Emergencies Flashcards
(80 cards)
What are the features of acute primary angle closure?
Pain - periocular, headache, abdominal Blurred vision Haloes Nausea Vomiting
What are the signs that a person with acute primary angle closure will exhibit?
Ipsilateral red eye Raised IOP (often 50-80mmHg) Corneal oedema Angle closure Fixed semi-dilated pupil Shallow anterior chamber
Why is acute primary angle closure an emergency?
It can cause optic nerve damage if not treated urgently.
What immediate treatment do we give for acute primary angle closure?
- Systemic acetazolamide 500mg IV stat
- Topical - beta blocker (timolol), steroids (prednisolone 15 every 15 for an hour, then hourly), pilocarpine (pts without own lens get phenylephrine)
What intermediate treatment do we give for acute primary angle closure?
- Continue acute regime according to guidelines
- Consider hyperosmotics e.g. mannitol
- Check IOP hourly
- Review diagnosis if no improvement
What definitive treatment do we give for acute primary angle closure?
Surgical peripheral iridotomy, usually at 11 and 2 o’clock positions for free flow of aqueous
What are the complications of acute angle closure glaucoma?
Loss of vision
Repeat of acute attack
Attack in contralateral eye
Central retinal artery/vein occlusion
Who can we offer prophylactic peripheral iridotomy to?
Those with shallow anterior chambers, to prevent acute angle closure glaucoma.
A young patient presents after a hit to the head with sudden decreased visual acuity and double vision.
What other signs and symptoms are suggestive of a carotid-cavernous fistula?
Audible bruit in carotids Pulsatile proptosis wit bruit Orbital oedema Injected chemotic (swollen) conjunctiva Increased IOP May have ophthalmoparesis (CN III/VI usually) Disc swelling Anterior segment ischaemia
How should a suspected AV fistula be investigated?
Orbital imaging (Doppler US/CT)
How should a high flow AV fistula be managed?
Closure by catheter embolisation
What is the blood flow to the retina, and why is this important wrt ophthal emergencies?
Central retinal artery (branch of ophthalmic from the internal carotid) which divides into superior and inferior, each of which divide into nasal and temporal branches.
Outer retina is supplied by ciliary artery branches from the ophthalmic artery.
CRAO can affect one or multiple branches, and there is no collateral supply as these are all end-branch arteries.
What are the most common causes for CRAO?
- Atherosclerosis
- Embolism usually from atherosclerosed/stenosed carotid artery
Other than atherosclerosis/embolism, what are the causes of CRAO?
- Inflammatory - Giant cell arteritis, SLE, granulomatosis etc.
- Thrombophilic disorders
- Infection
- Pharmacological (OCP, cocaine)
- Ocular trauma
When is the optimum treatment window for CRAO?
Within 90-100 minutes of onset
A patient presents to eye casualty with acute painless unilateral loss of vision. What is your top differential?
Central retinal artery occlusion
A patient presents to eye casualty with acute painless unilateral loss of vision. What do you expect to see on ocular examination and fundoscopy?
Relative afferent pupillary defect.
White swollen retina with cherry-red spot at the macula.
Segmentation of blood column in arteries.
A patient presents to eye casualty with acute painless unilateral loss of vision. What might you find on general examination of this patient?
Carotid bruits
Heart murmurs
AF
HTN
A patient presents to eye casualty with acute painless unilateral loss of vision. What are you differentials?
CRAO Retinal detachment (floaters/curtain) CRVO (fundoscopy) Acute glaucoma (painful) Acute optic neuritis (painful)
How is ?CRAO investiagted?
Fluorescein angiography and optical coherence tomography is diagnosis unsure.
Aim to rule out underlying causes e.g. AF, heart murmur, carotid disease.
ESR and CRP if over 60 for ?giant cell arteritis.
Bloods - coag, FBC, vasculitis screens, lipids, fasting glucose.
How should CRAO be managed?
As an emergency.
Treat giant cell arteritis is suspected (iv then oral steroids).
Urgent modification of RFs.
There is no Rx to reverse the visual loss :( Just have to try and reperfuse.
How can we try to reperfuse the eye in CRAO?
- Firm ocular massage (works only occasionally)
- Reduce IOP with anterior chamber paracentesis, acetazolamide/mannitol/beta blockers.
- Dilation of artery e.g. with sublingual isosorbide dinitrite
- Intra-arterial fibrinolysis w/ urokinase
A person present to eye casualty having been sprayed in the eye with an unidentified substance.
Which chemical burns can cause significant injury to the eye?
Acid and alkali
Deterrents e.g. tear gas/mace, pepper spray, mustard gas, chlorine, superglue
How does acid cause damage to the eye?
Reacts with protein and fat causing tissue destruction