Bacterial, Tubercular and other infection of bones in children cause, c/f, invest, mnx

1. Bone And Joint Infection In Children
Dr Sunetra Roy
DCH, DNB (PEDIATRICS)

2. Introduction
 Bone infections in children are relatively common and
important because of their potential to cause permanent
disability.
 Early recognition and prompt institution of appropriate
medical and surgical therapy minimize permanent
damage.
 The risk is greatest if the physis (the growth plate of
bone) is damaged.

4. Epidemiology
 The median age 6 yr.∼
 Incidence = 1:5,000
 Boys > Girls
 No predilection for any Race (Except Sickle cell disease – Blacks)
 In Previously healthy children- mostly hematogenous.
 Minor closed trauma - common preceding event ( 30% cases)∼
 Infection of bones can follow penetrating injuries or open
fractures.
 Following orthopedic surgery.
 Impaired host defenses increases the risk of skeletal infection.

5. Etiology of Osteomyelitis and Septic Arthritis
Infant 0-2 months Staphylococcus aureus
Streptococcus agalactiae
Gram-negative enteric bacteria
Candida
<5 y Staphylococcus aureus
Streptococcus pyogenes
Streptococcus pneumoniae
Kingella kingae
Haemophilus influenzae type b
>5 y S. aureus
S. Pyogenes
Adolescent Neisseria gonorrhoeae

6. MOST COMMON CLINICAL
ASSOCIATION
MICROORGANISM
Frequent microorganism in any type of
osteomyelitis
Staph. aureus
Common in nosocomial infection Enterobacteriaceae, Pseudomonas
aeruginosa, candida spp.
Foreign body–associated infection Coagulase-negative staphylococci or
other skin flora, atypical mycobacteria
Decubitus ulcers Streptococci and/or anaerobic bacteria
Populations in which tuberculosis is
prevalent
Mycobacterium tuberculosis
Exposure to kittens Bartonella henselae
Immunocompromised patients Aspergillus spp., Candida albicans, or
Mycobacteria spp.
Microorganisms Isolated fromPatients with Osteomyelitis

7. Pathogenesis
In the metaphysis, nutrient arteries branch into
non-anastomosing capillaries under the
physis make a sharp loop before entering
venous sinusoids draining into the marrow
( Hair-pin Ends)
Blood flow, sluggish and provides an ideal
environment for bacterial seeding
Relative paucity of phagocytic cells in this
area

8. Pathogenesis- In neonates and young infants
 Transphyseal blood vessels connect
the metaphysis and epiphysis
 commonly pus from the metaphysis
enters the joint space
 Result in abnormal growth and bone
or joint deformity
Joint involvement takes place when
the metaphysis is intra- articular as in
hip, ankle, shoulder, and elbow joint
or when subperiosteal pus ruptures
into the joint space

9. Pathogenesis- In child >18 months
 Spread through the cortex.
 Porous metaphyseal cortex provides easy assess for the exit
of exuate or pus
 Elevates the periosteum (thick periosteum loosly adherent to
the cortex)
 Subperiosteal pus collection(further impairing blood supply to
the cortex and metaphysis)
 Enough periosteal destruction soft tissue abcess.→

10. Pathogenesis…In later childhood and adolescence
The growth plate closes, hematogenous osteomyelitis more often
begins in the diaphysis and can spread to the entire
intramedullary canal.
Closed plate is relativley resistant to spread of infection.
 The periosteum becomes more adherent, favoring pus to
decompress through the periosteum
 The fluid formed seeks the path of least resistance from the
metaphysis

12. Clinical Features
 Age - greater in infants and toddlers than in older
children
 Sex - boys > girls, usually 2 : 1
 Signs and symptoms are highly dependent on the age of
the patient
 The initial s/s are often subtle
 The hallmark of osteomyelitis is fever plus localised bony
tenderness
 Neonates may exhibit pseudoparalysis or pain with movement
of the affected extremity- Diaper changes
 Half of neonates do not have fever and may not appear ill

13. Clinical Features…
 Signs and symptoms
 Older infants and children are more likely to have fever,
pain, and localizing signs such as edema, erythema,
and warmth
 With involvement of the lower extremities, limp or refusal to
walk
 Careful Physical examination may reveal focal bony
tenderness.

