Microbiology of ENT infections Flashcards
When obtaining a throat swab, what should you try and do
Swab the tonsil and scripts on either side of the tonsil
What type of infection causes the majority of sore throats
Viral infection
What is the most common bacterial cause of a sore throat
Streptococcus pyogenes (Group A strep)
What is the treatment for a group A strep
Oral penicillin (NOT amoxicilin) if penicillin allergic, give clarithryomycin
why should amoxicillin not be given for a bacterial sore throat
It can cause patients to come out in a rash if they have glandular fever
What are the 4 criteria in the ENT infection management guidance for sore throats
Fever pussy discharge inflamed lymph nodes NO cough BACTERIAL
If there is a cough present, what does this suggest
It is more likely to be a viral cause
Describe the histological appearance of streptococcus pyogenes
Gram positive cocci chains Beta haemolysis (complete)
What are some acute complications of a streptococcal sore throat
peritonsillar abscess (quinsy
Sinusitis / ottis media
scarlet fever
What might a quinsy require
surgical drainage
What infection control measures are required for a strep pyogenes quinsy in hospital
Standard infection control
contact precautions
risk assess need for droplet precautions (may need masks for being around patients that are sneezing and coughing)
What are some late complications of a streptococcal sore throat
Rheumatic fever
Glomerulonephritis
Describe the symptoms of Rheumatic fever
3 weeks post sore throat fever arthritis pancarditis endocarditis heart failure
Rare in the UK
Describe the symptoms of Glomerulonephritis
1-3 weeks post sore throat Haematuria albuminuria oedema Blood and protein in the urine
Why do these late complications of a streptococcal sore throat occur
Due to cross reacting antibodies reacting
What is a major symptom of diphtheria
A hugely swollen throat
What is the causative organism of diphtheria
Corynebacterium diphtheriae
What are the clinical symptoms of diphtheria
Severe sore throat with swelling around the neck with a grey white membrane across the pharynx.
Describe the appearance of Corynebacterium diphtheriae on gram film
Small gram positive rod
What is a major complication of diphtheria and how does this arise
Respiratory arrest in children
the throat is being completely blocked
Describe the vaccine for diphtheria
cell -free purified form of the toxin
Very safe and has almost ruled out diphtheria in the UK
What is the treatment for Diphtheria
Antitoxin and supportive and penicillin/ erythromycin (e.g. intubation and ventilation)
What is the causative organism of thursh in the mouth
Candida albicans (yeast infection)
What is the clinical appearance of thrush
White patches on red, raw inflamed mucous membranes in the throat / mouth
What is the treatment for thrush
Nystatin suspension topically on the tongue
What is acute otitis media
An URI involving the middle ear by extension of infection up the eustachian tube
Who is most likely to develop acute otitis media and how do they present
Disease of infants and children
Present with extreme earache
Why are children more prone to acute otitis media
The eustachian tube tends to be quite flat and does not drain as well as in adults
What are the most common bacteria to cause an infection of the middle ear
Haemophilus influenzae
Streptococcus pneumoniae
Streptococcus pyogenes
How can we make a diagnosis of a middle ear infection
Can only do this if the ear drum has perforated
What is the treatment for a middle ear infection
80% resolve themselves in 4 days (i.e. just viral)
What do the ENT infection management guidelines say in relation to treating middle ears
Amoxicillin (not penicillin) should be considered for those presenting bilaterally and for children under the age of 2
or if there is obvious pus coming from the ear canal
How does acute sinusitis present
mild discomfort over frontal or maxillary sinuses due to congestion often seen in patients with UTVI
Severe pain and tenderness with purulent nasal discharge indicates a secondary bacterial infection
What is the treatment for acute sinusitis
If no complications then avoid antibiotics
Where indicated penicillin
2nd line doxycycline (not in children)
Why is doxycycline not given to children
Stains the teeth and the bones
Who are unlikely to develop acute sinusitis
Children
What is otitis externa
Inflammation of the outer ear canal
What is the clinical presentation of otitis externa
Redness and swelling of the skin of the ear canal
May be itchy (in early stages)
