OrthoNeuroSpine & Pain Institute

• Discitis is an infection of the disc space and vertebral endplate that is caused by hematogenous or postoperative inoculation.
• It affects intervertebral discs of the spine.
• The lower lumbar discs are most commonly involved.
• However, the infection may occur in any disc.
• Classification:
• Spontaneous (hematogenous)
• Iatrogenic (after discectomy or discogram)
• Epidemiology
• Hematogenous infection is uncommon.

The mean age of occurrence of hematogenous (spontaneous) discitis is 7 years, but it may affect individuals of any age.

Incidence

The incidence of infection after discectomy is <1%.

Risk Factors

• Compromised host (patients with diabetes, alcohol abuse, transplants)
• Intravenous drug abuse
• Procedures involving the disc (discography, discectomy, spinal anesthesia)

• Bacterial infection:
• The causative organism most commonly is Staphylococcus, except in the compromised host or intravenous drug abuser, in whom Gram-negative aerobic bacteria and Candida are more common (for these patients, biopsy is indicated).
• Vascularity issues in children <8 years old:
• The blood supply to the disc comes from the adjacent vertebral body.
• Vessels cross the cartilaginous endplate in children until they are approximately 8 years old, and the resultant vascularity renders younger children susceptible to infection in the area.

Associated Conditions

Vertebral osteomyelitis

Diagnosis

Signs and Symptoms

Symptoms:

• Back pain, usually insidious in onset but increasing with time
• Abdominal pain
• Loss of appetite
• Malaise
• Signs:
• Back stiffness
• Refusal to walk
• Pain on spinal percussion
• Loss of lordosis
• Fever: Usually low-grade, but may be absent

• Note the presence or absence of normal lumbar lordosis.
• Look for pain or refusal to bend forward.
• Look for pain on paraspinal percussion.
• Look for pain on abdominal palpation in lumbar discitis.
• Neurologic examination remains normal, except in late presentations of fulminant discitis.
• Tests
• Lab
• White blood cell count, ESR, and C-reactive protein usually are mildly elevated but may be normal.
• Obtain a blood culture even though it is positive <30% of the time.
• No specific laboratory tests exists for this disorder.
• Imaging
• Plain films are positive only after several weeks; they show irregularity and narrowing of the disc space, with mild osseous involvement.
• MRI:
• For suspected cases of discitis, shows the pathologic features before abnormalities are visible radiographically.
• Gives more detailed anatomic information than a bone scan, but a bone scan is an acceptable alternative
• Pathological Findings
• Chronic inflammation
• Destruction of disc structure and endplates
• Differential Diagnosis
• Tuberculosis (usually shows more destruction of adjacent bone)
• Vertebral osteomyelitis (more destruction of bone than disc, but these 2 entities may merge)
• Treatment
• General Measures
• Rest
• Immobilization
• Antibiotics
• For childhood spontaneous discitis, no biopsy or debridement is needed because treatment of staphylococcal infection is virtually always successful.
• This treatment should be given intravenously if the patient is severely ill, orally if the patient is only mildly symptomatic.
• Bed rest and bracing may be used if pain is pronounced.
• For discitis in the compromised host, biopsy and drainage should be performed.
• Special Therapy
• Physical Therapy
• Therapy is useful for adults with severe back stiffness after treatment has begun.
• Medication (Drugs)
• For routine spontaneous discitis, oxacillin, dicloxacillin, and cephalosporin are indicated.
• For complicated cases or in compromised hosts, broad-spectrum antibiotics effective against Gram-negative and anaerobic organisms should be added.
• NSAIDs or mild narcotics may help patients with severe pain initially until the infection is controlled.
• Surgery
• Biopsy may be required in the immunocompromised patient, or one for whom medical therapy has failed.
• Anterolateral or posterolateral approach with fluoroscopic guidance
• Drainage may be required for patients who fail to respond to medical management alone.
• Usually obtained via an anterior approach to allow adequate visualization, debridement, and safety
• Surgical reconstruction of the spine segment may be indicated for adults with substantial disc space destruction or endplate compromise.
• Follow-up
• Prognosis
• Prognosis is good once the infection has cleared.
• After childhood discitis, the vertebrae adjacent to the infected disc usually develop a spontaneous painless fusion.
• In adults, spontaneous fusion does not always occur, and back pain may persist.
• Complications
• Persistence of infection (lack of symptom improvement in 1-2 weeks) requires accurate identification of the organism and adequate debridement.
• Patient Monitoring
• Physical examination is the most useful means for monitoring infection healing.
• The examiner should check for tenderness to percussion and range of forward flexion.
• Radiographs and ESR lag far behind the clinical course.