Flashcards in Trauma Deck (20)
What are the three signs and a symptom of a blow-out orbital fracture?
1. Enophthalmos (initially masked by by orbital haemorrhage)
2. Infraorbital (cheek) anaesthesia (as the infraorbital nerve runs along the floor of the orbit)
3. Reduced vertical eye movement (when blow-out floor fracture; if medial wall fracture then horizontal movement impeded)
4. Diplopia (worse on straight-ahead and downgaze).
What causes the 'teardrop' sign?
Prolapse of orbital tissue into the maxillary sinus following a blow out fracture.
What is the grey line?
Separates the meibomian gland orifices from the eyelashes.
Good anatomical marker for apposition of a lacerated lid margin.
Careful repair of lid margin lacs are important especially at the upper lid (levator muscle, want to avoid a ptosis) and at the medial canthus (damage to the medial canthal ligament, which links the tarsal plate with the lacrimal crest in front of the lacrimal fossa, will disrupt the position of the lower lid and impair collection of tears by the eyelid puncta).
Canalicular laceration should be suspected when there is disruption of the medial canthus (particularly if lid margin is involved).
Main consequences of eyelid burns (whether thermal or chemical)?
1. Tissue loss and contracture
2. Corneal exposure (keep moist with chloramphenicol ointment and covered with a transparent cooking wrapper).
Skin and mucosal grafting may be necessary.
How best do you confirm the diagnosis of a blowout fracture?
Plain Xrays may show opacification of a sinus due to haemorrhage, and even a teardrop sign, but CT is still required to confirm.
Rx of a blowout fracture?
1. Systemic ABx (as is a compound fracture)
2. Enophthalmos may require surgical reconstruction (free trapped orbital tissue and cover bony defect).
Ocular motility disturbance frequently resolves as haemorrhage clears.
Name three types of superficial physical trauma to the eyeball.
1. Subconjunctival haemorrhage (looks serious but usually insignificant, except for when it masks a scleral perforation)
2. Corneal abrasion (appears green with fluorescein & blue light)
3. Foreign bodies (may lodge underneath upper lid or embed in cornea).
Conventional treatment of corneal abrasion?
Chloramphenicol ointment with or without a cycloplegic (cyclopentolate 1% or homatropine 2%) for comfort and occlusive padding for a day, followed by four times a day and chloramphenicol ointment for 4-7 days.
Removal of a foreign body lodged under the upper lid?
Removal is achieved by using a cotton-tipped bud, after instillation of benoxinate or amethocaine anaesthetic drugs.
Removal of embedded corneal foreign body?
Best removed with a hypodermic needle under magnification.
If the bevel of the needle is directed parallel to the surface of the cornea, so that the edge of the bevel strikes the edge of the object, needle perforation of the cornea is impossible.
Once FB has been removed, Rx is the same as for an abrasion, but intraocular penetration should be considered if a high velocity impact has occurred. Secondary infection is rare.
What is hyphaema?
Bleeding into the anterior chamber.
It always indicates that the eye has suffered sufficient (blunt) trauma to cause significant damage to any intraocular structure. Vision may be reduced to seeing hand movements but soon recovers as the blood clears. Usual to put pt to bed rest to avoid secondary haemorrhage, and await spontaneous clearance to examine whole eye for other damage.
The blood comes from the anterior chamber angle of the iris, so pupil abnormalities (usually dilation or ovalling) are common and may be permanent.
What is retinal commotio?
Traumatic oedema. Appears glistening white, resolves without sequelae.
Signs of rupture of the globe?
Vision is severely reduced and red reflex is absent, owing to hyphaema and vitreous haemorrhage.
Rupture of the globe is very rare.
A history of impact by a high velocity foreign body without obvious signs of trauma should alert the examiner to the possibility of what?
An intraocular foreign body.
What are the three main consequences of failure to identify an intraocular foreign body?
1. Short term: Intraocular infection
2. Medium term: retinal detachment
3. Long term: siderosis (iron-containing FBs, release ferrous ions into the eye, deposited in retina (permanent visual loss), the iris (heterochromia), trabecular meshwork (glaucoma).
Therefore, Xray or CT scan and ophthalmological referral are mandatory when this is suspected.
Rx of intraocular foreign body?
ABx and prompt removal, followed by expert care to maximise visual recovery.
If the lens is damaged by the FB, cataract is inevitable.
True or false: a severely injured eye may be chronically inflamed and uncomfortable, and may eventually require removal even if not completely blind.
What is sympathetic ophthalmitis?
An autoimmune reaction that attacks the healthy eye following perforation of the globe with exposure of brown uveal tissue (eg. corneo-scleral laceration, ie. with iris prolapse).
Sympathetic ophthalmitis can be prevented by early removal of the injured eye, which is especially indicated if it is completely blind (no light perception). Once this has begun, historically the prognosis has been poor, but treatment with newer immunosuppressants has improved the outcome.
True or false: corneal abrasion heals rapidly without scarring.
A corneal laceration is when you would worry: scarring causes astigmatism and opacity, which will impair vision even when no other structure is involved.