Nerve and Muscle Disease Flashcards by Andrew Hay

Describe the basic route for the movement of a muscle

Upper Motor Neuron
Anterior Horn Cell
Lower Motor Neuron
NMJ
ACh release
ACh receptor
Muscle stimulated

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What are these disorders, disorders of?

Muscle
Neuromuscular junction
Peripheral nerve
Anterior horn cell

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What is muscle?

An intricate machine designed to convert chemical energy to mechanical energy

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What are the components of the process for chemical energy -> mechanical energy

Excitation-contraction coupling

The contractile mechanism

Structural components

The energy system

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What is the presentation of muscle disease?

Weakness of skeletal muscle
Short of breath (respiratory muscle)
Cardiomyopathy
Poor suck/ feeding/ Failure To Thrive/ Floppy
Cramp, pain
Myoglobinuria
Wasting/ hypertrophy
Motor weakness… NOT sensory

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Explain why myoglobinuria occurs and what the results of it are

Muscles break down
Myglobin in blood
Filtered by kidneys
Makes urine look like coca cola

Large molecule so can clog kidneys up in large amounts -> renal failure

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How are muscle diseases classified?

Muscular dystrophies
Channelopathies
Metabolic muscle disease
Inflammatory Muscle disease
Congenital myopathies

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What parts can fail in muscle disease

Dystrophin
Actin
Sarcoglycan complex
Systroglycan complex
Laminin

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Name the muscular dystrophies

Duchenne's MD
Becker's MD
Facioscapulohumeral MD
Myotonic Dystrophy
Limb-Girdle MD

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What is Duchenne’s MD?

X linked
No functional muscular dystrophin produced

Poor motor milestones
(arent walking when young, wheelchair by teens)

Investigations:
CK, Genetics, Muscle biopsy

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What is Becker’s MD?

Allelic with DMD
Cardiomyopathy

Some dystrophin produced so less severe than DMD

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What is Facioscapulohumeral MD?

Autosomal dominant

Affects the skeletal muscles of the face, scapula and upper arms initially

Usually present in teens

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What is myotonic dystrophy?

Autosomal dominant trinucleotide repeat disorder

Multisystem disorder characterised by weakness and myotonia

myotonia = hard to relax muscles once contracted

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What is limb-girdle MD?

Large family of autosomal dominant and recessive disorders affecting primaryily the limb girdles

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What are channelopathies?

Disorders of Ca, Na and Cl channels

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How are channelopathies divided?

Periodic paralysis:

Familial hypokalemic periodic paralysis
Hyperkalemic periodic paralysis

Partial Paralysis:

Paramyotonia congenita
Myotonia congenita

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What is the difference between paramyotonia congenita and myotonia congenita?

Myotonia = the more you move the easier it gets

Paramyotonia = the more you move the harder it gets

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What is metabolic muscle disease?

Muscle isnt supplied very well with what it needs to function.

Muscle breakdown during exercise is therefore excessive

Myogobinuria can cause renal failure

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How can someone with metabolic muscle disease present?

Muscle pain (particularly after exercise) which is unusually excessive

Coca Cola urine

Renal failure

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How is metabolic muscle disease divided?

Disorders of carbohydrate metabolism

DIsorders of lipid metabolism

Mitochondrial myopathies/ cytopathies

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How can a patient get around disorders of carbohydrate metabolism?

Push through during exercise.

After 10-15 mins start to break down fat stores so will get “second wind”

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What will mitochondrial myopathies/ cytopathies effect?

Study These Flashcards

Many different systems, not just skeletal

What is Myositis?

Study These Flashcards

Inflammation of the muscles

What is Polymyositis?

Study These Flashcards

Inflammation of all the muscles

What is dermatomyositis?

