ocular manifestations of systemic diseases Flashcards

1
Q

RFs for diabetic retinopathy

A
  1. duration of DM
  2. level of metabolic control
  3. HTN, HLD, smoking, renal disease, obesity, pregnancy, anemia
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2
Q

findings in nonproliferative diabetic retinopathy

A

mild: microaneurysms

moderate:
1. dot and blot haemorrhages
2. flame-shaped haemorrhages
3. cotton wool spots
4. hard exudates
5. retinal edema

severe: (4-2-1 rule)
1. dark blot haemorrhages in 4 quadrants
2. venous beading/looping/segmentation inn >/= 2 quadrants
3. intraretinal microvascular abnormalities in >/= 1 quadrant

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3
Q

findings in diabetic maculopathy

A
  1. hard exudates
  2. edema in macula (cannot see macula or fovea)
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4
Q

findings in proliferative diabetic retinopathy

A

neovascularisation (NVD and NVE)

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5
Q

causes of visual loss

A
  1. diabetic maculopathy
  2. vitreous haemorrhage
  3. tractional retinal detachment
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6
Q

clinically significant macular edema (CSME)

A

at least 1 of:
1. Retinal thickening within 500 μm of macular centre
2. Hard exudates within 500 μm of macular centre with adjacent retinal thickening
3. ≥1 disc diameters of retinal thickening, part of which is within 1 disc diameter of macular centre

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7
Q

non surgical treatment for diabetic retinopathy

A
  1. Tight glycemic control (HbA1c≤ 7%,)
  2. control comorbidities / cardiovascular risk factors (HTN, HLD, renal disease) - regular exercise etc
  3. annual diabetic retinal photography (DRP)
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8
Q

medical treatment for diabetic retinopathy

A
  1. Laser photocoagulation:
    - Pan-retinal photocoagulation (PRP) for PDR or severe NPDR Complications: ↑ risk of macular edema
  • Focal or grid laser photocoagulation (clinically significant macular edema)
  1. Intra-vitreal injections of corticosteroids or anti-VEGF agents (CSME)
    - bevacizumab [Avastin]
    - ranibizumab [Lucentis]
    - aflibercept [Eyelea]
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9
Q

surgical treatment for diabetic retinopathy

A

Surgery (vitrectomy): tractional RD or non-clearing vitreous haemorrhage in PDR

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10
Q

classification of hypertensive retinopathy

A

grade 1: mild vein depression at AV crossing
grade 2: copper wiring, AV nipping
grade 3: haemorrhage, exudates, silver wiring
grade 4: same as grade 3 + disc swelling

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11
Q

management of hypertensive retinopathy

A
  • Treatment of underlying HTN
  • If patient previously undiagnosed, refer for assessment:

Grade 1 and 2: non-urgent referral
Grade 3: more urgent referral to eye
Grade 4 hypertensive retinopathy: medical emergency, immediate referral to ED for urgent BP control

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12
Q

what conditions is hypertensive retinopathy associated with?

A
  • Retinal artery occlusions: BRAO, CRAO
  • Retinal vein occlusions: BRVO, CRVO stasis, thrombosis, occlusion
  • Non-arteritic anterior ischemic optic neuropathy
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13
Q

signs in thyroid eye disease (commonly Graves)

soft tissue inflammation

A
  1. periorbital and lid swelling
  2. conjunctival hyperaemia and chemosis (conjunctival chemosis)
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14
Q

signs in thyroid eye disease (commonly Graves)

can see both inferior and superior sclera

A

proptosis

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15
Q

what do restricted extraocular movements cause?

A

binocular diplopia

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16
Q

order of extraocular muscles affected in thyroid eye disease

A

inferior rectus > medial rectus > superior rectus > lateral rectus

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17
Q

sight threatening complications of thyroid eye disease

A
  1. Compressive optic neuropathy
  2. Glaucoma
  3. Exposure keratitis with corneal dryness, ulceration and infection
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18
Q

how does thyroid eye disease cause optic neuropathy

A

oversized recti and orbital fat causing compartment syndrome at apex of orbit causing↓ vision, ↓ colour vision, RAPD, red desaturation

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19
Q

how does thyroid eye disease cause glaucoma

A

Glaucoma: contraction of extraocular muscles against intraorbital adhesions or orbital congestion due to ↑ tissue volume causing increased IOP

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20
Q

inx for thyroid eye disease

A
  • Bloods: free T4, TSH, anti-TSH receptor Ab
  • Radiological (CT, MRI): determine amount of soft tissue involvement, planning for surgical decompression
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21
Q

**

6 thyroid eye signs

A
  1. chemosis (red eyes)
  2. proptosis (see from side/top)
  3. exopthalmos (see bottom of sclera)
  4. lid retraction (see top of sclera)
  5. ophthalmoplegia (H - see double)
  6. lid lag
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22
Q

classical finding on CT orbit (axial, coronal)

A

enlargement of extraocular muscles that spare tendinous insertions as it’s infiltrative

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23
Q

treatment for thyroid eye disease

conservative

A
  1. lubricating eyedrops and tape eyelids shut at night for exposure keratopathy (mild cases)
  2. systemic immunosuppression with oral or IV steroids (more significant eye disease)
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24
Q

treatment for thyroid eye disease

non conservative, non surgical

A

radiotherapy

decrease periorbital inflammation refractory to medical immunosuppression

25
Q

treatment for thyroid eye disease

surgical

A

surgical orbital decompression

enlarge existing orbital space by removing bony walls (lateral wall in Caucasians, floor and medial wall in Asians but higher risk of diplopia) for severe proptosis, used when optic neuropathy threatens vision

