27 May Discitis in Children
Discitis is a condition characterized by the inflammation of the intervertebral disc. It can be caused by a surgical or diagnostic procedure or spontaneously. It can be a direct pathogenic invasion (procedurally) or a hematogenous spread. Ear infections and skin infections are two common sources of pathogenic spread to the blood which can then infect the discs. As the intervertebral discs are avascular, they must get their nutrition and blood supply via diffusion through the vertebral endplates. This makes it hard for them to ward off infection and lead to debilitating sequelae.
The most common symptom of discitis is severe back pain, which may or may not be associated with fever. The back pain is more generalized (poorly localized) as compared to radiculopathic pain which is localized. In children, it is suspected when they are unable to walk or stand up as that is extremely painful to do so. It affects the gait and posture as some children try to adjust their posture to avoid pain.
Diagnosing discitis can be difficult as the symptoms are vague, the blood work can often be equivocal (but there is often a high white blood cell count, and they may have a higher erythrocyte sedimentation rate). A plain x-ray will detect loss of normal disc height, show shrinkage of a disc’s size or shape, and may reflect erosion of the vertebral bodies’ endplates, both of which are signs of discitis. A disc biopsy is not needed to diagnose children with discitis. Magnetic resonance imaging (MRI) can be very a useful imaging tool that can visualize the spine’s soft and hard tissues in great detail, which helps in evaluating for the extent of the disease.
In children, prolonged discitis can lead to autofusion, which is basically scar tissue taking over the disc tissue itself, which then fuses the bones together rendering them immobile. A spinal brace is recommended for a child with discitis, which immobilizes the area and actually helps the vertebrae fuse in a well-aligned, pain-free position. Patients with an active infection (with leukocytosis) may require intravenous antibiotics that cover Staphylococcus aureus (implicated in 60% of all cases). Antibiotics usage has been found to be associated with earlier response and fewer relapses. Other steps of management include bed rest, analgesia and immobilization by casting, may help with pain control. The prognosis is usually good but there may be residual anomalies of the disc space and adjacent vertebrae as found on long-term follow-up.
Overall, it is important to keep discitis in mind when dealing with a child that suffers from back pain, limited spinal mobility, and unexplained irritability. Once the more common reasons for this presentation are excluded, an MRI should be considered to make the diagnosis. The goal of management is to diagnose early enough to begin management aimed at reducing the risk of bone lesions requiring surgical interventions and/or the development of permanent alteration of spine mobility.