CRITERIA FOR DIAGNOSIS OF POLYMYOSITIS AND DERMATOMYOSITIS

BOHAN ET AL NEJM 292:342-347 1975

MAJOR CRITERIA

1. SYMMETRICAL WEAKNESS OF LIMB GIRDLE MUSCLES AND ANTERIOR NECK FLEXORS, PROGRESSING OVER WEEKS OR MONTHS WITH OR WITHOUT DYSPHAGIA OR RESPIRATORY MUSCLE INVOLVEMENT.

2. MUSCLE BIOPSY EVIDENCE OF NECROSIS OF TYPE 1 AND 2 FIBRES, PHAGOCYTOSIS, REGENERATION WITH BASOPHILIA, LARGE VESICULAR SARCOLEMMAL NUCLEI AND PROMINENT NUCLEOLI, ATROPHY IN A PERIFASCIAL DISTRIBUTION, VARIATION IN FIBER SIZE AND ANY INFLAMMATORY EXUDATE, OFTEN PERIVASCULAR.

3. ELEVATED MUSCLE ENZYMES, ESPECIALLY CPK, ALDOLASE, LDH.

4. EMG TRIAD: SMALL POLYPHASIC ACTION POTENTIALS, POSITIVE SHARP WAVES AND INSERTIONAL IRRITABILITY AND BIZARRE HIGH FREQUENCY REPETITIVE DISCHARGES.

5. DERMATOLOGICAL COMPONENT: HELIOTROPE WITH PERIORBITAL OEDEMA. A SCALY DERMATITIS OVER DORSUM OF HANDS ESPECIALLY PIP'S (GOTTRONS SIGN), AND INVOLVEMENT OF KNEES, ELBOWS, MEDIAL MALLEOLI, FACE AND UPPER TORSO.

DEFINITE :

DERMATOMYOSITIS: 3 OR 4 CRITERIA PLUS THE RASH.

POLYMYOSITIS : 4 CRITERIA WITHOUT RASH.

PROBABLE :

DERMATOMYOSITIS: 2 CRITERIA PLUS THE RASH.

POLYMYOSITIS : 3 CRITERIA WITHOUT RASH.

POSSIBLE :

DERMATOMYOSITIS: 1 CRITERIA PLUS THE RASH.

POLYMYOSITIS : 2 CRITERIA WITHOUT THE RASH.

CLASSIFICATION.

GROUP

1. PRIMARY IDIOPATHIC POLYMYOSITIS.

2. PRIMARY IDIOPATHIC DERMATOMYOSITIS.

3. ASSOCIATION WITH NEOPLASM.

4. CHILDHOOD TYPE ASSOCIATED WITH VASCULITIS.

5. ASSOCIATION WITH COLLAGEN VASCULAR DISEASE.