Primary care management and referral guidelines contain condition-based information for GPs about when to refer a patient, assessment and management measures that should be taken prior to submitting a referral, and what should be included in a referral to the relevant outpatient department or specialist service.
Osteomyelitis and septic arthritis:
- can affect any joint or bone, but most commonly involve the lower limbs.
- can occur in otherwise healthy children and are more common in children aged < 5 years.
- are bacterial infections usually arising haematogenously and can often follow trauma. Staphlococcus Aureus is the most common pathogen.
Classical presentation is with fever and limb or joint pain but can vary according to the age of the child, the site involved, and the virulence of the organism. Infants may present as septic or unwell without any localising signs.
Both osteomyelitis and septic arthritis require urgent assessment in hospital.
Consider infection until clinically excluded
If limb or joint is acutely swollen and/or painful, consider septic arthritis or osteomyelitis unless they can be clinically excluded.
Consider septic arthritis or osteomyelitis if child presents with:
- a limp.
- single, painful, or swollen limb.
- refusal to weight bear on either lower limb
- unable to move a limb normally (in infants who are not yet mobile).
- unwell with a fever, without a localising cause.
- localised erythema or swelling over a joint.
Look for other important features on history:
- Preceding trauma
A history of trauma should be considered carefully, as most children will have experienced some trauma, usually minor, in the recent past and it may or may not be responsible for the symptoms.
- Night waking with pain
Night waking with pain
Consider if night waking with pain is caused by growing pains, or septic arthritis or osteomyelitis.
- Growing pains occur at night, often after periods of activity during the day or evening, however the child will be well during the day without a limp. The pains are predominantly in lower limbs and are symmetrical. See Arthritis Australia – Growing Pains patient information sheet.
- With septic arthritis or osteomyelitis, pain will wake a child, but they will also have significant daytime pain that is likely to interfere with activities. There is no diurnal variation in inflammation of sepsis.
- Pain at rest
- Other painful, swollen joints
Examine the patient:
- Perform general examination:
- Look for signs of sepsis including fever, irritability or lethargy, and tachycardia.
Fever in bone and joint infections
- Fever is usually present in septic arthritis, which has a more acute onset.
- Absence of fever does not necessarily exclude septic arthritis in a child with a significantly irritable joint, particularly if they are taking intercurrent antibiotics or regular paracetamol for pain relief.
- Osteomyelitis often has a more subacute or insidious onset and fever may be absent, especially in neonates.
- Exclude generalised lymphadenopathy.
- Perform abdominal and inguinal examination.
- Look for rash.
- Check non-affected joints and limbs.
- Examine the affected joint or limb, looking for swelling, warmth, and tenderness.
- Compare sides and check both active and passive movement.
- Consider septic arthritis or osteomyelitis unless they can be clinically excluded. If infection is suspected, distinguishing between septic arthritis and osteomyelitis is not essential as both require orthopaedic intervention.
Distinguishing between septic arthritis and osteomyelitis
- Sub-acute onset of a limp or failure to weight‑bear or use limb
- Acute onset of symptoms – pain, failure to weight‑bear or use limb
|Acute onset of symptoms or pain
|Localised pain aggravated by movement
||Pain at rest and with movement
||Loss of range of or all movement
|Soft tissue redness, with or without swelling
||Soft tissue redness and swelling
Consider differential diagnoses for a limping or non-weight-bearing child.
- Developmental dysplasia of the hip
- Transient synovitis (irritable hip)
Transient synovitis (irritable hip)
- Most common cause of limp in young children – usually seen in children aged 3 to 8 years.
- Often follows a viral upper respiratory tract infection
- Child is generally systemically well and can walk but has a limp
- Usually associated with a mild decrease in internal rotation
- Non‑accidental injury or other trauma e.g., fracture, sprain, haematoma
- Perthes’ disease
- Avascular necrosis of the capital femoral epiphysis
- Most commonly seen in children aged 4 to 8 years
- 20% bilateral
- Restricted range of motion at the hip on examination
- Slipped upper femoral epiphysis in children aged > 10 years
Slipped upper femoral epiphysis
- Presents in late childhood or adolescence
- Often occurs in children with weight above the 90th centile
- Presents with limp as well as pain in the hip or knee
- On examination the hip appears externally rotated and shortened
- Decreased range of motion, especially internal rotation at the hip
- Can be bilateral
- Malignancy – acute lymphoblastic leukaemia, bone tumours
- Rheumatological disorders or reactive arthritis
- Overuse syndromes or stress fractures
- Intra-abdominal or inguinoscrotal disorders
- Functional limp
- If the child is unwell or there is any suspicion of septic arthritis or osteomyelitis, do not delay acute assessment by arranging investigations.
- Some features on X-ray or blood tests may help indicate the diagnosis.
X-ray and blood tests
- Blood tests will usually show an elevated WBC, CRP, or ESR but a normal result does not exclude bone or joint infection.
- X-rays are often ordered to rule out fracture, Perthes’ disease, or slipped upper femoral epiphysis. In septic arthritis or osteomyelitis they may be normal, but may show signs of a joint effusion (in septic arthritis), or bony erosion (a late sign of osteomyelitis).
- Joint ultrasound and diagnostic aspiration or other investigations will be done in hospital.
If septic arthritis or osteomyelitis are suspected:
- discuss with your local paediatric orthopaedic team or arrange transfer to your nearest ED as appropriate
- do not start oral antibiotics.
If diagnosis is uncertain and septic arthritis or osteomyelitis cannot be excluded, discuss with your local paediatric orthopaedic team
For a child with a painful joint or limb but low suspicion for ostemolyelitis or septic arthritis based on clinical findings:
- provide pain relief.
Pain relief can be achieved by:
- splinting or immobilising the joint with a sling or back slab.
- offering oral analgesia e.g., single dose of paracetamol 15 mg/kg (maximum 1 g), or ibuprofen 10 mg/kg (maximum 400 mg).
- review within 3 days. Discuss with your local paediatric orthopaedic team if persistent symptoms with unclear diagnosis.
- advise parents to seek urgent medical review with any deterioration e.g., fever, lethargy, worsening of pain, swelling, limp.
If suspected non accidental injury, ensure the child’s safety
Ensure the child’s safety
- Contact child safety services immediately and manage according to their advice.
- If signs of physical abuse (inflicted injury), or child at imminent risk of harm, consider transfer by ambulance to your nearest ED.
- Clearly document the event.
For health professionals
- BMJ Learning [requires registration] – Limp in Childhood: A Guide to Diagnosis and Management