre-Robin Sequence or Treacher-Collins Syndrome but is not associated with Sturge- Weber Syndrome.
Reference:
Goldman L, Ausiello D: Cecil Textbook of Medicine 22nd ed., Saunders, Philadelphia, 2003 pp 2363
Cummings: Otolaryngology: Head & Neck Surgery, 4th ed., Copyright © 2005 Mosby, Inc, Chapter 174 ñ Vascular tumors and malformations of the head and neck, capillary malformation.
A 24 year-old patient with a panfacial fracture acutely develops speech difficulties and confusion. You have been called to the surgical intensive care unit to examine him for a newly discovered maxillary fracture. While talking with the patient, he acutely develops difficulty speaking despite remaining fully conscious. His vital signs remain stable, and he recovers fully after several minutes. What is the most likely explanation for his acute speech difficulties and confusion? A. Transient ischemic attack B. Hypoglycemia C. Seizure D. Narcolepsy
Answer: C
Rationale:
Posttraumatic seizures can occur as an acute result of blunt or penetrating head trauma. Immediate posttraumatic seizures occur with 24 hours of injury, and are more common in children than in adults. Within the first year after significant head trauma, the incidence of seizures is at least 12 times that of the general population. The incidence of seizures after injury with neurologic deficit without dural violation is 7% to 39%. When the dura is disrupted, the incidence is 20 ñ 57%. Most patients with pos-traumatic epilepsy have partial seizures that can affect sensory, motor or autonomic areas of the brain. If the speech centers are involved in the ictal discharge, speech can be disturbed or arrested. These seizures are usually short lived, and the patients recover function quickly.
The other answers can be associated with speech difficulties but are not necessarily related to head trauma and have other related symptoms. A transient ischemic attack could involve speech disturbance, but the patient is in the wrong age group and did not have any other symptoms of a TIA such as decreased consciousness, nausea, vomiting, visual disturbance, or hemiplegia. Most patients who suffer TIAs do not fully recover in minutes. Hypoglycemic attacks can cause speech alteration, but they are associated with other symptoms such as confusion, loss of consciousness, nausea, and vomiting. These attacks do not usually resolve spontaneously, but rather require intervention. Narcolepsy is associated with decreased consciousness or sudden onset of a sleep state.
Reference:
Goldman L, Ausiello D: Cecil Textbook of Medicine 22nd ed., Saunders, Philadelphia, 2003 pp 2257-2269.
Marx: Rosen’s Emergency Medicine: Concepts and Clinical Practice, 6th ed, 2006; Chapter 100 ñ Seizures ñ Seizures caused by trauma.
A 25 year-old female with multiple sclerosis is undergoing surgery in the operating room under general anesthesia. Which of the following neuromuscular blocking drugs is contraindicated in this individual? A. Vecuronium B. Cisatracurium C. Rocuronium D. Succinylcholine
Answer: D
Rationale:
Neuromuscular blocking drugs should be used judiciously. Succinylcholine poses the risk of hyperkalemia due to the release of intracellular potassium. Hyperkalemia after depolarizing neuromuscular block represents a risk to all patients with muscle denervation pathology, and may lead to cardiac arrest. Patients with lesions involving motor nuclei, as evidenced by flaccidity, spasticity or hyperreflexia, are at risk for hyperkalemia. Upregulation of acetylcholine receptors even by the fourth day after the onset of symptoms leads to sensitivity to succinylcholine in multiple sclerosis patients. Patients remain at risk for hyperkalemia for months or years and succinylcholine is best avoided. The use of nondepolarizing muscle relaxants can also pose difficulties. In addition to their multiple interactions with medications taken by multiple sclerosis patients, they have a variable pharmacodynamic effect. Denervation with upregulation of acetylcholine receptors may increase resistance to nondepolarizing neuromuscular blocking drugs. This resistance may outlast the patients’ sensitivity to succinylcholine. On the other hand, muscle weakness and decreased muscle mass may be associated with increased sensitivity. Careful titration, continual monitoring and use of the lowest necessary dose, represent prudent management principles. The nerve twitch should be monitored, if possible, on an unaffected extremity so that factors such as increased resistance to neuromuscular blocking drugs will not lead to unintended overdoses.
