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Discitis is a serious but uncommon medical diagnosis. It is an infection of the intervertebral disc space. The role of the intervertebral discs is to separate and cushion the spinal segments from each other. An infection, and thus inflammation of these discs can cause much pain and discomfort. What makes the condition uncommon is also what makes it difficult to treat: the relatively scarce blood supply to these segments. This activity explains when this condition should be considered in a differential diagnosis, articulates how to properly evaluate for this condition, and highlights the role of the interprofessional team in caring for patients with this condition. Objectives: Describe the causes of discitis. Outline the presentation of a patient with discitis. Summarize the treatment options for discitis. Review the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by discitis. Access free multiple choice questions on this topic.

Diskitis is a serious but uncommon medical diagnosis. It is an infection of the intervertebral disc space. See Image Diskitis. The role of the intervertebral discs is to separate and cushion the spinal segments from each other. An infection and thus inflammation of these discs can cause severe pain and discomfort. What makes the condition uncommon is also what makes it difficult to treat: the relatively scarce blood supply to these segments. Treatment consists of a prolonged antibiotic course, but usually results in uncomplicated resolution of symptoms; however, delay in treatment or misdiagnosis can lead to significant morbidity and mortality.

In the majority of cases, diskitis stems from 1 of 3 inciting events: direct inoculation, hematogenous spread, or, less commonly, contiguous spread.[1] Identification of the causative agent is difficult, if not impossible, at times.[2] A single organism is usually the cause.[3] When positive cultures are obtained, the most commonly identified organism is Staphylococcus aureus.[2][3] Also implicated, although less frequently, are coagulase-negative Staphylococcus, Escherichia coli, Streptococcus pneumoniae, and Salmonella spp.[2] Fungi have also been causative agents.[2] Hematogenous spread of disease, such as systemic infection or bacteremia, can first seed the vertebrae, followed by the disc, leading to subsequent infection.[2] Sites of origin include the urinary tract, pneumonia, and other soft-tissue infections. Also, contiguous spread from a local infection, such as adjacent osteomyelitis, to the vertebrae is another potential etiology, as is any spinal surgery, diagnostic procedure (eg, lumbar puncture), or local treatment (eg, injections into the area). The spinal arteries supply blood to the vertebrae and, eventually, to the intervertebral discs. In children, the blood vessels extend from the cartilaginous endplates into the nucleus pulposus, whereas in adults these vascular supplies degenerate and extend only into the annulus fibrosus.[2][4][5] The venous system, on the other hand, forms a plexus in the epidural space.[2] The lumbar spine is most commonly involved, followed by the cervical and then the thoracic spines.[1][2][3]

The incidence of diskitis in the United States is around 0.4 to 2.4 per 100,000 people each year.[3] Overall, diskitis is more common in pediatric patients than in adults, thought to be due to the intervertebral discs' vascular supply, which diminishes with age.[4] However, there is a bimodal age distribution, as incidence again increased around age 50.[3] It is also more common in males than in females.[3] In children, diskitis is part of a continuum of diseases that includes diskitis, spinal osteomyelitis, and soft-tissue abscesses.[6] In children alone, there is a higher incidence in early childhood, with another peak during adolescence.[4] Over half of the cases occur in patients with predisposing medical conditions, most commonly diabetes mellitus.[1] Other risk factors identified include age, immunocompromised individuals, intravenous drug users, alcoholics, hepatic cirrhosis, malignancy, and renal dysfunction.[4]

As always, history and physical examination are paramount in making an accurate and timely diagnosis. The symptoms depend on the patient's age, and early diagnosis can be difficult. Reports of delays of up to 6 months in diagnosis exist.[2] In the pediatric population, reports of back pain, refusal to walk, and even abdominal pain are common presenting complaints.[6] Diskitis in children has a more acute onset than in adults. In adults, common presenting complaints include back or neck pain, fever, weight loss, anorexia, and neurologic deficit.[3] Unlike some other causes of back pain, the pain of diskitis usually localizes to the disc level without radiation elsewhere. Postoperatively, symptoms typically occur 1 to 16 weeks after surgery.[3] The physical exam should elicit point tenderness over the involved disc, with the lumbar region most commonly affected.[1][3] There may be a limited or painful range of motion; however, lower extremity muscle strength, reflexes, and sensation are usually preserved. A neurologic deficit is uncommon, but it may be present in a smaller percentage of cases.[1]

