Woman With Low Back Pain
Article Outline
A 53-year-old woman, with no pertinent medical history, presented to the emergency department, complaining of severe low back pain, general malaise, and bilateral thigh weakness for 2 days. She reported intermittent episodes of fever and progressively worsening low back pain during 3 weeks. Physical examination revealed lumbar and sacral tenderness. Laboratory evaluation revealed that the WBC count was 19,100 cells/mm3, segmented neutrophils 96%, and the C-reactive protein 23.3 mg/dL (normal <0.4 mg/dL). An abdominal radiograph (Figure 1) was obtained.
Figure 1.
The abdominal radiograph presenting free gas bubbles in the soft tissue over the paravertebral and retroperitoneal regions (arrows), with discal degeneration and space narrowing at the lumbar to sacral vertebrae.
Diagnosis
Pyogenic vertebral osteomyelitis with bilateral paravertebral abscesses
Computed tomographic (CT) scan of the abdomen and pelvis is shown in Figure 2. It displays multifoci of air bubbles in back muscles beside the vertebra. On the patient's admission, the abscesses were drained percutaneously, and culture revealed Escherichia coli. We treated with ceftriaxone for 6 weeks. Acid-fast stain results were negative. The patient was discharged in stable condition.
Figure 2.
CT scan of the abdomen and pelvis, with oral and intravenous contrast showing multifoci of air bubbles in back muscles beside the vertebra (arrows). Used with permission of Yu-Tse Tsan, MD, Department of Emergency Medicine, Taichung Veterans General Hospital, Taiwan, Republic of China.
A high index of suspicion is necessary in detecting pyogenic vertebral osteomyelitis because delays in diagnosis are common. Contiguous spread of infection can lead to paravertebral, subdural, retroperitoneal, or psoas abscesses.1 The major clinical manifestation is back pain, but fever is inconsistent. C-reactive protein is increased in 90% or more of patients.2 Radiographs will reveal the degree of bony destruction, and an early change can be disc space narrowing in nearly 75% of patients. Soft tissue extension must be suspected in the presence of an abnormal psoas shadow, widening of the mediastinum, or enlargement of the retropharyngeal soft tissue window. CT is the preferred imaging modality, given the high sensitivity and rapidity. CT provides detail of bony anatomy and also can identify the presence of adjacent soft tissue masses or abscesses.3 Magnetic resonance imaging is the most sensitive radiologic technique. Sensitivity, specificity, and accuracy are reported as 96%, 92%, and 94%, respectively.4 CT-guided needle biopsy is generally necessary to confirm the suspicion. Treatment is with surgical drainage and empiric antibiotics according to the probable origin of infection.5
References
- Pyogenic vertebral osteomyelitis presenting as exudative pleural effusion: a series of five cases. Chest. 1998;114:642–647
- . Pyogenic vertebral osteomyelitis. J Bone Joint Surg Am. 1997;79:874–880
- . Spinal infections: diagnostic tests and imaging studies. Clin Orthop Relat Res. 2006;444:27–33
- Vertebral osteomyelitis: assessment using MR. Radiology. 1985;157:157–166
- Single-stage treatment of pyogenic spinal infection with titanium mesh cages. J Spinal Disord Tech. 2006;19:376–382
For the diagnosis and teaching points, see page 294.
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PII: S0196-0644(08)00837-8
doi:10.1016/j.annemergmed.2008.05.022
© 2008 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
