Neo Valves Flashcards
ReKap
Rheumatic fever is a non-suppurative sequela of pharyngitis with group A β-hemolytic streptococci (Streptococcus pyogenes).
Among all medically important Streptococcus species, Streptococcus pyogenes is the only bacitracin-sensitive organism.
It is also catalase (-), coagulase (-), β-hemolytic and pyrrolidonyl arylamidase (PYR) (+).
Analysis
The correct answer is C. This case is classic for rheumatic fever, which is diagnosed using the Jones criteria (2 major criteria or 1 major and 2 minor criteria) in the presence of a previous history of Streptococcus infection. Note: These criteria are only applicable for patients presenting with an initial episode of acute rheumatic fever. Different criteria are used to diagnose recurrent episodes. The Jones criteria are listed below:
Major criteria:
Migratory polyarthritis
Carditis and valvulitis (mitral regurgitation and eventually stenosis)
Subcutaneous nodules on the back of the wrist, the outside elbow, and the front of the knees
Erythema marginatum
Sydenham chorea
Minor criteria:
Fever
Arthralgia: Joint pain without swelling
Increased erythrocyte sedimentation rate
Electrocardiogram abnormalities: a prolonged PR interval
Immunologically, rheumatic fever is a type II hypersensitivity reaction in which anti-streptococcal antibodies cross-react with normal heart tissue resulting in an autoimmune myocarditis. Rheumatic fever is a sequela that may occur two to four weeks following an untreated infection with group A streptococci (Streptococcus pyogenes). S. pyogenes is differentiated from the other beta-hemolytic streptococci by its sensitivity to the antibiotic bacitracin.
The catalase test (choice A) is used to differentiate staphylococci from streptococci. Staphylococci are catalase-positive; streptococci are catalase-negative. Streptococcus pyogenes is catalase-negative. Staphylococci do not cause rheumatic fever.
The coagulase test (choice B) is used to differentiate Staphylococcus aureus from the other Staphylococcus species. S. aureus is coagulase-positive; the others are coagulase-negative. Staphylococci are not causative agents of rheumatic fever.
Sensitivity to novobiocin (choice D) is used to differentiate Staphylococcus saprophyticus (resistant) from Staphylococcus epidermidis (sensitive). Staphylococci are not causative agents of rheumatic fever.
Sensitivity to Optochin (choice E) is used to differentiate Streptococcus pneumoniae (sensitive) from Viridans streptococci (resistant). These microbes do not cause rheumatic fever.
The following table summarizes the major species of both Staphylococcus and Streptococcus and their identifying features:
ReKap
Classic acute infective endocarditis:
IV drug user
Tricuspid insufficiency
Most common associated bacteria is Staphylococcus aureus
Empiric antibiotic treatment should be started
Analysis
The correct answer is C. This patient is presenting with signs and symptoms of acute infective endocarditis (IE), which is most commonly (>30% of total cases) caused by Staphylococcus aureus.
Although the clinical characteristics of IE can vary, most patients present with a febrile illness lasting several days to 2 weeks. This illness is often accompanied by a variety of nonspecific signs and symptoms such as chills, weakness, dyspnea, cough, arthralgia, diarrhea, and abdominal pain. The patient’s cardiac exam shows a holosystolic murmur heard best at the lower left sternal border, a sign of tricuspid valve regurgitation. Intravenous drug users are especially prone to infections of the right heart. Injection drugs may be contaminated with bacteria, fungi, minerals (e.g. talc, added as a cutting agent) and other foreign materials that are carried via systemic veins to the right heart, where they may damage the valve leaflet epithelium and leave them susceptible to developing acute IE. Endocarditis secondarily leads to valve insufficiency. The acute endocarditis in IV drug abusers can affect previously normal valves.
Other clinical signs of IE include Osler nodes (purplish or erythematous subcutaneous papules or nodules on the pads of the fingers and toes), Janeway lesions (hemorrhagic, painless plaques on the palms and soles), and petechiae (small, erythematous, painless, hemorrhagic lesions that may appear anywhere). The diagnosis of IE is dependent on positive blood cultures and echocardiographic evidence of “valvular vegetations” and/or valvular injury.
Enterococci (choice A) cause a minority of cases of native valve endocarditis but are not usually involved in endocarditis associated with intravenous drug abuse. They cause subacute bacterial endocarditis. Bacteremia arises from urogenital or hepatobiliary tract sources. Another association worth knowing is that Streptococcus gallolyticus endocarditis should prompt a colonoscopy to search for possible colon cancer.
Gram-negative normal oral flora in the HACEK group (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae) (choice B) cause subacute bacterial endocarditis (non-intravenous drug users). Blood cultures can be negative in cases of endocarditis due to HACEK organisms.
Staphylococcus epidermidis (choice D) and Staphylococcus aureus are common causes of prosthetic valve endocarditis shortly after surgery.
Viridans streptococci (choice E) is the most common cause of subacute bacterial endocarditis. They are normal flora organisms in the oropharynx and can easily access the bloodstream. Recall that subacute endocarditis, e.g., caused by viridans streptococci, has a predilection for previously damaged valves, sometimes following invasive dental procedures.
ReKap
Major criteria for the diagnosis of rheumatic fever include pancarditis, arthritis, subcutaneous nodules, chorea, and erythema marginatum.
Rheumatic fever is caused by a type II hypersensitivity reaction.
Antibodies against group A Streptococcus interact with body tissues, e.g., myocardium and joints, and inflammation of those tissues follow.
Analysis
The correct answer is B. This patient has rheumatic fever, which is a type II hypersensitivity reaction to infection with Streptococcus pyogenes (also known as Group A Streptococcus).
Rheumatic fever:
Characterized by pancarditis, arthritis, subcutaneous nodules, chorea, and erythema marginatum.
Infection with group A Streptococcus (GAS) often precedes the onset of the disease by 2-3 weeks, typically as pharyngitis.
GAS incites the production of antistreptococcal antibodies, which cross-react with antigens of the heart, dermis, joints, etc., triggering an acute inflammatory response that eventually resolves.
Patients often suffer permanent sequelae, such as valvular heart disease.
Other examples of type II hypersensitivity-mediated diseases (i.e., involving autoantibodies) include Graves disease, in which the autoantibodies stimulate thyroid hormone production by binding thyroid-stimulating hormone (TSH) receptors, and myasthenia gravis, in which the autoantibodies interfere with cholinergic neuromuscular transmission by binding nicotinic receptors.
Type I hypersensitivity (choice A) is mediated by IgE. Antigens bind IgE on the surface of mast cells and trigger the release of inflammatory mediators such as histamine and heparin. Activation of the arachidonic acid cascade causes the production of prostaglandins and leukotrienes. Asthma and urticaria are classic examples.
