Microbiology Flashcards

1
Q

what are the types of herpes simplex virus

A

types 1 and 2
type 1 is acquired children
HSV2 more reactivations

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2
Q

what does HSV1 cause

A

oral lesions, primary gingivostomatitis

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3
Q

how does HSV infection spread

A

through saliva contact

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4
Q

what are the features of primary gingivostomatitis

A
disease of pre school children 
primary infection
systemic upset 
lips, buccal mucosa, hard palate 
vesicles, ulcers 
fever 
local lymphadenopathy
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5
Q

do all people with HSV1 infection get primary gingivostomatitis

A

no, only severe end of the spectrum

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6
Q

what is the treatment for primary gingivostomatitis

A

aciclovir treatment

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7
Q

how long can primary gingivostomatitis take to recover

A

up to three weeks

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8
Q

describe HSV latency

A

after primary infection virus becomes inaction in local ganglion (sensory nerve cells) usually trigeminal nerve
can reactivate and infect mucosal surfaces

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9
Q

what is a cold sore

A

reactivation of HSV1 from nerves causes active infection

various stimuli

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10
Q

what is the treatment for coldsores

A

aciclovir therapy or suppression (aciclovir doesn’t prevent latency)

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11
Q

do all people with HSV1 get clinical recurrences of cold sores

A

no (about half do)

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12
Q

what type of HSV causes oral herpetic lesions

A

HSV1

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13
Q

does HSV usually cause recurrent intra-oral lesions

A

not usually

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14
Q

what is herpetic wiplow

A

painful infection of the finger by HSV- an occupational hazard of dentistry and anaesthetics

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15
Q

how is HSV diagnosed

A

swab of lesion (burst vesicle better for picking up live viruses)
PCR

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16
Q

what causes herpangina

A

coxsackie viruses (enterovirus)

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17
Q

what are the features of herpangina

A

vesicles/ ulcers on soft palate

pre school children

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18
Q

how you diagnose herpangina

A

PCR

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19
Q

what causes hand, foot and mouth disease

A

coxasckie viruses (enteroviruses)

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20
Q

what are the features of hand food and mouth disease

A

family outbreaks common
gingival stomatitis around mouth
blisters on hands and mouth

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21
Q

how do you diagnose hand foot and mouth disease

A

PCR

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22
Q

what is a chancre

A

painless indurated ulcer that you get in primary syphllis at the site of entry of bacterium treponema pallidum

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23
Q

where do you get chancre is syphillis

A

genital, oral

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24
Q

what happens if primary syphillis is untreated

A

progresses to secondary and tertiary syphillis

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25
Q

is syphillis painful

A

no

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26
Q

what is the treatment for syphillis

A

penicillin

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27
Q

does syphillis have latency

A

no

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28
Q

what are apthous ulcers

A

non viral
self limiting
recurring painful ulcers of the mouth that are round or ovoid and have inflammatory halos

confined to mouth, absence of systemic disease

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29
Q

how long to apthous ulcers last

A

begin in childhood, usually go away by 3rd decade

each ulcer lasts less than 3 weeks

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30
Q

what systemic diseases can you get recurrent ulcers in (non viral)

A
behects disease 
gluten sensitive enteropathy/ IBD
reiters disease 
drug reactions 
skin diseases
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31
Q

what are the peaks in ages in acute throat infections

A

children aged 5-10 years

then 15-25 years

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32
Q

what is acute pharyngitis

A

inflammation of the part of the throat behind the soft palate (oropharynx)

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33
Q

what causes throat infection

A

viral (most common) or bacterial

common cold, influenza, streptococcal

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34
Q

what should you suspect in a patient aged 15-25 if sore throat persists into the second week

A

mononucleosis (glandular fever)

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35
Q

what causes mononucleosis

A

ebstein barr virus

36
Q

what are the rare causes of throat infection

A

HIV, gonococcal pharyngitis, diptheria

37
Q

what are the non infectious causes of a sore throat

A
physical irritation
-GORD
-chronic irritation from cigarette smoke
-alcohol
-hay fever 
cancer look for red flags
38
Q

when is a sore throat a medical emergency

A

when there is stridor or respiratory difficulty (dont examine throat)

39
Q

what is the usual course of a sore throat

A

will resolve in 3 days (40%)- a week (85%)

40
Q

what are the complications (rare) of a throat infection

A

otitis media (most common)
peri-tonsillar abscess (quinsy)
para-pharyngeal abscess
mastoiditis

41
Q

what is the management for a sore throat

A

self care (analgesia- paracetamol/ ibruprofen, medicated lozenges, avoid hot drinks, drink lots)
prescribing antibiotics only where appropriate
identify and manage immunosuppressed people

42
Q

what patients with a sore throat need admission/ referral

A

is suspected throat cancer (persistent sore throat, esp if neck mass)
sore or painful throat that lasts 3/4 weeks, pain on swallowing or dysphagia for more than 3 weeks
red/white patches or ulceration or swelling of the oral/pharyngeal mucosa persists for more than 3 weeks
stridor/ resp difficulty is an emergency

43
Q

what causes the vast majority of sore throats

A

viruses- dont give antibiotics

44
Q

what is the most common cause of a bacterial sore throat

A

strep pyogenes (group A or group B haemolytic strep)

