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Flashcards in CM- Neuromuscular Disease Deck (62):

What are bulbar symptoms?

1. slurred speech
2. hoarseness
3. dysphonia- weak voice, inability to shout,sing, or raise the volume of one's voice
4. 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?

1. weakness
2. muscular atrophy and wasting
3. fasciculations
4. cramping


What are the UMN signs?

1. Babinski/Hoffman
2. spasticity [increased tone]
3. weakness
4. 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?

1. nerve conduction testing [motor v. sensory]
2. repetitive nerve stimulation [NMJ]
3. electromyography [muscle]


Describe what the following would be for an UMN lesion [brain or spinal cord]:
1. strength
2. DTR
3. Fasciculations
4. muscle mass
5. sensation

1. normal to hemiparesis
2. exaggerated, + babinski [extensor plantar]
3. no
4. normal
5. normal


Describe what the following would be for a lesion in the anterior horn:
1. strength
2. DTR
3. fasciculations
4. muscle mass
5. sensation

1. weakness
2. decreased
3. prominent
4. prominent [proximal]
5. normal


Describe what the following would be for a lesion in a peripheral nerve:
1. strength
2. DTR
3. fasciculations
4. muscle mass
5. sensation

1. weakness
2. decreased
3. possible fasciculations
4. distal atrophy
5. sensory loss


Describe the following for a lesion in the NMJ:
1. strength
2. DTR
3. faciculations
4. muscle mass
5. sensation

1. weak
2. normal
3. none
4. normal
5. normal

* Isolated weakness


Describe the following for a lesion in the muscle itself:
1. strength
2. DTR
3. fasciculations
4. muscle mass
5. sensation

1. weak [proximal]
2. normal
3. absent
4. proximal atrophy w distal pseudohypertrophy
5. 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?

1. myotonic dystophy
2. inclusion body myositis


What are the three tests that should be done if myopathy is suspected?

1. Electromyography
2. levels of CK and aldolase
3. antibodies associated with connective tissue disorders

[may also need biopsy]


What are the 4 broad categories for DDx of myopathy?

1. Inflammatory
2. muscular dystrophy
3. metabolic
4. 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
- 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?


1. clinical picture
2. elevated CK
3. EMG- small,short motor units with early recruitment
4. 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:
1. SLE
2. RA
3. 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?

1. HIV
2. Coxsackie
3. sarcoidosis
4. toxoplasmosis
5. influenza
6. 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?



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:
1. EMG
2. elevated CK, aldolase
3. muscle biopsy [shows degeneration, regeneration, phagocytosis of muscle fibers, fatty replacement & increased connective tissue]
4. blood testing for deletion of dystrophin gene

1. orthopedic tendon releases, motorized wheelchair
2. prednisone can increase strength but also increases weight


A patient presents with facial, neck and distal extremity weakness. She has the "hatchet face" appearance with ptosis, temporal wasting, a long face, and fish-shaped mouth.
What is the likely diagnosis?
What is the inheritance pattern?
What is the mutation? How does it manifest?
How is diagnosis made?

Myotonic dystrophy
-AD triplicate repeat of CTG on chromosome 19 which encodes a protein kinase leading to myotonia [inability to relax muscles after a sustained contraction]

Diagnosis is made with EMG, clinical presentation


What determines the clinical severity of myotonic dystrophy?

the number of triplicate repeats [CTG on 19]


What myopathy has associated findings such as:
- cataracts
- gonadal atrophy
- cardiac abnormalities
- endocrine dysfunction
-apathetic demeanor

myotonic dystophia [myotonia]


A 30 year old presents with mild, slowly progressive weakness of the face, shoulder girdle and proximal arm musculature.
The patient is unable to whistle, has scapular winging, and a foot drop.

Labs show normal to slightly elevated CK.

What is the likely diagnosis?
What is the inheritence pattern?

FSH dystrophy [facioscapulohumeral]
-autosomal dominant inheritence


A patient in his 50s presents with ocular motility defects, ptosis, and weakness in facial and cricopharyngeal muscles.
He has been experiencing severe dysphagia and is in need of a feeding tube.
What muscular dystophy is this presentation consistent with?
What ethnicity is it more common to occur in?
What is inheritence pattern?

Oculopharyngeal dystrophy
-French Canadians & Hispanics
- AD


What are the 3 main symptoms associated with a metabolic myopathy?
What are two main categories?

