FRI0672 Assessment of the nail bed in psoriatic arthritis (PSA) by ultrasound (US) and MRI

Abstract

BackgroundPsA can be difficult to distinguish from osteoarthritis (OA) and the treatments vary greatly. Nail involvement can occur in about 15–50% patients with psoriasis1, which may aid differentiation from OA. If US can reliably detect nail bed changes in early disease then it might be helpful in differentiating PsA from OAObjectivesThis study aims to investigate the nail bed changes seen in patients with PsA and OA using US and MRI, and to determine the impact of nail bed changes on quality of life (QOL).MethodsPatients who fulfilled the CASPAR PsA or 1990 ACR OA classification criteria were recruited. At baseline, clinical assessment included patient and physician's visual analogue scale (VAS), tender and swollen joints, patient's Leeds Enthesitis Index and quality of life specific to nail psoriasis (NPQ10). Nail abnormalities on the dominant hand such as onycholysis, pitting, nail bed hyperkeratosis and nail bed crumbling were documented. Using US, each nail (1–5) was scored dichotomously for pitting/irregularity, loss of normal trilaminar appearance of the nail. Each nail was scored semi quantitatively for power doppler (PD) signal (0–3) in the nail bed, nail matrix and dermis, and assigned a total PD score. All patients had an MRI of the dominant 2nd to 5th finger.Results14 patients were recruited; demographics, clinical and US detected nail changes are documented in Table 1. Clinical nail changes were not seen in the OA group, but were relatively common in the PsA group. In the PsA group, 54% of nails had US detected structural abnormalities; 12% pitting and 52% loss of trilaminar layer. Only 20% of OA nails had US detected abnormalities. There was a strong relationship between the presence of clinical nail change and US structural changes (chi square 10.769 df 1 p=0.001) but not PD signal score. There was no relationship between clinical or US detected nail scores and NPQ10, patient or physician VAS, swollen joint count or Leeds Enthesitis Index. MRI analysis is pending.Table 1Total (n=14)PsA (n=10)OA (n=4) Age (median (IQR))56.5 (52.2–63.2)55.0 (48.0–63.2)61.0 (55.2–73.5)Patient VAS (median (IQR))29.0 (12.5–54.839.5 (19.8–54.8)11.0 (3.8–54.2)Physician VAS (median (IQR))35.3 (20.5–57.5)42.5 (24.5–57.5)24.0 (4.8–53.8)NPQ10 (median (IQR))6.5 (1.8–10.0)7.0 (5.2–10.2)1.5 (0.2–5.8)Swollen joint count (median (IQR))2.0 (0.0–4.2)1.5 (0.0–5.2)2.5 (0.5–5.8)Leeds Enthesitis index (median (IQR))1.0 (0.0–2.0)1.0 (0.0–2.0)0.5 (0.0–1.8)Percentage of nails with clinical abnormalities27.7%40.0%0.0%Percentage of nails with US structural abnormalities44.3%54.0%20.0%Percentage of nails with PD signal97.1%96.0%95.0%ConclusionsIn this small prospective study, structural abnormalities detected by US appear to correlate well against clinical structural findings, but PD signal does not. No relationship was found between US findings and other clinical parameters. US structural abnormalities may be a better differentiator of PsA and OA than PD signal. MRI validation of these results is pending.References Gisondi P, Idolazzi L, Gi...

The use of ultrasonography in the diagnosis of nail disease among patients with psoriasis and psoriatic arthritis: a systematic review

“…Study subjects were appropriately described in all included studies, and valid methods to determine the presence of the pathological condition were used and extensively described. The statistical analysis plan was deemed appropriate for the 15 studies [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. Overall, the risk of bias was assessed as moderate to high due to the small sample size of the studies.…”

“…Twelve studies reviewed gray-scale findings [26,[28][29][30][31][33][34][35][36][37][38][39]. Three of these studies were only pictorial essays, which were purely descriptive [41][42][43].…”

“…The normal nail plate was usually described as "two hyperechoic white bands surrounding an anechoic well defined layer in between" and the lack of visibility of the latter anechoic layer may technically be named using one of these definitions. Although it was impossible to compare studies in the absence of a uniform definition, there were consistently more nail lesions as measured using US in patients with PsA (46-54%) [29,35] ; p = 0.0410) [31]. US results have a good agreement with clinical assessment for nail disease (kappa value = 0.79 for PsA patients and controls; p < 0.001) [33] and also a strong correlation (chi-square test, 10.769 for PsA and osteoarthritis patients; p = 0.001) [29].…”

“…Although it was impossible to compare studies in the absence of a uniform definition, there were consistently more nail lesions as measured using US in patients with PsA (46-54%) [29,35] ; p = 0.0410) [31]. US results have a good agreement with clinical assessment for nail disease (kappa value = 0.79 for PsA patients and controls; p < 0.001) [33] and also a strong correlation (chi-square test, 10.769 for PsA and osteoarthritis patients; p = 0.001) [29]. However, it was not possible to confirm that US was more sensitive to detect nail disease versus clinical assessment.…”

“…Presence of vascularity within the nail unit by ultrasonography Nail bed PD signals were variable in both patients with PsO and PsA across the studies, with a range varying from 20 to 96% [27,29,30,35,44]. A high frequency of vascularisation was also observed in healthy controls, ranging from 20 to 81.6% [27,35].…”