Contrast direct antibody interaction with immune complex formation and deposition. In type III hypersensitivity (choice C), immune complexes (antigen-antibody protein complexes) form in the blood and deposit in tissues, especially within vascular beds. The glomeruli of children are especially sensitive to immune complex deposition after GAS infection, so-called acute post-streptococcal glomerulonephritis. Serum sickness and systemic lupus erythematosus are other examples of type III hypersensitivity-mediated diseases.
Diseases caused by type IV hypersensitivity (choice D) (also known as delayed-type or cell-mediated hypersensitivity) are due to inappropriate helper T cell activation of phagocytes and direct killing by CD8+ cytotoxic T cells. One example of this reaction is pancreatic beta-cell death in type I diabetes.
The following table summarizes the classification of immunologic diseases.
ReKap
Aortic stenosis: harsh, “diamond-shaped” (crescendo-decrescendo) mid-systolic murmur that radiates to the neck.
Aortic stenosis in older patients is most commonly due to calcification of the valves.
Bicuspid valves may also undergo calcification, but are seen in much younger patients.
Analysis
The correct answer is D. The gross picture shows a stenotic bicuspid aortic valve, which typically is associated with a mid-systolic murmur that radiates to the neck.
Bicuspid aortic valves are the most common cause of aortic stenosis in younger patients (senile calcification of the valvular cusps is the most common cause in older patients). They tend to be clinically silent in childhood or adolescence, but the valve gradually undergoes progressive calcification and stenosis. Narrowing of valve orifice promotes compensatory left ventricular concentric hypertrophy and an increase in left ventricular pressure (see figure) to maintain forward flow. By the third or fourth decade, stenosis presents as dyspnea (from pulmonary edema), chest pain (ischemia from increased myocardial demand), syncope (cerebral hypoperfusion due to inadequate blood flow through the stenotic valve), narrow pulse pressure, and a slowly rising pulse, also known as pulsus parvus et tardus.
On chest auscultation, aortic stenosis manifests with a harsh systolic murmur (SM), which is “diamond-shaped,” i.e., it is more intense in mid systole and is sometimes preceded by an opening (ejection) click. Radiation of the murmur is along the vessels that branch off the aortic arch, and thus the murmur is audible in the left cervical region.
The Wigger’s Diagram for aortic stenosis is shown. Note that in mid-systole, the ventricular pressure is much higher than the aortic pressure. This abnormality occurs because increased pressure is required by the left ventricle to overcome the extra resistance created by the stenotic aortic valve.
A continuous machinery-like murmur (choice A) is a classic finding in patent ductus arteriosus. The murmur is associated with shunting of blood from the aorta to the pulmonary artery throughout systole and diastole.
A diastolic murmur beginning with a snap (choice B) is highly characteristic of mitral valve stenosis. The snapping sound is due to the sudden opening of the rigid (fibrotic and calcified) leaflets. The murmur has a low-pitched, rumbling character and is localized near the apex. Rheumatic disease and infective endocarditis are the two most common causes.
Mitral valve prolapse is the most common cause of mid-systolic click (choice C). Regurgitation occurs in the most severe cases and gives rise to a systolic murmur following the click. The abnormal sound is due to a “floppy” valve, which is pushed back into the atrium (prolapse) by the force of the left ventricular contraction.
A pansystolic murmur that is loudest at the apex (choice E) is most likely due to mitral valve regurgitation. This differs from the systolic murmur of aortic stenosis because of its pansystolic duration, its location near the apex, and the absence of accompanying clicks. Rheumatic disease and infective endocarditis are the most common underlying etiologies.
ReKap
Acute bacterial endocarditis in intravenous drug users is most frequently caused by Staphylococcus aureus.
There is right-sided valvular damage, mainly involving the tricuspid valve.
Analysis
The correct answer is A. This patient has acute infective endocarditis secondary to intravenous drug use. Valvular vegetations can cause septic emboli, including pulmonary emboli, which would show up as patchy infiltrates in both lungs. Staphylococcus aureus is the most common cause. Bacteria are introduced into the venous system from the skin, then they colonize and damage the tricuspid valve. Left-sided acute bacterial endocarditis can also occur as a result of septicemia and dissemination from lung emboli. Peripheral lesions of infective endocarditis can include petechiae, splinter hemorrhages, Janeway lesions, Osler nodes, and Roth spots.
Tricuspid valve regurgitation is described as a holosystolic, high-pitched “blowing murmur” heard at the tricuspid area and radiating to the left or right sternal border. The choice of empiric therapy should cover methicillin-susceptible and resistant staphylococci, streptococci, and enterococci. Vancomycin is an appropriate choice for initial therapy in most patients.
The endocarditis associated with congenital heart disease (choice B) typically involves either damaged valves or atrial- or ventricular septal defects. The tricuspid valve is not particularly vulnerable.
Rheumatic fever (choice C) most commonly damages the mitral and aortic valves. Tricuspid damage is usually less severe and seen only when the mitral and aortic valves are heavily involved.
Rheumatoid arthritis (choice D) is not associated with bacterial endocarditis. However, it is associated with the development of pericarditis.
Systemic lupus erythematosus (choice E) can produce small, aseptic vegetations on the ventricular and atrial surfaces of the mitral valve (Libman-Sacks endocarditis) as well as pericarditis.
A 34-year-old man who uses intravenous drugs comes to the emergency department because of frequent, severe headaches evolving over the last few days. While in the hospital, the patient begins to develop an altered mental status. His temperature is 38.9°C (102°F), pulse is 78/min, respirations are 14/min, and blood pressure is 80/45 mm Hg. Physical examination shows conjunctival hemorrhages, a new systolic heart murmur heard best in the left lower sternal border, and painful, red, indurated lesions on his hands, fingers, and toes. A photograph of his hand is shown. Blood cultures return the next day with positive growth. A CT scan of the head demonstrates a ring-enhancing lesion located at the gray-white matter junction. Laboratory studies show the patient is HIV negative. Which of the following organisms is the most likely cause of this patient’s disorder?
A. Herpesvirus
B. Mycobacterium tuberculosis
C. Staphylococcus aureus
D. Streptococcus pneumoniae
E. Toxoplasma gondii
ReKap
Acute bacterial endocarditis in an intravenous drug user is often caused by Staphylococcus aureus.
It may produce large, penetrating valvular lesions seen on echocardiography.
These vegetations can embolize to the brain, causing brain abscesses that can appear as ring-enhancing lesions on a CT scan.
