What is Nontraumatic Spinal Cord Injury?

Nontraumatic Spinal Cord Injury (NTSCI) is any damage to the spinal cord that has not been caused by a major trauma. So rather than the spinal cord being injured in a traumatic impact like a car crash or a fall, it has been damaged in other ways such as infection, loss of blood supply, compression by a cancer or through slow degeneration of the spinal bones (vertebrae) such as in osteoarthritis.
The spinal cord is about 46cm long, and contains many nerve cells that create signals, nerve fibres that transmit the signals as well as other cells that look after the nerve cells. Around the spinal cord are a stack of bones known as the vertebrae that provide support and protection for the delicate nerve cells inside.
The spinal cord acts as a connector between the brain and the body; the brain sends signals out through nerves that run down the spinal cord, and from there other nerves go out into the body. These control things like movement of muscles, but also other functions such as sweating, urination and defecation. The body also sends signals up through the spinal cord to the brain via other nerves giving information about touch, temperature, position and pain.
This delicate cord can be damaged anywhere along its path. The effects of the injury will depend on where in the spinal cord the damage occurred. When the cord is damaged, the nerve cells above that level are usually still okay, but below that level they can no longer communicate with the brain. If the damage is high up then there can be more loss than if the injury was lower in the spinal cord. This means the brain can no longer send or receive information to or from the parts of the body supplied by levels of cord at or below the level of injury, meaning it is unable to control movement or feel any sensations.
In a nontraumatic spinal injury, something has happened that has stopped this connection. There are lots of things that can cause a nontraumatic injury, and many of these are listed below. What are more important however, are the many complications that can arise from an NTSCI, and these are covered under Natural History.

Statistics

The number of nontraumatic spinal cord injuries is difficult to know because there are so many different causes, and there is no one big registry where all the information is kept. While it is thought that in the United States there are between 183 000 and 230 000 people with traumatic spinal cord injuries, it is thought that if you included nontraumatic cases then this number would more than quadruple.
In Australia, the rate is thought to be about the same as overseas, with a rate of nearly 31 injuries for every million people per year; twice that of traumatic injuries.

Risk Factors

One of the major factors that predisposes to NTSCI is simply age, the older you are the more likely it is to have an injury of this type. This is because many of the causes (listed below) increase with age. For this reason, as our population ages and a greater percentage of people are in an older age bracket, it is likely that the number of nontraumatic spinal cord injuries will begin to rise.
To understand the factors that can predispose to nontraumatic spinal cord injury, it is important to first understand what the many causes are.

Causes

Causes of NTSCI can be divided into five categories:

    1. Vascular: this makes up about 25% of all NTSCI and these causes are due to things that involve blood and the blood vessels. Examples of this include:
      • Epidural Haemorrhage: bleeding into the area around the spinal cord can compress the nerves and cause damage
      • Severe Hypotension: if the heart cannot pump blood well enough, then sometimes the blood pressure can fall so low that not enough blood gets to the spinal cord, causing damage.
      • Cardiac arrest: can cause the heart to stop pumping blood efficiently, leading to a loss of blood supply to the cord
      • Atherosclerosis: a build up of fatty plaque in the vessels leading to the cord can block blood supply. This could be thought of as like a ‘heart attack’ of the spinal cord.
      • Embolism: a clot can break off from somewhere in the body – usually the heart – and block off the arteries that supply and area of the spinal cord.
    2. Neoplastic (Cancerous): This makes up another 25% of all NTSCI. Around 5% of all cancers can lead to spinal cord compression, either from local cancers in the bone or cord or having spread (metastasised) from another location:
      • Vertebral cancers can either have spread from another site, or can cause local damage such as with myeloma.
      • Most cancers that compress the cord are ones that have spread from another site. The most common cancers that spread to the spine are lung, breast, prostate, lymphoma, thyroid or melanoma.
      • Cancers can also form from the structures inside or surrounding the spinal cord and this can also compress it and cause damage. Examples of these include meningiomas (cancers of the membrane covering the spinal cord) and gliomas (cancers of supporting cells)
    3. Inflammatory and Infections: these account for about 20% of all NTSCI injuries. Damage is from big masses of inflammatory cells or localised areas of infection:
      • Epidural abscess: a build up of pus and bacteria outside the spinal cord can cause compression and damage
      • Tuberculosis: TB causes localised areas of inflammation and growth that leads to compression.
      • Granuloma: a granuloma is a localised area of inflammation that does not go away and can be caused by a condition like Sarcoidosis
      • Transverse Myelitis: a condition where a previous infection leads to a loss of a protective coating that covers nerve cells. This can lead to poor signal transmission through the nerves.
    4. Degenerative: these conditions are due to general breakdown due to wear and tear or other damaging process occurring to the bones and accounts for about 18% of all NTSCI.
    5. Other: There are also many other conditions that cause NTSCI, and these make up the remaining 12% of cases:

Progression

While the initial loss of muscle control and sensation can be devastating for a patient with NTSCI, there are also other long term issues that are frequently associated with them. The most common of these are recurrent urinary tract infections, and urinary incontinence can also occur. This may or may not be related to these infections. Other complications can include a condition called spasticity, where some muscles of the body are continuously contracted. Sexual issues such as impotence can be a problem as well.
Other common complications include chronic pain, depression, infections of the lungs, constipation and pressure ulcers. Pressure ulcers are due to immobility and lack of sensation, where areas of skin that press against a surface for too long can lose blood supply and start to die and may get infected.
Less common but no less important complications can include sleep disturbances and deep vein thrombosis, where long term immobility can cause blood clots to form in the legs.
Women may have some specific difficulties including issues of menstrual hygiene, pregnancy and breastfeeding.

