Erythrocyte Sedimentation Rate

The erythrocyte sedimentation rate is used both for evaluation and clinically monitor osteomyelitic disc space infection. Though it is found to be elevated in more than 70% of the children with vertebral infection, erythrocyte sedimentation rate only indicates an inflammatory process and is not diagnostic in itself.

The reading could be as high as >100 mm/h in some patients but in majority it is >50.

There are other instances when it can be found elevated. For example – Surgery.

When ESR is increased after surgery, it usually decreases to a nearly normal level at 4 weeks after surgery and persistent elevation beyond this period along with associated clinical findings, indicates a persistent infection.

C Reactive Protein

Elevation of C-reactive protein is an early indicator of infection and returns rapidly to normal with resolution of the infection. ESR takes much longer to return to normal. A raised CRP is again a non specific indicator of inflammation and its value should be

However longer time is required to obtain the results compared with the ESR.

Leukocyte Count [White Blood Cell Count]

Leukocytosis may be a feature in spinal infections but again it is not helpful in diagnosing spinal infection as  White blood cell counts may decrease in infants and debilitated patients.

Moreover, raised white blood cell counts may indicate areas of infection other than the spine.

Blood Culture

Blood cultures are helpful if positive. Positive blood culture results only when the blood sample is withdrawn at the time of acute febrile illness. A positive blood culture may be adequate for the diagnosis and treatment of osteomyelitis  but it rarely happens.

CD4 Counts

This is important in HIV positive patients.It has been reported that spinal infection occurred when the CD4 count was >200/mL, while osteoarticular and soft-tissue infection occur present when the CD4 count was <200/mL. Some authors have even suggested CD4 count as a predictor of the clinical course. Patients with  with a moderate decrease in the CD4 count (about 200/mL) whereas those with lower counts perform worse.