Tag Archives: marfan syndrome

Marfan Syndrome

Posted on March 7, 2011 by admin

Marfan Syndrome

- inherited defect in extracellular glycoprotein, fibrillin

- mutations to FBN1 or FBN2 (FBN1 is on 15q21)

Marfan syndrome pathology

- skeletal system: long tapering fingers and toes, frontal bossing, kyphosis, scoliosis, ectopia lentis (bilateral subluxation or dislocation), pectus excavatum/pigeon chest

- CVS: MVP, cystic medionecrosis of the aorta-this can lead to:

-intramural hematoma – which can lead to aortic dissection-can lead to death

-dilation of aortic root (aneurysm) which leads to aortic incompentence → CHF

Marfan Syndrome Summary:

- autosomal dominant

- mutations in fibrillin 1/2,  FBN

- long fingers, toes, legs

- pectus excavatum

- ectopia lentis

- cystic medionecrosis

- aortic insufficiency

- aortic dissection

- mitral valve prolapse MVP

- congestive heart failure CHF

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Mitral Valve Prolapse

Posted on January 16, 2011 by admin

Mitral valve prolapse

Clinical features

•    Often asymptomatic; incidental mid-systolic click often heard on routine physical exam

•    In cases with mitral regurgitation, late systolic, or holosystolic murmur may be heard

•    May have angina, dyspnea, fatigue

•    Some may manifest psychiatric symptoms (depression, anxiety disorders, personality disorders)

Gross features

•    Intercordal ballooning (“hooding”) of mitral valve leaflets (or portions of the leaflets)

•    Leaflets may be enlarged, thickened, redundant, and rubbery

•    Tendinous cords are thinned, elongated, sometimes ruptured; annular dilatation is characteristic

Secondary changes include:

o    Fibrous thickening of valve leaflets

o    Linear fibrous thickening of left ventricular endocardium

o    Thickening of mural endocardium of left ventricle or atrium

o    Thrombi on atrial surfaces of leaflets

o    Focal calcifications at base of posterior mitral leaflet

Histological features

•    Attenuation of the fibrosa layer with marked thickening of the spongiosa layer with deposition of mucoid material

•    Attenuation of the collagenous structure of the cords

Clinical complications

•    Infective endocarditis

•    Mitral valve insufficiency

•    Stroke, systemic infarcts

•    Arrhythmias (ventricular and atrial)

Mitral Valve Pathogenesis

•    Unknown, but thought to be due to underlying developmental defect of connective tissue (most likely systemic)

•    Common feature in Marfan syndrome (mutation in fibrillin-1) and other hereditary connective tissue disorders

•    Some individuals have signs of systemic connective tissue abnormalities evidenced by scoliosis, straight back and high-arched palate

•    Thought that defects in structural proteins predispose tissues rich in microfibrils and elastin (such as valves) to damage by long-standing hemodynamic stress

•    Alternatively, primary hemodynamic, cellular or metabolic abnormality may induce prominent destruction and remodelling of connective tissue

Reference:

Robbins & Cotran Pathologic Basis of Disease, Seventh Edition
by: Vinay Kumar, Nelso Fausto, Abul Abbas

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Berry Aneurysm

Posted on June 29, 2010 by admin

Berry  Aneurysm

Most common locations of Berry Aneurysms:

·         Anterior cerebral artery (anterior communicating artery)

·         Middle cerebral artery

·         Internal carotid artery

Associated systemic conditions for Berry Aneurysms:

·         ADPCKD

·         Ehlers-Danlos syndrome (type IV)

·         Neurofibromatosis type 1

·         Marfan syndrome

·         Coarctation of aorta

·         Fibromuscular dysplasia of extracranial arteries

Predisposing factors for Berry Aneurysms:

-   Cigarette smoking and hypertension are

Berry Aneurysm Gross Features

Unruptured aneurysms are a thin-walled arterial outpouchings at branch points of the circle of Willis or a major vessel just beyond. Measure 2-3 mm and are shiny, bright red surface with thin, translucent wall. Atheromatous plaques, thrombosis, or calcification may be found in wall or lumen of aneurysm. Brownish discolouration of brain/meninges indicates previous hemorrhage. Rupture occurs at apex of sac with extravasation of blood to subarachnoid space, substance of brain, or both.

Histological Features of Berry Aneurysms:

Arterial wall adjacent to aneurysm shows intimal thickening and attenuation of media as it approaches the neck of the aneurysm. At the neck of the aneurysm the muscular wall and intimal elastic lamina stop short and are absent from the aneurysmal wall itself. The sac is made up of thickened, hyalinised intima. The adventitia covering the sac is continuous with that of the parent artery

References:

Robbins Basic Pathology 7th ed, edited by Vinay Kumar, Ramzi S. Cotran, and Stanley J. Robbins, 873 pp, Philadelphia, Pa, Sounders, 2003.

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