Complications

Complication
Timeframe
Likelihood
long term
high

May complicate long-term corticosteroid treatment.

The potential complications of long-term systemic corticosteroid use are numerous. These include osteoporosis, avascular necrosis of bone, glucose intolerance/diabetes mellitus, adrenal suppression, cataracts, hypertension, gastric ulceration, and weight gain.

Corticosteroid should be kept to the lowest possible dose for the shortest possible time. Appropriate use of corticosteroid-sparing agents can help minimise corticosteroid requirements.

long term
low

A rare complication of adult DM but occurs in 30% to 70% of patients with juvenile-onset DM.[68][69]

May be complicated by pain, joint contractures, and skin ulceration.

Aggressive early treatment of DM reduces the risk of calcinosis.[206] Other treatments may be of benefit including low-dose warfarin, high-dose diltiazem, aluminium hydroxide, alendronate, and probenecid.[207][208][209][210][211]

Surgical excision may be required in some patients.

long term
low

May complicate long-term use of hydroxychloroquine or chloroquine.

The risk of retinopathy is related to total cumulative drug exposure; therefore, the lowest possible dose should be used to control symptoms.

Adherence to prescribing and monitoring guidelines may reduce risk.[212][213]

variable
high

A significant cause of morbidity and mortality in these patients.

Respiratory muscle weakness, aspiration secondary to oesophageal involvement, and immunosuppression may contribute to increased risk of infection.[203][204][205]

variable
medium

Occurs in up to 40% of patients. Patients typically present with progressive dyspnoea and a dry cough.[76][100]

The histological pattern is not specific to DM and several patterns have been described.[200]

It is more common in patients with the anti-Jo1 antibody and may occur both in patients with classic DM and in those with amyopathic DM.[2][112][201]

Initial treatment is with systemic corticosteroids and, depending on response, immunosuppressants such as mycophenolate, azathioprine, ciclosporin, rituximab, or cyclophosphamide may be required.[99]

It may be difficult to differentiate between ILD and drug-induced pneumonitis in methotrexate-treated patients; therefore, methotrexate is relatively contraindicated in patients with ILD.[202]

variable
medium

Cardiac disease occurs in 50% of cases but is rarely symptomatic unless disease is advanced.

ECG and echocardiogram should be performed in all patients with DM.[79]

Conduction defects and atrial or ventricular dysrhythmias are the most common cardiac manifestations. Patients with symptoms of palpitations or syncope merit further assessment.[80]

Cardiac failure due to cardiac myositis is rare. Clinically apparent cardiac involvement is a poor prognostic indicator.[77]

variable
medium

May occur due to either oropharyngeal or oesophageal muscle weakness.

Dysphonia and nasal regurgitation may be associated symptoms. Assessment of swallowing by either video-fluoroscopic or barium studies is indicated in symptomatic patients.

variable
medium

Immunosuppression may result from the use of corticosteroids or other immunosuppressant agents and may complicate the course of these therapies.

Infections occur with both common and opportunistic pathogens.

The classic clinical features of sepsis may be absent in an immunosuppressed patient. A high index of suspicion is required to ensure timely intervention with antimicrobials.

variable
low

The incidence of malignancy in DM has been reported to be higher than in the general population.[4][195][196][197] Mortality ratio due to malignancy was 3.8 compared with the general population.[4] Rates of malignancy in DM range from 15% to 25%.[4][195][196][197]

Various malignancies have been reported in association with DM. The type of malignancy is usually appropriate to the age and sex of the patient, although gastrointestinal and ovarian tumours may be more common.[198][199]

Most cancers are diagnosed within the first 3 years of onset of DM.[4][197]

Screening should be performed at presentation and, if no malignancy is identified, annually for 3 years following diagnosis of DM.

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