Neuropathies Flashcards
Define neuropathy (2)
- Disease or dysfunction of one or more of the peripheral nerves
- Typically causes numbness or weakness
What are peripheral nerves?
- These nerves send messages from the central nervous system, the brain and the spinal cord to the rest of the body
Give 3 types of neuropathy
- Charcot-Marie-Tooth disease
- Guillian-Barre syndrome
- Myasethenia gravis
Describe Charcot-Marie-Tooth disease (4)
- Group of hereditary neuropathy disorders affecting peripheral nerves
- Muscles of lower legs become weak and waste away
- Over 40 types
- Motor and sensory neuropathy
What is the prevalence of Charcot-Marie-Tooth disease?
1/2,500
When is the onset of Charcot-Marie-Tooth disease?
- Symptoms usually begin between 5-15 years, sometimes middle age or later
How is Charcot-Marie-Tooth disease classified?
- Based on the damage caused:
Demyelination
Damage to the axon
What is the aetiology of Charcot-Marie-Tooth disease?
Inherited fault in one of the many genes responsible for development of the peripheral nerves
What is the inheritance pattern of Charcot-Marie-Tooth disease? (2)
- Most inherited in autosomal dominant trait (only one gene from one parent required)
- Chances of passing on to offspring depends on the specific genetic faults carried
What are 6 symptoms of Charcot-Marie-Tooth disease?
- Muscle weakness
- Awkward or ‘slapping’ gait
- Highly arched or very flat feet, hammer toes
- Numbness in feet, arms and hands
- Weakness begins in lower legs
- Later hand muscles begin to waste away
Where does muscle weakness occur in Charcot-Marie-Tooth disease? (5)
Feet, ankles, legs, hips and hands
What is a slapping gait?
Feet hit the floor hard whilst walking
How does the weakness in lower legs progress? (3)
- Weakness begins in lower legs
- Causes an inability to flew the ankle to life the front part of the foot (foot drop)
- Wasting away of calf muscles (stork leg deformity)
Give a summary of the diagnosis of Charcot-Marie-Tooth disease
- Electromyography and nerve conduction studies
- Physical evaluation
- Genetic counselling
What does the physical examination of Charcot-Marie-Tooth disease involve? (3)
- Which areas are weak
- Onset of symptoms
- Family history
What is the prognosis of Charcot-Marie-Tooth disease? (5)
- No cure
- Progresses slowly and does not affect life span
- Differs in severity
- Can make everyday activities difficult
- May have significant emotional impact
What may be the symptoms of mild Charcot-Marie-Tooth disease?
High arches and hammer toes may be the only symptoms
Summarise the treatment of Charcot-Marie-Tooth disease
- Physiotherapy
- Occupational therapy
- Braces and other orthopaedic devices
- Pain medication
- Orthopedic surgery
What is Guillain-Barre syndrome? (2)
- Rare, short term but potentially life threatning disorder affecting the nerves in the body
- Immune system attacks part of the peripheral system so signals cannot be sent from the brain to the muscles as quickly as they should
What does Guillain-Barre syndrome cause?
Muscle weakness which worsens over a few days to weeks
When does Guillain-Barre syndrome occur? (2)
- Can occur at any age, but especially common in people older than 50 years
- Most children recover fully with no complications
Outline the aetiology of Guillain-Barre syndrome (4)
- Exact cause is unknown
- Few days or weeks after viral infection
- Rare cases: may run in families
- Vaccinations, certain medications and surgical procedures
Give 4 types of viral infections which may be linked to Guillain-Barre syndrome
- Cytomegalovirus
- Epstein-Barr virus
- Flu
- Zika
Give a type of bacterial infection which is linked to Guillain-Barre syndrome
Campylobacter jejuni
Outline the inheritance patterns of Guillain-Barre syndrome (3)
- Mutations in a particular gene are not known to be associated with GBS
- Not thought to be passed directly from parent to child
- In rare cases, multiple people in one family have GBS
Is there a genetic component of Guillain-Barre syndrome?
Family members may share normal variants in certain genes which may increase the risk of GBS
How long do the symptoms of Guillain-Barre syndrome continue to worsen for?
Worsen over first 2-3 weeks
What are 10 symptoms of Guillain-Barre syndrome?
