opthalamology Flashcards
what is blepharitis?
chronic inflammation of lid margin
who is at more risk of blepharitis?
- More common and severe in elderly
what are the symptoms of blepharitis?
Symptoms: often intermittent with exacerbations and remissions occurring over long periods
- Burning, itching – maybe crusting
- Worse in mornings – more crusty
- Both eyes are affected
- Recurrent hordeolum – styes
- Contact lens intolerance
what conditions are associated to blepharitis?
dry eye disease
seborrheic dermatitis
rosacea
how do you manage blepharitis?
- Requires ongoing maintenance, self care – eyelid hygiene and warm compresses
- Diluted baby shampoo with warm water and wipe along margins
- If self care is ineffective topical antibiotic eg chloramphenicol
what is chalazion?
Meibomian cyst
what is the pathophysiology of chalazion?
The cyst is a sterile, inflame granuloma caused by obstruction of sebaceous gland
Pathophys: causes gland to enlarge and rupture spontaneously or persist as chronic nodule
- May develop acutely with oedematous erythematous eyelid or arise as firm, painless nodule
- If secondary infection: can spread from preseptal cellulitis requiring oral/ IV Abx orbital or periorbital cellulitis
what is the management of Meibomian cyst (chalazion)?
Management: mainly self limiting
- Warm compress and gently massage – go towards eye lid to follow normal path of drainage
- If persistent: refer to ophthalmologist incision and curettage
- No treatment if meibomian cyst is small and asymptomatic
what is the other name for a stye?
hordeolum
what is a stye/ hordeolum?
acute localised infection or inflammation of eyelid margin. Bacterial infection is usually caused by staph infection
where is an external stye located?
on eyelid margin
what causes an external stye?
- Infection of eyelash follicle and associated with sebaceous apocrine gland
where is an internal stye?
occurs on conjunctival surface of eyelid
what causes an internal stye?
- Infection of meibomian gland – situated within tarsal plate
how do you manage a stye?
- Self care: usually self limiting and rarely causes serious complications
- Warm compress 5-10 mins 2-4x daily
- Do not attempt to puncture stye – no squeezing
- Avoid eye makeup/ contact lens
- Painful styes: eyelash form infected follicle removed, incision and drainage, topical Abx ( chlorophenicol)
- Refer: if not improving or large/ painful
what is ectropion?
outward rotation of eyelid margin
what can cause ectropion?
Pathophys: most commonly due to horizontal lid laxity – loss of elasticity and muscle tone
- Other aetiology: due to skin trauma, burns, skin tumours, actinic changes to skin due to prolonged sun exposure
- Paralytic causes: facial palsies
what are the symptoms of ectropion?
Symptoms: sore red and watery eye
what is the management of mild ectropion?
- Mild: no treatment but advise rubbing eye lids may cause more lid laxity tapping lids closed at night when risk of corneal exposure
what can be used to manage moderate ectropion?
- Ocular lubricants: for tear deficiency related to symptoms – drops in day and ointment in day
what is entropion of the eyelid?
inward rotation of tarsus and lid margin- usually lower eyelid
what is the pathophys of entropion?
Pathophys: loss of elasticity and muscle tone of eyelids usually with AGE
- LASHES THEN come into contact with ocular surface
- Presents as foreign body sensation and irritation eith red watery eye and blurring of vision
what ways can manage entropion?
- Tapping eyelid to check
- Injecting muscles of eyelid with BOTOX
- Lubricating eye to protect front of eye
- Severe refer and small operation can be performed to turn eyelid back to normal position
what is ptosis?
droopy eye
>2mm of cornea covered by eyelid
what is pseudoptosis?
one eye affected
what could be unilateral differentials of ptosis?
involutional changes, congenital, 3rd nerve palsy, Horner’s syndrome, trauma to levator muscle
what could be bilateral ptosis differentials?
involutional changes, congenital, myasthenia gravis (one side can be more affected), myotonic dystrophy, mitochondrial myopathies, dermatochalasis, trauma to levator muscle
what allows for eyelid elevation?
: oculomotor nerve innervates: levator palpebrae and supreriorns as well as superior tarsal palate
what chain allows for pupil constriction?
- Pupil constriction: parasympathetic
what chain allows for pupil dilation?
sympathetic
what allows for extra-ocular movements?
- Extra-ocular movements: innervates trochlear (superior oblique), abducens (lateral rectus) and oculomotor (medial rectus, superior rectus, inferior rectus and inferior oblique)
when is dermatochalasis frequent?
patients with recurrent blepharitis which have now resolved
what is dermatochalasis?
