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Emergency Medicine > Opthalmology > Flashcards

Opthalmology Flashcards

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1
Q

What are 4 signs/symptoms of a retrobulbar hemorrage?

A
  1. Proptosis (forward displacement of eye)
  2. Decr. visual acuity
  3. Decr ROM
  4. Incr ocular pressure (normal 10-20 mmHg)
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2
Q

Why is a retrobulbar hemorrhage an emergency?

A

Incr pressure results in central retinal artery and optic nerve ischemia. Needs to be decompressed.

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3
Q

What is the treatment for a Retrobulmar hemorrage/hematoma?

A
  1. Carbonic anhydrase inhibitor
  2. Topical BB (Timolol)
  3. Mannitol 1-2 g/kg
  4. Lateral Canthotomy and cantholysis
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4
Q

Why is alkali liquid to the eye more damaging than acid?

A
  • Alkali causes a liquefaction necrosis that penetrates and dissolves tissues.
  • acidic exposure coagulation necrosis and the precipitation of tissue proteins limits the depth of the injury
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5
Q

What is the treatment of an open globe rupture?

A
  1. NPO +/- analgesia, anti-emetics
  2. Elevate HOB, protect eye
  3. Tetanus
  4. Abx (Ceftriaxone, gentamycin, Vancomycin)
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6
Q

What is a chalazion?

A

A blockage of one of the Meibomian glands within the tarsal plate. Is not infectious. Self limiting (warm compress).
- Persistent ones can have optho incise it.

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7
Q

What is a Stye?

A 
Aka.  Hordeolum
External Hordeolum ("Stye")
- Involvement of zeis glands
Internal Hordeolum
- Involvement of meibomian glands
Treatment
- Warm compresses
- May use Erythromycin ointment TID or Cephalexin 500mg BID x 7 days
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8
Q
  1. where is aqueous humor made?
  2. What its its purpose?
  3. What is its pathway
A
  1. Made by the ciliary body
  2. Gives nutrients to the lens and central cornea (they lack blood supply). It also maintains the anterior chamber
  3. Made by ciliary body, goes into posterior chamber (posterior to the iris) and out through pupil.
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9
Q

What is the different between open and closed angle closure glaucoma?

A
  1. Open - there is something wrong with the trebecular meshwork and the aqeuous humor doesnt drain, increasing the ocular pressure. the angle between the iris and cornea is maintained
  2. Closed angle - the angle between the iris and cornea closes off quickly and pressure buildup occurs fast. Is an emergency.
    - Aqueous humor is made by ciliary body as usual, but cannot enter through pupil into anterior chamber. Pressure builds and ultimately pushes the iris up causing an acute angle between the cornea and iris (closing off the trabecular meshwork and canal of Schelmm).
    - Classically occurs when pupil really dilated.
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10
Q

On exam what do you seen in angle closure glaucoma (open mostly)?

A
  1. High IOP >20 mmHg
  2. Incr cup to disc ratio (cup gets bigger due to loss of nerves)
  3. Loss of peripheral vision
  4. Fixed- dilated pupil
  5. Steamy cornea
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11
Q

What are risk factors for closed angle closure glaucoma?

A
  1. shallow chambers
  2. small eyes
  3. Asian
  4. Big Cataracts
  5. Dilation
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12
Q

What is the treatment for closed angle closure glaucoma?

A
  1. Timolol drops (0.5%) works within 30-60 min
  2. Carbonic anhydrase inhibitors (azetazolamide)
  3. Topical alpha-agonist (Apraclonidine 1% 1gt once)
  4. Prednisolone 1% 1 gt q 15 min
  5. Pilocarpine 4% 1gt then q15 min (IOP>30mmHg)
  6. Surgical release

OR

  1. Block production of aqueous humor:
    - Topical BB: Timoptic 0.5% 1 drop q30min x 2
    - Carbonic anhydrase inhibitor: Acetazolamide 500mg IV/PO/IM, then 250 q6h
    - Alpha-2 agonist: Apraclonidine 1 drop q30min x 2
  2. Reduce volume of vitreous:
    - PO Osmotic agents: Glycerol 1mL/kg po, Isosorbide 100mg po
    - IV osmotic agents: Mannitol 1-1.5g/kg IV
  3. Facilitate outflow of aqueous humor:
    - Topical pilocarpine
    - Blue eyes 2% 1 drop q15min for 1-2 hrs
    - Brown eyes 4% 1 drop q15min for 1-2 hrs
  4. Definitive Care
    - Referral to ophthalmologist for iridotomy
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13
Q

DDX acute painless vision loss (8)

A
  1. Central retinal artery occlusion
  2. Central retinal vein occlusion
  3. Retinal detachment
  4. Temporal arteritis
  5. Amaurosis fugax (TIA)
  6. Vitreous hemorrhage
  7. Macular degeneration (usu slow onset)
  8. Optic neuritis (MS)
  9. Papilledema
  10. Opthalmic migraine
  11. Neuro-opthalmologic disease
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14
Q

What is an important CI to diamox that we need to consider in the context of patient with hyphema?

