Diseases involving the immune system Flashcards
sepsis
SYSTEMIC INFLAMMATION
A condition
when the bodies response to infection causes injury to its own organs and tissues - caused by the cytokine storm
sepsis is manifested by two or more of the following condition
hyperthemri >38.3) or hypothermia (<35.5), tachycardia, tachypnea, high white blood cell count, immature neutrophils
hyperthermia
above 38.3 degrees
hypothermia
below 35.5 degrees
tachycardia
above 100 beats/min
tachypnea
above 20 breaths a min
white blood cell count
above 12,000/mm3 or below 4,000/mm
immature neturophils
below 10%
treatment for sepsis
- intravenous fluid- tackle low BP and tachycardia
- antibiotics (as soon as possible)
biomarkers of spesis
-procalcitoin
why does sepsis cause organ failure
cytokines such as TNF, il_1, iL-6 may activate pro coagulation
- causing endothelial damage
- increasing anti-fibrinolysis
- formation in small blood vessels will cause multiple organ failure
sepsis simple
defined as a systemic infection which is accompanied by an acute inflammatory response
most common sepsis is
bacterial
sepsis caused by gram negative bacteria
due to a response by the host to the lipid A (endotoxin) component of lipopolysaccharide found on the pathogen
Sepsis caused by gram positive bacteri
response to the cell wall lipoteichoic ci
bacterial exotoxins
act as super antigens also may cause sepsis- they bind MHC and T-cell receptors in the absence of antigen prevention- causes the forced released of cytokine by T-cells.
how are antibiotics administered
intramuscular (IM) or Intravenous (IV)
b-lactams
penicillin, cephalosporins, monobactams- work by interfering with synthesis of bacterial cell wall peptidoglycan
Benzylpenicillin
narrow spectrum but effective against Neisseria and Haemophilia spp
3rd generation cephalosporins
broad spectrum
sepsis and the cytokine storm
severity of infection is sure to an activation cascade that will lead to an auto amplifying cytokine production: the cytokine stomr- example of when the immune systems reaction can be fatak
cytokine
a broad category of a small protein, produced and released with the aim of cell signaling.
cytokine storm
due to positive feedback loop of cytokines
cytokines signal to immune cells such as
T cells and macrophages to travel to the site of infection
after arriving at the site of infection
they are stimulated by more cytokines- this reaction becomes uncontrolled and too many immune cells become activated in one place
example of how sepsis can affect the lungs
cause acute respiratory distress syndrome due to too many pro inflammatory cytokines:
- necrosis
- tissue destructioon
- influx of leukocytes
- dilation of blood vessels
fluids and immune cells may accumulate and block off the airways
meningitis
inflammation of the menininges and subarachnoid space
symptoms of meningitis
headaches, fevers, nuchal rigidity
nuchal rigidity
difficulty touching the chin to the chest with the mouth close
what is used to diagnose meningitis
CSF analysis
what can cause meningitis
-bacteria (meningitis neisseria), fun, protozoa and sometimes noninfectious conditions
which is the most serious meningitis
bacterial- most rapidly progressive
aseptic meningitis
sometimes used synonymously with viral meningitis- however refer to acute meningitis caused by anything other than the bacteria that typically cause acute bacterial meningitis. Can be caused by viruses, drugs, disorder or occasional other organisms like Lyme disease, Borrelia burgdorferi.
what procedure is carried out to test for meningitis
a lumbar puncture- findings tend to differ by the type of meningitis but can overlap
examples of viral meninigitis
herpes complex, mumps, HIV
examples of fungal meningitis
- Cryptococcus neoformans
- Candia albicans
- Aspergillus fumigatus
Bacterial causes of meningitis
S.aureus
E.coli
M.tb
how may the CSF look
cloudy or bloody due to WBC.
if neutrophils are present in the CSF the infection is most liekly
bacterial
if lymphocytes present
viral or TB
why is blood glucose lower in CSF during a bacterial infection
due to cells within the CSF metabolising glucose e..g bacteria, tumour, WBCs
normal CSF
- all lymphocytes are qual
- less than 40mg/d; of protein
- more than 50% of blood glucose
CSF for bacterial meningitis
- leukocytes greatly increased
- proteins elected
- less than 50% blood glucose
specific tests for bacterial meningitis
- gram staining yield is high if 10% colony forming unit of bacteria/mL
- bacterial culture
- PCR is available
CSF for viral men
- lymphocyes
- elevated proteins
- normal gluose
specific tests for viral men
=PCR to check for enteroviruses or herpes complex or west nile
CSF for fungal meningitis
- lymphocytes
- elevated
- less than 50% of blood glucose
specific test for fungal men
- crypotcoccal antigen test.
- fungal cult
- india ink
challenges of production of MenB
Men B this was the non-antigenic nature of some of the surface antigens as they resembled self-antigens.
gram positive
purple
gram negative
pink
Streptococcus pneumoniae
Gram positive (purple) diplococci
Hameophilus influenzae
gram negative (pink) rod or coccobacilli
Neisseria meningitis
gram negative (pink) diplococci
Listeria monocytogenes
gram positive (purple) rod shaped
