Infective Endocarditis — MCQs

10 questions

What is the optimal timing for administering antibiotic prophylaxis before surgery?

A child presented at 10 weeks with recurrent episode of pneumonia and failure to thrive. X-ray shows cardiomegaly & pulmonary plethora. What is the diagnosis?

A 32-year-old woman is supposed to undergo tooth extraction surgery. Physical examination is unremarkable, and she has a blood pressure of 126/84 mm Hg and regular pulse of 72/min. She takes no medications. Which of the following cardiac conditions would warrant antibiotic prophylaxis to prevent infective endocarditis in this patient?

Which of the following is a minor criterion for the diagnosis of acute rheumatic fever?

A 6-year-old with congenital heart disease presents with fever, new-onset murmur, and petechiae. Blood cultures are pending, but initial Gram stain shows Gram-positive cocci. What is the most appropriate initial intervention?

A 7 year old child with a known history of rheumatic heart disease presents with a 3 weeks history of fever with palpitations. Most likely cause is:

True about a 1-year-old child with PDA is –

Infective endocarditis is not seen in –

A 32 year old man presents with history of recurrent jaundice over the previous decade. Family gives history of the patient having episodes of facial grimacing. Which one of the following is a clinical clue to the diagnosis?

Q10

Flat vegetations in valve pockets due to deposition on previously normal valve surfaces are characteristic of:

Infective Endocarditis Indian Medical PG Practice Questions and MCQs

Question 1: What is the optimal timing for administering antibiotic prophylaxis before surgery?

A. Immediately before induction of anesthesia
B. 30-60 minutes before incision (Correct Answer)
C. 2-3 hours before surgery
D. Immediately after surgery

Explanation: ***30-60 minutes before incision*** - This is the **optimal timing** recommended by WHO, CDC, and major surgical guidelines for most commonly used prophylactic antibiotics (cefazolin, cefuroxime). - Ensures **peak tissue and serum concentrations** are achieved at the time of incision, providing maximum protection against surgical site infections. - Based on **pharmacokinetic principles**: the antibiotic must be present at bactericidal concentrations in tissues when bacterial contamination occurs. - Studies show this timing significantly reduces surgical site infection rates compared to other timings. *Immediately before induction of anesthesia* - While acceptable in some protocols, this may be too early if there is a delay between induction and incision. - Could result in **declining antibiotic levels** by the time the incision is made, especially for antibiotics with shorter half-lives. *2-3 hours before surgery* - This is **too early** for most antibiotics. - Tissue levels may have already **declined below therapeutic concentrations** by the time of incision. - Does not provide adequate protection during the critical period of bacterial contamination. *Immediately after surgery* - This is **treatment, not prophylaxis**. - Offers **no preventive benefit** against intraoperative contamination. - By this time, bacteria introduced during surgery have already adhered to tissues and begun forming biofilms.

Question 2: A child presented at 10 weeks with recurrent episode of pneumonia and failure to thrive. X-ray shows cardiomegaly & pulmonary plethora. What is the diagnosis?

A. VSD (Correct Answer)
B. TOF
C. Patent foramen ovale
D. ASD

Explanation: ***VSD*** - **Ventricular septal defect (VSD)** is the most common cause of this presentation in early infancy (symptoms typically appear at **6-10 weeks** of age). - Large VSDs cause significant **left-to-right shunt** leading to pulmonary overcirculation, resulting in **recurrent pneumonia** and **failure to thrive**. - **Cardiomegaly** (due to volume overload of left atrium and ventricle) and **pulmonary plethora** (increased pulmonary vascular markings) on X-ray are classic findings. - The infant may also present with tachypnea, feeding difficulties, and poor weight gain. *TOF* - **Tetralogy of Fallot (TOF)** is a **cyanotic heart defect** with right-to-left shunt, presenting with cyanosis and hypoxic spells, not recurrent pneumonia. - X-ray shows **boot-shaped heart** and **pulmonary oligemia** (decreased pulmonary vascular markings), not pulmonary plethora. - Does not typically cause failure to thrive in the same manner as acyanotic left-to-right shunt lesions. *Patent foramen ovale* - A **patent foramen ovale (PFO)** is a normal variant in infants and typically remains **asymptomatic**. - Does not cause significant hemodynamic shunting in the absence of elevated right atrial pressure. - Does not cause **cardiomegaly**, **pulmonary plethora**, recurrent pneumonia, or failure to thrive. *ASD* - An **atrial septal defect (ASD)** also causes left-to-right shunt with pulmonary plethora, but the shunt develops **gradually** over time. - ASD typically presents **later in childhood or adulthood** with milder symptoms (fatigue, exercise intolerance) due to lower pressure gradient across atria. - **Recurrent pneumonia and failure to thrive at 10 weeks** are uncommon with isolated ASD, as the hemodynamic changes are less pronounced in early infancy compared to VSD. - When symptomatic in infancy, large ASDs present later (around 6 months to 1 year) rather than at 10 weeks.