45
Q

what are the clinical features of strep pyogenes throat infection

A

acute follicular tonsillitis

46
Q

what is the treatment for strep pyogenes throat infection

A

penicillin

47
Q

describe the features of strep pyogenes

A

gram positive cocci chains

beta haemolysis

48
Q

what are the complications of strep pyogenes infection

A
rheumatic fever (3 weeks post sore throat, fever, arthritis, pancarditis) 
glomerulonephritis (1-3 weeks post sore throat, haematuria, albuminuria, oedema)
49
Q

what are the scoring criteria for group A beta haemolytic strep infections that show whether you need to give antibiotics by showing the risk of the infection

A

centor and fever PAIN criteria

50
Q

what should you do if someone is immunosuppressed an gets a throat infection

A

do FBC, referral, consider antibiotics

51
Q

what can cause neutropenia

A
carbimazole
chemo 
asplenia 
leuaemia
aplastic anaemia 
HIV
52
Q

when in throat infections should you consider giving phenoxymethylpenicillin for a throat infection

A

if fever pain score of 4/5

centor score of 3/4

53
Q

what are the clinical signs of diptheria

A

severe sore throat with a grey white membrane across the pharynx (pseudomembrane)

54
Q

what cause the majority of the disease in diptheria

A

the exotoxin produced by the bacteria is cardiotoxic and neurotoxic

55
Q

what prevents diptheria

A

vaccine- toxoid vaccine

56
Q

what is the treatment for diptheria

A

antitoxin (most important) and supportive (maintain the airway)
pencillin/ erythtomycin

57
Q

what are the features of infective mononucleosis

A
fever
enlarged lymph nodes 
sore throat 
pharyngitis 
tonsilitis 
malaise 
lethargy 

can get post viral syndrome with fatigue lasting for up to 6 months

also can get jaundice/ hepatitis, rash, haematology, splenomegaly, palatal petechiae

58
Q

what will there be presence of in mononucleosis on blood films

A

atypical lymphocytes

59
Q

what are the complications of mononucleosis

A
anaemia 
thrombocytopenia 
splenic rupture (avoid contact sports)
upper airway obstruction 
risk of lymphoma
60
Q

what is the treatment for mononucleosis

A
self limiting 
best rest 
paracetamol 
avoid sport 
antivirals not effective 
corticosteroids may have a role in some complicated cases
61
Q

should you give steroids to help viruses

A

NO

62
Q

how do you confirm mono

A

epstein barr virus IgM
heterophile antibody
blood count and film
liver function tests

63
Q

what infections present similarly to mono

A

cytomegalovirus
toxoplasmosis
primary HIV infection

64
Q

what are the clinical signs of candida/thrush

A

white patches on red, raw mucous membranes in throat/ mouth

65
Q

what causes candida

A

candida albicans

endogenous (post anitbiotics, immunosuppressed, smokers, inhaled steroids)

66
Q

what is the treatment for candida

A

nystatin or fluconazole

67
Q

when should you investigate candida

A

if recurrent (suggests somethings wrong with T cells)

68
Q

what is acute otitis media

A

an upper resp infection involving the middle ear by extension of infection up the eustachian tube

69
Q

how does acute otitis media present

A

with ear ache

70
Q

what are common infections of the middle ear

A

often viral with bacterial secondary infection

most common bacterial= haemophilus influenzae, strep pneumoniae, strep pyogenes

71
Q

can you get samples for diagnosis in otitis media

A

only if eardrum has been perforated

72
Q

what is the treatment for infections of the middle ear

A

80% resolve without antibiotics
1st- amoxicillin
2nd-erthryomycin

73
Q

what is malignant otitis externa

A

an extension of otitis externa into the bone surrounding the ear canal (i.e. the mastoid and temporal bones). Malignant otitis, without treatment, is a fatal condition. Osteomyelitis will progressively involve the skull and meninges

74
Q

what are the symptoms and signs of malignant otitis

A

pain, headache, more severe than signs suggest

granulation tissue at the bone- cartilage junction of the ear canal= exposed bone in ear canal
facial nerve palsy

75
Q

what are the risk factors for malignany otitis

A

diabetes, radiotherapy to head and neck

76
Q

what investigations to diagnose malignant otitis

A

PV, CRP, imaging, biopsy

77
Q

IMPORTANT what are the side effects of quinolones

A

tendonitis
Appetite decreased; arthralgia; asthenia; constipation; diarrhoea; dizziness; dyspnoea; eye discomfort; eye disorders; fever; gastrointestinal discomfort; headache; hearing impairment; hepatic disorders; myalgia; nausea; QT interval prolongation; rhabdomyolysis; skin reactions; sleep disorders; taste altered; vision disorders; vomiting

78
Q

how do you treat malignant otitis

A

gentamicin 3x a day IV

79
Q

what is otitis externa

A

inflammation of the outer ear canal

80
Q

what are the clinical signs of otitis externa

A

redness, swelling of ear canal
itchy
sore
discharge/ increased amounts of ear wax- affects hearing

81
Q

what commonly causes otitis externa

A

staph aureus
proteus spp
pseudomonas aeruginosa

associated with swimmers

fungal causes:
aspergillus niger
candida albicans

82
Q

what is the management for otitis externa

A

topical aural toilet
swab in unresponsive/ severe cases
treatment depends on culture

83
Q

what are the features acute sinusitis

A

mild discomfort over frontal/ maxillary sinuses due to congestion

seen in patients with URTI (viral)

84
Q

what indicates a secondary bacterial infection in acute sinusitis

A

severe pain and tenderness with purulent nasal discharge

85
Q

what is the treatment for acute sinusitis

A

usually lasts 2.5 weeks
antibiotics only for severe/ deteriorating cases
1st line phenomethylpenicillin
2nd line doxycycline (not in children)