Inflammation of muscles and skin Gives a characteristic rash

Describe inflammatory muscle disease

``` Acute or subacute Painful weak muscles Characteristic rash of DM Any age Other symptoms may be involved ```

What is the characteristic rash of dermatomyositis?

Gottron's sign = erythematous, scaly eruption occurring in symmetric fashion over the Metacarpal and interphalangeal joints (can mimic psoriasis). The heliotrope or "lilac" rash = eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swelling

What are the investigations for inflammatory muscle disease?

History and examination Increased CK EMG Biopsy - PM = CD8 cells - DM = humeral-mediated, B cells and CD4 cells Genetic testing (more common than biopsy nowadays)

What is the treatment for inflammatory muscle disease?

Immunosuppression

What is EMG?

Electromyography Evaluates and records the electrical activity produced by skeletal muscles. Can see if muscle is normal or abnormal Can see if the problem is msucle or nerve

Describe the function of the NMJ in normal patients

Ca mediated exocytosis of ACh Binds to ACh receptor Anticholinesterase breaksdown ACh so that muscle can relax

What happens to the NMJ in Myasthenia Gravis?

Autoantibodies block ACh receptors. Less receptors so ACh less effective Patients are fatiguable

What is the clinical presentation of Myasthenia Gravis?

Fatiguable Weakness: - Limbs - Eyelids (ptosis) - Muscles of mastication (chewing is tiring, may switch diet to easier foods) - Talking - SOB - Diplopia

What is the investigations into myasthenia gravis?

AChR antibody Anti MuSK antibody EMG Tensilon test CT chest

What is the tensilon test?

Nerve conduction of which you then look at the action potential In myasthenia gravis you do repetative stimulation and AP will get smaller and smaller

What is the treatment for Myasthenia gravis?

Symptomatic -Acetylcholinesterase inhibitor Immunosuppression: - Prednisolone - Steroid saving agent (azathioprine)

Explain myasthenia gravis and the thymus

Must check thymus in MG - In young associated with thymic hyperplasia - In old may be associated with a malignant thymoma ?Thymectomy -Females

What does peripheral nerve disease involve?

Lower motor neuron Sensory axons: - Small fibres (pain + temperature) - Large fibres (joint position sense + vibration) Motor axons

How is peripheral nerve disease divided?

Root disease Lesion of individual peripheral nerve Generalised peripheral neuropathy

What is Root nerve disease?

Degenerative spine disease Nerve root disorders are precipitated by acute or chronic pressure on a root in or adjacent to the spinal column. The most common cause is A herniated intervertebral disk (C5, 6, 7 or L5, S1) Bone changes due to RA or osteoarthritis, especially in the cervical and lumbar areas, may also compress isolated nerve roots. (outside of load bearing areas

What are the symptoms of root nerve disease?

Dermatomal sensory change Myotomal wasting and weakness Fasciculations

What is a lesion of an individual peripheral nerve?

Compressive/ entrapment neuropathy Vasculitis (mononeuritis multiplex)

What are the symptoms of a lesion of an individual peripheral nerve?

Specific sensory change Wasting and weakness of innervated muscle Fasciculations

What may generalised peripheral neuropathy involve? | What is it?

Motor/ sensory/ both +/- autonomic features Nerves start to die back from periphery

What are the causes of Generalised peripheral neuropathy?

Metabolic: DIABETES, ALCOHOL, B12 Toxic: drugs Infectious: HIV, leprosy, Lymes disease Malignancy: paraneoplastic Inflammatory demyelination - Acute: Guillain Barre syndrome - Chronic = CIDP

What does CIDP stand for?

Chronic inflammatory demyelinating polyneuropathy

What are the symptoms of general peripheral neuropathy?

sensory and motor symptoms starting distally and moving proximally

What are the investigations for nerve disease?

``` Blood tests Genetic analysis EMG Lumbar puncture (CSF analysis) Nerve biopsy ```

What does anterior horn disease affect?

Upper motor neurone in corticospinal or corticobulbar tracts Anterior horn cell

Describe Motor Neuron Disease (Amyotrophic Lateral Sclerosis)

Usually limb onset, later bulbar (muscles of mouth and throat) and respiratory involvement Combination of UMN and LMN signs -The more mixed the worse the prognosis M:F 3:2 Terrible prognosis

What lower motor neuron symptoms may you see in ALS?

Wasting weakness muscle fasciculations

What upper motor neuron symptoms may you see in ALS?

Pyramidal weakness Stiff Brisk reflexes

How do you diagnose Motor neuron disease?

Unique combination of UMN and LMN signs EMG

What is the treatment of ALS?

Supportive - counseling - multi diciplinary clinic riluzole

Nerve and Muscle Disease Flashcards

(54 cards)