Amniotic band syndrome
Updates to Article Attributes
Amniotic band syndrome (ABS) comprises a wide spectrum of abnormalities, all of which result from entrapment of various fetal body parts in a disrupted amnion. Due to the randomness of entrapment, each affected individual has the potential to form a unique deficit.
Epidemiology
The phenomenon is estimated to occur in ~1:1200-1300 live births 1,8.
Associations
The vast majority of cases have a sporadic occurrence 8. In rare situations, it may be associated with:
Pathology
The exact pathogenesis is not well known, although several etiologiesaetiologies have been proposed.
Exogenous theory
Proposed by Torpin in 1965 10, it is still the most widely accepted theory.A disruption in the amnion allows the embryo or fetus to enter the chorionic cavity, where body parts become entangled in fibrous mesodermic strands emanating from the chorionic side of the amnion. If occurring early in gestation, this can potentially cause multiple malformations.
Endogenous theory
Proposes that a vascular insult during early embryogenesis is responsible for amniotic band syndrome 4.
Associations
The vast majority of cases have a sporadic occurrence 8. In rare situations, it may be associated with:
Radiographic features
There is a massive spectrum of abnormalities, depending on which part becomes entrapped and at what stage of gestation. Features are often asymmetrical. Observable features according to location include:
Head/face entrapment
nasal deformities
asymmetric microphthalmos
Truncal entrapment
Extremity entrapment
Limb defects tend to be the commonest 7,11:
variable levels of limb amputation
variable levels of limb constriction, with possible distal atrophy
lymphedemalymphoedema distal to the level of the band constriction
In addition to these defects, actual background amniotic bands may also be detected on antenatal ultrasound.
Treatment and prognosis
The prognosis is extremely variable, depending on the part that becomes entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment as a surgical repair, to in-utero demise in the case of anencephaly from head entrapment 11. There is no recognised risk of recurrence for future pregnancies.
Differential diagnosis
The differential is extremely variable, depending on the type of deficit.
See also
-<p><strong>Amniotic band syndrome (ABS)</strong> comprises a wide spectrum of abnormalities, all of which result from entrapment of various fetal body parts in a disrupted <a href="/articles/amnion">amnion</a>. Due to the randomness of entrapment, each affected individual has the potential to form a 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 etiologies have been proposed.</p><h6>Exogenous theory</h6><p>Proposed by Torpin in 1965 <sup>10</sup>, it is still the most widely accepted theory.<br>A disruption in the amnion allows the embryo or fetus to enter the chorionic cavity, where body parts become entangled in fibrous mesodermic strands emanating from the chorionic side of the amnion. If occurring early in gestation, this can potentially cause multiple malformations.</p><h6>Endogenous theory</h6><p>Proposes that a vascular insult during early embryogenesis is responsible for amniotic band syndrome <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>-<li><a href="/articles/epidermolysis-bullosa">epidermolysis bullosa</a></li>-</ul><h4>Radiographic features</h4><p>There is a massive spectrum of abnormalities, depending on which part becomes entrapped and at what stage of gestation. Features are often asymmetrical. Observable features according to location include:</p><h6>Head/face entrapment</h6><ul>-<li><a href="/articles/acrania">acrania</a></li>-<li><a href="/articles/anencephaly">anencephaly</a></li>-<li><a href="/articles/facial-clefts">facial clefts </a></li>-<li>nasal deformities</li>-<li>asymmetric <a href="/articles/microphthalmia">microphthalmos</a>-</li>- +<p><strong>Amniotic band syndrome (ABS)</strong> comprises a wide spectrum of abnormalities, all of which result from entrapment of various fetal body parts in a disrupted <a href="/articles/amnion">amnion</a>. Due to the randomness of entrapment, each affected individual has the potential to form a unique deficit.</p><h4>Epidemiology</h4><p>The phenomenon is estimated to occur in ~1:1200-1300 live births <sup>1,8</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><p><a href="/articles/ehlers-danlos-syndrome-2">Ehlers-Danlos syndrome</a></p></li>
- +<li><p><a href="/articles/epidermolysis-bullosa">epidermolysis bullosa</a></p></li>