Reference:
Dorotta IR, Schubert A. Multiple sclerosis and anesthetic implications. Current Opinion in Anaesthesiology 2002, 15:365-370.
Miller’s Anesthesia, 6th ed. 2005, Churchill Livingston, Chapter 13 ñ Pharmacology of Muscle Relaxants and their antagonists ñ demyelinating diseases.
A definitive diagnosis of Alzheimerís disease can only be made by which of the following tests or exams?
A. Psychiatric examination
B. Neurologic examination
C. CNS imaging studies (CT scan, MRI, and PET scan) D. Examination of brain tissue at autopsy
Answer: D
Rationale:
The dementing illness of Alzheimer’s disease is insidious in its onset, very gradual in its progression, and ultimately fatal. It manifests itself as changes in memory and daily functioning and is characterized by anterograde amnesia, cognitive decline and dementia which lead to the patient’s inability to participate in self-care, disruptions in speech, and swallowing abnormalities. Seven stages of disease progression have been developed to better define the progression nature of the cognitive deterioration. A presumptive clinical diagnosis of Alzheimer’s disease is obtained by identifying the patient’s clinical symptoms and comparing them with a set of known criteria. Patients generally undergo complete physical, neurologic and psychiatric examinations. An attempt is made to rule out treatable illnesses such as Parkinson’s disease, drug toxicity, metabolic diseases, dietary deficiency, cerebrovascular accident, and CNS infective diseases (e.g. syphilis or HIV). Common diagnostic tools include Mini Mental State Examination, CBC, serum electrolytes, liver function tests, cholesterol, serum lipids, vitamin B12 and folate, thyroid function tests, urinalysis, chest x-ray, ECG, EEG, and CNS imaging studies. Though each of these tests, when taken as a whole, can lead identification of Alzheimer’s disease through a process of elimination, the diagnosis can only be made with certainty at time of the patient’s death when the brain tissue is examined for intra -cellular fl-amyloid plaques, extracellular fl- amyloid and intracellular neurofibrillary tangles of tau protein in the entorhinal cortex, hippocampus, basal forebrain, amygdale and parietotemporal cortex ñ areas related to memory, learning, language, and emotional behavior.
Reference:
Braak H, Braak E. Neuropathological staging of Alzheimer-related changes. Acta Neuropathol 1991; 82:239.
Braak H, Braak E. Evolution of neuronal changes in the course of Alzheimerís disease. J Neural Transm Suppl 1998; 53:127.
Haaroutunian V, Perl DP, Purohid DP, et al. Regional distribution of neuritic plaques in the nondemented elderly and subjects with very mild Alzheimer disease. Arch Neurol 1998; 55:1185
A 65 year-old male underwent general anesthesia for mandible fracture repair one day ago. His family notes weakness of his right arm and slurring of speech over the last 30 minutes. Which of the following studies should be initially performed? A. Lumbar puncture B. Carotid arteriogram C. Carotid doppler D. Noncontrast head CT
Answer: D
Rationale:
Brain imaging remains a required component of the emergency assessment of patients with suspected stroke. Both CT and MRI are options for imaging the brain, but for most cases and at most institutions, CT remains the most practical initial brain imaging test. Head CT will determine if the cause of arm weakness and slurred speech is a CVA and whether it is hemorrhagic or ischemic. Ischemic strokes comprise approximately 80% of strokes. Thrombolytic therapy is ideally initiated within 3 hours of the event to decrease the long- term disability of the individual.
Most patients with stroke do not need an examination of cerebrospinal fluid. The yield of brain imaging is very high for detection of intracranial hemorrhage. The clinical course of subarachnoid hemorrhage or acute central nervous system infections usually is distinct from that of ischemic stroke. Examination of the cerebrospinal fluid may be indicated for evaluation of a patient with a stroke that may be secondary to an infectious illness.
In addition to CT and MR angiography, transcranial Doppler ultrasonography, carotid duplex sonography, and catheter angiography have been used to detect intracranial or extracranial vessel abnormalities, but head CT would be the initial test for imaging.
