Nervous system diseases, also known as nervous system or neurological disorders, refers to a small class of

medical condition A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

s affecting the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...

. This category encompasses over 600 different conditions, including genetic disorders, infections,

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...

disorders (such as

epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrica ...

), conditions with a cardiovascular origin (such as stroke), congenital and

developmental disorder Developmental disorders comprise a group of psychiatric conditions originating in childhood that involve serious impairment in different areas. There are several ways of using this term. The most narrow concept is used in the category "Specific Di ...

s (such as

spina bifida Spina bifida (Latin for 'split spine'; SB) is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, men ...

), and degenerative disorders (such as multiple sclerosis, Alzheimer's disease,

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

, and amyotrophic lateral sclerosis).

Signs and symptoms

Signs and symptoms can vary depending on the condition. Given the significance of the nervous system in human physiology, symptoms can involve other organ systems and result in motor dysfunction, sensory impairment, pain, etc.

Causes

Genetic

Some nervous system diseases are due to genetic

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA replication, DNA or viral repl ...

s. For example,

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is a neurodegenerative disease that is mostly inherited. The earliest symptoms are often subtle problems with mood or mental abilities. A general lack of coordination and an uns ...

is an inherited disease characterized by progressive neurodegeneration. Huntington's disease results from a mutation in either copy of the HTT gene, which results in an abnormally folded protein. The accumulation of mutated proteins results in brain damage of the basal ganglia.

Congenital/developmental defect

Developing babies can have

birth defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...

s that affect the formation of the nervous system. For example,

Anencephaly Anencephaly is the absence of a major portion of the brain, skull, and scalp that occurs during embryonic development. It is a cephalic disorder that results from a neural tube defect that occurs when the rostral (head) end of the neural tube ...

(or spina bifida) causes abnormalities in the nervous system due to

neural tube defect Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embryo b ...

Cancer

AFIP-00405562-GiantCellGlioblastoma-Gross

Specialized cells in the central nervous system, such as

glial cells Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. They maintain homeostasis, form myel ...

, may proliferate abnormally and form

glioma A glioma is a type of tumor that starts in the glial cells of the brain or the spine. Gliomas comprise about 30 percent of all brain tumors and central nervous system tumours, and 80 percent of all malignant brain tumours. Signs and symptoms ...

Glioblastoma Glioblastoma, previously known as glioblastoma multiforme (GBM), is one of the most aggressive types of cancer that begin within the brain. Initially, signs and symptoms of glioblastoma are nonspecific. They may include headaches, personality ...

is an aggressive form of glioma.

Infection

Pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

s like

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

, and

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsk ...

es can affect the nervous system. For example, meningitis is a common infection of the central nervous system, where bacterial or viral infections cause an inflammation of the meninges.

Seizure disorder

It is suspected that seizures occur because of synchronized brain activity.

Epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrica ...

, for example, is characterized by an abnormal electrical activity in the brain, which causes repeated seizures.

Vascular

The

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

is rich in

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

s because it requires a lot of nutrients and

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

. A stroke may result from a

blood clot A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of ...

hemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, v ...

Degenerative

A neurodegenerative disease is a disease that causes damage to neurons. Examples of neurodegenerative disease include Alzheimer's disease,

, and amyotrophic lateral sclerosis. For example, multiple sclerosis (MS) is an inflammatory neurodegenerative disease where the body initiate an inflammatory reaction in the central nervous system, and causes damage to neurons. Neurodegneration is different in each disease; for example, MS is a result of a degenerative process called

demyelination A demyelinating disease is any disease of the nervous system in which the myelin sheath of neurons is damaged. This damage impairs the conduction of signals in the affected nerves. In turn, the reduction in conduction ability causes deficiency i ...

. On the other hand, Parkinson's disease results from damage of neurons in the Substantia Nigra, which is important to initiate motor behavior.

Anatomy

Central nervous system (CNS)

According to Tim Newman, the central nervous system is made up of the brain and spinal cord, it collects information from the entire body and it also controls functions throughout the entire body.

Brain

Newman's research also shows that the brain is the most complex organ in the entire body. The brain is split up into 4 lobes: the temporal, parietal the occipital, and the frontal.The brain has over 100 billion neurons and it uses about 20% of the body's oxygen.

Spinal cord

The spinal cord runs through most of the back. The spinal cord contains a total of 31 spinal nerves in between each vertebra. The nerves connect to the peripheral nervous system.

Peripheral nervous system

The peripheral nervous system connects to the muscles and glands and sends information to the central nervous system.

Diagnosis

There are a number of different tests that can be used to diagnose neurological disorders.

Lumbar puncture

A lumbar puncture (LP), also known as a spinal tap, is a procedure where a hollow needle is inserted into the subarachnoid space of the spinal cord, allowing for the collection of

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the ...

(CSF) for collection and subsequent analysis. Red and white blood cell counts, protein and

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

levels, and the presence of abnormal cells or pathogens such as bacteria and viruses can all be screened for. The opacity and color of the fluid can also yield useful information that can assist in a diagnosis.

Treatments

The treatments for nervous system disorders varies depending on the condition, and can include interventions such as medication, surgery, and therapy.

References

External links

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