- +</ul><h4>Pathology</h4><p>The exact pathogenesis is not well known, although several aetiologies have been proposed.</p><h6>Exogenous theory</h6><p>Proposed by Torpin in 1965 <sup>10</sup>, it is still the most widely accepted theory.<br>A disruption in the amnion allows the embryo or fetus to enter the chorionic cavity, where body parts become entangled in fibrous mesodermic strands emanating from the chorionic side of the amnion. If occurring early in gestation, this can potentially cause multiple malformations.</p><h6>Endogenous theory</h6><p>Proposes that a vascular insult during early embryogenesis is responsible for amniotic band syndrome <sup>4</sup>.</p><h4>Radiographic features</h4><p>There is a massive spectrum of abnormalities, depending on which part becomes entrapped and at what stage of gestation. Features are often asymmetrical. Observable features according to location include:</p><h6>Head/face entrapment</h6><ul>
- +<li><p><a href="/articles/acrania">acrania</a></p></li>
- +<li><p><a href="/articles/anencephaly">anencephaly</a></p></li>
- +<li><p><a href="/articles/facial-clefts">facial clefts</a></p></li>
- +<li><p>nasal deformities</p></li>
- +<li><p>asymmetric <a href="/articles/microphthalmia">microphthalmos</a></p></li>
-<li><a href="/articles/fetal-anterior-abdominal-wall-defects">abdominal wall defects</a></li>-<li><a href="/articles/rib-clefting">rib clefting</a></li>-<li><a href="/articles/congenital-scoliosis">congenital scoliosis</a></li>-<li>ambiguous genitalia</li>-<li><a href="/articles/anal-atresia">imperforate anus</a></li>- +<li><p><a href="/articles/fetal-anterior-abdominal-wall-defects">abdominal wall defects</a></p></li>
- +<li><p><a href="/articles/rib-clefting">rib clefting</a></p></li>
- +<li><p><a href="/articles/congenital-scoliosis">congenital scoliosis</a></p></li>
- +<li><p>ambiguous genitalia</p></li>
- +<li><p><a href="/articles/anal-atresia-2">imperforate anus</a></p></li>
-<li>variable levels of <a href="/articles/congenital-limb-amputation">limb amputation</a>-</li>-<li>variable levels of <a href="/articles/limb-constriction">limb constriction</a>, with possible distal atrophy</li>-<li>-<a href="/articles/lymphoedema">lymphedema</a> distal to the level of the band constriction</li>-<li><a href="/articles/pseudosyndactyly">pseudosyndactyly</a></li>-<li><a href="/articles/congenital-talipes-equinovarus">clubfoot</a></li>-<li>-<a href="/articles/phocomelia">phocomelia</a> <sup>2</sup>-</li>-</ul><p>In addition to these defects, actual background <a href="/articles/amniotic-bands">amniotic bands</a> may also be detected on antenatal ultrasound.</p><h4>Treatment and prognosis</h4><p>The prognosis is extremely variable, depending on the part that becomes entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment as a surgical repair, to in-utero demise in the case of anencephaly from head entrapment <sup>11</sup>. There is no recognised risk of recurrence for future pregnancies.</p><h4>Differential diagnosis</h4><p>The differential is extremely variable, depending on the type of deficit.</p><h4>See also</h4><ul><li><a href="/articles/limb-body-wall-complex">limb body wall complex</a></li></ul>- +<li><p>variable levels of <a href="/articles/congenital-limb-amputation">limb amputation</a></p></li>
- +<li><p>variable levels of <a href="/articles/limb-constriction">limb constriction</a>, with possible distal atrophy</p></li>
- +<li><p><a href="/articles/lymphoedema">lymphoedema</a> distal to the level of the band constriction</p></li>
- +<li><p><a href="/articles/pseudosyndactyly">pseudosyndactyly</a></p></li>
- +<li><p><a href="/articles/congenital-talipes-equinovarus">clubfoot</a></p></li>
- +<li><p><a href="/articles/phocomelia">phocomelia</a> <sup>2</sup></p></li>
- +</ul><p>In addition to these defects, actual background <a href="/articles/amniotic-bands">amniotic bands</a> may also be detected on antenatal ultrasound.</p><h4>Treatment and prognosis</h4><p>The prognosis is extremely variable, depending on the part that becomes entrapped. This can range from normal life expectancy at one extreme in the case of a minor distal limb entrapment as a surgical repair, to in-utero demise in the case of anencephaly from head entrapment <sup>11</sup>. There is no recognised risk of recurrence for future pregnancies.</p><h4>Differential diagnosis</h4><p>The differential is extremely variable, depending on the type of deficit.</p><h4>See also</h4><ul><li><p><a href="/articles/limb-body-wall-complex">limb body wall complex</a></p></li></ul>
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