Sepsis Flashcards
define colonisation
the presence of a microbe in the human body without an inflammatory response
Define infection
inflammation due to a microbe
Define bacteraemia
The presence of viable bacteria in the blood
Define sepsis
The dysregulated host response to infection
what are the main signs of septic shock
Persistent hypotension
Lactate greater than 2mmol/l
(despite adequate volume resuscitation)
Give some differentials of diffuse pain
Aortic aneurysm Aortic dissection gastroenteritis Early appendicitis Addisonian crisis Bowel obstruction DKA
Give some differentials of left upper quadrant abdo pain?
Gastric ulcer gastritis herpes zoster pulmonary embolism Pancreatitis
Give some differentials of right upper quadrant pain
appendicitis biliary colic cholecystitis herpes zoster hepatitis PE
Give some differentials of left lower quadrant pain
diverticulitis (sigmoid) ectopic pregnancy endometriosis ovarian cyst ovarian torsion testicular torsion PID
Give some differentials of right lower quadrant pain
appendicitis crohn's disease aortic aneurysm endometriosis ectopic pregnancy testicular/ovarian torsion meckel's diverticulum PID
what tests do you do to diagnose an infection
Microbiology - blood, stool, urine, wound/tissue culture, CSF, sputum
Serology
Antigen detection
PCR
What is the sepsis 6
Blood culture Urine output Fluid resuscitation - also give vasopressors (norepinephrine, vasopressin etc) Antibiotics IV Lactate levels Oxygen
what test do you do to identify whether it is strep or staph
Catalase
\+ve = staph -ve = strep
What test can you do to work out whether is is S.aureus or S. epidermis
coagulase
\+ve = S.aureus -ve = S.epidermis
what are the most common sources of infection in sepsis
Respiratory
Abdominal
UTI
Soft tissue, bone, joints
In what 3 ways can you classify a bacteria
Shape
- spirilla
- Bacilli
- Cocci
Gram stain
- Positive = purple
- negative = pink
Oxygen demand
- aerobic
- anaerobic
What is responsible for the gram staining dye remaining purple in positive organisms
Thick layer of peptidoglycan which traps the dye
Give some examples of gram positive bacteria
Cocci (aerobes) - staphlococcus - streptococcus - enterococcus (anaerobes) - peptostreptococcus
Rods (aerobes) - corynebacterium - listeria - lactobacillus - mycobacterium - bacillus (anaerobes) - clostridium
What type of bacteria are staph and strep classed as and how do you tell them apart?
Gram positive
Staph - clusters, wound infections
strep - chains, throat often
Give some examples of gram negative bacteria
Cocci
(aerobes)
- Neisseria
Rods (aerobes) - pseudomonas (anaerobes) - salmonella - shigella - Klebsiella - campylobacter
Spiral (aerobes) - leptospira (anaerobes) - borrelia - treponema
what are coliforms
E.coli and similar
Gram negative rods
What organism is most associated with UTI
E.coli
what organisms are most associated with diarrhoea
salmonella
shigella
E.coli
What organisms are most associated with lower resp. tract infections
klebsiella
enterobacter
What kind of antibiotics can be active towards gram negatives
Beta lactams - amoxicillin
aminoglycosides - gentamicin
macrolides - erythromycin, clarithromycin
tetracycline - doxycycline
what kind of bacteria is H.influenzae
gram negative coccobacillus
what are some atypical organisms causing of pneumonia and what antibiotic works against them
Mycoplasma pneumoniae
coxiella burnetti
Legionella,
chlamydophila psettaci
Doxycycline (main one)
(legionella doesn’t respond great to this)
macrolides
Main causes of gram negative sepsis
E.coli, klebsiella, enterobacter
Pseudomonas aeruginosa
neisseria gonorrhoea
what is the main concern when giving gentamicin
nephrotoxicity
In streptococcus what can be used to differentiate S. viridans, S.pneumoniae, group A?
A - haemolytic - S. viridans, S. pneumoniae
B - haemolytic (green) - group A
what is mean inhibitory concentration
concentration of the drug required to kill 99.9% of organisms in 18 - 24hrs
what class of drugs are penicillin, flucloxacillin, amoxicillin, piperacillin etc in?
Beta lactams
classification of streptococci on agar?
Beta haemolytic strep - complete lysis next to growth, clear zone 1. Group A beta - strep. pyogenes 2. Group B beta - strep agalactaiae Alpha haemolytic strep - partial haemolysis, greenish colour to blood agar Gamma haemolytic strep - non haemolytic
Pathology of community acquired pneumonia
Organism reaches lungs
Immune activation and infiltration
Fluid and cellular build up in alveoli leads to impaired gas exchange
What are the clinical signs of community acquired pneumonia
cough increased sputum chest pain dyspnoea fever chest xray with infiltrates
what are the most likely organism to cause community acquired pneumonia
strep pneumoniae
H. influenzae
Atypicals (legionella, psitacci etc.) and virus
staph aureus
what are the investigations for pneumonia
sputum culture
viral PCR
Antigen tests
biomarkers
what are some clinical signs of TB
Haemoptysis
night sweats
weight loss
what are some clinical signs of CMV?
visual changes
esophagitis
enteritis
encephalitis
what are some ways that a pathogen can evade being destroyed by immune responding cells
multiple mechanisms
camouflage the surface
Dampen the response
what is aspergillus
A lung infection caused by aspergillus, which is a type of mould that grows indoors and outdoors
what antibiotics target folate synthesis
sulfonamides
trimethoprim
what kind of antibiotic is gentamicin
gram negative
Antibiotics can be bactericidal or bacteriostatic, what does this mean?
Bactericidal - kill the bacteria directly
Bacteriostatic - supress the growth of bacteria
what is bioavailability
the proportion of a drug that enters the circulation when introduced to the body (i.e. the amount of the drug that has an active effect
A NEWS score of what should make you consider sepsis
> 5
what happens physilogically in septic shock
Capillary leakage
cytokine release
vasodilation
risk factors in sepsis
very young/very old
immunosuppressed
pregnancy
neonates
what is the empirical treatment for sepsis
Amoxicillin (vancomycin if penicillin allergic)
Gentamicin
metronizadole
what antibiotic would you give if C.diff was found on blood culture
Vancomycin
what does high lactate levels indicate?
Signs of hypoperfusion
(low BP)
>4 = bad, repeat at 4 - 6 hrs
what is minimum inhibitory concentration (MIC)?
the lowest concentration at which the antibiotic inhibits growth of the organism
If a patient is taking antibiotics what is the bacteria that they are at risk from?
C. difficile
what is flucloxacillin often used for
Staphylococcus skin infections
streptococcus skin infections
when should you not use urinalysis?
in those over 65
those with urinary catheters
will likely show bacteria that is not actually causing an infection
