infectious diseases Flashcards
feature gram positive bacteria
thick peptidoglycan cell wall
bacilli
rod
cocci
circular
gram positive cocci
staph
strep
enterococcus
gram positive rod
corneybacteria
mycobacteria
listeria
bacillus
nocardia
common gram negative bacteri
n.meningitidis
n.gonorrhoea
h.influenzae
e.coli
klebsiella
pseudomonas aeruginosa
moraxella cattarhali
gram positive anaerobes
clostridium
lactobacillus
actinonyces
propionibacterium
features atypical bacteria
cant be gram stained
often cause atypical pnuemonia
what is MRSA
staph aureus resistant to beta lactams
mx MRSA
doxycycline, clindamycin, vancomcin, teicoplanin, linezolid
e.g. extended spectrum beta lactamase bacterua
e.coli
klebsiella
mx extended spectrum beta lactamase bacterua
carbapanems (meropenem, imipenem)
abx that inhibit cell wall synthesis with a beta lactam ring
penicllin
carbapenems
cephalopsporins
abx that inhibit cell wall synthesis without a beta lactam ring
vancomycin
teicoplanin
abx that inhibit folic acid metabolism
sulfamethoxazole: blocks DHFA to THFA
trimethoprim: blocks THFA ro folic acid
mechanisms action abx
inhibit cell wall synthesis
inhibit folic acid metabolism
inhibit nucleic acid synthesis
inhibit protein synthesis
how does metronidazole work
inhibits nucleic acid synthesis in anaerobes
abx that inhibit protein synthesis by targeting ribosome
macrolides
clindamycin
tetracyclines
gent
chloramphenicol
penicillins
pen v
amoxicillin
fluclox
benpen
coamox
tazocin
what does pen v work against
beta haemolytic strep, strep pneumoniae, anaerobes
what does amoxicillin work against
beta haemolytioc strep
strep pnuemonia
enterococcus
anaerobes
what does fluclox work against
staph aureus
beta haem strep
anaerobes
what does benpen work against
beta haem strep
strep pnuemonia
enterococcus
n.meningitidis
what does co amox work against
staph aureus
beta haemolytic strep
strep pneumonia
enterococus
h.influenzae
e.coli
anaerobes
what does tazocin work against
staph aureus
beta haem strep
strep pneumonia
enterococcus
h.influenzae
e.coli
pseudomonas aueruginosa
moraxella catarrhalis
anaerobes
e.g. cephalosporin
ceftriaxone
what does ceftriaxone work against
staph aureus
beta haemolytic strep
strep pneumoniae
n.meningitidis
h.influenzae
e.coli
moraxella catarrhalis
e.g. carbapenems
meropenem
what does meropenem work against
staph aureus
beta haem strep
stre pnuemonae
enterococcus
n.meningitidis
h.influenzae
e.coli
ESBL
pseudomonas aeruginosa
moraxella catarrhalis
anaerobes
what does trimethoprim work against
e.coli
e.g. macrolides
erythromicin
clarithromycin
azithromycin
what does macrolides work against
staph aureus,
beta haem strep
strep pneumonia
atypicals
e.g. lincosamides
lindamycin
what does lindamycin work against
staph aureus
beta haem strep
strep pneumoniae
anaerobes
what does gentamicin work against
staph aureus
MRSA
e.coli
pseudomonas aeruginosa
moraxella catarrhalis
e.g. aminoglycoside
gentamicin
e.g. quinolones
ciprofloxacin
levofloxacin
what does ciprofoxacin work against
staph aureus
n.meningitidis
h.influenzae
pseudomonas aeruginosa
moraxella catarrhalis
atypicals
what does levofloxacin work against
staph aureus
n.meningitidis
h.influenzae
pseudomonas aeruginosa
moraxella catarrhalis
atypicals
strep pneumonia
e.g. glycopeptides
vanomycin
teicoplanin
what does vancomycin and teicoplanin work against
staph aureus
MRSA
beta haem strep
strep pnuemonia
enterococus
what does metronidazole work against
anaerobes
give e.g. tetracyclines
doxycycline
what does doxycycline work against
staph aureus
MRSA
strep pneumoniae
h.influenzae
moraxella catarrhalis
anaerobes
atypicals
what is sepsis
immune response to pathogens->cytokines->immune activation ->vasodilation
more permeable=oedema
activation coag syte ->thrombocytopenia and haemorrhage ->DIC
increased lactate due to anaerobic resp
features septic shock
BP<90
lactate >4
mx septic shock
fluids
