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Neural Tube Defects

Neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation defects (NTDs) are the 2nd-most common type of congenital Congenital Chorioretinitis birth defects. Neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation defects can range from asymptomatic (closed NTD) to very severe malformations of the spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy or brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification (open NTD). Neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation defects are caused by the failure of the neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation to close properly during the 3rd and 4th week of embryological development. The most common type of open NTD is meningomyelocele, which involves both the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy and neural tissue. The etiologies of NTD are multifactorial, ranging from maternal nutrition to genetic determinants. Prenatal diagnosis by ultrasound and maternal α-fetoprotein level is common. Management of open NTDs is mainly surgical.

Last updated: 8 Jan, 2021

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

A neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation defect (NTD; spinal dysraphism Dysraphism Teratogenic Birth Defects) is a congenital Congenital Chorioretinitis defect in the covering of the central nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification, resulting from a failure of the neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation to close spontaneously during the 3rd or 4th week of embryonic development.

Classification

  • Open NTD (80% of cases): a midline defect of the vertebral bodies with different degrees of protrusion of the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy and central nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification (CNS)
    • Defect along the spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy:
      • Meningocele: Only the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy protrudes.
      • Meningomyelocele: Both meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy protrude (most common NTD).
    • Defect of the cranium Cranium The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy:
      • Cranial meningocele: Meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy protrude.
      • Cranial encephalocele: Both the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy and brain stem Brain Stem The brain stem is a stalk-like structure that connects the cerebrum with the spinal cord and consists of the midbrain, pons, and medulla oblongata. It also plays a critical role in the control of cardiovascular and respiratory function, consciousness, and the sleep-wake cycle. Brain Stem: Anatomy/ cerebellum Cerebellum The cerebellum, Latin for “little brain,” is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum: Anatomy/ cerebral cortex Cerebral cortex The cerebral cortex is the largest and most developed part of the human brain and CNS. Occupying the upper part of the cranial cavity, the cerebral cortex has 4 lobes and is divided into 2 hemispheres that are joined centrally by the corpus callosum. Cerebral Cortex: Anatomy protrude. 
      • Anencephaly: complete failure of the cephalic neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation to close resulting in fully exposed fetal brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification (not compatible with life)
  • Closed NTD: a midline defect of the vertebral bodies without protrusion of the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy or neural tissue
    • Without subcutaneous mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast: spina bifida occulta
    • With subcutaneous mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
      • Lipomyelomeningocele
      • Lipomeningocele

Epidemiology

  • 1 in 1,500 births in the United States 
  • 2nd-most common major congenital Congenital Chorioretinitis anomalies (most common are cardiac Cardiac Total Anomalous Pulmonary Venous Return (TAPVR) anomalies)
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency:
    • Has decreased with prenatal folic acid supplementation and screening Screening Preoperative Care
    • Varies by ethnicity and geographic region
  • Female neonates are affected more commonly.
  • Maternal risk factors during pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care:
    • Folate Folate Folate and vitamin B12 are 2 of the most clinically important water-soluble vitamins. Deficiencies can present with megaloblastic anemia, GI symptoms, neuropsychiatric symptoms, and adverse pregnancy complications, including neural tube defects. Folate and Vitamin B12 deficiency 
    • History of NTD in previous children (5%10% recurrence with 12 affected siblings)
    • Folic acid-depleting medications ( valproic acid Valproic acid A fatty acid with anticonvulsant and anti-manic properties that is used in the treatment of epilepsy and bipolar disorder. The mechanisms of its therapeutic actions are not well understood. It may act by increasing gamma-aminobutyric acid levels in the brain or by altering the properties of voltage-gated sodium channels. First-Generation Anticonvulsant Drugs, triamterene Triamterene A pteridinetriamine compound that inhibits sodium reabsorption through sodium channels in renal epithelial cells. Potassium-sparing Diuretics, trimethoprim Trimethoprim The sulfonamides are a class of antimicrobial drugs inhibiting folic acid synthesize in pathogens. The prototypical drug in the class is sulfamethoxazole. Although not technically sulfonamides, trimethoprim, dapsone, and pyrimethamine are also important antimicrobial agents inhibiting folic acid synthesis. The agents are often combined with sulfonamides, resulting in a synergistic effect. Sulfonamides and Trimethoprim, sulfasalazine Sulfasalazine A drug that is used in the management of inflammatory bowel diseases. Its activity is generally considered to lie in its metabolic breakdown product, 5-aminosalicylic acid released in the colon. Sulfonamides and Trimethoprim)
    • Poorly controlled maternal diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Maternal obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity

