Infectious Eye Diseaes

Question 1

What is preseptal cellulitis?

Answer 1

Infection of soft tissue anterior to orbital septum

Question 2

Aetiology of preseptal cellulitis?

Answer 2

Usually follows periorbital trauma or dermal infection

Question 3

Rx preseptal cellulitis?

Answer 3

-Systemic ABx e.g. amoxycillin-clavulanic acid

Question 4

Suspected pathogens in preseptal cellulitis?

Answer 4

H. influenzae in children; S. aureus or Strep in adults.

Question 5

What is orbital cellulitis?

Answer 5

OCULAR & MED EMERGENCY

-Inflammation of orbital contents posterior to orbital septum

Question 6

Who is predisposed to orbital cellulitis?

Answer 6

-Children, elderly and immunocompromised.

Question 7

Aetiology of orbital cellulitis?

Answer 7

Usually secondary to sinus / facial / tooth infections or trauma. May arise from pre-septal cellulitis.

Question 8

Treatment orbital cellulitis?

Answer 8

• Admit
• 2 x blood cultures
• Orbital CT
• IV ABx (ceftriaxone + vancomycin)
• Surgical drainage of abscess and close follow up

Question 9

Complications of orbital cellulitis?

Answer 9

• Optic nerve inflammation
• Cavernous sinus thrombosis
• Meningitis
• Brain abscess with possible loss of vision and death

Question 10

Clinical features of pre-septal cellulitis?

Answer 10

• May have fever
• Mod-severe lid oedema
• Normal vision
• No RAPD
• Mod leukocytosis
• May have skin infection

Question 11

Clinical features of orbital cellulitis?

Answer 11

• Fever
• Severe lid oedema
• Conjunctival infection
• Marked chemosis
• Proptosis
• Pain on eye movement
• Decreased ocular mobility
• Diminished vision
• +/- RAPD
• Marked leukocytosis
• Elevated ESR
• May have sinusitis, dental abscess

Question 12

What is dacryocystitis?

Answer 12

Acute or chronic infection of the lacrimal sac. Most commonly due to obstruction of nasolacrimal duct.

Question 13

Cause Herpes Simplex Keratitis?

Answer 13

Usually HSV type I (90% population are carriers).

Question 14

Triggers of herpes simplex keratitis?

Answer 14

Stress, fever, sun exposure, immunosuppression.

Question 15

Clinical features of herpes simplex keratitis?

Answer 15

• Pain, tearing, foreign body sensation, red eye, +/- decreased vision, eyelid oedema.
• Corneal hypoesthesia

Question 16

Appearance herpes simplex keratitis?

Answer 16

Dendritic (thin and branching) lesion in epithelium that stains with fluorescein.

Question 17

Complications of herpes simplex keratitis?

Answer 17

• Corneal scarring
• Chronic interstitial keratitis due to penetration of virus into stroma
• 2” iritis, 2” glaucoma

Question 18

Treatment herpes simplex keratitis?

Answer 18

• Topical antiviral (e.g. trifluridine)
• Systemic antiviral (e.g. acyclovir)
• Dendritic debridement
• NO STEROIDS initially

Question 19

What is Hutchinson’s sign?

Answer 19

If tip of nose is involved (nasociliary branch of V1) then eye will be involved in ~75% of cases.
No nasal involvement, eye involved in ~1/3 cases.

Question 20

How can herpes zoster impact the eye?

Answer 20

Dermatitis of the forehead (CN V1 territory) may involve the globe.

Question 21

Complications of herpes zoster affecting eye?

Answer 21

• Corneal keratitis, ulceration, perforation and scarring
• 2” iritis, 2” glaucoma, cataract
• Muscle palsies (due to CNS involvement); rare

Question 22

Treatment of herpes zoster affecting eye?

Answer 22

• Oral antiviral (e.g. acyclovir)
• Topical steroids as indicated for keratitis, iritis (supervised by ophthalmologist)
• Erythromycin ointment if conjunctival involvement.