7: Microbiology Flashcards
A sore throat with stridor or respiratory distress is an indication for what?
Admission
Why shouldn’t you examine an inflamed throat?
Could make inflammation (i.e epiglottitis) worse and constrict throat
What throat infections cause pain at the back of the mouth?
Acute pharyngitis
Tonsilitis
What tends to cause throat infections?
Viruses
Bacteria
In which groups do acute throat infections usually occur?
Younger people (< 25 years)
Acute throat infections are often complicated by which diseases?
Otitis media
Quinsy
Parapharyngeal abscess
Mastoiditis
What is the course of most acute throat infections?
Resolve within 1 week - self-limiting
Should acute throat infections be swabbed?
Not routinely
What should you suspect if a sore throat and lethargy last more than 2 weeks in a young person?
Glandular fever
(infectious mononucleosis)
If someone has a persistent sore throat and a neck mass, what should you suspect?
Pharyngeal cancer
Which score is used to predict which acute throat infection patients would actually benefit from antibiotics?
Centor clinical prediction score
The vast majority of sore throats (do / do not) require antibiotics.
Why?
do not
viral
What are the most common bacterial causes of sore throat?
GAS
Strep. pyogenes
gram +ve chains
How would a Strep. pyogenes throat infection be treated?
Penicillin
What are rare complications of GAS throat infections causing:
a) fever, arthritis
b) acute renal failure?
a) Rheumatic fever
b) Glomerulonephritis
Which organism produces a grey white membrane across the throat which is an exotoxin?
What is the disease called?
Corynebacterium diptheriae
Diptheria
What is the classical feature of diptheria?
Pseudomembrane
Is diptheria common in the UK?
No
What sort of vaccine is given for diptheria?
Inactivated vaccine
How is diptheria treated?
Supportive therapy
Diptheria antitoxin
Penicillin
What causes oral thrush?
Candida
What does oral thrush look like?
White patches on inflamed membranes in throat and mouth
How is oral thrush treated?
Nystatin (anti-fungal)
What is acute otitis media?
What is the main symptom?
Middle ear infection
Earache
What commonly causes otitis media?
Most are VIRAL
Bacterial - Strep. pneumoniae, H. influenzae, Strep. pyogenes
In which situation only can you obtain a swab of pus in otitis media?
Perforation of tympanic membrane
which is obviously really bad
How is otitis media treated?
Supportive (viral)
Bacterial: amoxicillin > erythromycin
What is acute sinusitis?
Mild discomfort over sinuses often seen in URTI
When is acute sinusitis treated?
Secondary bacterial infection
Severe pain
How is secondary bacterial sinusitis treated?
Penicillin IV
Doxycyline BUT NOT IN CHILDREN
What is otitis externa?
Inflammation of external acoustic meatus (ear canal)
What are the symptoms of otitis externa?
Inflammation of ear canal
Pain
Itch
Discharge
Loss of hearing
What is malignant otitis externa?
Otitis externa which has turned into an osteomyelitis of mastoid and temporal bones
Which bacteria usually causes malignant otitis externa?
Pseudomonas aeurginosa
Which cranial nerve can be damaged by malignant otitis externa?
CN VII
Facial nerve palsy
What bacteria cause otitis externa?
Staph. aureus
Pseudomonas
People who ___ a lot can get otitis externa.
swim
What is infectious mononucleosis?
Who gets it?
Glandular fever
Young adults
What are the symptoms of infectious mononucleosis?
Fever
Enlarged lymph nodes
Sore throat (throat infection, pharyngitis, tonsilits)
Malaise, lethargy (lacking energy)
What sign on histology is pathognomic of glandular fever?
Atypical T lymphocytes:
massive
blue stipled cytoplasm
smaller nucleus than normal (should take up the whole cell)
What is the course of glandular fever?
3+ week duration but self-limiting
What are haematological complications of glandular fever?
Haemolytic anaemia
Thromocytopenia
production of autoantibodies against RBCs and platelets
Splenic rupture
What can enlarged tonsils cause in severe glandular fever?
Upper airway obstruction
People who have had glandular fever are at increased risk of which blood cancer?
Lymphoma
Which virus causes glandular fever?
Epstein Barr virus (EBV)
What happens to patients
a) in early childhood
b) > 10 years old
who are exposed to EBV?
a) Rarely mono
b) Often mono
How is glandular fever treated?
Bed rest
Avoid sport
Paracetamol
Are antivirals given for glandular fever?
No, not effective
What drug can be given for complications of glandular fever?
Steroids
What investigations confirm EBV infection in glandular fever?
EBV IgM (early infection)
Specific antibody tests (e.g monospot)
Blood films (for increased numbers of lymphocytes)
LFTs (for jaundice)
What should be checked in pregnant women with glandular fever?
Causal organism
(because CMV, toxoplasma can cause birth defects)
If someone has glandular fever and tests negative for EBV, what important virus should they be tested for?
HIV
Which type of HSV causes mouth ulcers?
HSV Type 1
What disseminated skin infection are people with HSV1 susceptible to?
Eczema herpeticum
How does HSV1 infection present on
a) primary infection
b) reactivation?
a) Gingivostomatitis
b) Cold sores
What are people given if they suffer from recurrent mouth ulcers due to HSV1 infection?
Aciclovir
Genital herpes is caused by both HSV1 and ___.
HSV2
What is herpetic whitlow?
Who tended to get them?
Cold sores on fingers due to contact with HSV1 mouth ulcers
Dentists
How is HSV infection confirmed in the lab?
Viral PCR
What is the name for viral infection causing vesicles and ulcers on the back of the throat?
What organisms cause it?
Herpangina
Coxsackie virus
What viral infection causes lesions on the hands, feet and mouth?
What causes it?
Hand, foot and mouth disease
Coxsackie virus
What are apthous ulcers?
Mouth ulcers which aren’t associated with infection
i.e they’re inflammatory
What organism causes syphilis?
Treponema pallidum
What is the painless ulcer caused by primary syphilis infection?
Chancre
