Muscle Disease Flashcards
What does “Myalgia” mean?
Muscle Pain
What does “My arms feel heavy and tired, i struggle to do things” imply about the muscle?
Muscle Weakness
What does “My muscle are stiff when i first wake up and then get a bit better when I’ve walked about for a bit” imply about the muscle?
Inflammation
Which muscle disease(s) have an increased risk of malignancy associated?
Myositis
especially dermatomyositis
What type of disease are Polymyositis and Dermatomyositis?
Idiopathic Inflammatory Myopathies
Autoimmune
Who’s more like to get polymyositis? (male/female) (ages 10-20/ 20-30/30-40/40-50/50-60/60-70/65+)
Females (2:1)
40-50 years peak
What is seen on biopsy of Polymyosits?
Muscle fibre necrosis
Degeneration
Regeneration
An inflammatory cell infiltrate
What is the most common presenting complaint of a patient with polymyosits?
Muscle weakness
List some clinical features of Myositis:
Muscle weakness
Insidious onset, worsening over months.
Usually symmetrical, proximal muscles
Mild myalgia in some patients (25-50%)
Was cutaneous signs are seen in dermatomyositis?
Gottron's sign (hands) Heliotrope rash (face/eyes) (purple/pink discoloration and swelling) Shawl Sign (Back)
Which drugs are known to cause proximal muscle weakness?
Steroids
What other presentations can be important to pick up in a history of tired muscles and functional difficulty?
Raynauds Phenomenon Weight loss Cough Breathlessness Dysphagia Fever Non-erosive Polyarthritis
What is the difference between Confrontational Testing and Isotonic Testing?
Confrontational = Direct testing of power (pushing) Isotonic = Repeated movement (e.g. 30 second sit to stand)
Which is a better test of muscle power? (Confrontational, Isotonic)
Isotonic testing
Why are Creatine Kinase enzymes raised in Myositis?
Muscle inflammtion and breakdown of muscle causes release of muscle enzymes during break down. Creatine Kinase is a muscle enzyme so levels of this rise (up into thousands) in myositis
What is a specific antibody of polymyositis and drmatomyositis?
Anti-Jo-1
What is an EMG?
Electromyography
Shows pattern of how muscle conducts electricity
What is seen on an EMG of a patient with polymyositis?
Increased fibrillations, abnormal motor potentials, complex repetitive discharges
Treatment for Myositis:
Prednisolone daily - decrease dose over time
Use immunosuppression at same time as steroid
(steroids - short term)
What is typical of Inclusion body myositis?
Distal muscle weakness
Weakness wrist and finger flexors in upper limbs and quadriceps and anterior tibial muscles in legs
Weakness often asymmetrical
Patients >50
CK levels lower than polymyositis
Muscle biopsy shows inclusion bodies
Responds poorly to therapy
How high are the CK levels in IBM and PM?
High
(Not up into thousands in IBM)
(Into thousands in PM, much higher)
What is the best test for myositis?
Biopsy
What are the main symptom of myositis?
Muscle Weakness
Which drugs may cause a presentation similar to myositis?
Statins