Neuritis: Types, Causes, Infections, Toxins and Medication, Symptoms and Treatment

It is a broad term used to describe various diseases that involve the inflammation of a nerve or a group of nerves.

It is often associated with pain, changes in sensations, weakness, numbness, paralysis or muscle wasting.

Neuritis along with other diseases that damage the peripheral nerves are collectively known as neuropathies.

Types of neuritis

Several types of neuritis have been identified. The most common types of neuritis are peripheral neuritis and optic neuritis. There are many other less common varieties of neuritis, which include:

  • Neuritis braquial.
  • Multiple polyneuritis.
  • Neuritis intercostal.
  • Neuritis cubital.
  • Neuritis lumbosacra.
  • Neuritis occipital.
  • Neuritis vestibular.
  • Neuritis craneal.
  • Arsenic neuritis
  • Motor sensory polyneuropathy.
  • Granulomatous neuritis of leprosy.

Causes of neuritis

In most patients with neuritis, the exact cause generally remains uncertain. Neuritis is seen more frequently with advancing age (55 years or older) and in women.

Diseases that affect the blood supply to the nerves and the deficiency of certain nutrients are important among the factors that can contribute to the development of neuritis.

The various causes of neuritis include:

  • Injury: The nerve injury causes inflammation and, subsequently, the symptoms of neuritis appear. There are several types of injuries that are usually localized and involve individual nerves. The various agents that cause nerve injuries are:
  • Physical damage: Compression of a nerve or direct injury from a penetrating injury to the nerve can cause inflammation. Carpal tunnel syndrome is a typical example of nerve compression and subsequent nerve injury.
  • This can cause pain and numbness of the thumb and index finger. The use of high-heeled shoes that lead to compression of the nerves that supply the fingers is another example of a compression injury. This can cause pain and numbness of the affected fingers.
  • Chemical damage: Nerve injuries can arise as a result of damage to adjacent structures and can cause the release of harmful substances that produce chemical neuritis.
  • The administration of some medications through injections can cause chemical damage to the nerves that are very close to the injection site.
  • Neuritis can develop as a side effect of certain medications used in chemotherapy. Chemical neuritis can also result from metallic poisoning such as arsenic poisoning.
  • Radiation injury: Radiation injury to the nerve may develop after radiation therapy for several types of cancer. Brachial neuritis or plexopathy is a known complication of radiotherapy of the upper area of ​​the chest.
  • Nutritional deficiencies
  • Neuritis is considered commonly associated with various nutritional deficiencies. Deficiencies of vitamin B such as vitamin B1 (thiamine), B2 (riboflavin), B6 ​​(pyridoxine) or B12 (cyanocobalamin) are often associated with peripheral neuritis.


Several infections can cause neuritis, for example:

  • Leprosy.
  • Lyme’s desease.
  • Syphilis.
  • Cat-scratch disease.
  • Diphtheria.
  • Chickenpox.
  • Herpes simplex infection.
  • Predisposing diseases.

Several conditions of diseases can lead to neuritis. This includes :

  • Diabetes mellitus.
  • Hypothyroidism
  • Porphyria
  • Autoimmune diseases such as Multiple Sclerosis, Sarcoidosis and Systemic Lupus Erythematosus.
  • Beriberi (caused by Thiamin deficiency).
  • Pernicious anemia.
  • Chronic acidosis
  • Certain types of cancers.
  • Some types of neuritis are genetically transmitted, including:
  • Hereditary optic neuropathy of Leber (LHON).
  • Amyloid polyneuropathy.
  • Charcot-Marie-Tooth disease.

Toxins and medication

Neuritis can develop as a result of the toxicity of certain environmental pollutants, metals, drugs and other chemicals.

Insecticides (such as Endosulfan), mercury, lead, arsenic, methanol, chronic alcoholism and Etambutol (antibiotics) are some of the substances that can cause neuritis as a result of their toxic effects.

It can also be seen as long-term side effects of some of the medications for cholesterol (side effects of statins), blood pressure and arthritis. Excessive intake of pyridoxine is also associated with neuritis.

Signs and symptoms

The symptoms of neuritis depend on the nerve or group of affected nerves. The common symptoms of neuritis usually located in the affected area include:

  • Pain – stabbing or puncture.
  • Muscle weakness (paresis)
  • Paresthesia (abnormal sensation) can be in the form of tingling or burning sensation.
  • Numbness of the neuritis, loss of sensitivity (anesthesia), swelling, reddening of the skin, paralysis, muscle wasting and loss of muscular reflexes can be observed.
  • Patients suffering from optic neuritis may have visual disturbances of varying degrees. It may be blurred or distorted vision in some patients, while in others it may be a loss of vision.
  • Some patients may suffer loss of color vision or eye pain. Some patients may have trouble adapting to bright light or darkness.

