4: Microbiology

Question 1

What is conjunctivitis?

Answer 1

Infectious inflammation of the conjunctiva

Question 2

What is keratitis?

Answer 2

Infectious inflammation of the cornea

Question 3

What is endophthalmitis?

Answer 3

Infectious inflammation of the entire eye

Question 4

What is chorioretinitis?

Answer 4

Inflammation of the choroid and retina (back of the eye)

Question 5

What is dacrocystitis?

Answer 5

Infectious inflammation of the lacrimal SAC

Question 6

Which microbes cause conjunctivits?

Answer 6

Bacteria

Viruses

Question 7

How can you tell the difference between bacterial and viral conjunctivitis?

Answer 7

Bacterial - loads of pus

Viral - watery

Question 8

What are the symptoms of conjunctivitis?

Answer 8

Red eye

Itchy, gritty, watery eye

Question 9

All neonates with conjunctivitis should be referred to who?

Answer 9

Ophthalmology

Question 10

Which bacteria can cause conjunctivitis?

Answer 10

Staph aureus

Strep pneumoniae

H. influenzae (especially in children)

Chlamydia trachomatis

Neisseria gonorrhoeae

Question 11

Which bacteria causes bacterial conjunctivitis especially in children?

Answer 11

H. influenzae

Question 12

Which STI can cause bacterial conjunctivits which is chronic, unresponsive to previous treatment and accompanied by urethritis or vaginitis?

Answer 12

Chlamydia trachomatis

Question 13

What must you do if you diagnose chlamydial conjunctivitis?

Answer 13

Alert people the patient has been in contact with

Question 14

What are some additional features of chlamydial conjunctivitis compared to normal bacterial conjunctivitis?

Answer 14

Follicles under eyelid - “rice grain pattern”

Subtarsal scarring if left untreated

Question 15

How is bacterial conjunctivitis investigated?

Answer 15

Swab

Question 16

How is bacterial conjunctivitis treated?

Answer 16

Topical antibiotics

Chloramphenicol drops (4x a day)

Oxytetracycline (for chlamydia)

Question 17

Which viruses can cause conjunctivitis?

Answer 17

Adenovirus

Herpes simplex virus

Herpes zoster virus

Question 18

What is the difference between bacterial and viral conjunctivitis?

Answer 18

Bacterial - pus

Viral - watery

Question 19

What may you see along conjunctivitis in someone with herpes simplex infection?

Answer 19

Cold sores

Question 20

Which virus reactivates in elderly people and can cause a painful rash in the dermatomes for CN V?

Answer 20

Herpes zoster virus

Question 21

What is the technical name for shingles affecting the forehead and eye area?

Answer 21

Ophthalmic zoster

Question 22

How is viral conjunctivitis investigated?

Answer 22

Swab

Question 23

How is ophthalmic zoster treated?

Answer 23

Oral antivirals

Aciclovir

(add on antibiotics if at risk of secondary infection)

Question 24

What can ophthalmic zoster cause if untreated?

Answer 24

Vision loss

Post-herpetic neuralgia

Question 25

Which microbes can cause a **keratitis**?

Answer 25

**Bacteria** **Viruses** **Fungi**

Question 26

What does a **bacterial keratitis** look like?

Answer 26

**Red eye** **Hypopyon**

Question 27

What is a **hypopyon**?

Answer 27

**Exudate in anterior chamber** at iridocorneal angle Seen in **bacterial keratitis**

Question 28

What name is given to a collection of pus in the anterior chamber as seen in bacterial keratitis?

Answer 28

**Hypopyon**

Question 29

Which Gram negative bacillus is a common cause of keratitis in people who wear contact lenses?

Answer 29

***Pseudomonas***

Question 30

How is **bacterial keratitis** treated?

Answer 30

**Topical antibiotics** HOURLY chloramphenicol drops ofloxacin

Question 31

How would you treat *Pseudomonas* conjunctivitis?

Answer 31

**Gentamicin**

Question 32

What is a pathognomic sign of **viral keratitis** due to herpes infection?

Answer 32

**Dendritic ulcer** White ulcer with loads of projections

Question 33

**Viral keratitis** is very ___ for the patient.

Answer 33

**painful**

Question 34

What is seen in the cornea in **viral keratitis** caused by **adenovirus**?

Answer 34

**Subepithelial infiltrates** Little white specks

Question 35

Adenovirus keratitis is usually **(unilateral / bilateral)**.

Answer 35

**bilateral**

Question 36

What are the classic features of a) herpes b) adenovirus keratitis?

Answer 36

**a) Dendritic ulcer** **b) Subepithelial infiltrates**

Question 37

How is **viral keratitis** treated?

Answer 37

**Topical antivirals** e.g aciclovir (add on topical antibiotics to prevent secondary infection)

Question 38

What should you suspect in a patient with **red eye** with a **hypopyon** and a history of farming / trauma from vegetation?

Answer 38

**Fungal keratitis​**

Question 39

What should you suspect in a patient with a **fever,** **painful eye movements and massive orbital swelling**?

Answer 39

**Orbital cellulitis**

Question 40

What is abnormal protrusion of the eye called?

Answer 40

**Proptosis**

Question 41

How is orbital cellulitis investigated?

Answer 41

**CT head** For abscesses

Question 42

How is orbital cellulitis treated?

Answer 42

**Broad spectrum antibiotics** ofloxacin, gentamin, cephalosporins...

Question 43

What is a **"devastating", painful** infection of the whole eye which is commonly caused by surgery?

Answer 43

**Endophthlamitis**

Question 44

**Endophthalmitis** is commonly caused by **commensal organisms**. What is an example? How do they get into the eye?

Answer 44

***Staph epidermidis*** During surgery

Question 45

How is endophthalmitis investigated?

Answer 45

**Aqueous / vitreous fluid sample** seeing as it affects the whole eye

Question 46

How is **endophthalmitis** treated?

Answer 46

**Intravitreal antibiotics** Injected directly into the eye - **amikacin, cephalosporins, vancomycin**

Question 47

What commonly causes **chorioretinitis** - infective inflammation of the retina?

Answer 47

**Parasites** **Cytomegalovirus** in AIDS patients

Question 48

What does the retina look like on fundoscopy of someone with **chorioretinitis**?

Answer 48

**Pizza**

Question 49

What can be seen in the retina of someone with **chorioretinitis**?

Answer 49

**Pizza** **Parasites** **Scar tissue**

Question 50

How is **parasite infection** of the eye investigated?

Answer 50

**Serology** (antibodies)

Question 51

What investigations would you do for a) orbital cellulitis b) conjunctivitis c) keratitis d) endophthalmitis e) parasitic chorioretinitis?

Answer 51

**a) CT head** **b) Swab** **c) Corneal scrapes** **d) Aqueous or vitreous fluid sample** **e) Serology**

Question 52

How would you treat a) uncomplicated bacterial conjunctivitis b) chlamydial conjunctivitis c) *Pseudomonas* conjunctivitis?

Answer 52

**a) Chloramphenicol drops** **b) Oxytetracycline drops** **c) Gentamicin drops**

Question 53

How would you treat a) viral conjunctivitis b) viral keratitis c) orbital cellulitis d) fungal keratitis e) endophthalmitis?

Answer 53

**a) Topical antivirals** (plus prophylactic antibiotics) **b) ""** **c) Broad spectrum antibiotics** (ofloxacin, gentamicin, cephs) **d) Topical antifungals** **e) Intravitreal antibiotics** (amikacin, cephs, vancomycin...)