Pott Disease or Potts Disease (Spinal TB, or TB Spine) is the commonest form of joint and bone tuberculosis in West Africa and children and old age is a risk factor to having TB Spine (that is, extremes of ages predispose to having tuberculosis of the spine). TB spine is a form of Tuberculosis that affects the spinal bones and may lead to paralysis of chronic back pain. Percival Pott was the one who gave the first complete report of tuberculosis of the spine, hence the name Potts Disease.
Potts Disease Causes (Etiology)
- Mycobacterium tuberculosis is the most common cause of TB spine
- Mycobacterium bovis is another cause of TB Spine
- Mycobacterium Avium Intracellulare Scrofulaceum Complex (MAIS complex) an atypical form of mycobacterial infection
- Other atypical forms of mycobacteria such as Skotochromagens, photochromagens and Rapidly growing Mycobacteria
Potts Disease Epidemiology
Tuberculosis of the spine is the most common infective cause of back pain worldwide and one of the most common causes of back pain in the young and young adults. Potts disease occurs at the most dangerous site of skeletal TB which can cause severe complications when not treated promptly. There are more than 2million active cases of TB Spine cases today.
Potts Disease Pathophysiology
Potts Disease is a blood borne infection Blood borne infection that usually spreads from another focus such as from pulmonary tuberculosis or abdominal tuberculosis either through the arterial blood or venous blood via the Batson venous plexus. The TB infection commences in the vertebral body and spreads to the disc and adjacent vertebrae. Most infections of the spine affect the vertebral bodies which then collapse into each other forming a kyphos or gibbus with caseation and cold abscess formation escaping into surrounding soft tissue.
As healing occurs following the infection, the vertebrae recalcify and bony fusion may occur between them and when forward angulation is much the spine is unsound and flares are common. Kyphosis may progress also.
The commonest sites of Potts Disease are the lower thoracic, lower cervical and lower lumbar regions i.e. near the junctions of the more mobile and less mobile segments of the spine.
Potts Disease Classification
- Early onset TB Spine: presents with pressure caused by an containing caseous material and bony sequestrum
- Late onset TB Spine: in this, there is increasing deformity of the spine with reactivation of old TB and it causes vascular insufficiency of the spinal cord
Potts Disease Risk factors
- Pulmonary Tuberculosis
- Untreated Tuberculosis
- Abdominal Tuberculosis
- Immune suppression such as in HIV/Aids
- Consumption of unpasteurized milk
Potts disease symptoms and Signs
TB Spine symptoms are like any other form of Tuberculosis.
- Weight loss and signs of malnutrition such as it occurs in Kwashiorkor and Marasmus especially in children
- Drenching Night sweats
- Fever especially in the evening
- Night cries for children and increased back pain in adults that wakes them up at night due to relaxation of muscles at night with loss of protection of the inflamed spine following muscle relaxation.
- Stiffness of the back with localized tenderness is an early sign or symptom of Potts Disease. Applying a force on the head on the erect spine in tuberculosis of the spine may elicit local pain in the spinal column.
- There may be presence of deformity of the spine in most cases of TB Spine such as spinal deformity may be a torticollis, or gibbus of kyphus or reversion of lumbar lordosis of the spine.
- Inability to bend forwards (that is, the forward flexion of the spine is limited when there is active Potts disease).
- Coin test: in this test, the patient always bends his hips and knees to pick objects from the floor instead of bending the back because of deformity and pain
Pott Disease Diagnosis and Laboratory results
- CT scan and MRI are more useful in visualizing cord compression.
- Mantoux test (Tuberculin skin test) will be greater than 10mm
- Needle biopsy of the bone affected for histology: this will show caseous necrosis and giant cell granuloma.
- Full blood count (FBC) will show lymphocytosis with normal or low packed cell volume (PCV)
- Erythrocyte Sedimentation Rate (ESR) is markedly raised
- X ray of the entire spine as there may be multiple segments of the spine affected
Potts disease X ray Features
- Early X ray findings of TB Spine include: osteoporosis of 2 adjacent vertebrae, narrowing of the disc spaces and Fuzziness of the end-plate
- Late X Ray findings in Tuberculosis of the spine include: Vertebral collapse such as wedge collapse or vertebra plana and Paraspinal soft tissue swelling
Potts Disease Treatment Guidelines and Physiotherapy
The aim of treatment in Tuberculosis of the spine is to eradicate or arrest the disease, prevent complications, correct deformity and prevent or treat paraplegia.
Treatment Modalities in TB Spine
There are about 3 treatment modalities in the management of TB Spine
Ambulant chemotherapy in TB Spine
This involves a combination of bacteriocidal and bacteriostatic drugs used for prolonged periods to treat TB Spine infection; it is usually done in early or limited Potts disease with no abscess formation. The treatment is for up to 1 year (2-3 months intensive phase) until X-ray shows resolution of bone changes.
Continuous bed rest and chemotherapy in TB Spine
This is done in advanced cases of Potts disease and in settings where Surgical skill is unavailable or when technical problems are too daunting.
Operative treatment of Potts Disease
This is indicated when abscesses can readily be drained in advanced disease with marked bone destruction and threatened or severe kyphosis with paraparesis. It involves drainage of abscesses, debridement, anterior decompression and grafting with post-operative orthotic support.
Atypical tuberculosis of the spine requires much more aggressive and prolonged treatment and Surgery is an early consideration. Others include taking care of the paraplegic patient such as skin care, bowel care, bladder care, deep venous thrombosis (DVT) prophylaxis, Maintenance of morale and Physiotherapy
Potts disease Complications
- Spinal cord damage
- Chronic back pain
- Secondary amyloidosis
- Concomitant involvement of the lung and rarely genito – urinary involvement.
- Deformity (hunchback Kyphosis)
Causes of spinal cord damage in TB Spine
- Spinal cord damage may occur following compression due to the following: Sequestra formation, Fluid pus accumulation, Prolapsed disc or Granulation tissue formation
- Spinal cord injury may also occur due to non-compressive causes such as Pachymeningitis or Thrombosis of spinal arteries
Potts disease Prevention
- Prompt treatment of pulmonary tuberculosis or any form of tuberculosis
- Ensure proper and complete treatment of any form of tuberculosis such as completing the required treatment course
- Avoid overcrowding
- Ensure proper ventilation of rooms and workplace
- Avoid contact with chronically coughing individuals
TB Spine or Tuberculosis of the spine (or Potts disease) is a devastating infection to the human spine which when not treated has a natural history that leads to paralysis, genitourinary sphincteric incontinence and their sequelae and the treatment is best conservative with similar outcome to operative treatment.