Embryology

  • Conception to 3rd week of gestation ( gastrulation Gastrulation Both gastrulation and neurulation are critical events that occur during the 3rd week of embryonic development. Gastrulation is the process by which the bilaminar disc differentiates into a trilaminar disc, made up of the 3 primary germ layers: the ectoderm, mesoderm, and endoderm. Gastrulation and Neurulation): 
  • 3rd4th week:  
    • Ectoderm Ectoderm The outer of the three germ layers of an embryo. Gastrulation and Neurulation → differentiates into neuroectoderm Neuroectoderm Development of the Nervous System and Face (creating neural plate Neural plate The region in the dorsal ectoderm of a chordate embryo that gives rise to the future central nervous system. Tissue in the neural plate is called the neuroectoderm, often used as a synonym of neural plate. Gastrulation and Neurulation) → cell replication in neural plate Neural plate The region in the dorsal ectoderm of a chordate embryo that gives rise to the future central nervous system. Tissue in the neural plate is called the neuroectoderm, often used as a synonym of neural plate. Gastrulation and Neurulation →  neural crests + neural fold
    • Mesoderm Mesoderm The middle germ layer of an embryo derived from three paired mesenchymal aggregates along the neural tube. Gastrulation and Neurulation → differentiates into notochord Notochord A cartilaginous rod of mesodermal cells at the dorsal midline of all chordate embryos. In lower vertebrates, notochord is the backbone of support. In the higher vertebrates, notochord is a transient structure, and segments of the vertebral column will develop around it. Notochord is also a source of midline signals that pattern surrounding tissues including the neural tube development. Gastrulation and Neurulation  signals neural fold to enlarge/fuse →  neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation ( neurulation Neurulation An early embryonic developmental process of chordates that is characterized by morphogenic movements of ectoderm resulting in the formation of the neural plate; the neural crest; and the neural tube. Improper closure of the neural groove results in congenital neural tube defects. Gastrulation and Neurulation)
    • Neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation “zips up” from the middle outward → cranial (head) and caudal (tail) openings close approximately on days 24 and 28
Timeline neurulation

Neurulation Neurulation An early embryonic developmental process of chordates that is characterized by morphogenic movements of ectoderm resulting in the formation of the neural plate; the neural crest; and the neural tube. Improper closure of the neural groove results in congenital neural tube defects. Gastrulation and Neurulation: the differentiation and growth of the neural plate Neural plate The region in the dorsal ectoderm of a chordate embryo that gives rise to the future central nervous system. Tissue in the neural plate is called the neuroectoderm, often used as a synonym of neural plate. Gastrulation and Neurulation into the neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation during the first trimester of gestation.
PNS: Peripheral nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification

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Clinical Presentation

Most NTDs are discovered during prenatal screening Screening Preoperative Care. Open NTDs are evident at birth, but closed NTDs may have more subtle presentations.

