# Septic arthritis

Septic arthritis

Joint infection is usually secondary to haematogenous spread but direct inoculation can occur, for example during a neonatal venepuncture. Diagnosis can be di ffi cult in the very young and in those presenting with overwhelming sepsis. Neonates, children with immunocompromise and those with sickle cell 

Figure 44.38
Anteroposterior pelvic radiograph of a child with spastic
cerebral palsy. The right hip is dislocated: none of the head lies medial
to the vertical
Perkins line. The acetabulum is dysplastic. The left hip
, knee
is in abduction. There is often a ‘windswept’ appearance with one leg
stiff in abduction and the other stiff in adduction. The red line demon
-
strates the pelvic obliquity; many children also have a
scoliosis. Note
the signi
/f_i
cant constipation; this can cause signi
/f_i
cant pain, which will
increase spasm and increase the pain still further.

the di ff erentiation between joint sepsis and transient synovitis of  the hip can also be di ffi cult. Classically , the child presents with pain, fever and a reluctance to move the joint; in the lower limb, this implies a reluctance to weight bear. On examination, local tender ness and painful restriction of  movement ar e apparent and in superficial joints inflammation may be obvious, with a hot, swollen joint. Investigations include FBC, ESR, CRP and blood cul tures. Plain radiographs help e xclude other diagnoses and may identify osteomyelitis. Ultrasound scans of  deep joints, such as the hip, will identify joint e ff usions ( Figure 44.39 ). MRI is considered the investigation of  choice b ut this resource is not available to all (in a timely manner) and, in young children, it requires a general anaesthetic. Good clinical skills, regu lar patient review and a high index of  suspicion are still the most valuable tools. Four clinical predictors can di ff erentiate between septic arthritis and transient synovitis ( Table 44.17 Pus in a joint is destructive: the proteases produced by leu kocytes destroy both the bacteria and the collagen matrix of the articular cartilage. A VN may occur secondary to pressure e ff ects or ischaemic infarction. The treatment of  a presumed septic arthritis therefore requires the prompt removal of pus from the joint and appropriate adequate antibiotic therapy . Pain relief  and rest are also important, as are the general health and nutrition of  the patient. The joint is aspirated and, if  pus is confirmed, a formal washout is mandatory; standard teaching states that the joint must be opened, irrigated and free drainage encouraged via the capsulotomy . Recent literature supports repeated aspiration/irrigation via a large-bore cannula or a small arthroscope for all joints except the hip. Antibiotic usage is guided by local hospital policy , the source of  the infection, the Gram stain and, in due course, the culture and sensitivity of  the organism identified. Joint instability , particularly in the hip joint ( Figure 44.40 ), may require the reduced joint to be splinted while the inflammatory process settles. /uni25CF /uni25CF /uni25CF /uni25CF Hans Christian Joachim Gram , 1853–1938, Professor of  Pharmacology (1891–1900) and of  Medicine (1900–1923), Copenhagen, Denmark, described this method of  staining bacteria in 1884. cus aureus . Streptococcal infection is also common and other organisms are more prevalent in certain age groups, e.g. the neonate, in certain conditions, e.g. sickle cell disease, or in cer - tain countries. The Haemophilus influenzae type B (Hib) vaccine - has essentially eliminated H. influenzae as a cause of  infection, but in some countries Kingella kingae has taken its place. Improvement is judged clinically and by monitoring the inflammatory markers. Reaccumulation of  pus does occur and - must be suspected and treated promptly if the child fails to improve. Summary box 44.21 Septic arthritis - /uni25CF /uni25CF ). /uni25CF - /uni25CF /uni25CF 

TABLE 44.17
Septic arthritis.
(a)
The clinical predictors of Kocher
et al
. (2004) for the diagnosis
of septic arthritis:
History of fever >38.5°C
Non-weight-bearing
Erythrocyte sedimentation rate >40
/uni00A0
mm/h
9
White cell count >12
/uni00A0×/uni00A0
10
/L
(b)
The value of the clinical predictors of Kocher
et al
. in
determining the likelihood of a joint being septic:
Number of positive Predicted probability of joint sepsis
predictors
0
2.0%
1
9.5%
2
35.0%
3
72.8%
4
93.0%
Diagnosis is dif
/f_i
cult in neonates and the immunocompromised
Typical presentation is pain, fever and a reluctance to move
the joint or weight bear
Investigations should include FBC, ESR, CRP , blood cultures
and appropriate imaging studies, combined with astute clinical
skills
Pus in a joint destroys articular cartilage and causes avascular
necrosis of intra-articular epiphyses
Treatment is prompt removal of pus, appropriate antibiotic
therapy, pain relief and splintage

