Case of the collapsed traveller Flashcards
gram positive colour and negative?
positive purple, negative pink
gram positive?
thick peptiodglycan layer hold onto purple dye
gram postive circular?
staphylcoccus
grampositive diplococci
streptococcus pneumoniae
gram negative rods or bacilli?
ecoli, escherichia
gram negative coccus?
neisseria gonorrhoea
streptococci species haemolysis on blood agar?
alpha- partial green
beta- complete so translucent
gamma- no haemolysis
e.coli 0157:H7 causes?
food poisoning
staphylcoccus aureus…?
commensal of nose 60%
s.aureus is special because?
coagulase positive
example of coagulase negative
staphycoccus epidermis
cellulitis cause
strep pyogenes, staph aureus
3 ways to classify streptocci?
- haemolysis
- lancefield groups- surface carbohydrate antigens
- true species name
which organisms cause alpha haemolysis?
viridans type streptococci, common comensals of mouth,
s.pneumoniae, s.milleri, s.mitis, s.sanguis
necrotising fasciitis?
s.pyogenes infection of deep tissues, producing tissue destructive enzymes in stationary phase
signs of necrotising fascitis?
pain out of proportion to physical signs
bruising and blistering
generalised toxaemia
renal impairment
high crp
raised CK
streptococcus pyogenes levels?
superficial- pharyngitis, cellulitis
deep- necrotising fascitis/ myoitis
autoimmune sequelae- rheumatic fever, glomerulonephritis
gram negative bacteria?
nesisseria meningitidis
n.meningitidis blebbing?
lipopolysaccharide shedding (endotoxin)
why are you likely to grow staph epidermis in someones blood?
someone didnt clean the skin before they took the blood
endpoint of sepsis
purpura fulminans (bruising that comes on like lightening)
concept of sepsis?
infection, host tries to contain and cures, dissemination can lead to cellular and organ damage
SIRS definition?
fever more than 38, less than 36
tachypnoea more than 20
tachycardia more than 90bpm
leucocytosis/leucopenia more than 12000 or less than 4000
more than 2 out of 4 required
proinflammatory cytokines cause?
increased vascular permeability and decreased vascular resistance
decreased cardiac contractility
fever diarrhoea, metabolic changes- insulin resistance(hyperglycaemic), protein catabolism
raised neutrophil, migration, adhesion, first high then low
increase coagulation
sepsis shock?
early distributive shock- warm peripheries, peripheral vasolidilation
hypovolaemic shock- cold peripheries
cardiogenic shock
LPS is recognised by?
TLR4, but can be macrophage scavenger receptor
other PAMPS?
lipopolypeptides, peptidoglycans, flagellin microbial DNA/RNA
other pattern recognition receptors?
CD15, TLRs1-11, NOD1/2, beta integrins
gram positive bacteria can cause sepsis through?
lipotechoic acid, peptidoglycans
superantigen exotoxins are released by?
staph aureus, streptococcus pyogenes- toxic shock syndrome
toxic shock syndrome result?
skin desquamation
superantigens cause?
huge t cell responses
organ dysfunction score?
SOFA- six organ symptoms
resp, coagulation, liver, cardiovascular, cns, kidney
initial antibiotic treatment of sepsis
initate treatment in 1 hour
iv antimicrobial from agreed local formulary
deadliest malaria parasite in africa?
p.falciparum
most dominant malaria parasite in sub saharan africa?
p.vivax
what is injected into bloodstream?
sporozoites
from liver stage what is released?
merozoite
what happens in red blood cell?
ring- trophozoitem schizont, which bursts and release merozoites which infect more rbcs
what is taken up by mosquito?
gametocytes
why is there no malaria in UK?
parasite multiplication affected by temp, less than 16 no replication
how can we control malaria?
insecticide treated nets
indoor residual spraying
malaria vaccination
treatment
prophylaxis
prompts diagnosis of malaria?
fever, visited malaria endemic area,
how do you test for malaria?
giema-stained blood film
rapid diagnostic tests
falciparum look like
ring trophozoite
what does microscopy tell you
species, parasitemia, parasite stage
presentation of malaria?
myalgia, headache, fever, abdominal pain, lethargy diarrhoea and vomiting
severe malaria?
parasitaemia more than 2%
or less than 2 but schizonts present or complications
how does malaria affect rbcs?
- malaria parasites inserts proteins PfEMP1 onto infected rbc surface
- form adhesive knobs which
how many var genes does malaria have?
60
how to treat malaria?
drug susceptibility
type of plasmodium
prophylaxis
how severe
iv quinine side effects?
arrhythmias,
hypoglycaemia
potentially lethal hypotension
treatment of severe malaria?
iv artesunate- kills circulating ring stage parasites as well as schizonts
hypnozoites living in liver are due to?
p.vivax, p.ovale
how to treat p.vivax and p.ovale?
primaquine
activated charcoal should be given?
1st hour
cocaine and amphetamine neutransmitters?
dopamine and noradrenaline
diagnostic tests for cocaine/results?
ECG tachyarrhythmia
metabolic acidosis
increased creatnine kinase
how to treat prolonged QRS?
iv sodium bicarbonate
morphine toxicity sign?
pinpoint pupils, accumulating co2, bradycardia
naloxone has?
short half life compared to the opiate you are giving it for
benzodiazepine antagonist- reversal
flumazenil- can give seizure
methylene blue
aspirin overdose?
metabolic acidosis and respiratory alkalosis