Question 3: A 32-year-old woman is supposed to undergo tooth extraction surgery. Physical examination is unremarkable, and she has a blood pressure of 126/84 mm Hg and regular pulse of 72/min. She takes no medications. Which of the following cardiac conditions would warrant antibiotic prophylaxis to prevent infective endocarditis in this patient?

A. Hypertrophic obstructive cardiomyopathy (HOCM)
B. Mitral regurgitation
C. Past history of infective endocarditis (Correct Answer)
D. Ventricular septal defect (VSD)
E. Implantable cardioverter defibrillator (ICD)

Explanation: ***Past history of infective endocarditis*** - A **history of infective endocarditis** is a definite indication for **antibiotic prophylaxis** before dental procedures that involve manipulation of gingival tissue, periapical region of teeth, or perforation of the oral mucosa due to the high risk of recurrence. - This condition creates a predisposition to subsequent episodes of endocarditis, even with minor bacteremia. *Hypertrophic obstructive cardiomyopathy (HOCM)* - While HOCM is a significant cardiac condition, it is **no longer an indication** for routine infective endocarditis prophylaxis in the absence of other high-risk features like a prosthetic valve. - Current guidelines have narrowed the criteria for prophylaxis due to the low absolute risk and potential for side effects from antibiotics. *Mitral regurgitation* - **Mitral valve regurgitation**, in the absence of a prosthetic valve or a previous history of endocarditis, generally **does not warrant antibiotic prophylaxis** for routine dental procedures. - Only specific types of valvular heart disease with high risk (e.g., prosthetic valves, certain congenital heart diseases) require prophylaxis. *Ventricular septal defect (VSD)* - **Most ventricular septal defects do not require prophylaxis**. Only **unrepaired cyanotic VSD** or **repaired VSD with residual defects adjacent to prosthetic material** would warrant prophylaxis. - Completely repaired VSDs without residual defects do not require prophylaxis after the initial 6 months post-repair. - In this case, with an unremarkable physical examination and normal vital signs, there is no indication of cyanotic heart disease. *Implantable cardioverter defibrillator (ICD)* - An **implantable cardioverter defibrillator (ICD)** itself is a device and does not inherently increase the risk for infective endocarditis to warrant prophylaxis for dental procedures. - The risk of infection is primarily associated with the device insertion procedure itself, not with subsequent dental interventions.

Question 4: Which of the following is a minor criterion for the diagnosis of acute rheumatic fever?

A. Subcutaneous nodules
B. Carditis
C. Chorea
D. Fever (Correct Answer)

Explanation: ***Fever*** - **Fever** is a minor diagnostic criterion for **acute rheumatic fever** (ARF), indicating systemic inflammation [1]. - While non-specific, its presence alongside other criteria supports the diagnosis, particularly in the context of recent streptococcal infection. *Subcutaneous nodules* - **Subcutaneous nodules** are a **major criterion** for ARF, typically firm, painless lumps found over bony prominences. - Their presence indicates more severe, chronic inflammation in ARF. *Carditis* - **Carditis** is a **major criterion** for ARF, referring to inflammation of the heart, which can affect the pericardium, myocardium, or endocardium [1]. - It is the most serious manifestation of ARF, as it can lead to permanent **rheumatic heart disease** [2]. *Chorea* - **Chorea** (specifically **Sydenham chorea**) is a **major criterion** for ARF, characterized by involuntary, jerky movements, often presenting late in the disease course [1]. - It results from inflammation affecting the basal ganglia.

Question 5: A 6-year-old with congenital heart disease presents with fever, new-onset murmur, and petechiae. Blood cultures are pending, but initial Gram stain shows Gram-positive cocci. What is the most appropriate initial intervention?

