Infection & Immunology Flashcards
what is a pathogen
a disease producing microbe
what are most infectious diseases caused by
bacteria & viruses
what do all microbes have that distinguishes them
a cell wall
what is an example of a gram + microbe
staph
what is an example of a gram - microbe
e.coli
what is unique about viruses
they can’t exist on their own and have to be inside living cells
can have DNA or RNA
what is a broad spectrum antibiotic for
both +ve and -ve grams
what other microbes can occur from pre-existing conditions
fungi in patients undergoing chemo because it knocks out the normal microbiome in a person. they don’t normall cause disease but they have the potential to overgrow once the other parts of gut flora have been wiped
protoza not typically infections unless there is an immunosuppressant
prions rare but cause mad cow
where are non infectious microbes usually present in the body & what is their role
skin, vagina, oral cavity, GIT
- supporting immunity
- production of vitamins & other chemicals e.g. vitamin K
- protecting overgrowth of pathogenic microbes
why does a change in location lead to sickness sometimes
different microbes based on location, so it takes the body a while to get used to it
what can set back normal flora development during infancy
antibiotics
what is endogenous infection
infectious agents come from a person’s own microbiome
what is congenital infection
infectious agents passed from mother to child at birth or during pregnancy
what is exogenous infection
infectious agents from a source external to the patient resulting in cross infection
where do the majority of infections come from
exogenous
what are the stages of infectious disease
incubation - very mild, can be missed
prodromal - symptoms, illness
acute illness - can take medication or have medical intervention
convalescence - influenza takes weeks e.g. chronic carrier who is always producing, hep b
what carriers are most dangerous
chronic, asymptomatic, convalescent, passive (healthcare workers)
what is the difference between droplets and airborne
droplets are heavier
what is the lymphatic system
a circulatory system returns fluid pushed out of the capillaries to venous circulation
where are lymphs located
along blood vessels
do lymphs contain red blood cells
no
what are B cells
cells in blood or body fluid
what are T cells
cells that tend to be located in the spleen and thymus
do we have lymphoid tissue in our airways
yes
where do B & T cells originate from
bone marrow
what are primary lymphoid organs
bone marrow - where B & T cells are produced
thymus - where they mature
what are the secondary lymphoid organs
spleen & tonsils, where the cells sit and wait
what does the right lymphatic duct drain
hardly anything :)
only drains above the diaphragm on the right side
what does the spleen do during immune response
can expand, gets rid of red blood cells in the blood, stores red blood cells, does haematopoiesis
where is the spleen (rib numbers)
9-11th ribs
what happens if the spleen is removed
increases risk of infection, otherwise ok
what is asplenia
congenital absence of splenic tissue or it’s iatrogenic or it’s just not functioning (tumours/vascualr disease)
how does liver cirrhosis affect the spleen
causes issues with drainage in the splenic vein and portal vein because it can’t go to the liver, and can result in esophageal varices
what body injury can indicate a ruptured spleen
fracture of left lower rib
lymphadenopathy causes & definition
swollen lymphs
neoplasia - tumours that lodge in a lymph via lymphatic drainage from another site
lymph infection
drugs
reaction to immune responses
does pathology always increase the size of the lymph
not really, it can make it harder
what is lymphoedema, affects and causes?
accumulation of fluid in tissue from impaired lymphatic drainage
causes inflammation, hypertrophy of adipose tissue (chronic) & fibrosis
caused by primary - hereditary or congenital
secondary - trauma that damages lymph drainage, cancer, surgery
primary functions of lymphatic system
- return of excess interstitial fluid to blood
- transportation of fat & fat soluble vitamins via lacteals because we can’t digest lipids the same way we digest proteins and carbs directly across the abdominal wall. it has to be emulsified by bile
- body system responsible for immune responses
what are the 3 lines of defence
natural - skin, tears, eyelids, vomit, defecation
innate - immunity, inflammation
acquired - lymphocytes & antibodies
what are neutrophils
the first phagocytes involved in immune response
end up as pus
what are macrophages
sustained
activate other immune cells
what are signs of inflammation (acute)
heat
redness
oedema
pain
loss of function
what innate
something you’re born with
do inflammatory responses damage tissue
yes, but it can also heal
what factors affect healing
type of tissue
extent of damage
duration of inflammation
others
what is the diff between chronic and acute inflammation
chronic has an ongoing stimulus
how is inflammation visualised
size
fat - fluid in fat indicated on ct
what should specific immunity work against
specific foreign antigens
what is humoural immunity
production of antibodies
what is cell mediated immunity
production of effector cells in response to viruses, tumours etc
they activate T cells
what do NK cells target
virus infected and cancer cells
what do plasma cells do
produce antibodies
what immunity is associated with B-lymphocytes
humoural in response to antigens from bacteria, free viruses etc
what does a complement do
cell lysis - produces holes in cells
what are the different types of T cells
killer, helper, suppressor
what do memory B & T cells lead to
active & passive immunity
what is IgM
acute phase antibody (always there first)
what is IgG
secondary immune response (the memory antibody)
significant post vaccine etc
are T& B cells acquired immunity
yes
are antibodies and cytokines acquired immunity
yes
what is hypersensitivity
an over or altered reaction of the immune system
what are the types of hypersensitivity & their occurence & examples
immediate, cytotoxic & immune complex, delayed
type I, type II, type III, type IV
few min, few hours, after a few hours, after 24hrs, within 72
anaphylaxis, incompatible blood transfusion, rheumatoid arthritis, mantoux test for TB
what leads to anaphylaxis
spread of allergen, produce large amounts of IgE, oedema, blood vessels become leaky
medical emergency
how is anaphylaxis treated
adrenaline/ epipen
what are contrast allergies and are they common and what increases the risk and waht are the reactions
not common, within 20min
severe, life threatening, idiosyncratic, anaphylactoid reaction from contrast media
- same effects as anaphylaxis but not the same because it doesn’t produce IgE
- don’t require prev exposure
increased risk:
- age
- asthma
- dehydration
- prev history
reactions:
- hives
- itching
- runny nose
- life threatening arrythmia
- hypotension
- oedema
- seizures
- death
what are non-idiosyncratic reactions to contrast media
more common and predictable
- warm metallic taste in the mouth
- arrhythmia
- 30min - 7 days
what is autoimmunity & it’s causes
unresponsiveness of immune system or immune dysregulation
combination of environment, immune system, genetics
- viral infections, drugs, genetic
can autoimmune diseases be localised or systemic
both
are autoimmune diseases rheumatological (joints) or vascular
both
what diseases are localised autoimmune
addison’s disease
coeliac disease
crohn’s
diabetes type 1a
grave’s
multiple sclerosis
ulcerative colitis
what diseases are systemic autoimmune
lupus
rheumatoid arthritis
dermatomyositis
scleroderma
what is immunodeficiency
primary - one or more components of immune system missing as a congenital condition e.g. antibodies, T cells, B cells
secondary - acquired e.g. malnutrition means you don’t have all the components to produce antibodies, genetic diseases like diabetes, immunosuppressants, surgery, trauma, burns
