309 - infections, immunological products and vaccines Flashcards
Which type of pathogen causes tuberculosis?
A bacterium causes tuberculosis.
What is the name of the bacterium that causes tuberculosis?
The bacterium which causes tuberculosis is called Mycobacterium tuberculosis.
What are the common symptoms of tuberculosis?
- cough (lasting 3 weeks or more) - might produce phlegm, may be bloody
- weight loss
- night sweats
- high temperature
- tiredness
- fatigue
- loss of appetite
- swelling of neck
How is tuberculosis spread?
Tuberculosis is spread by inhaling droplets.
Which area of the body does tuberculosis affect?
Tuberculosis usually affects the lungs (pulmonary TB) however other organs may be affected.
What is the treatment plan for tuberculosis
6 months: rifampicin + isoniazid
the first two months also - pyrazinamide + ethambutol
if TB is MDR, may need to take a longer course
Who is most at risk of contracting TB?
- from countries with high levels of TB
- prolonged close contact with infected
- living in crowded conditions
- compromised immune system (HIV, chemo, arthritis, Chrohns, diabetes)
- elderly
- poor health (homelessness, alcoholism, drug misuse)
What is the mode of action of rifampicin?
Rifampicin inhibits DNA dependent RNA polymerase leading to suppression of RNA synthesis & cell death.
What are the counselling points to consider for rifampicin?
- effectiveness of hormonal contraceptives (ie the pill) reduced so use alternative contraception (condoms)
- complete the course /take exactly as directed
- can discolour urine/tears/sweat (yellow through red)
- take on an empty stomach
- how to spot symptoms of liver disorder –> if get them seek immediate help
- if struggling to take medication as directed, speak to your TB team
What are the two strains of herpes called?
HSV-1 and HSV-2
What does HSV-1 cause?
HSV-1 causes oral herpes, however can be transmitted to genitals
What does HSV-2 cause?
HSV-2 is a sexually transmitted infection that causes genital herpes.
What type of pathogen causes herpes?
A virus causes herpes.
What is the name of the virus that causes herpes?
The herpes simplex virus causes herpes.
What are the common symptoms of oral herpes?
- cold sores
- fever
- muscle aches
What are the symptoms of genital herpes?
- small blisters that burst leaving open red sores around genitals/bottom/thighs/groin
- tingling/burning/itching genitals
- pain when urinating
- unusual discharge (women)
When is herpes most contagious?
Herpes is most contagious when a person is symptomatic.
How can genital herpes be spread?
- penetrative sex (PIV/anal)
- oral sex
- sharing sex toys
- via hands-genitals-mouths
What is the treatment for herpes?
Antivirals, such as aciclovir (or valaciclovir or famciclovir)
What is the mode of action of aciclovir?
Aciclovir is converted to aciclovir triphosphate in the body. The aciclovir triphosphate has a higher affinity for the viral DNA polymerase than the cellular DNA polymerase. Binds to the viral DNA polymerase causing chain termination so new viruses cannot be produced. Or binds to the viral DNA polymerase so strongly that other bases cannot associate with it, inactiviting it, preventing viral replication.
What are the counselling points for taking aciclovir?
- avoid sunlight if this causes a worsening of condition
- cold sores - don’t kiss whilst symptomatic
- genital herpes - use condoms + condoms on sex toys, advise that if sores are not covered by condoms then there is still a risk
- avoid sex whilst symptomatic
- space doses evenly
- complete the course of treatment
What type of pathogen causes thrush?
Thursh is caused by a yeast/fungus.
What are the symptoms for vaginal thrush?
- white discharge (like cottage cheese) not smelly
- itching and irritation around the vagina
- soreness and stinging during sex and when urinating
What are the symptoms of thrush in men?
- irritation burning and redness around the head of the penis and underneath the foreskin
- white discharge (cottage cheese)
- unpleasant smell
- difficulty retracting foreskin
What are the symptoms of oral thrush?
- white patches/plaques
- loss of taste
- red mouth
- cracks in corner of mouth
- painful burning sensation
- sore throat
What is the name of the pathogen that causes thrush?
Candida albicans causes thrush
What drug is used for oral thrush?
nystatin is used to treat oral thrush
What drug is used for vaginal thrush?
clotrimazole - pessaries and creams are used to treat vaginal thrush.
What are the side effects of clotrimazole?
Clotrimazole has no common side effects in the BNF, however Donna says ‘local irritation’.
What are the counselling points for nystatin?
- how to use pipette
- swirl around the mouth (hold in mouth) and swallow
- space doses evenly –> after food & mouthwash
- contains sugar
- complete the course
What is the mode of action of nystatin?
disrupts membranes of fungi and yeasts causing holes to appear.
