Microbiology Flashcards

1
Q

when is bacterial conjunctivitis a worry?

A

in neonates

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2
Q

causative organisms of neonate bacterial conjunctivitis

A

staph aureus
neisseria gonorrhoea
chlamydia trachomatis

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3
Q

causative organisms in other age groups outside neonates of bacterial conjunctivitis

A

staph aureus
strep pneumonia
H. influenza (especially children)

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4
Q

presentation of bacterial conjunctivitis

A

morning crust (yellow discharge)
difficulty opening eye
rapid onset
gritty eye (BUZZWORD)

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5
Q

diagnosis of bacterial conjunctivitis

A

swab

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6
Q

management of bacterial conjunctivitis

A

topical antibiotic e.g. chloramphenicol qds
fusidic acid for staph aureus
gentamicin for gram -ve

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7
Q

what does chloramphenicol treat?

A

most bacteria except pseudomonas aeruginosa

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8
Q

two ways of delivering chloramphenicol?

A

drops (need to be stored in the fridge)

ointment (difficult to see through)

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9
Q

when should you avoid chloramphenicol?

A

history of aplastic anaemia

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10
Q

action of chloramphenicol

A

inhibits peptidyl transferase enzymes (stops bacterial protein being made)

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11
Q

what is chloramphenicol bactericidal to?

A

strep

haemophilus

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12
Q

what is chloramphenicol bacteriostatic to?

A

staph

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13
Q

side effects of chloramphenicol

A

allergy
irreversible aplastic anaemia
grey baby syndrome (neonatal liver cannot cope)

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14
Q

what gram negatives is gentamicin used against in bacterial conjunctivitis?

A

coliforms

pseudomonas

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15
Q

what can neisseria gonorrhoeae additionally present with in bacterial conjunctivitis?

A

lid swelling
globe tenderness
conjunctival chemosis

this can lead to corneal ulceration and perforation (URGENT referral)

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16
Q

causes of viral conjunctivitis

A

adenovirus (pink eye)
herpes simplex
herpes zoster

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17
Q

presentation of viral conjunctivitis

A
sudden onset and rapidly progressive
can be bilateral due to contagious and spreading to other eye
watery
pain
pre-auricular nodes
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18
Q

what hygiene should be exercised in viral conjunctivitis?

A

strict hand hygiene
no sharing of towels

this is because it is highly contagious

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19
Q

diagnosis of viral conjunctivitis

A

swab

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20
Q

presentation of adenoviral conjunctivitis

A

red and inflamed eye
watery discharge (bacterial is stickier)
often history of URTI

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21
Q

management of adenoviral conjunctivitis

A

antibiotics only used if risk of secondary infection

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22
Q

presentation of herpes simplex conjunctivitis

A

vesicles on conjunctiva and eyelids

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23
Q

describe herpes zoster conjunctivitis

A

reactivation of V1, V2 and/or V3 (herpes zoster ophthalmicus)

