POLYMYOSITIS AND DERMATOMYOSITIS (PM & DM)


Polymyositis is an inflammatory process affecting skeletal muscle.
Dermatomyositis is the same disease but with skin involvement.
Epidemiology



They are rare diseases with an incidence of 2-10 cases per million /year.
The onset is usually between 40 and 60 years of age.
The cause is unknown, although there is evidence for a genetic contribution.
Classification of Polymyositis / Dermatomyositis
Polymyositis
Adult
Pediatric
Inclusion-body myositis
Overlap (myositis associated with a connective tissue disease)
Dermatomyositis
With muscle weakness
Adult
Associated with cancer
Not associated with cancer
Pediatric
Without muscle weakness (amyopathic dermatomyositis or dermatomyositis sine
myositis)
Clinical features of polymyositis






Symmetrical proximal muscle weakness affecting the lower limbs more than the upper limbs.
Gradual onset.
Sometimes associated with muscle pain.
Systemic features of fever, weight loss and fatigue are common.
Respiratory or pharyngeal muscle involvement can lead to ventilator failure or aspiration.
Interstitial lung disease occurs in 30% of patients.
Clinical features of dermatomyositis


Presents similarly to PM but in combination with skin lesions.
Gottron's papules (scaly erythematous or violaceous psoriaform plaques occurring over
the extensor surfaces of proximal and distal IPJ's, elbows & knees.
 Gottron's sign: symmetric, nonscaling, violaceous Erythematous macules or plaques, often
atrophic, in the same distribution as Gottron's papules.
 Heliotrope rash (violaceous discoloration of the eyelid in combination with periorbital
edema.


Rash on the upper back, chest and shoulders (shawl distribution).
There is about a three-fold increased risk of malignancy in patients with DM & PM.
Systemic Manifestations and Complications of Polymyositis and Dermatomyositis
-----------------------------------------------------------------------------------------------------------------------Systemic manifestations
Common: proximal muscle weakness, dysphonia, dysphagia
Less common: respiratory muscle weakness, visual changes, abdominal pain
Systemic complications/associations
Cardiomyopathy
Cardiac conduction defects
Aspiration pneumonia secondary to respiratory muscle weakness
Diffuse interstitial pneumonitis/fibrosis
Large-bowel infarction secondary to vasculopathy has occurred in juvenile patients with
myositis
Muscle atrophy
Muscle calcification
Ocular complications including iritis, nystagmus, cotton-wool spots, optic atrophy, conjunctival
edema and pseudopolyposis
Internal malignancy
Investigations
---------------------------------------------------------------------------------------------------------------------------------Muscle enzyme elevation
Serum creatine phosphokinase (CPK), aldolase, ALT and LDH
Autoantibodies
ANA levels: elevated in 60 to 80 percent of patients with classic DM/PM
Antisynthetase antibodies
Jo-1: most common antisynthetase found; 20 percent of patients with DM may have positive
result
ESR: elevated in approximately 50 percent of patients, does not correlate well with disease
activity
Rheumatoid factor: elevated in 20 percent of patients, most often in those with overlap
syndromes
EMG: myopathic pattern, 10 percent are false-negative
Muscle biopsy: fiber necrosis, regeneration and inflammatory cell infiltrate
Screening for underlying malignancy (chest / abdomen / pelvis CT, gastrointestinal tract
imaging and mammography for women)
Treatment Modalities for Dermatomyositis
Treatment
modality
Oral prednisone
Dosage
0.5 to 1.5 mg per kg
Side effects
Gastrointestinal
Comments
Initial
daily until serum
symptoms, adrenal
pharmacologic
creatine kinase
suppression,
agent; consider
normalizes, then slowly immunosuppression,
adjunctive therapy if
taper over 12 months
avascular necrosis,
no improvement in
osteoporosis
objective muscle
strength after three
months of therapy.
Methotrexate
Oral: 7.5 to 10 mg per
Stomatitis, hepatic
First-line adjuvant
week, increased by 2.5
fibrosis, cirrhosis,
therapy in patients
mg per week to total of
nausea, abdominal
unresponsive to
25 mg per
pain, neutropenia,
steroids.
weekIntravenous: 10
thrombocytopenia,
mg per week, increased pruritus, fever,
by 2.5 mg per week to
pneumonitis, and
total of 0.5 to 0.8 mg
gastrointestinal
per kg Children: 1 mg
symptoms
per kg. As dosage
increases, taper off
steroid dose. Give 3 mg
daily of folic acid to
minimize side effects of
methotrexate.
Azathioprine
2 to 3 mg per kg per
Lymphoma, nausea,
day tapered to 1 mg per vomiting, hepatotoxicity,
kg per day once steroid leukopenia, oral ulcers,
is tapered to 15 mg per
thrombocytopenia
day. Reduce dosage
monthly by 25-mg
intervals. Maintenance
dosage is 50 mg per
day.
Cyclophosphamide Oral: 1 to 3 mg per kg
Increased risk for
In refractory cases
per dayIntravenous: 2
malignancy, leukopenia, only
to 4 mg per kg per day,
thrombocytopenia,
in conjunction with
hemorrhagic cystitis,
prednisone
anorexia, nausea,
vomiting, alopecia,
sterility, congestive
heart failure and
stomatitis
Treatment
modality
Mycophenolate
Dosage
2 g /day
Side effects
Bone marrow
Comments
suppression,
Mofetil
hepatotoxicity
Cyclosporine
2.5 to 10 mg per kg per
day*
Impairs T-cell
proliferation;
nephrotoxicity,
lymphoma,
hypertension,
hypertrichosis, gingival
hyperplasia,
hepatotoxicity,
paresthesias, fatigue,
hyperesthesias,
depression and
seizures
Hydroxychloroquine 200 mg twice daily in
Myopathy, differentiated Adjunctive
adults; 2 to 5 mg per kg by biopsy; hematologic
treatment to reduce
per day in children
rash
toxicity, hepatotoxicity,
antimalarial retinopathy,
dizziness, ataxia and
weight loss
Intravenous
2 g per kg in divided
Pancytopenia, death,
Showed
immunoglobulin
doses once per month
lymphoma
improvement in 70
for three months
percent of patients;
limited by high cost
Topical steroids
Physical therapy
Class I (super-high
—
For further control of
potency) or class II
the erythematous
(high potency) topical
and pruritic skin
steroid is recommended
changes
—
—
Directed at
preventing atrophy
andcontractures;
technique should
focus initially on
passive stretching
and splinting; more
aggressive strengthbuilding therapy
once inflammation
is controlled
Treatment
modality
Sun avoidance
Dosage
—
Side effects
—
Comments
Broad-spectrum
sunscreen,
protective clothing,
avoiding ultraviolet
light exposure
SJOGREN'S SYNDROME (SS)
Sjogren's syndrome is a chronic, slowly progressive, inflammatory autoimmune
disorder characterized by the infiltration of lymphocytes (T-cells in the majority of
cases), monocytes and plasma cells into the parotid (salivary) glands and lacrimal
(tear) glands. This chronic lymphocytic infiltration interferes with the normal
function of these glands and eventually results in a significant reduction or cessation
in the production and secretion of saliva and tears. The condition is named after
Henry Sjogren, an ophthalmologist, who first described the primary clinical features
of this disorder in 1933.
In approximately 40% of patients, Sjogren's syndrome progresses beyond the
exocrine glands and systemic (extraglandular) features develop.
Classification
Two distinct forms of Sjogren's syndrome have been recognized:

