Week 1 - G - Microbiology of eye infections

Question 1

Give an example of a gram negative cocci?

Answer 1

Neisseria meningitidis or gonorrhoeae

Question 2

What is inflammation of the conjunctivae known as? What is inflammation of the cornea known as?

Answer 2

Conjunctivae - conjunctivitis

Cornea - keratitis

Question 3

What is inflammation of the aqueous and vitreous humour known as?

Answer 3

Endopthalmitis

Question 4

Bacterial conjunctivits presents with redness of the eye and pus usually What are bacterial causes of conjunctivitis in neonates? (remmeber can get STDs in neonates through mother to infant trasmisission)

Answer 4

Staph aureus

Neisseria gonorrhoeae

Chlamydia trachomatis

Question 5

In all other ages, bacterial conjunctivits is usually caused by staph aureus or strep pneumonia or ? The third cause is especially common in chidlren

Answer 5

Haemophilus influenza

Question 6

Child wakes up with eye glued shut The eye is red and itchy and there is a pus like substance leaking What is this?

Answer 6

Bacterial conjunctivits

Question 7

What is the treatment of bacterial conjunctivits? (not including chlamydia trochamtis)

Answer 7

Bathe / clean the eyelids regularly to remove crusting

Second line - Treat with swab and then chloramphenical eye drops usually 4 times daily

Question 8

Where should chloramphenical be stored after use? Chloramphenicol should be avoided in patients with allergy What should be suspected if patient complains of worsening symtpoms?

Answer 8

Should be stored in fridge

Worsening symptoms with worsening itchiness may be due to a chloramphenical allergy

Question 9

What gram negative bacilli does chloramphenical not cover?

Answer 9

Does not cover pseudomonas arguinosa

Question 10

Viral conjunctivitis usually follows a history of URTI – usually presents with bilateral eye watering What is the most common viral cause of viral conjunctivits?

Answer 10

Viral adenovirus - usually starts in one eye and then spreads but lasts around 2 weeks

Question 11

What are the symptoms of a viral conjunctivirs?

Answer 11

Presents with a watery discharge and swelling of the conjunctivae

Question 12

What is another viral cause of viral conjunctivits and can present with a sign on the tip of the nose? What is this sign known as?

Answer 12

Herpes zoster

Sign on tip of nose is the Hutchison sign which means the eye has been affected as the tip of the nose is supplied by the nasociliary nerve which is a branch of the opthalmic nerve

Question 13

In a patient with herpes zoster - Herpes zoster is infection that results when varicella-zoster virus reactivates from its latent state in a posterior dorsal root ganglion. What should you start the patient on?

Answer 13

Start the patient on oral acyclovir

Question 14

What can occur long after the shingles disappeared causing a burning pain ?

Answer 14

Post-herpetic neuralgia - there is no cure

Question 15

What is suspect in bilateral conjunctivitis in young adults ?

Answer 15

CHlamydia trachomatis causing chlamydial conjunctivitis

Question 16

In adults with chlamydial conjunctivits, where else can they complain of having a pain?

Answer 16

Burning sensation, stinging pain while urinating (observed in both men & women); watery discharge from vagina

Question 17

What is keratitis?

Answer 17

Inflammation of the cornea of the eye

Question 18

What is the small transparent canal running through the vitreous gel from the optic nerve to the lens? If infection in the cornea spreads in this it can infect the whole eye

Answer 18

Hyaloid canal - Cloquets canal

Question 19

Bacterial keratitis can cause the accumulation of inflammatory mediators in the anterior chamber of the eye, appears as a white exudate What is this known as?

Answer 19

Hypopyon

Question 20

People who wear contact lenses are more likely to get keratitis What bacteria is common in people who wear contact lens as they live in the solution the contact lens is stored in?

Answer 20

Pseudomonas aerguinosa

Question 21

What is the treatment of the psuedomonas aerguinosa bacteria causing keratitis?

Answer 21

Fluoroquinolone - eg oflaxacin, levoflaxacin

Question 22

When giving eye drops for bacterial keratitis, an eye scraping is taken and eye drops are then given Which eye drops are given t cover most organism before the scraping culture comes back?

Answer 22

Give flouroqinolone (eg oflaxacin) every one hour for 48 hours

Question 23

What is a dendritic ulcer the most common sign off? Dendritic meaning branch

Answer 23

Most common sign of herpetic keratitis - herpetic keratitis is due to HSV

Question 24

Herpetic keratitis is Very painful Can be recurrent recurrences eventually result in reduced corneal sensation What is it treated with? and what should be avoided in treatment?

