Neuromuscular Diseases - Part 2 - Cartwright Flashcards
Muscle Disease can be __ or __.
___ muscle diseases affect children. It causes ____ and ___ weakness, without ___ involvement.
Children will have trouble going up/down stairs, or lifting arms above their head.
Muscular dystrophies – result from an __ in the ___ ____ (muscle cell membrane protein complex)
In Duchenne’s – __-___ recessive (affects ____), the dystrophin complex is ____.
These boys tend to have trouble walking at age __ (Gower’s), in a wheelchair by age __, death by age __-__. ____ (drug) seems to slows down disease progression by about 3 years.
Becker’s is similar to Duchenne’s but it is ___ severe, and a ___ progression. There are some dystrophin protein complexes in Beckers, but just very ___.
Muscle Diseases can be inherited or acquired
Inherited muscle diseases affect children. It causes symmetric and proximal weakness, without sensory involvement.
Children will have trouble going up/down stairs, or lifting arms above their head.
Muscular dystrophies – result from an abnormality in the dystrophin complex (muscle cell membrane protein complex)
In Duchenne’s – x-linked recessive (affects boys), the dystrophin complex is absent.
These boys tend to have trouble walking at age 2 (Gower’s), in a wheelchair by age 13, death by age 20-30. Prednisone (drug) seems to slows down disease progression by about 3 years.
Becker’s is similar to Duchenne’s but it is less severe, and a slower progression. There are some dystrophin protein complexes in Beckers, but just very little.
Muscle Disease can be inherited or acquired. In adults, inherited muscle diseases include:
___ ____ – most common adult-onset muscular dystrophy. It is often under-diagnosed. It is autosomal ___, a ___ repeat disorder, causes ___ weakness (___ weakness in hand), causes ____ (inability to relax muscle), also causes low ___, cataracts, diabetes and ___ conduction abnormalities.
•Other inherited muscle diseases include:
- other muscular dystrophies
Myopathies, which include ___, ___ and ___. Under ___, they can be a __ or ___ storage disorders. The one we talked about in class was which disease?
•Glycogen storage disease type II (Pompe’s) – can be treated with replacement of __ ___ ___.
Muscle Disease can be inherited or acquired. In adults, inherited muscle diseases include:
Myotonic Dystrophy – most common adult-onset muscular dystrophy. It is often under-diagnosed. It is autosomal dominant, a tri-nucleotide repeat disorder, causes distal weakness (distal weakness in hand), causes myotonia (inability to relax muscle), also causes low IQ, cataracts, diabetes and cardiac conduction abnormalities.
•Other inherited muscle diseases include:
- other muscular dystrophies
Myopathies, which include mitochondrial, metabolic and congenital. Under metabolic, they can be lipid or glycogen storage disorders. The one we talked about in class was which disease? Glycogen storage disease II –> Pompes
Glycogen storage disease type II (Pompe’s) – can be treated with replacement of alpha-acid glucosidase.
Under muscle diseases, acquired diseases include ____ myopathies.
Under this category, what four types of diseases are there?
- ___– muscle biopsy with many ___ ___ __, treated with ___
- _____ – often paraneoplastic, causes ___ rash, __ papules.
- __ __ __ – most common inflammatory myopathy, occurs over age ___, causes ___ ___ weakness, often doesn’t respond to ___
- ___ myopathies -
Under muscle diseases, acquired diseases include inflammatory myopathies.
Under this category, what three types of diseases are there?
- Polymyositis – muscle biopsy with many white blood cells, treated with prednisone
- Dermamyositis – often paraneoplastic, causes heliotrope rash, gottrens papules.
- Inclusion body myositis – most common inflammatory myopathy, occurs over age 50, causes finger flexion weakness, often doesn’t respond to treatment
Diagnosting Neuropathys:
By far, the most common cause of neuropathy is ____.
•Neuropathy: test for common and treatable etiologies of neuropathy:
- Glucose:
- ___ test (most commonly done)
- ___ or ___ blood sugar test
- __ hour glucose tolerance test - ___ deficiency
- Test for __ levels (see if they have hypothyroidism)
- ____: this is when the immune system is either in a malignant or pre-malignant state and is making things that affect the nerves. You can test for paraproteinemia using:
___ ___ ___ ___ or ___ ___ ___ ___
Diagnosting Neuropathys:
By far, the most common cause of neuropathy is diabetes
•Neuropathy: test for common and treatable etiologies of neuropathy:
- Glucose:
- HgB 1AC test (most commonly done)
- Fasting or random blood sugar test
- 2 hour glucose tolerance test - B12 deficiency
- Test for TSH levels (see if they have hypothyroidism)
- Paraproteinemia this is when the immune system is either in a malignant or pre-malignant state and is making things that affect the nerves. You can test for ____ using:
Serum protein Electrophoresis or Urine protein electrophoresis
How do you test for NMJ diseases?
