ENT Microbiology Flashcards
What generally is responsible for causing inflammation of the throat and pharynx?
What are some common causes of a sore throat?
what is the age bracket thaty sore throats usually happen in?
Infectious causes (2/3rd viral)
(non-infectious causes are rare)
common cold, influenza, strep infection
5-24 year olds
If sore throat and lethargy persist into the second week, and if the patient is 15-25 years old, what should be suspected?
What is this caused by?
Infectious mononucleosis (glandular fever)
Epstein barr virus `
What is the most common viral cause of a sore throat
Influenza and primary herpes simplex
Which pathogen causes infectious mononucleosis? what is this infection also known as?
What are some complications of a sore throat?
What is teh triad of symptoms for this?
Epstein barr virus - glandualr fever - the kissing disease
Ottis media (most common), peritonsilar abcess (quinsy) and parapharyngeal abcess
What is the most common cause of a bacterial sore throat?
what is the clinical manifestation?
What is the treament?
Streptococcus pyogenes
acute follicular tonsilitis
penicillin
What causes the beta haemolysis associated with S. pyogenes?
Is strep pyogenes gram +ve or neg?
LMW toxin diffusing out of the colonies
Gram positive cocci in chains
What are some late complications of strep pyogenes infection?
What scoring system is used in the diagnosis of GAS?
Rheumatic fever - 3 weeks post sore throat
glumerulonephritis - 1-3 weeks post sore throat
Centor criteria: one point for each
- tonsillar exudate
tender anterior cervical lymph nodes
history of fever
absence of cough
if all 4 = 52% risk of having the bacteria
FEVERpain score can also be used (look this up)
the antiboitc that is used is phenoxymethylpenicillin
What is “quinsy”?
Peri-tonsillar abscess
When will quinsy normally occur?
Usually a complication of tonsillitis
Streptococci most frequently cause unilateral infection in the palatine tonsils
What is Lemierre’s syndrome?
An infection, most commonly by F. necrophorum, of the posterior compartment of the lateral pharyngeal space as a complication of a bacterial sore throat infection in young, otherwise healthy adults
It involves a triad of symptoms:
- Pharyngotonsillar or odontogenic infection
- Lateral pharyngeal space invasion leading to internal jugular vein thrombosis
- Metastatic disease (sepsis or lung involvement)
(it is also known as human necrobacillosis and postanginal sepsis)
Which condition may result as a complication of an inadequately treated Streptococcus throat infection?
Rheumatic fever
What are the key symptoms of Rheumatic fever?
- Fever
- Arthritis
- Pancarditis
Which condition involving the kidneys can become a late complication of a streptococcus throat infection?
Glomerulonephritis
(presents with haematuria, albuminuria and oedema)
What is the treatment for a bacterial sore throat caused by S. pyogenes?
Penicillin
Which pathogen causes diptheria? - diptheria comes from the latin word leather (refers to the tough pharyngeal membrane that develops at the back of the throat)
Corynebacterium diphtheriae
How does diptheria affect the posterior pharynx?
Causes severe sore throat
Grey/white membrane across pharynx
produces a potent exotoxin which is cardiotoxic and neurotoxic
What is the treatment for diptheria?
Antitoxin and supportive penicillin/erythromycin
(it is vaccine preventable and rare in the UK)
How does candida present in the throat and mouth?
White patches in red/raw mucous membranes
What causes thrush?
clinical manifestations?
Candida albicans (endogenous)
white patches on red, raw mucous membranes in throat
How can thrush be treated?
Nystatin
What is acute otitis media?
URTI involving middle ear
This happens as the infection passes via the Eustachian tube
How doe acute otitis media typically present?
- Infants/children
- Ear ache
- Discharge (if ear drum ruptures)
(hearing loss, fever and lethargy are also common)
Which bacteria are most commonly found to infect the middle ear?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Streptococcus pyogenes
- Moraxella catarrhalis
How can middle ear infections be diagnosed?
Only by discharge swabs - only when the eardrum perforates
How are infections of the middle ear treated?
Most resolve spontaneously
1st line - Amoxicillin
2nd line - Erythromycin
What is acute sinusitis?
Mild discomfort over the frontal or maxillary sinuses due to congestion often seen in patients with URTI
What does severe pain and tenderness with purulent nasal discharge indicate in a patient with acute sinusitis?
Secondary bacterial infection
Which bacteria commonly affect the sinuses in acute sinusitis
- Streptococcus pneumoniae
- Haemophilus influenzae
- Streptococcus pyogenes
- Moraxella catarrhalis
How long does acute sinusitis usually last?
2.5 weeks
When should antibiotics be used for acute sinusitis?
Severe or deteriorating cases lasting longer than 10 days
What is the definition of chronic sinusitis?
Sinusitis lasting longer than 4 weeks
(Acute is < 4 weeks)
What is the treatment for acute sinusitis?
1st line - Penicillin
2nd line - Doxycyline (clarithromycin in children)
Why must doxycyline be avoided in children?
It is toxic to growing teeth and bones
What is the term given to inflammation of the outer ear canal?
what is the most common cause?
Otitis externa - aka swimmers ear
acute bacterial infection
Why may hearing be impacted in otitis externa?
what are the bacterial causes?
fungal?
treatment?
Discharge and increased amounts of ear wax may be associated
staph aureus (most common)
proteus spp
pseudomonas aeruginosa (most common_
Fungal = aspergillus niger, candida albicans - mainstay of treatmetn is cleaning and topical antifungal therapy
treatment - just a washout of the ear;
In the early stages otitis externa will be red and _______
how do you define acute?
In the early stages otitis externa will be red and itchy
also there will be swelling
can become sore and painful
lasting three weeks or less
What is malignant otitis?
