Microbiology Flashcards

1
Q

What bacteria can cause conjunctivitis in neonates?

A

Staphylococcus aureus
Neisseria gonorrhoea
Chlamydia trachomatis

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2
Q

What bacteria commonly cause conjunctivitis in all bar neonates?

A

Staphylococcus aureus
Streptococcus pneumoniae
Haemophilus influenzae (esp in children)

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3
Q

What is conjunctivitis?

A

Inflammation of the conjunctiva

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4
Q

What are the common symptoms of bacterial conjunctivitis?

A
Minimal pain
Sticky eye
Purulent discharge
Red eye
Spreads between eyes
Clear cornea
Normal pupillary response
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5
Q

How is conjunctivitis diagnosed?

A

Swab

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6
Q

How is conjunctivitis treated?

A
Chloramphenicol 
If neonate - ophthalmology 
Fusidic acid if staphyloccous aureus
Pseudomonas - gentamicin
Chlamydia - oxytetracycline and azithromycin
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7
Q

What are the side effects of chloramphenicol?

A

Aplastic anaemia

Grey baby syndrome

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8
Q

What viruses commonly cause viral conjunctivitis?

A

Adenovirus
Herpes simplex
Herpes zoster

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9
Q

What are the symptoms of viral conjunctivitis?

A
Swollen and tender preauricular lymph nodes
Watery eye
Red eye
Extreme eye movements can be painful
Tends to occur with URTI
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10
Q

How will herpes simplex conjunctivitis present?

A

Vesicles around eyes that spreads to eye

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11
Q

What must be done in a patient with chlamydial conjunctivitis?

A

Contact tracing

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12
Q

How will chlamydial conjunctivitis present?

A

Follicular changes in eyelid

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13
Q

What can untreated chlamydial conjunctivitis cause?

A

Subtarsal scarring

Damage to cornea or dry eye

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14
Q

What is the classical sign of bacterial keratitis?

A
Hypopyon
Pain 
Photophobia
Reduced visual acuity
Epiphora
Red eye
Opacity
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15
Q

How is bacterial keratitis (corneal ulcer) treated?

A

Hourly drops for 48hrs in hospital

Daily review

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16
Q

How can a bacterial keratitis occur?

A

In association with other corneal pathology or contact lens wear

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17
Q

What bacteria can cause bacterial keratitis?

A

Staphylococcus aureus
Streptococcus
Pseudomonas

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18
Q

What viruses can cause keratitis?

A

Herpes simplex

Adenovirus

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19
Q

How can viral keratitis occu?

A

In a normal cornea

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20
Q

What is the characteristic sign of herpetic keratitis?

A

Dendritic ulcer

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21
Q

What are the symptoms of herpetic keratitis?

A

Very painful
Can be recurrent
Recurrences eventually result in reduced corneal sensation

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22
Q

Why should herpetic keratitis NOT be treated with steroids?

A

Corneal melt and perforation of the cornea

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23
Q

Where does herpes simplex reside?

A

In the trigeminal nerve - will reactivate

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24
Q

What is the characteristic sign of adenoviral keratitis?

A

Subepithelial infiltrates

Reduced vision

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25
Q

How is adenoviral keratitis treated?

A

Topical antibiotic to prevent secondary infection
Artificial tears
Steroids to speed up recovery if chronic and you are SURE it is not herpetic

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26
Q

What keratitis is associated with contact lens wearing?

A

Acanthamoeba

Pseudomonas aeruginosa

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27
Q

What is the disease progression of fungal keratitis?

A

More indolent that microbial
Usually a history of trauma from vegetation
Takes a long time to heal

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28
Q

What are the symptoms of orbital cellulitis?

A
Painful on eye movements
Proptosis
Paranasal sinusitis
Pyrexial
Sight threatening
Cared for by ENT and ophthalmology
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29
Q

What investigation is required in suspicion of orbital cellulitis?

A

CT scan
Compartment syndrome
Can compromise the optic nerve

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30
Q

How does orbital cellulitis occur?

A

Direct extension from sinus
Extension from focal orbital infection (infected chalazion, dacryocystitis)
Post-op

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31
Q

What organisms commonly cause orbital cellulitis?

A
Staphylococci
Streptococci
Coliforms
Haemophilus influenzae
Anaerobes
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32
Q

How is orbital cellulitis treated?

A

Broad spectrum antibiotics and monitor closely

Abscess will require drainage

33
Q

What is endophthalmitis?

A
Devastating infection inside of eye
Post-surgical or endogenous 
Painful +++ with decreasing vision 
V red eye
Sight threatening
34
Q

What bacteria can cause endophthalmitis?

A

Conjunctival commensals

Staphylococcus epidermis

35
Q

How is endophthalmitis treated?

A

Intravitreal amikacin/ cefazidime/ vancomycin
Topical antibiotics
Systemic antibiotics

36
Q

What is chorioretinitis?

A

Infection of the choroid of retina

37
Q

What can cause chorioretinitis?

