Amniotic band syndrome

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Amniotic band syndrome (ABS) comprises of a wide spectrum of abnormalities which result ~~from~~ from entrapment of various fetal parts from a disrupted amnion. Due to the randomness of entrapment, each affected individual has the potential to form a very unique deficit.

Epidemiology

The phenomenon is estimated to occur in ~1:1200-1300 live births ^1,8.

Pathology

The exact pathogenesis is not well known although several theories have been proposed.

Exogenous theory

An early disruption of the amnion ~~allows~~ allows the embryo or fetus to enter the chorionic cavity and contact the chorionic side of the amnion leading to fibrous bands, which entrap the fetal body components.

Endogenous theory

Occurs as a result of vascular compromise with mesoblastic strings not being a causal agent ⁴.

Associations

The vast majority of cases have a sporadic occurrence ⁸. In ~~rare~~ rare situations, it may be associated with:

Radiographic features

There is a massive spectrum of abnormalities depending on what part gets entrapped and at what ~~point in~~ time of gestation. Features are often asymmetrical. Observable features according to position include:

Head/face entrapment

acrania
anencephaly
facial clefts
nasal deformities
asymmetric microphthalmos

Truncal entrapment

Extremity entrapment

Limb defects tend to be the commonest ⁷

variable levels of limb amputation
variable levels of limb constriction +/- atrophy
lymphoedema distal to the level of the band constriction
pseudosyndactyly
club feet
phocomelia ²

In addition to these defects, actual background amniotic bands may also be detected on ultrasound.

Treatment and prognosis

The prognosis is extremely variable dependent on the part that gets entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment to in-utero death if there is ~~anencephaly~~ anencephaly from head entrapment. There is no recognised recurrence risk for future pregnancies.

Differential diagnosis

The differential is extremely variable dependent on the type of deficit and is best left for individual features.

-<p><strong>Amniotic band syndrome (ABS)</strong> comprises of a wide spectrum of abnormalities which result from entrapment of various fetal parts from a disrupted <a href="/articles/amnion">amnion</a>. Due to the randomness of entrapment, each affected individual has the potential to form a very unique deficit. </p><h4>Epidemiology</h4><p>The phenomenon is estimated to occur in ~1:1200-1300 live births <sup>1,8</sup>.</p><h4>Pathology</h4><p>The exact pathogenesis is not well known although several theories have been proposed. </p><h6>Exogenous theory</h6><p>An early disruption of the amnion allows the embryo or fetus to enter the chorionic cavity and contact the chorionic side of the amnion leading to fibrous bands, which entrap the fetal body components.</p><h6>Endogenous theory </h6><p>Occurs as a result of vascular compromise with mesoblastic strings not being a causal agent <sup>4</sup>.</p><h5>Associations</h5><p>The vast majority of cases have a sporadic occurrence <sup>8</sup>. In rare situations, it may be associated with:</p><ul>
~~-<li><a href="/articles/ehlers-danlos-syndrome-2">Ehlers-Danlos syndrome </a></li>~~
+<p><strong>Amniotic band syndrome (ABS)</strong> comprises of a wide spectrum of abnormalities which result from entrapment of various fetal parts from a disrupted <a href="/articles/amnion">amnion</a>. Due to the randomness of entrapment, each affected individual has the potential to form a very unique deficit. </p><h4>Epidemiology</h4><p>The phenomenon is estimated to occur in ~1:1200-1300 live births <sup>1,8</sup>.</p><h4>Pathology</h4><p>The exact pathogenesis is not well known although several theories have been proposed. </p><h6>Exogenous theory</h6><p>An early disruption of the amnion allows the embryo or fetus to enter the chorionic cavity and contact the chorionic side of the amnion leading to fibrous bands, which entrap the fetal body components.</p><h6>Endogenous theory </h6><p>Occurs as a result of vascular compromise with mesoblastic strings not being a causal agent <sup>4</sup>.</p><h5>Associations</h5><p>The vast majority of cases have a sporadic occurrence <sup>8</sup>. In rare situations, it may be associated with:</p><ul>
+<li><a href="/articles/ehlers-danlos-syndrome-2">Ehlers-Danlos syndrome </a></li>
-</ul><h4>Radiographic features</h4><p>There is a massive spectrum of abnormalities depending on what part gets entrapped and at what point in time of gestation. Features are often asymmetrical. Observable features according to position include:</p><h6>Head/face entrapment</h6><ul>
+</ul><h4>Radiographic features</h4><p>There is a massive spectrum of abnormalities depending on what part gets entrapped and at what time of gestation. Features are often asymmetrical. Observable features according to position include:</p><h6>Head/face entrapment</h6><ul>
~~-<li><a href="/articles/facial-clefts">facial clefts </a></li>~~
+<li><a href="/articles/facial-clefts">facial clefts </a></li>
+<li>nasal deformities</li>
+<li>asymmetric <a title="Microphthalmos" href="/articles/microphthalmia">microphthalmos</a>
+</li>
+<li>ambiguous genitalia</li>
+<li><a title="Imperforate anus" href="/articles/anal-atresia">imperforate anus</a></li>
~~-<li><a href="/articles/pseudosyndactylity">pseudosyndactylity</a></li>~~
+<li><a title="Pseudosyndactyly" href="/articles/pseudosyndactyly">pseudosyndactyly</a></li>
+<li><a title="Club feet" href="/articles/congenital-talipes-equinovarus">club feet</a></li>
-</ul><p>In addition to these defects, actual background <a href="/articles/amniotic-bands">amniotic bands</a> may also be detected on ultrasound.</p><h4>Treatment and prognosis</h4><p>The prognosis is extremely variable dependent on the part that gets entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment to in-utero death if there is anencephaly from head entrapment. There is no recognised recurrence risk for future pregnancies.</p><h4>Differential diagnosis</h4><p>The differential is extremely variable dependent on the type of deficit and is best left for individual features.</p><h4>See also</h4><ul><li><a href="/articles/limb-body-wall-complex">limb body wall complex</a></li></ul>
+</ul><p>In addition to these defects, actual background <a href="/articles/amniotic-bands">amniotic bands</a> may also be detected on ultrasound.</p><h4>Treatment and prognosis</h4><p>The prognosis is extremely variable dependent on the part that gets entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment to in-utero death if there is anencephaly from head entrapment. There is no recognised recurrence risk for future pregnancies.</p><h4>Differential diagnosis</h4><p>The differential is extremely variable dependent on the type of deficit and is best left for individual features.</p><h4>See also</h4><ul><li><a href="/articles/limb-body-wall-complex">limb body wall complex</a></li></ul>

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