can become sore and painful
may be a discharge or increased amounts of ear wax
Hearing can be affected
What are the main bacterial causes of otitis external
Staphylococcus aureus
Proteus spp and other cloakrooms
Pseudomonas aeuginosa
Who is most likely to develop otitis external
Swimmers
What are the 2 fungal causes of Otitis external
Aspergillus niger
Candida albicans
What do fungal organisms do
They don’t invade and just feed on the debris and wax in the EAM
What is the best treatment for fungal otitis external
Clean out the ear as much as possible and get rid of debris
What should be given for a Pseudomonas infection of the external ear
Topical gentamicin
What is another term for infection mononucleosis
Glandular fever
How does glandular fever usually present
Fever Enlarged lymph nodes sore throat pharyngitis tonsilitis malaise lethargy
What is the classic triad of symptoms in glandular fever
Fever
pharyngitis
lymphadenopathy
What are some unusual signs of glandular fever
Jaundice / hepatitis
Lacy, red, rash (amoxicillin makes worse)
Splenomegaly
Palatal petachiae (pin point bruising of hard palate)
What are the complications of glandular fever
Self limiting anaemia, thrombocytopenia Splenic rupture upper airway obstruction doubled risk of lymphoma
What is the cause of glandular fever
Epstein Barr virus (EBV)
What are the two phases of primary infection with EBV
Primary infection nearly childhood rarely results in infectious mononucleosis
Primary infection in those >10 often causes infectious mononucleosis
What is the therapy for glandular fever
bed rest
paracetamol
avoid sport (US to exclude splenomegaly before contact sport)
Corticosteroids possibility
How can we make a laboratory confirmation of glandular fever
Epstein -baBarr virus IgM
What are some other causes of similar illness
Cytomegalovirus
Toxoplasmosis
Primary HIV infection
What do you have to watch out for when testing for a primary HIV infection
May be falsely negative for about a week
What are the types of Herpes simplex virus
Types 1 and 2
When is type 1 acquired
Childhood
What does HSV1 cause
Oral lesions
Infection is through saliva
Who can be affected by primary gingivostomatitis
Pre-school children
What areas of the body are affected by primary gingivostomatitis
Lips
buccal mucosa
hard palate
What is the cause of primary gingivostomatitis
HSV1
What are the symptoms of primary gingivostomatitis
Fever
local lymphadenopathy
What is the treatment for primary gingivostomatitis
Aciclovir
How do cold sores end up reappearing
The virus travels up through the nerve axons and becomes latent in the trigeminal ganglia and the virus becomes inactive.
Periodically it can reactivate and go back down the axon and re-infect mucosal surfaces
What does acyclovir not prevent
Latency
What might cause the HSV1 to reactivate
Sunburn
Immunosuppressed
Hormonal changes
How many infected people get clinical recurrences of cold sores
Half of infected people
Who is at risk of Herpetic whitlow
Dentists and anaesthetics
Using gloves is essential in prevention
Where does Herpetic whitlow affect
Between the nail and normal skin
How is a confirmation of HSV made
Swab of the lesion and viral DNA by PCR
In the brain, what can Herpes simplex cause
Encephalitis leading to necrosis of the temporal lobe
how does herpes simplex encephalitis present
Fever and a changed mental state e.g. sleepy, change in personality or grand mal seizure
What causes Herpangina
Coxsackie viruses
How is a diagnosis of Herpangina made
Clinically or by PCR test of swab in viral transport medium
How does Herpangina present
Shallow ulcers on the roof of the mouth
soft palate
What causes Hand, foot and mouth disease
Coxsackie virus
What is the clinical presentation of hand, foot and mouth disease
Vesicles on the hand, feet and buttocks
Often family outbreaks
What are apthous ulcers
Non viral, self limiting, recurring painful ulcers on the mouth that are round or ovoid and have inflammatory hals
How long does each apthous ulcer last
Less than 3 weeks
What organism causes Primary syphilis
Treponema pallidum
Where is the most common site of primary syphilis
Genital but oral lesions can be the site of entry
What could happen if primary syphilis was left undiagnosed and untreated
Can progress to secondary and tertiary syphilis
What are some symptoms of Behcet’s disease
Recurrent oral ulcers
Genital ulcers
Uveitis
Common in Middle east and asia
What other systemic diseases can cause apthous ulcers
Beech's disease Gluten sensitive enteropathy IBD Eritrea's disease Drug reactions Skin diseases