- Excessive skin on upper and lower eye lid
- Complicated with entropion and blepharitis
what is involutional ptosis?
drooping of eyelids seen in elderly - normal
what are the genetic components of myotonic dystrophy?
Pathophys: trinucleotide repeats (DM1) and tetranucleotide repeats (DM2) – seen through generations
- Normally have 5-30 repeats, this has 50 to 2000 repeats
faulty genes
describe the muscle weakness that is seen within myotonic dystrophy?
- Muscle weakness and wasting (lower motor neurone) – bilateral ptosis, wasting of muscles in hands, face, jaw – little lines on forehead (comes in towards cheekbones) , hatchet jaw (comes in but droopy)
describe the prolonged contractions/ delayed relaxation seen within myotonic dystrophy?
- Prolonged contraction/ delayed relaxation: percussion myotonia, difficulty in relaxing – grip (when grip hands, they do not release instantly like you would once told to release – hands may spasm after release)
apart from muscle weakness, delayed relaxation/ prolonged contraction, what else is seen within myotonic dystrophy?
- Male pattern balding
- Cataracts – can be in one eye
- Diabetes – type 1
- Gynaecomastia
- Low IQ
- Heart conduction defects – heart block, AF, arrhythmias
what is the pathology behind horners syndrome?
Pathophys: sympathetic supply to eye interrupted and the parasympathetic overrides the affected side
- Sympathetic chain runs form base of skull to coccyx – can affect any nearby structures on route eg aorta
what are the symptoms seen within horners syndrome?
Symptoms: ptosis, meiosis (small pupils), enophthalmos (sunken in eyes), anhydrosis (little or no sweating of that side of face)
what central aetiologies can lead to horners?
- CVA – central vascular accident – interruption of blood flow to brain
- Syringomyelia - Syringomyelia is a neurological disorder in which a fluid-filled cyst (syrinx) forms within the spinal cord. The syrinx can get big enough to damage the spinal cord and compress and injure the nerve fibres
- Meningitis and encephalitis
- Brain/ spinal cord tumour
- Trauma – central
what preganglionic pathologies (in chest) cause horners?
- Cervical rib – should not be there
- Lymphadenopathy
- Thyroid mass – goitre, tumour, surgery
- Lung apex pathology eg Pancoast tumour
- Thoracic aorta, subclavian aneurysm – aortic dissection
- Trauma – chest
what post ganglionic pathologies cause horners (neck and upwards in spine)
- Carotid artery dissection/ aneurysm
- Cavernous sinus thrombosis
- Middle ear infection
- Cluster headaches
- Trauma – neck and head
what are the symptoms of myasthenia gravis?
Symptoms: better in morning and worsening in evening – fatiguability
- Ocular – ptosis and diplopia (double vision) first symptom
- Bulbar – dysphagia, dysphonia and dysarthria
- Facial – droopy mouth, less forehead lines,
- Limb, trink, resp weakness as it progresses
what tests demonstrate fatigability indicating myasthenia gravis?
- Simpsons; look up and observe for worsening ptsosis
- Repeatedly test flap arm for a minute and then test power (initially push down on chicken elbows and then flap arms for 30x times and then push down again on chicken elbows should easily push to sides)
- Reflexes and sensation are usually in tact
- Muscle wasting can occur if prolonged activity
what conditions is myasthenia gravis associated with?
- Associated with other AI conditions especially thyroid
what investigations are done for myasthenia gravis?
- TENSILON test – using edrophonium and atropine will improve symptoms in seconds
- Acetylcholine receptor antibodies
- EMG – assess fatiguability
- Imaging of thymus – CT this makes the auto antibodies
- Spirometry – access resp muscle involvement – FVC or single breath counting
how do you manage myasthenia gravis?
- Pyridostigmine – acetylcholinesterase inhib
- Steroids and immunosuppressives – azathioprine, methotrexate
- Thymectomy if hyperplasia oh thyoma
what is labert - eaton myasthenic syndrome?
- Antibodies to pre-synaptic voltage gates calcium channels in NMJ
- Associated with AB to voltage gated calium channels
what symptoms are seen with lamert -eaton myasthenic syndrome?
Symptoms: weakness in arms and legs
what is lambert-eaton myasthenic syndrome associated to?
- 60% have associated malignancy usually small cell lung cancer
what are the signs of 3rd nerve palsy?
Symptoms:
- Ptosis
- Mydriasis – enlarged pupil
- Eye facing down and out
- Enophthalamus
what can cause 3rd nerve palsy?
Aetiology: diabetes, atherosclerosis, posterior communicating artery aneurysm, SoL, brain infection/ inflammation, cavernous sinus thrombosis, MS