Extension of otitis externa into the bone surrounding the ear canal
Why is malignant otitis a fatal condition without treatment?
The mastoid and temporal bones are affected by osteomyelitis which will also begin to involve the meninges
What are the symptoms and signs for malignant otitis?
- Pain and headache (worse than signs would suggest)
- Granulation tissue at bone/cartilage junction of ear canal
- Facial nerve palsy
Which pathogen usually causes malignant otitis?
Pseudomonas aeruginosa
What are the key risk factors for malignant otitis?
Diabetes
Radiotherapy to the head/neck
What are the common causes for otitis externa?
Bacterial:
- S. aureus
- Pseudomonas aeruginosa
Fungal:
- Aspergillus niger
- Candida albicans
What should be avoided when affected by otitis externa?
Swimming
(there ear is constantly wet damp with regular swimming increases likelyhood of bacterial growth)
How should fungal otitis externa be treated?
Topical clotrimazole
How is otitis externa treated if the cause is bacterial?
Gentamicin (0.3%) drops
What is the classic triad of symptoms seen in most patients with infectious mononucleosis?
- Fever
- Pharyngitis
- Lymphadenopathy
Where are the lymph nodes often most prominent in infectious mononucleosis?
Neck (cervical)
Why are ampicillin and amoxicillin not recommended to treat infectious mononucleosis?
Cause diffuse rash in many patients
Which LFT is most raised in infectious mononucleosis?
ALT
Which organs are most commonly affected by infectious mononucleosis?
- Respiratory tract
- Skin (rash (25%))
- Liver (jaundice/hepatitis in few patients)
- Spleen (splenomegaly (50%)) - avoid sport for 6 weeks incase of rupture
- Palate (palatal petechiae)
- Blood (leucocytosis, presence of atypical lymphocytes in blood film)
Atypical lymphocytes can occur with any viral infection, what makes this sign different in infectious mononucleosis?
It occurs in around 15% of lymphocytes
How long does infectious mononucleiosis normally last?
2-4 weeks
Why should sport be avoided for 6 weeks in infectious mononucleiosis?
Splenomegaly many occur with the condition and sport may induce a rupture
What are the main complications associated with infectious mononucleiosis?
- Anaemia
- Thrombocytopenia
- Splenic rupture
- Upper airway obstruction
- Increased risk of lymphoma
What is different about Epstein barr infection in those in early childhood versus those over 10 years old?
Primary infection in early childdhood is unlikely to cause infectious mononucleiosis, whereas after 10 years it is likely
What are the two phases for EBV acquisition?
how is this confirmed in the lab?
1-6 years
14-early 20s
IgM epstein-barr virus positive
Why may EBV induce autoimmunity?
The virus replicates in B cells which leads to abnormal antibody production
What is the treatment for infectious mononucleiosis?
Bed rest
No sport
Paracetamol
Corticosteroids in severe cases
Which pathogens can cause similar infection to infectious mononucleiosis?
- Cytomegalovirus
- Toxoplasmosis
- Primary HIV infection
How can infectious mononucleiosis be differentiated from primary HIV infection?
Risks in history
Presence of diarrhoea (in HIV)
Which type of virus commonly causes oral lesions?
Herpes simplex type 1
What is HSV2 more commonly associated with?
herpes that appear in the genital area
What is the percentage of adults that have been infected by the herpes virus?
70% of adults
how is herpes transmitted?
gential or oral contact
What are some clinical manifestations of herpes?
frequently asymptomatic
recurrent/perioral lesions (cold sores)
genital lesions or occular infections (herpetic keratitis)
How can primary gingivostomatitis be treated?
what age category usually gets this disease?
What are some of the symptoms
Aciclovir
It is a disease of pre-school children
Multiple painful oral lesions - with local lympahdenopathy
Why is HSV1 likely to reactivate?
Inactive virus can remain latent in trigeminal ganglia
What is herpetic whitlow?
Lesion (whitlow) on a finger or thumb caused by the herpes simplex virus - infected by a break in the skin.
Which pathogen causes herpangina?
What are the clinical manifestations?
Coxsackie A viruses
vesicles/ ulcers on soft palate - fever and painful papulo-vesiculo-ulcerative oral enanthem
Which pathogen causes hand, foot and mouth disease?
Where is an outbreak common and how is it tested for clincially?
Clinical symptoms?
Coxsackie viruses
Common outbreaks within families and it is diagnsoed by PCR
Oral enanthem and macular/maculopapular rash of the hands and feet
Which systemic diseases may cause recurrent apthous ulcers?
What are they?
Where are they confied to?
Behcet’s disease
Gluten sensitive enteropathy or IBD
Reiter’s syndrome
Drugs reactions
Skin diseases (lichen planus, pemphigus or pemphigoid)
painful oral lesions that appear as localised round, yellowish central exudate
Confined to the mouth - each ulcer lasts usually less than 3 weeks
Which pathogen cause syphilis?
Where is the most common site?
Treponema pallidum
Genital but oral and pharyngeal lesions can be the site of entry
- if left undiagnosed can lead to secondary and tertiary syphillis
How does primary syphilis present?
Chancre (painless ulcer) at site of entry
How are cold sores reativated?
What is the treatment?
From nerves and this causes active infection
- aciclovir
What do I mean when I say patients that experince a reactivation of HSV1 experince prodromo symptoms 24 hrs before onset of cold sore
Pain, burning and tingling
When would a sample be taken from a pateint that has suspected Hepes simplex virus?
How is it diagnosed?
new mucosal or cutaneous lesions or recurrent muscosal or cutaneous leesions of unclear eitology
PCR test done on DNA testing
Which pateints should be treated with HSV1?
Give an example of a drug that causes neutropenia?
Carbimazole