inotropes (noradrenaline)
what is severe sepsis
organ dysfunction e.g. hypoxia, oliguria, AKI, thrombocytopaenia, coag, low BP high lactate
presentation sepsis
increased RR
confused
infection source
AF
temp
reduced urine output
mottled skin
mx sepsis
within 1 hr: blood lactate, blood cultures, urine output + oxygen, broad sepctrum abx, iV fluid
neutropenic sepsis
sepsis and neutrophils <1
when to suspect neutropenic sepsis
temp>38
mx neutropenic sepssi
abx e.g. tazocin
meds causing neutropenia
chemo
clozapine
hydroxychloroquine
methotrexatee
quinines
sulfasalazine
carbimazole
infliximab
rituximab
lowe UTI sx
dysuria
suprapubic pain
frequency
urgency
incontinence
confusion
sx pyelonephritis
fever
loin/back pain
N+V
redued appetite
haematuria
renal angle tenderness
ix UTI
dipstick: nitrities=bacteria, leukocytes=infection/inflammation
MSU culture
causes UTI
e.coli
klebsiella pneumoniae
enterococcus
mx simple UTI
trimethoprim or nitrofurantoin
F=3d, F abnormal anatomy=5-10d, M or catheter=7d
mx UTI in pregnancy
7d nitrofurantoin (not in 3rd T) or cefalexin
mx pyelonephritis
7-10d cefalexin, co-amox, trimethoprim, ciprofloxacin
features cellulitis
warm
erythema
oedematous
bullaie
causes cellulitis
staph aureus
group A strep (pyogenes)
group C strep (dysgalactiae)
MRSA
features staph aureus cellulitis
gold crust
class cellulitis
1=no systemic activity
2=systemic toxicity or comborbidity
3= significant systemic toxicity or comborbidity
4=sepsis
mx cellulitis
admit for IV if class 3/4
abx: fluclox. 2nd line=clarithromycin or co-amox
cause tonsilliti
viral
group A strep (pyogenes)
centor criteria
bacterial tonsiliits:
fever>/= 38
tonsillar exudate
no cough
lymphadenopathy
mx tonsilitis
centor score >/= 3 = 10d penicillin V
features otitis media
bulging red tympanic membrane
cause otitis media
viral
strep pyogenes
strep pneuminoae
mx otitis media
3-7d without abx or amoxicillin
2nd line: clarithromycin, co-amox
mx sinusitis
none
after 10d: 2w steroid nasal spray
if likely bacteria then penicillin V or clarithromycin
commob causes intra abdo infecion
anaerobes: bacteroids, Clostridium
e.coli
klebsiella
enteroccocus
strep
mx intra abdo infection
abx
oral if mild +/- stat gentamicin
co-amox or amox + gent + metronidazole or ciprofloxacin +metronidazole
mx spontaneous bacterial peritonitis
piperacillin + tazobactam
levofloxacin + metronidazole
septic arthritis sx
often knee
hot
red
reduced ROM
fever
sepsis
cause septic arthritis
staph aureus
neisseria gonorrhoea
mx septic arthritis
aspiraye and culture/gram staine
abx: IV fluclox and rifampicin for 3-6w
what s influenza
RNA virus
types influenza
A, B and x
A and B most common
ix influenza
nasal/throat swab
mx influenza
none
if high risk: oral oseltamivir or inhaled zanamivir within 48h
common viral causes gastroenteritis
rotavirus
norovirus
adenovirus
features e.coli gastroenteritis
faeces, salads, water
e.coli157: shiga toxin->bloody diarrhoea and vom
features salmonella gastroenteritis
raw eggs and poultry
sx start 12h-3d after: water diarrhoea
features campylobacter jejuni gastroenteritis
travellers: poultry, water, milk
after 2-5d: bloody diarrhoea, vom
give azithromycin
features shigella gastroenteritis
faeces
bloody diarrhoea after 1-2d
features bacillus cerus gastroenteritis
rice
vom after 5h, watery diarrhoea after 8h, resolves after 24h
features yersina enterocolitica gastroenteritis
pork
after 4-7d: watery/bloody diarrhoea. lymphadenopathy
often children
can last 3w
adults=mesenteric lymphadenitis
features staph aureus toxin gastroenteritis
eggs, dairy, meat
D+V within hours, resolves 1d
features giardiasos
parasite
faeco-oral
chronic diarrhoea
give metronidazole
mx gastroenteritis
culture stool
rehydration
avoid work for 48h after sx resolve
complications gastroenteritis
lactose intolerance
IBS
reactive arthritis
GBS
what is TB
acid fast bacili
stain for acid fast bacili
