Nail and Distal Interphalangeal Joint in Psoriatic Arthritis

July 20, 2006

(First Release June 1 2006; J Rheumatol 2006;33:1315-9)

ABSTRACT.

Objective. To study distal interphalangeal (DIP) joints in patients with

psoriatic arthritis (PsA) with or without onychopathy, using magnetic

resonance imaging (MRI).

Methods. Twenty-three patients with PsA (9/14 F/M, median age 47 yrs), 12

with onychopathy (2/10 F/M, median age 44 yrs) and 11 without (7/4 F/M,

median age 52 yrs), and 10 control subjects (5/5 F/M, median age 43.2 yrs)

were enrolled. MRI of nail and distal phalanx (DP) including examination of

DIP joints was carried out. MRI was performed with a surface coil in a 1.5 T

device. For each selected finger, both longitudinal and axial scans were

performed. The involvement of nail, DP, and DIP joint was scored.

Results. Nail thickening with or without surface irregularity occurred in

95.7% of cases (100% with onychopathy and 90.9% without). MRI nail

involvement was more frequent in patients with clinical evidence of

onychopathy than in those without (p = 0.003). Similarly, 95.7% of patients

showed MRI abnormalities of DP (100% with onychopathy and 90.9% without).

MRI DP abnormalities were more marked in patients with clinical evidence of

onychopathy than in those without (p = 0.009). Involvement of DIP joints was

present in 34.8% of cases (58.3% with onychopathy and 9.1% without), and

onychopathic patients showed marked MRI DIP joint involvement in 5 cases and

mild in 2, while patients without onychopathy showed minimal changes in one

case (p = 0.03). Considering the entire group of patients, MRI involvement

of DIP joints was always associated with MRI DP changes, and in no case was

it present alone.

Conclusion. MRI nail involvement was present in almost all patients with PsA

studied, even in those without clinically evident onychopathy. MRI

involvement of DP always overlapped with nail involvement, since it was

present in all psoriatic cases showing MRI nail involvement. In contrast,

MRI DIP joint involvement was almost exclusively in a lower percentage of

the patients with clinical nail involvement and was always associated with

MRI DP changes. Our results suggest that DIP joint involvement is always

secondary to nail and DP involvement.

RAFFAELE SCARPA, ERNESTO SOSCIA, ROSARIO PELUSO, MARIANGELA ATTENO,

FRANCESCO MANGUSO, ANTONIO DEL PUENTE, ANGELO SPANÒ, CESARE SIRIGNANO,

ALFONSO ORIENTE, MATTEO NICOLA DARIO DI MINNO, SALVATORE IERVOLINO, and

MARCO SALVATORE

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