What are the counselling points for clotrimazole?
- creams and pessaries may damage latex condoms + diaphragms - use alternative contraception
- if pregnant, do not use the applicator
What is the mode of action of clotrimazole?
Clotrimazole alters permeability of the fungal cell wall. Inhibits production of components of the fungal cell membrane.
What type of pathogen causes malaria?
Protozoa, protoctist, parasite
What is the name of the pathogen that causes malaria?
Plasmodium
What are the symptoms of malaria?
- high temperature (38ºC or above)
- hot and shivery
- headaches
- vomiting
- muscle pains
- diarrhoea
When do symptoms of malaria usually appear?
Between 7 - 18 days of becoming infected, but may take up to a year (or longe).r
What is the vector for the spread of malaria?
The female Anopheles mosquito.
How can the spread of malaria be prevented?
- mosquito nets
- covering arms and legs - particularly at dusk and at night when mosquitoes are more active
- avoid standing stagnant water
- wear insect repellent
What drug is used to treat malaria?
Malarone is one of the drugs used to treat malaria.
What is the mode of action of malarone?
Malarone interferes with two different pathways to disrupt replication of mucleic acid so cannot make proteins so cannot survive.
What are the counselling points when malarone is taken for treatment of malaria?
- complete the course
- take with or just after food
What are the counselling points when malarone is taken for malarial prophylaxis?
- take with or just after food
- complete the course - start 2 days before travelling to malarial area and take until 1 week after return home
- advice about stayinh safe/avoiding mosquitos
- any illness within a year of returning, seek medical advice
What are the general counselling points for antimicrobial medicines?
- complete the course
- take with(out) food
- space doses evenly
- penicillin allergy?
- how to mix suspension - if not already mixed
- shake the bottle
- discard remainder
- storage requirements + expiry date
What disease factors affect the choice of anti-infective agent?
- what type of pathogen (virus, bacteria)
- area of the body that is infected
- what kind of infections
- systemic?
- IV needed?
What drug factors affect the choice of anti-infective agent?
- broad or narrow spectrum (spectrum of action)
- form of the drug
- target organism
What patient factors affect the choice of anti-infective agent?
- age
- weight
- allergies
- gluten free / sugar free / lactose free
- method of administration
- site of infection
- sex - breastfeeding/pregnancy
- compliance
- comorbidities
- treatments already tried
- renal/liver impairment
- immunocompromisation
What makes immunity considered active?
If immunity is active, antigens are received into the body.
What makes immunity considered passive?
If immunity is passive, antibodies are received into the body.
What is natural active immunity?
Natural active immunity is from the body’s response to infection.
- the body manufactures its own antibodies
- memory cells are produced on first exposure
What is artificial active immunity?
- injecting or orally administering small amounts of an antigen into an individual
- this is vaccination
What are toxoids?
Toxoids are toxins produced by a bacteria.
What are examples of ‘killed organisms’ vaccines?
- influenza vaccine
What are examples of ‘live’ vaccines?
- rubella
- TB
- mumps
What is natural passive immunity?
- when antibodies cross from the mother’s placenta and enters the foetus
- also from breastmilk
What is artificial passive immunity?
- antibodies formed in one individual are injected into the blood of another individual
What are the types of vaccine?
- toxoid
- killed organisms
- live
What is injected in a toxoid vaccine?
- toxoids are toxins produced by the bacteria e.g tetanus. The toxins are detoxified, but the antigenic properties still remain the same
- therefore a toxoid vaccine will stimulate antibody production without the symptoms of the disease
What is a killed organisms vaccine?
- some dead viruses and bacteria are able to provoke a normal antibody response and are used for immunisation purposes
- killed by heat or chemicals
What is a live vaccine?
- contain attenuated organisms
- weakened so won’t cause the disease but will still produce a response
How long should vaccine fridge temperature records be kept for?
Vaccine fridge temperature records should be kept for 21 years.
Why should vaccine fridge temperature records be kept for so long?
Vaccine fridge temperature records are kept for so long in case of innactive vaccines.
Why should vaccines not be stockpiled?
Vaccines have a short expiry so should not be stockpiled.
What action should you take if vaccines are not stored correctly?
- quarantine them in the fridge
- alert supervisor - may need to reorder
- see SPS data - are they still ok? do they need a shorted expiry?
Why are vaccines stored in a box?
Vaccines are stored in a box because they are light sensitive.
What is the cold chain?
A cold chain is a temperature-controlled supply chain. An unbroken cold chain is an uninterrupted series of refrigerated production, storage and distribution activities, which maintain a desired low-temperature range.