26
Q

treatment for thyroid eye disease

rehabilitative

A

Rehabilitative:
1. squint Sx (in patients with myopathy causing significant diplopia) to improve ocular alignment and relieve diplopia
2. lid Sx (tarsorrhaphy to reduce exposure keratitis)

27
Q

ocular features of MG

A
  1. Ptosis
  2. Diplopia if extraocular muscles involved
28
Q

cardinal features of MG

A
  1. fatigability
  2. variability

symptoms fluctuate and worse twards end of day

29
Q

tests to demonstrate fatigability of lid in MG

A

prolonged upward or lateral gaze

30
Q

MG eye PE

A
  1. Cogan’s lid twitch
  2. Orbicularis oculi weakness: patient unable to bury eyelashes when asked to close eyes tightly (eye peek sign)

Cogan’s lid twitch: ask patient to look down then up, upper lid overshoots as eye looks up before settling down to ptotic position

31
Q

non ocular features in MG

A
  1. Bulbar symptoms:
    * fatiguable chewing
    * oropharyngeal muscles (dysphagia and aspiration, dysarthria)
    * soft palate (nasal dysphonia or hypophonia)
  2. Respiratory weakness
  3. Proximal limb weakness: difficulty washing hair, getting up from chair, climbing stairs
32
Q

diagnostic tests of MG

bedside

A
  1. IV edrophonium (Tensilon) test
  2. ice pack test (2min on closed eyelids)
  3. nap test

check if ptosis resolves

33
Q

necessary precautions when using IV edrophonium

A
  1. Cardiac, BP and PR monitoring for bradycardia and asystole
  2. resuscitation facilities
  3. IV atropine must be ready!
34
Q

MOA of edophonium

A

Acetylcholinesterase inhibitor competitively blocks AChE, ACh can’t be hydrolysed and
remains in NMJ at higher concs for longer time

35
Q

diagnostic tests of MG

blood tests

A

Ab to Ach receptors

36
Q

diagnostic tests of MG

electrophysiological studies

A
  • Repetitive nerve stimulation
  • Single fibre electromyography (SFEMG, most sensitive test)
37
Q

repetitive nerve stimulation

A

decremental response in compound muscle action potential amplitude over time

38
Q

single fibre electromyography

A

simultaneous recording of action potentials of 2 muscle fibres innervated by same motor axon: ↑ jitter

39
Q

diagnostic tests of MG

imaging

A

CT or MRI of anterior mediastinum

15% have thymoma

40
Q

management of MG

medical

A
  1. acetylcholinesterase inhibitor (e.g. oral pyridostigmine, neostigmine)
  2. prednisolone
  3. cyclosporine
  4. plasmapheresis
  5. IV human immunoglobulin
41
Q

management of MG

surgical

A

thymectomy

42
Q

opportunistic eye infections and tunmours in AIDS

A
  1. kaposi’s sarcoma
  2. molluscum contagiosum
  3. herpes zoster
  4. syphilis
  5. cryptococcus
  6. toxoplasmosis
43
Q

coommon vision-threatening infection in AIDS

A

CMV retinitis

44
Q

sx of CMV retinitis

A
  • Initially asymptomatic
  • floaters or painless loss of central or peripheral vision
45
Q

progression of retninitis in CMV reinitis

A

starts in mid-periphery and progresses in brushfire pattern producing areas of necrosis, scarring and atrophy

46
Q

findings on fundoscopy

CMV retinitis

A

cheese and ketchup appearance: thick white infiltrates with retinal haemorrhages

47
Q

mx of CMV retinitis

A

Mx concurrently with ID (immune status needs to be optimised with HAART (anti-retroviral therapy)):

  • Disseminated CMV: IV ganciclovir, foscarnet or cidovir
  • Ocular Mx: intravitreal injection of ganciclovir or foscarnet, implant ganciclovir into vitreous cavity
  • Oral valganciclovir (cost significantly higher)
  • Closely monitor patient for retinal detatchments or recurrence of CMV retinitis
48
Q

commonest RA ocular manifestation

A

keratoconjunctivitis sicca (dry eyes)

49
Q

ocular involvement in RA

cornea involvement

A
  1. Peripheral ulcerative keratitis: significant corneal thinning.
    Goals of Tx:
    * minimise amount of inflammation with systemic immunosuppressants
    * prevent infections with topical abx
    * promote healing of ulcers with lubricants
  2. Contact lens cornea
  3. Cornea melt
50
Q

ocular manifestations in RA

non cornea involvement

A

episcleritis and scleritis

51
Q

episcleritis in RA

A
  1. simple
  2. nodular - discrete elevated area of inflammed episclera
52
Q

scleritis in RA

A
  1. diffuse non-necrotising scleritis
  2. necrotising anterior scleritis w/o inflammation (scleromalacia perforans)
  3. necrotising anterior scleritis a/w corneal melt
53
Q

ocular manifestations of SLE

A
  • Eyelid erythema or discoid lesions
  • Keratoconjunctivitis sicca
  • Keratitis with peripheral corneal thinning
  • Scleritis
  • Retinopathy: mild to severe (vessel occlusive disease or retinal vasculitis)
  • Neuro-ophthalmic complications e.g. optic neuritis, ischemic optic neuropathy
54
Q

grade 1 htn retinopathy

A

grade 1: mild vein depression at AV crossing

55
Q

grade 2 htn retinopathy

A

grade 2: copper wiring, AV nipping

56
Q

grade 3 htn retinopathy

A

grade 3: haemorrhage, exudates, silver wiring

57
Q

grade 4 htn retinopathy

A

grade 4: same as grade 3 + disc swelling

58
Q

grade 4 htn retinopathy

A

grade 4: same as grade 3 + disc swelling