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Transcript of Pott Disease
- Potts sPine Moderator: Dr peeyush sharma Presenter: Dr Pramod mahender
- Potts disease This entity was first described by Percivall Pott. He noted this as a painful kyphotic deformity of the spine associated with paraplegia. Tuberculosis of the spine is one of the oldest diseases afflicting humans. Evidences of spinal tuberculosis have been found in Egyptian mummies dating back to 3400 BC
- One fifth of TB population is in India. Three percent are suffering from skeletal TB, 50% of these suffer from spinal lesion and almost 50% are from pediatric group. An estimated 2 million or more patients have active spinal tuberculosis. Every day 1000 die of tuberculosis in India.
- Regional Distribution 1 Cervical 12% 2 cervicodorsal 5% 3 Dorsal 42% 4 Dorsolumbar 12% 5 Lumbar 26% 6 Lumbosacral 3%
- Pathophysiology Pott disease is usually secondary to an extraspinal source of infection. The basic lesion is a combination of osteomyelitis and arthritis. The area usually affected is the anterior aspect of the vertebral body adjacent to the subchondral plate. 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.
- Progressive bone destruction leads to vertebral collapse and kyphosis. The spinal canal can be narrowed by abscesses, granulation tissue, or direct dural invasion. This leads to spinal cord compression and neurologic deficits. Kyphotic deformity occurs as a consequence of collapse in the anterior spine. Lesions in the thoracic spine have a greater tendency for kyphosis than those in the lumbar spine. The collapse is minimal in cervical spine because most of the body weight is borne through the articular processes. Healing takes place by gradual fibrosis and calcification of the granulmatous tuberculous tissue. Eventually the fibrous tissue is ossified, with resulting bony ankylosis of the collapsed vertebrae.
- Paravertebral abscess formation occurs in almost every case. With collapse of the vertebral body, tuberculous granulation tissue, caseous matter, and necrotic bone and bone marrow are extruded through the bony cortex and accumulate beneath the anterior longitudinal ligament. These cold abscesses gravitate along the fascial planes and present externally at some distance from the site of the original lesion. In the lumbar region the abscess gravitates along the psoas fascial sheath and usually points into the groin just below the inguinal ligament. In the thoracic region, the longitudinal ligaments limit the abscess, which is seen in the radiogram as a fusiform radiopaque shadow at or just below the level of the involved vertebra. Thoracic abscess may reach the anterior chest wall in the parasternal area by tracking via the intercostal vessels.
- The lesion could be: Florid - invasive and destructive lesion. Non destructive - lesion suspected clinically but identifiable by modern investigations like CT scan or M.R.I. Encysted disease Carries sicca Hypertrophied Periosteal lesion.
- Recently, two distinct patterns of spinal TB can be identified, the classic form, called spondylodiscitis (SPD) a atypical form characterized by spondylitis without disk involvement (SPwD). SPwD seems to be the most common pattern of spinal TB.
- Anatomically the lesion could be 1. Paradiscal - destruction of adjacent end plates and diminution of disc space. 2. Appendeceal (Posterior) - involvement of pedicles, laminae, spinous process. 3. Central - Cystic or lytic, concertina collapse. 4. Anterior longitudinal lig, Aneurysmal phenomenon 5. Synovitis in post facet
- History Presentation depends on the following: Stage of disease Site Presence of complications such as neurologic deficits, abscesses, or sinus tracts The reported average duration of symptoms at the time of diagnosis is 3-4 months. Back pain is the earliest and most common symptom. Patients have usually had back pain for weeks prior to presentation. Pain can be spinal or radicular. Constitutional symptoms 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, or cauda equina syndrome. Cervical spine tuberculosis is a less common presentation 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, the relative proportion of individuals who are HIV positive seems to be higher.
- Natural course of disease 53% died within 10 yrs of onset Early stage of healing focus surrounded by sclerotic bone Ivory vertebra Early radiological sign of healing sharpening of fuzzy paradiscal margins & reappearance and minrralization of tuberculae Several vertebrae destroyed fibrous tissue Disc space destroyed bony ankylosis/bone block formation
- Lab Studies Tuberculin skin test (purified protein derivative [PPD]) demonstrates a positive finding in 84-95% of patients who are nonHIV-positive. Erythrocyte sedimentation rate (ESR) may be markedly elevated . The enzyme-linked immunosorbent assay (ELISA) has a reported sensitivity of 60 to 80 per cent The polymerase chain reaction A brucella complement fixation test
- IFN- Release Assays (IGRAs) Recently, two in vitro assays that measure T cell release of IFN- in response to stimulation with the highly tuberculosis- specific antigens ESAT-6 and CFP-10 have become commercially available.
- Microbiology studies to confirm diagnosis: Obtain bone tissue or abscess samples to stain for acid-fast bacilli (AFB), and isolate organisms for culture and susceptibility. CT-guided procedures can be used to guide percutaneous sampling of affected bone or soft tissue structures. These study findings may be positive in only about 50% of the cases.
- X Ray appearances Lytic destruction of anterior portion of vertebral body Increased anterior wedging Collapse of vertebral body Reactive sclerosis on a progressive lytic process Enlarged psoas shadow with or without calcification Vertebral end plates are osteoporotic. Intervertebral disks may be shrunk or destroyed. Vertebral bodies show variable degrees of destruction. Fusiform paravertebral shadows suggest abscess formation. Bone lesions may occur at more than one level.
- X Ray appearances Discovertebral lesions, detected in 93% of patients, Localized fluffy osseous destruction with surrounding osteoporosis is the earliest signs. concentric collapse and may look like A.V.N. Local lytic lesion may cause problem of diagnosis from neoplasic lesion. destruction of adjacent vertebrae, Konstram (K) angle appears and shows the progress on follow up. Skipped lesion (10% cases) can be diagnosed on suspicion and in correct size film.
- X-ray of the thoracolumbar spine (Lateral view) showing wedge collapse of L1 and L2 vertebral bodies.
- X-ray of the spine in a child showing complete destruction of D12 and L1 vertebral bodies leaving only the pedicles.
- Kumars clinico-radiological Classification stage features Usual duration I Pre- Straightening, spasm, 3 verte K:>60 >2 years
- CT scanning 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. It detects early lesions and is more effective for defining the shape and calcification of soft tissue abscesses