Symptoms

If you have an NTSCI, then the doctor will firstly want to work out what the most likely cause of the injury is. Some of the things a doctor may ask about could be:

  • Signs of infections including fever, pain, tiredness as well as associated medical problems such as diabetes, kidney disease, drug and alcohol use.
  • Signs and symptoms of osteoporosis, including back pain, loss of height and spinal deformities such as kyphosis.
  • Looking for risk factors such as a history of previous fracture, history of fracture in a primary relative, family history of osteoporosis, oestrogen deficiency as a result of menopause, low intake of calcium, Vitamin D, use of certain medications (corticosteroids, chemotherapy can also aid diagnosis.
  • Symptoms of Spinal Stenosis include back pain, buttock pain, leg pain, limping, lack of feeling in lower extremities.
  • Symptoms for cancers include loss of weight, loss of appetite, malaise, fever, back pain, leg weakness, changes in sensation, loss of bowel/bladder control.

After the cause has been discovered, then questions from a doctor will more likely be asking about the complications of the injury, which have been discussed previously. They will probably ask about bladder and bowel functioning, insomnia, muscle contractions, ulcers and lung problems. They will also want to ask some sensitive questions about sexual functioning and depression, and it is important that these be asked and answered truthfully as there is often help available for many of these problems. These questions will probably be asked quite regularly in a patient with NTSCI because changes in any of these are important, and catching things before they become too much of a problem can result in better outcomes.

Clinical Examination

Again, the examination will depend on whether the doctor already knows the cause of the NTSCI or not. If they are still trying to find a cause, then they may test many of your nerves for function. They can do this by testing the tone and power of the muscles, reflexes, as well as testing sensation. The areas of weakness and loss of sensation can give clues about the level of the lesion. They may also check temperature, pulse rate and breathing rate. They may also want to feel your spine for any localised areas of pain. Inspecting the spine can look for any signs of deformity.
More importantly, a doctor would frequently want to check for any complications following an NTSCI:

  • The doctor will want to close inspect the skin, especially over pressure points. This is done to look for signs of infection and pressure ulcers.
  • They may want to inspect the calf muscles, which are common sites for deep vein thrombosis.
  • A thorough inspection of all muscle groups can be done to assess for any increase in tone (spasticity and contractures)
  • Blood pressure should be taken to assess for hypotension
  • It may be worth taking urine specimens for culture as urinary infection is very common

How is it Diagnosed

The doctor may decide to do some of the following tests, to help determine the reason for your disease:
Lab Studies

  • Blood can be taken to look for any signs of infection (raised white cell count, these cells help the body fight off infection) and haemoglobin (substance helping carry oxygen around the body) can be measured to detect any signs of blood loss or anaemia. The blood can also be cultured to identify the source and organism producing the infection.

Imaging Studies:

  • X-ray: This uses a series of rays to take a photograph of the spine, which can reveal vertebral problems, tumours, fractures or degenerative changes in the spine.
  • CT: A CT scan may give a better picture of abnormalities seen on an X-ray. This scan uses computers to form a series of cross sectional images to display bone and disc problems.
  • MRI: MRI scans use magnetic forces and radio waves to produce computer-generated images. This scan is the best type for looking at the spinal cord tissue and identifying masses that may be compressing the cord, any blood clots or herniated discs.

Myelography

  • Myelography involves a x-ray film being taken after a special dye is injected into the spinal canal. Myelography can demonstrate distortions of the spinal cord, the space within which it lies, and the spinal nerve roots connected to it.

Prognosis

The outcomes for patients with NTSCI can depend on the underlying cause of the lesion, as well as how complete the damage is. Overall though, prognosis is quite good, with around 76% of people who are admitted to hospital with a nontraumatic spinal injury being discharged home, and many more being adequately cared for in nursing homes or elsewhere in the community. The length of stay in hospital tends to depend on the type and severity of the lesion, with less complete damage resulting in a faster discharge. The length of stay in a hospital is generally still quite long though, with an average of 56 days stay for rehabilitation.

Treatment

The main treatment for patients with NTSCI is rehabilitation is a major hospital or other main health centre. Preferably, this is done somewhere that specialises in rehabilitation of NTSCI, and this is often joined with specialists in traumatic spinal injury into a ‘spinal care unit’. Traumatic and nontraumatic cases seem to stay in hospital for about the same amount of time before discharge.
In rehabilitation there are several key aspects. These include education about coping with the injury and prevention of complications, specialised wheelchair and seating prescription and bladder training. This will be combined with physiotherapy designed to keep the muscles working and other treatments to make patients as independent as possible.
Other areas of treatment in patients with NTSCI include:

    • Treating the underlying cause of your injury

 

  • Minimizing further damage to the spinal cord

 
 

  • Stabilising the spine to prevent further damage

 
Specific Treatment for Causes of Injury:

    • Infections: Treatment for spinal infections can be conservative, involving use of intravenous antibiotic injections into the veins, bracing the spine and rest. In advanced cases, surgery may be necessary to decrease the pressure on your the spine, clean out the infected area, and/or stabilize the spine.
    • Spinal Stenosis: In most cases of advanced stenosis, a surgical procedure to decompress the spine may be required. Decompression often results in an unstable spine, so the vertebrae may need to be fused together, to prevent worsening deformity and injury.
    • Cancer: Treatments for spinal cancers varies depending on the type of tumour, it’s location, and your co-existing medical conditions. Modalities of treatment options include chemotherapy, radiotherapy and/or surgical removal of the tumour.

References

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