CM- Neuromuscular Disease Flashcards
What are bulbar symptoms?
- slurred speech
- hoarseness
- dysphonia- weak voice, inability to shout,sing, or raise the volume of one’s voice
- dysphagia- difficulty in swallowing
What is a fasciculation?
muscular twitching involving the simultaneous contraction of contiguous groups of muscle fibers
What are the 4 main LMN signs?
- weakness
- muscular atrophy and wasting
- fasciculations
- cramping
What are the UMN signs?
- Babinski/Hoffman
- spasticity [increased tone]
- weakness
- hyperreflexia and or clonus
__________ tend to affect proximal muscles, while _____________ affect distal muscles.
Myopathies affect proximal muscles, while peripheral neuropathies affect distal extremities
What are the 3 electrodiagnostic tests to determine which part of the neuromuscular unit is damaged?
- nerve conduction testing [motor v. sensory]
- repetitive nerve stimulation [NMJ]
- electromyography [muscle]
Describe what the following would be for an UMN lesion [brain or spinal cord]:
- strength
- DTR
- Fasciculations
- muscle mass
- sensation
- normal to hemiparesis
- exaggerated, + babinski [extensor plantar]
- no
- normal
- normal
Describe what the following would be for a lesion in the anterior horn:
- strength
- DTR
- fasciculations
- muscle mass
- sensation
- weakness
- decreased
- prominent
- prominent [proximal]
- normal
Describe what the following would be for a lesion in a peripheral nerve:
- strength
- DTR
- fasciculations
- muscle mass
- sensation
- weakness
- decreased
- possible fasciculations
- distal atrophy
- sensory loss
Describe the following for a lesion in the NMJ:
- strength
- DTR
- faciculations
- muscle mass
- sensation
- weak
- normal
- none
- normal
- normal
- Isolated weakness
Describe the following for a lesion in the muscle itself:
- strength
- DTR
- fasciculations
- muscle mass
- sensation
- weak [proximal]
- normal
- absent
- proximal atrophy w distal pseudohypertrophy
- normal
A person presents with symmetric proximal weakness. She is unable to rise from a chair, get off the floor or climb stairs. She gets tired combing her hair.
There is normal sensory function and reflexes.
What is the location of the lesion?
This is a lesion of the muscle [myopathy]
Most myopathies present with proximal weakness. What 2 myopathies are more likely to present with distal weakness?
- myotonic dystophy
2. inclusion body myositis
What are the three tests that should be done if myopathy is suspected?
- Electromyography
- levels of CK and aldolase
- antibodies associated with connective tissue disorders
[may also need biopsy]
What are the 4 broad categories for DDx of myopathy?
- Inflammatory
- muscular dystrophy
- metabolic
- mitochondrial
What age do inflammatory myopathies usually present?
Do they progress quickly or slowly?
Symmetric or asymmetric?
Distal or proximal?
Childhood or adult life
- slowly progressive
- symmetric
- proximal weakness
What muscles are spared by inflammatory myopathies?
Ocular muscles
A patient presents with slowly progressive, symmetric proximal weakness.
He has a heliotropic rash on his upper eyelids with periorbital edema, malar rash, and a rash over the knuckles [Gottron’s sign].
Labs show a very high CK level. What is it likely that this patient has? How is diagnosis made? What are they at increased risk for? What is treatment?
Dermatomyositis
Diagnosis:
- clinical picture
- elevated CK
- EMG- small,short motor units with early recruitment
- muscle biopsy
They are a 3-fold increased risk of cancer [lung, breast, ovarian, GI, myeloproliferative]
Treatment: immunosuppressants [azathioprine, methotrexate] ; IVIG for refractory cases
A patient presents with slowly progressive, symmetric proximal weakness. There is no fasciculations. DTR is normal/decreased.
The patient has elevated CK levels.
The patient has a positive ANA. What is the likely lesion?
Polymyositis is an inflammatory myopathy associated with:
- SLE
- RA
- scleroderma
An older patient presents with weakness of the proximal muscles with a predilection for:
- knee extensors
- distal involvement of finger flexors
The onset of weakness is symmetric and extremely gradual.
What is the likely problem?
How is its treatment different from other disorders in the same class?
Inclusion-body myositis
-differs from dermatomyositis and polymyositis because it is not effectively treated with immunosuppressants
What infections can cause inflammatory myopathies?
- HIV
- Coxsackie
- sarcoidosis
- toxoplasmosis
- influenza
- trichinella
A 5 year old presents with progressive hip and shoulder weakness. You follow his course and by the age of 12 he is in a wheelchair.
What is the likely disorder?
What is inheritence pattern?
What is the prognosis?
Duchenne’s muscular dystophy is an X-linked disorder.
Survival past the 3rd decade is rare due to respiratory failure or infection.
What myopathy can present with associated problems such as:
kyphosis, contracture, pseudohypertrophy of calves, cardiomyopathy, and mental retardation?
Duchenne’s
What is the cause of Becker’s and Duchenne’s muscular dystrophy?
How is diagnosis made?
What is treatment
Caused by a mutation in the dystrophin gene [dystrophin is a protein that connects the muscle fiber to the ECM to allow for contraction]
Diagnosis is by:
- EMG
- elevated CK, aldolase
- muscle biopsy [shows degeneration, regeneration, phagocytosis of muscle fibers, fatty replacement & increased connective tissue]
- blood testing for deletion of dystrophin gene
Treatment:
- orthopedic tendon releases, motorized wheelchair
- prednisone can increase strength but also increases weight