History
Unfortunately, adult diskitis (discitis) has a slow, insidious onset, which can cause diagnosis to be delayed for months. Neck or back pain with localized tenderness is the initial presenting complaint. Movement exacerbates these symptoms, which are not alleviated with conservative treatment (eg, analgesics or bed rest).
In patients who are chronically ill, a high incidence of epidural extension of the infection exists, causing lower-extremity weakness or plegia. Fever, chills, weight loss, and symptoms of systemic disease may be present, but they are not common.
In postoperative patients, symptoms usually begin days to weeks after surgery. Symptoms are similar to those experienced by patients with spontaneous diskitis, consisting of pain without neurologic abnormality. Limited movement and localized tenderness also occur; however, superficial signs of infection are rare (only 10% of cases). Diagnosis is rarely delayed in postoperative patients, which is the main reason that neurologic deficit is uncommon in these cases.
The disease has a more acute course in children. A sudden onset of back pain, refusal to walk, and irritability are the most common symptoms. Fever is often present, accompanied by local tenderness and limited back motion.
Physical Examination
Localized tenderness over the involved area with concomitant paraspinal muscle spasm is the most common physical sign. If the cervical or lumbar segments are involved, restricted mobility secondary to pain occurs. Reported rates of neurologic deficit (eg, radiculopathy, myelopathy) vary widely, ranging from 2% to 70%. Cervical disease is associated with a much higher rate of neurologic deficit.
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Axial CT scan in a patient with diskitis demonstrates extensive destruction of the vertebral endplate. Note the preservation of the posterior elements, including facet joints, lamina, and spinous process. This is characteristic for pyogenic diskitis and less common in tuberculosis (Pott disease).
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Sagittal T1-weighted MRI of the lumbar spine in a 74-year-old man, revealing diskitis of the L4-L5 disk space. Note extensive destruction of the endplates of the adjacent vertebral bodies. No compression of the thecal sac is present, which is an important consideration when contemplating surgical intervention.
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Contrast-enhanced sagittal T1-weighted MRI image in a 55-year-old woman shows thoracic diskitis with an associated epidural abscess and spinal cord compression. Because of the significant cord compression, this patient underwent surgical decompression.
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Trajectory of a needle in a biopsy of the infected disk space guided by CT scan. Care is taken to avoid the thecal sac and nerve roots.
