Amniotic band syndrome
| Amniotic band syndrome | |
|---|---|
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| A baby's hand affected by amniotic band syndrome | |
| Classification and external resources | |
| Specialty | pediatrics |
| ICD-10 | P02.8 |
| ICD-9-CM | 762.8 |
| OMIM | 217100 |
| DiseasesDB | 32457 |
| MedlinePlus | 001579 |
| eMedicine | orthoped/561 |
| MeSH | D000652 |
Amniotic band constriction (also known as "amniotic band syndrome", "ADAM complex", "Amniotic band sequence", "Congenital constriction bands" and "Pseudoainhum") is a congenital disorder caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands while in utero.
The constriction of appendages by amniotic bands may result in:
A strong relationship between ABS and clubfoot (also called "talipes") exists. A 31.5% of associated clubfoot deformity and ABS can be correlated with 20% occurring bilaterally. Other abnormalities found with ABS include: clubhands, cleft lip, and/or cleft palate, and hemangioma.
Decreased fetal movement could be a sign of a serious problem which may include ABS. It is rare but possible for the membrane to become wrapped around the placenta or the neck of the baby in the womb causing strangulation and death.
To explain the cause of ABS, there are two main theories.
The amniotic band theory is that ABS occurs due to a partial rupture of the amniotic sac. This rupture involves only the amnion; the chorion remains intact. Fibrous bands of the ruptured amnion float in the amniotic fluid and can encircle and trap some part of the fetus. Later, as the fetus grows but the bands do not, the bands become constricting. This constriction reduces blood circulation, hence causes congenital abnormalities. In some cases a complete "natural" amputation of a digit(s) or limb may occur before birth or the digit(s) or limbs may be necrotic (dead) and require surgical amputation following birth.
The vascular disruption theory: Because the constricting mechanism of the amniotic band theory does not explain the high incidence of cleft palate and other forms of cleft defects occurring together with ABS, this co-occurrence suggests an "intrinsic" defect of the blood circulation.
Amniotic band syndrome is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus.
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Wikipedia