Central nervous system diseases or central nervous system disorders are a group of

neurological disorder Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...

s that affect the structure or function of 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 ...

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

, which collectively form the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...

(CNS). These disorders may be caused by such things as infection, injury, blood clots, age related degeneration, cancer, autoimmune disfunction, and birth defects. The symptoms vary widely, as do the treatments. Central nervous system tumors are the most common forms of pediatric cancer. Brain tumors are the most frequent and have the highest mortality. Some disorders, such as substance addiction,

autism Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...

, and

ADHD Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple ...

may be regarded as CNS disorders, though the classifications are not without dispute.

Signs and symptoms

Every disease has different signs and

symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

. Some of them are persistent headache; pain in the face, back, arms, or legs; an inability to concentrate; loss of feeling; memory loss; loss of muscle strength;

tremor A tremor is an involuntary, somewhat rhythmic muscle contraction and relaxation involving neural oscillations, oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the h ...

s; seizures; increased reflexes, spasticity, tics; paralysis; and slurred speech. One should seek medical attention if affected by these.

Causes

Trauma

Any type of traumatic brain injury (TBI) or injury done to the spinal cord can result in a wide spectrum of disabilities in a person. Depending on the section of the brain or spinal cord that experiences the trauma, the outcome may be anticipated.

Infections

Infectious diseases are transmitted in several ways. Some of these infections may affect the brain or spinal cord directly. Generally, an

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

is a disease that is caused by the invasion of a microorganism or virus.

Degeneration

Degenerative spinal disorders involve a loss of function in the spine. Pressure on the spinal cord and nerves may be associated with herniation or disc displacement. Brain degeneration also causes central nervous system diseases (i.e. Alzheimer's,

Lewy body dementia Lewy body dementia (LBD) is an umbrella term for two similar and common subtypes of dementia: dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Both are characterized by changes in thinking, movement, behavior, and mood. The ...

, Parkinson's, and

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly Genetic disorder#Autosomal dominant, inherited. It typically presents as a triad of progressive psychiatric, cognitive, and ...

s). Studies have shown that obese people may have severe degeneration in the brain due to loss of tissue affecting

cognition Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...

Structural defects

Common structural defects include birth defects, anencephaly, and

spina bifida Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the vertebral column, spine and the meninges, membranes around the spinal cord during embryonic development, early development in pregnancy. T ...

. Children born with structural defects may have malformed limbs, heart problems, and facial abnormalities. Defects in the formation of the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...

include microgyria, polymicrogyria, bilateral frontoparietal polymicrogyria, and pachygyria.

CNS Tumors

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

is an abnormal growth of body tissue. In the beginning, tumors can be noncancerous, but if they become malignant, they are cancerous. In general, they appear when there is a problem with cellular division. Problems with the body's

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

can lead to tumors.

Autoimmune disorders

An autoimmune disorder is a condition where in the immune system attacks and destroys healthy body tissue. This is caused by a loss of tolerance to proteins in the body, resulting in immune cells recognising these as 'foreign' and directing an immune response against them.

Stroke

A stroke is an interruption of the blood supply to the brain. Approximately every 40 seconds, someone in the US has a stroke. This can happen when a

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 ...

is blocked by a

blood clot A thrombus ( thrombi) is a solid or semisolid aggregate from constituents of the blood (platelets, fibrin, red blood cells, white blood cells) within the circulatory system during life. A blood clot is the final product of the blood coagulatio ...

or when a blood vessel ruptures, causing blood to leak to the brain. If the brain cannot get enough oxygen and blood, brain cells can die, leading to permanent damage.

Functions

Spinal cord

The spinal cord transmits sensory reception from the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of Bilateria, bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside t ...

. It also conducts motor information to the body's

skeletal muscles Skeletal muscle (commonly referred to as muscle) is one of the three types of vertebrate muscle tissue, the others being cardiac muscle and smooth muscle. They are part of the somatic nervous system, voluntary muscular system and typically are a ...

, cardiac muscles, smooth muscles, and

glands A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

. There are 31 pairs of

spinal nerves A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into ...

along the spinal cord, all of which consist of both sensory and motor

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s. The spinal cord is protected by

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e and connects the peripheral nervous system to the brain, and it acts as a "minor" coordinating center.

Brain

The brain serves as the organic basis of

and exerts centralized control over the other organs of the body. The brain is protected by the

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

; however, if the brain is damaged, significant impairments in cognition and physiological function or death may occur.

Diagnosis

Types of CNS disorders

Addiction

Addiction is a disorder of the brain's

reward system The reward system (the mesocorticolimbic circuit) is a group of neural structures responsible for incentive salience (i.e., "wanting"; desire or craving for a reward and motivation), associative learning (primarily positive reinforcement and c ...

which arises through transcriptional and

epigenetic In biology, epigenetics is the study of changes in gene expression that happen without changes to the DNA sequence. The Greek prefix ''epi-'' (ἐπι- "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in ...

mechanisms and occurs over time from chronically high levels of exposure to an addictive stimulus (e.g., morphine, cocaine, sexual intercourse, gambling, etc.).

