Understand | diagnose | change

Whether you are looking to learn more about paediatric musculoskeletal problems, or are involved in the care of children, then PMM and PMM-Nursing will help you change your clinical practice for the better.

Swollen knee

Tom is a five year old boy who is referred with intermittent limp and fatigue. His parents have noticed that he cannot run as fast as he used to and was asking to be carried. He was generally well. pGALS demonstrates widespread joint abnormalities including muscle wasting, knock knees and hip contractures. He also has a small jaw and limited jaw opening. He has limited wrist movement (photograph below).

What is the diagnosis ?

Tom has polyarticular JIA.

He has widespread joint involvement and affecting more joints than were apparent from the parental observations.  The presence of muscle wasting, knock knees and small jaw (micrognathia) suggests chronicity and he is likely to have had arthritis for several months. Clues are often more obvious in retrospect but regression of achieved motor milestones is often commented on by parents. Sometimes children with an indolent presentation can lose considerable weight - the reasons include poor appetite, difficulty chewing and chronic ill-health. Other diagnoses including inflammatory bowel disease and malignancy must be considered. 

Investigations to establish the diagnosis will include blood tests, imaging and may take some time. 

  • Full blood count: A low haemoglobin, low white cell count or platelets should raise the possibility of haematological malignancy such as leukaemia; blood film and bone marrow aspirate may be required. An iron deficiency anaemia may suggest inflammatory bowel disease.
  • Elevated acute phase reactants (ESR or CRP) are unusual in polyarticular JIA. There is need to exclude infection (including reactive arthritis) and / or malignancy or inflammatory bowel disease.
  • A positive antinuclear antibody (ANA) in JIA is associated with an increased risk of uveitis. ANA is not diagnostic of JIA and can be observed in normal healthy children or with intercurrent illness. 
  • Rheumatoid factor (RF) is unlikely to be positive in JIA but if present then suggests a more guarded prognosis.
  • Prompt referral for eye screening is needed to check for chronic anterior uveitis, whether he is ANA positive or not. The highest risk is in the early stages of arthritis presentation. 
  • Varicella and measles serology: If non-immune, then vaccinations are advised if there is enough time before starting systemic immunosuppression with Methotrexate or Biologics - live vaccines are contraindicated whilst on such medications. Families need to know what to do if there is exposure to chicken pox or measles.
  • Plain radiograph: May show erosive disease in late presentations but usually radiographs will be normal. Radiographs are indicated with physical trauma or possibility of non-accidental injury.
  • Ultrasound scan (USS): useful to detect inflammation if the clinical examination is not clear.
  • Magnetic Resonance Imaging (MRI): useful to differentiate between damage and active synovitis or where joints are less accessible (such as hips, shoulders) or exclude other diagnoses (e.g., meniscal injury, tumour).
Key issues in the management ?

Impact of diagnosis upon Tom and his family

  • Provide disease information to improve understanding; signpost to resources (e.g., websites). 
  • Discuss role of specialist team - how and who to contact for advice.
  • Discuss how family will care for their child who may be unwell for a prolonged time. Family members may need to consider time off work to look after their child and see GP for a sick note if required. Specialist team may provide letter to employer if necessary.
  • Tom may require time off full-time school - educational needs should be considered and liaison with the school to discuss flexible timetable.

Explanation about disease process and management 

  • Encourage attendance for appointments including eye screening appointments and explain why review is necessary. Aim to rationalise appointments if possible to minimise disruption.
  • Need for immunosuppression over prolonged time and risk of infection, possible side effects and need for long term surveillance (Registries for Biologics).
  • Teach parents to assess child if unwell - check their child’s temperature and when to seek advice. 
  • When taking corticosteroids ensure advice given regarding not stopping steroids without discussion with specialist team. Give advice regarding contact with chicken pox and shingles and management.
  • Advice on vaccination schedules. Avoid live vaccines if on systemic immunosuppression.


  • Contact the extended multidisciplinary team - specialists, primary care, school health.
  • Liaise with school to improve understanding of condition, treatment and impact. “Do’s and Don’ts” for sport, school trips and activities. Input from physical therapists is important.

Symptom management 

  • Tiredness and fatigue; advice about pacing & building up stamina. Family may need support establishing bed times, sleep hygiene & appropriate rest. 
  • Regular pain relief and anti-inflammatory medication (non-steroid anti-inflammatory drugs NSAIDS) may help relieve joint pain.
  • Side effects of corticosteroids. Explanation of the need to achieve disease control whilst minimising side effects. Many side effects are reversible; particular support is needed for;
    • Weight gain - diet, exercise, consider dietician.  
Tom's Progress

Tom was admitted for intravenous methylprednisolone to help induce remission and started on methotrexate. He was discharged home on a tapering regime of oral corticosteroids. As an inpatient he met the MDT and also had his first eye screening appointment. He had physiotherapy as an outpatient to optimise joint range of movement and recovery of function. He and his family required ongoing education and support after his discharge and he was reviewed in the clinic to assess progress and have his blood tests taken after starting methotrexate. 

He had a marked improvement over the next six months in terms of his energy and mobility but had a further flare in his arthritis when the corticosteroids were tapered. He was started on a biologic therapy along with his methotrexate. 

Over the next 4 weeks his family observed that he was much happier in himself and at clinic review, he had much less joint swelling with improvement in range of joint movement. His muscle bulk slowly improved over the next 8 months. He was able to stop oral corticosteroids and remained on his regular biologic (Etanercept) given by subcutaneous injections twice a week along with methotrexate by weekly injection and folic acid.