Septic arthritis

Joint infection is usually secondary to haematogenous spread but direct inoculation can occur, for example during a neonatal venepuncture. Diagnosis can be di ffi cult in the very young and in those presenting with overwhelming sepsis. Neonates, children with immunocompromise and those with sickle cell 

Figure 44.38
Anteroposterior pelvic radiograph of a child with spastic
cerebral palsy. The right hip is dislocated: none of the head lies medial
to the vertical
Perkins line. The acetabulum is dysplastic. The left hip
, knee
is in abduction. There is often a ‘windswept’ appearance with one leg
stiff in abduction and the other stiff in adduction. The red line demon
-
strates the pelvic obliquity; many children also have a
scoliosis. Note
the signi
/f_i
cant constipation; this can cause signi
/f_i
cant pain, which will
increase spasm and increase the pain still further.

the di ff erentiation between joint sepsis and transient synovitis of  the hip can also be di ffi cult. Classically , the child presents with pain, fever and a reluctance to move the joint; in the lower limb, this implies a reluctance to weight bear. On examination, local tender ness and painful restriction of  movement ar e apparent and in superficial joints inflammation may be obvious, with a hot, swollen joint. Investigations include FBC, ESR, CRP and blood cul tures. Plain radiographs help e xclude other diagnoses and may identify osteomyelitis. Ultrasound scans of  deep joints, such as the hip, will identify joint e ff usions ( Figure 44.39 ). MRI is considered the investigation of  choice b ut this resource is not available to all (in a timely manner) and, in young children, it requires a general anaesthetic. Good clinical skills, regu lar patient review and a high index of  suspicion are still the most valuable tools. Four clinical predictors can di ff erentiate between septic arthritis and transient synovitis ( Table 44.17 Pus in a joint is destructive: the proteases produced by leu kocytes destroy both the bacteria and the collagen matrix of the articular cartilage. A VN may occur secondary to pressure e ff ects or ischaemic infarction. The treatment of  a presumed septic arthritis therefore requires the prompt removal of pus from the joint and appropriate adequate antibiotic therapy . Pain relief  and rest are also important, as are the general health and nutrition of  the patient. The joint is aspirated and, if  pus is confirmed, a formal washout is mandatory; standard teaching states that the joint must be opened, irrigated and free drainage encouraged via the capsulotomy . Recent literature supports repeated aspiration/irrigation via a large-bore cannula or a small arthroscope for all joints except the hip. Antibiotic usage is guided by local hospital policy , the source of  the infection, the Gram stain and, in due course, the culture and sensitivity of  the organism identified. Joint instability , particularly in the hip joint ( Figure 44.40 ), may require the reduced joint to be splinted while the inflammatory process settles. /uni25CF /uni25CF /uni25CF /uni25CF Hans Christian Joachim Gram , 1853–1938, Professor of  Pharmacology (1891–1900) and of  Medicine (1900–1923), Copenhagen, Denmark, described this method of  staining bacteria in 1884. cus aureus . Streptococcal infection is also common and other organisms are more prevalent in certain age groups, e.g. the neonate, in certain conditions, e.g. sickle cell disease, or in cer - tain countries. The Haemophilus influenzae type B (Hib) vaccine - has essentially eliminated H. influenzae as a cause of  infection, but in some countries Kingella kingae has taken its place. Improvement is judged clinically and by monitoring the inflammatory markers. Reaccumulation of  pus does occur and - must be suspected and treated promptly if the child fails to improve. Summary box 44.21 Septic arthritis - /uni25CF /uni25CF ). /uni25CF - /uni25CF /uni25CF 

TABLE 44.17
Septic arthritis.
(a)
The clinical predictors of Kocher
et al
. (2004) for the diagnosis
of septic arthritis:
History of fever >38.5°C
Non-weight-bearing
Erythrocyte sedimentation rate >40
/uni00A0
mm/h
9
White cell count >12
/uni00A0×/uni00A0
10
/L
(b)
The value of the clinical predictors of Kocher
et al
. in
determining the likelihood of a joint being septic:
Number of positive Predicted probability of joint sepsis
predictors
0
2.0%
1
9.5%
2
35.0%
3
72.8%
4
93.0%
Diagnosis is dif
/f_i
cult in neonates and the immunocompromised
Typical presentation is pain, fever and a reluctance to move
the joint or weight bear
Investigations should include FBC, ESR, CRP , blood cultures
and appropriate imaging studies, combined with astute clinical
skills
Pus in a joint destroys articular cartilage and causes avascular
necrosis of intra-articular epiphyses
Treatment is prompt removal of pus, appropriate antibiotic
therapy, pain relief and splintage

