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Retinovascular Disease > Central And Branch Retinal Artery Occlusions > Flashcards

Central And Branch Retinal Artery Occlusions Flashcards

1
Q

What causes the occulsions?

A

Obstruction is caused by an atheroma which is an accumulation of fatty deposits in lining of the artery. Atheroma leads to the formation of thrombosis which is deposits in the artery. Calcium, cholesterol and platelet fibrin

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2
Q

Risk factors of crao?

A

Smoking, age, high cholesterol, diabetes, hbp

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3
Q

Where can obstructions occur?

A

They can occur at the central artery or an individual branch

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4
Q

At the central retinal artery, where does the thrombus develop?

A

Develops at the level of the lamina cribrosa

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5
Q

What happens if the thrombus doesn’t develop at central retinal artery?

A

It could develop at arteries near the heart e.g. Internal carotid artery and detaches and travels via the arterial system and then can come lodged within retinal artery

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6
Q

What’s another word for thrombus?

A

Embolus

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7
Q

Sx of crao

A

Sudden painless loss of vision

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8
Q

Sx of branch (brao)

A

Loss of vision in a quadrant and vessels don’t cross the midline

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9
Q

Sx of peripheral brvo

A

Unnoticed vision loss due to overlapping fields

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10
Q

Explain amaurosis fugax

A

Embolus restriction of arteriolar blood flow

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11
Q

Sx of amourosis

A

Sudden monocular loss of vision affecting the whole visual field for several minutes and doesn’t include any other sx

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12
Q

What’s the differential diagnosis of amaurosis fugax

A

Ischemic attack and giant cella arthritis

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13
Q

Signs of occlusion (BRAO/CRAO)?

A

CRAO: poor va, cherry spot macula, +rapd, whitened and cloudy retina with narrow vessels

BRAO: no cherry spot, white retina at only the sector that’s affected, narrow vessels, +RAPD, emoblysm may be seen

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14
Q

What causes the cherry spot?

A

The choriodal vessels shining through the pale retina at the thinnest part of the retina which is the fovea

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15
Q

What is a cilloretinal artery?

A

Additional blood supply from the posterior cillary artery and is not affected by obstructions of the cent ret artery. This only supplied the region between the macula and optic disc. VA might be reasonable and that region will have normal colour

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16
Q

What happens with a crao with a cillioretinal artery?

A

Blood flow from optic disc and macula is preserved because the cillioretinal artery isn’t affected by the occlusion in the cent ret artery

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17
Q

Explain what would occur when an embolus is blocking the artery that serves the macula region?

A

Va will be reduced and this area will be pale and cloudy and the embolus may be visible. It may also show a cherry spot at the macula

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18
Q

Explain incidence and sx of giant cell arthritis

A

Severe permanent bilateral vision loss. Features include pain, jaw claudication, fever/malaise and dip

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19
Q

Explain the ischemia procedure

A

Sudden and prolonged decrease in oxygen. The retina can’t withstand lack of oxygen which leads to ischemia which is cell death

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20
Q

Can you restore vision in occulsions

A

Yes if it’s within 4 hours. One way is to have a firm, intermittent massage through a closed eye lid for 15 mins which helps promote changes in blood and dislodge an embolus. 2nd option-breathe into a paper bag to increase co2 levels and induce vasodilation

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21
Q

What is the recall/referral for occulsions and amaurosis

A

Urgent same day emergency

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22
Q

What is the management for occulsions

A

The prognosis is poor and va will barely be useful but management is for addressing px risk or cardiovascular diseases which reduces the risk of developing occulsions in the fellow eye

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23
Q

What will the ophthalmologist manage?

A

They will monitor the development of neovasc

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24
Q

Explain neovascularisation and it’s treatment

A

This is where there’s a growth or abnormal and new leaky vessels which are located on top of the NFL and obscure all the layers under. This is due to a protein release of VEGF that which act on the VEGF receptors and activate new leaky vessels in an attempt to vascularise ischemic tissue. If untreated the px is at risk of iris neovasc which could then lead the px to get secondary glaucoma

25
Q

What is the treatment of neovasc

A

It’s a laser pan retinal photocoagulation (prp) that destroys the damaged retinal tissue and if untreated could lead to glaucoma

26
Q

What is the prevalence of central and branch retinal vein occulsion?