Early diagnosis is often difficult, primarily because the laboratory and initial imaging tests are unremarkable. Significant laboratory findings in diskitis included elevations in ESR and CRP.[3] The white blood cell count may be normal. Blood cultures should be obtained to guide antibiotic treatment, although many patients are culture-negative.[7] Plain film radiographs are mostly unhelpful.[7] Radiographic findings usually do not manifest until a few weeks into the disease. Positive findings include narrowing of the disc space and destruction of adjacent vertebral segments.[2] MRI is the most sensitive and specific test for diagnosis.[2][3][4][7] A biopsy can be used for histologic confirmation and to obtain a culture of the causative organism.

Experts do not agree on the specific treatment of diskitis. Treatment options range from immediate broad-spectrum antibiotics to awaiting cultures for sensitivity before administering antibiotics, to spinal bracing alone without antibiotics.[3][7][8] Most commonly, the treatment of diskitis includes antibiotics, with surgery used less often. The antibiotic should be specific to the causative agent once known.[2][4] Initially, broad-spectrum antibiotics are suitable until culture results are available, allowing the agent to be narrowed. It is important to initially cover for Staphylococcus species. The course of antibiotics ranges from 4 to 6 weeks.[7] Patients should also be immobilized to allow fusion of the vertebral segments in proper anatomical alignment, which is accomplished by bed rest and a brace.[3] Pain control is also an important consideration during treatment. Early detection usually can negate the need for surgical intervention. When needed, surgery usually involves debridement.[9] Indications for surgery include neurologic deficits, spinal deformity, and refractory disease.[1][3]

Differential diagnoses for diskitis include common causes of back pain and less common infectious causes. These include, but are not limited to: Osteomyelitis Spinal tumors Spinal epidural abscess Spinal fracture Muscle or tendon injury Disc herniation Inflammatory spondyloarthropathies

Overall, mortality rates from diskitis range from 2 to 11%.[3] Children recover better with treatment and have less morbidity than adults.[2][3][10] Most patients are cured with antibiotics alone or with the addition of surgery. Some patients experience permanent neurologic disability, which usually results from a delay in diagnosis.[2]

Complications from diskitis include spinal deformity, segmental abnormality, and, less commonly, neurologic deficits.[2] Neonates suffering from the disease can have significant kyphosis.[6] The course overall in children, however, is generally benign.[10]

Deterrence of diskitis is difficult. Infections can often start elsewhere and spread to the disc space. Preventing and treating infections in other areas of the body would be of importance. Infection prevention is vital in diabetics and the immunocompromised, especially, as the disease is most prevalent in these populations.

Key facts to keep in mind about diskitis include the following: Diskitis is a serious but uncommon cause of back pain It is more common in children than adults, has a male predilection, and targets diabetics and immunocompromised patients Diagnosis is often delayed due to the commonality of back pain and unremarkable lab and imaging tests MRI is the gold standard of diagnostic testing It is usually bacterial Treatment consists of antibiotics, immobilization, and, less commonly, surgery Although complete resolution is the most common outcome, neurological deficits can complicate the disease process

There are few studies on diskitis and other infections of the spinal column due to the rarity of the disease and the usually delayed diagnosis. Early recognition is ideal and provides patients with the best outcome. Healthcare providers, including primary care providers, emergency department physicians, orthopedic surgeons, and rheumatologists, must therefore be aware of the broad differential diagnosis of back pain and of presentations across different age groups, including children and neonates, given the disease's predilection for those age groups. Appropriate consultations should be ordered, especially when systems persist without a confirmed diagnosis. Overall management includes all of the above specialists in an interprofessional team approach, along with specialty-trained nursing for pediatric and infectious disease as appropriate, and infectious disease pharmacy specialists.