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.
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)
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.
| 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. |
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.
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.
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 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 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?
Which child requires antibiotic prophylaxis for a dental extraction per current recommendations?
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?
Find this and other Family Medicine exam prep questions in Med-Challenger Family Medicine Review with CME
Try for free and save. Ace your exams and meet your CME/MOC requirements for just $35 a month!
No matter your program, no matter the size, Med-Challenger for Groups and Institutions can better prepare your program or group, fulfill industry requirements, and increase test scores.