Pott's disease- tuberculosis of the spine

Presentation on Pott's disease- tuberculosis of the spine, cold abscess, Pott's paraplegia

1. Pott’s Disease Roll no 0954

2. The spine is the most common site of skeletal tuberculosis 50 per cent of all musculoskeletal TB. approximately 2 million people with spinal tuberculosis worldwide .

3. Artery of Adamkiewicz When damaged or obstructed, it can result in anterior spinal artery syndrome with loss of urinary and fecal continence and impaired motor function of the legs; sensory function is often preserved to a degree. largest anterior segmental medullary artery arises from a left posterior intercostal artery, which branches from the aorta, and supplies the lower two thirds of the spinal cord via the anterior spinal artery

4. Lower thoracic and lumbar vertebra- 80% Large amount of spongy tissue within vertebral body Degree of weight bearing which is comparatively more More vertebral mobility Proximity of maximum no of abdominal lymph nodes to this region

5. Cervical 12% Cervicodorsal 5% Dorsal 42% Dorsolumbar 12% Lumbar 26% Lumbosacral 3%

6. Sites within vertebra Central (<5%) less common Infection comes through nutrient A of vertebra Starts as diffuse osteomyelitis in middle of body Early collapse Central or concertina collapse of vertebra

7. 2 . Metaphyseal / intervertebral / paradiscal space(98%) Lower half of 1 vertebra and upper half of adjacent vertebra with intervening disc develop from one sclerotome Bacillaemia involves this embryological section more often Starts near epiphysis

8. 3. Anterior/ periosteal Primary focus- in front of body beneath ALL Via- branches of intercostal / lumbar As May give rise to anterior wedge compression 4. Appendiceal Transverse process and rarely vertebral arch 5. True tubercular arthritis Atlantoaxial and atlanto -occipital joints

9. Aetiopathogenesis Mycobacterium tuberculosis Always secondary Routes of infection Blood borne- commonest Lymph borne -from abdominal glands and lymph vessels

10. Pathology Blood-borne infection usually settles in a vertebral body adjacent to the intervertebral disc. Bone destruction and caseation follow, with infection spreading to the disc space and the adjacent vertebrae Tuberculous endarteritis which develops results in marrow devitalisation Tubercular follicle develops later Primary foci in lungs, lymph nodes or abdomen Bacillaemia Batson plexus spine

11. Lamellae are destroyed due to hyperemia causing osteoporosis So vertebral body gets easily compressed In thoracic vertebra because of normal kyphotic curve- anterior wedge compression more common cervical and lumbar-minimal wedging

12. Types of vertebral reactions Exudative Common severe osteoporosis Rapid spread Abcess is formed frequently Constitutional symptoms pronounced Caseative Rarer Mechanism of formation and spread of destruction is similar but slower

13. Cold abcess Non- pyogenic infection When body of vertebra collapses-> expresses a collection of caseous material, granulation tissue, tubercle bacilli, bone marrow, serum, wbcs Not associated with usual signs of inflammation It penetrates epiphyseal cortex and involves adjacent disc and vertebra

14. Beneath Ant longitudinal ligament- reaches neighbouring vertebra May penetrate Ant longitudinal ligament and migrate along lines of least resistance ( fascial planes, blood vessels, nerves) Posterior spread- pressure on spinal cord( more in thoracic) Post longitudinal ligament- limits spread of sequestra and bone fragments into joints

15. Spread of cold abcess Cervical region Behind prevertebral fascia Retropharyngeal space Post edge of SCM – axilla , arm Mediastinum , from here it may gravitate to -trachea - oesophagus -pleural cavity

16. Thoracic region May press spinal cord posteriorly causing paraplegia Laterally towards extrapleural space-effusion May penetrate ALL and lie in mediastinum May remain prevertebral and from here it may spread

17. Lateral arcuate ligament and quadratus lumborum Remains behind kidney/ extends along nerves related to bed of kidney Along 12 th , ilioinguinal and iliohypogastric nerves Presents on anterior abdominal wall Medial arcuate ligament enters psoas sheath Reaches lesser trochanter where psoas gets inserted Median arcuate ligament Lumbar abcess Branches of aorta

