Yuliarni Syafrita
Bagian Neurolog
FK Unand
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Polymyositis is an idiopathic inflammatory
myopathy
causes symmetrical, proximal muscle
weakness
elevated skeletal muscle enzyme levels
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General
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group of disorders
proximal muscle weakness
nonsuppurative inflammation skeletal muscle
prevalence
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5 cases/mil/year
2 to 1 F>M
40-60 yrs
pediatric variant 5-15-yrs
Epidemiology
 Idiopathic inflammatory myopathies are
relatively rare diseases.
 incidence in the United States that ranges
from 0.5-8.4 cases per million population.
 more common in the US within the black
population, with the estimated black-towhite incidences for polymyositis and
dermatomyositis being 5:1 and 3:1,
respectively.
 Internationally, polymyositis is less common
among Japanese persons.
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usually affects adults older than 20 years,
especially those aged 45-60 years.
Polymyositis rarely affects children.
observed in children, usually those aged 5-14
years
In most patients, polymyositis responds well
to treatment, although residual weakness
occurs in approximately 30% of patients
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usually present with symmetrical, proximal
muscle weakness in the upper and lower
extremities.
Patients with polymyositis may report muscle
pain and tenderness, which may be confused
with symptoms of polymyalgia rheumatica.
all of the muscles usually involved
Muscle weakness may fluctuate from week to
week or from month to month.
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Dysphagia secondary to oropharyngeal and
esophageal involvement occurs in about one
third of patients with polymyositis and is a
poor prognostic sign.
Facial and bulbar muscle weakness is
extremely rare in individuals with
polymyositis.
Etiology :
• Polymyositis is an immune-mediated
syndrome .
• secondary to defective cellular immunity
• commonly associated with other systemic
autoimmune diseases
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General
◦ criteria
proximal muscle weakness
elevated serum CPK
myopathic changes on EMG
muscle biopsy inflammation
definitive with four, probable with three, possible with
two
 dermatomyositis skin rash with above
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General
◦ labs
 anti-tRNA synthetases
◦ up to 20% associated with malignancy
 lung, ovary, breast, stomach
 parotid, tonsil reported
 dermatomyositis with nasopharyngeal carcinoma,
endemic areas
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Head and Neck Manifestations
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weakness neck muscles
difficulty phonation, deglutition, nasal regurgitation
dysphagia from upper esophagus
may result in aspiration pneumonia
Enzyme levels
Serum creatine kinase (CK) levels are usually
elevated in persons with polymyositis,
ranging from 5-50 times the reference range.
A level greater than 100 times the reference
level is rare and is a signal of other
diagnoses.
Other muscle enzymes that may be elevated
include the following:
 Lactic dehydrogenase
 Aspartate aminotransferase
 Alanine aminotransferase
 Aldolase - In practice, usually only the CK
and aldolase levels are determined
Electromyography
Electromyographic findings are abnormal in
almost all patients (90%) with polymyositis.
Various abnormalities consistent with
polymyositis may be found, depending on the
stage of disease
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Biopsy
Muscle biopsy is crucial in helping to
diagnose polymyositis and in excluding other
rare muscle diseases
Inflammatory changes are seen at muscle
biopsy (eg, deltoid or quadriceps femoris).
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Treatment
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steroids if symptomatic
methotrexate, immunosuppresives nonresponders
H2 blockers
metoclopromide
 Corticosteroids
 Prednisone
is the first-line treatment of
choice for polymyositis. Typically, the dose is
1 mg/kg/day, either as a single or divided
dose. This high dose is usually continued for
4-8 weeks, until the CK level returns to
reference ranges. Taper prednisone by 5-10
mg on a monthly basis until the lowest dose
that controls the disease is reached.
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Monitor response to therapy based on
improvement in muscle strength and muscle
endurance and decrease in CK levels.
Immunosuppressants
 Immunosuppressive agents are indicated in
patients who do not improve with steroids
within a reasonable period (ie, 4 wk) or in
whom adverse effects from corticosteroids
develop
 Patients with poor prognostic indicators, such
as dysphagia or dysphonia, are likely to
require immunosuppressive agents.
Other agents
 Intravenous immunoglobulin (IVIG) has been
used for the short-term treatment of steroidresistant cases of polymyositis.
 Diet
 Patients with polymyositis may benefit from a
high-protein diet. Monitor patients to avoid
excessive weight gain due to corticosteroid
use.
Activity
 During the acute stage of polymyositis,
patients may benefit from heat therapy,
passive range-of-motion exercises, and
splints to avoid contractures.
Etiologi :
 Pemakaian kortiko steroid
 Gangguan metabolik (hipoglikemi kronik,
myiglobinuria miopatik, penyakit penimbunan
glikogen)
 Gangguan endokrin (tirotoksikosis, sindroma
cushing, penyakit addison)