Ocular infections and tumours

Question 1

Features and causes of preseptal (peri-orbital) cellulitis (6)

Answer 1

anterior
more common and less serious than orbital cellulitis
can rarely progress to orbital cellulitis
causes: trauma/laceration, insect bites, URTI.

Question 2

Presentation of preseptal cellulitis (4)

Answer 2

NO PROPTOSIS
swelling, redness and warmth
fever and malaise
ptosis

Question 3

Mx of preseptal cellulitis (2)

Answer 3

most need admission for 24h

co-amoxiclav

Question 4

Features of orbital cellulitis (2)

Answer 4

spread via paranasal air sinuses

mainly affects children

Question 5

Presentation of orbital cellulitis (6)

Answer 5

rapid onset orbital swelling>proptosis

opthalmoplegia: severe swelling can>muscle compression; can also cause cavernous sinus thrombosis

lid swelling/redness/pain

blurred vision

may have RAPD/decreased pupillary response due to optic nerve compression

fever

Question 6

pathogens involved in orbital cellulitis (4)

Answer 6

staph aureus
strep pneumoniae
strep pyogenes
strep milleri

Question 7

Ix in orbital cellulitis

Answer 7

Monitor:

• obs
• vision
• movement
• colour vision

Question 8

complications of orbital cellulitis (2)

Answer 8

blindness from optic nerve compression

intracranial spread

Question 9

Rx of orbital cellulitis (7)

Answer 9

IV Abx: cefotaxime+metronidazole+/-vancomycin

may need surgery if:

• orbital/sinus collection on CT
• no response to Abx
• decreased acuity
• atypical picture (Dx biopsy)

Question 10

Presentation of herpes zoster opthalmicus (12)

Answer 10

• pain and neuralgia in V1 dermatome (forehead and eyes) before blistering rash
• visual loss/keratitis
• scleritis/episcleritis
• iritis
• limbic lesions
• pre-auricular lymphadenopathy
• purulent conjunctivitis
• optic atrophy
• CN palsies
• pupillary distortion
• nose tip involvement (hutchinson’s sign): involvement of nasociliary branch of Vth nerve>globe more likely to be involved
• can cause pseudodendritic ulcer (no bulbs at end of “branches”)

Question 11

Rx of herpes zoster opthalmicus (2)

Answer 11

oral antivirals:

• aciclovir (hepatitis, renal failure)
• ganciclovir (vomitting)

Question 12

long term consequence of herpes zoster opthalmicus and Rx (3)

Answer 12

post-herpetic neuralgia

Rx w. gabapentin and amitriptyline

Question 13

Features of endopthalmitis (2)

Answer 13

infection of the inner coats of the eye

can occur after any surgery/trauma penetrating the eye.

Question 14

Presentatino of endopthalmitis (5)

Answer 14

pain
inflammation/redness
visual loss
corneal injection
hypopyon if severe

Question 15

most common intra-ocular tumour in >50yrs

Answer 15

lymphoma

Question 16

Features of retinoblastoma (4)

Answer 16

most common ocular malignancy in children
presents at 3mo-3yrs
Auto-D inheritence; 80% penetrance
secondary malignancies: osteosarcoma, rhabdomyosarcoma

Question 17

Signs of retinoblastoma (2)

Answer 17

strabismus

leukocoria (white pupil)>absent red reflex

Question 18

Rx of retinoblastomas (6)

Answer 18

• try not to remove eye to preserve sight
• chemotherapy if bilateral
• enucleation (remove eye, leave muscles) if large
• opthalmic plaque brachytherapy: carries lower risk of causing other ca.
• external beam radiotherapy
• cryotherapy or transpupillary thermotherapy for small tumours.