18. Lumbar region May remain paravertebral Psoas abcess Iliac crest Along femoral vessels to femoral triangle Along gluteal vessels to gluteal region Ischiorectal abcess -internal pudendal A Rarely to iliac crest May present in Petit’s triangle

19. Psoas sheath Fascia covering the psoas muscle Attaches to lumbar vertebrae and pelvic brim Thickened superiorly to form the medial arcuate ligament—a site of origin of the muscle of the diaphragm Psoas abcess - mimics femoral hernia, may reach iliac fossa , lumbar region , popliteal fossa

20. Three layers of fascia run outwards from the vertebrae, and fuse, enclosing muscles as they do so, to form the lumbar aponeurosis . The most posterior of these three fasciae, called the vertebral aponeurosis , extends outwards from the spines of the vertebrae to meet the middle layer, which arises from the tips of the transverse processes of the lumbar vertebrae, enclosing the erector spinae between them. The anterior layer arises from the junctions of transverse processes and bodies, and extends outwards to meet the middle layer, enclosing the quadratus lumborum , and separating it anteriorly from the psoas (see Fig. 19). The psoas fascia, or sheath, forms a fourth layer, which, rising from the front of the bodies of the lumbar vertebra (with arches to permit of the passing of the lumbar arteries), runs outwards and fuses with the anterior layer, shortly before it fuses with the middle and posterior layers to form the lumbar aponeurosis . Above, the psoas sheath commences at the internal arcuate ligament of the diaphragm, being derived from the diaphragmatic portion of the transversalis fascia, and thus the psoas muscle only receives its sheath after perforating the diaphragm. The lumbar aponeurosis is a narrow ligamentous band, extending from the last rib to the iliac crest. Besides giving attachments to the internal oblique and transversalis muscles, it is continuous by its anterior edge with the transversalis fascia, and hence it connects the outer border of the psoas sheath with the inner border of the transversalis fascia. It is pierced near the rib by the last intercostal artery and nerve, and near the ilium by the ilio-hypogastric nerve and accompanying artery. The fasciae lining the abdominal cavity in the lumbar region are the transversalis , lining the antero -lateral portion, the anterior layer of lumbar fascia, and psoas sheath completing the investment. The three layers forming the lumbar aponeurosis are, like it, inserted below into the crest of the ilium , the lower margin of the anterior layer being thickened to form the Mo-lumbar ligament, which extends from the transverse process of the last lumbar vertebra to the inner lip of the iliac crest (while its upper margin forms the external arcuate ligament). The psoas sheath, however, on reaching the iliac fossa , becomes directly continuous with the iliac fascia, covering the iliacus muscle, and thus it is necessary to consider these two together in that region. This iliac fascia, then, is attached along the whole iliac crest and ilio -lumbar ligament. Then it extends over the psoas , on the inner border of which it is attached to the sacrum and brim of the true pelvis, and ilio-pectineal eminence, and is continuous with the pelvic fascia. Along Poupart's ligament it fuses with the transversalis fascia, save where the external iliac vessels emerge to form the femoral vessels, the transversalis fascia at this point joining in front of, and the iliac fascia behind, the vessels, to form their sheath (femoral sheath). Thus the ilio-psoas muscle and anterior crural nerve enter the thigh through a compartment composed of fascia and bone, which is closed, save for the communication with the psoas above, and with the pelvis below and to the inside. Under the iliac fascia the external iliac, by its circumflex iliac branch, anastomoses with the ilio -lumbar branch of the internal iliac. The internal surface of the abdominal cavity, then, is lined by a continuous fascial covering, variously named at different parts, the chief portions being the transversalis and iliac fasciae. On the deep surface of the fascia lies a layer of extraperitoneal tissue, which fills in the furrow^ between the muscles, thus presenting a fairly regular abdominal surface, and in which the kidneys , ureters , renal, colic, and spermatic vessels, and iliac vessels and lymphatic glands are embedded. (The anterior crural nerve and lumbar nerves, on the other hand, are under, or external to, the fascia.) On the inner surface of the extraperitoneal tissue, again, the peritoneum lies. Abscesses in this region may occur either in the extraperitoneal tissue or under the psoas fascia. Extraperitoneal abscesses may arise from appendix, kidney, a parametritis , etc. ; may be of considerable size and widely spread. Such abscesses tend to point above Poupart or to enter the pelvis. Those which occur under, or external to, the transversalis fascia generally point at the iliac crest or above Poupart ; they rarely extend along the inguinal canal into the scrotum. Sometimes, by following the last intercostal or ilio-hypogastric nerves, they may pierce the lumbar fascia, or may pierce the quadratus lumborum , and then, coming through the external oblique, appear at Petit's triangle. Those which occur in the psoas sheath arise generally from tubercular disease of the dorsal or upper lumbar vertebrae ( Pott's disease). Where the disease is in the dorsal region, the tubercular debris is first extruded into the posterior mediastinum in which it gravitates downwards, until arrested by the diaphragm, whence, passing under the internal arcuate ligament in company with the psoas muscle, it enters the abdomen within the psoas sheath. This sheath directs it down the posterior abdominal wall, across the blade of the ilium , under Poupart's ligament, through the special iliac compartment already described, in which position it lies to the outside of the femoral vessels. Then the abscess passes under the vessels, reaches the lesser trochanter , and frequently turns up again and overlaps the vessels from the inside. While this is the typical course of a psoas abscess, the pus may sometimes escape from the psoas sheath, as for example by following one of the lumbar arteries between the transverse processes of the lumbar vertebrae, and then, running outwards on the posterior surface of the quadratus lumborum , pierce the origin of the transversalis , and also the internal oblique, and finallv present in the triangle of Petit-the triangular interval whose base is formed by the highest point of the crest of the ilium , while the sides are formed by the free border of external oblique anteriorly , and the latissimus dorsi posteriorly . The floor is formed by the internal oblique. (Above the triangle the latissimus dorsi overlaps the external oblique.) Sometimes also the pus may gravitate into the pelvis through the communication with the pelvic fascia. On the other hand, pus from acetabular disease, or hip disease where the acetabulum is eroded and perforated, may extend upwards, and so simulate a psoas abscess.