Arachnoid cysts

Arachnoid cysts are

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ven ...

covered by arachnoidal cells that may develop on the brain or spinal cord. They are a

congenital disorder A birth defect is an abnormal condition that is present at childbirth, birth, regardless of its cause. Birth defects may result in disability, disabilities that may be physical disability, physical, intellectual disability, intellectual, or dev ...

, and in some cases may not show symptoms. However, if there is a large cyst, symptoms may include headache, seizures,

ataxia Ataxia (from Greek α- negative prefix+ -τάξις rder= "lack of order") is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in e ...

(lack of muscle control),

hemiparesis Hemiparesis, also called unilateral paresis, is the weakness of one entire side of the body (''wikt:hemi-#Prefix, hemi-'' means "half"). Hemiplegia, in its most severe form, is the complete paralysis of one entire side of the body. Either hemipar ...

, and several others.

Macrocephaly Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a Heredity, familial genetic characteristic. People diagnosed with macrocephaly will receive further medical ...

and

are common among children, while presenile dementia,

hydrocephalus Hydrocephalus is a condition in which cerebrospinal fluid (CSF) builds up within the brain, which can cause pressure to increase in the skull. Symptoms may vary according to age. Headaches and double vision are common. Elderly adults with n ...

(an abnormality of the dynamics of the cerebrospinal fluid), and

urinary incontinence Urinary incontinence (UI), also known as involuntary urination, is any uncontrolled leakage of urine. It is a common and distressing problem, which may have a significant effect on quality of life. Urinary incontinence is common in older women ...

are symptoms for elderly patients (65 and older).

Attention deficit/hyperactivity disorder (ADHD)

ADHD is an organic disorder of the nervous system. ADHD, which in severe cases can be debilitating, has symptoms thought to be caused by structural as well as biochemical imbalances in the brain; in particular, low levels of the neurotransmitters

dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...

and norepinephrine, which are responsible for controlling and maintaining attention and movement. Many people with ADHD continue to have symptoms well into adulthood. Also of note is an increased risk of the development of

Dementia with Lewy bodies Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior change (individual), behavior, cognition, movement, and dysautonomia, regulation of automatic bodily functions. Unlike some other dementias, mem ...

, or (DLB), and a direct genetic association of

Attention deficit disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple con ...

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

* two progressive, and serious, neurological diseases whose symptoms often occur in people over age 65.

Autism

Autism is a neurodevelopmental disorder that is characterized by repetitive patterns of behavior and persistent deficits in social interaction and communication.

Brain tumors

Tumors of the central nervous system constitute around 2% of all cancer in the United States.

Catalepsy

Catalepsy is a nervous disorder characterized by immobility and muscular rigidity, along with a decreased sensitivity to pain. Catalepsy is considered a symptom of serious diseases of the nervous system (e.g.,

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 ...

, etc.) rather than a disease by itself. Cataleptic fits can range in duration from several minutes to weeks. Catalepsy often responds to

Benzodiazepines Benzodiazepines (BZD, BDZ, BZs), colloquially known as "benzos", are a class of central nervous system (CNS) depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat co ...

(e.g.,

Lorazepam Lorazepam, sold under the brand name Ativan, Tavor among others, is a benzodiazepine medication. It is used to treat anxiety (including anxiety disorders), insomnia, severe agitation, active seizures including status epilepticus, alcoh ...

) in pill and I.V. form.

Encephalitis

Encephalitis is an inflammation of the brain. It is usually caused by a foreign substance or a

viral infection A viral disease (or viral infection) occurs when an organism's body is invaded by pathogenic viruses, and infectious virus particles (virions) attach to and enter susceptible cells. Examples include the common cold, gastroenteritis, COVID-19, t ...

. Symptoms of this disease include headache, neck pain, drowsiness, nausea, and fever. If caused by the

West Nile virus West Nile virus (WNV) is a single-stranded RNA virus that causes West Nile fever. It is a member of the family ''Flaviviridae'', from the genus ''Flavivirus'', which also contains the Zika virus, dengue virus, and yellow fever virus. The virus ...

, it may be lethal to humans, as well as birds and horses.

Epilepsy and seizures

Epilepsy is an unpredictable, serious, and potentially fatal disorder of the nervous system, thought to be the result of faulty electrical activity in the brain. Epileptic seizures result from abnormal, excessive, or hypersynchronous neuronal activity in the brain. About 50 million people worldwide have epilepsy, and nearly 80% of epilepsy occurs in developing countries. Epilepsy becomes more common as people age. Onset of new cases occurs most frequently in infants and the elderly. Epileptic seizures may occur in recovering patients as a consequence of brain surgery.