Analysis
The correct answer is C. This patient has acute infective endocarditis. The presence of the Duke criteria aids in the diagnosis of the condition. Major criteria include positive blood cultures and evidence of endocardial involvement (e.g., an echocardiogram positive for cardiac lesions or new onset of murmur). Minor criteria include predisposing factors, fever, immunologic phenomena (e.g., glomerulonephritis, Osler’s nodes (as seen in our patient; see image), Roth spots, and positive rheumatoid factor), and vascular phenomena (e.g., evidence of septic embolism, brain thromboemboli, conjunctival hemorrhages (as seen in our patient), Janeway lesions, and splinter hemorrhages).
More specifically, our patient presents with acute bacterial endocarditis, which evolves over several days with spiking fevers and rapid clinical deterioration. This is more commonly seen in intravenous drug users and the most common organism involved is Staphylococcus aureus. This form of endocarditis can involve native valves. IV drug use can cause right-sided acute bacterial endocarditis, but left-sided acute bacterial endocarditis can also occur (cause of arterial septic emboli). In contrast, subacute bacterial endocarditis progresses more slowly with milder symptoms and almost always involves previously damaged valves. Subacute bacterial endocarditis usually involves infection by Streptococcus viridans, oral flora that can enter the bloodstream after a dental procedure or gum bleeding.
The ring-enhancing lesion noted on the CT scan of our patient is consistent with a brain abscess, a known complication of bacterial endocarditis. It occurs when cardiac vegetations fragment and release septic emboli. Emboli to the brain (including tumor metastases) commonly present at the gray-white junction due to its high vascularity.
Herpesvirus (choice A) can cause encephalitis but is not a cause of vegetative endocarditis. Herpes encephalitis usually affects the temporal lobe and can produce hemorrhage. Patients can present with seizures. A CT scan would show a hypodense lesion.
Mycobacterium tuberculosis (choice B) can cause brain masses and dissemination to other organs from miliary tuberculosis, but it does not usually cause endocarditis.
Streptococcus pneumoniae (choice D) can cause acute pyogenic meningitis (a common cause of adult meningitis) but does not usually cause endocarditis.
Toxoplasmosis is caused by the parasite Toxoplasma gondii (choice E) in immunocompromised patients (e.g., AIDS, CD4 count <100). It may cause ring-enhancing lesions in the brain on CT scan. However, it is very unlikely in this patient because he is HIV-negative.
ReKap
Acute bacterial endocarditis:
Commonly caused by Staphylococcus aureus, a gram-positive, catalase-positive, coagulase-positive coccus that grows in grapelike clusters.
Most common in intravenous drug users.
Commonly affects the right heart, specifically the tricuspid valve.
Pulmonary abscess is a complication of right-sided infective endocarditis.
Analysis
The correct answer is C. This patient has developed acute infective endocarditis as a result of his intravenous drug use. Septic emboli thrown off from the tricuspid valve typically lodge in the pulmonary circulation where they may cause a pulmonary abscess.
Staphylococcus aureus is the most likely pathogen, given the description of gram-positive, coagulase-positive cocci in clusters.
S. aureus endocarditis:
The pathogen is typically introduced via venous access in IV drug users.
Bacterial vegetations most commonly form on the right side of the heart, specifically the tricuspid valve.
Symptoms include prolonged, high fever, fatigue, constitutional symptoms, and malaise.
Physical examination may reveal a murmur of tricuspid regurgitation (as noted in our patient).
Left-sided vegetations cause mitral valve regurgitation and septic emboli in the skin, Janeway lesions, and eye (Roth spots).
Immune complex deposition occurs with Osler nodes.
Other common causes of endocarditis include:
Streptococcus viridans, which produces a more subacute form of endocarditis with milder fevers and tends to affect already damaged valves.
Staphylococcus epidermidis endocarditis, which usually occurs in patients with prosthetic valves rather than native valves.
Streptococcus bovis, which is typically introduced into the systemic circulation in patients with colon cancer, thus endocarditis caused by this agent may require a follow-up colonoscopy.
Enterococcal endocarditis, which is classically produced following GI/GU procedures.
Mitral stenosis (choice A) is classically associated with rheumatic fever due to chronic damage to the mitral valve. Rheumatic fever typically presents in younger patients after a Group A streptococcal infection of the pharynx. This is an unlikely occurrence since the introduction of antibiotic therapy for streptococcal pharyngitis. In addition, our patient has a distinctive murmur of tricuspid regurgitation rather than that of mitral stenosis.
Prerenal azotemia (choice B), splenic abscess (choice D), and stroke (choice E) are associated with left-sided IE. They occur as a result of septic emboli released into the systemic circulation that can lodge in the renal vasculature, (producing renal infarcts), in the spleen (producing an abscess), or in the cerebral vessels, (producing a stroke). Typically, however, S. aureus endocarditis in an IV drug abuser will affect the tricuspid valve, rather than the mitral or aortic valves.
ReKap
Think of acute infective endocarditis and tricuspid valve vegetations in a patient who is an IV drug user.
Classic findings in acute infective endocarditis include fever and a new heart murmur.
The most common organism responsible for acute infective endocarditis is Staphylococcus aureus.
Analysis
The correct answer is B. This patient presents as extremely ill with a high fever and a new systolic murmur. Given the rapid clinical course (over a few days), this is likely a case of acute infective endocarditis. The diagnosis of this condition must be confirmed by blood cultures, which determine bacterial antibiotic sensitivity. The causative agents of infective endocarditis differ depending on host factors.
Staphylococcus aureus (commonly present on the skin) is the most frequent etiologic agent of acute infective endocarditis in intravenous drug users.
Key points:
S. aureus can affect native, undamaged valves and frequently affects the tricuspid valve.
The patient’s holosystolic murmur is consistent with tricuspid regurgitation, most likely due to valve vegetations.
Septic emboli from right-sided endocarditis may produce pulmonary abscesses and infarcts.
S. aureus-related endocarditis follows an acute course and may lead to death within a few days.
Fungal organisms, such as Candida albicans (choice A), may cause infective endocarditis in severely immunosuppressed patients, such as those with AIDS and T-cell deficiencies. In these cases, surgical intervention is indicated.
S. epidermidis (choice C) and other coagulase-negative staphylococci tend to produce subacute endocarditis in recipients of prosthetic valves. This type of endocarditis usually requires surgical intervention. S.epidermidis infection can be seen with IV drug users but is less common than S. aureus.
Streptococcus bovis (choice D) is a rare cause of subacute endocarditis. It is found in the normal GI tract flora of 5-16% of adults. Typically, S. bovis endocarditis is more common in men and in the elderly. S. bovis is associated with colorectal cancer (especially the S. gallolyticus subtype).
