Voluntary activation failure is detectable in some myositis patients with persisting quadriceps femoris weakness: an observational study

Table 1 Clinical and laboratory features of the 20 patients with idiopathic inflammatory myositis

Patient	Age/gender	IIM Subtype	IIM duration (yr)	Treatment	CK IU/l (24–170)	CRP IU/l (0–10)	MMT QF	EMG	MRI	Disease activity
1	35/M	PM/MCTD	8	P 5, Aza	60	9	5	ND	ND	Inactive
2	34/M	DM	0.5	P 30, SELAM	95	12	5	+	+	Active -
3	46/M	PM/CTD	6	P 20, MMF	109	40	5	ND	ND	Inactive
4	62/F	PM	1	P 7, SELAM	97	14	5	+	ND	Active -
5	59/F	PM	8	-	48	43	5	ND	ND	Inactive
6	62/F	DM	6	-	129	10	4+	ND	ND	Inactive
7	68/F	PM	1	Mtx	653	10	5	+	ND	Active -
8	40/F	DM	6	P 30, CyA, Mtx	486	11	4+	ND	ND	Active -
9	47/M	PM	12	P 10, Mtx	3,500	2	4-	+	+	Active +
10	67/F	PM/MCTD	10	P 10, Mtx	170	2	4+	ND	+	Active
11	58/F	PM/UCTD	1	P 7.5, SELAM	181	2	5	ND	ND	Active
12	50/F	PM	0.5	P 10, CyA, Aza	53	2	4	+	ND	Inactive
13	59/F	DM	7	P 7.5, Aza	144	6	5	ND	ND	Active -
14	66/F	PM	1	P 10, SELAM	159	2	4+	ND	ND	Active
15	43/F	PM/MCTD	3	P 30, CyA, Aza	305	1	4	ND	ND	Active -
16	41/F	PM	8	P 15	282	7	5	ND	+	Active -
17 *	49/F	PM	12	P 7.5	296	22	3-	ND	ND	Active
18	46/F	PM	6	P 30, MMF	3,331	31	3+	ND	ND	Active +
19 *	68/F	PM/MCTD	5	P 7, Mtx	83	8	4	ND	ND	Inactive
20	50/M	DM	10	Mtx	39	2	4+	ND	-	Inactive

CRP and CPK levels were current at the time of recruitment and are those used during disease activity and damage assessments. Extended MMT score is that for dominant QF. If EMG or MRI of QF had been performed within the previous 6 months, - or + indicates the absence or presence of inflammation, respectively. *Patients 17 and 19 had had muscle biopsies within the previous 6 months, and both showed end-stage disease with severe muscle atrophy and fatty and fibrosis replacement. Aza, azathioprine; CK, creatinine kinase; CRP, C-reactive protein; CyA, cyclosporin A; DM, dermatomyositis; EMG, electromyography; IIM, idiopathic inflammatory myositis; IU/l, international units per litre; MCTD, mixed connective tissue disease; MMF, mycophenolate mofetil; MMT, manual muscle testing; MRI, magnetic resonance imaging; Mtx, methotrexate; ND, (test) not done; P, prednisolone (daily dose, mg); PM, polymyositis; QF, quadriceps femoris; SELAM, patient participating in "SEcond Line Agents in Myositis" study, so on prednisolone plus Mtx or placebo and CyA or placebo; UCTD, undifferentiated connective tissue disease.

ISSN: 1478-6362