A

Cytomegalovirus
Toxoplasma gondii
Toxocara canis

38
Q

What will CMV retinitis look like under fundoscopy?

A

Huge areas of exudation and haemorrhage

39
Q

How is CMV retinitis treated?

A

Injections in eye

40
Q

How is keratitis diagnosed?

A

Fluorescein

Corneal scrape

41
Q

What is endophthalmitis?

A

Inflammation of the intraocular space occupied by vitreous humor

42
Q

What is blepharitis?`

A

Inflammation of the eyelids

43
Q

What can cause anterior blepharitis?

A

Seborrhoeic dermatitis

Staph aureus

44
Q

What can cause posterior blepharitis?

A

Acne rosacea

Meibomian gland dysfunction

45
Q

What are the symptoms of blepharitis?

A
Itchy, sore, red eyelid
Burning sensation in eyes
Photophobia
Swollen eyelid margins
Cysts
46
Q

What is dacryocystitis?

A

Blockage of lacrimal system

47
Q

How is dacryocystitis treated?

A

Broad spectrum antibiotics

48
Q

What is a chalazion?

A

Meiboman cyst treated with heat and daily massage

49
Q

What causes toxoplasmosis in the eye?

A

Protozoan infection with toxoplasmosis ondii

50
Q

Where can toxoplasmosis gondii be found?

A

Cats and raw meat

51
Q

What is the disease progression of toxoplasmosis?

A

Mild flu like illness
Scar forming
Can reactivate

52
Q

What causes toxocara and where is it found?

A

Parasitic nematode
Affects cats and dogs
Unable to replicate in humans

53
Q

How does toxocara affect the eye?

A

Forms granulomas which can cause irreversible visual loss`

54
Q

How are toxoplasma and toxocara diagnosed?

A

Serology

55
Q

How is acanthamoeba diagnosed?

A

Microscopy/ culture

56
Q

How is endophthalmitis diagnosed?

A

Aqueous/ vitreous humour culture

57
Q

What is the mode of action of chloramphenicol?

A

Inhibits peptidyl transferase enzyme to stop bacterial protein
Bactericidal for strep and haemophilus
Bacteriostatic for staph

58
Q

How do quinolones work?

A

Inhibits DNA gyrase, an enzyme that compresses bacterial DNA into supercoils
Inhibition of DNA gyrase leads to unwinding of supercoils and cell death

59
Q

What bacteria can contaminate antibiotic bottles?

A

Pseudomonas - can cause bad corneal ulcers

60
Q

What antiviral is used for dendritic ulcers?

A

Acyclovir which inhibits viral DNA synthesis

61
Q

How is bacterial keratitis treated?

A

Ofloxacin (treats coliform, pseudomonas, haemophilus)

Gent and cefuroxime (treats most gram positive and gram negative organisms)

62
Q

What should be taken in the history of a red eye?

A
Pain - grittiness, ache
Itch
Discharge
Photophobia
Visual loss
Past ocular disorders
Contact lenses
63
Q

What can cause anterior blepharitis?

A

Seborrhoeic

Staphylococcal aureus

64
Q

What can cause posterior blepharitis?

A

Meibomian gland dysfunction

65
Q

What are the symptoms of seborrhoeic blepharitis?

A

Lid margin red
Scales
Dandruff
No ulceration, lashes unaffected

66
Q

What are the symptoms of staphylococcal blepharitis?

A
Lid margin red
Lashes distorted, loss of lashes, ingrowing lashes (trichiasis) 
Styes
Corneal staining
Marginal ulcers
67
Q

What is a meibomian cyst called?

A

Chalazia

68
Q

What is posterior blepharitis associated with?

A

Acne rosacea

69
Q

How is blepharitis treated?

A

Lid hygiene
Supplementary tear drops
Oral doxycycline for 2-3 months

70
Q

What can cause chronic conjunctivitis?

A
Blepharitis
Chlamydial infection
Keratoconjunctiviti sicca
Lacrimal disease (chronic dacryocystitis) 
Glaucoma medication
Sub-tarsal foregin body
71
Q

What can cause peripheral corneal ulcers?

A

RA
Hypersensitivity
Granulomatosis with polyangitis
Polyarteritis

72
Q

What are signs of anterior uveitis?

A
Cirilary injection 
Cells and flares in anterior chamber
Keratic precipitates
Hypopyon
Synechiae
73
Q

What are the symptoms of anterior uveitis?

A

Red eye
Dull ache
Photophobia
Referred pain to eyebrow

74
Q

How is anterior uveitis managed?

A

Topical steroids
Mydriatics
Investigate for systemic association

75
Q

What is associated with episcleritis?

A

Gout

76
Q

What is associated with scleritis?

A

RA

Wegner’s

77
Q

What are the signs and symptoms of scleritis?

A

Painful
Injection of deep vascular plexus
Phenylephrine test will show no blanching

78
Q

How is scleritis treated?

A

Oral NSAIDs
Oral steroids
Steroid sparing agents