Nervous system diseases, also known as nervous system or neurological disorders, refers to a small class of
medical conditions affecting the
nervous system
In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...
. This category encompasses over 600 different conditions, including genetic disorders, infections,
cancer
Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...
,
seizure disorders (such as
epilepsy
Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
), conditions with a cardiovascular origin (such as
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
), congenital and
developmental disorders (such as
spina bifida), and degenerative disorders (such as
multiple sclerosis
Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ...
,
Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...
,
Parkinson's disease, 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, and pain, among other things.
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 or viral replication, ...
s. For example,
Huntington's disease 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 defects that affect the formation of the nervous system.
For example,
Anencephaly (or spina bifida) causes abnormalities in the nervous system due to
neural tube defects.
Cancer

Specialized cells in the central nervous system, such as
glial cells, may proliferate abnormally and form
gliomas.
Glioblastoma is an aggressive form of glioma.
Infection
Pathogen
In biology, a pathogen (, "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 theory of d ...
s like
fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
,
bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
, and
virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...
es can affect the nervous system. For example,
meningitis
Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...
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 disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
, for example, is characterized by an abnormal electrical activity in the brain, which causes repeated seizures.
Vascular
The
brain
The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...
is rich in
blood vessel
Blood vessels are the tubular structures of a circulatory system that transport blood throughout many Animal, animals’ bodies. Blood vessels transport blood cells, nutrients, and oxygen to most of the Tissue (biology), tissues of a Body (bi ...
s because it requires a lot of nutrients and
oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
. A
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
may result from a
blood clot or
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, ...
.
Degenerative

A neurodegenerative disease is a disease that causes damage to neurons. Examples of neurodegenerative disease include
Alzheimer's disease
Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...
,
Parkinson'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.
Neurodegeneration is different in each disease; for example, MS is a result of a degenerative process called
demyelination.
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
The brain is the most complex organ in the human body. It is split up into two hemispheres, each split into four lobes: frontal, parietal, the temporal, and occipital. The brain has over 100 billion neurons and it consumes up to 20% of the energy used by the body.
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 (CSF) for collection and subsequent analysis. Red and white blood cell counts, protein and
glucose
Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...
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.
See also
*
Central nervous system disease
*
Peripheral neuropathy
References
*
External links
{{Authority control
Neurology