1. Bone and joint infections 2 -Acute suppurative arthritis. -Tuberculosis. pathology treatmentdiagnosis

2. 2 Acute suppurative arthritis. -Acute suppurative arthritis. -A joint can become infected by 1-direct invasion through penetrating wound, intra- articular injection or arthroscopy. 2-direct spread from an adjacent bone abscess. 3-blood spread from a distant site. -The causal organism is Staphylococcus aureus. -Haemophilus influenzae in children between 1 and 4 years old. -Occasionally Streptococcus, Escherichia coli and Proteus. - Neisseria gonorrhoeae is the commonest cause of septic arthritis in adults. In infants it is often difficult to tell whether the infection started in the metaphyseal bone and spread to the joint or vice versa.

3. 3 Pathology = -Pathology = - -The usual trigger is a haematogenous infection which settles in the synovial membrane. -there is an acute inflammatory reaction with a serous or seropurulent exudate and an increase in synovial fluid. -as pus appears in the joint, articular cartilage is eroded and destroyed, partly by bacterial enzymes and partly by proteolytic enzymes released from synovial cells, inflammatory cells and pus. -In infants = the entire epiphysis which is still largely cartilaginous, may be severely damaged. -In older children = vascular occlusion may lead to necrosis of the epiphyseal bone. -in adults = the effects are usually confined to articular cartilage,

4. 4 But in late cases, there may be extensive erosion due to synovial proliferation and ingrowth. -If the infection goes untreated, it will spread to the underlying bone or burst out of the joint to form abscesses and sinuses. -With healing, there may be = 1- complete resolution and a return to normal. 2- partial loss of articular cartilage and fibrosis of the joint. 3-loss of articular cartilage and bony ankylosis. Or 4- bone destruction and permanent deformity of the joint.

5. 5 In the early stage (A), there is an acute synovitis with a purulent joint effusion. Then ( B ) soon the articular cartilage is attached by bacterial and cellular enzymes. Then (C) if the infection is not arrested, the cartilage may be completely destroyed. Then (D) healing leads to bony ankylosis.

6. 6 - Clinical features = -The clinical features differ somewhat according to the age of the patient= -in infants = -the emphasis is on septicaemia rather than joint pain. -the baby is irritable and refuse to feed. -there is rapid pulse and sometimes a fever. -the umbilical cord should be examined for a source of infection. -an inflamed intravenous infusion site should always excite suspicion. Special care should be taken not to miss a concomitant osteomyelitis in an adjacent bone end. - Special care should be taken not to miss a concomitant osteomyelitis in an adjacent bone end.

7. 7 -in children = -the usual features are acute pain in a single large joint ( commonly the hip or knee ). -and reluctance to move the limb ( pseudo paresis ). -The child is ill, with a rapid pulse and a swinging fever. -the overlying skin looks red and in a superficial joint swelling may be obvious. -local warmth and marked tenderness. -all movements are restricted. -in adults = -it is often a superficial joint( knee, wrist, ankle, or toe ) that is painful, swollen, and inflamed. -the patient should be questioned and examined for evidence of gonococcal infection or drug abuse.

8. 8 -patients with rheumatoid arthritis, and especially those on corticosteroid treatment, may develop a ( silent ) joint infection. -suspicion may be aroused by unexplained deterioration in the patient s general condition. Investigations = - Ultrasonography = is the most reliable method for revealing a joint effusion in early cases. -both hips or knees should be examined for comparison. -widening of the space between capsule and bone of more than 2 mm is indicative of an effusion.

9. 9 - plain x- ray = - is usually normal early on but signs to be watched for are = 1- soft tissue swelling. 2-widening of the radiographic joint space. 3-slight subluxation ( because of fluid in the joint ) 4- with E- coli infection, there is sometimes gas in the joint. 5- narrowing and irregularity of the joint space are late features. - MRI and Radionuclide imaging = -are helpful in diagnosing arthritis in obscure sites such as the sacroiliac and sternoclavicular joints.

10. 10 - Lab. Tests = - WBC, ESR and CRP are raised and blood culture may be positive. -Joint fluid aspiration = but beware -the fluid may be frankly purulent but beware = in early cases the fluid may looks clear. -WBC and Gram stain should be done immediately. -the normal synovial fluid leucocytes count is under 300 per mL. -it may be over 10 000 per mL in non infective inflammatory disorders. -But counts of over 50 000 per mL are highly suggestive of sepsis. -Gram- positive cocci are probably S.aureus. -Gram – negative cocci are either H. influenzae ( in children ) or Gonococcus ( in adults ). -samples of fluids are also sent for full microbiological examination and tests for antibiotic sensitivity.