A. Schedule for urgent valve replacement
B. Administer high-dose steroids
C. Start broad-spectrum antibiotics (Correct Answer)
D. Wait for susceptibility testing

Explanation: ***Start broad-spectrum antibiotics*** - The presentation of **fever**, **new-onset murmur**, **petechiae**, and **Gram-positive cocci** in a patient with **congenital heart disease** is highly suggestive of **infective endocarditis**. - Prompt initiation of **broad-spectrum antibiotics** is crucial to prevent further damage to the heart valves and systemic complications while awaiting definitive culture results. *Schedule for urgent valve replacement* - **Valve replacement** is a definitive treatment for severe valvular damage but is typically considered after initial medical management has failed or in cases of severe complications like heart failure or recurrent emboli. - It is not the initial intervention for suspected infective endocarditis. *Administer high-dose steroids* - **Steroids** are anti-inflammatory but are not indicated in the treatment of active bacterial infections like endocarditis. - Administering steroids could potentially worsen the infection by suppressing the immune response. *Wait for susceptibility testing* - **Waiting for susceptibility testing** to initiate treatment would delay critical care, allowing the infection to progress and increasing morbidity and mortality. - Initial treatment should be empiric, and antibiotics can be narrowed once susceptibility results are available.

Question 6: A 7 year old child with a known history of rheumatic heart disease presents with a 3 weeks history of fever with palpitations. Most likely cause is:

A. Kawasaki's disease
B. Staphylococcal endocarditis (Correct Answer)
C. None of the options
D. Collagen vascular disease

Explanation: **Staphylococcal endocarditis** - Children with **rheumatic heart disease** are at increased risk for **infective endocarditis** due to pre-existing valvular damage. - The symptoms of **fever** and **palpitations** over 3 weeks in a child with a predisposing cardiac condition are highly suggestive of subacute bacterial endocarditis, with *Staphylococcus* being a common pathogen. *Kawasaki's disease* - **Kawasaki's disease** is characterized by fever for at least 5 days, along with specific criteria such as **conjunctivitis**, **oral changes**, **rash**, and **lymphadenopathy**, which are not mentioned here. - Although it can cause cardiac complications like **coronary artery aneurysms**, it does not typically present with palpitations in the context of pre-existing rheumatic heart disease. *None of the options* - This option is incorrect because **Staphylococcal endocarditis** is a highly plausible diagnosis given the clinical presentation. - The combination of **rheumatic heart disease**, prolonged fever, and palpitations strongly points towards a specific cardiac infection. *Collagen vascular disease* - **Collagen vascular diseases** like SLE or juvenile idiopathic arthritis can present with fever, but **palpitations** in a child with pre-existing **rheumatic heart disease** is less specific for these conditions. - These diseases typically have other systemic manifestations, such as **arthralgia**, **rash**, or **organ involvement**, which are not described.

Question 7: True about a 1-year-old child with PDA is –

A. Symptoms similar to aortopulmonary window (Correct Answer)
B. Indomethacin may help in closure
C. Chances of spontaneous closure high
D. Endocarditis is rare

Explanation: ***Symptoms similar to aortopulmonary window*** - Both **patent ductus arteriosus (PDA)** and an **aortopulmonary window** involve a connection between the aorta and pulmonary artery, leading to **left-to-right shunting**. - This shunting results in similar clinical presentations, such as a **continuous murmur**, signs of **pulmonary overcirculation**, and potential for **congestive heart failure** and **pulmonary hypertension**. *Indomethacin may help in closure* - **Indomethacin** is effective in closing a PDA, but primarily in **premature infants** and typically within the first few weeks of life. - In a **1-year-old child**, the ductus arteriosus has become muscularized and fibrotic, making medical closure with indomethacin ineffective. *Chances of spontaneous closure high* - The highest probability of **spontaneous closure** of a PDA occurs within the **first few days to weeks of life**. - By **1 year of age**, spontaneous closure is highly unlikely, and the PDA is generally considered to require intervention if it is hemodynamically significant. *Endocarditis is rare* - While uncommon, **infective endocarditis** is a well-recognized complication of an uncorrected PDA. - The turbulent blood flow through the shunt creates an environment conducive to bacterial adherence and infection at the pulmonary artery end of the ductus. - This makes endocarditis a definite risk rather than a rare occurrence, particularly in untreated cases.

