Microbiology of ENT Infections Flashcards
which type of herpes simplex virus causes oral lesions?
type 1
how is herpes simplex virus acquired and which type is usually acquired in childhood?
through saliva contact
type 1 acquired in childhood
describe the features of primary HSV1 infection?
pre-school children systemic upset lips,buccal mucosa, hard palate affected vesicle 1-2mm ulcers fever local lymphadenopathy 3 weeks recovery spread beyond mouth
how is HSV1 managed?
aciclovir
what happens after primary HSV1 infection?
latency
inactive for of virus in sensory nerve cells
can reactivate to re-infect mucosal surface
what causes a cold sore?
reactivation of HSV1 from nerves which causes active infection
how are cold sores managed?
aciclovir
does HSV1 always reactivate after primary infection?
no
only half
intra oral vs oral herpetic lesions?
oral = HSV1 intra-oral = HSV
what coloured tube is use for viral PCR?
red
what causes herpangina?
coxackie virus (not HSV)
how does herpangina present?
vesicles/ulcers on soft palate
similar age range to primary HSV gingivostomatitis
how is herpangina diagnosed?
clinically or viral PCR
what causes hand foot and mouth disease?
coxackie viruses (enteroviruses)
features of hand foot and mouth?
sore throat
mouth ulcers
rash
blisters on hands and feet
diagnosis of hand foot and mouth?
clinically or viral PCR
main feature of primary syphilis?
chancre (painless ulcer at site of entry of the bacterium)
most common site = genital
oral lesions are possible
what bacteria causes syphilis?
treponema pallidum
what are apthous ulcers?
non-viral, self limiting recurring painful ulcers of the mouth that are round or ovoid and have inflammatory halos
in the absence of systemic disease
confined to mouth
begin in childhood and tend to abate in 3rd decade
each ulcer lasts less than 3 weeks
5 causes of recurrent ulcers associated with systemic disease (non-viral)?
behcets disease gluten sensitive enteropathy or inflammatory bowel disease reiter's disease drug reactions skin diseases
clinical presentation of acute pharyngitis?
inflammation of the part of the throat behind the soft palate (oropharynx)
clinical presentation of tonsillitis?
inflammation of the tonsils
when may mononucleosis/Epstein barre virus (glandular fever) be suspected?
if sore throat and lethargy persist into 2nd weeks, especially if person is 15-25 yrs old
non-infectious causes of sore throat?
GORD chronic irritation from smoking alcohol hay fever (look for red flags)
primary care management of sore throat?
history and clinical exam
throat swabs not routinely carried out in primary care
how is sore throat managed generally?
usually self limiting
- usually within 3 days - 1 week
4 common secondary causes of sore throat?
otitis media (most common)
peri-tonsillar abscess
para-pharyngeal abscess
mastoiditis
which cases of sore throat may need referral/admission?
suspicion of throat cancer (persistent with neck mass)
sore throat lasting over 3-4 weeks with pain on swallowing or dysphagia for more than 3 weeks
red or red/white patches or ulceration or swelling of the oral/pharyngeal mucosa for >3 weeks
stridor/respiratory difficulty is an emergency
what does penicillin treat?
strep pyogenes
self care for sore throat?
regular analgesia medicated lozenges avoid hot drinks fluid intake mouthwash/spray
do most sore throats needs antibiotics?
no
2/3rds are viral
most common bacterial cause of sore throat?
strep pyogenes (group A beta haemolytic strep)
clinical presentation of strep pyogenes sore throat?
acute follicular tonsilitis
management of strep pyogenes sore throat?
penicillin
describe strep pyogenes?
gram +ve cocci chains
beta haemolysis
name 2 late complications of strep pyogenes infection
rheumatic fever (fever, arthritis and pancarditis) glomerulonephritis (haematuria, albuminuria and oedema)
what is CENTOR criteria?
scoring system for likelihood of group A beta haemolytic strep cause of sore throat
what are the components of CENTOR criteria?
tonsillar exudate tender anterior cervical lymph nodes history of fever (>38) absence of cough one point each (out of 4 points) - 0, 1 or 2 = 3-17% risk - 3 or 4 = 32-56% risk
management of sore throat for people who are taking DMARDs?
