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My Ophthalmology > Microbiology and Pharmacology > Flashcards

Microbiology and Pharmacology Flashcards

1
Q

What are the bacterial causes of conjunctivitis in neonates?

A
  • S.aureus, N.gonorrhoeae, C.trachomatis

- must be treated by ophthalmology

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2
Q

What are the bacterial causes of conjunctivitis in normal age groups?

A

S.aureus or S.pneumoniae with H.influenzae in children

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3
Q

How is bacterial conjunctivitis diagnosed and treated?

A
  • Swab
  • Give chloramphenicol drops (keep in fridge) or ointment (can’t see after administration)
  • Gentamicin for pseudomonas
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4
Q

What are the viral causes of conjunctivitis?

A

this isn’t as bad as bacterial as there is no sticky discharge

  • adenovirus
  • herpes simplex (skin rash)
  • herpes zoster (in a ganglion)
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5
Q

What is the treatment for viral conjunctivitis?

A

aciclovir (also stops post-herpetic neuralgia)

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6
Q

What are the features of chlamydial conjunctivitis?

A
  • chronic
  • unresponsive to treatments
  • low grade red eye with follicles (like grains of rice) on the conjunctiva
  • becomes scarred if it is not treated
  • use topical oxytetracycline
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7
Q

What are the features of bacterial keratitis in the cornea?

A
  • Pus in the eye called hypopyon
  • risk of scarring or the bacteria can cause perforation
  • hourly drops
  • usually due to scar or contact lenses but is rare
  • scrape for diagnosis
  • give quinolone eg ofloxacin or gentamicin and cefuroxime
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8
Q

What are the causes of viral keratitis in the cornea?

A

Herpes

  • Causes dendritic ulcer
  • Fluorescent dye to show where the epithelium is missing
  • painful and recurrent
  • Never give steroid eye drops as the virus can cause cornea to melt and perforation of cornea!!!!!

Adenovirus

  • Blurred vision for several months
  • Follows an URTI and is contagious
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9
Q

What are the features of fungal and other causes of keratitis?

A
  • Acanthamoeba is extremely painful and is due to contact lens, culture the contact lenses
  • Fungal is seen in farmers, is more defined, multiple organisms, treat with topical antifungals
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10
Q

What are the features of endophthalmitis of the eye globe?

A
  • post-surgical
  • loss of sight within 48 hours
  • very painful and the patient will be really unwell
  • S. epidermidis
  • treat with injected antibiotics into the vitreous under LA with a broad gauge needle
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11
Q

What are the features of cellulitis?

A
  • Orbital cellulitis pushes the eye forward by a bag of pus
  • Associated with ethmoid sinuses
  • unwell and pyrexial
  • erythema will be perfectly demarcated
  • children
  • can be preseptal or orbital
  • is staph, strep, coliforms, H. influenzae or anaerobes
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12
Q

What are the causes of chorioretinitis?

A
  • caused by AIDS
  • herpes in immunosuppressed patients
  • Toxoplasma is a protozoa infection which can be latent and reactivate
  • Toxocara canis is worm
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13
Q

What are the features of chloramphenicol?

A
  • Topical antibiotic
  • Stops bacterial protein being made
  • Bactericidal for strep and haemophilus
  • Bacteriostatic for staph
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14
Q

What main eye antibiotic classes inhibit cell wall synthesis?

A
  • Penicillins
  • Cephalosporins
    with their B lactam ring
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15
Q

What main eye antibiotic class inhibits nucleic acid synthesis?

A
  • Quinolones eg ofloxacin

inhibits DNA gyrase so nucleic acid synthesis so there is cell death

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16
Q

What are the main antiviral agents used?

A
  • acyclovir and ganciclovir

- inhibits viral DNA synthesis

17
Q

What is the benefit of chloramphenicol as a drug?

A

it is both lipophilic and hydrophilic so can penetrate all layers of the cornea

18
Q

What are hydrophobic and hydrophilic drugs limited by?

A
  • hydrophilic drugs are limited by the epithelium

- hydrophobic drugs are limited by the stroma

19
Q

How can topical steroids be altered to allow them to be better suited for their purpose?

A
  • add acetate = become hydrophobic

- add phosphate = become hydrophilic

20
Q

What is benzalkonium chloride used for?

A
  • kill bacteria
  • preservative
  • depletes the tear film = aids penetration of some drugs
21
Q

What are the features of prednisolone acetate?

A
  • hydrophobic
  • good for uninflamed cornea
  • used in post-op
22
Q

What are the features of prednisolone phosphate?

A
  • hydrophilic
  • not good for uninflamed cornea
  • used for cornea disease for low doses of steroids
23
Q

How can the systemic effect of drugs be stopped?

A

close off drainage system for 5 minutes then wipe excess tears to stop leaking down the throat

24
Q

What are steroids used for?

A
  • post op cataracts
  • uveitis
  • prevent corneal graft rejection
  • temporal arteritis
25
Q

What are the side-effects of steroids?

A
  • local = cataracts, glaucoma, exacerbation of viral infection
  • systemic = gastric ulceration, immunosuppression, osteoporosis, weight gain, diabetes and neuropsychiatric effects
26
Q

What are topical NSAIDs used for?

A

pain relief eg post refractive laser

27
Q

What are antihistamines used for?

A

hayfever or allergic conjunctivitis

28
Q

What are intra-vitreal injections used for?

A
  • give steroids intraocularly
  • effective concentration of drug at target but many drugs are toxic to the retina
    eg used in endophthalmitis and wet macular degeneration
29
Q

What are the features of local anaesthetic?

A
  • blocks sodium channels and impedes nerve damage

- used for examination, cataracts, foreign body removal and corneal scraping

30
Q

What can diagnostic dyes show in the eye?

A
  • corneal abrasions
  • dendritic ulcers
  • identify leak
  • tonometry
  • diagnosing nasolacrimal duct obstruction
  • angiography
31
Q

What do mydriatics do?

A

Eg tropicamide and phenylephrine

- causes pupil dilation by blocking parasympathetic supply to the iris

32
Q

What do parasympathomimetics do?

A

makes the pupil small to get the pressure down and open the drain

33
Q

What are the main side-effects of steroids, vigabatrin and ethambutol?

A
  • Steroids = cataracts
  • Vigabatrin = constricts the fields
  • Ethambutol = optic neuropathy
34
Q

What are the main side-effects of digoxin, choloquine and amiodarone?

A
  • Digoxin = affects ability to judge colour
  • Chloroquine = bulls eye maculopathy
  • Amiodarone = corneal deposits
35
Q

What should you never give to herpetic keratitis?

A

NEVER GIVE STEROIDS

My Ophthalmology (5 decks)

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