Limp in a Child
This is an infrequent but alarming presentation, as it may herald significant pathology and may be difficult to manage properly in an uncooperative toddler. If within your scope of professional practice, assessment should be methodical and patient, and referral or follow-up arranged unless the diagnosis is obvious at the outset.
Differential diagnosis
Common Diagnoses
- Trauma, Including Foreign Body in Foot (Especially Toddlers)
- Irritable Hip (Transient Synovitis)
- Acute Viral Infection with Arthralgia
- Pauciarticular Juvenile Chronic Arthritis (JCA: 1 in 1000)
- Slipped Femoral Epiphysis (Usually Over 10 Years Old)
Occasional Diagnoses
- Perthes’s Disease (1 in 2000 between 4 and 10 Years Old)
- Septic Arthritis
- Idiopathic Scoliosis
- Congenital Dislocation of the Hip
- Acute Lower Abdominal Pain: Especially Appendicitis
- Unequal Leg Length
- Neurological (e.g. Cerebral Palsy)
Rare Diagnoses
- Acute Osteomyelitis
- Rheumatic Fever
- Autoimmune Disorders (e.g. SLE, Dermatomyositis)
- Rickets
- Genuine Juvenile Rheumatoid Arthritis
- Malignancy Affecting Bone
- Duchenne’s Muscular Dystrophy
Ready reckoner
Key distinguishing features of the most common diagnoses
| Trauma | Irritable Hip | Viral Infection | JCA | Slipped Epiphysis | |
|---|---|---|---|---|---|
| Fever | No | Possible | Yes | Possible | No |
| Sudden Onset | Yes | Possible | Possible | No | Yes |
| Stiff in Early Morning | No | No | No | Yes | No |
| Usually Over 10 Years Old | No | No | No | No | Yes |
| Many Joints Affected | No | No | Yes | Possible | No |
Possible investigations
Likely: FBC, ESR/CRP, X-ray.
Possible: Autoimmune screen.
Small Print: Calcium, phosphate, alkaline phosphatase, creatine kinase, ASO titre, blood culture.
- FBC and ESR/CRP: WCC and ESR/CRP elevated in an underlying inflammatory or infective cause.
- Hip X-ray: May reveal fracture, slipped femoral epiphysis, congenital dislocation, Perthes’s and other significant disorders – but may be normal in the presence of serious pathology.
- Rheumatoid factor and autoimmune screen may be helpful if a connective tissue disorder is suspected.
- Serum calcium, phosphate and alkaline phosphatase: Calcium and phosphate low, alkaline phosphatase high in rickets.
- Creatine kinase: Markedly elevated in muscular dystrophy.
- ASO titre is raised in 80% of cases of rheumatic fever.
- In hospital, blood culture may identify the infecting organism in osteomyelitis and septic arthritis.
Top Tips
- Never forget to examine the soles of the feet and between the toes for obvious and potentially simple to treat, non-serious causes of limp.
- It’s worth investing some time gaining the child’s confidence – this will enable you to make a proper assessment and feel positive about your management.
- Parents may try to rationalise the symptom by recalling a recent minor episode of trauma, which is likely to be purely coincidental.
- Don’t forget referred pain. Hip pathology can cause pain in the knee.
Red Flags
- Marked restriction of movement and/or dramatic bony tenderness suggests a significant problem – especially fracture, septic arthritis and osteomyelitis.
- Fever with a limp requires an urgent specialist opinion. Admit to exclude osteomyelitis or septic arthritis.
- Beware the obese pubertal boy with groin pain and a limp – slipped femoral epiphysis is likely.
- Do not confine your assessment to the hip – for example, abdominal pain, especially appendicitis, can make a child limp.