Other Neurological Conditions
This section doesn't talk about multiple sclerosis (MS), but rather other neurological conditions or disorders. It's important to understand the basics of other disorders if one wants to better understand about MS. There are differences and similarities with each disorder and those can vary significantly between each person affected.

Neurological disorders are health conditions that involve the nervous system and causes paralysis to any part of the body. Sometimes physical injury to the brain, spinal cord, or nerves can be the cause of neurological disorders and sometimes they can result from biochemical causes. Other times, the cause may be unknown and only the effects are seen. Neurological disorders can also be a sign that there is an imbalance of some type in your system, but when you have an imbalance, you are also susceptible to various diseases which can settle in weak areas of your body.

Neurological disorders are a group of disorders that involve the central nervous system (CNS), the peripheral nervous system (PNS) including the cranial nerves, and the autonomic nervous system which is located in both CNS and PNS.

Neurological disorders are quite diverse, chronic, challenging to treat, and often disabling. They can be caused by many different factors, including inherited genetic abnormalities, problems in the immune system, injury to the brain or nervous system, or diabetes. Many mental illnesses are believed to be neurological disorders of the CNS, but they are classified separately. They aren't traditionally listed as neurological diseases because their causes are not definitely determined as biological, although there are good reasons to suspect that some have neuro-chemical causes.

Neurological disabilities are associated with damage to the nervous system (including the brain and spinal cord) that results in the loss of some bodily or mental functions. Acquired Brain Injury (ABI), and Epilepsy are two of the most prevalent neurological disabilities. Heart attacks, infections, genetic disorders, and lack of oxygen to the brain may also result in a neurological disability.

The CNS along with the PNS comprise a primary division of controls that command all physical activities of a vertebrate. Neurons of the CNS affect consciousness and mental activity while spinal extensions of CNS neuron pathways affect skeletal muscles and organs in the body.

The immune system defends the body against foreign invaders such as bacteria and viruses. It does so by recognizing that foreign invaders have special markers distinguishing them as "non-self," compared to the body's own tissue or "self." Normally, the immune system reacts only to non-self invaders, not to its own tissues. This, however, is not always the case. Autoimmunity is an immune response mounted against antigens that are naturally produced within the body, or self-antigens, to cause lasting tissue damage.

In the strictest sense, an autoimmune disease must meet several criteria. First, the disease must be reproduced by transfer of autoantibodies or autoreactive T lymphocytes (T cells) from affected to unaffected individuals. Second, the self-antigen that elicits the immune attack must be identified. Third, this antigen (or a closely related one) should cause a similar disease in an animal model.

There are several human and animal diseases of known etiology or pathogenesis that resemble either the clinical or the pathological features of MS. CNS demyelinating diseases include those mediated by immune responses, infection, and toxins, as well as inherited disorders. Infectious agents can induce direct injury of oligodendrocytes and their myelin membranes, as well as indirect injury via the immune system.

A variety of toxins, such as diphtheria, lysolecithin, cuprizone, and ethidium bromide, have been associated with demyelinating lesions. Many of these toxins induce lysis of the oligodendrocyte, with demyelination as a secondary effect. In addition, nutritional deprivation can be associated with demyelination in the CNS and PNS.
Neurological Conditions and Diseases
Alzheimer's disease

Alzheimer's disease (AD) is an irreversible, progressive disorder in which brain cells or neurons deteriorate, resulting in the loss of cognitive functions, primarily memory, judgment and reasoning, movement coordination, and pattern recognition. In advanced stages of the disease, all memory and mental functioning may be lost. A person with Alzheimer's disease usually has a gradual decline in mental functions, often beginning with slight memory loss, followed by losses in the ability to maintain employment, to plan and execute familiar tasks, and to reason and exercise judgment. The ultimate cause or causes of Alzheimer's disease are still unknown; there are several risk factors that increase a person's likelihood of developing the disease.