Reference:
Kokko, J., Stein, S., The Emory University Comprehensive Board Review in Internal Medicine. McGraw-Hill. New York, 2000, p711-712.
Adams H, et al. Guidelines for the Early Management of Adults with Ischemic Stroke; Stroke 2007; 38: 1655.
A 32 year-old patient with rheumatoid arthritis presents for treatment of partially erupted tooth #32 with pericoronitis. The patient takes methotrexate. Which medication should be avoided in the post-operative management of this individual? A. Hydrocodone B. Codeine C. Tylenol D. Ibuprofen
Answer: D
Rationale:
Methotrexate is used for the management of rheumatoid arthritis. The mechanism of action of methotrexate is that it is a folate antimetabolite that inhibits DNA synthesis. Methotrexate irreversibly binds to dihydrofolate reductase, resulting in inhibition of or purine and thymidylic acid synthesis.
Methotrexate has side-effects which include bone marrow suppression, aplastic anemia, and GI toxicity with concomitant administration of NSAIDs. Penicillins may increase methotrexate concentrations due to a reduction in renal tubular secretion. Tylenol and opioids may be administered to this patient.
Severe, sometimes fatal, toxicity (including hematologic and GI toxicity) has occurred following administration of a NSAID (e.g., indomethacin, ketoprofen) concomitantly with methotrexate (particularly with high-dose therapy) in patients with various malignant neoplasms, psoriasis, or rheumatoid arthritis. The toxicity was associated with elevated and prolonged serum concentrations of methotrexate. The exact mechanism of the interaction remains to be established, but it has been suggested that NSAIDs may inhibit renal elimination of methotrexate, possibly by decreasing renal perfusion via inhibition of renal prostaglandin synthesis or by competing for renal elimination.
NSAIDs should be avoided in patients receiving relatively high dosages of methotrexate (e.g., those used in the treatment of neoplastic disease). The risk of concomitant low-dose, intermittent (e.g., 5-15 mg weekly) methotrexate therapy and NSAIDs has not been fully elucidated, but the drugs have been used concomitantly in many patients receiving methotrexate for the management of rheumatoid arthritis. However, in clinical studies in which the drugs were used concomitantly, the patients often were monitored closely and were receiving relatively stable dosages of NSAIDs; in addition, those with conditions that might predispose to methotrexate toxicity generally were excluded from the studies. NSAIDs should be used with caution in patients receiving low-dose methotrexate regimens such as those employed in the management of rheumatoid arthritis, and the possibility of increased and prolonged serum methotrexate concentrations and resultant toxicity should be considered. Although intermittent regimens also are used in the management of psoriasis, methotrexate dosages in such regimens usually are higher than those used in the management of rheumatoid arthritis and therefore are more likely to result in toxicity during concomitant NSAID therapy; serious toxicity, including at least one death, has been reported in several patients with psoriasis receiving combined therapy with the drugs. Further study is needed to evaluate the interaction between NSAIDs and methotrexate.
Reference:
AHFS Drug Information, McEvoy, American Society of Health-System Pharmacists, Inc., 2007, Methotrexate
Eye examination of a trauma patient in the emergency department reveals one pupil to be fixed and dilated, with that same eye deviated laterally and downward, with ptosis of the eyelid. Which of the following cranial nerves is injured? A. Optic (II) B. Oculomotor (III) C. Trochlear (IV) D. Abducens (VI)
Answer: B
Rationale:
The oculomotor nerve has been injured in this case. This nerve supplies motor function to all of the extraocular muscles, except the lateral rectus (supplied by the abducens nerve) and the superior oblique (supplied by the trochlear nerve). Thus the only nerves functioning have caused a downward and lateral gaze in the affected eye. The oculomotor nerve also supplies motor function to the levator palpebrae superioris. Loss of this function has caused ptosis of the eyelid. Parasympathetic fibers carried by cranial nerve III from the ciliary ganglion to the pupillary sphincter cause pupillary constriction. Injury to these fibers causes dilation of the affected pupil.