Viridans streptococci (choice E) are the most frequent agents causing subacute endocarditis in previously damaged valves (e.g., rheumatic disease) or in congenitally abnormal valves.
ReKap
Bicuspid aortic valve is a congenital anomaly, which in most cases, remains asymptomatic, but increases the risk of aortic stenosis later in life.
The most common abnormal sound on physical examination is a systolic click. If stenosis is present, a systolic ejection murmur at the right upper sternal border may radiate to the carotids.
Analysis
The correct answer is A. Isolated bicuspid aortic valve is a very common congenital anomaly and may cause a range of symptoms. It may be completely asymptomatic or may cause modest aortic valve stenosis (AS). AS usually produces symptoms of dyspnea on exertion, lightheadedness, or dizziness on exertion.
The most common abnormal sound heard with a bicuspid aortic valve has been described as a systolic ejection click. If AS is present, it can produce an ejection murmur at the upper right sternal border, often with radiations into the carotids as the stenosis worsens. A bicuspid aortic valve is the most common cause of AS in young patients. For older patients, calcification of the valve is the most common cause of AS (note: heart sounds can be heard best with headphones).
Secundum type atrial septal defect (choice B) is a noncyanotic defect because it produces a left-to-right shunt postnatally. If there is a large shunt, this can result in an ejection murmur of the pulmonic valve because of the volume overload to the right side of the heart. This patient presents with an aortic murmur, not a pulmonic murmur, which would be best heard at the left upper sternal border.
Uncorrected patent ductus arteriosus (choice C) produces a continuous (“machine-like”) murmur and cyanosis later in childhood (Eisenmenger syndrome) due to volume and pressure overload of the pulmonary circulation.
Persistent truncus arteriosus (choice D) produces early cyanosis. Truncus arteriosus is associated in some cases with 22q11 deletions (DiGeorge syndrome, velocardiofacial syndrome).
Tricuspid atresia (choice E), which is usually accompanied by an atrial septal defect, produces early cyanosis. The heart may be normal-sized or enlarged; right atrial enlargement can be seen.
ReKap
Although pharyngitis caused by GAS can resolve without treatment, there is the risk of developing RHD due to molecular mimicry between GAS antigens and native heart tissue.
Chronic RHD can lead to the development of mitral stenosis and consequent left atrial enlargement.
Left atrial enlargement predisposes to the development of atrial fibrillation, which is characterized on ECG with non-distinct P waves.
Analysis
The correct answer is C. The patient is presenting with left atrial enlargement as a result of mitral stenosis. Atrial enlargement distorts normal electrical conduction pathways and can result in atrial fibrillation (A-fib), which appears as non-distinct P waves on an ECG.
The patient’s presenting symptoms and the physical exam findings are consistent with a diagnosis of rheumatic heart disease (RHD). His childhood episodes of “sore throat” were most likely pharyngitis caused by Streptococcus pyogenes (group A streptococcus; GAS) which, when left untreated, can lead to RHD. The pathogenesis of RHD is due to molecular mimicry of GAS antigens that induce an autoimmune response against native heart tissue.
Chronic RHD can result in mitral stenosis and a compensatory increase in left atrial pressure. The latter causes left atrial enlargement. The pressure increase is transmitted back into the pulmonary vasculature causing vascular engorgement and symptoms such as dyspnea on exertion and hemoptysis. Eventually, pulmonary hypertension can lead to right heart failure with symptoms such as peripheral edema and hepatomegaly.
Left atrial enlargement from RHD-associated mitral stenosis predisposes to the development A-fib. The classic finding on the physical exam for atrial fibrillation is an irregularly irregular heart rhythm. On ECG, atrial fibrillation is characterized by lack of discernible P waves or P-P interval, and an irregularly irregular R-R interval. Due to increased stasis of blood in the left atrium, A-fib predisposes to thrombus formation. Thus, patients with A-fib may need long-term anticoagulation with agents such as vitamin K antagonists, direct-thrombin inhibitors, or factor X inhibitors.
Alternating QRS amplitudes (choice A) are termed electrical alternans. The most common cause of electrical alternans is pericardial effusion. RHD would not typically cause pericardial effusion. In addition, patients with pericardial effusion would present with sinus tachycardia.
A delta wave (choice B) manifests as slurred upstroke of the QRS complex and a shortened PR interval. It is highly specific for Wolf-Parkinson-White syndrome (WPW). Most patients with WPW are asymptomatic, although some patients can present with palpitations, arrhythmias, and/or syncope. Dyspnea on exertion and hemoptysis due to pulmonary engorgement would be extremely unusual symptoms for patients with WPW.
PR prolongation (choice D) is associated with atrioventricular (AV) block. Etiologies for AV block include ischemia (e.g., post-myocardial infarction), Lyme disease, and certain drugs (e.g., beta-blockers, digoxin, and calcium-channel blockers). First-degree AV block is generally asymptomatic, but second- or third-degree AV block can cause syncope, dizziness, and/or arrhythmia.
QT prolongation (choice E) is associated with delayed myocardial repolarization. The etiology of long-QT syndrome (LQTS) can be either congenital or acquired. Some acquired etiologies include drugs (e.g., antipsychotics, class IA and III antiarrhythmics), hypokalemia, hypomagnesemia, and hypocalcemia. Patients with prolonged QT interval can be asymptomatic or present with palpitations, syncope, and/or sudden cardiac arrest, most notably from torsades de pointes.
ReKap
Acute rheumatic fever is a sequela of group A streptococcal pharyngitis.
Acute rheumatic fever can lead to long-term damage of the heart valves, resulting in thickened, blunted cardiac valve leaflets, often with fibrous bridging between valve leaflets and calcification.
Prior episodes of rheumatic fever is the most common cause of mitral stenosis.
Damage to heart valves most often involves mitral and/or aortic valves.
Analysis
The correct answer is B. Fibrous bridging between thickened, calcified leaflets in combination with the murmur and history of pharyngitis should point to a history of acute rheumatic fever as a child and, now, resultant mitral stenosis.
Prior rheumatic fever is the most common cause of mitral stenosis. Although this patient is currently asymptomatic, exercise intolerance, cough, and atrial fibrillation can eventually develop. Acute rheumatic fever is a multisystem inflammatory disease that can follow group A streptococcal pharyngitis.
Rheumatic fever is diagnosed on the basis of 2 major Jones criteria (migratory polyarthritis, erythema marginatum, Sydenham chorea, subcutaneous nodules, carditis) or 1 major criterion and 2 minor criteria (previous rheumatic fever, fever, arthralgias, prolonged P-R interval, elevated ESR, leukocytosis, elevated C-reactive protein).