- Muscle weakness, pain and short term paralysis of face, chest, leg and pharynx muscles
- Breathing problems, choking and aspiration
- Decreased sensation in fingers and toes
- Leg weakness
- Leg pain that moves to arms
- Problems with walking
- Irritability
- Dysphagia
- Facial weakness eg. facial droop
- Vision changes
What 2 symptoms can impact vision in Guillain-Barre syndrome?
- Double vision
2. Changes in eye movements
What are 3 other symptoms of Guillain-Barre syndrome?
- Difficulty with bladder/bowel function
- Blood pressure
- Heart rate
Summarise how Guillain-Barre syndrome is diagnosed (5)
- Physical exam: symptoms and history
- Blood tests and urine tests
- Lumbar puncture
- Electromyogram (EMG)
- Pulmonary function test
What symptoms are investigated during the physical exam of Guillain-Barre syndrome?
- Muscle weakness on both sides of the body that starts from lower leg muscles and spreads upwards
- Relatively rapid progression and loss of muscle reflexes
Why is a lumbar puncture conducted in Guillain-Barre syndrome?
People with GBS have high levels of protein in the CSF
Why is an EMG carried out in Guillain-Barre syndrome?
Determine if the muscles are responding to signals correctly and nerve conduction studies measure speed of signals
What is the prognosis of Guillain-Barre syndrome? (5)
- Speed of recovery depends on severity of nerve damage
- Can occassionally be life-threatening and some are left with long term problems
- Often treated in ICU
- Some may relapse after an original improvement in symptomms
- Depression and anxiety
When is recovery expected in Guillain-Barre syndrome? (2)
- Symptoms can last up 1-2 months
2. Full recovery is at least 1-2 years after diagnosis
What percentage of people of GBS continue to have muscle weakness years after the first symptoms?
30%
What can be the causes of death in Guillain-Barre syndrome? (4)
- Acute respiratory distress syndrome
- Sepsis
- Pulmonary emboli
- Cardiac arrest
What can be a consequence if GBS is not treated?
Paralysis of the chest muscles leading to respiratory problems and death
Summarise the treatment of Guillain-Barre syndrome (6)
- Depends on symptoms, age, severity and general health
- Early management is crucial
- Intravenous immunoglobulin (IVIG)
- Plasma exchange (plasmapheresis)
- Supportive care
- Symptom reduction
What is plasmapheresis? (3)
- Removes plasma from the blood and replaces it with other fluids
- Anti-bodies removed
- May help reduce symptoms of GBS
What professionals may be used in MDT care? (2)
- PT to reduce stiffness of muscles and contracted joints and regain muscle strength
- SLT: speech and swallowing abilities
Define myasthenia gravis
- Rare, long-term autoimmune disorder causing episodic muscle weakness and easy fatiguability
What is myasthenia gravis caused by? (2)
- Autoantibody and cell-mediated destruction of acetylcholine receptors
- Prevents a muscle contraction occuring
In what age groups is myasthenia gravis more common in? (3)
- Young women (20-40)
- Older men (50-80)
But may occur at any age
What is the annual incidence in myasthenia gravis?
1 in 500,000
what is the prevalence of myasthenia gravis?
1 in 2,500-200,000
Give 4 uncommon forms of myasthenia gravis
- Ocular MG
- Congential myasthenia
- Neonatal myasthenia
- Juvenile MG
Describe ocular MG
Involves only the eye muscles (15% of cases)
Describe the aetiology of congenital myasthenia (2)
- Rare autosomal recessive disorder that begins in childhood
- Not immune-mediated and results from presynaptic or postsynaptic abnormalities
What are the symptoms of congenital myasthenia? (6)
- Opthamoplegia is common (weakness/paralysis of one or more eye muscles)
- Generalised weakness in arms and legs
- Delays in motor skills
- Feeding difficulties
- Weak eyelids
- Poor head control
Describe neonatal myasthenia (3)
- Affects 12% of infants born to women with MG
- Due to the antibodies that passively cross the placenta
- Caused generalised muscle weakness which resolves in days-weeks as antibodies decline
Describe juvenile MG (3)
- Typically develops in female adolescents (10% of MG cases)
- Life-long condition that may go in and out of remission
- Excessively tired after little activity, problems in swallowing and chewing
Describe the aetiology of myasthenia gravis (2)
- Autoimmune attack on postsynaptic acetylcholine receptors
2. Disrupts neuromuscular transmission at neuromuscular junction
What is the trigger for autoantibody production in myasthenia gravis? (4)
- Unknown
- Some cases linked to tumours in thymus gland
- Variations in certain genes may increase risk of MG
- Associated with abnormalities in the thymus, autoimmune hyperthyroidism and other autoimmune disorders
Describe the role of the thymus in myasthenia gravis (2)
- Unclear but 65% of patients have thymic hyperplasis
2. 10% have thymoma (about half are malignant
What are precipitating factors of myasthenia gravis?
