#Neuraltubedefects скачать в хорошем качестве

#Neuraltubedefects

Birth defects : most common are Embryonic precursor to the central nervous system Made up of the Brain & Spinal Cord Formation Of Neural Tube The human nervous system originates from the primitive ectoderm that also develops into the epidermis. By the 3rd week of development ,the edges of the neural plate start to thicken and lift upward , forming the Neural Folds & Neural Crest. The center of the neural plate remains grounded, allowing a U-shaped neural groove . The neural folds pinch in towards the midline of the embryo and fuse together to form the neural tube. The neural tube is open both cranially and caudally. These openings, called neuropores, close during the fourth week. Improper closure of the neuropores can result in neural tube defects. Embryology 2 processes form the C.N.S. 1-Neurulation – formation of structures into a tube thereby forming brain – spinal cord. 2-Neurulation – formation lower spinal cord lumbar and sacral elements Neural tube defects NTDs Account for the largest proportion of congenital anomalies of the CNS 1-3/1000 LB Result from failure of the neural tube to close spontaneously between the 3rd and 4th wk of gastation Dysraphism Group of disorder Resulting from failure of closure embryonic posterior and anterior neuropores Associated with abnormal development of other part of neural tube and bony & soft tissue structures Etiology Teratogens : Hyperthermia Sulfa Drugs Antihistaminics Anticonvulsivant Most strongly tied :Carbamazepine Valproic acid (folate antagon) - risk of 2% (NTD) Folate deficiency, Low red cell folate levels Malnutrition-Low Dietary Folic Acid Chemicals, Radiation Maternal obesity or diabetes Genetic determinants (mutations in folate-responsive or folate-dependent enzyme athways) Family history of NTDs Certain syndromes and chromosomal disorders. Low dietary low folic acid ANENCEPHALIC Results from failure of closure of the rostral neuropore large defect of the calvarium, meninges, and scalp Associated with a rudimentary brain. Only a residue of the brainstem can be identified. Additional anomalies Die within several day of birth ENCEPHALOCELE Part of brain and meninges herniated through congenital,traumatic or post surgical defect Cranial encephalocele : sac, cerebral cortex, cerebellum or portion of brainstem Most common is occipital frontal nasal Increased risk of Hydrocephalus (aqueduct stenosis) Chiari Malformation Dandy Walker syndrome Visual problems Microcephaly Mental retardation Seizures SPINA BIFIDA Spina bifida occurs during development prior to birth. When the spinal cord, brain, or meninges (their protective covering) does not completely develop. It can be anywhere along the spine and usually can be seen in an opening in the baby’s back at birth or a sack of fluid that has grown outside the body on the spine. This sack may or may not include the spinal cord inside. Spina bifida occulta A gap in between vertebrae No visible opening outside No fluid-filled sack outside the body Small birthmark or dimple on the back Small group or cluster of hair on the back An area of extra fat on the back Meningocele Small opening in the back Sack that’s visible at birth Membranes pushing out through the opening in the vertebrae into sack Normal development of the spinal cord Myelomeningocele Open spinal canal over some vertebrae (L5,S1) Membranes and spinal cord pushed outside in an exposed or skin-covered sack Weak or paralyzed leg muscles Seizures Deformed feet Hips that are not even Scoliosis (curved spine) Bowel and bladder Dysfunction Signs and Symptoms Radiologic Signs: Lamina Defects Hemivertebrae Scoliosis Widening of interpedicular Distance Butterfly Vertebrae Cutaneous Stigmata: Capillary Hemangioma Caudal appendage Dermal Sinus Q-1 The human nervous system originates from ? A- Primitive ectoderm B- Epidermis C- Endoderm D- All of the above Q-2 Most Common congenital disorder of CNS is ? A- Meningocele B- Myelomeningocele C- Spina bifida occulta D- Anencephaly E- Encephalocele Q-3 Anencephaly develop due to the non fusion of? A- Anterior neuropore B- Posterior neuropore C- Rostral neuropore D- Caudal neuropore Q-4 Prenatal Sereening of Neural tube defect done by ? A- Ultrasound examination : after 18 weeks of pregnancy. B- Maternal serum alpha-fetoprotein (MSAFP) test: High levels C- Amniotic fluid alfa-fetoprotein (AFAFP) test: Low levels D- Amniotic fluid acetylcholinesterase (AFAChE) test: Elevated levels E- All of the above Q-5 Complications of NTDs A- Infection B- Bowel & bladder dysfunction C- Paralysis D- All of the above