FBC (withhold DMARD while awaiting result)
seek urgent specialist advice/referral if patient has low WCC or deteriorates
- give symptomatic relief and consider an antibiotic (take into account DMARD interactions)
what can cause neutropaenia?
drugs like carbimazole
chemotherapy
known/suspected leukaemia
immunosuppression of any kind
management of sore throat in co-existent neutropenia?
urgent FBC
withhold causative drug until result is back
consider antibiotic
when may phenoxymethylpenicillin be considered?
fever PAIN score 4 or 5
CENTOR 3 or 4
what bacteria causes diptheria?
Corynebacterium diptheriae
clinical presentation of diptheria?
severe sore throat with grey-white membrane across the pharynx
- bacteria produces exotoxin which is cardiotoxic and neurotoxic
can diptheria be prevented?
yes
vaccine
how is diptheria managed?
antitoxin and supportive
penicillin/erythromycin
presentation of infectious mononucleitis (glandular fever)?
fever enlarged lymph nodes sore throat, pharyngitis, tonsillitis malaise lethargy jaundice/hepatitis rash splenomegaly palatal petechiae (non blanching palatal rash)
cause of infectious mononucleosis?
Epstein barre virus
part of the herpes family
haematology of mononucleosis?
leucocytosis (lymphocytosis)
presence of atypical lymphocytes in blood film
possible complications of mononucleosis?
anaemia, thrombocytopaenia
splenic rupture
upper airway obstruction
increased lymphoma risk
are steroids given for viruses?
no
generally steroids make viruses worse
what are the 2 phases of primary infection with Epstein barr virus?
primary infection in childhood rarely results in symptoms
primary infection in those >10 often causes infectious mononucleosis
management of mononucleosis?
bed rest paracetamol avoid sport (spleen rupture) antivirals not effective steroids used very rarely
lab confirmation of EBV?
EBV IgM heterophile antibody - paul bunnel test - monospot test blood count and film LFTs
what 3 illness can cause similar illness to EBV?
cytomegalovirus
toxoplasmosis
primary HIV
clinical presentation of candida?
white patches on red, raw mucous membranes in throat/mouth
what can cause candida in the mouth?
endogenous post antibiotics immunosuppression smokers inhaled steroids
treatment of candida?
nystatin or fluconazole
what is acute ottis media?
URTI involving middle ear by extension of infection up the eustachian tube
usually in infants and children
presents with earache
most common causes of middle ear infection?
usually viral with secondary bacterial infection
most common bacteria = haemophilus, strep pneumoniae and strep pyogenes
diagnosis of middle ear infection?
swab of pus if eardrum perforates
otherwise samples cant be obtained
how is middle ear infection managed?
80% resolve within 4 days without antibiotics
1st line = amoxicillin
2nd line = erythromycin
what is malignant otitis?
extension of otiyis externa into the bone surrounding the ear canal
fatal without treatment
how does malignant otitis present?
pain and headache (more severe than clinical signs would suggest)
granulation tissue at the bone -cartilage junction of the ear canal
exposed bone in the ear canal
facial nerve palsy (drooping face on side of lesion)
how is malignant otitis investigated?
PV raised CRP raised imaging biopsy culture (usually shows pseudomonas aeriginosa)
risk factors for malignant otitis?
diabetes
radiotherapy to head and neck
what is otitis externa and how does it present?
inflammation of outer ear canal redness and swelling of skin of ear canal may be itchy can be sore and painful can have discharge or increased ear wax - hearing can be affected if blocked
bacterial causes of otitis externa?
staph aureus
proteus spp
pseudomonas aerginosa
fungal causes of otitis externa?
aspergillus niger
candida albicans
management of otitis externa?
topical aural toilet
swab to microbiology and antimicrobial prescription only for severe cases
- clotrimazole for aspergillus niger
- gentamicin drops
how does acute sinusitis present?
mild discomfort over frontal or maxillary sinuses due to congestion
severe pain and tenderness with purulent nasal discharge indicates secondary bacterial infection
seen in patients with viral URTIs
management of acuet sinusitis?
illness usually lasts 2.5 weeks
antibiotics if severe/deteriorating cases lasting over 10 days
1st line = phenoxymethylpenicillin
2nd line = doxycycline (not in children)
Fever PAIN criteria?
likelihood of group B strep
what are the components of fever PAIN criteria?
Fever (last 24 hrs) Purulence Attend rapidly (within 3 days) v. Inflammed tonsils No cough/coryza one point each - 0 or 1 = 13-18% risk - 2 or 3 = 34-40% risk - 4 or 5 = 62-65% risk
