Fusion: 1-3 Horner's - Week 12 Flashcards
What are the relevant parts of this patient’s presentation? (4)
49 yr old woman
collecting new reading glasses
ache in neck and left arm for past week
left lid droopy (ptosis)
Define unilateral ptosis
palpebral fissure symmetry of >/= 1mm, affecting upper eyelid
What can unilateral ptosis result from? (3)
dysfunction of upper-eyelid muscles alongside injury
inflammation or lesions of the lids or orbit
eye surgery
What 2 muscles are involved in the raising of the upper eyelid? What is each muscle innervated by?
Levator palpebrae superioris (CN3 innervation)
Superior tarsal muscle (sympathetic innervation)
What are the 2 common forms of ptosis
acquired and congenital
What are the common causes of ptosis? (5)
age-related
trauma, mechanical
myogenic
neuromuscular
neurogenic
Name 2 myogenic causes of ptosis
Chronic Progressive External Ophthalmoplegia (CPEO)
Oculopharyngeal Muscular Dystrophy
Name 1 neuromuscular cause of ptosis
Myasthenia Gravis
Name 2 neurogenic causes of ptosis
CNIII palsy
Horner’s syndrome
What changes occur to the levator muscle with age-related ptosis? (3)
loss of muscle tone
inability to hold upper lid in proper position
disinsertion of the aponeurosis
What is ‘aponeurosis’? Explain what it is (1) and its function. (4) What is it important for? (2)
An aponeurosis is a type of connective tissue found throughout the body.
Aponeuroses provide an attachment point for muscles to connect to bone, and can also envelope muscles and organs, bind muscles together, and bind muscles to other tissues. They are important for muscle movement and posture.
What are the risk-factors for age-related ptosis? (4)
chronic CL wear
rubbing of eyes (conjunctivitis)
systemic health conditions
cataracts surgery
(also age as well obviously!)
What condition is a common cause of blepharitis?
trauma-related ptosis
Name the 5 sub-categories of trauma-related ptosis
traumatic myogenic - (laceration of levator)
traumatic aponeurotic - (when eyelid vigorously pulled)
mechanical - (scar tissue)
neurogenic - (neurotoxins, head/neck injury, FBs)
mixed-mechanism
What tests can you use to diagnose CPEO? (3)
comprehensive physical exam
goldmann perimetry: (map range of EOM movement)
muscle biopsy
Describe the ptosis seen in CPEO. Can it be unilateral? (3)
Ptosis asymmetrical. Can be unilateral. Limited ocular motility
What tests can you use to diagnose OPMD? (oculopharyngeal muscular dystrophy)
Positive family history: 2 or more generations
Presence of ptosis + dysphagia: (inability do drink 80ml cold water in 8 seconds)
PCR testing for PABPN1 mutation
What are the ptosis related features for OPMD? (4)
slowly progressive bilateral ptosis
EOM weakness
dysphagia
proximal limb weakness
What tests can you use to diagnose Myasthenia Gravis? (3) (also giving very brief explanations)
Edrophonium (tensilon) test: inhibit acetylcholinesterase
Ice test: useful for ptosis. ice on lid (2-5 min) - transient improvement in ptosis
Serum anti-ACh receptor/muscle-specifi kinase antibody titre
Describe the general features of Ocular Myasthenia Gravis (3)
Ptosis most common sign: unilateral or bilateral
Weakness of EOM: incomitant strabismus
Most progress to general Myasthenia Gravis
Can general myasthenia gravis involve neck fatigue?
yes. Also can have jaw fatigue
How does bell’s palsy (facial nerve palsy) affect the face?
weakness/paralysis of all muscles on one side of the face
How fast is the onset of bell’s palsy
sudden onset
How does 3rd nerve palsy arise?
lesion/damage to the oculomotor nerve (3rd nerve)
What proportion of 3rd nerve palsy sufferers have ptosis on first presentation?
86%
Describe the clinical features of 3rd nerve palsy (3)
Dilated pupil with sluggish reaction
Affected eye positioned down and out (limited adduction, infraduction, supraduction)
Manifestations depend on affected area of CNIII track
How does Horner’s Syndrome arise? Is it an afferent or efferent defect?
disruption of sympathetic innervation to the eye (is an efferent defect)
In regards to the patient’s left lid ptosis: what should you consider in history taking? (5)
Onset
Does it vary in severity
Has px had ocular surgery
Any trauma
Any history of amblyopia
How can we rule out or diagnose or distinguish if 3rd nerve palsy or Horner’s Syndrome as the cause of ptosis? (i.e. what test can we use?)
