Discitis is a medical condition where swelling occurs in spaces between the discs in the vertebrae, causing abnormal pressure on the discs and pain.
Discitis is a rare type of spinal inflammation that often occurs together with osteomyelitis, an infection that affects the bones and bone marrow. It most commonly affects the lumbar region, but may also affect the cervical and thoracic spine.
Discitis can also put the vertebral disc at risk. The disc is the largest avascular organ in the body, which means it does not have its own blood supply. If it becomes affected, it will be especially difficult for it to fight the infection since its main source of white blood cells is diffused through the vertebral end plates. This is why patients with discitis should be treated immediately to prevent serious complications.
Discitis cases are classified as either spontaneous or post-operative. The possible causes of spontaneous discitis include:
Abnormal autoimmune response
Infections that cause discitis do not always originate in the disk space or the vertebrae itself. Often, the infection spreads through the bloodstream towards the vertebral spaces (transient bacteremia). Most of the cases are associated with systemic infections, such as urinary tract infection, soft-tissue infection, and pneumonia. Such infections are most commonly caused by staphylococcus aureus, E.coli, and Proteus bacterial species.
Its risk factors include:
Weakened immune system
The use of intravenous drugs, which can either be due to IV drug abuse or IV needle contamination
Age - Discitis is more common in children under ten years old
Diseases that compromise a person’s immune system are also considered as risk factors for discitis. Examples are end-stage renal disease and diabetes mellitus.
Postoperative discitis, on the other hand, occurs as a post-surgical complication in around 1-2 percent of patients who undergo spinal surgery, the most common of which is a simple discectomy.
Discitis causes the following symptoms:
Pain in certain parts of the spine
Pain in the lower and upper back
Changes in posture
Difficulty performing regular tasks
The pain caused by discitis can be quite severe. In very young children, this may be especially difficult to manage and may lead to walking difficulties or abnormal back arching.
To determine whether these symptoms are caused by discitis and not by other similar conditions, doctors may perform a number of tests such as:
Bone scan - Use to detect a bone infection by examining the vertebrae as well as the spaces around them.
Blood tests, including a CBC (complete blood count) to detect infection
Magnetic resonance imaging – An MRI scan is the most conclusive and accurate diagnostic tool that can confirm a discitis diagnosis
Tissue analysis, in which the doctor takes a sample of the patient’s spinal tissue for further analysis
Discitis is treated by spine or lumbar specialists. The primary approach for treatment involves:
Medications - Antimicrobial drugs are prescribed to fight the infection and analgesics to achieve pain relief. Patients who undergo antibiotic therapy for discitis often require a standard treatment period of 6 to 8 weeks.
Drainage - If an abscess has already formed, treatment will also involve draining it to relieve the increased pressure on the spinal cord and stabilise the spine.
Steroids - Prescribed for severe or chronic discitis. Patients may also be advised to wear supportive equipment for the back, such as back braces to reduce the mobility of the affected region during recovery.
Bed rest, which may be necessary for some patients
Lifestyle changes, including changes to the patient’s daily activities
Gentle exercises for the unaffected parts of the body to prevent generalised body weakness
If the condition fails to improve, more aggressive treatments, including surgery can be recommended. Surgical procedures for the treatment of discitis may involve a percutaneous biopsy of the infected area.
The prognosis for patients suffering from discitis is heavily influenced by how early the condition is diagnosed and treated. If the condition is caused by an infection, the greatest risk is the development of sepsis or epidural abscess, which can occur if the infection spreads to other organs or the nervous system. This is more likely to occur if the treatment is delayed. Other potential complications of discitis, if not treated promptly, include intervertebral fusion and paralysis.
In conclusion, factors that can improve patient prognosis include:
Prompt use of MRI to ensure an accurate diagnosis
Prolonged antimicrobial therapy
Timely surgical intervention
Marcovici A. “Diskitis.” 2016 Jan 29. Medscape. http://emedicine.medscape.com/article/1263845-overview#a3
Parra JLC, Martin A SA, Urda Martinez-Aedo AL, Ivanez IS, Agredo A, Stern LLD. “Management of infectious discitis. Outcome in one hundred and eight patients in a University Hospital.” Int Orthop. 2012 Feb; 36(2): 239-244. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3282861/
Bajwa ZH, Ho C, Grush A, Kleefield J, Warfield CA. “Discitis associated with pregnancy and spinal anesthesia.” Anesth Analg. 2002 Feb; 94(2): 415-6. https://www.ncbi.nlm.nih.gov/pubmed/11812710