Infection

A number of different

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 (i.e., certain

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,

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 ...

protozoa Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically ...

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 ...

, and

prion A prion () is a Proteinopathy, misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death. Prions are responsible for prion diseases, known as transmissible spongiform encephalopathy (TSEs), w ...

s) can cause

s that adversely affect the brain or spinal cord.

Meningitis

Meningitis is an inflammation of the

meninges In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid spac ...

(membranes) of the brain and spinal cord. It is most often caused by a bacterial or viral infection. Fever, vomiting, and a stiff neck are all symptoms of meningitis.

Migraine

A chronic, often debilitating

characterized by recurrent moderate to severe headaches, often in association with a number of autonomic nervous system symptoms.

Multiple sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease, meaning that the

myelin sheath Myelin Sheath ( ) is a lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. The myelinated axon can be lik ...

s is damaged. Symptoms of MS include visual and sensation problems, muscle weakness, numbness and tingling all over, muscle spasms, poor coordination, and depression. Also, patients with MS have reported extreme fatigue and dizziness, tremors, and bladder leakage.

Myelopathy

Myelopathy is an injury to the spinal cord due to severe compression that may result from trauma, congenital stenosis, degenerative disease or disc herniation. The spinal cord is a group of nerves housed inside the spine that runs almost its entire length.

Tourette's

Tourette's syndrome is an inherited neurological disorder. Early onset may be during childhood, and it is characterized by physical and verbal

tics A tic is a sudden and repetitive motor movement or vocalization that is not rhythmic and involves discrete muscle groups. Tics are typically brief and may resemble a normal behavioral characteristic or gesture. Tics can be invisible to the obs ...

. Tourette's often also includes symptoms of both OCD and

indicating a link between the three disorders. The exact cause of Tourette's, other than genetic factors, is unknown.

Neurodegenerative disorders

Alzheimer's

Alzheimer's is a neurodegenerative disease typically found in people over the age of 65 years. Worldwide, approximately 24 million people have

dementia Dementia is a syndrome associated with many neurodegenerative diseases, characterized by a general decline in cognitive abilities that affects a person's ability to perform activities of daily living, everyday activities. This typically invo ...

; 60% of these cases are due to Alzheimer's. The ultimate cause is unknown. The clinical sign of Alzheimer's is progressive cognition deterioration.

Huntington's disease

Huntington's disease is a degenerative neurological disorder that is inherited. Degeneration of neuronal cells occurs throughout the brain, especially in the

striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamat ...

. There is a progressive decline that results in abnormal movements. Statistics show that Huntington's disease may affect 10 per 100,000 people of Western European descent.

Lewy body dementia

is an umbrella term for two similar and common subtypes of

dementia with Lewy bodies Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior change (individual), behavior, cognition, movement, and dysautonomia, regulation of automatic bodily functions. Unlike some other dementias, mem ...

(DLB) and Parkinson's disease dementia (PDD). Both are characterized by changes in thinking, movement, behavior, and mood. The two conditions have similar features and may have similar causes, and are believed to belong on a spectrum of Lewy body disease that includes

Parkinson's

Parkinson's disease, or PD, is a progressive illness of the nervous system. Caused by the death of dopamine-producing brain cells that affect motor skills and speech. Symptoms may include bradykinesia (slow physical movement), muscle rigidity, and tremors. Behavior, thinking, sensation disorders, and the sometimes co-morbid skin condition

Seborrheic dermatitis Seborrhoeic dermatitis (also spelled seborrheic dermatitis in American English) is a long-term skin disorder. Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin. Areas of the skin rich in sebum, oil-producing gland ...

are just some of PD's numerous nonmotor symptoms.

, Attention deficit/hyperactivity disorder (ADHD) and

Bi-polar disorder Bipolar may refer to: Astronomy * Bipolar nebula, a distinctive nebular formation * Bipolar outflow, two continuous flows of gas from the poles of a star Mathematics * Bipolar coordinates, a two-dimensional orthogonal coordinate system * Bipol ...

, all appear to have some connection to one another, as all three nervous system disorders involve lower than normal levels of the brain chemical

(In ADHD, Parkinson's, and the depressive phase of Bi-polar disorder.) or too much dopamine (in Mania or Manic states of

) in different areas of the brain:

Treatments

There are a wide range of treatments for central nervous system diseases. These can range from surgery to neural rehabilitation or prescribed medications. The most valued companies worldwide whose leading products are in CNS Care include CSPC Pharma (Hong Kong),

Biogen Biogen Inc. is an American multinational biotechnology company based in Cambridge, Massachusetts, United States specializing in the discovery, development, and delivery of the treatment of neurological diseases to patients worldwide. Biogen ope ...

(United States), UCB (Belgium) and Otsuka (Japan) who are active in treatment areas like MS, Alzheimers, Epilepsy and Psychiatry.

References

External links

{{Authority control Central nervous system disorders