Do boards expect classic peripheral stigmata (Osler nodes, Janeway lesions) in pediatric IE vignettes?

Rarely; ABFM exams more often cue with fever plus CHD risk factors and a murmur rather than peripheral signs.

Which organisms should I think of first in pediatric IE?

Viridans group streptococci and Staphylococcus aureus; select based on exposure (oral/dental vs healthcare/line).

How does timing after CHD repair affect risk?

Risk is highest within months of surgery, especially with residual defects or prosthetic material (AHA/AAP 2015 guidance).

Is CHF the most common presentation in pediatric IE?

No—fever is most common; CHF is a less frequent complication at presentation.

October 7, 2025

Most Missed Question in FM Boards – Pediatric Infective Endocarditis

By Challenger Corporation · 5 minute read

Why is This the Most Missed Question in Family Medicine Exam Prep This Week?

Key takeaway: In infants and children with congenital heart disease—especially early post-repair with residual defects—prolonged fever plus a persistent murmur should immediately raise suspicion for infective endocarditis as the most likely pathologic process.

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Question – Cyanotic infant endocarditis

An 8-month-old girl presents with fever, malaise, and 15% weight loss over the past 2 months. She was seen by her pediatrician for an ear infection 1 month ago and treated with amoxicillin. Her mother reports that she improved after that, but today she is getting worse.

The patient has a history of tetralogy of Fallot. Surgical correction was performed when the child was 6 months of age; residual ventricular septal defect and right outflow obstruction are still present.

The patient’s vital signs are: heart rate 124 beats/minute; blood pressure 75/50 mm Hg; respiratory rate 28 breaths/minute; and temperature 38.8 °C.

On examination, she is cyanotic, and her lungs are clear, but she has a harsh 3/6 systolic murmur. This is consistent with the residual ventricular septal defect.

Which of the following would be the most common pathologic finding in this patient?

Answers:

A. congestive heart failure (CHF)
B. secondary valvular heart disease
C. tuberculosis (TB)
D. infective endocarditis (IE)

Correct option: D. infective endocarditis (IE)

This item is missed because the stem’s hemodynamics (tachycardia, hypotension), weight loss, and cyanosis tempt examinees toward CHF or chronic infections like TB. But on the boards, the highest-yield signal is recent repair of congenital heart disease with residual defects in an infant with persistent fever—classic for pediatric infective endocarditis. American Heart Association/American Academy of Pediatrics guidance (2015 statement; reaffirmed in practice via 2021 AHA/ADA prophylaxis update) emphasizes congenital heart disease as the dominant predisposing condition for pediatric IE, with risk heightened in the postoperative period and with residual shunts or prosthetic material.

For exam performance, anchor on epidemiology: in children, congenital heart disease accounts for the majority of IE, and fever is by far the most common presenting symptom. Organisms are most often viridans group streptococci and Staphylococcus aureus. Recognizing this pattern prevents overcalling CHF (a complication, not the “most common pathologic finding”) and avoids distractors like TB.

Why This Question Is Frequently Missed

“Most common pathologic finding” is interpreted as a complication (CHF) rather than the underlying disease process (IE).
Weight loss and prolonged fever cue examinees toward TB; the stem’s cardiac risk factors are more determinant on boards.
Underestimation of postoperative IE risk in infants with residual defects after congenital heart surgery.

What the Distractors Indicate

Option	What It Tests / Implies	Why It’s Wrong Here
CHF	Recognizing decompensated heart failure signs	CHF is a possible complication but not the most common pathologic process driving this presentation; fever predominates in pediatric IE.
Secondary valvular heart disease	Thinking of rheumatic/degenerative valvular pathology	Unlikely in an 8-month-old; the key risk is CHD with residual VSD/obstruction, not acquired valvular disease.
TB	Chronic infection causing fever/weight loss	Epidemiology and risk factors don’t fit; no TB exposures are provided, and cardiac history strongly favors IE.
Infective endocarditis	Association of CHD and postoperative period with IE	Correct: CHD (especially with residual defects) is the leading predisposing factor for pediatric IE; fever is the most common symptom.

High-Yield Pearl

In pediatrics, congenital heart disease—particularly post-repair with residual defects—is the top risk factor for infective endocarditis; expect viridans streptococci and Staphylococcus aureus as the leading pathogens.

Core Learning Objectives

1. Recognize congenital heart disease (and recent repair/residual defects or prosthetic material) as the primary predisposing factor for pediatric infective endocarditis and its typical presentations (fever > any single complication).
2. Identify the most common microbiology of pediatric IE and understand timing/context (viridans streptococci with oral sources; Staphylococcus aureus with healthcare exposure/lines; increased risk early post-surgery).

The “Test Trick” at Play

The stem blends nonspecific systemic features (fever, weight loss) with a high-yield risk flag (postoperative CHD with residual VSD). Boards reward pattern recognition: when a child with residual congenital lesions has persistent fever, select infective endocarditis over complications or unrelated chronic infections.