- Infection
- Surgery
- Certain drugs
Describe the inheritance patterns of myasthenia gravis (2)
- Not directly inherited
2. Genetic predisposition to autoimmune disease can run in families
When do the symptoms worsen in myasthenia gravis?
- Worsen with muscle activity and improve with rest
What are the symptoms of myasthenia gravias? (11)
- Droopy eyelids
- Double or blurred vision
- Difficulty making facial expressions
- Dysphagia
- Dysarthria, nasal voice
- Weak arms, legs, fingers, hands of neck
- Shortness of breath/serious breathing difficulties
- Unstable/waddling gait
- Chest infections
- Difficulty with physical tasks
- Aching muscles after use
What is a myasthenia crisis? (3)
- 15-20% have severe episodes at least once in their life
- Sometimes triggered by infection
- Arms and legs may become extremely weak but do not lose sensation
Summarise the diagnosis of myasthenia gravis (7)
- Ice pack or rest tests
- Electromyography (EMG)
- Blood tests
- Endrophonium injection
- CT or MRI to assess thymus gland
- Genetic tests
- Muscle biopsy
Why is an ice test used in myasthenia gravis? (3)
- Weakness lessens in cooler temperature
- Apply ice to eyes for two minues
- A positive result is full or partial ptosis
Why are blood tests used to diagnose myasthenia gravis? (2)
- Detect antibodies of acetylcholine receptors and check for other disorders
- Not everyone will have high levels, particularly if only affecting eyes
Why is endrophonium used to diagnose myasthenia gravis? (3)
- If patient has sudden improvement in muscle strength - MG is likely
- Usually done if still unclear what’s causing symptoms
- Rarely done as there is a risk of serious side effects eg. slow heartbeat, breathing problems
What is the prognosis of myasthenia gravis? (3)
- With treatment: most improve their weakness and live full lives
- Sometimes respiratory failure - medical emergency
- Some may go into remission where muscle weakness disappears
Summarise the treatment of myasthenia gravis (5)
- Medication
- Supportive care
- Avoiding triggers
- Surgery
- Immunomodulating treatment
Give 5 medications with a used in myasthenia gravis
- Anticholinesterase drugs to relieve symptoms
- Corticosteroids
- Steroids (eg. prednisolone)
- Pyridostigmine
- Immunosuppresents
What is the role of pyridostigmine in treatment of myasthenia gravis? (3)
- Helps electrical signals travel between nerves and muscles
- Can reduce muscle weakness but only lasts a few hours
- Side effects: stomach cramps, diarrhoea, muscle twitching and nausea
What is the role of steroids in treatment of myasthenia gravis? (2)
- Reduce the activity of the immune system to stop attacking the nervous system
- Unpleasant side effects eg. weight gain, mood swings, increased infection risk
Give 2 examples of immunosuppresents
Azathioprine
Mycophenolate
When is immunomodulating treatment used? (3)
- Severe cases/myasthenic crisis
- Slows disease progression and helps relieve symptoms
- Not used in congenital treatment
What are 2 types of immunomodulating treatment?
- Plasma exchange
2. Intravenous immunoglobulin
What type of surgery is used to treat myasthenia gravis?
Remove the thymus gland (thymectomy)
What are the benefits of thymectomy in myasthenia gravis?
- Improves symptoms in those with a large thymus (not in those which has grown abnormally)
- Can reduce doses of steroids and immunosuppresents
- Reduces hospital visits due to worsening symptoms
- 50% have stable, long-lasting remisions after