The heart is a primary target of this disease and may be damaged sufficiently to develop permanent sequelae. The most important of these sequelae is chronic rheumatic heart disease with valvular damage. The damage most often involves the mitral and/or aortic valves.
Healing and scarring of the affected mitral valve in our patient result in thickened, blunted cardiac valve leaflets, often with fibrous bridging between valve leaflets and calcification, frequently takes on a “fish-mouth” or “buttonhole” appearance with stenotic morphology. On auscultation, mitral stenosis presents with a loud S1 (representing abrupt closure of valve leaflets that are still wide apart at the end of diastole), an opening snap (abrupt halting of leaflet motion seen in a stenotic valve), and a diastolic murmur heard best over the apex (turbulence created by a high-velocity blood jet impacting the contents of the ventricle).
Associate ballooning of valve leaflets (choice A) with mitral valve prolapse. This has no relationship to rheumatic fever. It often presents in young, asymptomatic women with a mid-systolic click.
Associate irregular, beadlike calcifications on the annulus (choice C) with calcification of the mitral annulus, commonly seen in elderly individuals. This has no relationship to rheumatic fever.
Associate large vegetations and leaflet perforation (choice D) with acute bacterial endocarditis, which usually involves healthy, rather than previously damaged, valves.
Associate tiny vegetations along the line of closure (choice E) with marantic (nonbacterial thrombotic) endocarditis, most typically seen at autopsy in patients who died after a protracted illness, such as cancer.
ReKap
Dystrophic calcification of the aortic valve is the most common cause of aortic stenosis in older patients.
A systolic crescendo-decrescendo murmur can be heard in the right upper sternal border and can radiate to the carotids.
Aortic stenosis increases afterload, thereby causing concentric left ventricular hypertrophy.
Eventually, the left ventricle dilates with volume overload, leading to congestive heart failure.
Analysis
Note: heart sounds can be heard best with headphones.
The correct answer is A. This patient’s physical examination shows a crescendo-decrescendo systolic murmur heard best at the right upper sternal border, which is a classic presentation for aortic stenosis. Key points:
Typically affects patients older than 65 years.
Dystrophic calcification of the aortic valve leaflets from senile degenerative changes.
Increased afterload causes initial concentric hypertrophy of the left ventricle.
Subsequent dilatation through volume loading can progress to heart failure with associated symptoms (shortness of breath, paroxysmal nocturnal dyspnea, leg swelling, etc.).
Dilatation of the mitral annulus (choice B) may occur in cases of left ventricular dilation, producing mitral regurgitation. A typical finding in mitral regurgitation is a holosystolic high-pitched murmur auscultated at the cardiac apex.
Aortic dissection (choice C) presents with acute chest pain typically radiating to the back. It must be differentiated from chest pain of cardiac ischemic origin (i.e., angina or myocardial infarction). Key points:
Murmur of aortic regurgitation due to dilation of the valvular annulus or long-standing hypertension.
Can occur with Marfan syndrome and cystic medial degeneration (fragmentation of elastic laminae with the formation of cystic spaces and deposition of a myxoid matrix).
Bicuspid aortic valves (choice D) are congenitally acquired and may present with symptoms and signs of aortic stenosis. Key points:
Rare compared to senile calcification of the aortic valve.
Manifests clinically in middle age (4th decade).
May be inherited or associated with Turner syndrome.
Vegetations on the valve leaflets (choice E) can be seen when the aortic valve is affected by infectious endocarditis.
Two forms: acute or subacute infectious endocarditis.
Bacterial growth on the valve surface promotes acute inflammation and fibrin-rich vegetations.
May lead to perforation and rupture of valve leaflets, resulting in aortic insufficiency (i.e., regurgitation), not stenosis.
Aortic regurgitation is a high-pitched early diastolic decrescendo murmur.
Echocardiogram is very sensitive for demonstrating aortic vegetations and structural abnormalities
ReKap
The murmur of mitral regurgitation is a holosystolic apical murmur radiating to the axilla and often accompanied by a thrill.
Wide splitting of S2 may occur because of early closure of the aortic valve.
A major cause of mitral regurgitation is rheumatic heart disease.
Analysis
The correct answer is C. The murmur heard in the media file has the characteristics of mitral regurgitation: a holosystolic apical murmur that radiates to the axilla and is often accompanied by a thrill. Wide splitting of S2 may occur because of early closure of the aortic valve (much of the left ventricular volume escapes backwards through the mitral valve).
Symptoms of mitral regurgitation include dyspnea, fatigue, and left ventricular failure. During systole, an incompetent mitral valve results in backflow of blood from the left ventricle into the left atrium (causing a murmur). This produces two effects: first, increasing left atrial pressure causes backup of fluid into the pulmonary vasculature, resulting in pulmonary hypertension. High pressure in pulmonary vessels causes extravasation of serous fluid into the lung bases, producing pulmonary edema; lung crackles, dyspnea, and elevated respiratory rate support this conclusion. Second, volume overload of the left ventricle also occurs because of increased left atrial volumes (from regurgitation). This initially is a compensatory response to maintain cardiac output, but over long periods of time, it results in remodeling and left ventricular failure.
Mitral regurgitation is a common heart valvular disease. It may result from a number of different conditions; however, rheumatic heart disease remains a major cause worldwide. Approximately 20% of patients with rheumatic fever will develop valvular heart disease, including mitral regurgitation and mitral stenosis. Mitral regurgitation results from severe valvular injury. Mitral stenosis usually develops years after the initial episode. Other findings in acute rheumatic fever include Sydenham chorea (characterized by jerking movements of arms and legs, difficulty writing, involuntary grimacing, etc.), erythema marginatum rash (pink ring-shaped rashes on trunk and limbs), polyarticular arthritis, myocarditis, and fever. This patient presents with some of these findings.
In aortic regurgitation (choice A), the area and the characteristics of the murmur differ from mitral regurgitation. A diastolic decrescendo murmur is the most typical finding and classically occurs at the left sternal border.
In aortic stenosis (choice B), there is a systolic ejection murmur in the right upper sternal border that (1) is usually accompanied by thrill, (2) is harsh in quality, and (3) radiates to the carotids. Major causes include age-related calcification and bicuspid aortic valve.
Mitral stenosis (choice D) is high on the differential diagnosis list, because it is most commonly caused by rheumatic fever. Mitral stenosis can be distinguished from mitral regurgitation by the characteristics of the murmur. In mitral stenosis, the murmur is diastolic, as opposed to the systolic murmur heard in our patient. Two additional auscultatory findings include a loud S1 and an opening snap that follows S2. Mitral stenosis can produce symptoms of pulmonary hypertension, as well as atrial fibrillation (due to significant left atrial dilation).