Answer 24

Treated with topical acyclovir

Avoid treatment with steroids as can cause a corneal melt which can lead to perforation and more infection

Question 25

Orbital cellulitis can have pain on eye movements What does the orbital septum lie in front? What is orbital cellulitis often associated with?

Answer 25

Orbital septum lies in front of the tarsal plates of the eye Is associated with paranasal sinusitis

Question 26

What colour is the eyelid in orbital cellulits? What can happen if left untreated? What is the common bacterial cause of orbital cellulitis in children?

Answer 26

Eyelid is left red/purple Can cause blindness, compartment syndrome due to swelling Common cause in children is H.influenza

Question 27

Orbital cellulitis as said is usually due to Hinfluenza, what other organsims can cause it?

Answer 27

Can be caused by staph aureus and strep pneumoniae

Question 28

What is a coliform? Give an example?

Answer 28

Gram negative bacilli Example is Ecoli or klebsiella pneumoniae

Question 29

Devastating infection inside of the eye Very very painful with decreasing sight Usually due to surgery of the eye eg cataracts What is this known as?

Answer 29

Endopthalmitiis - treat with injection antibiotics into the eye

Question 30

What commensal is the most common cause of endopthalmitis?

Answer 30

Staph epidermis

Question 31

What is the treatment of antibiotics for endopthalmitis?

Answer 31

Intravitreal Vancomycin + Amikacin or Intraviteral Vancomycin + Ceftazidime

Question 32

What type of antibiotic is amikacin? What type of antibiotic is ceftazidime?

Answer 32

It is an aminoglycoside It is a cephalosporin

Question 33

Chorioretinitis is an inflammation of the choroid (thin pigmented vascular coat of the eye) and retina of the eye. Can be caused in AIDS due to cytomegalovrius What is the treatment of CMV?

Answer 33

Ganciclovir

Question 34

How are eye infections dianosed? (eg bacterial, viral, chlamydial and corneal)

Answer 34

Use swabs for all eye infections apart from keratitis in which you use corneal scrapings

Question 35

What eye infection can acanthomoeba cause? What should you tell the patient to bring with if this is the case of the scraping?

Answer 35

Seen in fungal causing keratitis Tell patient to bring their contact lenses with them

Question 36

Chloramphenical is the most commonly used topical antibiotic for eye infection (ointment or drops) as it treats most bacteria except Pseudomonas aeruginosa For which bacteria is it bacteriostatic or bacteriocidal Staph aureus? H.Influenza? Strep?

Answer 36

Strep and Hinfluenza - is bacteriocidal Staph aureus is bacteriostatic

Question 37

What are the three main side effects of chloramphenicol? One is in babies

Answer 37

Can cause allergy Aplastic anaemia And grey baby syndrome

Question 38

Aplastic anemia is a rare disease in which the bone marrow and the hematopoietic stem cells that reside there are damaged. This causes a deficiency of all three blood cell types (pancytopenia) What are the three blood cell losses then?

Answer 38

Red blood cell - anaemia White blood cell - leukopaenia Platelets - thrombocytopaenia

Question 39

Gray baby syndrome (also termed Gray or Grey syndrome) is a rare but serious side effect that occurs in newborn infants (especially premature babies) following the accumulation of antibiotic chloramphenicol.

Answer 39

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Question 40

What is used for dendritic ulcer treatment? What is the different in strength between this treatment and the one for skin?

Answer 40

Acyclovir is used 3% strength for eye 5% strength for skin

Question 41

Due to chloramphenicol bein bacteriostatic in staph aureus, what is used to treat this if staph aureus causes bacterial conjunctivits?

Answer 41

Fusidic acid is given

Question 42

What treatmen can be given to cover most gram negative organsism incuding coliforms?

Answer 42

Gentamicin

Question 43

What drug is given to treat Chlamydial conjunctivitis? What may adults also need in conjucntion with this for genital chlamydial infection?

Answer 43

Give topical oxytetracylcine for Chlamydial conjunctivitis Give oral doxycycline in adults for the genital chlamydial infection

Question 44

A fluoroquinolone will cover most gram negative bacteria including pseudomonas and is used in treating bacterial keratitis What is the alternative treatment option used to treat bacterial keratitis and covers most gram positive and negative bacteria?

Answer 44

Gentamicin + cefuroxime