Neural Tube Defects (Part 1) - For Ob/GYN Test On 4/29/11

Taking folic acid supplements before and during early pregnancy may help reduce the occurrence of neural tube defects (NTD's). Folic acid is a B vitamin that is crucial for the development of the neural tube in the early stages of pregnancy. By ensuring an adequate intake of folic acid, the risk of NTD's such as spina bifida and anencephaly can be significantly reduced. While it cannot cure NTD's, folic acid supplementation is a preventive measure that can have a positive impact on reducing their occurrence.

Encephalocele, a rare neural tube defect, is a condition where the brain tissue protrudes through an opening in the skull. It appears as a sac-like structure filled with cerebrospinal fluid. On the other hand, a cystic hygroma is a fluid-filled sac that forms on the neck or head due to blockage in the lymphatic system. Both conditions can have a similar appearance, with sac-like structures, which is why encephalocele can resemble a cystic hygroma. Therefore, the statement "Encephalocele can resemble a cystic hygroma" is true.

Encephalocele is a condition where a portion of the brain protrudes through an opening in the skull. The most common location for this to occur is at the back of the skull, known as the occipital region. This is because the bones in this area are not fully formed until later in development, making it more susceptible to defects. Encephaloceles can also occur in the frontal or parietal regions, but the occipital region is the most common site.

Spina bifida is a type of neural tube defect where the spinal column does not close properly during fetal development. This can result in various degrees of physical and neurological disabilities, depending on the severity of the condition. Spina bifida can cause problems with mobility, bladder and bowel control, and may also lead to complications such as hydrocephalus. Treatment for spina bifida typically involves surgery to close the opening in the spine and manage any associated complications.

Anencephaly is the correct answer because it is a severe form of cranial neural tube defect (NTD) characterized by the absence of major portions of the cranium and intracranial structures. The presence of bulging eyes (orbits and face present), polyhydramnios, macroglossia, and a very short neck are also consistent with the features seen in anencephaly.

Encephalocele is a cranial neural tube defect characterized by abnormal openings in the skull, through which brain tissue protrudes. This condition is commonly associated with other abnormalities such as hydrocephalus, spina bifida, and polyhydramnios. An encephalocele can occur anywhere along the midline of the skull and may vary in size. It is typically diagnosed prenatally or at birth and may require surgical intervention to correct or manage complications.

Iniencephaly is a rare neural tube defect that is characterized by an extreme retroflexion of the head, exaggerated spinal lordosis, and cervical rachischisis (spina bifida). This condition is typically diagnosed during prenatal ultrasounds or at birth. Iniencephaly is a severe and often fatal condition, as it affects the development of the brain and spinal cord. The exact cause of iniencephaly is unknown, but it is believed to be a combination of genetic and environmental factors. Treatment options for iniencephaly are limited, and management typically involves supportive care to address any associated complications.

Neurulation is the process in embryonic development where the neural plate, which is a flat sheet of cells, folds inward to form the neural tube. This folding is crucial for the formation of the central nervous system, as the neural tube gives rise to the brain and spinal cord. Neurulation involves complex cellular movements and rearrangements, as well as signaling pathways that regulate the process.

A neural tube defect (NTD) refers to any defect in the development of the brain and spinal cord during pregnancy. These defects occur when the neural tube, which eventually forms the brain and spinal cord, fails to close properly. This can lead to various conditions such as spina bifida and anencephaly. Therefore, the correct answer is brain and spinal cord, as NTDs affect the development of these two crucial parts of the central nervous system.

Some of the risk factors associated with neural tube defects include poor nutrition, exposure to certain chemicals/radiation during pregnancy, and a history of NTD. Poor nutrition can lead to inadequate intake of essential nutrients like folic acid, which is crucial for neural tube development. Exposure to certain chemicals or radiation during pregnancy can increase the risk of neural tube defects. A history of NTD in the family also increases the likelihood of having a baby with a neural tube defect. Rh incompatibility between mother and fetus is not directly associated with neural tube defects.

The hollow center of the neural tube is referred to as the neural canal. The cranial end of the neural canal develops into the brain, while the caudal end develops into the spinal cord.

Acrania is a cranial NTD (neural tube defect) where there is a partial or complete absence of the skull cap (calvarium) but the brain develops abnormally. Sonographic findings in acrania would include the presence of brain tissue without any evidence of calvarium, inability to obtain BPD (biparietal diameter, a measurement used to assess fetal head size), and a floating brain. This indicates that the brain has developed fully but is abnormal in its structure or position.

The four "cranial" neural tube defects are acrania, anencephaly, encephalocele, and iniencephaly. Acrania refers to the absence of the skull bones, while anencephaly is the underdevelopment of the brain and skull. Encephalocele is the protrusion of brain tissue through a skull defect, and iniencephaly is a rare defect characterized by severe bending of the head and spine. These defects occur during early fetal development when the neural tube, which forms the brain and spinal cord, fails to close properly.

The explanation for the given correct answer is that NTDs (Neural Tube Defects) can involve either the cranial (head) or the spinal areas of the body. This means that they can affect the brain and skull (cranial) or the spinal cord and vertebrae (spinal). The answer provided includes both possibilities, stating that NTDs can be either cranial, spinal or spinal, cranial.

The three different degrees of spina bifida, from least severe to most severe, are occulta, meningocele, and meninomyelocele. Spina bifida occulta is the mildest form, where the spinal cord and nerves are usually undamaged and there may be a small gap in the spine. Meningocele is the middle degree, where the protective covering of the spinal cord protrudes through a gap in the spine, forming a sac filled with cerebrospinal fluid. Meninomyelocele is the most severe form, where the sac contains both the protective covering of the spinal cord and the spinal cord itself, leading to nerve damage and potential paralysis.