Discitis

 

What is Discitis?

The spine is made up of vertebrae, the bony building blocks of the back, separated by what are called inter-vertebral discs which are spongy discs which act as shock absorbers between the vertebrae. Discitis, as its name suggests, is inflammation of the discs, usually only one disc is affected but the inflammation may spread to adjacent discs. There are various causes for this inflammation, which are discussed below, and severe discitis can lead to permanent damage to the disc. It is a relatively rare condition.

 

Who gets Discitis?

Although adults can develop discitis, it is more common in children particularly between the ages of 2 and 7. Discitis is particularly rare in the elderly probably because, with age, the discs between the vertebrae become smaller and less spongy and therefore less prone to inflammation.

 

What is the cause of Discitis?

It is thought that there are a number of causes of discitis, the main one being infection. Discitis caused by infection is sometimes called ‘septic discitis’ and can be caused by the introduction of infection from a medical or surgical procedure such as an epidural (where a needle is inserted into the spine for the purposes of introducing an anaesthetic), back surgery or, for some reason, extensive bowel surgery.  Also for reasons that are not fully understood the existence of cancer or diabetes can be a factor in the existence of discitis.

Some cases of discitis are not caused by infection but by what is thought to be a chemical reaction to an injected substance such as cortisone which, ironically, may be injected as part of the treatment for certain types of back pain. Trauma such as a severe blow to the back is also thought to be a cause in some cases.

 

What are the symptoms of Discitis?

The main symptom of discitis is severe back pain as a result of the inflammation of the disc in question. This will often reduce the ability of the individual to walk and in children one of the symptoms may be a refusal to walk for reasons which may not be immediately apparent. Even if the child continues to walk they may be very reluctant to flex their spine, holding their back rigidly upright or even arching their back, since the act of bending increases their pain as a result of the increased pressure on the affected disc.

In cases where discitis is caused by infection, the individual may also have symptoms such as general ill health, headaches, and possibly a slight temperature.

Occasionally someone with discitis will suffer from symptoms of a trapped nerve similar to sciatica as a result of the inflammation of the disc causing similar inflammation of the nerve running alongside the spine.

 

How is Discitis diagnosed?

The doctor may initially suspect discitis from the history of the sudden onset of back pain in a child or adult for no obvious reason. The doctor would then examine the sufferer and find that they have a stiff, painful back with tenderness in one particular area of the back three quarters of which tend to be in the lumbar (low back) region and one quarter in the upper thoracic back. The patient may also have a slight temperature.

The doctor is likely then to organise blood tests including one called an ESR  (Erythrocyte Sedimentation Rate), which tests for inflammation and is often raised in cases of discitis. If the patient is admitted to hospital further blood tests may include cultures of the blood to look for the bacteria causing any infection. Further tests may include x-rays of the back and usually an MRI (Magnetic Resonance Image) of the spine which is particularly good at detecting discitis. Occasionally a bone scan will be done to look for ‘hot spots’ of inflammation in the spine. Very occasionally a biopsy (where a small amount of tissue is removed for analysis) is taken of the disc although this procedure is controversial.

 

How is Discitis treated?

The usual treatment for discitis is antibiotics. These are usually initially given intravenously (directly into a vein) because this makes the antibiotics more effective and then, as the individual recovers, they may be converted to antibiotics given by mouth and these may be continued for some time until the specialist is confident that the infection has been eradicated, Occasionally antibiotics are inserted under x-ray guidance directly into the infected disc.

Rest is usually recommended. In children this may include reducing the movements of the spine by putting the child in a back brace and in adults admission to hospital for rest sometimes for several weeks may be a significant part of the treatment.

In severe cases surgery may be required to remove part or the entire affected disc or to drain abscesses, which sometime occur beside the infected disc.