The most common cases of neuritis can be:

  • Neuritis Optica:

Optic neuritis is the inflammation of the optic nerve of the eye. The optic nerve transmits light signals from the back of your eye to your brain so you can see. If the optic nerve is swollen, damaged or infected, it can not see clearly.

Doctors do not know for sure what causes optic neuritis. This condition can be caused by the body’s immune system attacking the optic nerve tissue by mistake.

It seems more likely to happen in people who have had viral problems such as mumps, measles, flu or multiple sclerosis, among others.

You may have optic neuritis in one or both eyes. Symptoms may appear suddenly or develop gradually over a few days. They can include:

  • Blurry vision.
  • Dim vision, as if someone had turned off the lights.
  • The colors appear dull and faded.
  • Pain in the back of the eye socket.
  • Pain when you move your eyes.

The symptoms of optic neuritis can get worse when you are hot or very tired. For example, you may notice more symptoms when you exercise or bathe.

If optic neuritis is not treated, your symptoms may get worse. If you have symptoms of optic neuritis, talk to your ophthalmologist.

Some people get better without any treatment for optic neuritis. However, many people need treatment to improve vision or, at least, prevent the symptoms from getting worse.

The most common treatment is a medicine called Corticosteroids. For most people, taking Corticosteroids helps improve their vision a lot. Sometimes, it can even help the vision return to what it was before optic neuritis.

However, for people with multiple sclerosis or other conditions, treatment usually does not return your vision to what it was before optic neuritis.

It is very important to consult an ophthalmologist if you have symptoms of optic neuritis. The treatment can prevent the symptoms from getting worse and may save your vision.

  • Neuritis Vestibular

Vestibular neuritis is a disorder that affects the inner ear nerve called the Vestibulocochlear nerve. This nerve sends balance information and position of the head from the inner ear to the brain.

When this nerve becomes inflamed (inflamed), it disrupts the way in which information would normally be interpreted by the brain.

Vestibular neuritis can occur in people of all ages, but is rarely reported in children.

The Vestibulocochlear nerve sends balance information and position of the head from the inner ear to the brain. When the nerve swells, the brain can not interpret the information correctly. This causes a person to experience symptoms such as dizziness and vertigo.

What are the symptoms of Vestibular Neuritis?

Symptoms include:

  • Sudden and severe vertigo (sense of rotation / swing).
  • Dizziness.
  • Difficulties of balance.
  • Nausea vomiting.
  • Difficulties of concentration

Vestibular Neuritis and Labyrinthitis are closely related disorders. Vestibular Neuritis consists of inflammation of a branch of the Vestibulocochlear nerve (the Vestibular portion) that affects balance.

Labyrinthitis consists of inflammation of both branches of the Vestibulocochlear nerve (the vestibular portion and the cochlear portion) that affects balance and hearing.

The symptoms of Labyrinthitis are the same as Vestibular Neuritis plus the additional symptoms of Tinnitus (ringing in the ears) and / or hearing loss.

Generally, the most severe symptoms (severe vertigo and dizziness) only last a couple of days, but while they are present, they make it extremely difficult to perform routine daily activities.

After severe symptoms subside, most patients experience a slow but complete recovery during the following weeks (approximately three weeks).

However, some patients may experience balance problems and dizziness that can last for several months.

What causes Vestibular Neuritis?

Researchers think that the most likely cause is a viral infection of the inner ear, swelling around the vestibulocochlear nerve (caused by a virus) or a viral infection that has occurred somewhere else in the body.

Some examples of viral infections in other areas of the body include the herpes virus (cause cold sores, shingles, chicken pox), measles, flu, mumps, hepatitis and polio.

  • Neuritis intercostal

Intercostal Neuritis is a painful disorder of the nerves that runs between the ribs and is caused by damage to one of the nerves and / or loss of nerve function.


The intercostal nerves run between the ribs and can be damaged in several ways. The most common cause is chest surgery, during which a nerve can be damaged.

Signs and symptoms

In the Intercostal Neuritis, an acute sharp pain is felt in the chest, radiating from front to back (or vice versa). Continuous nervous pain can also be felt.

The skin may be painful to the touch and there is a greater sensitivity to pinching pain. The skin may also have a decreased sensitivity.

How is Intercostal Neuritis diagnosed?

If the symptoms appear after an operation, the diagnosis is usually clear.

If this is not the case, then other causes must be excluded. Therefore, an extensive neurological examination is important if you have chest pain.

Do I need an additional exam?

The diagnostic test of other non-physical factors important to your pain was already performed after completing the pain questionnaires.

Radiographs and an MRI are performed to exclude other causes.

You may be referred to a pulmonologist or an internal specialist.

What are my chances of treatment?

Depending on the cause of your pain, your pain specialist will decide whether or not to perform physical treatment.