Pitfalls

Limp is a symptom and not a diagnosis

There are red flag conditions not to be missed.  The causes can be broadly divided into acute and chronic and are categorised by age.

Common pitfalls in making a diagnosis of limp include:

• Ascribing limp to trauma and overlooking features that suggest other causes.
• Referred pain (e.g., from the abdomen [and testes in boys], back or chest and hip pathology manifesting as knee pain).
• Think beyond the hip (!) and examine the child comprehensively.
• Assess for proximal muscle weakness; ask the child to get up from the floor (Gower's manoeuvre), jump or climb a step.
• Classical clinical features of sepsis may be masked in the immunosuppressed child.
• Mycobacterial infection can be easily missed.
• Synovial fluid may be sterile in partially treated septic arthritis.
• Labelling children with daytime symptoms as having “growing pains”.
• Medically unexplained limp or physical symptoms warrant specific management and referral (i.e., discharge without a diagnosis and follow up plan is not advised).
• The blood film may be normal in children with malignancy.
• Radiographs are often normal in children with early sepsis or arthritis.
• Acute phase reactants may be normal in children with inflammatory arthritis.
• Rheumatoid factor is usually negative in children with inflammatory arthritis.
• Antinuclear antibody and rheumatoid factor may be false positive in children without inflammatory joint or muscle disease.

 Further information about limp is available. 

https://www.rch.org.au/clinicalguide/guideline_index/Child_with_limp/