Additional Practice Questions and Remediation for Pediatric Infective Endocarditis

Family Medicine Practice Question 1 - Post-dental fever in repaired VSD

A 7-year-old with a repaired VSD and a small residual shunt develops persistent fever and a new murmur 2 weeks after a dental extraction. Which organism is most likely?

A. Staphylococcus aureus
B. Coagulase-negative staphylococci
C. HACEK organisms
D. Candida albicans
E. Viridans group streptococci

Answer and Remediation

A — Review: S. aureus is common with healthcare exposure or indwelling lines; less linked to dental bacteremia.
B — Review: CoNS are more associated with prosthetic material/device infections, not typical native-valve, dental-related IE.
C — Review: HACEK cause culture-negative or subacute IE but are less common than viridans strep after dental work.
D — Review: Candida IE is rare in immunocompetent children and typically requires major risk factors (TPN, prolonged lines).
E — Correct response!: Oral flora viridans streptococci frequently seed damaged endocardium after dental procedures in CHD.

Family Medicine Practice Question 2 - Central line toddler with fever

A 2-year-old with short-gut syndrome and a tunneled central venous catheter presents with high-grade fevers and a new murmur. Most likely pathogen?

A. Enterococcus faecalis
B. Staphylococcus aureus
C. Viridans group streptococci
D. Streptococcus pneumoniae
E. Bartonella henselae

Answer and Remediation

A — Review: Enterococcus can cause IE but is less common than S. aureus with catheter-related bacteremia.
B — Correct response!: S. aureus is the leading cause with intravascular devices/healthcare exposure in pediatric IE.
C — Review: Viridans strep is more typical with dental sources; less so with central lines.
D — Review: S. pneumoniae is an uncommon cause of IE in children.
E — Review: Bartonella causes culture-negative IE, usually in homeless or cat-exposed adults, far less common in this setting.

Family Medicine Practice Question 3 - Early post-repair tetralogy

A 4-year-old boy with a history of tetralogy of Fallot repaired six months ago presents for a routine follow-up visit. His mother reports he tires more easily during play compared to other children. Physical exam reveals a grade 2/6 systolic murmur at the left upper sternal border and a normal S2. Oxygen saturation is 97% on room air.

Which of the following is the most appropriate next step in management?

A. Begin empiric diuretic therapy for right heart failure
B. Obtain an echocardiogram to assess for residual right ventricular outflow obstruction and pulmonary regurgitation
C. Order a chest CT to evaluate for pulmonary artery stenosis
D. Reassure the mother that mild fatigue is expected after repair
E. Schedule a cardiac MRI to assess for aortic root dilation

Answer and Remediation

Correct Answer: B. Obtain an echocardiogram to assess for residual right ventricular outflow obstruction and pulmonary regurgitation

Explanation:

After surgical repair of tetralogy of Fallot, the most common long-term issues are residual pulmonary stenosis and pulmonary regurgitation, which can lead to right ventricular dilation and dysfunction. An echocardiogram is the appropriate first test for evaluation of new symptoms such as fatigue or exercise intolerance post-repair.

Other options (diuretics, reassurance, advanced imaging) are premature without this essential assessment.

Family Medicine Practice Question 4 - Dental prophylaxis scenario

Which child requires antibiotic prophylaxis for a dental extraction per current recommendations?

A. Innocent Still’s murmur, otherwise healthy
B. Completely repaired VSD with no residual defect, >1 year post-repair
C. Repaired tetralogy with residual VSD jet across a patch
D. Prior Kawasaki disease without coronary aneurysm
E. Functional (physiologic) tricuspid regurgitation

Answer and Remediation

A — Review: Innocent murmurs are not an indication for prophylaxis.
B — Review: Fully repaired CHD without residual defect beyond 6 months does not require prophylaxis.
C — Correct response!: Residual defects adjacent to prosthetic material warrant prophylaxis for dental procedures (AHA/ADA 2021).
D — Review: Kawasaki disease without residual coronary involvement is not an indication.
E — Review: Functional regurgitation alone is not an indication.

Mini Case Discussion Prompt

Compare the likelihood and microbiology of infective endocarditis in: (1) a 9-year-old with native bicuspid aortic valve and recent dental work; (2) a 2-year-old with a tunneled central line; and (3) an 8-month-old 4 weeks post-VSD patch with a residual shunt. How do risk contexts shift the most probable pathogens and urgency of echocardiography/blood culture strategies?

Mini-FAQ

Do boards expect classic peripheral stigmata (Osler nodes, Janeway lesions) in pediatric IE vignettes? Rarely; ABFM exams more often cue with fever + CHD risk factors and a murmur rather than peripheral signs.
Which organisms should I think of first in pediatric IE? Viridans group streptococci and Staphylococcus aureus; choose based on exposure (oral/dental vs. healthcare/line).
How does timing after CHD repair affect risk? Highest within months of surgery, especially with residual defects or prosthetic material; this is a high-yield test clue (AHA/AAP 2015).
Is CHF the most common presentation? No—fever is. CHF is a complication and less common at initial presentation.

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