Reference:
Seidel et al: Mosby’s Guide to Physical Examination, 6th ed., Mosby Elsevier, St. Louis, MO; 2006; p.308.
Romanes: Cunningham’s Manual of Practical Anatomy, Oxford Medical Publications, Oxford; 2006; p.113.
The mechanism of action of diazepam (Valium) when treating status epilepticus occurs via a GABA mediated inhibition of what ion? A. Calcium B. Potassium C. Sodium D. Chloride
Answer: D
Rationale:
During seizures, extracellular potassium and intracellular calcium concentrations increase and contribute to the overall excitability of the epileptic neuronal aggregate. During the seizure itself, neurons are tonically depolarized and fire continuously in a sustained, high- frequency discharge (corresponding to the tonic phase of the seizure). The seizure ends as phasic repolarizations interrupt the continuous firing pattern (the cellular correlate of the clinical clonic phase) and gradually restore membrane potentials to normal or to a temporary hyperpolarized state (postictal depression).The benzodiazepines and barbiturates exert their anticonvulsant effect by enhancing postsynaptic γ-aminobutyric acid (GABA)- mediated inhibition through an effect on the chloride ionophore. Phenytoin and carbamazepine are effective anticonvulsants because they produce a use-dependent block of sodium channels, limiting the capability of neurons to fire at high-frequency rates.
Reference:
Goldman: Cecil Textbook of Medicine, 22nd ed.; 2004, WB Saunders, Chapter 426, Status Epilepticus
Drug Information Handbook for Dentistry, 12th ed. Wynn, Meiller, Crossley. Lexi-comp, 2006, p. 455.
Hornerís syndrome results from damage to which nerve fibers? A. Sympathetic fibers to the pupil B. Parasympathetic fibers to the pupil C. Optic nerve D. Oculomotor nerve
Answer: A
Rationale:
A unilateral small pupil is commonly due to underactivity of the ipsilateral sympathetic pathways. Miosis is commonly associated with ptosis (lip droop) due to sympathetic denervation of the tarsal muscle and facial anhidrosis (loss of sweating). This combination is known as Horner’s syndrome. It may be due to a lesion of the hypothalamus, brain stem, cervical spinal cord, or sympathetic fibers to the pupil. Horner’s syndrome may be the first sign of an apical lung tumor (Pancoast tumor) or may occur in diseases affecting the carotid artery. The Pancoast tumor causes compression on the spinal cord at C8-T1. The sympathetic fibers to the superior cervical ganglion arise from the T1 level.
Reference:
Andeoli, Carpenter, et al. Cecil Essentials of Medicine, 7th ed. Saunders Elsevier, Philadelphia, 2007 p. 1080
Goetz: Textbook of Clinical Neurology, 2nd ed. Saunders Elsevier 2003, Chapter 21 ñ Autonomic nervous system < Pupils < Horner’s syndrome, and Chapter 15 ñ Strength and Reflexes > Lower Motor Neuron Syndromes
Which of the following are the vitamin-K dependent clotting factors? A. III, VII, IX, X B. II, VII, IX, X C. III, VIII, IX, XII D. II, VIII, IX, XII
Answer: B
Rationale:
There are 5 factors produced in the liver: II, V, VII, IX, and X. Of these, four are vitamin- K dependent II, VII, IX, and X. Vitamin K is required for gamma-carboxylation of the factors. Virtually all clotting factors are produced in the liver. Factor VIII is made in several tissues, including the liver as well as the glomerular and tubular epithelial cells in the kidney. Warfarin interferes with hepatic synthesis of vitamin K-dependent clotting factors. The PT (Prothrombin time)/INR (International normalized ratio) are both measures of the extrinsic pathway in the clotting cascade.
Reference:
Abubaker AO: Oral and Maxillofacial Surgery Secrets. Hanley & Belfus, Inc., Philadelphia, PA, 2001; Page 130
Andeoli, Carpenter, et al. Cecil Essentials of Medicine, 7th ed. Saunders Elsevier, Philadelphia, 2007 p. 532-538
Tierney LM: 2005 Curent Medical Diagnosis and Treatment. McGraw-Hill, Inc, New York, New York; 2005; Page 656
