Dermatomyositis

Estimated prevalence : 1/15,000 adults over 50 years of age : women are twice more frequently affected than men. Chronic inflammation of the connective tissue that affects certain areas of the skin (in general uncovered areas with photosensitivity) and some skeletal muscles, as well as a small vessel vasculitis. The term juvenile form (incidence: 2/106) is used when the disease starts between 5 and 14 years of age: this form, if diagnosed and treated early, has a better prognosis than the adult form. However, it can cause serious complications such as a pneumothorax (bubbles), a pneumomediastinum and hypoxic-ischemic-like neurological lesions  or hypertensive encephalopathy when on high dose corticosteroid therapy.

Dermatomyositis causes:

-        a purple (lilac) macular erythema on the upper eyelids ("heliotrope") or periorbital area,

-        a purple erythema on the extension face of the fingers and around the fingernails

-        myalgias with variable, usually proximal and symmetrical, muscular weakness

-        fever with altered general status

-        the presence of Gottrons papules (30 %): red, often scaly, bumps overlying the knuckles of the fingers

-        if the oropharyngeal muscles are affected: dysphagia, voice changes, aspiration

-   if the respiratory muscles are affected: dyspnea or respiratory failure. the involvement of the diaphragm is often paucisymptomatic or underestimated but it reduces the effectiveness of cough

-        the juvenile form is distinguished by the presence of a calcinosis (hard to the touch bumps under the skin, or sometimes in muscles), and sometimes a lipodystrophy

Sometimes:

-        arrhythmias: due to myocarditis or pericarditis

-        a Raynauds syndrome (10-15 %)

-        lung disease: either aspiration pneumonia in case of pharyngeal muscles involvement (15-20 %) or diffuse interstitial disease  (more frequent in case of anti-synthetase syndrome, see this term); severe pulmonary hypertension may appear

-        biliary cirrhosis

-        extension to the scalp: reddish and crusted plates with pruritus.

The diagnosis is made on the basis of the clinical picture, presence of very high CPK and LDH levels and muscle biopsy or MRI.

The clinical distinction between amyopathic dermatomyositis , dermatopolymyositis, and polymyositis depends on the presence or absence of skin and muscles involvement. From a pathological point of view, it seems that dermatomyositis is the result of a malfunction of the humoral immunity whereas polymyositis could rather be the result of dysfunction of cellular immunity.

Dermatomyositis may be associated with scleroderma, lupus erythematosus or Sjögren syndrome. In adults, it is sometimes a paraneoplastic syndrome: cancer of the breast, ovary, lung, colon.

A rare and special form of dermatomyositis is the Wong syndrome which combines typical lesions of dermatomyositis and areas of  psoriasiform cutaneous hyperplasia with parakeratosis in horizontal and vertical bands, follicular papules and palmoplantar keratoderma (pityriasis rubra pilaris) [MIM 173 200 for the familial form due to a mutation in the gene CARD14 on 17q25)].

Treatment: high-dose corticosteroids, sometimes immunosuppression or plasmapheresis.


Anesthetic implications:

check complete blood count and the CPK, ECG and echocardiography, respiratory function (+ RX or chest CT scan), the side effects of the treatment: corticosteroid replacement therapy; fragility of skin (dressings !). Monitoring of curarization: variable response to non-depolarizing myorelaxants due to the decrease in muscle mass, presence of inflammation; in case of acute myositis (high CPK) it is prudent to avoid succinylcholine.



References : 

-        Tillie-Leblond I, Colin G, Lelong J, Cadranel J. 
Atteintes pulmonaires des polymyosites et dermatomyosites. 
Rev Mal Respir 2006 ; 23 : 671-80.

-        Elst EF, Kamphuis SSM, Prakken BJ. 
Severe central nervous system involvement in Juvenile Dermatomyositis. 
J Rheumatol 2003 ; 30 : 2059-63.

-         Masaaki S, Bando T, Hasegawa S et al. 
Recurrent spontaneous pneumothoraces associated with juvenile polymyositis. 
Chest 2000; 118: 1509-11.

-         Haro R, Revelles JM, del carmen Farina M, Martin L, Requena L. 
Wong’s dermatomyositis: a new case and review of the literature. 
Int J Dermatol 2013; 52: 466-70.


Updated: August 2019