14. Distribution of Affected Bones in Acute Hematogenous
Osteomyelitis
• Usually only a single site
of bone or joint
involvement, the exception
is osteomyelitis in
neonates.
• Several bones are
infected in <10% of cases;
BONE %
Femur 23-28
Tibia 20-24
Humerus 5-13
Radius 5-6
Phalanx 3-5
Pelvis 4-8
Calcaneus 4-8
Ulna 4-8
Metatarsal ∼2
Vertebrae ∼2
Sacrum ∼2
Clavicle ∼2
Skull ∼1

15. Diagnosis
 Children with acute bone pain and systemic signs of
sepsis should be considered to have acute hematogenous
Osteomyelitis until proved otherwise.
 Diagnosis may be established if a patient fulfills two of
the following criteria:
1. Bone aspiration yield pus
2. Bacterial culture of bone or blood positive
3. Presence of the classical s/s of acute osteomyelitis
4. Radiographic changes typical for osteomyelitis.

16. LABORATORY FINDINGS
 No specific laboratory tests.
 Elevations in peripheral WBC, ESR, and CRP –
 ESR-Nonspecific acute phase reactant
 Increased 48-72 hrs
 Increased in 90% of cases
 Not affected by antibiotic tx
 CRP- Increased in 98% of cases
 Blood culture-
 Positive in 30-50%
 Decreased with antibiotic
 48 hours to get most organisms

17. Radiology
 Plain xray
 Sensitivity 43-75%
 Specificity 75-83%
 Soft tissue swelling 48hrs
 Periosteal reaction 5-7days
 Osteolysis 7-14 days of infection(need 30-50% bone loss)
 Magnetic Rsonance Imaging (MRI)
 Computed Tomography (CT)
 Radionuclide Study

18. Plain radiography
 Bone changes - not seen for at least 10-14 days after the
onset of infection.
• Plain radiographs-normal in
the first 7 to 10 days
• Soft tissue swelling with loss
of the normal soft tissue
planes is seen before bone
changes become apparent
•Periosteal elevation or thickening -
new bone formation, pus, or
reactive edema from adjacent soft
tissue infection

22. Radionuclide imaging…
 Radionuclide imaging can be valuable in suspected bone
infections especially if multiple foci are suspected
 Bone scans in acute haematogenous osteomyelitis have a
sensitivity of 84% to 100% and a specificity of 40% to
96%.
(N Susan Stott, Journal of Orthopaedic Surgery; Review
article: Paediatric bone and joint infection)
 Can detect osteomyelitis within 24–48 hr after onset
of symptoms
 The sensitivity in neonates is much lower owing to
poor bone mineralization

23.  A) Plain radiographs of the ankle demonstrate deep soft tissue swelling inferior to
the medial malleolus. B) A technetium 99m bone scan shows increased uptake in
the distal tibia in the blood flow and bone uptake (four hour) phases.
Early Osteomyelitis, with pain and fever
Bone Scan…
Tc99
24-48hrs +ve
Decreased uptake
in early phase d/t
increased pressure

24. Ultrasound
 can detect features of osteomyelitis several days earlier Xray
(predominately in children).
 Acute osteomyelitis is recognized by elevation of the periosteum
by a hypoechoic layer
 Soft tissue abscesses related to chronic osteomyelitis are
identified as hypoechoic or anechoic fluid collections, which may
extend around the bony contours.
 Finally, US guided aspiration of joints
MRI
 have comparable positive predictive value to radionuclide
imaging in acute osteomyelitis
 particularly useful in the evaluation of vertebral osteomyelitis
and diskitis

27. Bone Aspiration
 A bacteriologic diagnosis is made by culturing the
involved bone or pus, once a clinical diagnosis of acute
osteomyelitis is established.
 Useful to determine whether an abscess is present.
 The organism detection rate is increased to 75% to 80%
by aspiration of the affected bone
 K. kingae may need to be identified by polymerase chain
reaction
 Also useful in determining the future course of therapy
of the child

28. Differential Diagnosis
 Trauma
 Cellulitis
 Myositis and pyomyositis
 Leukemia
 Neuroblastoma with bone involvement
 Primary bone tumors (Ewing sarcoma)
 Septic arthritis

29. Classification-
Acute hematogenous Osteomyelitis
Subacute hematogenous Osteomyelitis
Chronic Multifocal Osteomyelitis
Parameters
Subacute Acute
WBC Frequently normal Frequently elevated
ESR Frequently elevated Frequently elevated
Blood Cultures Rarely Positive 50% Positive
Bone Cultures 60% Positive 90% Positive
Localization Diaphysis, metaphysis,
epiphysis, cross physis
Metaphysis
Pain Mild to Moderate Severe
Systemic Illness No Fever, malaise
Loss of function No or minimal Marked
Prior antibiotics 30%-40% Occasional
Initial radiograph Frequently abnormal Bone normal

30. Brodie’s abscess, central oval lucency surrounded
By reactive sclerosis usually within or close to the
Metaphysis and the lesion may extend across the
physis.