Pupil testing
(incidentally: the patient here has horner’s syndrome)
What key feature should we look for to identify Horner’s Syndrome when testing pupils?
anisocoria
Define anisocoria
inequality in the size of the pupils of >/= 0.6mm
Name the potential causes of anisocoria (4)
physiological
pharmacological exposure
direct damage to iris muscles
interruption to the sympathetic/parasympathetic pathway
Describe the parasympathetic pathway of iris innervation (4)
Pre-gang: EW-nucleus via 3rd nerve – cil. gang.
Post-gang: Short cil. nerve — sphincter
Describe the sympathetic pathway of iris innervation (5)
Pre-gang: exits T1 — sup cerv. gang.
Post-gang: follow carotid artery – long cil. nerve – dilator
In Horner’s syndrome, when would we expect to see greater anisocoria? Why?
Since it’s a sympathetic problem. Expect to see greater anisocoria in dim
Name 3 parasympathetic-issue causes of anisocoria. When would anisocoria be greater in these conditions?
3rd nerve palsy
Adie’s tonic pupil
Parinaud’s syndrome
Would expect anisocoria greater in the light in these conditions
Is it a problem if Horner’s is accompanied with pain?
YES! DANGER!
How can you localise the lesion in horner’s syndrome?
Pharmacological tests combined with imaging techniques (MRI)
What are the 3 classical signs of Horner’s Syndrome?
Miosis
Ptosis
Facial anhydrosis
How might lesion to the sympathetic innervation of the iris occur? (4)
May arise from:
- carotid artery dissection, tumour development in certain areas like the neck
- lesion in midbrain, brain stem, upper spinal cord, neck, eye orbit
- inflammation or growths affecting lymph nodes of neck
- surgery or trauma to the neck or upper spinal cord
(note: horner’s can also be idiopathic, occurring for no apparent reason)
Describe the process of the 1st neuron in the 3 neuron arc of sympathetic eye innervation (2)
Hypothalamus pass down through the midbrain and pons
Terminate at spinal level C8-T2
Describe the process of the 2nd neuron in the 3 neuron arc of sympathetic eye innervation (2)
Pre-gang fibres exit spinal cord at T1 and enter cervical symp. chain
Ascend symp. chain –> sup. cerv. gang.
Describe the process of the 3rd neuron in the 3 neuron arc of sympathetic eye innervation (3)
sup. cerv. gang. –> cavernous sinus
enter orbit through sup. orbital fissure
iris dilator muscle and eyelids and sweat glands on face
Which is more dangerous: Pre-ganglionic or Post-ganglionic Horner’s syndrome?
Post-ganglionic is more dangerous = serious pathology with high incidence of malignancy)
(pre-ganglionic = benign causes)
What symptoms are associated with a 1st order neuron lesion in horner’s? (5)
ataxia
vertigo
nystagmus
hemisensory loss
dysarthria + dysphagia
What symptoms are associated with a 2nd order neuron lesion in horner’s? (3)
prior trauma
facial, neck, shoulder, or arm pain
previous thoracic or neck surgery
WAIT A MINUTE: DID SOMEBODY SAY ARM PAIN!?!?!?? The patient ALSO had ARM PAIN!!!
What symptoms are associated with a 3rd order neuron lesion in horner’s? (2)
distribution of 1st and 2nd trigeminal nerve numbness
diplopia from 6th nerve palsy
What pharmacological agent is considered the gold standard for testing for horner’s?
cocaine drops. If horner’s, affected eye doesn’t dilate even with the drops
What is the physiological basis behind cocaine eye drops?
cocaine blocks the reuptake of NAD, allowing NAD to accumulate in the synaptic cleft
(in pre-ganglionic horner’s: little-no NAD is released in the first place meaning blocking reuptake doesn’t change anything)
(in post-ganglionic horner’s: cocaine has no effect here as well as the presynaptic terminal is not functional)
What is an alternative to cocaine drops that can be used to confirm horner’s? What effect does it have?
Apraclonadine (causes reversal of anisocoria where the affected pupil actually dilates and normal pupil stays same size)
What is the physiological basis behind aproclonidine?
is and alpha-2 agonist that acts on the presynaptic terminal and decreases NAD production
Why does horner’s react to aproclonidine so well?
In horner’s there is an upregulation of postsynaptic alpha-1 receptors – resulting in supersensitivity to apraclonidine for dilation in both pre- and post-ganglionic horner’s (so horner’s pupil dilates)
What drop can we use to differentiate between a lesion affecting 1st or 2nd order neuron from a lesion affecting the 3rd? (in horner’s)
Hydroxyamphetamine
(3rd order horner’s pupils won’t dilate as well, whereas normal/1st/2nd order dilate)
When is the hydroxyamphetamine test considered positive for post-ganglionic horner’s?
when the anisocoria increases by at least 1mm
What is the physiological basis behind hydroxyamphetamine?
it releases stored NAD from the presynaptic vesicles
