eMedicine Specialties > Infectious Diseases > Bone and Joint Infections

Pott Disease (Tuberculous Spondylitis)

Author: Jose A Hidalgo, MD, Assistant Professor, Universidad de San Marcos Medical School; Attending Physician, Department of Internal Medicine, Division of Infectious Diseases, Guillermo Almenara Hospital
Coauthor(s): George Alangaden, MD, Staff Physician, Associate Professor, Department of Internal Medicine, Division of Infectious Diseases, Detroit Medical Center, Wayne State University School of Medicine
Contributor Information and Disclosures

Updated: Aug 29, 2008

Introduction

Background

Pott disease, also known as tuberculous spondylitis, is one of the oldest demonstrated diseases of humankind, having been documented in spinal remains from the Iron Age and in ancient mummies from Egypt and Peru.¹ In 1779, Percivall Pott, for whom Pott disease is named, presented the classic description of spinal tuberculosis.²

Since the advent of antituberculous drugs and improved public health measures, spinal tuberculosis has become rare in developed countries, although it is still a significant cause of disease in developing countries. Tuberculous involvement of the spine has the potential to cause serious morbidity, including permanent neurologic deficits and severe deformities. Medical treatment or combined medical and surgical strategies can control the disease in most patients.

Pathophysiology

Pott disease is usually secondary to an extraspinal source of infection. The basic lesion involved in Pott disease is a combination of osteomyelitis and arthritis that usually involves more than one vertebra. The anterior aspect of the vertebral body adjacent to the subchondral plate is area usually affected. Tuberculosis may spread from that area to adjacent intervertebral disks. In adults, disk disease is secondary to the spread of infection from the vertebral body. In children, because the disk is vascularized, it can be a primary site.³

Progressive bone destruction leads to vertebral collapse and kyphosis. The spinal canal can be narrowed by abscesses, granulation tissue, or direct dural invasion, leading to spinal cord compression and neurologic deficits. The kyphotic deformity is caused by collapse in the anterior spine. Lesions in the thoracic spine are more likely to lead to kyphosis than those in the lumbar spine. A cold abscess can occur if the infection extends to adjacent ligaments and soft tissues. Abscesses in the lumbar region may descend down the sheath of the psoas to the femoral trigone region and eventually erode into the skin.

Frequency

United States

• Although the incidence of tuberculosis increased in the late 1980s to early 1990s, the total number of cases has decreased in recent years.
• The frequency of extrapulmonary tuberculosis has remained stable.
• Bone and soft-tissue tuberculosis accounts for approximately 10% of extrapulmonary tuberculosis cases and between 1% and 2% of total cases.
• Tuberculous spondylitis is the most common manifestation of musculoskeletal tuberculosis, accounting for approximately 40-50% of cases.⁴

International

Approximately 1-2% of total tuberculosis cases are attributable to Pott disease.

In the Netherlands between 1993 and 2001, tuberculosis of the bone and joints accounted for 3.5% of all tuberculosis cases (0.2-1.1% in patients of European origin and 2.3-6.3% in patients of non-European origin).⁵

Mortality/Morbidity

• Pott disease is the most dangerous form of musculoskeletal tuberculosis because it can cause bone destruction, deformity, and paraplegia.
• Pott disease most commonly involves the thoracic and lumbosacral spine. However, published series have show some variation.^6,7,8,9 Lower thoracic vertebrae is the most common area of involvement (40-50%), followed closely by the lumbar spine (35-45%). In other series, proportions are similar but favor lumbar spine involvement.¹⁰
• Approximately 10% of Pott disease cases involve the cervical spine.

Race

• Data from Los Angeles and New York show that musculoskeletal tuberculosis primarily affects African Americans, Hispanic Americans, Asian Americans, and foreign-born individuals.
• As with other forms of tuberculosis, the frequency of Pott Disease is related to socioeconomic factors and historical exposure to the infection.

Sex

Although some series have found that Pott disease does not have a sexual predilection, the disease is more common in males (male-to-female ratio of 1.5-2:1).

Age

• In the United States and other developed countries, Pott disease occurs primarily in adults.
• In countries with higher rates of Pott disease, involvement in young adults and older children predominates.

Clinical

History

• The presentation of Pott disease depends on the following:
  • Stage of disease
  • Affected site
  • Presence of complications such as neurologic deficits, abscesses, or sinus tracts
• The reported average duration of symptoms at diagnosis is 4 months⁷ but can be considerably longer, even in most recent series.^11,9 This is due to the nonspecific presentation of chronic back pain.
• Back pain is the earliest and most common symptom.
  • Patients with Pott disease usually experience back pain for weeks before seeking treatment.
  • The pain caused by Pott disease can be spinal or radicular.
• Potential constitutional symptoms of Pott disease include fever and weight loss.
• Neurologic abnormalities occur in 50% of cases and can include spinal cord compression with paraplegia, paresis, impaired sensation, nerve root pain, and/or cauda equina syndrome.
• Cervical spine tuberculosis is a less common presentation but is potentially more serious because severe neurologic complications are more likely.
  • This condition is characterized by pain and stiffness.
  • Patients with lower cervical spine disease can present with dysphagia or stridor.
  • Symptoms can also include torticollis, hoarseness, and neurologic deficits.
• The clinical presentation of spinal tuberculosis in patients infected with the human immunodeficiency virus (HIV) is similar to that of patients who are HIV negative; however, spinal tuberculosis seems to be more common in persons infected with HIV.¹²

Physical

• The examination should include the following:
  • Careful assessment of spinal alignment
  • Inspection of skin, with attention to detection of sinuses
  • Abdominal evaluation for subcutaneous flank mass
  • Meticulous neurologic examination
• Although both the thoracic and lumbar spinal segments are nearly equally affected in persons with Pott disease, the thoracic spine is frequently reported as the most common site of involvement. Together, they comprise 80-90% of spinal tuberculosis sites. The remaining cases correspond to the cervical spine.
• Almost all patients with Pott disease have some degree of spine deformity (kyphosis).
• Large cold abscesses of paraspinal tissues or psoas muscle may protrude under the inguinal ligament and may erode into the perineum or gluteal area.
• Neurologic deficits may occur early in the course of Pott disease. Signs of such deficits depend on the level of spinal cord or nerve root compression.
• Pott disease that involves the upper cervical spine can cause rapidly progressive symptoms.
  • Retropharyngeal abscesses occur in almost all cases.
  • Neurologic manifestations occur early and range from a single nerve palsy to hemiparesis or quadriplegia.
• Many persons with Pott disease (62-90% of patients in reported series^6,7 ) have no evidence of extraspinal tuberculosis, further complicating a timely diagnosis.
• Information from imaging studies, microbiology, and anatomic pathology should help establish the diagnosis.

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