Discitis
What is Discitis?
Discitis refers to inflammation or infection of the Intervertebral disk (specific
to the nucleus pulposus or endplate) with secondary involvement of the adjacent
cartilage and vertebral bone. This inflammatory or infectious process may lead to
disk erosion and significant pain.
Discitis occurs primarily in younger patients, and the lumbar spine is the most common
location. It is usually self-limiting and can be caused by an autoimmune process or secondary
to an invasive procedure (i.e. discography, myelography, lumbar puncture, paravertebral
injection, obstetrical epidural anesthesia etc.).
Risk factors
Include age greater than 50 years old, history of cancer, unexplained weight loss,
pain that lasts more than a month, history of IV drug abuse, presence of urinary
tract infection or other infections and recent invasive procedures.
Symptoms
Individuals typically complain of:
• Low back pain which is moderate to severe, and is exacerbated by virtually any motion of the spine
• Radiation of pain to the abdomen, hip, leg, scrotum, or groin
• Tenderness over the spine
• Paravertebral muscle spasms
• Loss of normal lumbar lordosis and limitation of spine motion
• Exacerbation of pain with standing, hip flexion or walking
How is discitis diagnosed?
Discitis has characteristic radiologic findings that help distinguish infection from
metastatic tumor. Destruction of the disc space is highly suggestive of infection,
whereas tumor will not cross the disc space. Bone scan is very sensitive but is a
non-specific investigation and does not always define the extent of the lesion.
Magnetic resonance imaging is considered to be a very sensitive investigation for
the diagnosis of discitis, especially in the very early stages of the disease.
Patients rarely have an elevated temperature and their white blood cell count is
frequently normal. However, the erythrocyte sedimentation rate is usually increased.
If the discitis is believed to be infectious an attempt should be made to obtain
direct cultures from the involved disc space. These may be obtained percutaneously
with CT or other radiographic guidance, or from intra-operative specimen. Blood
cultures may be positive in approximately 50% of cases.
What is the treatment for discitis?
Outcome is generally good, and medical treatment with immobilization is usually adequate.
Immobilization - Probably does not affect final outcome, but generally affords earlier pain
relief, and may allow return to activity at an earlier time. Most patients are started on
strict bed rest, and are fitted for a plastic-type body jacket in which they are allowed to
ambulate. This body jacket is worn for 6-8 weeks on average.
If the lesion is thought to be infectious, antibiotics will be used (the organism involved
is frequently Staphylococcus aureus, brucella, micrococci or fungi). Normally, the patient
will be treated with IV antibiotics for an arbitrary period of time, usually 4-6 weeks,
followed with oral antibiotics for an additional 4-6 weeks.
Surgery - the least common modality. Surgery is reserved for:
• Situations where the diagnosis is uncertain, especially when tumor is a possibility
• Decompression of neural structures, especially with associated spinal epidural abscess or compression by
inflammatory tissue, weakness, numbness, and bladder or bowel disturbance.
• Drainage of associated abscess
• Rarely, to fuse an unstable spine
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