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NBEO STEP 1 > ocular disease > Flashcards

ocular disease Flashcards

1
Q

alkali chemical burn

A
  • This are the most common chemical burns because more accessible. ie. cleaning agents, fertilizer (ammonia); anything with OH, fireworks, flames, cement ( and cement like things), mouthwash and airbag residue
  • worse prognosis - raise tissue pH , leads to break down of fatty acids in the cell membrane - more alkali solution can penetrate
  • takes about 1 min to penetrate
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2
Q

acidic chemical burn

A

hydrofluoric acid ( glass polisher, industrial cleaner, rust removal), sulfuric acid ( fertilizer batteries) nitric acid ( fertilizer, explosives) etc

less common and less severe compared to alkali chemical burn

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3
Q

what are signs and symptoms of someone with a chemical burn?

A

Signs:
- corneal ( SPK - sloughing off epithelium)
- injection ( conj, ciliary ( ie. ACA branches injected)
- conj: chemosis and injection , hemes
-A/C rxn
- high IOP
- blanching/ turning white sclera/limbus = BADDD - means ischemia

symptoms:
- pain ( corneal nerves/ conj nerves)
- decreased vision/ photophobia ( cornea affected - spk etc)
- FBS (chemosis etc)
- tearing
- blepharospasm

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4
Q

what is the most common cause of alkali burns ?

A

calcium hydroxide

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5
Q

fluorescein dye

A

water soluble - dissolves in aqueous Layer of the tears

helps us look for corneal epithelial defects (ie. stains defects) and tear film quality( lacrimal lake, tear meniscus, TBUT

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6
Q

how do you treat a chemical burn

A

irrigate till you reach a pH of 7.0 , ( check pH every 15-30 mins)

AT’s, topical antibiotic, steroid once epithelium is healed if needed?, cyclo, amniotic membrane

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7
Q

Steroids- why should you be careful?

A

overuse can lead to corneal melting, taper off

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8
Q

Corneal abrasion signs and symptoms

A

pain - extensive network of corneal epithelium nerves
FBS
photophobia/ decreased VA (depending on location)
A/C rxn
miotic pupil - due to reflex cornea sends signal to iris

signs: staining of defect

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9
Q

How long does it take for a corneal abrasion to heal?

A
  • small abrasions - heal in a few hours
  • larger abrasions can take overnight
  • peripheral lesions heal more slowly because limbal stem cells can be affected

remember entire corneal regeneration takes 7-14 days. see phys notes on how the cornea regenerates

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10
Q

see linear vertical corneal scratches

A

check upper eyelid for foreign body
- prior to foreign boy removal check VA

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11
Q
A

Rust ring caused by a metallic foreign body

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12
Q

recurrent corneal erosion

A

this is a repeated spontaneous disruption of the corneal epithelium.

Occurs due to improper formation of hemidesmosomes ( ie. anchor basal cells to the basal lamina) or abnormal basement membrane that is not properly attached to the corneal storm ( EBMD).

can also be age related because as we age epithelial cells secrete more basal lamina - penetration of anchoring fibrils causes epithelium to be loosely attached to stroma

MMP’s = enemies can mess with the healing process - use doxy to help with healing

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13
Q
A

Seidel sign - shows if a wound leak exists

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14
Q

signs of a ruptured globe/ penetrating injury

A

laceration,
hemorrhage, hyphema
EOM restrictions,
low IOP, Seidel’s sign,
commotio retinae,
RD/ choroidal rupture

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15
Q

Hyphema causes

A
  1. trauma
  2. disease: sickle cell (recurrent hyphen), clotting disease
  3. idiopathic ( using any blood thinners? NSAIDS, apirin, warfarin, clopidogrel, dipyradale)
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16
Q

How does a hyphema occur?

A

due to injury of iris or CB

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17
Q

Treatment of hyphema

A
  • do not do gone/ scleral depression up to 1 month post injury ( can cause rebreeding = worse)
  • B scan to check for RD
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18
Q
A

8 ball hyphema: black hyphema covering 100 % of the anterior chamber

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19
Q

microhyphema

A

can only see RBCs suspended in AC with a slit lamp

20
Q

uses of a B scan

A
  • when opacification/ something blocking view of posterior segment
  • ONH drusen
  • distinguishing between a choroidal nevus vs melanoma ( hallow inside)
21
Q
A

due to posterior pigmented epithelium of iris hitting lens

22
Q

See a vossius ring + hyphema

A

means trauma!!!

23
Q
A

subluxation of a lens
# 1 cause = TRAUMA
- another = Marphans

24
Q
A

= iridodialysis = separation of iris root from CB

  • NOTE: iris root = thinnest part of iris , thickest = collarette
25
Q

corneal blood staining

A

can occur as a result of hyphema, rebleeds, High IOP
- the endothelial cells are compromised, allowing hemoglobin and hemosidern to enter the storma.

26
Q

hyphema secondary effects

A
  • corneal blood staining
  • glaucoma : high IOP due to RBC blocking TM (ie. decreasing outflow) - to prevent this elevate head at 30 degrees so blood cells settle inferiorly.
27
Q

Idiopathic hyphema - what to do

A
  1. ask about blood thinners
  2. CBC + prothrombin time/partial thrombopastin time (PT/PTT)
  3. sickle cell screening ( AA and Mediterraneans)
28
Q

What to do if you suspect a metal foreign body?

A

DO NOT ORDER MRI

29
Q

foreign bodies that can cause inflammation

A

iron, steel, copper, vegetable matter

30
Q

inert foreign bodies

A

glass, stone, precious metals, plastic

can stay in the eye long periods without causing inflammation

31
Q

blow out fracture

A

floor fracture
- floor is made of “ my Pal Z’s on the floor”
- maxillary, palatine, zygomatic
- weakest bone = maxillary
- thinnest bone = ethmoid

NOTE: susceptible to sudden increase in IOP,

32
Q
  • what sinus is below the maxillary bone?
A

maxillary sinus

33
Q
  • if the patient has trauma to the globe, where is the eye most likely sitting in
A

maxillary sinus because the floor is the most likely one to fracture

34
Q
  • 3 things that run along the floor and both these things can be affected with a floor fracture
A

IR (inferior rectus), V2, IO

Remember V1 is above the eye and V2 is below the eye

35
Q

Number of branches in V2 and how a orbital fracture can affect them.

A

2 – infraorbital and zygomatic
 If the infraorbital nerve is affected – can have a loss of sensation in the cheeks ( when comparing the 2 cheekbones – can have hypoesthesia in that area)
 If the IR is affected and trapped – the patient has trouble looking up

36
Q

forced duction test

A

(+) means that there is restriction
(-) means that eye can move

37
Q

sign of a orbital fracture

A

creptius = crackling when palpation of the medial orbital area or after nose blowing

38
Q

how do you limit the risk of an orbital infection following orbital fracture?

A

do not sneeze

39
Q

when do you get a positive forced duction test?

A

orbital floor fracture

brown syndrome ( affects SO muscle/ tendon - can be tight/ too short)

Grave’s opthalmopathy

40
Q

what is a negative forced duction test associated with?

A

cranial nerve palsy

41
Q

Commotio retinae

A

when the photoreceptor outer segments are disrupted and the RPE is damaged. — retina is edematous/ white ( takes hours to develop)

result of trauma, vitreous hitting back of the eye

no treatment observe (3-4 weeks)

called Berlin’s edema if at macula = retinal concussion (mild), retinal contusion ( if with VA loss and severe)

42
Q

purtscher’s retinopathy

A

Has to do with chest compression trauma

see CWS, hemes, educates

43
Q

what else can cause putscher’s like retinopathy?

A

acute pancreatitis
renal failure
long bone fractures

44
Q

choroidal rupture

A

can be caused by trauma

usually seen in the temporal post pole

can cause CNVM

45
Q

conditions that can cause CNVM

A

ie. break in Bruch’s ie. PED
C - choroidal rupture
H - histo ->. choroiditis
B - bests -> RPE degen due to lipofusion accumulation
A - angioid streaks -> decrease elastin ( middle layer of Bruch’s)
L - laquer cracks - > stretch
A - AMD - drusen accumulates in the inner collagenous zone of Bruch’s
S - Scar

46
Q

eyelid ecchymosis

A

= black eye ie. blood vessels leading in subcutaneous
tissue

NBEO STEP 1 (14 decks)

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