In idiopathic polymyositis, following are seen except: (PGI May 2009)
|A||Ocular muscles are not involved|
|B||Pharyngeal muscles involved|
|D||Proximal limb muscles invariably involved|
1). In the question, as the patient is not able to comb her hair and is unable to climb up stairs it means she is suffering most likely with proximal myopathy. She also has skin lesion over the metacarpophalangeal joints, she probably has dermatomyositis & the skin lesion seem to be Gottron’s sign.
IDIOPATHIC INFLAMMATORY MYOPATHIES (Polymyositis & Dermatomyositis) (Ref. Hari-18th ed., pg- 3510)
1). Principal manifestation is muscle weakness
2). They affect persons of any age group, but the peak incidence is in the fifth and sixth decades of life.
3). Women are affected twice as commonly as men.
4). There is an increased risk of malignancy, (cancers of ovary, breast, melanoma, colon, non-Hodgkin lymphoma).
5). Rare patients with dermatomyositis have skin disease without overt muscle involvement, a condition termed “dermatomyositis sine myositis.”
Symptoms And Signs
1). Gradual and progressive muscle weakness. The weakness chiefly involves proximal muscle groups of the upper and lower extremities as well as the neck.
2). Dermatomyositis do not cause facial or ocular muscle weakness. (AIPG 2007)
3). In all forms of inflammatory myopathy, pharyngeal and neck-flexor muscles are often involved, causing dysphagia or difficulty in holding up the head (Ref. Hariead drop). In advanced and rarely in acute cases, respiratory muscles may also be affected. (Ref. Hari- 18th ed., pg- 3509)
4). Dermatomyositis involves the striated muscles of the upper pharynx and can make initiation of deglutition difficult.
5). In dermatomyositis skin signs as (AIIMS Nov 09)
6). Erythema also occurs over other areas of the face, neck, shoulders, and upper chest and back (“shawl sign”).
7). Periorbital edema and a purplish (Ref. Harieliotrope) suffusion over the eyelids are typical signs.
8). Scaly patches over the dorsum of PIP and MCP joints (Gottron's sign).
9). Mechanic’s hand
10. V sign – Rash over the neck area.
1). Raised muscle enzymes, creatine kinase and aldolase
2. Antinuclear antibodies are present in many patients,
3. Anti-Jo-1 antibodies, Anti synthetase antibody, Anti-signal recognition particles antibody.
Biopsy of clinically involved muscle is the only specific diagnostic test.
1). Most patients respond to corticosteroids.
2). Immunosuppressive Mycophenolate mofetil.
3). Since the rash of dermatomyositis is often photosensitive, patients should limit sun exposure.
The clinically suspected diagnosis of PM, DM, or IBM is confirmed by examining the serum muscle enzymes, EMG findings, and muscle biopsy.
1). ESR & RA factor would not directly help in establishing the diagnosis of inflammatory myopathy
2). EMG shows myopathic potentials characterized by short-duration, low-amplitude polyphasic units on voluntary activation and increased spontaneous activity with fibrillations, complex repetitive discharges, and positive sharp waves.
3). These EMG findings are not diagnostic of an inflammatory myopathy but are useful to identify the presence of active or chronic myopathy and to exclude neurogenic disorders.
4). Muscle biopsy is the definitive test for establishing the diagnosis of inflammatory myopathy and for excluding other neuromuscular diseases.
1). CPK level is normal in all endocrine myopathy except hypothyroid where it is increased. ( Ref. Hari-2693)
2). Inverted champagne bottle appearance is seen in peroneal muscle dystrophy.