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease, is a disease in which certain nerve cells in the brain and spinal cord slowly die. These nerve cells are motor neurons, and they control the muscles that allow you to move the parts of your body. Those with ALS gradually become more disabled, but how quickly the disease gets worse is different for everyone. Some people live with ALS for several years. Over time, ALS makes it difficult to walk, speak, eat, swallow, and breathe. These problems can lead to injury, illness, and eventually death.

Acquired Brain Injury

Acquired Brain Injury (ABI) occurs when a sudden, external, physical assault damages the brain. It's one of the most common causes of disability and death in adults. ABI is a broad term that describes a vast array of injuries that occur to the brain. The damage can be focal (confined to one area of the brain) or diffuse (occurs in more than one area of the brain). The severity of a brain injury can range from a mild concussion to a severe injury that results in coma or even death. Acquired brain injuries are also commonly referred to as traumatic brain injuries (TBI).

Bell's palsy

Bell's palsy is a paralysis or weakness of the muscles on one side of your face. Damage to the facial nerve that controls muscles on one side of the face causes that side of your face to droop. The nerve damage may also affect your sense of taste and how you make tears and saliva. In most cases, the nerve that controls muscles on one side of the face is damaged by inflammation. A person's speech can be affected and sound "slurred" due to the effects of paralysis.

Carpal tunnel syndrome

Carpal tunnel syndrome occurs when tendons in the wrist become inflamed after being aggravated. Tendons can become aggravated when the carpals and the ligaments in the wrist narrow, pinching nerves that reach the fingers and the muscle at the base of the thumb. Repetitive flexing and extension of the wrist may cause a thickening of the protective sheaths that surround each of the tendons, which narrows the tunnel. Women are three times more likely to develop CTS than men, and the risk increases with age. People between the ages of 40 and 60 are more commonly affected.

Cerebral palsy

Cerebral palsy (CP) is a group of disorders associated with developmental brain injuries that occur during fetal development, birth, or shortly after birth. It's characterized by a disruption of motor skills, with symptoms such as spasticity, paralysis, or seizures. Cerebral palsy is also known as static encephalopathy and Little's disease (which is strictly speaking only the "spastic diplegia" form of CP). It's no longer considered a disease, but rather it is a chronic nonprogressive neurological disorder. The incidence is about 1.5 to 4 per 1000 live births. There is no cure, but therapy may be helpful. It has one of the highest lifetime costs of any birth defect.

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is an illness characterized by prolonged, debilitating fatigue and multiple nonspecific symptoms such as headaches, recurrent sore throats, muscle and joint pain, memory and concentration difficulties. Profound fatigue, the hallmark of the disorder, can come on suddenly or gradually and persists or recurs throughout the period of illness. Unlike the short-term disability, chronic fatigue syndrome symptoms linger for at least six months and often for years. The cause of chronic fatigue syndrome remains unknown.

Epilepsy

Epilepsy is a chronic neurological disorder in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally. In epilepsy, the normal pattern of neuronal activity becomes disturbed, causing strange sensations, emotions, and behavior or sometimes convulsions, muscle spasms, and loss of consciousness. Epilepsy is a disorder with many possible causes. Anything that disturbs the normal pattern of neuron activity - from illness to brain damage to abnormal brain development - can lead to seizures. Epilepsy may develop because of an abnormality in brain wiring, an imbalance of nerve signaling chemicals called neurotransmitters, or some combination of these factors. The seizures are transient signs and/or symptoms of abnormal, excessive or synchronous neuronal activity in the brain.

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a rare nervous system disorder that results from nerve damage caused by the body's immune system, usually in response to an infection or other illness. As the immune system produces antibodies to fight the infection or illness, it may also produce antibodies that attack the myelin sheath of the peripheral nerves and sometimes the nerve fibers or axons. The resulting nerve damage leads to tingling and numbing sensations, muscle weakness, and paralysis. GBS causes muscle weakness, loss of reflexes, and numbness or tingling in the arms, legs, face, and other parts of the body. It may also progress to complete paralysis.

