Microbiology Flashcards
what are the types of herpes simplex virus
types 1 and 2
type 1 is acquired children
HSV2 more reactivations
what does HSV1 cause
oral lesions, primary gingivostomatitis
how does HSV infection spread
through saliva contact
what are the features of primary gingivostomatitis
disease of pre school children primary infection systemic upset lips, buccal mucosa, hard palate vesicles, ulcers fever local lymphadenopathy
do all people with HSV1 infection get primary gingivostomatitis
no, only severe end of the spectrum
what is the treatment for primary gingivostomatitis
aciclovir treatment
how long can primary gingivostomatitis take to recover
up to three weeks
describe HSV latency
after primary infection virus becomes inaction in local ganglion (sensory nerve cells) usually trigeminal nerve
can reactivate and infect mucosal surfaces
what is a cold sore
reactivation of HSV1 from nerves causes active infection
various stimuli
what is the treatment for coldsores
aciclovir therapy or suppression (aciclovir doesn’t prevent latency)
do all people with HSV1 get clinical recurrences of cold sores
no (about half do)
what type of HSV causes oral herpetic lesions
HSV1
does HSV usually cause recurrent intra-oral lesions
not usually
what is herpetic wiplow
painful infection of the finger by HSV- an occupational hazard of dentistry and anaesthetics
how is HSV diagnosed
swab of lesion (burst vesicle better for picking up live viruses)
PCR
what causes herpangina
coxsackie viruses (enterovirus)
what are the features of herpangina
vesicles/ ulcers on soft palate
pre school children
how you diagnose herpangina
PCR
what causes hand, foot and mouth disease
coxasckie viruses (enteroviruses)
what are the features of hand food and mouth disease
family outbreaks common
gingival stomatitis around mouth
blisters on hands and mouth
how do you diagnose hand foot and mouth disease
PCR
what is a chancre
painless indurated ulcer that you get in primary syphllis at the site of entry of bacterium treponema pallidum
where do you get chancre is syphillis
genital, oral
what happens if primary syphillis is untreated
progresses to secondary and tertiary syphillis
is syphillis painful
no
what is the treatment for syphillis
penicillin
does syphillis have latency
no
what are apthous ulcers
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
how long to apthous ulcers last
begin in childhood, usually go away by 3rd decade
each ulcer lasts less than 3 weeks
what systemic diseases can you get recurrent ulcers in (non viral)
behects disease gluten sensitive enteropathy/ IBD reiters disease drug reactions skin diseases
what are the peaks in ages in acute throat infections
children aged 5-10 years
then 15-25 years
what is acute pharyngitis
inflammation of the part of the throat behind the soft palate (oropharynx)
what causes throat infection
viral (most common) or bacterial
common cold, influenza, streptococcal
what should you suspect in a patient aged 15-25 if sore throat persists into the second week
mononucleosis (glandular fever)
what causes mononucleosis
ebstein barr virus
what are the rare causes of throat infection
HIV, gonococcal pharyngitis, diptheria
what are the non infectious causes of a sore throat
physical irritation -GORD -chronic irritation from cigarette smoke -alcohol -hay fever cancer look for red flags
when is a sore throat a medical emergency
when there is stridor or respiratory difficulty (dont examine throat)
what is the usual course of a sore throat
will resolve in 3 days (40%)- a week (85%)
what are the complications (rare) of a throat infection
otitis media (most common)
peri-tonsillar abscess (quinsy)
para-pharyngeal abscess
mastoiditis
what is the management for a sore throat
self care (analgesia- paracetamol/ ibruprofen, medicated lozenges, avoid hot drinks, drink lots)
prescribing antibiotics only where appropriate
identify and manage immunosuppressed people
what patients with a sore throat need admission/ referral
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
what causes the vast majority of sore throats
viruses- dont give antibiotics
what is the most common cause of a bacterial sore throat
strep pyogenes (group A or group B haemolytic strep)
what are the clinical features of strep pyogenes throat infection
acute follicular tonsillitis