11. 11 - differential diagnosis = 1- acute osteomyelitis. 2-Traumatic synovitis or haemarthrosis. - a history of injury does not exclude infection. Diagnosis may remain in doubt until the joint is aspirated. 3- irritable joint = ( transient synovitis ) = - the child is not really ill and there is no signs of infection. - ultrasonography may help. 4- Haemophilic bleed = histroy is usually conclusive, and aspiration will resolve any doubt. 5-Rheumatic fever. 6-Juvenile rheumatoid arthritis. 7-Sickle cell disease.

12. 12 8- Gaucher s disease = in this rare condition acute joint pain and fever can occur without any organism being found ( pseudo- ostitis ). -because of the predisposition to infection, antibiotics should be given. 9-Gout and pseudo gout = - Microscopic examination by polarized light will show the characteristic crystals.

13. 13 -Treatment = the first priority is to aspirate the joint and examine the fluid. Treatment is then started without further dely. if the aspirate looks purulent, the joint should be drained without waiting for LAB. Results. 1- general supportive care = analgesia and fluids ( i.v line ) for dehydration. 2-splintage = with hip infection, the joint should be held abducted and 30 degrees flexed on traction to prevent dislocation. 3-antibiotics = -Infants and children = flucloxacillin plus 3 rd generation cephalosporin. -Older teenagers and adults = flucloxacillin and fusidic acid, if G –ve is suspected, then 3 rd generation cephalosporin is added. -Antibiotics should be given intravenously for 4- 7 days and then orally for another 3 weeks.

14. 14 4-Drainage = - under anaesthesia the joint is opened through a small incision, drained and washed out with physiological saline. -A small catheter is left in place and the wound is closed. -suction- irrigation is continued for another 2 or 3 days. -drainage is indicated in = 1- in very young infants. 2-when the hip is involved. 3-if the aspirated pus is very thick. - Older children with early septic arthritis, involving any joint except the hip can often be treated successfully by repeated closed aspiration of the joint, but if there is no improvement within 2 days open drainage is indicated.

15. 15 5- aftercare = -if the articular cartilage has been preserved, gentle and gradually increasing active movement are encouraged. -if the articular cartilage has been destroyed, then splintage in the optimum position is therefore continuously maintained, usually by plaster until ankylosis is sound. - complications = 1- subluxation and dislocation of the hip or instability of the knee. 2-damage to the cartilaginous physis or the epiphysis in the growing child. 3-articular cartilage erosion ( chondrolysis ),is seen in older patients and this may result in restricted movement or complete ankylosis of the joint.

16. 16 Tuberculosis = -The skeletal manifestations of the disease are seen chiefly in the spine and the large joints, but the infection may appear in any bone or any synovial or bursal sheath. -Pathology = - Mycobacterium tuberculosis = ( usually human, sometimes bovine), enters the body via the lung ( droplet infection ). Or the gut ( swallowing infected milk products ), or through the skin. in contrast to pyogenic infection, it causes a granulomatous reaction which is associated with tissue necrosis and caseation. -in contrast to pyogenic infection, it causes a granulomatous reaction which is associated with tissue necrosis and caseation.

17. 17 - Primary complexSecondary spreadTertiary lesion

18. 18 - Primary complex = - The initial lesion in lung, pharynx or gut is a small one with lymphatic spread to regional lymph nodes, this combination is the primary complex. -usually the bacilli are fixed in the nodes and no clinical illness results, but occasionally the response is excessive with enlargement of glands in the neck and abdomen. -Even though there is often no clinical illness, the initial infection has two important sequels = Bacilli may survive for many years within nodes which are apparently healed or even calcified. The body has been sensitized to the toxin, and if re-infection occur, the response is quite different, and the lesion will be more destructive and easily spread.

19. 19 - Secondary spread = - if resistance to the original infection is low, widespread dissemination via the blood stream may occur, giving rise to miliary T.B. -more often blood spread occurs months or years later, perhaps during a period of lowered immunity, and the bacilli are deposited in extra-pulmonary tissues. -some of these foci develop into destructive lesion, which is called Tertiary lesion. -Tertiary lesion = - bone and joints are affected in about 5 % of patients with T.B, - There is a predilection for the vertebral bodies and the large synovial joints.

20. 20 - The characteristic microscopic lesion is tuberculous granuloma - a collection of epitheloid and multinucleated giant cells surrounding an area of necrosis with round cells mainly lymphocytes around the periphery. -If the synovium is involved, it becomes thick and oedematous giving rise to a marked effusion. -A pannus of granulation tissue may extend from the synovial reflections across the joint, articular cartilage is slowly destroyed though the rapid and complete destruction elicited by pyogenic organisms does not occur in the absence of secondary infection. - At the edge of the joint, there may be active bone erosion, and the increased vascularity causes local osteoporosis.

21. 21 -if unchecked, caseation and infection extend into the surrounding soft tissues to produce a cold abscess. ( cold only in comparison to a pyogenic abscess. -This may burst through the skin, forming a sinus or tuberculous ulcer, or it may track along the tissue planes to reach a distant site. -Secondary infection by pyogenic organisms is common. - If the disease is arrested at an early stage, healing may be by resolution. - If articular cartilage has been severely damaged, healing is by fibrosis and incomplete ankylosis with progressive joint deformity.

