Correspondence

A Pain in the Back

N Engl J Med 2001; 344:456-457February 8, 2001

Article

To the Editor:

In the Clinical Problem-Solving article by Lurie et al. (Sept. 7 issue),1 the authors describe an 80-year-old man with unexplained back pain, an elevated erythrocyte sedimentation rate, plain films that showed only degenerative changes, and normal findings on neurologic evaluation. I believe magnetic resonance imaging (MRI) with gadolinium should have been performed before computed tomographic (CT) myelography was performed. CT myelography is invasive and expensive, and it does not provide nearly the range of diagnostic information provided by MRI. As the discussant stated, the differential diagnosis in this case included chronic infection, a metastatic tumor, vasculitis, and multiple myeloma. MRI with gadolinium could have led to the diagnosis of all these conditions except vasculitis, whereas CT myelography would not have been diagnostic of these disorders.

John H. Rees, M.D.
Washington Hospital Center, Washington, DC 20010-2975

1 References

1. 1

   Lurie JD, Gerber PD, Sox HC. A pain in the back. N Engl J Med 2000;343:723-726
   Full Text | Web of Science | Medline

To the Editor:

We were surprised that Lurie et al. failed to mention spinal tuberculosis as a possibility in the 80-year-old man with midthoracic and lumbar back pain. In cases of Pott's disease, systemic symptoms are often absent, and diagnostic evaluations are often not undertaken until the process is advanced.1 Back pain or stiffness may be the only early symptom, with initially normal findings on spinal radiographs. Paravertebral soft-tissue abscesses, which develop in more than 50 percent of patients with spinal tuberculosis, could have accounted for the initial paraspinal tenderness in this patient.2 Finally, the earliest focus of disease in spinal tuberculosis is the anterior superior or inferior angles of the vertebral bodies — precisely the locations of bony loss seen on repeated radiographs obtained at a later date in this case.3 The lower thoracic and lumbar vertebrae are the most common sites of involvement.

Vincent Lo Re, III, M.D.
Todd Barton, M.D.
Shoshana Feiner, M.D.
Hospital of the University of Pennsylvania, Philadelphia, PA 19104

3 References

1. 1

   Hopewell PC. Overview of clinical tuberculosis. In: Bloom BR, ed. Tuberculosis: pathogenesis, protection, and control. Washington, D.C.: American Society for Microbiology, 1994:25-46.
   

2. 2

   Weaver P, Lifeso RM. The radiological diagnosis of tuberculosis of the adult spine. Skeletal Radiol 1984;12:178-186
   CrossRef | Web of Science | Medline

3. 3

   Yao DC, Sartoris DJ. Musculoskeletal tuberculosis. Radiol Clin North Am 1995;33:679-689
   Web of Science | Medline

To the Editor:

Expanding aortic aneurysm, epidural abscess, and vertebral compression fractures are common causes of nonmechanical back pain with acute onset.1 We are surprised that a CT scan of the thorax and abdomen was not part of the initial workup. Given the seriousness (and likelihood) of aortic disease in an 80-year-old man, this diagnosis warranted consideration early in the discussion.

Parameswaran Hari, M.D.
Ajay Joshi, M.D.
Gopal Krishna P. Chemiti, M.D.
Lankenau Hospital, Wynnewood, PA 19096

1 References

1. 1

   Borenstein DG. Chronic low back pain. Rheum Dis Clin North Am 1996;22:439-456
   CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Dr. Rees suggests that the patient should have undergone MRI with gadolinium rather than CT myelography. We agree that MRI is the preferred test when spinal infection1 or tumors are part of the differential diagnosis, but we believe that CT was a reasonable choice, given the principal diagnoses that the treating physicians were considering. They obtained a CT myelogram because of a presumptive diagnosis of spinal stenosis. CT and MRI appear to be equally useful for diagnosing spinal stenosis. The choice between them depends on factors such as cost, availability, reimbursement, the radiologist's skill, and the patient's safety.2 The treating physicians did not pursue the diagnosis of spinal infection, either because they simply did not consider it as a possibility or because they misinterpreted the absence of fever and of an elevated white-cell count as strong evidence against the diagnosis and failed to verify that the presumed diagnosis of spinal stenosis accounted for the main findings, including the very high erythrocyte sedimentation rate.

Lo Re and colleagues correctly point out that spinal tuberculosis was a possible diagnosis. The discussant, but not the treating physicians, strongly considered the possibility of spinal infection. When spinal infection is considered, clinical and epidemiologic features can help point to one of the specific etiologic agents, such as typical pyogenic bacteria, Mycobacterium tuberculosis, brucella, or fungi.3

Hari and colleagues note other disorders to be considered in developing a complete differential diagnosis for acute low back pain. In addition to tumors, compression fractures, and spinal infection, expanding aortic aneurysm, aortic dissection, pancreatitis, penetrating duodenal ulcer, pyelonephritis, prostatitis, nephrolithiasis, and metabolic bone disease are all possible diagnoses in a man with back pain that is not mechanical in nature.4

Jon. D. Lurie, M.D.
Paul D. Gerber, M.D.
Harold C. Sox, M.D.
Dartmouth Medical School, Hanover, NH 03756

4 References

1. 1

   Carragee EJ. Pyogenic vertebral osteomyelitis. J Bone Joint Surg Am 1997;79:874-880
   CrossRef | Web of Science | Medline

2. 2

   Kent DL, Haynor DR, Larson EB, Deyo RA. Diagnosis of lumbar spinal stenosis in adults: a metaanalysis of the accuracy of CT, MR, and myelography. AJR Am J Roentgenol 1992;158:1135-1144
   Web of Science | Medline

3. 3

   Colmenero JD, Jimenez-Mejias ME, Sanchez-Lora FJ, et al. Pyogenic, tuberculous, and brucellar vertebral osteomyelitis: a descriptive and comparative study of 219 cases. Ann Rheum Dis 1997;56:709-715
   CrossRef | Web of Science | Medline

4. 4

   Mazanec DJ. Low back pain syndromes: In: Black ER, Bordley DR, Tape TG, Panzer RJ, eds. Diagnostic strategies for common medical problems. Philadelphia: American College of Physicians, 1999:401-18.