32. Garré sclerosing osteomyelitis, or chronic nonsuppurative sclerosing
osteomyelitis, is a form of chronic osteomyelitis. Mild inflammation and infection
lead to subperiosteal bone deposition. It is frequently asymptomatic. The
characteristic radiographic appearance is an area of periosteal proliferation
surrounded by successive layers of condensed cortical bone (arrows), described
as an onion skin appearance.

33. TREATMENT OF OSTEOMYELITIS

34. Duration of antibiotic therapy
 Most infections- eg S. aureus, minimal duration is 21-28 days, if
prompt resolution of signs and symptoms (within 5-7 days)
and the CRP and ESR have normalized;
 a total of 4-6 wk of therapy may be required.
 For group A streptococcus, S. pneumoniae, or H. influenzae
type b, treatment duration maybe shorter.
 A total of 7-10 postoperative days of treatment is adequate
for Pseudomonas osteochondritis when thorough curettage of
infected tissue has been performed.
 Immunocompromised patients, mycobacterial or fungal
infection -require prolonged courses of therapy.

35. Indication of Surgical Treatment
 Abscess collection (Subperiosteal , soft tissue, or
intramedullary)
 Patient is not responding to appropriate antibiotic
therapy after a negative bone aspiration
(If a child with acute hematogenous osteomyelitis does not show
symptomatic improvement with decrease in swelling and
tenderness after 36-48 hrs of appropriate antibiotic treatment, the
bone should be aspirated again and consideration given to surgical
drainage)
 In subacute Osteomyelitis when debridement is
necessary (granulation tissue within the cavity even
though no pus)
 Radiographic lesion, sequestrum

36. Complications
 Bone abscess
 Bacteremia
 Fracture
 Loosening of the prosthetic implant
 Overlying soft-tissue cellulitis
 Draining soft-tissue sinus tracts
 Growth disturbance

37. Prognosis
 Improvement in signs and symptoms is rapid when timely
intervened.
 Failure to improve or worsening by 72 hr requires review of
antibiotic therapy, the need for surgical intervention, or the
correctness of the diagnosis.
 Recurrence of disease and development of chronic infection after
treatment occur in <10% of patients.

38. Septic Arthritis
 An infection of a synovial joint which may occur in all age
groups in children
 Has a specific infantile form affecting the infant from birth
to the first year of life
 Relatively uncommon

39. Septic Arthritis
 More common in infants and toddlers than in older
children
 Half of all cases occur by 2 yr of age and three fourths of all
cases occur by 5 yr of age
 Immuno-compromised hosts may have a higher incidence

40. ETIOLOGY

41. Pathogenesis
 Results from hematogenous seeding of the synovial space
 Organisms enter the joint space by direct inoculation or
extension from a contiguous focus.
 The synovial membrane (rich vascular supply and lacks a
basement membrane) providing an ideal environment for
hematogenous seeding.
 Cytokines stimulate chemotaxis of neutrophils into the joint
space, proteolytic enzymes and elastases are released by
neutrophils cartilage damage
 Increased pressure in joint space from can compromise the
vascular supply and induce pressure necrosis of the cartilage.

42. Pathogenesis….
 May be associated with acute osteomyelitis esp in the
proximal femur
 Routes of Infection-
 Usually hematogenous
 Trauma (penetrating injuries)
 Post procedure (arthroscopy, prosthetic joint surgery, intra-
articular steroid injection, and orthopedic surgery)

43. Pathology
 Acute inflammatory reaction.
 Degradation of the articular cartilage begins within 8
hours of infection.
 In neonates, metaphyseal osteomyelitis is often
associated with septic arthritis due to the presence of
transphyseal blood vessels that disappear by age 6 to 12
months
 Sixty to 100% of neonates with septic arthritis will
have adjacent osteomyelitis

44. CLINICAL MANIFESTATIONS
 Hot, swollen joint painful on any movement indicates a septic
arthritis until proved otherwise
 In neonate, present as a pseudo-paralysis of one limb
 Erythema and edema of the skin and soft tissue overlying
the site of infection are seen earlier in suppurative
arthritis than in osteomyelitis
 Joint kept at position of ease.

