Dermatomyositis Flashcards
True or False
Patients with Juvenile dermatomyositis have an increased risk of malignancy
False.
They do however have an increased risk of calcinosis cutis and small vessel vasculitis
True or False
Dermatomyositis is more common in women than men
True
The F: M ration is approximately 2 - 3: 1
What are the subtypes of dermatomyositis?
Adult onset DM
- Classic
- Classic with malignancy
- Classic with AITCD overlap
- Amyopathic DM
Juvenile DM
- Classic
- Amyopathic DM
What are the cutaneous manifestations of dermatomyositis?
Heliotrope sign
Shawl sign
V neck sign
Holster sign
Gotrens papules
Gotrens sign
Poikiloderma
Non-specific:
- flagellate erythema
- erosions
- ulcerations
- alopecia
Nail changes
- cuticular dystrophy
- ‘ragged cuticles’
- hypertrophic cuticles
- nail fold telangectasia’s
- dilated capillary loops alternate with capillary drop out
Intensely pruritic (often much more so than SLE)
In Juvenile form:
- calcinosis cutis
What are the nail changes associated with dermatomyositis?
- cuticular dystrophy
- ‘ragged cuticles’
- hypertrophic cuticles
- nail fold telangectasia’s
- dilated capillary loops alternate with capillary drop out
Mechanics hands are associated with which form of dermatomyositis?
Patients with anti-synthetase syndrome
(anti-synthetase antibodies)
Which muscle groups are commonly affected by dermatomyositis?
Proximal extensor muscles
- triceps
- quads
Symmetrical
What are the non-cutaneous features seen in dermatomyositis?
Myositis
- symmetrical proximal muscle weakness
- dysphagia
- GORD
Pulmonary disease (15 - 30%)
- diffuse interstitial fibrosis (dry cough, progressive breathlessness)
Cardiac:
- Cardiac arrhythmia
- Conduction defects
Malignancy (15 - 25% risk)
- ovarian
- colon cancer
- nasopharyngeal cancer
- breast
- lung
- gastric
- pancreatic
- lymphoma
NB: malignancy risk returns to baseline after 3 years.
Which DM phenotype is high risk for pulmonary invovlement?
Anti-MDA5 DM
and
Anti-synthetase syndrome (anti- jo-1)
What are the characteristic features of anti-MDA-5 dermatomyositis?
Arthritis
Oral ulcerations
Severe non-scarring alopecia
Pulmonary disease
What are poor prognostic factors for dermatomyositis? (7)
Older age
Progressive disease
Initiation of therapy 24 months muscle weakness
Longer duration of symptoms prior to diagnosis
Pulmonary disease
Dysphagia
Extensive cutaneous involvement of the trunk
Which DM antibody has a high association with malignancy?
Anti - T1F1 - y
(also anti-NXP-2)
together thought to be responsible for 80% of malignancy
What are the risk factors for malignancy in patients with DM?
classic adult DM phenotype
Older age
Male
anti-T1f1-y antibodies
cutaneous ulceration
How should investigate someone with confirmed dermatomyositis?
Malignancy screen
- History including systems review
- Physical Exam
- Ensure up to date with age appropriate malignancy screens
- CT chest / abdo / pelvis
- transvaginal USS for women
Pulmonary function tests
What are the associations with DM?
Malignancy
Pulmonary disease (interstitial fibrosis)
Other AI -CTD (RA, systemic sclerosis, lupus)
What are the histological features of DM?
Lichenoid reaction pattern
Interface dermatitis
Vaculoalr alteration of basal keratinocytes
Pigment incontinence
Dermal mucin deposition
Sparse lymphocytic infiltrate
Epidermal atrophy
What do muscle biopsies show in DM?
type II muscle fibre atrophy, necrosis, regneration and hypertrophy
What is your DDx for a patient you suspect has DM?
Lupus
Psoriais
Allergic contact dermatitis
Photodrug eruption
Cutaneous T Cell lymphoma
Atopic dermatitis
How is amyopathic DM Treated?
Very challenging - and often treatment refractory.
General measures:
- photoprotection
- soap free wash
- moisturisers
Topical
- corticosteroids
- calcinurin inhibiotrs
Systemic
- HCQ (1st line)
- MTx
- MMF
- IVIG
- Rituximab
- Retinoids
- Apremilast
- Dapsone
- Thalidomides
What is the mainstay of treatment for myopathic DM?
Oral Corticosteroids
1mg /kg /day tapered 50% over 6 months and to zero over 2 -3 years
Second line / steroid sparing;
- MTx
- Azathioprine
- IVIG
- MMF
- Rituximab
- cylclosporin
- sirolmius
- TNF inhibitors (Caution as may exacerbate)
Investigations for a patient with DM ?
Bloods:
- ANA, ENA
- dsDNA
- Myositis antibodies
- C3 / C4
Histo:
- 3mm punch biopsy for histo and DIF
Evaluation for myositis (often guided by rheum)
- CK
- Electromyography
- USS
- MRI
- Muscle biopsy
Evaluation for associations
- PFTs
- CT chest / abdo / pelvis
- ECG
- consider barium swallow if symptomatic
Pre- treatment
- preimmunosuppression screen
- vit D
- C / M / P
- DEXA scan
Anti-M2 DM is associated with what phenotype?
Adult and juvenile DM, milder muscle disease,
good response to treatment
What is the clinical phenotype for anti- synthetase syndrome?
Myositis
Mechanics hands
Erosive Polyarthritis
Fever
Raynauds
Interstitial lung disease
Anti-t1f1 is associated with what clinical phenotype of DM?
Cancer ass. myositis in adult DM
Extensive cutaneous lesions
Palmer hyperkeratotic papules
Who gets DM?
Bimodal distrubution
- adults (peak onset 50)
- children (7 -10)
F >M (2 - 3 : 1)
