Cutaneous blood flow in dermatomyositis and its association with disease severity

Association between nail-fold capillary findings and disease activity in dermatomyositis

OBJECTIVE

Although findings of nail-fold capillary changes and reduced red blood cell velocity in SSc patients are well established, studies in adult-onset DM patients are scarce. Our objective was to assess the changes and red blood cell velocity in finger nail-fold capillaries using nail-fold video capillaroscopy (NVC) in patients with adult-onset DM.

METHODS

This study included 50 patients with adult-onset DM and 20 healthy subjects. A semi-quantitative rating scale was used to score capillaroscopy changes. Red blood cell velocity was evaluated using frame-to-frame determination of the position of capillary plasma gaps.

RESULTS

Thirty-seven (74%) patients showed the scleroderma NVC pattern. Patients with the scleroderma pattern exhibited elevated serum creatine kinase levels more frequently and increased visual analogue scale of muscle disease activity. Scores of loss of capillaries were associated with muscle and global disease activity, whereas scores of haemorrhages were associated with skin disease activity. However, NVC findings were not significantly associated with lung involvement. The scores of irregularly enlarged capillaries, haemorrhages and loss of capillaries were reduced after stabilization of disease activity by treatment. The mean red blood cell velocity was not significantly reduced in DM patients compared with healthy controls and was not changed by treatment.

CONCLUSION

Our results suggest that changes in nail-fold capillaries reflect disease activity in DM. Furthermore, the differences found in red blood cell velocity may reflect somewhat distinct microcirculation injuries in DM and SSc.

Nailfold capillary microscopy in adults with inflammatory myopathy

OBJECTIVES

To study the presence and characteristics of nailfold capillary changes in a cohort of adult patients with inflammatory myopathies, determine correlations with disease activity and severity, and investigate any relationship between capillary findings and the immunological or clinical characteristics of the groups.

METHODS

Fifty-three consecutive adult patients followed in our outpatient clinic were evaluated using a Wild M3 stereomicroscope with an Intralux 5000 Volpi cold light lamp. A semiquantitative rating scale was used to score capillaroscopy changes. Disease activity and severity were assessed with the Myositis Disease Activity Assessment Tool and Myositis Damage Index, respectively. Associations between capillaroscopy findings and other factors were calculated with the chi(2) and Mann-Whitney U tests. Serum autoantibody profile was determined in all patients.

RESULTS

Twenty-three patients (43%) showed relevant capillaroscopy changes. No significant association was observed between the number of capillaroscopy alterations and the clinical or immunological groups, or disease duration. Disease activity and severity were both significantly associated with a larger number of capillaroscopy findings (P < 0.05). The combination of microhemorrhages and capillary enlargement was significantly more frequent in patients with dermatomyositis (OR, 8.9; 95% CI, 1.8-45.2), and a characteristic capillaroscopy pattern was associated with paraneoplastic myositis (OR, 14.7; 95% CI, 2.0-106.4). Interstitial lung disease significantly correlated with higher capillary score (OR, 3.7; 95% CI, 1.1-13.0).

CONCLUSIONS

Nailfold microcirculation as determined by semiquantitative simple capillaroscopy appears to provide useful information in patients with idiopathic inflammatory myopathy, contributing to an early diagnosis and identifying patients with a poor prognosis.