Myogenic Palsies - Miriam Flashcards
What is myasthenia Gravis?
This is an autoimmune condition, Life threatening disease in certain cases
It is when the muscles are very weak.
Adult MG?
Ocular Myasthenia: Limited to the eye. If still only eye muscles then unlikely to become generalized.
Mild to moderate : Often slow onset of symptoms eyes usually first.
Acute fulminating : RAPID ONSET - AFFECTS RESPIRATORY MUSCLES
Late severe : develops after 2 years of initial muscle weakness
What are the three paediatric groups of children with MG?
1) Neonatal
2) Congenital
3) Juvenile
What does neonatal mean?
Born to a myasthenic mother, self limits in 6 weeks
What does congenital MG mean?
Infants born to non-myasthenic mothers
What does juvenile MG mean?
Develops in infancy, spontaneous remission
What are four types of adult MG?
1) Ocular myasthenia
2) Mild to moderate
3) Acute fulminating
4) Late severe
What is ocular MG?
Limited to eye muscles only
If a px has ocular MG for 2 years, is it likely for it go on to other muscles of the body and become generalised?
No
What is mild to moderate mg?
Generalised Slow onset of sx + respiratory muscles not affected
What is acute fulminating mg?
Generalised, rapid onset, affects respiratory muscles- THEY CAN DIE
What is late severe mg?
Generalised, start with mild or ocular but after 2 years they start to develop severe form
What is drug-related MG?
MG is induced by D-pencillamine
What is D-pencillamine used to treat?
Rheumatoid arthritis and systemic lupus
why is anisha so bent
becasue she wa sborn that way
Why does muscles fatigue in MG?
- antibodies prevent ACh binding at synaptic gap= reduction of ACh uptake
- more ACh produce so muscle contraction can occur
- body runs out of ACh= muscles tired
Which muscle types are affected ?
Striated muscles
What are some general sx an mg px may experience?
General fatigue and lack of energy
What are some limb related sx a mg px may experience?
Difficulty getting out a chair or climbing downstairs
What are some facial issues a px with mg may experience ?
Lack of facial expression
What other sx may they complain of?
Problems with speech, breathing and swallowing
What two ocular symptoms marks the onset of 70% of mg cases?
Ptosis and diplopia
Is Ptosis often bilateral or unilateral?
Bilateral but asymmetric
What happens to the ptosis with increase of fatigue?
Ptosis gets worse
What is often seen in an attempt to elevate an mg eye?
Frontalis o/a
To try to lift the ptotic eye, what may happen to the contralateral eye?
Lid retraction
If you detect ptosis, what is a big question you must ask in Relation to mg?
Does it get worse throughout the day or when you do exercise
What can you do in practice to investigate if ptosis is related to mg?
Muscle fatigue-
Ask the px to elevate their eyes and look at a pen torch for a minute, measure the ptosis before and after to see if it increases in size
What do you do to see if a px has Cogans lid twitch when trying to investigate ptosis?
- Depress eyes for 15 seconds by looking at a pen torch and return eyes to pp
- Lid initially moves above ptotic level and the comes back down
E.g the eye lid overshoots
What do you do to see if a px has Gorelick’s sign when investigating Ptosis?
- Hold up more ptotic lid
- The ptosis on the less effects side starts to increase
What is the ice pack test when investigating ptosis
An ice pack place on both lids for 2 mins and if px ptosis improves = strong indication of MG
Will a px with MG have vertical or horizontal dipl?
It varies
What question is good to ask a px who is complaining of dipl and you may suspect mg?
Does the dipl increase throughout thr day or with exercise
If using a Hess chart what should you write on it ?
Date but also the time performed
What may you find if a px has mg and you have done multiple Hess charts ?
Different palsies and weaknesses on each time done as different muscles are more weak on different occasions
How can you check for obicularis weakness (when you scrunch up your eyes)?
Cannot squeeze their eyes tight enough for eyelashes to be buried + when a clinician tries to open their eyes, it only requires gentle pressure
What tests should you do with a suspect MG px?
- Ocular motility
- PCT
- Convergence
- PFR
- Hess chart
What are some good questions to ask a suspect MG px?
- Do sx increase with fatigue?
- Do they get worse after exercise?
(Remember early stages may be intermittent weaknes)
How can MG be diagnosed for general MG?
With a blood test which detects those antibodies that prevent bind of Acetylcholine
*this isn’t amazing for those px who only have ocular MG
How can mg be detected by looking at an mg px’s thymus?
Large thymus + tumours in the thymus which can be seen with a CT or MRI scan
What is the Tensilon test ?
Test used to detect MG by:
- Being injected with anticholinesterase
- Then watch fatigue muscles recover
- Lasts 5 mins
-May want to do an EMG before and after
What is bad about Tensilon test?