Tricuspid regurgitation (choice E) produces a high-pitched pansystolic murmur (loudest in the fourth intercostal space of the parasternal region). This murmur is usually increased during inspiration (which accentuates all right-sided murmurs) and is reduced in intensity during a Valsalva maneuver (high intrathoracic pressure reduces right-sided venous return). A short, early diastolic flow rumble may be present because of increased flow across the tricuspid valve. Causes include staphylococcus endocarditis and carcinoid syndrome. Patients with tricuspid regurgitation would not present with pulmonary hypertension.
A 33-year-old woman comes to the physician for a follow-up examination. She has a history of intermittent fever and joint pains. She also says that she is very sensitive to the sun and gets a red rash on her face and arms when she is exposed to the sun for short periods of time. She denies a history of prior sore throat, infection, leg pain or swelling, or chest pain. Her temperature is 37.4°C (99.3°F), pulse is 78/min, respirations are 14/min, and blood pressure is 136/80 mm Hg. Physical examination of the joints shows no abnormalities. Painless oral ulcers are seen on oral examination. This patient is at increased risk for which of the following cardiac conditions?
A. Hemorrhagic pericarditis
B. Infective endocarditis
C. Libman-Sacks endocarditis
D. Mitral valve prolapse
E. Myocardial fibrosis
F. Rheumatic fever
ReKap
Libman-Sacks endocarditis is a characteristic cardiac manifestation of SLE.
The mitral and aortic valves are commonly involved, with small, granular vegetations seen on both sides of the leaflets.
The resultant fibrotic process leads to distortion of the valve leaflets and eventually to insufficiency or stenosis of the valves.
Analysis
The correct answer is C. For the diagnosis of systemic lupus erythematosus (SLE), a patient must meet four of 11 criteria; these include malar rash, photosensitivity, anemia, hematologic disorders, and arthritis. Libman-Sacks endocarditis can affect patients with SLE.
In Libman-Sacks endocarditis, small, granular, sterile vegetations consisting of fibrin develop on either side of the leaflets of the mitral and aortic valves. Fragments of vegetations may detach, resulting in embolic sequelae (e.g., stroke, splenic infarction, myocardial infarction). Eventually, vegetations heal by the organization of fibrin and subsequent fibrosis, leading to the distortion of valve leaflets and resultant insufficiency or stenosis. The pathogenesis is unclear but is probably related to a thrombotic diathesis.
Other important sequelae of SLE include glomerulopathy (diffuse proliferative or membranous) and serositis (pleuritis, serous or fibrinous pericarditis, etc.). Anti-dsDNA, anti-Smith, and anti-nuclear antibodies are important serum markers for SLE.
Hemorrhagic pericarditis (choice A) is usually a consequence of tuberculosis or the metastatic spread of cancer to the pericardium. An inflammatory exudate containing blood accumulates in the pericardial sac, producing pain and a characteristic auscultatory phenomenon known as a pericardial rub. This is different from cardiac tamponade, in which there is overt bleeding into the pericardial sac and a lack of inflammation, e.g., aortic dissection, puncture/knife wound. SLE is associated instead with serous or fibrinous pericarditis, which also manifests with chest pain and a pericardial rub.
Infective endocarditis (choice B):
Prevalent in patients with damaged valves (Streptococcus viridans) or prosthetic valves (Staphylococcus epidermidis) and native valves in intravenous drug abusers (Staphylococcus aureus and S. epidermis).
Associated with the formation of bulky, friable vegetations that consist of masses of fibrin, neutrophils, and bacteria.
Causes extensive destruction of valve leaflets and may release fragments into the bloodstream, with resultant septic embolism.
Patients may present with fever, a non-photosensitive rash, septic emboli, and arthralgias.
There is no association between SLE and mitral valve prolapse (choice D), which is usually asymptomatic. The valvular abnormality occurs in 2 to 3% of the general population.
Associated with Marfan syndrome.
Can have a systolic murmur with a mid-systolic click.
Complications include sudden death, thromboembolism, and mitral regurgitation.
Myocardial fibrosis (choice E) may develop in progressive systemic sclerosis, an autoimmune condition characterized by extensive fibrosis in many organs, especially the skin, lungs, and gastrointestinal tract. The heart is involved in 30% of cases. Complications include arrhythmias or heart failure.
Rheumatic fever (choice F) typically presents in children or young adults who were not treated for a Streptococcal throat infection. Manifestations include:
Migratory arthritis, fever, pancarditis (myocarditis, endocarditis, and pericarditis), chorea, erythema marginatum (pink, ring-shaped rash on trunk and limbs), and subcutaneous nodules.
Classic late manifestation is mitral stenosis.
ReKap
Acute infective endocarditis leads to the formation of bulky and friable vegetations on the valvular leaflets.
Staphylococcus aureus is a common pathogen in those who use IV drugs.
Complications of infective endocarditis include valve damage, septic embolization, local spread of infection, metastatic infection, and immune-mediated organ damage (e.g., glomerulonephritis).
Analysis
The correct answer is A. Our patient presents with the classic symptoms and signs of acute infective endocarditis, including fever, malaise, chills, and a systolic murmur on physical examination. Acute infective endocarditis leads to the formation of bulky and friable vegetations on the valvular leaflets, such as those in this picture. The vegetations are composed of fibrin, neutrophils, and colonies of bacteria that cause erosion of underlying valvular structures. Fragments of infected vegetations may detach and cause pulmonary or systemic (brain, lungs, coronary arteries, spleen) septic embolism. Our patient presents with worsening respiratory distress, which is likely due to a pulmonary abscess from septic emboli. Smaller embolic signs of endocarditis include retinal hemorrhages (Roth Spots) and Janeway lesions (painless macules on palms/soles). Non-embolic complications include heart failure (from valvular complications) and immune-mediated organ damage (glomerulonephritis, Osler nodes [nodules on the fingers or toes that are pinkish in color]).
Another important part of our patient’s history is the IV drug abuse (IVDA). Patients who engage in IVDA classically have infective endocarditis due to Staphylococcus aureus, which is highly virulent. The tricuspid valve is most commonly affected in IVDA-associated endocarditis, which increases the probability of septic embolization to the lungs. S. aureus endocarditis can also affect native valves versus other types of endocarditis (Streptococcus viridans) that affect previously damaged heart valves (subacute bacterial endocarditis).