Question 8: Infective endocarditis is not seen in –

A. TOF
B. VSD
C. ASD (Correct Answer)
D. MR

Explanation: Atrial septal defect (ASD) is generally considered a low-risk lesion for infective endocarditis because the pressure gradient across the defect is low, leading to less turbulent flow and less endothelial damage. While IE very rarely occurs, it is not common cause for IE. Generally the risk of infective endocarditis in an uncomplicated ASD is comparable to the general population. Tetralogy of Fallot (TOF) is a cyanotic congenital heart disease characterized by four defects (pulmonary stenosis, VSD, overriding aorta, right ventricular hypertrophy) that create turbulent flow, significantly increasing the risk of infective endocarditis. The abnormal anatomy and high flow jets in TOF predispose the heart valves and endocardium to damage, making them fertile ground for bacterial adherence and infection. Ventricular septal defect (VSD) involves an abnormal opening between the ventricles, causing a high-pressure, high-velocity jet of blood flow [1]. This turbulent flow leads to endothelial damage, particularly on the right ventricular side of the defect or the tricuspid valve, creating a nidus for bacterial colonization and infective endocarditis [1]. Mitral regurgitation (MR), especially due to degenerative valve disease or rheumatic heart disease, creates turbulent backward flow into the left atrium during systole. This chronic turbulent flow can cause endothelial injury on the mitral valve leaflets or the atrial wall, increasing the susceptibility to bacterial adherence and subsequent infective endocarditis.

Question 9: A 32 year old man presents with history of recurrent jaundice over the previous decade. Family gives history of the patient having episodes of facial grimacing. Which one of the following is a clinical clue to the diagnosis?

A. Kayser-Fleisher rings in the cornea (Correct Answer)
B. Adenoma sebaceum in the mid face
C. Erythema nodosum on the skin
D. Osler's nodes at the finger tips

Explanation: Detailed clinical features point towards Wilson's disease. ***Kayser-Fleisher rings in the cornea*** - The history of **recurrent jaundice** and **facial grimacing** (likely dystonia/tremors) points towards a **neuropsychiatric disorder** with liver involvement, which is characteristic of **Wilson's disease** [1]. - **Kayser-Fleisher rings** are copper deposits in the Descemet's membrane of the cornea, a pathognomonic sign of Wilson's disease. *Adenoma sebaceum in the mid face* - **Adenoma sebaceum** (facial angiofibromas) is a characteristic skin lesion associated with **tuberous sclerosis complex**, which typically presents with seizures, intellectual disability, and characteristic skin lesions, not recurrent jaundice or facial grimacing indicative of movement disorders. - This condition does not primarily involve recurrent jaundice or movement disorders like facial grimacing. *Erythema nodosum on the skin* - **Erythema nodosum** is an inflammatory condition characterized by painful, red nodules, typically on the shins. - It is often associated with conditions like **sarcoidosis**, inflammatory bowel disease, infections, or drug reactions, and does not commonly present with recurrent jaundice and facial grimacing. *Osler's nodes at the finger tips* - **Osler's nodes** are painful, tender, red or purple lesions found on the fingertips and toes, indicative of **infective endocarditis**. - This symptom is related to immune complex deposition and systemic infection, rather than genetic disorders causing liver disease and neurological dysfunction.

Question 10: Flat vegetations in valve pockets due to deposition on previously normal valve surfaces are characteristic of:

A. Non-bacterial thrombotic endocarditis (NBTE) (Correct Answer)
B. Infective endocarditis
C. Libman-Sacks endocarditis
D. Rheumatic heart disease

Explanation: ***Rheumatic heart disease*** - Characterized by **flat vegetations** on heart valves, known as **Aschoff bodies**, which represent the sequelae of rheumatic fever [1]. - Vegetations in this condition occur due to **non-endothelial attachment**, leading to valve damage and dysfunction . *Rheumatic heart disease* - This is a repeat nd does not provide a different context, hence it is incorrect. - Must include distinguishing clinical features or findings that clearly differentiate it from other listed conditions. *Infective endocarditis* - Characterized by **irregular, bulky vegetations** on valves due to microbial infection, differentiating from the flatter vegetations seen in rheumatic heart disease [1]. - Often associated with **systemic symptoms** such as fever and embolic phenomena, which are not present here. *Non-bacterial thrombotic endocarditis (NBTE)* - Typically presents with **small vegetations** that may also be flat, but are usually found in the context of a malignancy or systemic disease [1]. - These vegetations are primarily **non-infectious**, i.e., not due to current infection, unlike in infective endocarditis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 568. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 566.

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