Craniopagus parasiticus

Craniopagus parasiticus Definition

Craniopagus Parasiticus is a rare type of birth defect that occurs in about 4 to 6 children out of 10,000,000 births. It is found to be more prevalent in male children.

Craniopagus parasiticus Symptoms

In this condition, the skulls of conjoined twins get fused together although they have separate bodies. In this condition, a parasitic twin head with an undeveloped body is attached to the head of a developed twin. Most individuals affected by this disorder are stillborn or die soon after or during surgery.

Craniopagus Parasiticus Causes

An underdeveloped twin with this condition is known as a parasitic twin. Parasitic twins develop in the uterus when the twins are starting to grow from the embryo. However, the embryo fails to split totally. When this condition arises, one embryo tries to dominate the development of the other.

Picture of Craniopagus Parasiticus

Picture 1 – Craniopagus parasiticus

The biological explanation for the occurrence of this condition is that two fetuses from a single zygote are unable to separate at the head region during the second week of gestation. The two embryos are believed to fuse together at the fourth week of gestation near the anterior open neuropore. Another explanation for the occurrence of this condition is the joining of the somatic and placental vascular system of the twin and degeneration of the umbilical cord of that connects the parasitic twin. This means that this condition develops due to reduced blood supply to one of the twins.

Craniopagus Parasiticus Diagnosis

The diagnosis of this condition is done by tests like:

Image of Craniopagus Parasiticus

Picture 2 – Craniopagus Parasiticus Image

  • Computed tomography
  • Magnetic resonance angiography
  • Computed tomographic angiography
  • Magnetic resonance imaging

Craniopagus Parasiticus Treatment

Surgery, which attempts to remove a parasitic twin, is the only treatment option for this condition. Operative techniques, however, are dangerous and have been found to be successful only in a few cases. The difficulty with surgical interventions is that the arterial supplies of the head get entwined. This is not an easy task to control the bleeding. Medical experts suggest that blocking the arterial supply of the parasitic twin might improve the situation.

Craniopagus Parasiticus Prognosis

The prognosis of the disorder is generally poor. About 80 isolated cases of this disease have been reported. Survival has been reported in only three out of these cases.


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