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.