dermatomyositis

CONSTANTIN HABERPGYI - SURGERY

Dermatomyositis

Background

Idiopathic inflammatory myopathy (IIM) with characteristic cutaneous findings.

Peter first suggested a set of criteria to aid in the diagnosis and classification of dermatomyositis and polymyositis (PM)

Progressive proximal symmetrical weakness Elevated levels of muscle enzymes Abnormal finding on electromyography Abnormal finding on muscle biopsy. Fifth criterion was compatible with cutaneous disease.

Background

Frequently affects the esophagus and lungs and, less commonly, the heart

Dermatomysitis and malignancy

Calcinosis is a complication of dermatomyositis

Observed most often in children and adolescents.

Pathophysiology

Pathogenesis of the cutaneous disease of dermatomyositis is poorly understood.

Bohan and Peter (1975) suggested 5 subsets of myositis:

Dermatomyositis Polymyositis Myositis with malignancy Childhood dermatomyositis/polymyositis Myositis overlapping with another collagen-vascular disorder.

Pathophysiology

In subsequent publications:

Bohan et al noted that cutaneous disease may precede the development of the myopathy.

Recognition of a new subset of patients with dermatomyositis that only affects the skin.

Amyopathic dermatomyositis [ADM] or dermatomyositis-sine myositis Lastly, another subset of patients with dermatomyositis have controlled myopathy but

continue to have severe and sometimes debilitating skin disease; this condition has been termed postmyopathic dermatomyositis

Pathophysiology

Studies on the pathogenesis of the myopathy have been controversial.

Some suggest that the myopathy in dermatomyositis and polymyositis is pathogenetically different.

Dermatomyositis is probably caused by complement-mediated (terminal attack complex) vascular inflammation

Polymyositis is caused by the direct cytotoxic effect of CD8+ lymphocytes on muscle.

Other studies of cytokines suggest that some of the inflammatory processes may be similar.

One report has linked tumor necrosis factor (TNF) abnormalities with dermatomyositis.

Frequency

The incidence of dermatomyositis/polymyositis has been estimated at 5.5 cases per million people, and the incidence is apparently

increasing.

Mortality/Morbidity

May cause death because of muscle weakness or cardiopulmonary involvement.

Patients with an associated malignancy may die of the malignancy.

Most patients with dermatomyositis survive, in which case they may develop residual weakness and disability.

Children with severe dermatomyositis may develop contractures.

Calcinosis may complicate dermatomyositis.

It is very rare in adults but is more common in children and has been linked to delay in diagnosis and to less-aggressive therapy.

Race/Sex/Age

No racial predilection

Twice as common in women as in men.

Occurs in people of any age.

Two peak ages of onset exist

In adults, the peak age of onset is approximately 50 years In children, the peak age is approximately 5-10 years.

Clinical History

Often present with skin disease as one of the initial manifestations.

As many as 40% of individuals with dermatomyositis, the skin disease is the sole manifestation at onset.

Muscle disease may occur concurrently, may precede the skin disease, or may follow the skin disease by weeks to years.

Individuals with dermatomyositis often notice an eruption on exposed surfaces.

The rash is often pruritic, and intense pruritus may disturb sleep patterns.

Patients may also report a scaly scalp or diffuse hair loss.

Clinical History

Muscle involvement manifests as proximal muscle weakness.

Affected patients often begin to note muscle fatigue or weakness when climbing stairs, walking, rising from a sitting position, combing their hair. or reaching for items in cabinets that are above their shoulders.

Muscle tenderness may occur but is not a regular feature of dermatomyositis.

Systemic manifestations may occur; therefore, the review of systems should assess for the presence of

Arthralgia Arthritis Dyspnea Dysphagia Arrhythmia Dysphonia.

Clinical History

Malignancy is possible in any patient with dermatomyositis but is more common in adults older than 60 years.

Only a few children with dermatomyositis and malignancy have been reported.

The history should include a thorough review of systems and an assessment for previous malignancy

Calcinosis is a complication of juvenile dermatomyositis but is rarely observed at disease onset.

Ask questions about hard nodules of the skin during the initial examination.

Physical Examination

Dermatomyositis is a disease that primarily affects the skin and the muscles but may affect other organ systems.

The characteristic, and possibly pathognomonic, cutaneous features of dermatomyositis include

Heliotrope rash Gottron papules. Malar erythema Poikiloderma in a photosensitive distribution Violaceous erythema on the extensor surfaces Periungual and cuticular changes are characteristic of dermatomyositis. even though

they are not pathognomonic.

Physical Examination

Muscle findings typically include

Proximal weakness. sometimes, tenderness Joint swelling Changes associated with Raynaud phenomenon Abnormal cardiopulmonary examination findings.

Physical Examination Heliotrope rash

Violaceous-to-dusky erythematous rash.

With or without edema in a symmetrical distribution

Involves periorbital skin.

Sometimes, this sign is subtle.

May involve only a mild discoloration along the eyelid margin.

Is rarely observed in other disorders. thus, its presence strongly suggests dermatomyositis.

Physical Examination Gottron papules

Found over bony prominences. Metacarpophalangeal joints Proximal interphalangeal joints Distal interphalangeal joints.

Papules may also be found overlying the elbows, knees, and/or feet.

The lesions consist of slightly elevated violaceous papules and plaques.

A slight scale and, occasionally, a thick psoriasiform scale may be present.

These lesions may resemble lesions of lupus erythematosus (LE), psoriasis, or lichen planus (LP).

Physical ExaminationNailfold Telangiectasia

Nailfold changes

Periungual telangiectases . Characteristic cuticular change with hypertrophy of the cuticle and small hemorrhagic

infarcts with this hypertrophic area. Periungual telangiectases may be apparent clinically or may be visible only on capillary

microscopy.

Poikiloderma may occur on exposed skin

May appear in a V-shaped distribution over the anterior neck and upper chest and back (ie, shawl sign).

Physical Examination

Physical Examination