45. Distribution of Affected Joints in Acute
Suppurative Arthritis
BONE %
Knee ∼40
Hip 22-40
Ankle 4-13
Elbow 8-12
Wrist 1-4
Shoulder ∼3
Interphalangeal <1
Metatarsal <1
Sacroiliac <1
Acromioclavicular <1
Metacarpal <1
Toe ∼1

46. Investigations
 The investigations are similar to those required in
osteomyelitis
 Blood culture
 Aspiration of the joint fluid for Gram stain and culture,
definitive diagnostic technique and provides the optimal
specimen for culture to confirm the diagnosis
 Elevations of WBCs, ESR, and CRP are very sensitive for joint
infections but are nonspecific

47.  Synovial fluid analysis – Cell Counts >50,000-100,000 cells/mm3
generally
indicate an infectious process. Synovial fluid characteristics of septic
arthritis can suggest infection but are not sufficiently specific to exclude
infection.
Infected Fluid
 Appearance / Clarity: Turbid to very turbid (N- Clear and colorless)
 Viscosity: Greatly reduced (similar to water) (N-Very viscous)
 Leukocytes / cubic cm: 15,000- >200,000 (N : Average 63; Range: 13-180.)
usually >50,000 and >100,000 is virtually diagnostic
 Percent polymorphoneuclear: 50-100% (N-<25%)
90% almost always indicates infection
 Mucin clot: Poor to very poor (N-Good)
 Glucose level difference versus plasma: >40 mg/100ml less than plasma (N-
Within 10 mg/100ml of plasma concentration)

48. Differential Diagnosis
Depends on the joint or joints involved and the age of the
patient
 Hip
 toxic synovitis, Legg-Calvé-Perthes disease, slipped capital femoral
epiphysis, psoas abscess, and proximal femoral, pelvic, or vertebral
osteomyelitis as well as diskitis
 Knee
 distal femoral or proximal tibial osteomyelitis, pauciarticular
rheumatoid arthritis, and referred pain from the hip
 Others like trauma, cellulitis, pyomyositis, sickle cell disease,
hemophilia, and Henoch-Schönlein purpura, also Reactive
arthritis, Acute rheumatic fever (multiple joints involved)

50. Radiographic Evaluation
 Plain Xrays
 Widening of the joint capsule, soft-tissue edema, and obliteration of
normal fat lines
 Ultrasonography
 helpful in identifying effusions in deep joints such as the hip
 may serve as an aid in performing hip aspiration
 CT
 MRI
 Both are useful in confirming the presence of joint fluid in patients
with suspected osteoarthritis infections
 MRI may be useful in excluding adjacent osteomyelitis
 Radionuclide studies
 In suppurative arthritis, three-phase imaging with technetium-99
methylene diphosphonate shows symmetric uptake on both sides of
the joint, limited to the bony structures adjacent to the joint

51. TREATMENT

52.  Hip joint
 An infection of the hip joint is an emergency, as potential for
the development of avascular necrosis of the femoral head.
 Aspiratiion through Fluroscopy guided
For joints other than the hip, daily aspirations of synovial fluid
may be required
• If fluid continues to accumulate after 4–5 days, arthrotomy is
needed

53. APView of Left Hip showing avascularnecrosis left head of
femur

54.  In selected patients, obtaining a plain radiograph of the joint
before completing therapy can provide evidence (typically
periosteal new bone) of a previously unappreciated contiguous
site of osteomyelitis that would likely prolong antibiotic
treatment.
 Oral antibiotics can be used to complete therapy once the
patient is afebrile for 48-72 hr and is clearly improving

55. Monitoring of patient
 Failure to improve or worsening by 72 hr requires
 review of the appropriateness of the antibiotic therapy
 the need for surgical intervention
 the correctness of the diagnosis
 Failure of either of acute-phase reactants to follow the
usual course should raise concerns about the adequacy of
therapy
 Recurrence of disease and development of chronic
infection after treatment occur in <10% of patients.

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