what is the treatment for strep pyogenes throat infection
penicillin
describe the features of strep pyogenes
gram positive cocci chains
beta haemolysis
what are the complications of strep pyogenes infection
rheumatic fever (3 weeks post sore throat, fever, arthritis, pancarditis) glomerulonephritis (1-3 weeks post sore throat, haematuria, albuminuria, oedema)
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
centor and fever PAIN criteria
what should you do if someone is immunosuppressed an gets a throat infection
do FBC, referral, consider antibiotics
what can cause neutropenia
carbimazole chemo asplenia leuaemia aplastic anaemia HIV
when in throat infections should you consider giving phenoxymethylpenicillin for a throat infection
if fever pain score of 4/5
centor score of 3/4
what are the clinical signs of diptheria
severe sore throat with a grey white membrane across the pharynx (pseudomembrane)
what cause the majority of the disease in diptheria
the exotoxin produced by the bacteria is cardiotoxic and neurotoxic
what prevents diptheria
vaccine- toxoid vaccine
what is the treatment for diptheria
antitoxin (most important) and supportive (maintain the airway)
pencillin/ erythtomycin
what are the features of infective mononucleosis
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
what will there be presence of in mononucleosis on blood films
atypical lymphocytes
what are the complications of mononucleosis
anaemia thrombocytopenia splenic rupture (avoid contact sports) upper airway obstruction risk of lymphoma
what is the treatment for mononucleosis
self limiting best rest paracetamol avoid sport antivirals not effective corticosteroids may have a role in some complicated cases
should you give steroids to help viruses
NO
how do you confirm mono
epstein barr virus IgM
heterophile antibody
blood count and film
liver function tests
what infections present similarly to mono
cytomegalovirus
toxoplasmosis
primary HIV infection
what are the clinical signs of candida/thrush
white patches on red, raw mucous membranes in throat/ mouth
what causes candida
candida albicans
endogenous (post anitbiotics, immunosuppressed, smokers, inhaled steroids)
what is the treatment for candida
nystatin or fluconazole
when should you investigate candida
if recurrent (suggests somethings wrong with T cells)
what is acute otitis media
an upper resp infection involving the middle ear by extension of infection up the eustachian tube
how does acute otitis media present
with ear ache
what are common infections of the middle ear
often viral with bacterial secondary infection
most common bacterial= haemophilus influenzae, strep pneumoniae, strep pyogenes
can you get samples for diagnosis in otitis media
only if eardrum has been perforated
what is the treatment for infections of the middle ear
80% resolve without antibiotics
1st- amoxicillin
2nd-erthryomycin
what is malignant otitis externa
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
what are the symptoms and signs of malignant otitis
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
what are the risk factors for malignany otitis
diabetes, radiotherapy to head and neck
what investigations to diagnose malignant otitis
PV, CRP, imaging, biopsy
IMPORTANT what are the side effects of quinolones
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
how do you treat malignant otitis
gentamicin 3x a day IV
what is otitis externa
inflammation of the outer ear canal
what are the clinical signs of otitis externa
redness, swelling of ear canal
itchy
sore
discharge/ increased amounts of ear wax- affects hearing
what commonly causes otitis externa
staph aureus
proteus spp
pseudomonas aeruginosa
associated with swimmers
fungal causes:
aspergillus niger
candida albicans
what is the management for otitis externa
topical aural toilet
swab in unresponsive/ severe cases
treatment depends on culture
what are the features acute sinusitis
mild discomfort over frontal/ maxillary sinuses due to congestion
seen in patients with URTI (viral)
what indicates a secondary bacterial infection in acute sinusitis
severe pain and tenderness with purulent nasal discharge
what is the treatment for acute sinusitis
usually lasts 2.5 weeks
antibiotics only for severe/ deteriorating cases
1st line phenomethylpenicillin
2nd line doxycycline (not in children)