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24
Q

management of herpes zoster conjunctivitis

A

acyclovir to minimise risk of post-hepatic neuralgia

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25
management of viral conjunctivitis
topical lubricant e.g. hypromellose (aim for preservative free as if the patient is using this 4-6 times a day then there is risk of irritation) acyclovir for herpes zoster
26
presentation of chlamydial conjunctivitis
``` chronic history low grade red eye follicles on inner eyelid (grains of rice) discharge pre-auricular lymphadenopathy ```
27
when to consider chlamydial conjunctivis
unresponsive to treatment | bilateral in young adults (contact tracing required)
28
management of chlamydial conjunctivitis
topical oxytetracycline as risk of subtarsal scarring (+ oral azithromycin if genital infection)
29
what to think in follicular conjunctivitis?
chlamydial conjunctivitis
30
presentation of allergic conjunctivitis
itch watery bilateral
31
management of allergic conjunctivitis
allergen avoidance topical antihistamines once stabilised use mast cell stabilisers e.g. sodium cromoglycate
32
define episcleritis
inflammation of the thin vascular sheet between the conjunctiva and sclera
33
who is episcleritis common in?
patients with collagen-vascular disease such as RA, sarcoidosis and IBD
34
management of episcleritis
NSAIDs | topical lubricants
35
define acute anterior uveitis (iridocyclitis)
inflammation of the iris and ciliary body
36
presentation of acute anterior uveitis (iridocyclitis)
sudden onset of pain (can radiate to brow and exacerbated by focusing on a near object) red eye and hyperaemia at limbus photophobia (BUZZWORD) smaller pupil, ptosis due to local tissue swelling blurred vision if significant inflammation then a hypopyon can form
37
what to do if it is a first presentation of acute anterior uveitis (iridocyclitis)
refer
38
what is acute anterior uveitis (iridocyclitis) linked to?
HLA-B27 (if multiple presentations do AI screen)
39
management of acute anterior uveitis (iridocyclitis)
mydriatics (cycloplegia e.g. cyclopentolate hydrochloride)= dilates pupil reducing risk of it getting stuck to the eye steroids e.g. dexamethasone to reduce inflammation
40
define blepharitis
inflammation of eyelids, usually a chronic condition affecting both eyes
41
presentation of blepharitis
redness around eyelid margins | patients complain of gritty eyes
42
why should bacterial keratitis be referred?
it eats the eyeball and can cause perforation
43
define keratitis
infection of the cornea
44
presentation of bacterial keratitis
loss of clear appearance | hypopyon
45
what is bacterial keratitis associated with?
other corneal pathology | wearing contacts lenses (swimming or sleeping)
46
diagnosis of bacterial keratitis
corneal scrap for microscopy
47
management of bacterial keratitis
hourly drops (including at night so may need to admit)
48
examples of drops used in bacterial keratitis
- 4-quinolone (oflaxacin)= gram -ve including coliforms, pseudomonas and H. influenza - gentamicin and cefuroxime= gram +ve and -ve
49
what can UVB exposure cause?
keratitis
50
causes of viral keratitis
herpes (HSV) | adenovirus
51
what does hepatic keratitis present with?
dendritic ulcer (branching)
52
diagnosis of hepatic keratitis?
fluorescence to show missing epithelium where virus is
53
presentation of hepatic keratitis
pain | recurrence can lead to reduced corneal sensation (vision)
54
management of hepatic keratitis
must use steroids with acyclovir/ ganciclovir as can cause corneal melt and perforation can use topical anaesthetic for examination but do not repeat as toxic
55
presentation of adenoviral keratitis
bilateral follows URTI contagious can affect vision
56
management of adenoviral keratitis
topical antibiotics only to prevent secondary infection | steroids to tame immune reaction
57
fungal keratitis causes
acanthamoeba (pseudomonas aeruginosa) | moraxella
58
what is fungal keratitis associated with?
wearing contacts younger patients chronic history those who work outside
59
presentation of fungal keratitis
extreme pain | more defined hypopyon
60
diagnosis of fungal keratitis
culture of contact lens and microscopy
61
management of fungal keratitis
urgent referral | topical anti-fungal e.g. natamycin
62
define orbital cellulitis
pus in the orbit
63
what can orbital cellulitis lead to?
can lead to compartment syndrome and proptosis
64
presentation of orbital cellulitis
pain, especially on eye movements as muscle are close to inflammation paranasal sinusitis (ethmoid) pyrexia history of URTI well demarcated erythema around the orbit
65
diagnosis of orbital cellulitis
CT to show orbital abscesses
66
secondary causes of orbital cellulitis
``` infected chalazion (cyst on eyelid due to blocked duct) dacryocystitis ```
67
two types of orbital cellulitis
pre-septal (compresses optic nerve) | orbital (does not compress optic nerve)
68
causative organisms in orbital cellulitis
large spectrum of microorganisms so manage with broad spectrum antibiotics
69
management of orbital cellulitis
broad spectrum antibiotics | abscess may require drainage
70
define endophthalmitis
infection of the inside of the eye
71
cause of endophthalmitis
almost always post surgery (return 2-3 days after with pain) | endogenous (septicaemia)
72
presentation of endophthalmitis
pain decreasing vision (lost in 48 hours and irreversible) very red eye
73
causative organisms of endophthalmitis
commensals e.g. staph epidermidis
74
diagnosis of endophthalmitis
aqueous/vitreous for culture
75
management of endophthalmitis
antibiotic injections into vitreous under LA (amikain/ceftazidime/ vancomycin) topical antibiotics systemic antibiotics
76
define chorioretinitis
inflammation of the choroid and retina
77
cause of chorioretinitis in AIDS
CMV
78
cause of chorioretinitis in immunosuppressed
HSV (or when run down/tired)
79
two parasitic causes of chorioretinitis
``` toxoplasmosis toxocara canis (worms) ```
80
where does toxoplasmosis come from?
cats raw meat mother to foetus (IgG)
81
presentation of toxoplasmosis
flu-like illness cyst forming macula scarred reactivation in later life can affect vision
82
what do you get toxocara canis from?
cats | dogs
83
describe toxocara canis
unable to replicate so remains as larvae | reactivate and produce granulomas
84
diagnosis of parasitic choriretinitis
serology
85
define dacrocystitis
stagnation of the drainage of the lacrimal duct
86
what does dacrocystitis lead to?
occlusion of the sac causing swelling due to excess fluid and a secondary infection
87
management of dacrocystitis
penicillin