__ ___ is much more common than Lambert-Eaton myasthenic syndrome, botulism, etc.
You can check for MG using what? This test is 80% sensitive and 95% specific for MG. They probably have MG (there are very rare cases that it is NOT MG).
If you find ___ receptor antibodies, then it probably means they have MG. This test is pretty rapid.
If you find __- ____ ___ receptor antibodies, then it probably means they have LEGS (lambert-eaton). This test takes several weeks
How do you test for NMJ diseases?
MG is much more common than Lambert-Eaton myasthenic syndrome, botulism, etc.
You can check for MG using what? –> Ach receptor antibodies.
This test is 80% sensitive and 95% specific for MG. They probably have MG (there are very rare cases that it is NOT MG).
If you find Acetycholine receptor antibodies, then it probably means they have MG. This test is pretty rapid.
If you find voltage-gated calcium receptor antibodies, then it probably means they have LEGS (lambert-eaton). This test takes several weeks
Your patient comes into your clinic, and they complain of proximal hypotonia, no sensory loss, cranial nerves are all intact, difficulty with coordination and gait, reflexes are intact, no mental loss. You suspect they have a ___ disease.
What type of blood test will you do for this disease?
You should always start by checking __ levels. This is the starting point for all suspected myopathies. A normal CK panel shows <200 as normal. If it is significantly elevated, they probably have a ___ disease.
Your patient has a CK level of 10,000. What do you suspect, and what do you do next?
-
Your patient has inflammatory myopathy. What kind of test will you run?
You will start with a CK test, and then do an __ ___ (ANA, DS DNA, __ panel, etc.)
Your patient comes into your clinic, and they complain of proximal hypotonia, no sensory loss, cranial nerves are all intact, difficulty with coordination and gait, reflexes are intact, no mental loss. You suspect they have a muscular disease.
What type of blood test will you do for this disease?
You should always start by checking CK levels. This is the starting point for all suspected myopathies. A normal CK panel shows <200 as normal. If it is significantly elevated, they probably have a muscle disease.
Your patient has a CK level of 10,000. What do you suspect, and what do you do next?
- we suspect muscular dystrophy. We should immeditely do a genetic test.
Your patient has inflammatory myopathy. What kind of test will you run?
You will start with a CK test, and then do an antibody test (ANA, DS DNA, myositis panel, etc.)
(EDX) Electrical Testing of Muscle Diease:
2 parts:
- NCS (Nerve conduction studies)
- EMG (electromyography)
1. NCS
In the NCS test, we are looking at ___ and ___.
_____: stimulates a nerve transcutaneously and measure the response from either a different segment of the same nerve (sensory testing) or a distal muscle (motor testing)
- The __ of the__ and the size of the ___ of the response are the key parameters in EDX testing.
- Nerves conduct electricity at about ___ m/s
Nerve conduction - stimulator shocks a nerve and records muscle potential, or a sensory potential. We then look at speed of conduction or amplitude. If someone has demyelinating neuropathy it will conduct slowly (slow velocity). If they have an axonal neuroapathy, the conduction is normal but the amplitude will be low.
2. EMG test
- EMG: a thin needle is inserted into muscle to record the ___ ___ of the muscle cells
- At rest, the muscle should be electrically ___. Diseased muscle (from either a primary nerve or muscle etiology) will result in muscle fibers that __ __.
- The patient is then asked to ___ the muscle, and the voluntary __ units are recorded
____ units = muscle disease
____ units = nerve disease and reinnervation
(EDX) Electrical Testing of Muscle Diease:
2 parts:
- NCS (Nerve conduction studies)
- EMG (electromyography)
1. NCS
In the NCS test, we are looking at conduction and amplitude.
NCS: stimulates a nerve transcutaneously and measure the response from either a different segment of the same nerve (sensory testing) or a distal muscle (motor testing)
- The speed of the conduction and the size of the amplitude of the response are the key parameters in EDX testing.