Table: Clinical features of major neural tube Neural tube A tube of ectodermal tissue in an embryo that will give rise to the central nervous system, including the spinal cord and the brain. Lumen within the neural tube is called neural canal which gives rise to the central canal of the spinal cord and the ventricles of the brain. Gastrulation and Neurulation defects
Name Description Clinical features
Myelomeningocele Spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy and meningeal herniation Herniation Omphalocele The higher the lesion in the spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy, the more severe the symptoms:
  • Brainstem: type 2 Type 2 Spinal Muscular Atrophy Chiari malformation (cerebellar tonsillar herniation Herniation Omphalocele) with hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage
  • Neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess: quadriplegia Quadriplegia Severe or complete loss of motor function in all four limbs which may result from brain diseases; spinal cord diseases; peripheral nervous system diseases; neuromuscular diseases; or rarely muscular diseases. The locked-in syndrome is characterized by quadriplegia in combination with cranial muscle paralysis. Consciousness is spared and the only retained voluntary motor activity may be limited eye movements. This condition is usually caused by a lesion in the upper brain stem which injures the descending corticospinal and corticobulbar tracts. Locked-in Syndrome
  • Lumbosacral defect:
    • Paraplegia/flaccid paralysis
    • Loss of touch and pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways sensations in lower limbs
    • Anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts in perianal area
    • Bowel + bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess incontinence
Meningocele Meningeal herniation Herniation Omphalocele without spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy involvement
  • Fluctuant Fluctuant Dermatologic Examination mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
  • Transilluminates
  • Covered by skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
Encephalocele Meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy ± brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification tissue protruding from cranial defect
  • Hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage
  • Spasticity Spasticity Spinal Disk Herniation
  • Paralysis
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
  • Microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder
  • Developmental delay
  • Vision Vision Ophthalmic Exam problems
  • Developmental and growth retardation Growth Retardation Failure of a fetus to attain expected growth. Fetal Alcohol Spectrum Disorder
Anencephaly Major component of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy is absent.
  • Stillbirth/early death
  • Spastic with deafness/ blindness Blindness The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of eye diseases; optic nerve diseases; optic chiasm diseases; or brain diseases affecting the visual pathways or occipital lobe. Retinopathy of Prematurity
Spina bifida occulta Midline vertebral body Vertebral body Main portion of the vertebra which bears majority of the weight. Vertebral Column: Anatomy fusion defect without protruding dura or neural tissue
  • Usually asymptomatic
  • If spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy is involved (tethered cord syndrome), may develop incontinence, constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation, or ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia
  • May be accompanied by abnormal overlying skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions with a hemangioma Hemangioma A vascular anomaly due to proliferation of blood vessels that forms a tumor-like mass. The common types involve capillaries and veins. It can occur anywhere in the body but is most frequently noticed in the skin and subcutaneous tissue. Imaging of the Liver and Biliary Tract, discoloration, pit, lump, dermal sinus, or hairy patch Patch Nonpalpable lesion > 1 cm in diameter Generalized and Localized Rashes
Types of ntd and their respective defect

Types of NTD and their respective defect

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Diagnosis

Prenatal screening Screening Preoperative Care

  • Serum/amniotic α-fetoprotein (maternal serum α-fetoprotein; MSAFP): high levels at 1520 weeks of gestation suggestive of NTD, but not diagnostic
  • Ultrasound: Visualization of defect is 98% specific and can be used to confirm diagnosis (closed NTD may not be detected).

Postnatal imaging

  • Open NTD: ultrasound commonly used; magnetic resonance imaging (MRI) can be used if further detail required
  • Closed NTD: ultrasound indicated with following cutaneous signs:
    • Palpable subcutaneous mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
    • Hairy patch Patch Nonpalpable lesion > 1 cm in diameter Generalized and Localized Rashes overlying spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy
    • Dermal sinus
    • Dimples > 5 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma deep or > 25 mm MM Multiple myeloma (MM) is a malignant condition of plasma cells (activated B lymphocytes) primarily seen in the elderly. Monoclonal proliferation of plasma cells results in cytokine-driven osteoclastic activity and excessive secretion of IgG antibodies. Multiple Myeloma from anal verge
    • Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions tags or tail-like appendages
    • Hyperpigmented patches Patches Vitiligo or deviation of the gluteal cleft

Management

Prenatal

  • Prevention with folic acid (vitamin B9) supplementation:
    • Decreases the incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency of NTD by around 70%
    • Preconception dose: 0.4 mg/day of folic acid for at least 1 month prior to conception and throughout pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care 
    • A higher dose (usually 4 mg/day) is indicated for the following:
      • A previous pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care affected by an NTD
      • A positive family history Family History Adult Health Maintenance for NTD
      • Use of folic acid-depleting medications
      • Pre-gestational diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
  • Delivery: cesarean section recommended

Postnatal

  • Closed NTD: 
    • May require no intervention
    • Ongoing follow-up for lower neurological symptoms (incontinence, constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation, difficulty ambulating) 
  • Open NTD:
  • Surgical management:
    • Neurosurgical intervention for all open NTDs
    • Closed NTD typically does not require surgery

References

  1. Boon, R. L. (2010). Textbooks of Paediatrics.
  2. Winn, H. R. (2011). Youmans Neurological Surgery E-Book. Elsevier Health Sciences.
  3. Goetzl, L.M. Folic acid supplementation in pregnancy. UpToDate. Retrieved Nov 2, 2020, from https://www.uptodate.com/contents/folic-acid-supplementation-in-pregnancy?search=neural%20tube%20defects&topicRef=460&source=see_link#H17
  4. Dukhovny, S., Wilkins-Haug, L. Open neural tube defects: Risk factors, prenatal screening and diagnosis, and pregnancy management. UpToDate. Retrieved Nov 2, 2020, from https://www.uptodate.com/contents/open-neural-tube-defects-risk-factors-prenatal-screening-and-diagnosis-and-pregnancy-management?search=neural%20tube%20defects&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H27

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