Microbiology Flashcards
What are some causes of cold sores?
Reactivation from nerves causing active infection
Various stimuli
Acliclovir therapy or suppression
What is a major complication of the Herpes simplex virus ?
Herpes simplex encephalitis
How is a diagnosis of Herpes Simplex virus confirmed?
Swab lesion of virus transport medium
Detection of viral DNA by PCR
Which virus causes Herpangina?
Coxsackie viruses
How does Herpangina present?
Vesicles/ulcerd on soft palate
Which virus causes hand foot and mouth disease?
Cocsackie viruses
How does Behcet’s disease ulcers present?
Recurrent oral ulcers
Genital ulcers
Uveitis
Which scoring system is used to predict the likelihood of GRiup A Strep infection?
Fever PAIN criteria
What is the name if the bacteria that causes diptheria?
Corynebacterium diptheriae
How does diptheria present?
Severe sore throar with a grey white membrane across the pharynx.
The organism produces a potent exotoxin which is cardiotoxic and neurotoxic.
What is the treatment for diptheria?
Antitoxin and supportive
Penicillin/Erythromycin
What are the clinical features of glandular fever?
Fever
Enlarged lymoh nodes
Sore throat, pharyngitis, tonsillitis
Malaise, lethargy
Jaundice, hepatitis (complications)
What is the laboratory confirmation of Epstein Barr virus?
Epstein Barr virus IgM
Heterophile antibody
- Paul Bunnell test
- Monospot test
Blood count and film
Liver function test
How does thrush present?
White patches on red, raw mucous membranes in throat/mouth
What is are some causes of thrush?
Post-antibiotics
Immunosuppressed patients
Smokers
Inhaled steroids
How is thrush treated?
Nystatin (1ml 4x daily for 7 days)
OR
Fluconazole (50mg/day for 7 days)
What is otitis media?
An upper respiratory infection involving the middle ear by extension of infection up the Eustachian tube.
Predominantly disease of infants and children
What are the most common bacteria that cause otitis media?
Hameophilus influenzae
Streptococcus pneumoniae
Streptococcus pyogens
How is otitis media diagnosed?
By swab of pus if eardrum perforates
What is the treatment for otitis media?
80% resolve in 4 days without antibiotics
First line - amoxicillin (5 days)
Second line - erythromycin (5 days)
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
Can become sore and painful
May be discharge or increased amounts of ear wax
Hearing can be affected if canal becomes blocked by swelling or secretions
What are some common bacterial causes of otitis externa?
Staphylococcus aureus
Proteus sp.
Pseudomonas aerguinosa
What are some 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 unrepsonsive/severe cases
Treat depending on culture results
- Topical clotrimazole (Canesten)
- Topical Nystatin
- Gentamicin 0.3% drops
What is malignant otitis?
An extension of otitis externa into the bone surrounding the ear canal
What are some symptoms of malignant otitis?
Pain and headache
What are signs of malignant otitis?
Granulation tissue at bone - cartilage junction of ear canal
Exposed bone in the ear canal
Facial nerve palsy (drooping face on the side of lesion)
Which investigations are done for malingnant otitis?
Plasma viscosity/CRP
Radiological imaging
Biopsy and culture to demonstrate the extent of the osteitis and its cause
What are some risk factors for malignant otitis?
Diabetes and radiotherapy to head and neck
What is acute sinusitis?
Mild discomfort over frontal or maxillary sinuses due to congestion seen in patients with upoer respiratory viral infections.
Severe pain and tenderness with purulent nasal discharge indicates secondary bacterial infection
What is the treatment of acute sinusitis?
Antibiotics for severe cases of > 10 days duration
First line - Phenoxymethylpencillin
Second line - Doxycycline ( NOT FOR USE IN CHILDREN!!!)
Which antibiotics are used in ear drops for a bacterial infection?
Neomycin
Gentamicin
Polymyxin B
Framycetin
Why are antibiotic ear drops not used in eczematous otitis externa?
They may cause local sensitivity.
Which types of ear drops should be used as wax solvents?
Sodium bicarbonate
Olive oil
Almond oil
What are some side effects of ear drops?
Dizziness
Local sensitivity
Ototoxicity
How can ear drops cause dizziness?
If the drops are not close to body temperature.