A

CRVO-16.4 mill and 0.8/1000
BRVO- 5x more common and 4.42/1000
Superior temporal is the most common location for brvo

27
Q

What are the risk factors for vein occulsions

A

Age, hbp, dm, cholesterol, smoking, open angle glaucoma

28
Q

What causes vein occulsions

A
  • Sheath covering arteriole and venue
  • Thickening wall because of arteriosclerosis leads to compression of the vein
  • damage to the wall due to atherosclerosis causes a loss of endow cells which leads to a thrombus forming leading to an occlusion
29
Q

Where do BRVOs occur mostly

A

They occur at av crossings–thickening of the vessel wall due to arteriosclerosis leads to compression of the venule

30
Q

Where are the most av crossings?

A

Supertemporal = highest level of av crossings

31
Q

What does branch occulsion refer to

A

It refers to more than one of the 4 quadrants arising from the cent vein

32
Q

Describe an inferior branch

A

Affecting 2 quadrants below or above the horizontal Ralph and doesn’t cross the hz midline

33
Q

Explain the superior temporal occlusion

A

Doesn’t cross the hz midline

34
Q

What causes retinal

Hypoxia

A

Occulsion disrupts the drainage which leads to an increase of pressure and the pressure is pushed back from the vein via the venules to the capillaries which may rupture. Due to this there’s an extensive haemorrhage. This then leads to stagnation of the blood which means oxygenated blood can’t be delivered to ret tissue which causes hypoxia

35
Q

Sx of CRVO/BRVO/

A

Sudden painless monocular vision loss for CRVO. In BRVO there will be sectoral vision loss

36
Q

What causes the shape of the occulsions?

A

It’s driven by vessel distributions and depends on the regions of the retina that’s served by the effected branch

37
Q

In BRVO, will the peripheral retinas have sx?

A

No

38
Q

What is retinal ischemia?

A

Reduced retinal perfusion and capillary closure leading to hypoxia

39
Q

What will occur when ischemia is within the macula region

A

Permanent visual impairment

40
Q

What causes reduced vision in non-ischemic CRVO?

A

Depends on the degree of macula oedema and ea he from 6/60 and 6/30

41
Q

In non ischemic CRVO what will pupil reactions be like?

A

Normal or show a mild RAPD

42
Q

What will the fundus exam show in a non-ischemic CRVO?

A

Dilation and tortuousity of the veins and flame/dot/blot haemorrhages and breakdown of the BRB will cause oedema

43
Q

What features in ischemic and non-ischemic CRVO?

A

Cotton wool spots

44
Q

Discuss cotton wool spots?

A

Indicates areas is retinal ischemia which led to infarction of tissue (cell death)

45
Q

Signs of ischemia

A

Significant RAPD and poor va maybe even counting fingers

46
Q

In CRAO/BRAO why does ischemia arise?

A

Results as a direct result of occulsio leading to sudden and severe lack of perfusion to retina. Other reason for ischemia could be occulsions affecting the drainage

47
Q

What do capillaries become after widening?

A

Venules

48
Q

What occurs with drainage failure with ischemia?

A

Drainage failure in veins leads to increased pressure and when the pressure is high enough, the brb breaks and liquid is transferred through the vessel wall leading to haemorrhaging and exudates and oedema. Rising pressure outside the capillary wall slows the outflow of oxygenated blood going into ret tissue that need it leading to ischemia

49
Q

What happens when a vein occulsion becomes ischemic?

A

It can take weeks or days but artery occulsions have immediate and severe ischemia

50
Q

What distinguishes the ischemic vein occulsions?

A

Optic disc swelling and cotton wool spots “blood and thunder fundus”

51
Q

What’s the difference of prevalence in non-ischemic and ischemic?

A

Non ischemic: more common (75%)

Ischemic: less common

52
Q

What’s the difference in va in non ischemic and ischemic?

A

Non ischemic: impaired but better than 6/60

Ischemic: poor va

53
Q

Difference in pupils between non ischemic and ischemic?

A

Non ischemic: normal or mild RAPD

ischemic: significant RAPD

54
Q

Difference in signs between non ischemic and ischemic

A

Disc swelling and cotton wool spots. For ischemia it’s the same signs as non ischemia but more severe

55
Q

Is oedema present in non ischemic or ischemic?

A

Rarely for non ischemic and common for ischemics

56
Q

What’s the prognosis between ischemic and non ischemic?

A

For non ischemic the prognosis is good but very poor in ischemic due to involvement of the macula caused by hypoxia.

57
Q

Is vein occulsion unilateral or bilateral?

A

Unilateral

58
Q

Is diabetic retinopathy unilateral or bilateral?

A

Bilateral

59
Q

What causes ischemia to have a poor prognosis?

A

Irreversible damage to the macula reduces the prognosis of ischemia

Retinovascular Disease (4 decks)

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