Carcinoid heart disease (choice B) is caused by serotonin-producing carcinoid tumors. Carcinoid syndrome may result from primary carcinoid lung tumors or liver metastases from primary midgut neuroendocrine tumors. Patients classically present with right-sided murmurs (tricuspid regurgitation and pulmonary stenosis) and right ventricular endocardial fibrosis. Inactivation of serotonin and other vasoactive substances occurs in the lung, thus the left atrium and ventricles are not affected. Plaque-like deposits on valvular leaflets are a characteristic gross finding.
Libman-Sacks endocarditis (choice C) is a non-infective form of endocarditis associated with systemic lupus erythematosus (SLE). The vegetations are small and regularly aligned along the valvular margins. Interestingly, vegetations can occur on both sides of the valve in these patients.
Nonbacterial thrombotic endocarditis (choice D) was previously known as marantic endocarditis, being associated with debilitating conditions such as disseminated neoplasms and chronic infection/inflammation. Increased coagulability is probably the underlying pathogenesis. The lesions are small vegetations comprised of fibrin and platelets, similar to Libman-Sacks endocarditis.
Q fever endocarditis (choice E) is a blood-culture negative endocarditis. The diagnosis is based on serology or polymerase chain reaction (PCR) for Coxiella burnetii, which does not grow on conventional blood cultures. This form of endocarditis classically occurs in patients with previously damaged valves or who are immunocompromised. Patients with Q fever also present in a more subacute manner with low-grade fevers.
ReKap
Acute infective endocarditis leads to the formation of bulky and friable vegetations on the valvular leaflets.
Staphylococcus aureus is a common pathogen in those who use IV drugs.
Complications of infective endocarditis include valve damage, septic embolization, local spread of infection, metastatic infection, and immune-mediated organ damage (e.g., glomerulonephritis).
Analysis
The correct answer is A. Our patient presents with the classic symptoms and signs of acute infective endocarditis, including fever, malaise, chills, and a systolic murmur on physical examination. Acute infective endocarditis leads to the formation of bulky and friable vegetations on the valvular leaflets, such as those in this picture. The vegetations are composed of fibrin, neutrophils, and colonies of bacteria that cause erosion of underlying valvular structures. Fragments of infected vegetations may detach and cause pulmonary or systemic (brain, lungs, coronary arteries, spleen) septic embolism. Our patient presents with worsening respiratory distress, which is likely due to a pulmonary abscess from septic emboli. Smaller embolic signs of endocarditis include retinal hemorrhages (Roth Spots) and Janeway lesions (painless macules on palms/soles). Non-embolic complications include heart failure (from valvular complications) and immune-mediated organ damage (glomerulonephritis, Osler nodes [nodules on the fingers or toes that are pinkish in color]).
Another important part of our patient’s history is the IV drug abuse (IVDA). Patients who engage in IVDA classically have infective endocarditis due to Staphylococcus aureus, which is highly virulent. The tricuspid valve is most commonly affected in IVDA-associated endocarditis, which increases the probability of septic embolization to the lungs. S. aureus endocarditis can also affect native valves versus other types of endocarditis (Streptococcus viridans) that affect previously damaged heart valves (subacute bacterial endocarditis).
Carcinoid heart disease (choice B) is caused by serotonin-producing carcinoid tumors. Carcinoid syndrome may result from primary carcinoid lung tumors or liver metastases from primary midgut neuroendocrine tumors. Patients classically present with right-sided murmurs (tricuspid regurgitation and pulmonary stenosis) and right ventricular endocardial fibrosis. Inactivation of serotonin and other vasoactive substances occurs in the lung, thus the left atrium and ventricles are not affected. Plaque-like deposits on valvular leaflets are a characteristic gross finding.
Libman-Sacks endocarditis (choice C) is a non-infective form of endocarditis associated with systemic lupus erythematosus (SLE). The vegetations are small and regularly aligned along the valvular margins. Interestingly, vegetations can occur on both sides of the valve in these patients.
Nonbacterial thrombotic endocarditis (choice D) was previously known as marantic endocarditis, being associated with debilitating conditions such as disseminated neoplasms and chronic infection/inflammation. Increased coagulability is probably the underlying pathogenesis. The lesions are small vegetations comprised of fibrin and platelets, similar to Libman-Sacks endocarditis.
Q fever endocarditis (choice E) is a blood-culture negative endocarditis. The diagnosis is based on serology or polymerase chain reaction (PCR) for Coxiella burnetii, which does not grow on conventional blood cultures. This form of endocarditis classically occurs in patients with previously damaged valves or who are immunocompromised. Patients with Q fever also present in a more subacute manner with low-grade fevers.
ReKap
The most common cause of acute bacterial endocarditis in people who use intravenous drugs is Staphylococcus aureus.
S. aureus is a gram-positive, catalase-positive, coagulase-positive coccus. It is a normal flora organism on the skin.
Analysis
The correct answer is D. This patient is exhibiting the classic signs of acute bacterial endocarditis (rapid onset, days to weeks of fever, petechiae on the soft palate, splinter hemorrhages). Painful subcutaneous nodules on the palms or soles (Osler nodes) may form, or painless macules or nodules (Janeway lesions) may be found. Retinal hemorrhages with pale centers (Roth spots) may also be observed. In those who use intravenous drugs, Staphylococcus aureus is the most common causative agent and is the most common normal flora organism on the skin of these patients. Although the tricuspid valve is commonly affected in people who use IV drugs, overall, left-sided endocarditis (mitral and aortic valves) is more prevalent than right-sided endocarditis (IV drug users and non-IV drug users), which is seen in our patient as a mitral valve regurgitation murmur. Left-sided endocarditis contributes to the septic emboli (petechiae and hemorrhages) seen in our patient.
This is an image showing some of the findings in infective endocarditis, including Roth spots, splinter hemorrhages, and septic emboli.
The correct answer choice is the classic description of this species. Catalase positivity distinguishes the genus Staphylococcus from Streptococcus, and Staphylococcus aureus is the only coagulase-positive member of its genus. The diagnosis of endocarditis is generally based on positive blood culture results, often in combination with a systolic murmur on physical examination, and echocardiography confirming valvular vegetations and/or damage.
Acute bacterial endocarditis, such as this patient has, often occurs in the context of intravenous drug use or can be nosocomially acquired from catheters or other intravascular devices. Pathogens for acute endocarditis are often normal skin flora, such as Staphylococcus or Streptococcus. Gram-negative bacteria, such as Pseudomonas, are infrequent causes. Subacute bacterial endocarditis, on the other hand, typically occurs with previously damaged valves or prosthetic valves and may have a more indolent course, with low-grade fever, anorexia, weight loss, malaise, headache, myalgias, night sweats, shortness of breath, cough, or joint pains.