Adverse reactions such as cardiac arrhythmias
What is the sleep test?
Ask the px to rest for 30 mins and see of ptosis improves
What is strongly associated with TED?
MG
Name the 5 tests to detect MG (not optom related)
1) Blood test
2) tensilon test
3) Enlarged thymus on MRI/CT scan
4) Sleep test
5) Noting ocular fatigue when carrying out tests such as OM
What 4 systemic treatments of MG?
- Pyridostigmine
- Immunisuppresive systemic steroids
- Plasmaphoresis
- Thymectomy
What is Pyridostigmine?
Longer acting anticholinesterase
What does Plasmaphoresis do?
“Clean the blood“ which Reduces level of circulating antibody or circulating immunoglobulin
What are three ocular treatments for mg?
- Ptosis prop (glasses or a cls)
- occlusion - for dipl
- Surgery
What are three occlusive ocular treatments for mg?
Blenderm (surgical tape) on glasses
Frosted lenses
Occlusive CLs
Why is surgery contradicted for mg pxs?
Only allowed to be carried out if stable for a long term
What is Lambert-Eaton Rooke syndrome? (LERS)
Issue is presynaptic, proximal limb weakness
What is the key difference between MG and LERS?
MG is an issue POST-synaptic and LERS is an issue PRE-synaptic
What do you have an increased risk of if you have LERS?
Small cell carcinoma (this is a cancer) - risk reduces after having it after 2 years
What are 4 clinical characteristics of LERS ?
- Limb weakness
- Resting action potential of muscles reduced
- Muscle’s action potential increases after repetitive stimulation
- dry mouth
What are some ocular characteristics of LERS?
50% have ptosis
EOM involvement unusual
Response to Tensilon unpredictable
What are the three managements of LERS?
1) Exclude malignancy (small cell carcinoma)
2) Ptosis props
3) Guanidine hydrochloride drops
What is guanidine used to treat ?
Muscle weaknesses
What does CPEO stand for ?
Chronic progressive external ophthalmoplegia
What are 6 characteristics of CPEO?
- Progressive symmetrical loss of OM
- Progressive symmetrical bilateral ptosis
- Loss of Bell’s reflex
- May not complain of dipl
- During early stages due to the asymmetry dipl may be complained of
- Orbicualris weakness
Here is a girl with CPEO, you can see her bilateral ptosis getting progressively worse
Why are pupil responses not affected by CPEO?
Only striated muscles are affected and pupillary response are conducted by smooth muscle
What describes the term of end stage of CPEO?
“FROZEN EYE”- they have very little eye movement
What is the aetiology of CPEO?
Mitochondrial myopathy
What syndrome is associated with CPEO?
Kearne-Sayre-Daron syndrome
What are some features of Kearne-Sayre-Daron syndrome?
- Onset before 20 years old
- Fine pigmentary retinopathy
-Heart conduction block
Is CPEO the most common mitochondrial myopathy ?
Yes
What is the management of CPEO if they complain of diplopia?
Prisms
Occlusion (cls, blenderm, frosted glasses)
Surgery
Why would you do surgery for CPEO?
If the eyes are grossly fixated eccentrically
What is orbital myositis?
Inflammation of one or more of the EOM
Is orbital myositis normally uni or bi lateral?
Unilateral
What are 6 signs and symptoms someone with orbital myositis may have?
1) Proptosis
2) Pain
3) Lid oedema
4) Photophobia
5) Conjunctivitis
6) limitation of EOM
*remember this is because the muscles are very inflamed
What is associated with orbital myositis ?
Autoimmune conditions
What are 5 DD of orbital myositis?
Orbital cellulitis
Orbital abscess
Hematoma
Graves’ disease TED
Tumours
What is a hematoma ?
an area of blood that collects outside of the larger blood vessels- like a bad bruise
(Priyesh gives hematomas)
What instrument is used to measure proptosis?
Exophthalmometer - measures by how much the eye is protruding, measure from the side
What does this CT scan show?
Px with orbital myositis (look at those inflamed EOM + proptosis)
How is orbital myositis managed?
Systemic steroids but can be self limiting
What is rhabdomyosarcoma?
Highly malignant tumour of the striated muscles
Does rhabdomyosarcoma Normally occur in children or adults?
Children - in their first decade of life I
Are rhabdomyosarcomas more prevalent in boys or girls ?
Boys
As there is a VERY rapid growth of this tumour with rhabdomyosarcoma, what will you see?
Proptosis
What are some early signs of rhabdomyosarcoma?
Tropia and limitation of eye movements
What is the treatment rhabdomyosarcoma?
Radiotherapy or chemotherapy