21. The psoas sheath arises from the front of the bodies of the lumbar vertebra runs outwards and fuses with the anterior, middle and posterior layers of fascia to form the lumbar aponeurosis . commences at the internal arcuate ligament of the diaphragm, being derived from the diaphragmatic portion of the transversalis fascia on reaching the iliac fossa , becomes directly continuous with the iliac fascia, covering the iliacus muscle This iliac fascia, then, is attached along the whole iliac crest and ilio -lumbar ligament. Then it extends over the psoas , on the inner border of which it is attached to the sacrum and brim of the true pelvis, and ilio-pectineal eminence, and is continuous with the pelvic fascia. Along Poupart's ligament it fuses with the transversalis fascia, save where the external iliac vessels emerge to form the femoral vessels, the transversalis fascia at this point joining in front of, and the iliac fascia behind, the vessels, to form their sheath (femoral sheath). Thus the ilio-psoas muscle and anterior crural nerve enter the thigh through a compartment composed of fascia and bone, which is closed, save for the communication with the psoas above, and with the pelvis below and to the inside.

22. As the vertebral bodies collapse into each other, a sharp angulation ( gibbus or kyphos ) develops. cord damage →pressure by the abscess, granulation tissue, sequestra or displaced bone, or (occasionally) ischaemia from spinal artery thrombosis. With healing → vertebrae recalcify ,bony fusion may occur Spine is usually ‘unsound’, and flares are common, resulting in further illness and further vertebral collapse. .

23. Clinical features Complaints There is usually a long history of ill-health and backache; in late cases a gibbus deformity is the dominant feature. Constitutional symptoms antedate local spinal involvement- weakness, anorexia, night sweats and cries, evening and afternoon rise of temperature, loss of appetite and weight Pain Back pain commonest- diffuse, later localised Referred pain arm (cervical) Girdle pain (dorsal) Abdomen( dorsolumbar ) Groin (lumbar) Sciatica (sacral)

24. Stiffness- very early symptom Paravertebral muscles go into spasm to prevent movement Cold abcess Swelling or problems secondary to compression effects- dysphagia , dyspnoea Deformity – gibbus under 10 years with thoracic spine TB - pectus carinatum Paraplegia -Back stiffness, weakness, parasthesia of lower extremities- heralds onset of paraplegia Concurrent pulmonary TB is a feature in most children under 10 years with thoracic spine involvement.