Septic arthritis

Joint infection is usually secondary to haematogenous spread but direct inoculation can occur, for example during a neonatal venepuncture. Diagnosis can be di ffi cult in the very young and in those presenting with overwhelming sepsis. Neonates, children with immunocompromise and those with sickle cell 

Figure 44.38
Anteroposterior pelvic radiograph of a child with spastic
cerebral palsy. The right hip is dislocated: none of the head lies medial
to the vertical
Perkins line. The acetabulum is dysplastic. The left hip
, knee
is in abduction. There is often a ‘windswept’ appearance with one leg
stiff in abduction and the other stiff in adduction. The red line demon
-
strates the pelvic obliquity; many children also have a
scoliosis. Note
the signi
/f_i
cant constipation; this can cause signi
/f_i
cant pain, which will
increase spasm and increase the pain still further.

the di ff erentiation between joint sepsis and transient synovitis of  the hip can also be di ffi cult. Classically , the child presents with pain, fever and a reluctance to move the joint; in the lower limb, this implies a reluctance to weight bear. On examination, local tender ness and painful restriction of  movement ar e apparent and in superficial joints inflammation may be obvious, with a hot, swollen joint. Investigations include FBC, ESR, CRP and blood cul tures. Plain radiographs help e xclude other diagnoses and may identify osteomyelitis. Ultrasound scans of  deep joints, such as the hip, will identify joint e ff usions ( Figure 44.39 ). MRI is considered the investigation of  choice b ut this resource is not available to all (in a timely manner) and, in young children, it requires a general anaesthetic. Good clinical skills, regu lar patient review and a high index of  suspicion are still the most valuable tools. Four clinical predictors can di ff erentiate between septic arthritis and transient synovitis ( Table 44.17 Pus in a joint is destructive: the proteases produced by leu kocytes destroy both the bacteria and the collagen matrix of the articular cartilage. A VN may occur secondary to pressure e ff ects or ischaemic infarction. The treatment of  a presumed septic arthritis therefore requires the prompt removal of pus from the joint and appropriate adequate antibiotic therapy . Pain relief  and rest are also important, as are the general health and nutrition of  the patient. The joint is aspirated and, if  pus is confirmed, a formal washout is mandatory; standard teaching states that the joint must be opened, irrigated and free drainage encouraged via the capsulotomy . Recent literature supports repeated aspiration/irrigation via a large-bore cannula or a small arthroscope for all joints except the hip. Antibiotic usage is guided by local hospital policy , the source of  the infection, the Gram stain and, in due course, the culture and sensitivity of  the organism identified. Joint instability , particularly in the hip joint ( Figure 44.40 ), may require the reduced joint to be splinted while the inflammatory process settles. /uni25CF /uni25CF /uni25CF /uni25CF Hans Christian Joachim Gram , 1853–1938, Professor of  Pharmacology (1891–1900) and of  Medicine (1900–1923), Copenhagen, Denmark, described this method of  staining bacteria in 1884. cus aureus . Streptococcal infection is also common and other organisms are more prevalent in certain age groups, e.g. the neonate, in certain conditions, e.g. sickle cell disease, or in cer - tain countries. The Haemophilus influenzae type B (Hib) vaccine - has essentially eliminated H. influenzae as a cause of  infection, but in some countries Kingella kingae has taken its place. Improvement is judged clinically and by monitoring the inflammatory markers. Reaccumulation of  pus does occur and - must be suspected and treated promptly if the child fails to improve. Summary box 44.21 Septic arthritis - /uni25CF /uni25CF ). /uni25CF - /uni25CF /uni25CF 

TABLE 44.17
Septic arthritis.
(a)
The clinical predictors of Kocher
et al
. (2004) for the diagnosis
of septic arthritis:
History of fever >38.5°C
Non-weight-bearing
Erythrocyte sedimentation rate >40
/uni00A0
mm/h
9
White cell count >12
/uni00A0×/uni00A0
10
/L
(b)
The value of the clinical predictors of Kocher
et al
. in
determining the likelihood of a joint being septic:
Number of positive Predicted probability of joint sepsis
predictors
0
2.0%
1
9.5%
2
35.0%
3
72.8%
4
93.0%
Diagnosis is dif
/f_i
cult in neonates and the immunocompromised
Typical presentation is pain, fever and a reluctance to move
the joint or weight bear
Investigations should include FBC, ESR, CRP , blood cultures
and appropriate imaging studies, combined with astute clinical
skills
Pus in a joint destroys articular cartilage and causes avascular
necrosis of intra-articular epiphyses
Treatment is prompt removal of pus, appropriate antibiotic
therapy, pain relief and splintage