IMMUNE 118 Pyrexial Illness Flashcards
What is the thermoregulatory centre in the body?
Hypothalamus
What is the main source of heat in the body?
The liver
What is the name for something that sets the body’s temperature at a higher point?
Pyrogens
What is the difference between Fever and Hyperthermia?
Fever is a regulated increase in body temperature whereas hyperthermia is not and can be damaging
Why is fever good?
Anti-pathogen, increased immune function also is a useful clinical sign
Why is fever bad?
Consumes energy - 1’C rise = 13% increase in metabolic rate
What are the 4 stages of fever?
Prodromal, chill, flush and defervescence
Describe the prodromal phase
Non specific: headache, fatigue, general malaise and aching
Describe the chill stage
Shaking/rigors, vasocontriction, piloerection and feeling cold
Describe the flush stage
Body temperature reaches new set level, being warm, flushed
Describe the defervescence stage
Sweating to reduce heat as fever falls
Name some body adaptations to inhibit bacterial colonisation
Skin - dry, regular turnover, commensals, antimicrobial
Mucous membranes - mucus, removed by cilia/peristalsis
Adherance - e.g. in urinary tract
How does a flagella help bacteria to colonise and invade?
Motility overcomes electrostatic forces & acts in receptor ligand binding
What is an invasome?
Like a fimbriae but thicker and longer - projection of the surface that allows firm attachment and is a prerequisite to invasion
What is a biofilm?
Where lots of bacterial cells stick together and adhere to the cell surface wall allowing decreased metabolism, minimal cell division (so less susceptible to Abx)
How might bacteria invade through epithelia?
by inducing changes in the cytoskeleton or forcibly through without
How might bacteria invade between the epithelial cells?
Paracytosis through the cell junctions
Post-epithelial invasion what 3 main ways can a bacteria disseminate throughout the body?
Using the circulatory system, by surviving inside phagocytes or by digesting through tissues
Name some inflammatory cytokines?
What do they do?
IL1, IL6, IL-12 and TNF-alpha
Act on hypothalamus to increase PGE2 synthesis
What is intermittent fever?
Temp returns to normal once every 24 hours
What is remittent fever?
temp does not return to normal but varies a few degrees either way
What is a sustained or continuous fever?
Temp stays high with minimal variation
What is a recurring or relapsing fever?
1 or more episodes lasting as long as several days with normal temperature in between
