Idiopathic pain syndromes
Chronic idiopathic pain syndromes or Chronic Regional Pain Syndromes (CRPS) are mostly seen in older female children and adolescents; the pain can be incapacitating but the patient is otherwise well, and physical examination is usually normal.
Chronic idiopathic pain syndromes can be widespread or localized.
The widespread type may associate with fatigue and debility. The localised type most commonly affects the foot or hand, may be triggered by trauma (often mild) and can have characteristic features of the affected part being cool, cyanosed and very sensitive to touch (like reflex sympathetic dystrophy) - it is important to exclude vascular ischaemia. These children are often very debilitated and are missing school.
Management is multidisciplinary involving physiotherapy, pain management and psychology support. Outcome is variable.
It is important to exclude differential diagnoses including inflammatory / rheumatic disease, metabolic and endocrine disease, infection and malignancy. Careful clinical assessment is important.
Investigations to consider include:
- Full [complete] blood count (and film / peripheral smear) to help exclude malignancy or sepsis.
- Acute phase reactants (ESR, CRP, ferritin).
- Vitamin D and bone chemistry (consider rickets).
- Muscle enzymes (consider muscle disease).
- Thyroid function tests (consider hypothyroidism).
With localised forms of CRPS, bone scan may show diffuse asymmetrical blood flow.