1, exercise intolerance
2. muscle cramping
3. myoglobinuria

Disorders can be of:
1. glycogen metabolism [McArdles]
2. lipid metabolism [carnitine palmitoyl transferase deficiency]


A patient presents with exercise intolerance, muscle cramping. Urinalysis shows increased levels of myoglobin.
You evaluate the patient with ischemic forearm exercise testing.
There is no increase in lactic acid.
What is the likely diagnosis

Metabolic myopathy of glycogen metabolism


A patient presents with retinitis pigmentosa, cardiac conduction defects, short stature, and seizures.
Serum and CSF lactic acid levels are elevated.

Biopsy reveals ragged red fibers.

What is the type of myopathy?
What are the 3 possible syndromes?

Mitochondrial myopathy

1. Kearns-Sayre syndrome - external ophthalmoplegia, retinitis pigmentosa, heart block

2. MELAS - mitochondrial encephalomyopathy, lactic acidosis, stroke

3. MERRF- myoclonic epilepsy and ragged red fibers


How is the diagnosis of mitochondrial myopathy made?

1. history and clinical findings
2. CK levels
3. EMG/NCV testing
4. muscle biopsy


What are the 2 major neuromuscular junction diseases?
What is the mechanism of each disease?

1. myasthenia gravis- immune mediated disorder with antibodies against the POST-SYNAPTIC AchR complex.

2. Lambert Eaton - antibodies block the voltage gated Ca channels on the PRE-SYNAPTIC side of the NMJ


A 30 year old woman presents with fatigue. She says it fluctuates throught the day but is usually less in the morning and gradually worsens as the day progresses.
She says it gets worse when getting out of chairs, blow drying her hair, or raising her hands. It improves with rest.
It bothers her most when her eyes get tired because they droop and she sees double. She also experiences difficulty swallowing.

There are no sensory effects, JUST weakness.

What is the likely diagnosis?
How is diagnosis made?


1. history/clinical
2. presence of AchR antibodies
3. EMG/NCV reveal decremental response on repetitive nerve stimulation

[CMAP progressively declines in amplitude in myasthenia gravis]


What is the purpose of the endrophonium chloride [Tensilon] test?

Confirms diagnosis of myasthenia gravis.

It is an Ach esterase inhibitor leaving more Ach in the NMJ. This should result in temporary restoration of muscle function


What are 4 possible disorders on the DDx for myasthenia gravis if the patient presents with ocular findings/signs?

1. mitochondrial myopathy- chronic progressive ophthalmoplegia
2. oculopharyngeal muscular dystophy
3. elevated ICP/ mass [pseudotumor cerebri]
4. senile ptosis


What are 4 possible DDx for myasthenia gravis if the patient presents with prominent bulbar symptoms [dysphagia, dysphonia]?

1. oculopharyngeal dystrophy
2. thyroid disorder
3. polymyositis
4. ALS, progressive bulbar palsy [PBP]


What are 4 possible DDx for myasthenia if the patient presents with generalized weakness?

1. LES
2. botulism
3. congenital myasthenia syndromes
4. myopathy/muscular dystophy [Duchenne's, Becker]


A patient presents with generalized weakness. He has an absent DTR, but it can be elicited after brief exercise. What is the suspected syndrome?
How does it differ from the other in its category?

1. weakness in LE> UE [MG is UE=LE]
2. never starts with ocular involvement
3. gets better with exercise
4. DTR is absent --> increased w/ exercise


What are the 2 most common forms of LES?
What should you do if the person presents with it?

LES can be:
1. paraneoplastic [small cell lung cancers]
2. autoimmune

If someone has a clinical presentation consistent with LES, do a CXR


Peripheral neuropathies can be broken down into axonal disorders and demyelinating disorders.
What are the syndromes associated with each?

1. diabetic neuropathy
2. EtOH

1. Gullain-Barre
2. chronic inflammatory demyelinating polyneuropathy


How do patients with peripheral neuropathies usually present?

1. first complaint is distal, symmetric sensory complaints that are length dependent [feet 1st, then hands about the same time as it reaches the knees]
-pain, numbness, loss of feeling, paresthesias [tingling/burning]

2. Next, there will be sensory AND motor findings
- ankle reflex is the first to become absent


What are the 2 most common causes of peripheral neuropathy in the US?
How do they present?

Diabetes- presents as distal, symmetric "stocking glove" neuropathy

Ethanol abuse is another common cause of peripheral neuropathy


How is the diagnosis of peripheral neuropathy made?

1. EMG/NCV - determines whether it is axonal or demyelinating

Based on the findings:
ESR, TSH, B12, Folate, RPR/VDRL, anti-DNA, ANA, glucose levels


A patient presents with ascending weakness that occurs over days to weeks. She reports back pain and paresthesia [tingling,burning].
On PE, you note decreased DTR.
What is the likely diagnosis and what is the cause?

