Neurological disorders

A neurologic disorder is caused by a dysfunction in the brain or nervous system (i.e. spinal cord and nerves). This dysfunction can result in physical and psychological symptoms.

The brain begins developing before birth. It continues developing throughout infancy, childhood, and adolescence. Most brain cells form before birth. One type of cell is the neuron, or nerve cell. Trillions of connections exist between neurons. These do not develop until infancy.

Neurologic disorders involve the brain, spinal column, and nerves. Symptoms depend on where damage occurs. Affected areas may control:

• Movement
• Sensation
• Communication
• Vision
• Hearing
• Thinking
• Emotion

Neurologic disorders are wide-ranging. They have various causes, complications, and outcomes. Many require life-long management.

Neurological disorders are diseases of the central and peripheral nervous system. In other words, the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscles.

These disorders include epilepsy, Alzheimer’s disease, and other dementias, cerebrovascular diseases including stroke, migraine, and other headache disorders, multiple sclerosis, Parkinson’s disease, neuro infections, brain tumours, traumatic disorders of the nervous system due to head trauma, and neurological disorders because of malnutrition.

Many bacterial (i.e., Mycobacterial tuberculosis, Neisseria meningitides), viral (i.e., Human Immunodeficiency Virus (HIV), Enteroviruses, West Nile Virus, Zika), fungal (i.e. Cryptococcus, Aspergillus), and parasitic (i.e. malaria, Chagas) infections can affect the nervous system. Neurological symptoms may occur due to the infection itself, or due to an immune response.

There are more than six hundred neurological disorders. The most common are:

• diseases due to defective genes, such as muscular dystrophy or Huntington’s disease
• degenerative diseases, such as Alzheimer’s or Parkinson’s
• diseases of the blood vessels that supply the brain, such as stroke
• problems in the development of the nervous system, such as spina bifida
• brain or spinal cord injury
• convulsive disorders, such as epilepsy
• brain tumours
• infections, such as meningitis

Types of symptoms include:

• Physical
• Cognitive (or thinking)
• Emotional
• Behavioural

Specific disorders have combinations or clusters of these symptoms. For example, cerebral palsy tends to have more physical symptoms. ADHD tends to affect behaviour more.

Many neurologic disorders emerge during the early years of development. They may be diagnosed at birth. Some are diagnosed later. Symptoms may only appear when:

• A child misses developmental milestones or has developmental difficulties (such as with autism)
• A damaging infection occurs (such as with meningitis)
• An accident causes brain injury (such as with a stroke, or trauma)

Prognosis of the disease

The prognosis of a neurological disorder can change significantly depending on the disease. In the case of degenerative diseases of the nervous system, such as Alzheimer’s, they can become quite severe over time, and can eventually put the patient’s life at risk. Some genetic diseases are also progressive, but if spotted early on can often be treated effectively.

In the case of convulsive disorders, such as epilepsy, the prognosis is usually better. A patient with epilepsy can generally manage their symptoms through treatment, although this may take several years.

Some forms of brain or spine injury are life-threatening, as are cardiovascular conditions such as stroke. A brain tumour can sometimes be benign, but if it is cancer, it requires timely treatment to improve the chance of survival.

Causes of neurologic disorders

Many neurologic disorders are congenital. This means they are present at birth. Some disorders are acquired. This means they develop after birth. Those with an unknown cause are called idiopathic.

Congenital Causes

Genetic factors can influence the development of some neurologic disorders. A child typically inherits them through genes and chromosomes, but these genetic changes are not always inherited from the parents – this is called de novo.

Chromosomes are long strands of DNA supported by protein. They exist in the centre of cells. Genes are sections of DNA. They carry the chemical code that makes us who we are. Chromosomes are composed of thousands of genes.

A human cell normally contains 46 chromosomes (23 pairs). A child inherits half from their mother and half from their father.

Congenital causes of neurologic disorders include:

• Gene abnormalities
• Chromosome abnormalities
• Metabolic abnormalities
• Congenital abnormalities

Prenatal and Perinatal Causes

A neurologic disorder can be caused during pregnancy (prenatal). It can also be caused throughout the period before, during, and after birth (perinatal). Such causes include:

• Toxins and environmental factors
• Nutritional deficiencies
• Infections
• Hypoxia/asphyxia
• Complications during childbirth
• Prematurity/ low birth weight
• Interaction effects

Acquired Causes

• Acquired causes develop after birth. They are less common than congenital causes. They include:
• Immune disorders
• Postnatal infections
• Traumatic brain injury
• Spinal cord injury
• Neoplasm
• Toxins

Symptoms

Neurological disorders can cause a wide range of symptoms, including:

• headaches
• numbness or loss of strength in a limb
• dizziness
• fainting and loss of consciousness
• memory problems
• cognitive difficulties
• speech problems
• vision problems
• tremors, spasms, and involuntary contractions

Medical tests for neurological disorders

Medical tests may vary depending on the affectation that the patient has. There are multiple tests to evaluate the state of the nervous system, which are more useful depending on what one wants to check. The following should be highlighted:

• Electroencephalogram: is especially useful in brain tumours or brain or spinal cord inflammation, for example.
• Cerebral angiography: used to locate vascular irregularities in the brain. They can be obstructions in the blood vessels or strokes, among others.
• Computed tomography: very effective in the detection of epilepsy, brain tumours or cysts, brain damage by injury, etc.
• Magnetic resonance: this reveals to the doctor the details of organs, tissues, nerves, and bones.
• Lumbar puncture: to obtain samples of cerebrospinal fluid and thus check the existence of bleeding or cerebral haemorrhages.

Can neurological disorders be prevented?

 In many cases, neurological disorders are difficult to prevent, especially when they are due to hereditary factors. However, there are a number of lifestyle changes that can reduce the risk of stroke, and which are thought to reduce the risk of developing dementia later in life:

• do some physical exercise on a regular basis
• avoid social isolation by keeping up with family and friends and getting involved in your local community
• avoid the consumption of alcohol, tobacco, and illegal drugs
• get a good night’s sleep (6-8 hours a day)
• maintain a balanced diet with plenty of fruit and vegetables
• avoid brain injuries by using the necessary protection on the road or when doing extreme sport
• avoid medical risk factors such as high blood pressure, high cholesterol, stress, exhaustion, obesity, or diabetes

Treatments for neurological disorders

There are multiple treatments for neurological disorders, which can vary depending on the condition. Normally, the main treatment consists of neurorehabilitation, which aims to restore, minimize, or compensate for functional deficits that the patient may have, but setting realistic expectations as to what is possible.

In some cases, it is possible to mitigate some symptoms with medication or surgery. Overall, treatment aims to improve the quality of life of patients suffering from a neurological disorder, so that they can have the greatest possible independence. In all neurological disorders, an early diagnosis is vital, so that the specialist can establish the most appropriate treatment in each case.

Source: www.who.int, https://www.childneurologyfoundation.org, https://www.topdoctors.co.uk