25. Examination GPE Any active or healed primary lesion Diabetes, hypertension, jaundice Malnourished Gait Cautious and careful Short steps to avoid jerking the spine C spine- may support head with both hands under chin and twists the whole body to look sideways

26. Attitude and deformity Very protective attitude Muscle spasm straightens the spine Dorsal spine- gibbus or kyphus Kyphosis (95%) Scoliosis (5%) Lordosis Paravertebral thickening

27. Typical attitudes Upper cervical Lower cervical Upper thoracic Lower thoracic Upper lumbar Lower lumbar Wryneck Military position Shoulders raised, arms backwards Alderman’s gait Prominent abdomen Increased lordosis

28. Para-vertebral swelling Cold abscess Fullness or swelling on the back, chest wall or anteriorly Fluctuant, may be tense Tenderness Spinous process of involved vertebra is tender to percuss / when attempt is made to rotate the vertebra

29. Pronounced wasting of back muscles Sinuses Movements Decreased in all directions especially forward, flexion Coin test Spastic or flaccid paraplegia LMN features - cauda equina lesion Neurological examination- Upper and lower limbs Motor, sensory, reflexes Urinary and bowel functions assessed

30. POTT’S PARAPLEGIA Most feared complication Compression of spinal cord 10- 30% Most often with tb of dorsal spine Spinal cord terminates below L1 Spinal cord is smallest in this region(0.63 cm) (C and L-1.27cm) Normal curve encourages marked kyphosis ALL in dorsal region loosely confines the abcess

31. Causes Inflammatory Oedema Granulation tissue Abcess Caseous tissue Mechanical Tubercular debris Sequestra Stenosis of vertebral canal Internal gibbus Intrinsic Prolonged stretching Infective Endocarditis Pathological dislocation Tuberculous meningomyelitis syringomyelia Infarction Spinal tumor disease Extradural granuloma Spinal tumour syndrome Tuberculoma Peridural fibrosis

32. Seddon’s classification Early-onset paresis (usually within 2 years ) pressure by inflammatory oedema , an abscess, caseous material, granulation tissue or sequestra . CT and MRI may reveal cord compression. prognosis for neurological recovery following surgery is good. Late-onset paresis direct cord compression from increasing deformity, or (occasionally) vascular insufficiency of the cord recovery following decompression is poor.

33. Clinical features Early onset- lower limb weakness, upper motor neuron signs, sensory dysfunction and incontinence. Late onset- clumsiness, twitching, increased reflexes, clonus , + ve Babinski sign Motor functions usually affected first

34. Paralysis follows these stages in order of severity- muscle weakness, spasticity, incoordination - Pressure on corticospinal tracts whish are placed anteriorly in the cord, more sensitive to pressure paraplegia in extension- tone increased due to absence of normal corticospinal inhibition flexor spasm paraplegia in flexion- absence of paraspinal functions in addition to corticospinal functions flaccid paraplegia- all transmission across cord stops

35. Cotran , Robin and Kumar’s Grading Grade I - Negligible, pt is unaware, physician detects ankle clonus and upgoing plantar Grade II- Mild, pt aware, complains of clumsiness, incoordination or spasticity but walks with support Grade III- Moderate, non-ambulatory, paralysis in extension, sensory deficit<50% Grade IV -Severe grade III + paraplegia in flexion with severe muscle spasm+ sphincter disturbance+sensory deficit >50%

36. Clonus if the first most prominent early sign of Pott’s disease Sense of position , vibration last to disappear Sudden paraplegia : Thromboembolism Pathological dislocation Rapid accumulation of infected material HIV resurgence of TB, Spinal TB is AIDS defining . prone-opportunistic infections and atypical mycobacterial infections Multiple vertebrae ,severe deformity, primary epidural abscess