Early diagnosis important in muscle disorder

Prompt diagnosis and treatment of dermatomyositis (JDM) in children is important, researchers report. Dermatomyositis is a rare inflammatory disorder in which the immune system attacks muscle and skin, often causing an extensive rash, as well as progressive, severe muscle weakness, pain, and fatigue.

Dr. Lauren M. Pachman, of Northwestern University, Chicago, and colleagues examined the effect of the duration of untreated symptoms in 166 children. The median duration of untreated disease - defined as the time from first sign of rash or weakness to the diagnostic visit with a doctor - was 4.04 months, they report in the Journal of Pediatrics.

The researchers discovered that boys and girls with untreated JDM were significantly shorter and lighter than the national norms. Growth impairment may be associated with JDM-related inflammation of blood vessels, which can lead to a marked decrease in the ability of the body to absorb food and nutrients, they suggest.

Pachman's team also observed a negative association between duration of untreated JDM and disease activity score for weakness. Non-white children were significantly weaker than white children and older children were more likely to have dysphagia (difficulty swallowing) and arthritis.

The duration of untreated disease is an important factor in fulfilling the criteria for JDM and should be considered in determining the intensity of therapy for these children, the investigators conclude.

SOURCE: Journal of Pediatrics February 2006.