🫀 Chapter 493.1: Aneurysms
Nelson's Textbook of Pediatrics 22e | Kawasaki disease · Coronary aneurysms · MIS-C · Marfan syndrome · Loeys-Dietz syndrome · ACTA2 · Ehlers-Danlos · GACI · Aortic root dilation · Anticoagulation · Beta-blockers · Transition
📚 Reference: www.paeds.online — Paediatric Resource Hub
📌 Kawasaki Disease – Coronary AneurysmsLeading cause of acquired heart disease in children. Coronary artery aneurysms (z-score >2.5) in 25% if untreated, 5% if treated with IVIG. Giant aneurysms (>8 mm) risk thrombosis, MI. Manage with aspirin, anticoagulation (warfarin), beta-blockers.
📌 MIS-C – Coronary AneurysmsCOVID-19-associated multisystem inflammatory syndrome in children. Coronary dilation/aneurysms (10-20%). Treatment: IVIG, corticosteroids. Usually regress.
📌 Marfan Syndrome – Aortic AneurysmFBN1 mutation (fibrillin-1). Aortic root dilation, risk of dissection. Beta-blockers (propranolol, atenolol), losartan (ARB). Prophylactic root replacement when diameter >50 mm (adults) or >95th percentile for age.
📌 Loeys-Dietz SyndromeTGFBR1, TGFBR2 mutations. Arterial tortuosity, aneurysms (aortic, branch vessels), hypertelorism, bifid uvula. Aggressive aortic root replacement (>40-45 mm).
📌 ACTA2 Multisystem Smooth Muscle Dysfunction SyndromeACTA2 mutation. Congenital mydriasis, patent ductus arteriosus, aortic aneurysms, moyamoya disease, pulmonary hypertension.
📌 Generalized Arterial Calcification of Infancy (GACI)ENPP1 or ABCC6 mutations. Vascular calcification, stenosis, heart failure. Bisphosphonates. May present with hydrops fetalis.
📌 Ehlers-Danlos Syndrome (Vascular type, type IV)COL3A1 mutation. Arterial rupture, bowel rupture. Pregnancy high-risk. Avoid elective surgery.
📌 Surveillance for Coronary Aneurysms – KDEchocardiogram at 2 weeks, 6 weeks, 6 months, 1 year, then annually if persistent. Giant aneurysms: life-long surveillance.
📌 Surveillance for Aortic Aneurysm – MarfanAnnual echocardiogram to measure aortic root at sinuses of Valsalva. MRI/CT if echo suboptimal. Beta-blockers/losartan.
📌 Pregnancy in Marfan/Loeys-DietzHigh risk of aortic dissection (especially if aortic root >40 mm). Beta-blockers, C-section. Pre-conception counseling.
🔍 Step 1: Kawasaki disease – coronary aneurysm
Fever >5 days, rash, conjunctivitis, oral changes, extremity changes, cervical lymphadenopathy. Echocardiogram: coronary artery dilation/aneurysm.
📈 Step 2: Connective tissue disorders (Marfan, Loeys-Dietz)
Tall stature, arachnodactyly, pectus deformity, scoliosis, lens dislocation (Marfan), hypertelorism/bifid uvula (Loeys-Dietz). Aortic root dilation on echo.
🩺 Step 3: Vascular Ehlers-Danlos
Thin translucent skin, easy bruising, arterial rupture. Family history of sudden death. COL3A1 mutation.
🔄 Step 4: ACTA2 multisystem smooth muscle dysfunction
Congenital mydriasis (fixed dilated pupils), PDA, aortic aneurysms, moyamoya, pulmonary hypertension.
🚨 Step 5: Generalized arterial calcification of infancy (GACI)
Hydrops fetalis, heart failure, hypertension, vascular calcification on X-ray. ENPP1 mutation.
1️⃣ Kawasaki disease – Coronary aneurysms
▪ IVIG 2 g/kg + aspirin 30-50 mg/kg/day until afebrile, then 3-5 mg/kg/day.
▪ Giant aneurysms (>8 mm): warfarin (INR 2-2.5) + low-dose aspirin. Avoid intense exercise.
▪ Surveillance echo at 2 weeks, 6 weeks, 6 months, 1 year, then annually.
2️⃣ MIS-C – Coronary dilation
▪ IVIG + corticosteroids. Usually regresses.
▪ Aspirin until normalization.
