Microbiology Flashcards
List viruses that are common causes of oral ulceration
Herpes Simplex - type 1
Coxsackie virus - herpangia and hand, foot and mouth
Primary syphilis
What type of herpes simplex causes oral disease
Type 1
This type is acquired in childhood
How do you become infected by HSV1
Saliva contact
Describe primary gingivostomatitis caused by HSV1
Occurs in pre-school children
Ulcers and vesicles on the lips, buccal mucosa and hard palate
Systemic upset - fever, lymphadenopathy
Kids may struggle to eat
How can you treat primary gingivostomatitis caused by HSV1
Aciclovir treatment
May take up to 3 weeks to recover
Can herpes become latent?
YES
after primary infection it’s inactive form can stay in nerve cells and reactivate to re-infect the mucosal surfaces
What is the major complication of herpes infection
herpes simplex encephalitis (high mortality)
How do you diagnose HSV in the lab
Swab the lesion - may need to pop it to get fluid
Use viral swab with appropriate transport medium
PCR carried out to detect viral DNA
What is herpangia
You get vesicles/ulcers on the soft palate
Caused by coxsackie
Diagnosed by swab and PCR
Describe hand foot and mouth disease
Caused by coxsackie viruses
Get gingival stomatitis
Blisters on hand, feet and in the mouth (surprise, surprise)
Can be diagnosed by PCR but often not needed
Describe the presentation of a syphilis ulcer
Called a chancre Appears at the site of bacterium entry Thick and boggy ulcer Occurs in mouth or on genitals Sexually transmitted
What are apthous ulcers
Non-viral ulcers that are usually self limiting
Recurrent, painful ulcers that are confined to the mouth
Round/oval with inflammatory halo
Do not come with systemic disease
Which systemic diseases can cause recurrent, non-viral ulcers
IBD or coeliac Reiter's disease - arthritis Drug reactions Skin disease - pemphigus/goid Behcet's disease
Which age groups are commonly affected by acute throat infections
Children age 5-10
Young people 15-25
What are the most common causes of sore throat
Mostly viral or bacterial
Common cold, influenza and strep
Less common is HIV and diphtheria
If sore throat and lethargy persist into a second week, what is suspected
Infectious mononucleosis
Especially if aged 15-25
What causes infectious mononucleosis
Epstein-Barr virus
List some non-infectious causes of sore throat
Reflux
Smoking - chronic irritation
Hay fever
Physical irritation
What can a sore throat lead on to
Otitis media
Peri-tonsillar abscess
Para-pharyngeal abscess
Mastoiditis
At what point would a sore throat need referred
If throat cancer is suspected - persistent
Sore throat lasting 3-4 weeks
Dysphagia
Red, white patched or ulceration that lasts more than 3 weeks
Respiratory difficulty - emergency
What self-care advice should be given to patients with a sore throat
Regular analgesia
Medicated lozenges
Avoid hot drinks
Ensure good fluid intake
What is the most common cause of bacterial sore throat
Strep pyogenes
AKA Group A strep
How can you treat a strep pyogenes sore throat
Penicillin
What are some complications of strep pyogenes infection
Rheumatic fever
Glomerulonephritis
Describe the histological appearance of strep pyogenes
Gram positive
Cocci chains
Beta haemolysis - golden
List some of the CENTOR criteria for diagnosing a group A strep sore throat
Age under 15 Tonsillar exudate Tender anterior cervical lymph nodes History of fever Absence of cough
If scoring 3 or 4 should get antibiotics
List causes of neutropenia
Drugs - carbimazole Chemotherapy Leukaemia Aplastic anaemia HIV with low CD4 Immunosuppressants
List the clinical features of diphtheria
Severe sore throat
Grey/white membrane across pharynx
How do you treat diphtheria
Antitoxin
Supportive treatment
penicillin/erythromycin
What is infective mononucleosis also known as
Glandular fever
What are the symptoms of infective mononucleosis
Fever Enlarged lymph nodes Sore throat, pharyngitis, tonsillitis Malaise Lethargy - will last months Jaundice Rash Atypical lymphocytes Splenomegaly
List potential complications of infective mononucleosis
Anaemia
Thrombocytopenia
Treated with steroids
Splenic rupture - avoid sport for 6 weeks
Upper airway obstruction
Increased risk of lymphoma
EBV rarely causes infection in children - true or false
True
If infected in childhood you are usually asymptomatic
How do you treat infective mononucleosis
Bed rest
Paracetamol
Avoid sport
Steroids for some complications (rare as can make it worse)
How do you confirm EBV infection in the lab
EBV IgM Paul-Bunnel test Monospot test Blood count and film LFTs
How does a candida infection present
White patches on red, raw mucous membranes
When should you do further investigation for a candida infection
If recurrent
May indicate a T cell problem
How can you treat a candida infection
Nystatin or fluconazole
What is acute otitis media
An upper respiratory infection involving the middle ear by extension of infection up the Eustachian tube
Present with ear pain
Which bacteria are the most common causes of otitis media
Haemophilus influenza
Strep pneumoniae
Strep pyogenes
How do you treat a middle ear infection
Majority resolve in 4 days without antibiotics
Amoxicillin first line
Then erythromycin
What is malignant otitis externa
Infection of the outer ear that extends into the bone
Can be fatal
Get severe pain and headache
What are the clinical signs of otitis externa
Redness and swelling of the canal May be itchy Pain Discharge or increased ear wax Hearing can be affected
List bacterial causes of otitis externa
Staph aureus
Proeteus
Pseudomonas - swimmers
List fungal causes of otitis externa
Aspergillus niger
Candida albicans
Describe the presentation of acute sinusitis
Mild discomfort over frontal or maxillary sinuses due to congestion
Patient often has a URTI
Severe pain and tenderness with purulent discharge suggests bacterial infection
How do you treat sinusitis
Usually lasts 2.5 weeks
If case is severe or deteriorating and lasts more than 10 days, give antibiotics
Phenoxymethylpenicillin or doxycycline
What type of antibiotics would you give for otitis media and externa
Media needs oral
External uses topical (drops)
What virus causes glandular fever
EBV
What are the signs of glandular fever
Sore throat - red/inflamed Exudate on tonsils Cervical lymphadenopathy Tiredness Atypical lymphocytes
What is a common cause of swimmers ear?
Apergillus niger = black mould
Not picked up from water itself but the wet environment created by swimming makes it easier to grow
What type of infection is swimmer’s ear
otitis externa
Which criteria are used to determine the likelihood of a strep sore throat
Centor criteria
What are the rare complications of a strep sore throat
glomerulonephritis
rheumatic fever
What is the most common causative organism of bacterial tonsillitis
Strep pyogenes