Antibodies to p24 capsid antigen (choice A) would be likely in someone who uses IV drugs and is HIV-positive rather than a patient with endocarditis.
Trichinella spiralis (choice B) can cause splinter hemorrhages during the larval migration period, but would not be a likely cause for the formation of petechiae in the conjunctivae and palate.
Staphylococcus epidermidis is a coagulase-negative, catalase-positive, gram-positive coccus (choice C). It is a common cause of subacute endocarditis in those who use IV drugs and can cause subacute endocarditis in patients with prosthetic valves. The symptoms described in this vignette are much more consistent with acute endocarditis than subacute endocarditis.
Enterococci are gamma-hemolytic, gram-positive cocci that grow on bile-esculin agar (choice E). Enterococci can cause subacute bacterial endocarditis, chiefly after urologic instrumentation in men, rather than in association with intravenous drug use.
Streptococcus viridans is an alpha-hemolytic, optochin-resistant, gram-positive coccus (choice F). It is implicated in subacute bacterial endocarditis after oral or dental treatments but would not be the most likely agent in this case, given the acute nature of this patient’s presentation.
Streptococcus pneumoniae is an alpha-hemolytic, optochin-sensitive, gram-positive coccus (choice G) that produces cough and chest pain, but would be an unlikely cause of bacterial endocarditis.
ReKap
Aortic stenosis:
A crescendo-decrescendo, systolic murmur.
A low pulse pressure, sustained apical impulse, delayed pulse peak, and reduced or delayed A2.
An ejection click and S4 are possible.
Analysis
The correct answer is B. The arrows are pointing to the aortic valve. The murmur heard in aortic stenosis is a diamond-shaped (crescendo-decrescendo) systolic murmur. An ejection click, as well as an S4, may be heard. Other physical findings may include low pulse pressure, sustained apical impulse, delayed pulse peak, and reduced or delayed A2.
Grade 1 is so faint that it can be heard only with special effort. It is not expected that medical students are able to hear grade 1 murmurs.
Grade 2 is faint but is immediately audible.
Grade 3 is moderately loud.
Grade 4 is very loud.
Grade 5 is extremely loud and is audible with one edge of the stethoscope touching the chest wall.
Grade 6 is so loud that it is audible with the stethoscope just removed from contact with the chest wall.
In general, murmurs with an intensity of grade 4 or higher are accompanied by a palpable thrill.
A continuous murmur (“machinery murmur”) that is loudest at S2 (choice A) is characteristic of left-to-right shunting through a patent ductus arteriosus. The presentation and intensity of the murmur depends on the magnitude of the pressure gradient between aorta and pulmonary artery. As pulmonary hypertension develops and pulmonary arterial pressure approaches aortic pressure, the diastolic portion of the murmur becomes briefer and may disappear. Arteriovenous fistulas can also produce continuous murmurs.
A decrescendo diastolic murmur (choice C) would be expected in aortic regurgitation and pulmonic regurgitation.
A diastolic rumble (choice D) best heard in the left lateral decubitus position is characteristic of mitral stenosis. The stenotic valve typically also produces a characteristic opening snap.
A holosystolic murmur that is best heard over the apex (choice E) is found in chronic mitral regurgitation. An audible S3 may be noted also.
ReKap
An incompetent aortic valve does not close properly at the beginning of diastole.
As a result, during diastole there is turbulent retrograde flow from the aorta into the left ventricle, resulting in a high-pitched, blowing, early diastolic murmur.
Analysis
The correct answer is B. This angiogram demonstrates the , from its origin to the thoracic segment, along with its associated branches. The lateral swellings indicated by the arrows correspond to the three cusps of the aortic valve. If the aortic valve is insufficient, blood flows back from the aorta into the left ventricle (LV) during diastole, a pathophysiologic phenomenon described as aortic regurgitation. The backflow results from higher pressures in the aorta during diastole (normal is 80 mm Hg) compared to the left ventricle (normal is 10 mm Hg). This turbulent blood flow results in a high-pitched, blowing, early-diastolic murmur, most intense at the left sternal border. Maneuvers that increase systemic vascular resistance (and subsequently aortic diastolic pressure), such as handgrip and squatting, will increase the intensity of this murmur.
Other findings in these patients include a widened pulse pressure and “water-hammer pulse.” These occur because, during diastole, retrograde blood flow into the LV through the incompetent aortic valve drops aortic diastolic pressure. The backward movement of blood adds to the preload for the next contraction, however, thereby increasing the force of contraction and generating a higher peak systolic pressure (Frank-Starling mechanism). The combination of lower diastolic pressure and greater systolic pressure creates the widened pulse pressure and accentuated pulses.
Causes of aortic insufficiency include a dilated aortic root (secondary to hypertension, syphilis, Takayasu arteritis, Marfan syndrome), bicuspid aortic valve, endocarditis, valve leaflet abnormalities, and rheumatic fever.
A continuous systolic-diastolic (machinery-like) murmur (choice A) is highly characteristic of patent ductus arteriosus. Abnormal persistence of a patent ductus arteriosus into adulthood allows constant shunting of blood from a high-pressure system (aorta) to a low-pressure system (pulmonary artery) during both phases of cardiac contraction, thus resulting in a continuous systolic-diastolic murmur.
The designation of friction rub (choice C) suggests its origin. This auscultatory abnormality is a rubbing sound arising from the friction of the parietal and visceral leaflets of a serosal membrane. Friction rubs are associated with inflammatory processes involving the pericardium or pleura (pericarditis and pleuritis), which result in the accumulation of a fibrin-rich exudate on the visceral surface. These patients present with sharp chest pain that is worsened with inspiration and is better with leaning forwards.
A mid-systolic click followed by a murmur (choice D) is due to mitral valve prolapse, a common (but usually asymptomatic) abnormality of the mitral valve. Myxomatous degeneration of the mitral leaflets is the underlying organic alteration, which leads to a “floppy” mitral valve. This floppy valve prolapses into the left atrium during systolic contraction, resulting in the characteristic click. If regurgitation is also present, the click is followed by a murmur and can result in symptoms of heart failure. Mitral valve prolapse can be inherited in an autosomal dominant manner and is associated with Marfan syndrome or Ehler-Danlos syndrome.
A systolic ejection murmur radiating to the neck (choice E) along the carotids may result from stenosis of the aortic valve. This is usually caused by age-related (60’s and 70’s) calcification of the aortic cusps, which produces a narrowed ostium. Other causes include rheumatic fever and a bicuspid aortic valve (associated with Turner syndrome). The resulting murmur radiates to the neck because the sound wave is transported along the direction of blood flow. Other findings in aortic stenosis include pulsus tardus et parvus (pulse is weak and delayed).
