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Pediatric Discitis

- Discussion:
    - a benign, self-limiting inflammation or infection of an intervertebral disc space or a vertebral end-plate;
          - it may represent extension of subacute vertebral endplate osteomyelitis which does not produce a progressive vertebral osteomyelitis;
    - discitis presents in different ways at different ages;
          - in adult disc space usually goes on to fusion, where as in child disc space is usually restored;
          - can be difficult to diagnose in the uncommunicative child of one to three years of age;
    - prevalence:
         - occurs primarily in younger pts, & lumbar spine is most common location.
         - most commonly occurs between ages 4-10;
    - diff dx:
         - osteomyelitis of the spine:
         - post operative diskitis:
         - tuberculous spondylitis
    - outcomes:
         - in the report by Brown, et al. (2001), the authors followed 11 consecutive cases of discitis;
         - non-specific clinical features included refusal to walk (63%), back pain (27%), inability to flex the lower back (50%) and a loss of lumbar lordosis (40%);
         - laboratory tests were unhelpful and cultures of blood and disc tissue were negative.
         - MRI reduces the diagnostic delay and may help to avoid the requirement for a biopsy.
         - in 75% of cases it demonstrated a paravertebral inflammatory mass, which helped to determine duration of the oral therapy given after initial intravenous antibiotics;
         - at mean follow-up of 21 months (10 to 40), all the spines were mobile and the patients free from pain;
         - radiological fusion occurred in 20% and was predictable after two years;
         - at follow-up, MRI showed variable appearances: changes in the vertebral body usually resolved at 24 months and recovery of disc was seen after 34 months;
         - ref: Discitis in young children.  

- Exam:
    - unlike osteomyelitis, there are usually no systemic symptoms: (affected children are typically afebrile);
    - child typically complains of back pain and refuses to flex the spine;
          - pts may be able to flex trunk at hips, but will not flex spine;
    - young children may also complain of hip or abdominal pain and may refuse to stand or walk;
          - child may have a limp or may refuse to sit, stand, or walk.
    - tenderness over the spine, paravertebral muscle spasm, loss of normal lumbar lordosis, or limitation of spine motion/
          - localized tenderness in the lumbar region is a common finding.

- Labs:
    - WBC is usually normal;
    - ESR rate is usually elevated > 40;
    - CRP
    - when a causative organism can be identified, it is most commonly S. aureus.
         - biopsy is indicated only for children who fail to respond to non-operative management, and for older children & adolescents in 
                whom a different organism may be suspected or if TB or tumor is suspected;

- X-rays:
    - x-rays of spine may appear normal early on;
    - characteristic changes include disc-space narrowing or of irregularity involving adjacent vertebral end-plates;
         - over half pts progress to interbody fusion;

- Bone Scan:
    - technetium bone scan demonstrates increased uptake of isotope in infected disc space;
    - may be useful in early dx of discitis.

- CT scans & MRI:
    - MRI is more sensitive than technetium bone scans in early diskitis;
    - MRI will show decreased signal on T1 images and increased signal on T2;
    - references:
          - Magnetic resonance imaging of musculoskeletal infections
          -A comparison between magnetic resonance imaging and scintigraphic bone imaging in the diagnosis of disc space infection in an animal model.  

- Treatment:
    - all children are put to bedrest;
    - use of spinal immobilization with a cast or orthosis depends on severity of the symptoms;
    - most children are treated empirically with systemic antibiotics;
          - since vascular acces to the disc is more abundant in children, antibiotics are usually successful;
          - child is put on a penicillinase resistant synthetic penicillin or cephalothin, even if the cultures are not positive;
    - some argue that antibiotics are only indicated when symptomatic treatment, such as immobilization, has failed

Discitis in childhood. 12-35-year follow-up of 35 patients.

Intervertebral disc space inflammation in children.   

Intervertebral discitis in children and adolescents.  

Lymph and blood supply of the human intervertebral disc. Cadaver study of correlations to discitis.

The penetration of antibiotics into the normal intervertebral disc.

Diskitis in children.

The spectrum of intervertebral disc-space infection in children.

Remodeling of the spine in spondylodiscitis of children at the age of 3 years or younger