22. 22 - The disease may begin as synovitis ( A ), or osteomyelitis (B), from either, it can extend to become a true arthritis ( C ), not all the cartilage is destroyed and healing is usually by fibrous ankylosis ( D ).

23. 23 clinical features = -clinical features = - -the patient usually child or young adult. Complains of pain and swelling in a superficial joint. -in advanced cases, there may be attacks of fever, night sweats, lassitude and loss of weight. -Night cries = the joint, splinted by muscle spasm during the walking hours, relaxes with sleep and the inflamed or damaged tissues are stretched or compressed, causing sudden episodes of intense pain. -Muscle wasting is characteristic and synovial thickening is often striking. -Regional lymph nodes may be enlarged and tender. -movements are limited in all directions. -as articular erosion progresses the joint become stiff and deformed.

24. 24 - in T.B of the spine = - pain may be deceptively slight, so the patient may not present until there is a visible abscess ( usually in the groin or the lumbar region to one side of the midline ). Or until collapse causes a localized kyphosis. -Occasionally the presenting feature is weakness or instability in the lower limbs. X- ray = - soft tissue swelling and peri-articular osteoporosis are characteristic. -the bone ends take on a ( washed – out ) appearance and the articular space is narrowed.

25. 25 - in children the epiphysis may be enlarged, probably due to long standing hyperaemia. -later on there is erosion of the subarticular bone, characteristically this is seen on both sides of the joint, indicating an inflammatory process starting in the synovium. -cystic lesions may appear in the adjacent bone ends but there is little or no periosteal reaction. in the spine = - in the spine = -The characteristic appearance is one of bone erosion and collapse around a diminished intervertebral disc space. -the soft tissue shadows may define a paravertebral abscess.

26. 26 - LAB. Investigations = -ESR is usually increased, and there may be relative lymphocytosis. -the Mantoux or Heaf test will be positive. ( sensitive but not specific). -If synovial fluid is aspirated, it may be cloudy, its protein concentration is increased and WBC is elevated. -acid – fast bacilli are identified in synovial fluid in 10 – 20 % of cases and cultures are positive over half. -a synovial biopsy is more reliable, it will show the characteristic histological features and cultures are positive in 80 % of patients who have not received antimicrobial treatment.

27. 27 - Differential Diagnosis = 1- Transient synovitis = it always settles down after a few weeks of rest in bed. If it recurs then further investigations ( even biopsy ) are indicated. 2- monoarticular rheumatoid arthritis = if it starts in a single large joint,then only the biopsy can differentiate. 3-subacute arthritis = such as amoebic dysentery or brucellosis are sometimes complicated by arthritis. -History, exam. And pathological investigation can differentiate. 4-haemorrhagic arthritis. = history and exam. 5-pyogenic arthritis =in long standing cases, it may be difficult to exclude an old septic arthritis.

28. 28 Treatment = - Treatment =

29. 29 -Rest = those who are diagnosed and treated early are kept in bed only until pain and systemic symptoms subside, and then are allowed restricted activity until the joint changes resolve ( usually 6 months to a year ). those with progressive joint destruction may need a longer period of rest and splintage to prevent ankylosis in a bad position.

30. 30 -Chemotherapy =

31. 31 the most effective treatment is a combination of antituberculous drugs, which should always include Rifampicin and Isoniazid. - Note = the most effective treatment is a combination of antituberculous drugs, which should always include Rifampicin and Isoniazid. -During the last decade the incidence of drug resistance has increased and this has led to addition various potentiating drugs to the list. -The following is one of several recommended regimens = 1- initial ( intensive phase treatment ) = consists of - isoniazid 300 – 400 mg - rifampicin 450 – 600 mg and - fluoroquinolones 400 – 600 mg daily for 5-6 months

32. 32 2- then the ( Continuation phase treatment ) = -it involves the use of Isoniazid and Pyrazinamide 1500 mg per day for 4 and half months and Isoniazid and Rifampicin for another 4 and half months. -The purpose is to eliminate the persisters, slow- growing, intermittently growing, dormant or intracellular Mycobacteria. 3- then the ( Prophylactic phase ) = -consisting of isoniazid and ethambutol 1200 mg per day for further 3 or 4 months. during the entire treatment period drugs and dosage may have to be adjusted and modified depending on patient Note = during the entire treatment period drugs and dosage may have to be adjusted and modified depending on patient age, size, general health and side effects.

33. 33 -Operation = -Operative drainage of a tuberculous focus is seldom necessary nowadays. However, a cold abscess may need immediate aspiration or drainage. -if the joint is painful and the articular surface is destroyed, then arthrodesis or replacement arthroplasty is considered. -there is always some risk of reactivation and it is essential to give chemotherapy for 3 months before and after the operation. Thank you Dr. Firas Abdalhadi Alobidi