A

CI in Sickle cell patient. Can cause sickling of RBC that can further clog up the trabecular meshwork.

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15
Q

What is the first sign of optic nerve pathology?

A

Color desaturation

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16
Q

On fundoscopic exam: RAPD, pale retina with cherry red spot (fovea) what is the dx?
What is the treatment

A

Central retinal artery occlusion
- is an emergency. usual embolic in origin.

Treatment: Anterior chamber paracentesis, globe massage, lower IOP

17
Q

What do you see on fundoscopy with central retinal vein occlusion?

A

Blood and thunder hemorrages. Get edema, hemorrage and vascular leakage.

18
Q

What is the ddx of monocular diplopia?

A
  1. Refractive error in cornea, lens, vitreous(most common)
  2. Dislocated lens
  3. Iridodialysis (tearing of iris from ciliary body)
  4. Malingering
19
Q

What is the ddx of biocular diplopia?

A
  1. Cranial nerve palsy III,IV, VI (most common)
  2. Orbital floor # causing entrapment
  3. Hematoma
  4. Orbital cellulitis/abcess
  5. Thyroid disease/Graves
  6. Aneurysm
  7. Tumor
  8. MS
  9. Myesthenia Gravis
  10. Stroke (usu have other neuro deficits)
  11. Wernickes encephalopthy
20
Q

What is the condition you can get from blunt injury to the eye?

A

Commotio retinae

  • can be associated with hemorrages, retinal tears.
  • May have severe decr in visual acquity. On its own has a good prognosis.
  • Thought to be due to photoreceptor disruption
21
Q

What is the management for globe laceration or rupture?

A
  1. Anti-emetics
  2. Antibiotics (3rd gen cephalosporin, Vancomycin)
  3. Tetanus
  4. Analgesics, morphine.
  5. Protect with eye shield
  6. Elevate HOB, NO pressure readings
  7. Optho consult
22
Q

What is one of the only contraindications to lateral canthotomy?

A

Globe rupture.

23
Q

What are signs and symptoms of a cranial nerve 3 palsy or complete lesion? (5)

A
  1. Diplopia
  2. Limited EOM
  3. Eye looks laterally and down (down and out)
  4. RAPD
  5. Ptosis
24
Q

What structures do you cut during a lateral canthotomy?

A
  1. Inferior lateral canthal tendon

2. Superior lateral canthal tendon if above doesnt release.

25
Q

What do you see in CRAO (central retinal arterial occlusion) on fundoscopy?

A
  1. retinal edema
  2. cherry red spot
    (caused by perfused choroid showing through thinner fovea)
  3. Pale retina
26
Q

What is considered an elevated IOP?

A

> 20 mmHg

27
Q

What is the ddx for elevated IOP?

A
  1. Acute angle closure glaucoma
  2. Retrobulbar hemorrage
  3. Retrobulbar space occupying lesion
  4. Suprachoroidal hemorrhage
  5. Trauma (can be seen in hyphemas)
28
Q

What are some causes of uveitis (iritis +/-iridocyclitis (inflammation in vitreous cavity also)

A
  1. Trauma
  2. Infection
  3. JRA, RA
  4. Sarcoidosis
  5. Ankylosing spondylitis
29
Q

When are mydriatic and cycloplegic agents contraindicated?

A

In acute glaucoma

30
Q

In sickle cell patients with high IOP what can you give?

A
  1. Timolol drops

2. Oral Methazolamide 50 mg instead of acetazolamide apparently. but its still a carbonic anhydrase inhibitor..

31
Q

In blunt trauma resulting in a hyphema, what is the management?

A
  1. Analgesia, anti-emetics
  2. If high IOP, azetazolamide
  3. Cycloplegic to prevent repetitive motion of the iris (topical homatropine)
  4. Eye shield at least for sleep.
32
Q

Foreign body treatment after removal?

A
  1. Antibiotic ointment
  2. AT (artificial tears)
  3. F/U optho esp if rust ring (doesn’t need to be removed in ED)
33
Q

Chemical burn to eye treatment/management?

A
  1. Irrigation >40 min esp if alkali

2. Can d/c if pH =7 and no VA changes, consult optho

34
Q

What are some clinical signs of globe rupture?

A
  1. Deformed globe (obvious)
  2. Decr VA
  3. Decr EOM
  4. Deformed iris or pupil
  5. Hyphema
  6. RAPD or no pupil reaction
  7. Low IOP but dont measure it!
35
Q

What is the treatment for bacterial conjunctivitis?

A
  1. Topical polymyxin B trimethoprim in infants due to more staph
  2. If CL use, flouroquinolone

Emergency Medicine (39 decks)

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