Headaches

A headache is a condition of mild to severe pain in the head or sometimes upper back or neck pain may also be interpreted as a headache. Most headaches are due to tension, migraine, or a combination of the two. Serious underlying causes of headaches, like a tumor or a stroke, are extremely rare, despite the fact that many people worry about these possibilities. Migraine headache is a primary headache disorder with, almost certainly, a genetic basis. Activation of a mechanism deep in the brain causes release of pain-producing inflammatory substances around the nerves and blood vessels of the head.

Meningitis

Meningitis is an infection of the meninges, which is the coverings around the brain and spinal cord. The infection occurs most often in children, teens, and young adults. Also at risk are older adults and people who have long-term health problems, such as a weakened immune system. There are two main kinds of meningitis: Viral meningitis is fairly common and it usually doesn't cause serious illness. It can, however, cause prolonged fever and seizures. The other is bacterial meningitis isn't as common but is very serious. It needs to be treated right away to prevent brain damage and death.

Neuropathy

Neuropathy is the disease of the nervous system. Neuropathy is a disturbance in the function of a nerve or particular group of nerves. Many people who have had diabetes for a while have nerve damage. The three major forms of nerve damage are: peripheral neuropathy, autonomic neuropathy, and mononeuropathy. The most common form is peripheral neuropathy, which mainly affects the feet and legs. Neuropathy can lead to disability, amputation, decreased ambulation as well as foot and leg ulceration because of loss or damage to nerves which feel sensation in the lower limbs.

Parkinson's disease

Parkinson's disease is a neurodegenerative disease of the substantia nigra which is an area in the basal ganglia. Parkinson's disease involves a breakdown of the nerve cells in the motor area of the brain. As the cells break down, there is a shortage of dopamine. Dopamine is a neurotransmitter, or chemical that carries messages to the body. When there is a shortage of dopamine, the messages that regulate movement aren't sent properly. Parkinson's disease happens when nerve cells or neurons in a part of the brain called the substantia nigra gradually die. These cells normally produce dopamine, a chemical that helps to relay messages between areas of the brain that control body movement.
Other Demyelinating Diseases
ADEM

Acute disseminated encephalomyelitis (ADEM), also known as post vaccination encephalomyelitis, occurs as a consequence of vaccination with neural antigens. EAE, the most widely used animal model of MS, is the animal counterpart of this human disease. ADEM is characterized pathologically by widespread perivenular inflammation and demyelination. The uniformity of lesions differs from the multi-age lesions found in even the most acute case of MS. Post vaccination immune-mediated damage can also affect the PNS.

This disorder usually develops after a viral infection. Acute disseminated encephalomyelitis is thought to be a misguided immune reaction triggered by the virus. In the United States, this disorder usually results from some types of influenza, hepatitis A or B, or infection with enteroviruses, Epstein-Barr virus, or human immunodeficiency virus (HIV). Measles, chickenpox, and rubella used to be common causes before childhood vaccination became widespread.

Typically, the inflammation develops 1 to 3 weeks after the viral illness begins. It can be treated with corticosteroids given intravenously. Guillain-Barré syndrome seems to be a similar disorder of the peripheral nerves.

Adrenoleukodystrophy and Adrenomyeloneuropathy

Both are rare hereditary metabolic disorders. Adrenoleukodystrophy affects young boys, usually between the ages of 4 and 8. A milder, more slowly developing form of the disorder can begin in adults in their 20s or 30s. Adrenomyeloneuropathy affects adolescent boys.

In these disorders, widespread demyelination is accompanied by adrenal gland dysfunction. Boys have behavioral problems and problems with hearing and vision. Eventually, mental deterioration, involuntary and uncoordinated muscle contractions (spasticity), and blindness occur.

No cure for either disorder is known. Dietary supplements with glycerol trioleate and glycerol trierucate (known as Lorenzo's oil) have not been shown to slow the progression of the disease. Bone marrow transplantation is an experimental treatment.

