Ocular emergencies Flashcards
What are some important risk factors for acute angle closure glaucoma?
AACG:
- Progressive headache (usually on side affected)
- Female (shallower anterior chambers)
- Blurred vision (cornea becomes oedematous leading to corneal clouding, following increase in intra-ocular pressure)
- History of vomiting
- Glasses worn for near vision (hypermetropic patients have smaller eyes and shallower anterior chambers)
What clinical signs are suggestive of a diagnosis of acute angle closure glaucoma?
- Dilated pupil
Unreactive if light shone through it - Red eye
Due to inflammation, also accompanies pain and loss of vision - Blue iris
- Cloudy cornea
The cornea becomes oedematous and hazy, this can be picked up using an opthalmoscope at +10
What is the normal intra-ocular pressure?
10-20mmHg
What is used to check intra-ocular pressure?
Goldmann tonometer
What is the treatment offered for AACG?
Peripheral iridotomy
When might we use a peripheral iridotomy phrophylactically?
If the patient has already had AACG in one eye, and the other eye is found to have a shallow anterior chamber/raised IOP
The other eye is always treated prophylactically to prevent AACG from affecting it in the future
What follow-up is recommended following resolution of AACG?
Follow up the patient in a glaucoma clinic with visual field testing
What should we be mindful of prescribing for a patient with a history of AACG?
- Phenylephrine
- Tropicamide
Both of the above drugs can increase pupil size, and cause narrowing of the drainage angle
What is a ‘cherry red spot’ seen on fundoscopy suggestive of?
Central retinal artery occlusion
What happens in central retinal artery occlusion?
- The retina becomes ischaemic and pale
- Choroidal circulation remains, and is seen as a cherry red spot
- The retina is at it’s thinnest over the central macula area (fovea), so this is where choroidal circulation can be seen
If a patient has suspected central retinal artery occlusion, what must be ruled out?
Giant cell arteritis
What are risk factors for central retinal artery occlusion?
- Giant cell arteritis
- Hypercholesterolaemia
- Hypertension
- Atherosclerosis
Other risk factors:
- Diabetes
- Previous TIA
- Previous angina
- Smoking
What should be done for a patient with suspected central retinal artery occlusion?
- Full history (CV) and exam
- Suspect GCA until proven otherwise
- Consider high dose prednisolone if GCA
- Refer urgently to opthamology
- Early treatment can restore vision
- This condition is similar to having a stroke - increasing ischaemic time leads to poorer outcomes
What are some risk factors for retinal detachment?
- Trauma
Causes high velocity vitreous movement, and traction on the retina - Myopia
Larger eyeballs results in a thinner retina at the far periphery, leading to an increase chance of tears/detachments
What are the signs of orbital cellulitis?
- Patient has severe pain and swelling around the eye
- Vision is reduced
- Eye movements are painful
- Fever 39C+
- Generally unwell
- Patient cannot move the eye
- Periocular swelling of the eye
- Periocular erythema of the eye
Which investigations are essential for orbital cellulitis?
- Orbital scan (MRI or CT)
- Swab from the conjunctivae
- Full blood count
- Blood cultures
Which bedside clinical assessments need to be done hourly in orbital cellulitis?
- Blood pressure
- Visual acuity
- Pulse
- Temperature
What are the most common causes for orbital cellulitis?
Often following an infection of the respiratory tract and sinuses:
- Haemophilius influenzae
- Staphyloccocus aureus
- Streptococcus pneumoniae
- Betahaemolytic streptococcus
And occasionally:
- Aspergillus
In immunocompromised patients
What are the treatments for orbital cellulitis
- Admission
- Co-amoxiclav oral is first-line
- If patient is severely unwell consider IV
- If co-amoxiclav is contraindicated/there is a pencillin allergy, administer clindamycin + metronidazole, either oral or IV
- If MRSA is suspected/convirmed, IV vancomycin or teicoplanin, OR oral/IV linezolin should be ADDED to one of the above regimes
- Optic nerve function is monitored ever 4 hours
- Treatment last for 7 days
- Surgery may be inficated if there is CT evidence of an orbital collection, or there is no response to abx, or the picture is atypical
How does pus in the anterior chamber appear?
- Eye is red and inflamed
- White ‘fluid’ level in the anterior chamber
- Called hypopyon and is the accummulation of white blood cells
What are some risk factors for infective endopthalmitis?
- Poorly controlled diabetes
- Painful sudden visual loss
- Recent ocular surgery
- Long lines
- Indwelling tubes/catheters
What is the management of infective endophthamlitis?
- Immediate sampling of intraocular fluid (vitreous tap)
- Intravitreal injection of antibiotics
What are the signs of infective endophalmitis?
- Sudden painful loss of visual acuity
- Red eye with hypopyon
- Pupil does not appear to react to light
- Poor red reflex
- No fundal view
Any patient presenting with a red eye, associated with pain and reduced vision should be referred immediately.
What is glaucoma?
- Progressive optic neuropathy
- Changes to the optic nerve head
- Patterns of visual field loss
- Leading cause of blindness
- Either open or closed angle
What is AACG?
- Emergency
- Untreated = permanent optic nerve damage
- Due to blockage in the iridocorneal angle for the outflow of aqueous humour
- Leads to increase in IOP and damage to the optic nerve
How does aqueous humour flow through the eye?
- Found in anterior and posterior chambers
- Supplies nutrients to the lens and cornea
- Produced in ciliary body in the anterior portion of the uveal tract
- Is secreted into posterior chamber in pars percata
- Then flows around the lens
- Fills the anterior chamber
- Then exits through the trabecular meshwork and the iridocorneal angle
- Then enters the canal of schlemm
- Then enters aqueous veins and systemic circulation
What are the causes of a blockage of the iridocorneal angle?
Closure is usually primary
- Severe hypetropic
- Short axial length
- Thin iris
- Thick lens
- Neovascularisation of the cornea (diabetes)
- Lens (grows with age)
- Blood clot (less common)
What are risk factors for AACG?
- Age
- Female
- Family history (first degree)
How does AACG present?
- Severe eye pain
- Occasionally headache
- Blurred vision
- Halo around lights when looking (due to corneal oedema, affects refraction)
- Nausea and vomiting
- Ciliary flush (red injection around peripheries of cornea)
- Poorly reactive pupil
- Eye is hard to touch
- Hazy cornea
What is the management for AACG?
- Refer urgently to opthalmology
- Slit lamp
- Tonometry to measure IOP
- Gonioscopy (looks at iridocorneal angle)
- Diagnosis can be made with presentation + raised IOP
What is the treatment for AACG?
- Immediate referral to opthalmology
- 1st line treatment is topical eye drops:
1. Timolol
2. Apraclonidine
3. Prednisolone
4. Pilocarpine - IV acetazolamide (carbonic annhydrase inhibitor) or mannitol
THEN
Reduce IOP using peripheral iridotomy
