microbiology Flashcards
what are the features of herpes simplex virus 1?
Type 1 acquired in childhood
HSV1 is cause of oral lesions
70% UK adults have been infected
Transmitted via infected oral secretions during close contact
Frequently asymptomatic
Clinical manifestations varies
what are the features of primary gingivostomatitis?
caused by HSV1
Disease of pre-school children
Primary infection
Systemic upset
affects Lips, buccal mucosa, hard palate
Vesicles 1-2mm
Ulcers
how is primary gingivostomatitis treated?
aciclovir
is herpes forever?
yes
what are the features of herpes cold sores?
Reactivation from nerves causes active infection
Various stimuli
Aciclovir therapy or suppression
Not all reactivations are symptomatic
Aciclovir does not prevent latency
name a complication of HSV?
encephalopathy leading to temporal lobe necrosis
how is HSV confirmed?
swab lesion then detection of viral DNA by PCR
which virus causes herpangina?
coxsackie virus
what are the features of herpangina?
Vesicles/ulcers on soft palate
Similar patient age range to 1ry HSV gingivostomatitis
how is herpangina diagnosed?
clinically or PCR
what causes hand, foot and mouth disease?
coxsackie virus
what is an alternative kind of mouth ulcer?
apthous ulcer
what are the features of an apthous ulcer?
non-viral and self limiting
recurring and painful
confined to mouth
no systemic disease
begin in childhood, usually go by 30s
each ulcer lasts less than 3 weeks
what are some recurrent ulcers associated with systemic disease?
Behcets disease
IBS
reiters disease
skin disease
what are the features of behcets disease?
Recurrent oral ulcers
Genital ulcers
Uveitis.
It can also involve visceral organs such as the gastrointestinal tract, pulmonary, musculoskeletal, cardiovascular and neurological systems
Commonest in Middle East and Asia
what is the clinical pres of a sore throat?
pain at the back of mouth
what is the clinical pres of acute pharyngitis?
inflammation of the part of the throat behind the soft palate (oropharynx)
what is the clinical pres of tonsilitis?
inflammation of the tonsils
which scores are used to determine if abx should be prescribed in a sore throat?
feverPAIN and Centor clinical prediction
which disease should be considered if sore throat and lethargy persist in patient aged 15-25?
glandular fever (EBV)
what are some complications of tonsilitis and pharyngitis?
Otitis media (most common)
Peritonsillar abscess (quinsy)
Parapharyngeal abscess
Lemierre Syndrome (Suppurative thrombophlebitis of jugular
when should there be an imediate referral in sore throat?
Stridor, breathing difficulty, clinical dehydration, systemically unwell
how should a sore throat be managed?
Self Care advice: giving simple advice
Prescribing antibiotics ONLY where appropriate
Identify and manage immunosuppressed people
Identifying those who need admission/referral
-Throat cancer is suspected (persistent sore throat,
especially if there is a neck mass)
-Sore or painful throat lasts for 3 to 4 weeks. There is
pain on swallowing or dysphagia for more than 3
weeks
-Red, or red and white patches, or ulceration or
swelling of the oral/pharyngeal mucosa persists for
more than 3 weeks
-Stridor / respiratory difficulty is an emergency
which pathogen commonly causes a bacterial sore throat?
strep pyogenes (group A strep)
how is strep pyogenes treated?
penicillin
what type of bacteria is strep pyogenes?
gram positive cocci chains
beta-haemolysis (complete)
what are some late complications of strep pyogenes?
Rheumatic fever
-3 weeks post sore throat
-fever, arthritis and pancarditis
Glomerulonephritis
-1-3 weeks post sore throat
-haematuria, albuminuria and oedema
which drugs can cause neutropenia?
carbimazole
who is at risk of neutropenia?
people with chemotherapy, known/suspected leukaemia, asplenia, aplastic anaemia or HIV with low CD4, or on an immunosuppressant
how is neutropenia confirmed?
urgent FBC and withhold drug until results are available
seek imediate specialist advice
if feverPAIN score is 4/5 which drug should be considered?
phenoxymethylpenicillin
what happens to the throat in a diptheria infection?
the pseudomembrane in the posterior pharynx can become very large and may obstruct airway
how is diphtheria diagnosed?
a sample of the resp tract secretions
how is diphtheria treated?
antitoxin and supportive
penicillin/erythromycin
what are the symptoms of infectious mononucleosis (glandular fever)
Disease of young adults
Fever
Enlarged lymph nodes
Sore throat, pharyngitis, tonsillitis
Malaise, lethargy
Jaundice/hepatitis
Rash
Haematology
Leucocytosis (lymphocytosis)
Presence of atypical lymphocytes in blood film
Splenomegaly
Palatal petechiae
what are the complications of infectious mononucleosis?
Protracted but self limiting illness
Anaemia, thrombocytopenia
Splenic rupture
Upper airway obstruction
Increased risk of lymphoma, especially in immunosuppressed.
what is the clincical pres of candida albicans (thrush)
white patches on red, raw mucous membranes in throat/ mouth
what can cause candida albicans?
endogenous (post antibiotics, immunosuppressed, smokers, inhaled steroids)
what is the treatment for candida albicans?
nystatin or fluconazole
what is acute otitis media?
An upper respiratory infection involving the middle ear by extension of infection up the Eustachian tube
Predominantly disease of infants and children
Presents with earache
what is an infection of the middle ear
usually viral with a secondary bacterial infection
which bacteria usually causes a middle ear infection?
Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes.
how is a middle ear infection diagnosed?
– swab of pus if eardrum perforates
how is a middle ear infection treated?
80% resolve in 4 days with no abx
first line- amox
second line- arythromycin
what is otitis externa?
inflammation of the outer ear canal
what are the clinical features of otitis externa?
Redness and swelling of the skin of the ear canal
It may be itchy (especially in the early stages)
Can become sore and painful
There may be a discharge, or increased amounts of ear wax
If the canal becomes blocked by swelling or secretions, hearing can be affected
what are the bacterial causes of otitis externa?
Staphylococcus aureus
Proteus spp
Pseudomonas aeruginosa
what are the fungal causes of otitis externa?
Aspergillus niger
Candida albicans
how is otitis externa managed?
Topical aural toilet
Swab to microbiology and prescription of antimicrobial reserved for unresponsive or severe cases
Treat depending on culture results
-Topical clotrimazole (trade name canesten)
-Gentamicin 0.3% drops
what is the first line abx in acute sinusitis?
phenoxymethypenicillin
second line- doxycycline
what usually causes acute sinusitis?
Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes
