title: Nailfold videocapillaroscopy in healthy children and adolescents: description of normal patterns.
abstract: OBJECTIVE
  to describe normal patterns of nailfold videocapillaroscopy (NVC) in healthy children and adolescents; to quantify the relationship between age and capillary dimensions, intercapillary distance and number of capillaries/mm; to evaluate the inter and intraobserver concordance.
  
  
  METHODS
  Cross-sectional study including 100 healthy participants aged 5 to 18 years. Capillary dimensions (capillary loop length, capillary width and intercapillary distance) and number of capillaries/mm were evaluated in 900 capillaries using stereomicroscope under 100x magnification. Intra and inter observer agreements were tested.
  
  
  RESULTS
  The capillary dimensions (mean ± SD) were: capillary loop length 278.6±60.3 μm, intercapillary distance 124.1±28.1 μm, capillary width 15.0±2.6 μm. Teenagers between 15 and 18 years had longer and more enlarged capillaries than the other age groups (p<0.001 and p=0.012 respectively). We also found a significant increase in the number of capillaries/mm with age (p<0.001). There was a positive correlation between age and number of capillaries/mm, capillary length, and capillary width (p<0.001, R=0.796; p<0.001, R=0.368; p=0.004, R=0.285, respectively). There was a good intra and interobserver concordance. Enlarged capillary and avascular areas were present in 11% and 10% of capillaries respectively. A weak negative correlation was found between the intercapillary distance and the number of capillaries/mm (p=0.05; R=-0.20).
  
  
  CONCLUSIONS
  There is a wide variability in the capillary morphology among healthy individuals. There was a positive correlation between age and number of capillaries/mm, capillary length, and capillary width. In addition, NVC has been shown to be a reproducible method.
authors.affiliation: Division of Paediatric Rheumatology, Department of Paediatrics, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil.
authors.forename: Daniela P
authors.initials: DP
authors.lastname: Piotto
authors.affiliation: Division of Rheumatology, Department of Medicine, Universidade de Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Sekiyama
authors.affiliation: Division of Rheumatology, Department of Medicine, UNIFESP, Sao Paulo, SP, Brazil.
authors.forename: Cristiane
authors.initials: C
authors.lastname: Kayser
authors.affiliation: Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil.
authors.forename: Mariana
authors.initials: M
authors.lastname: Yamada
authors.affiliation: Division of Paediatric Rheumatology, Department of Paediatrics, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil.
authors.forename: Claudio A
authors.initials: CA
authors.lastname: Len
authors.affiliation: Division of Paediatric Rheumatology, Department of Paediatrics, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil. teterreri@terra.com.br.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Terreri
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002196:Capillaries / Q000033:anatomy & histology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D020678:Microscopic Angioscopy; D009262:Nails / Q000098:blood supply*; D015588:Observer Variation; D011237:Predictive Value of Tests; D012016:Reference Values; D015203:Reproducibility of Results