Pott's Disease

Original Editors - David Pieschel & Craig Satterley from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Craig Satterley, Lucinda hampton, Admin, Elaine Lonnemann, David Pieschel, WikiSysop, Kim Jackson, Joao Costa, Sai Kripa, Mohit Chand, 127.0.0.1, Wendy Walker, Evan Thomas and Nupur Smit Shah

Introduction

Vertebrae - Tuberculosis. 1910 museum.

Tuberculous spondylitis, also known as Pott disease, refers to vertebral body osteomyelitis and intervertebral discitis from tuberculosis (TB). The spine is the most frequent location of musculoskeletal tuberculosis, and commonly related symptoms are back pain, kyphotic deformity of the spine, lower limb weakness, and paraplegia.

The disease has significantly increased in developed nations, particularly among the immunosuppressed population secondary to global migration and travel. There has been an ominous, increasing trend in the occurrence of multidrug-resistant bacterial strains of tuberculosis in developing nations over the past decades, a tough challenge to the global community. Accordingly, the disease continues to exist as a major global public health menace to date.

Epidemiolgy

Community health workers treating TB

Tuberculous spondylitis is one of the more common infections of the spine in countries where TB is prevalent. Unfortunately, the incidence of Pott Disease, as with other forms of TB, is on the rise, because of new multiple drug resistant strains.

• Discitis and/or osteomyelitis comprise approximately 50% of all musculoskeletal tuberculosis, and usually affects the lower thoracic and upper lumbar levels of the spine.
• The World Health Organisation (WHO) reported 10.4 million new cases of tuberculosis in 2016, with 46.5% of cases reported from the South East Asian Region alone. India contributed to 23% of the global TB burden.

Etiology

Pott's disease can develop when individuals inhale air containing the tuberculosis-causing bacteria Mycobacterium tuberculosis into their lungs. From the lungs, an infection can spread to the spine. The spread is hematogenous, i.e. transmitted through the blood. Bacteria reach the spine via the hematogenous route, from the lungs or lymph nodes. It spreads via the paravertebral plexus of veins, i.e. Batson's plexus. Someone with active TB infects the air with aerosol droplets by spitting, sneezing, coughing, speaking, etc. Each sneeze can release up to 40,000 aerosol droplets, and it only takes one infected droplet to spread TB.

Some known risk factors for TB include prolonged exposure to infected patients, immunodeficiencies (HIV, alcohol, drug abuse), overcrowding, malnutrition, poverty, and lower socio-economic situation.

Types of Vertebral Tuberculosis

Lesions in the vertebrae may be of the following types:

Paradiscal:

• This is the commonest type.
• The contiguous areas of two adjacent vertebrae along with the intervening disc are affected.

Central:

• The body of a single vertebra is affected.
• This leads to the early collapse of the weakened vertebra.
• The nearby disc may be normal.

Anterior:

• The infection has localized to the anterior part of the vertebral body.
• The infection spreads up and down under the anterior longitudinal ligament.

Posterior:

• The posterior complex of the vertebra, i.e., the pedicle, lamina, spinous process and transverse process, are affected

Characteristics/Clinical Presentation

TB, kyphosis spine

The clinical presentation of spinal tuberculosis is variable. The manifestations depend upon the duration of illness, severity of the disease, site of the lesion, and presence of associated complications, including deformity and neurological deficit.

1. In an uncomplicated disease, the patient typically presents with back pain. In tuberculosis, back pain might result from the active disease itself (caused by inflammation), bone destruction, and instability. Rest pain is pathognomonic, and rarely, radicular pain can be the main presenting symptom.
2. In complicated tubercular spine disease patient may present with deformity, instability, and neuro deficit.

Pott's Disease Cold Abscess

Constitutional symptoms, including weight or appetite loss, fever, and malaise/ fatigue, are less commonly associated with extrapulmonary tuberculosis than pulmonary disease.

• Cold Abscess: These abscesses typically lack all the inflammatory signs obvious in abscesses; and hence, the name.
• Deformity: Owing to the greater involvement of the anterior spinal column in TB, the spinal column progressively develops a kyphosis, especially in the thoracic and thoracolumbar spine.
• Neurological Deficit: Can occur either at the active stage of the disease (secondary to compression from an abscess, inflammatory tissue, sequestrum or spinal instability) or during the healed stage (usually secondary to mechanical traction spinal defect.
• Pediatric Spinal TB: Because of the immaturity and increased flexibility of the spine in children, they are prone to developing severe deformity progression. Children can also experience worsening deformity after the disease has completely healed, and they require follow-up until skeletal maturity..

Associated Co-morbidities

Estimated TB-related deaths among people living with HIV

Include: Immunosuppressive Disorders; HIV/AIDS; TB; Gastrectomy; Peptic Ulcer; Drug Addiction; Alcoholism; Malnourishment; Low Socioeconomic Status.