- Nerves conduct electricity at about 50 m/s
Nerve conduction - stimulator shocks a nerve and records muscle potential, or a sensory potential. We then look at speed of conduction or amplitude. If someone has demyelinating neuropathy it will conduct slowly (slow velocity). If they have an axonal neuroapathy, the conduction is normal but the amplitude will be low.
2. EMG test
- EMG: a thin needle is inserted into muscle to record the electrical potential of the muscle cells
- At rest, the muscle should be electrically silent. Diseased muscle (from either a primary nerve or muscle etiology) will result in muscle fibers that fire spontaneously.
- The patient is then asked to contract the muscle, and the voluntary motor units are recorded
small units = muscle disease (weakness)
large units = nerve disease and reinnervation (tall amplitude, wide spread)
NMJ testing
When we do nerve conduction studies, we can do repetive stimulation where we shock the nerve repeatedly.
- ___: slow (3 Hz) stimulation results in a decrement > 10% from baseline, usually a “J shaped” decrement curve
- ___: exercise or fast (50 Hz) stimulation results in an increment, usually > 200% above baseline
____: fast (50 Hz) stimulation results in an increment > 200% above baseline
NMJ testing
When we do nerve conduciton studies, we can do repetive stimulation where we shock the nerve repeatedly.
•MG: slow (3 Hz) stimulation results in a decrement > 10% from baseline, usually a “J shaped” decrement curve
•LEMS: exercise or fast (50 Hz) stimulation results in an increment, usually > 200% above baseline
Botulism: fast (50 Hz) stimulation results in an increment > 200% above baseline
Other ways to test the NMJ:
__ __: Edrophonium is a fast-acting acetylcholinesterase inhibitor. It prevents breakdown of the neurotransmitter acetylcholine. It is administered and almost immediately the clinical weakness improves.
https://www.youtube.com/watch?v=k7YX9kuWrxA&noredirect=1
Ice pack test: cold improves ptosis instantly due to neuromuscular junction transmission. Great thing to do in the ER in order to diagnose NMJ quickly.
Single fiber EMG: used to test MG. In MG there is increased jitter.
Tensilon test: Edrophonium, fast-acting acetylcholinesterase inhibitor, is administered and almost immediately the clinical weakness improves. https://www.youtube.com/watch?v=k7YX9kuWrxA&noredirect=1
Ice pack test: cold improves neuromuscular junction transmission
Single fiber EMG: special type of needle EMG, used to assess and compare the firing rates of two muscle fibers in a single motor unit, increased jitter is abnormal and is seen in MG.
Dog is wearing an endrophonium around his neck, when he plays tinsel flies out.
He is playing a single track called “my girl” and doing the jitter bug.
Antibodies tests:
In MG you can test three antibodies:
__
__
__
In LEMS you can test for:
____
Antibodies tests:
In MG you can test three antibodies:
ACH receptor antibody
MUSK
LRP4
Must look 4 AcH in MG.
In LEMS you can test for:
P/Q Voltage-gated calcium channel
Image Testing for Peripheral Nerves;
- Peripheral nervous system imaging __ behind the advances in CNS imaging over the past 3 decades
- MRI neurography and tractography can depict nerves, but are mainly research techniques
- Neuromuscular ___ can visualize small nerves and subtle muscle changes, and is now becoming a more common diagnostic test
Image Testing for Peripheral Nerves
- Peripheral nervous system imaging lags behind the advances in CNS imaging over the past 3 decades
- MRI neurography and tractography can depict nerves, but are mainly research techniques
- Neuromuscular ultrasound can visualize small nerves and subtle muscle changes, and is now becoming a more common diagnostic test
Myopathic findings
- ___ nuclei
- ___ atrophy
Neuropathic findings
- ___ ___ grouping
- ___ atrophy
Myopathic findings
- Central nuclei
- Rounded atrophy
Neuropathic findings
- Fiber type grouping
- Angular atrophy
What are you seeing here?
This is a myopathic (muscle disease) findings
- Central nuclei (remember, normally muscle nuclei should be peripheral)
- Rounded atrophic muscle fiber.
What is this?
Neuropathic findings (SMA, ALS)
- We see fiber type grouping. You get groups of Type 1 and Type 2 muscle fibers. It should normally be a checker board pattern, but here you see big blocks of Type 1 and big blocks fo Type 2.
- Angular atrophy
Plasmaphoresis
A. brachial plexus
A. This patient has a polyneuropathy. He has acquired, demyleinating, acute AIDP.
A. ALS
CK level
