Dilated Aorta
Alexander J. Towbin, MD
DIFFERENTIAL DIAGNOSIS
Common
Marfan Syndrome
Turner Syndrome
Aortic Stenosis
Less Common
Takayasu Arteritis
Neurofibromatosis Type 1 (NF1)
Ehlers-Danlos Syndrome
Rare but Important
Trauma
Loeys-Dietz Syndrome
Tuberous Sclerosis
Mycotic Aneurysm
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Dilated aorta often caused by aortic aneurysm
Causes of aortic aneurysm: Connective tissue disorders, vasculitis, trauma, or infection
Helpful Clues for Common Diagnoses
Marfan Syndrome
Autosomal dominant connective tissue disorder
Characteristic features: Dural ectasia, bullae and pneumothorax, arachnodactyly, ectopia lentis, and retinal detachment
Affects multiple systems, including cardiovascular, musculoskeletal, central nervous, pulmonary, and ocular
Cardiovascular manifestations: Aortic annulus ectasia, aortic aneurysm, aortic valve insufficiency, aortic dissection
Death caused by aortic dissection, congestive heart failure, or valvular disease in > 90%
Dilated aortic root seen in 60-80% of adults and leads to aortic insufficiency
Prophylactic surgery: When diameter of sinus of Valsalva is > 5 cm
Musculoskeletal deformities include pectus excavatum, pectus carinatum, or scoliosis
Turner Syndrome
Monosomy of X chromosome (45 XO)
Characteristic features include short stature, webbed neck, lymphedema, short 4th metacarpals, and gonadal insufficiency
Lymphatic malformation on prenatal ultrasound
Congenital heart defects (CHD): Bicuspid aortic valve, aortic coarctation, partial anomalous pulmonary venous return
Generalized dilation of aorta can occur
Potential complication: Aortic dissection
Risks for dissection: Hypertension, bicuspid aortic valve, and coarctation
Aortic Stenosis
Can be valvular, subaortic, or supravalvular
Valvular aortic stenosis is most common
Accounts for 3-6% of CHD
4x more common in males
˜ 20% have associated cardiac anomaly
Chest x-ray (CXR) can show cardiomegaly, vascular congestion, or poststenotic dilation of ascending aorta
Subaortic stenosis can be discrete or diffuse
Discrete form is caused by thin fibromuscular membrane
In diffuse form, stenosis extends along ventricular septum
Supravalvular is least common
Narrowing of aortic root at or above sinotubular ridge
Association: Pulmonary artery stenosis
Helpful Clues for Less Common Diagnoses
Takayasu Arteritis
Chronic vasculitis of unknown etiology
Large vessel vasculitis affects aorta, its main branches, and pulmonary arteries
3rd most common vasculitis of childhood
Most commonly presents between 10-20 years of age
8.5x more common in females
Associated with tuberculosis infection
Pulseless arteritis is characteristic of chronic disease
Often leads to hypertension, congestive heart failure, or aortic regurgitation
CXR aorta: Undulating border, segmental calcification
Aortic aneurysms can occur
CXR pulmonary arteries: Oligemia
CT or MR shows thickened arterial wall with enhancement
Neurofibromatosis Type 1 (NF1)
Autosomal dominant disorder
Affects 1:3,000 individuals
Characteristic features: Café au lait macules, benign neurofibromas, plexiform neurofibromas, and iris hamartomas
NF1 vasculopathy is uncommon component of NF1
Affects medium and large vessels
Aneurysms, stenoses, and arteriovenous malformations occur
Renal artery is most commonly affected
Aortic aneurysms and stenoses are common
Ehlers-Danlos Syndrome
Ehlers-Danlos type 4 is vascular
Features: Acrogeria; thin, translucent skin; ecchymoses and hematoma; and arterial, digestive, and obstetric ruptures
Arterial complications are leading cause of death
Complications most common in medium and large vessels
Complications include arterial rupture, aneurysm, and dissection
Complications uncommon in childhood
Association: Peripheral pulmonary stenosis
Helpful Clues for Rare Diagnoses
Trauma
Most common cause of death in children
Traumatic aortic injuries are uncommon
Iatrogenic trauma is most common cause of aortic injury in children
More common in teenage years
Associated traumatic injuries are common
Loeys-Dietz Syndrome
Syndrome with craniofacial and vascular manifestations
Vascular features include arterial aneurysms and tortuosity
Aneurysms → rupture or dissection
Features of Marfan syndrome
2 types distinguished by phenotype
Type 1: Hypertelorism, broad or bifid uvula, cleft palate, craniosynostosis
Type 2: No cleft palate, craniosynostosis, or hypertelorism
Aortic root aneurysm are common
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