3️⃣ Marfan syndrome – Aortic root aneurysm
▪ Beta-blockers (atenolol, propranolol) first-line. Losartan (ARB) also effective.
▪ Restrict competitive sports, contact sports.
▪ Prophylactic aortic root replacement when diameter >50 mm (adult) or >95th percentile with rapid growth >5 mm/year.
4️⃣ Loeys-Dietz syndrome
▪ Aggressive beta-blocker/losartan therapy. Earlier surgery (40-45 mm).
▪ Surveillance imaging every 6-12 months.
5️⃣ Generalized arterial calcification of infancy (GACI)
▪ Bisphosphonates (pamidronate, etidronate).
▪ Treat heart failure (diuretics, inotropes).
▪ Avoid calcium supplementation.
6️⃣ Vascular Ehlers-Danlos (COL3A1)
▪ Avoid contact sports, elective surgery.
▪ Antihypertensives (beta-blockers).
▪ Emergency: control bleeding, surgical repair.
7️⃣ Transition & pregnancy
▪ Marfan, Loeys-Dietz: pregnancy high-risk (aortic dissection). Pre-conception counseling, beta-blockers, C-section.
▪ Lifelong surveillance of aneurysms (imaging every 1-2 years).
❓ Reflex prompt 1: A 4-year-old with Kawasaki disease, echocardiogram shows giant coronary aneurysm (8 mm). Next step?
✅ Answer: Warfarin + low-dose aspirin. Surveillance echo. Avoid vigorous exercise.
❓ Reflex prompt 2: A 10-year-old with Marfan syndrome, aortic root z-score +4.5. First-line medication?
✅ Answer: Beta-blocker (atenolol, propranolol) or losartan.
❓ Reflex prompt 3: A 16-year-old with Loeys-Dietz syndrome, aortic root 42 mm, rapid growth. Next step?
✅ Answer: Prophylactic aortic root replacement (surgery).
❓ Reflex prompt 4: A newborn with ACTA2 multisystem smooth muscle dysfunction syndrome. Which finding is characteristic?
✅ Answer: Congenital mydriasis (fixed dilated pupils).
❓ Reflex prompt 5: A 3-month-old with generalized arterial calcification of infancy (GACI). Treatment:?
✅ Answer: Bisphosphonates (pamidronate, etidronate).
❓ Reflex prompt 6: A 14-year-old with Ehlers-Danlos syndrome (vascular type). Which gene mutation?
✅ Answer: COL3A1.
📌 Aneurysms – Core Concepts (Nelson 22e, Chapter 493.1)

1. Kawasaki disease: Most common cause of acquired coronary artery aneurysms. Giant aneurysms (>8 mm) risk thrombosis, myocardial infarction. Treatment: IVIG, aspirin. Warfarin for giant aneurysms.
2. MIS-C (COVID-19): Coronary dilation/aneurysms (10-20%). IVIG, corticosteroids. Usually regresses.
3. Marfan syndrome (FBN1): Aortic root dilation, risk of dissection. Beta-blockers, losartan. Prophylactic root replacement when diameter >50 mm (adult) or >95th percentile.
4. Loeys-Dietz syndrome (TGFBR1, TGFBR2): Arterial tortuosity, aggressive aneurysms, hypertelorism, bifid uvula. Earlier surgery (40-45 mm).
5. ACTA2 multisystem smooth muscle dysfunction syndrome: Congenital mydriasis, PDA, aortic aneurysms, moyamoya, pulmonary hypertension.
6. Generalized arterial calcification of infancy (GACI – ENPP1, ABCC6): Vascular calcification, heart failure. Bisphosphonates.
7. Ehlers-Danlos syndrome (vascular type, COL3A1): Arterial rupture. Pregnancy high-risk.
8. Surveillance: KD: echocardiogram at 2 weeks, 6 weeks, 6 months, 1 year. Marfan: annual echo. Loeys-Dietz: every 6-12 months.
9. Pregnancy: High-risk in Marfan/Loeys-Dietz (aortic dissection). Beta-blockers, C-section.
💡 Clinical pearls:
➤ Kawasaki disease: echocardiogram at diagnosis and 2 weeks for coronary assessment.
➤ Marfan: annual echocardiogram to monitor aortic root.
➤ Giant coronary aneurysms: warfarin + aspirin.
➤ Loeys-Dietz: earlier surgical intervention than Marfan.
➤ ACTA2: fixed dilated pupils (mydriasis) is a clue.