Primary Sjogren's syndrome - defined as dry eye and dry mouth that occurs by
itself and is not associated with another autoimmune disorder. Primary Sjogren's
syndrome occurs in approximately 50% of cases

Secondary Sjogren's syndrome - characterized by dry eye and dry mouth that
occurs in the presence of a major underlying autoimmune disease such as
rheumatoid arthritis, systemic lupus erythematosus, scleroderma, primary biliary
cirrhosis, chronic active hepatitis, or myasthenia gravis.
Epidemiology
The overall prevalence of Sjogren's syndrome in the general population has been
estimated to range from 0.5% to 3%. Sjogren's syndrome is a condition that affects
primarily women with a female to male ratio of about 9:1. Symptoms of the disorder
most often begin between the ages of 40-60.
Pathogenesis
The theories regarding the underlying causes of Sjogren's syndrome include:
o
Chronic inflammation
o
Cellular apoptosis (self-death of a cell)
o
Autonomic nervous system dysfunction
o
Neurotransmitter abnormality
o
Genetic predisposition (HLA-B8/DR3 association)
Clinical features

The classic signs and symptoms of Sjogren's syndrome affecting the oral cavity
(dry mouth, patients need water to swallow food) and the eyes (dry eye,
conjunctivitis, blepharitis and filamentary keratitis).

The signs and symptoms of Sjogren's syndrome that affects other areas of the
body, known as systemic or extraglandular features of Sjogren's, which may
include:
o
Salivary gland enlargement
o
Non-erosive arthritis
o
Raynaud's phenomenon
o
Fatigue
o
Low-grade fever
o
Interstitial lung disease
o
Cryoglobulinemia, Vasculitis
o
Peripheral neuropathy
o
Lymphadenopathy
o
Lymphoreticular lymphoma
o
Glomerulonephritis
o
Renal tubular acidosis
Investigations
- Anemia, leucopenia, thrombocytopenia
- High ESR, hypergammaglobulinemia
- Patients typically have a positive ANA, RF, anti SS-A (anti-Ro) and anti SS-B (anti-La)
antibodies.
- Special laboratory tests that are used to confirm the diagnosis of Sjogren's
syndrome that are designed to measure abnormalities in the production of saliva
and tears (Srmer tear test, Rose Bengal staining).
- Lip biopsy
Treatment
Currently there is no known cure for Sjogren's syndrome. The major goals of
treatment are to control the symptoms and prevent or limit the involvement of
other organs of the body.
The treatment options that are available to better manage the symptoms
associated with dry mouth, including:
o
Saliva substitutes
o
Saliva stimulants (sugar-free chewing gum or lozenges)
o
Good oral hygiene practices
o
Lifestyle modifications
The treatment options that are available to better manage dry eye symptoms,
including:
o
Artificial tears
o
Methylcellulose inserts
o
Eye ointments
o
Soft contact lenses
o
Muscarinic agonist drugs
o
Punctual occlusion surgery
The treatment options for the management of patients with Sjogren's
syndrome who manifest systemic or extraglandular involvement of other body
organs such as the skin, joints, lungs, kidney or nervous system.

Steroids
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Immunosuppressive drugs
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polymyositis and dermatomyositis (pm & dm)