Guillain-Barre Syndrome [GBS] - acute immune demyelinating polyneuropathy is a post-infectious, immune-mediated disease targeting gangliosides on peripheral nerves.

Infection with:
1. campy
2. CMV
3. HIV
Prior vaccine for: influenza, tetanus


How do you make the diagnosis of Guillain-Barre?

1. NCV - early nerve conduction will be slowed and later will indicate demyelinating damage
2. anti-GM1 antibodies [against peripheral gangliosides]


What is the cutoff between Guillain-Barre and chronic inflammatory demyelinating polyradiculoneuropathy?

GB is less than 4 weeks, CIDP is more


What are 2 most common neuropathies caused by trauma/compression?

1. median nerve --> carpal tunnel syndrome
2. lateral femoral cutaneous nerve - inguinal ligament meralgia paresthetica


A patient presents with paresthesia, pain and thenar atrophy. She is a receptionist and complains that it hurts when she types. What is the likely problem?
What is the cause?
What are predisposing factors?

Carpal tunnel syndrome- median nerve compression at the wrist.

Predisposing factors:
diabetes, pregnancy, repetitive mechanical stress, obesity, hypothyroidism


A patient presents with sensory loss in the lateral thigh. What nerve could be compressed?
What are predisposing factors to this condition?

Lateral femoral cutaneous nerve compression
1. obesity
2. pregnancy
3. tight clothes
4. utility belts


There are many neuropathies associated with systemic disorders.
Which are associated with:
1. endocrine disorders
2. connective tissue disorders
3. malnutrition

1. DM, thyroid disease
2. Sjogren's, RA
3. alcohol neuropathy


List the specific drugs that cause neuropathies that are:
1. antineoplastic
2. antimicrobial
3, antiviral
4. antiepileptic

1. vincristine, cisplatin
2. isoniazid
3. AZT and HIV drugs
4. dilantin [phenytoin]


How do motor neuron diseases present differently from myopathies in terms of age of presentation?

A lot of myopathies [specifically muscular dystophies] present early in life.

Motor neuron diseases usually present in adult life


Patients with ______________ present with both UMN and LMN symptoms.
___________ presents with LMN signs alone.
___________ presents with UMN signs alone.

Both = ALS [amyotrophic lateral sclerosis]

LMN = progressive muscular atrophy
UMN = primary lateral sclerosis


Describe the pathology of ALS.

degeneration or loss of motor neuron cells in:
1. cerebral cortex
2. brainstem motor nuclei
3. anterior horn cells


A 55 year old man presents with weakness, atrophy , fasciculations and cramping in his leg. He said it started in his calf and has spread to involve adjacent muscles. He demonstates a positive Babinski and Hoffman sign and has a spastic gait. His also demonstrates hyperreflexia and clonus.
Recently he has developed bulbar symptoms [slurred speech, dysphonia, dysphagia]. His wife says he has had extreme emotional lability and will spontaneously laugh or cry, often contradicting his mood.

What is the likely diagnosis?

1. LMN- fasciculations, weakness, atrophy
2. UMN - hyperreflexia, spascitiy, babinski

Bulbar symptoms
Pseudobulbar palsy- emotional lability


A patient presents with hyperreflexia, positive Babinski, and spasticity in his legs. He also is showing fasciculation in a particular cervical dermatome distribution. What are the 2 possible causes and how do you differentiate?

He has UMN signs in his legs and LMN signs at the involved level.

1. ALS
2. cervical spondylotic myelopathy - mid/high cervical compression lesion that can mimic ALS due to radiculopathy and nerve root compression

Differentate by:
1. MRI of cervical region


What is multifocal motor neuropathy with conduction block?
How is it differentiated from ALS?

MMN w/ conduction block is a treatable, immune mediated motor neuropathy with anti-GM1 titers and LMN signs only.


How can MG be confused with ALS?
What diagnostic tests distinguish them?

MG can have bulbar symptoms and weakness like ALS.

Distinguish between them with:
2. antibodies for AchR


How can MS be confused with ALS?
What diagnostic tests distinguish them?

MS can have a demyelinating plaque that involves ventral root exit causing LMN signs [usually MS is UMN].

Distinguish with:
1. cranial and spinal MRI
2. lumbar puncture


A patient presents with UMN findings, weight loss and fasciculations. She has heat intolerance, tremor, tachycardia.
The UMN and fasciculations [LMN] has you worried about ALS, however, what test should you run first before jumping to that conclusion?

TSH- because hyperthyroidism can be confused for ALS occasionally