Diagnosis

For the detection of tuberculosis, the following diagnostic tests are preferable:

• Chest X-ray
• Sputum cultures (to look for the presence of bacteria)
• Blood culture
• Tissue biopsy (to check for the possibilities of cancer)
• Mantoux Tuberculin skin tests ( results are positive in 84-95% of the patients having Pott’s disease)
• CT scanning: provides much better bony detail of irregular lytic lesions, sclerosis, disk collapse, and disruption of bone circumference. Low contrast resolution provides a better assessment of soft tissue, particularly in epidural and paraspinal areas. CT scanning reveals early lesions and is more effective for defining the shape and calcification of soft tissue abscesses, which is common in TB lesions.
• MRI is the criterion gold standard for evaluating disk-space infection and osteomyelitis of the spine and is most effective for demonstrating the extension of disease into soft tissue and the spread of tuberculous debris under the anterior and posterior longitudinal ligaments.MRI is also called the most effective imaging study for demonstrating neural compression. MRI findings useful to differentiate tuberculosis spondylitis from pyogenic spondylitis include thin and smooth enhancement of the abscess wall and well-defined paraspinal abnormal signal, whereas thick and irregular enhancement of abscess wall and ill-defined paraspinal abnormal signal suggest pyogenic spondylitis. Thus, contrast-enhanced MRI appears to be important in the differentiation of these two types of spondylitis.
• Biopsy: Use of a percutaneous CT-guided needle biopsy of bone lesions can be used to obtain tissue samples. This is a safe procedure that also allows therapeutic drainage of large paraspinal abscesses.
• Polymerase Chain Reaction (PCR): PCR techniques amplify species-specific DNA sequences which is able to rapidly detect and diagnose several strains of mycobacterium without the need for prolonged culture. They have also been used to identify discrete genetic mutations in DNA sequences associated with drug resistance.

Medical Management

A combination of first-line drugs usually cures TB.

The mainstay of treatment in spinal TB is chemotherapy (antitubercular treatment). Tubercle bacilli may exist as intracellular or extracellular forms or as dormant or rapidly multiplying forms. Multi-drug treatment is essential to attack the bacilli in various stages or forms and reduce the instance of drug resistance.

It is essential to classify spinal TB disease into a complicated and uncomplicated disease based on their presentation.

1. Uncomplicated spinal TB is essentially a medical disease.
2. Complicated TB spine patients need surgical intervention in addition to chemotherapy.
   • The first line of treatment for Pott’s disease is the surgical removal of the tubercular infection. Before and after the surgery, doctors administer anti-tubercular medications. The surgical reconstruction of the spine follows this procedure.
   • The treatment protocol is formulated based on the presence or absence of neurological involvement. In the case of neurological involvement, doctors usually prefer pharmacotherapy over surgery. The anti-tubercular medications employed in the pharmacotherapy are Isoniazid, Rifampicin, Ethambutol, and Pyrazinamide.
   • Surgery done during the active course of the disease is much safer with a faster and better response.

Education

Patient education is extremely important in the management of TB at the level of an individual, as well as the entire community.

• The need for isolation of patients who can potentially transmit the disease is paramount.
• Strict compliance to long-term chemotherapy is essential for complete cure from the infection.
• Healthcare providers need to clearly communicate to the parents in pediatric disease the chances of deformity progressing even years after the infection has healed and the necessity of regular follow-up until skeletal maturity..

Physical Therapy Management

Patients with Pott's disease often undergo spinal fusion or spinal decompression surgeries to correct their structural deformity and prevent further neurological complications. There are no established guidelines which dictate treatments that will yield positive outcomes in such patients. However, treatment regimens should address each patient individually, focusing on any impairments, functional limitations and/or disabilities with which they present.

PT Management Post-Spinal Decompression Surgery

• Spinal Stabilization Exercises
• Maitland
• Back School
• Exercise and Strengthening

When compared with other physical therapy treatments and self-management, spinal stabilization exercises were found to produce significantly more positive ratings in global outcomes. Pain and disability, however, did not show significant improvement when compared to the other two treatment options.

PT Management Post-Spinal Fusion Surgery

• TENS (Transcutaneous Electrical Neuromuscular Stimulation)
• Aquatic Therapy
• Overground Training (Walking Program)
• Aerobic Exercise
• Trunk Strengthening

Studies examining the use of TENS have shown higher frequencies are more effective in decreasing neuropathic pain. Aerobic exercise, PT, and trunk strengthening interventions have all attained significant decreases in pain, psychological distress and disability.

Case Reports

Adegboye OA.Non-Hodgkin's lymphoma “masquerading” as Pott's disease in a 13-year old boy. Indian Journal of Medical and Paediatric Oncology. 2011 Apr-Jun; 32(2): 101–104.

A 13-year-old boy presenting with back inflammation, lower extremity paralysis, bowel and bladder incontinence, progressive weight loss, numbness below T10 and low grade fever.  Radiographs taken indicative of Pott's disease.

Lotfinia I, Vahedi P.Late-onset post-diskectomy tuberculosis at the same operated lumbar level: case report and review of literature. European Spine Journal. 2010 July; 19(Suppl 2): 226–232.

A 43 y/o male presents with chronic low back pain for 4 months with intermittent pus drainage from his scar status post lumbar discectomy 8 years previously. Patient reported no history of TB but he had worked as a secretary at a hospital for years.