Neural tube defect
A major birth defect caused by abnormal development of the neural tube, the structure that is present during embryonic life that gives rise to the central nervous system. Abbreviated NTD. NTDs are among the most common birth defects resulting in infant death and serious disability. There are a number of different types of NTDs, including anencephaly, spina bifida, and encephalocele. In anencephaly there is absence of the cranial vault (the skull) and absence of most or all of the cerebral hemispheres of the brain. Encephalocele is a hernia of part of the brain, and the membranes covering it (meninges), through a skull defect. Spina bifida is an opening in the vertebral column encasing the spinal cord. Through this opening, the spinal cord and the meninges may herniate to create a meningomyelocele. All pregnancies are at risk for NTDs. Factors that increase the risk include a prior NTD in the family and type 1 diabetes in the mother. More than half of NTDs can be prevented if women consume supplements that contain folic acid before and during the early weeks of pregnancy in addition to getting folate in their diets. Because the risk for NTDs is not totally eliminated by folic acid use, routine prenatal screening for NTDs is still advisable.
Read Also:
- Neuralgia
Pain along the course of a nerve.
- Neuralgia, ciliary
Characterized by the absence of sustained periods of remission, chronic cluster headache may start with no past history of cluster headaches, or it may emerge several years after the patient has experienced an episodic pattern of cluster headaches. The episodic and acute forms of cluster headache may transform into one another, so it seems most […]
- Neuralgia, facial
Severe pain that usually occurs in bursts along the path of the trigeminal nerve, the chief sensory nerve of the face.
- Neuralgia, migrainous
Characterized by the absence of sustained periods of remission, chronic cluster headache may start with no past history of cluster headaches, or it may emerge several years after the patient has experienced an episodic pattern of cluster headaches. The episodic and acute forms of cluster headache may transform into one another, so it seems most […]
- Neuralgia, postherpetic
The most common complication of shingles, persistence of the pain associated with shingles beyond 1 month, even after the rash is gone. The pain can be severe and debilitating, and it occurs primarily in persons over age 50. The pain of postherpetic neuralgia can be reduced by certain medications including tricyclic antidepressant medications and some […]