Systemic inflammatory or autoimmune diseases

Multifocal CNS lesions can occur as a component of an array of systemic collagen vascular disorders including systemic lupus eryhemtosus and polyarteritis nodosa. The CNS manifestations may be the presenting feature. The PNS is also frequently involved.

HTLV-1 myelopathy

Human T cell lymphotropic virus type I (HTLV-1) infection is sometimes associated with a neurological syndrome called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Patients with HAM/TSP have a progressive myelopathy, usually with spastic paraparesis, sensory disturbance, bladder dysfunction, and occasionally, optic neuritis.

Leber's Hereditary Optic Neuropathy

This disorder causes demyelination leading to partial blindness. The disorder is more common among men. Usually, symptoms begin between the ages of 15 and 35. This disorder is inherited through the mother, and the defective genes seem to be located in mitochondria (structures in cells that provide energy for the cell).

No treatments are available. But limiting consumption of alcohol, which may affect the mitochondria, and not using tobacco products may help.

Schilder's Disease

Schilder's disease is a rare progressive demyelinating disorder which usually begins in childhood. Symptoms may include dementia, aphasia, seizures, personality changes, poor attention, tremors, balance instability, incontinence, muscle weakness, headache, vomiting, and vision and speech impairment. Schilder's disease is not the same as Addison-Schilder disease (adrenoleukodystrophy) and is a variant of MS.

Treatment for the disorder follows the established standards in MS and includes corticosteroids, beta-interferon or immunosuppressive therapy, and symptomatic treatment.

As with MS, the course and prognosis of Schilder's disease are unpredictable. For some individuals the disorder is progressive with a steady, unremitting course. Others may experience significant improvement and even remission and in some cases, Schilder's disease is fatal.

Tropical Spastic Paraparesis

Also called HTLV-associated myelopathy, this disorder causes demyelination in the spinal cord and results from infection with the human T cell lymphotropic virus (HTLV). The disorder worsens over several years. Gradually, the legs become weak and muscle spasms occur—a condition called spastic weakness. Frequent, strong urges to urinate, urinary incontinence, and bowel dysfunction also develop.

No cure is available, but corticosteroids may help, as may interferon-beta or immune globulin given intravenously (these drugs help prevent the immune system from attacking myelin sheaths). Muscle relaxants such as baclofen or tizanidine help relieve spasms.

Neuromyelitis Optica

Also called Devic disease, this disorder causes symptoms similar to those of MS and for a time was considered a variant of MS. However, neuromyelitis optica typically affects only the eyes and the spinal cord, and MS also affects the brain.

Neuromyelitis optica causes inflammation of the optic nerve (optic neuritis). One or both eyes may be affected. The disorder causes episodes of eye pain and dim, blurred, or lost vision. Days to weeks (sometimes years) later, the limbs are affected. People may temporarily lose sensation, and the arms and legs may become weak and sometimes paralyzed. People may be unable to control of bladder and bowel function.

In some people, the part of the spinal cord that controls breathing is inflamed, leading to difficulty breathing, which is life threatening.

The disorder progresses differently in each person. As the disorder progresses, people may have brief, frequent, painful muscle spasms. Eventually, blindness, loss of sensation and muscle weakness in the limbs, and bladder and bowel dysfunction may become permanent.

To diagnosis the disorder, doctors evaluate the nervous system (neurologic examination) during a physical examination. The optic nerve is examined with an ophthalmoscope. Tests include magnetic resonance imaging (MRI) and a blood test to detect specific antibodies in people with neuromyelitis optica.

There is no cure, however treatments can stop episodes, control symptoms, and prevent episodes from recurring. A corticosteroid (such as methylprednisolone) and a drug that suppresses the immune system (an immunosuppressant, such as azathioprine) are often used to stop and prevent episodes. Rituximab, a relatively new drug, may be used to reduce the number of abnormal antibodies and to control disorder. Plasma exchange (plasmapheresis) may help people who do not respond to corticosteroids. For this treatment, blood is removed, then abnormal antibodies are removed, and the blood is returned to the person.