Anencephaly

ANENCEPHALY (from Greek a- negative particle and enkephalos-brain), congenital absence of the brain; observed simultaneously with defects in skull development (see Acrania), and sometimes of the spine (craniorachischisis) and spinal cord (amyelia); the peripheral nervous system may be normally developed in this condition. Of particular interest is the hypoplasia or agenesis of the adrenal glands in A. Based on the similarity of hypoplastic adrenal glands in anencephaly to normally involuting adrenal glands of infants (in terms of low weight of the adrenal glands, content of cholesterol esters, etc.), it is suggested that there is premature involution of the adrenal glands in A. The pituitary gland is never absent in A, but is represented only by the anterior lobe. The thyroid gland, like the pineal gland, may be absent. The thyroid gland and sex glands show no particular deviations. Fetuses with A are nonviable; as an exception, they may live for several days, with cases of crying in newborns, as well as sucking and swallowing movements observed in the presence of only the lower part of the medulla oblongata; at the same time, increased reflexes were noted.