zeihl nellson
goes red
where can TB spread
extra-pulmonary: lymph nodes (cold abscess)
pleura
CNS
GI
GU
bones
miliary TB
disseminated and severe
presentation TB
lethargy
fever/night sweat
decreased wt
cough +/- haemoptysis
lymohadenipathy
erythema nodosum
ix TB
mantoux test
interferon gamma release assay
CXR
cultures and NAAT - sputum, blood, lymoh node
mantoux test
result >5mm = TB vaccination, latent or active TB
interferon gamma release assay TB
confirms latent
CXR findings TB
primary: patchy consolidation, pleural effusion, hilar lymohadenopathy
secondary: patchy or nodular consolidation with cavitation
miliary=millet seeds
mx latent TB
isoniazid or rifampicin for 3m or isoniazid 6m
mx active TB
rifampicin and isoniazid 6m
pyrazinamide and ethambutol 3m
SE rifampicin
red urine and reduced effect other drugs
SE isoniazid
peripheral neuropathy
need pyridoxine (vit B6) alongside
SE pyrazinamide
increased uric acid
SE ethambutol
colour blind
reduced visual acuity
TB vaccination
BCG vaccine for those at risk
what is HIV
RNA retrovirus
types 1 and 2
destroys CD4 TH cells
HIV progression
flu like illness
asx
immunocompromised and AIDs
AIDS defining illnesses
kaposis sarcoma
pneumocystis
jirovecci
pneumonia
CMV
candidiasis
lymphomas
TB
testing for HIV
Ab
PCR p24 Ag
PCR HIV RNA
monitoring HIV
CD4 count <200=AIDS
viral load
mx HIV
ART e.g. HAART=protease inhibitor, integrase inhibitor, nucleoside reverse transcriptase inhibitor, non-nucleosude reverse transcriptase inhibitor, transcriptase inhibitor, entry inhibitor
prophylactic co-trimoxazole for PCP
monitor: CVD, cervical smears,
vaccines (no live): flue, pneumococcal, hep A+B, tetanus, diphtheria, polio
HIV post exposure prophylaxis
start within 72h for 3w
truvada + raltegravir
HIV test after 3m
malaria cause
plasmodia (protozoan parasites)
spread through bite of female anopheles mosquito
types plasmodium in malaria
plasmodium falciparum = most sev
plasmodium vivax
plasmodium ovale
plasmodium malariae
life cycle malaria
infected blood sucked up by anopehles ->reproduces in mosquito producing sporozites ->bites new person ->sporozites to persons liver
then either lay dormant (in P.vivax and P.ovale) or mature into merozoites->enter RBC->rupture_>haemolytic anaemia
sx malariea
incubation 1-4w
fever
rigot
malaise
myalgia
headache
vom
pallor due to anaemia
hepatospenlomegaly
jaundice
ix malaria
blood film on 3 consecutive days
mx malaria
uncomplicated: oral riamet/malarone/quinine sulphate/doxycycline
complicated=IV artesunate, quinine dihydrochloride
malaria prophylaxis
spray (DEET)
nets
malarone: progvanil, atovoquone
mefloquine
doxycycline
falciparum complications
cerebral malaria
seizure
LOC
AKI
pulmonary oedema
DIC
haemolytic anaemia
multiorgan failure
fever and been to nigeria
malaria
typhoid
dengue fever
fever and been to india
typhoid fever
dengue fever
chikungunya
fever and been to brazil
dengue fever
chinungunya
scrub typhus
swimming in lakes i africa
schistosomiasis
where is typhoid fever common
south asia (india, pakistan bangladesh)
southern and eastern africa
e.g. viral haemorrhagic fever
lassa
ebola
marburg
which abx to avoid in EBV and why
amoxicillin and ampicillin - cause widespread rash
what to avoid after EBV infection and why
contact sports for 4 w - complication EBV is splenomegaly which can rupture and haemorrhage
Mild pneumonia and mx
Curb 0/1
Amoxicillin PO
Sev pneumonia and mx
Curb 3-5
IV co amox + PO clarithromycin
Definition HAP
Been in hospital over 48h
Or been admitted in past 30d
First line ix IE
3 sets blood cultures at 30 mins apart with at least 10ml blood (high vol) before abx)
Cause IE IVDU
Staph aureus
Cause IE hx prostatitis
Enterococcus faecalis
Cause IE immunocompromised
Candida
Cause IE prosthetic valve (early)
Staph epidermidis
Cause IE poor oral dentition
Strep mutans
Mx suspected meningitis while waiting LP
Assume bacterial unless confused
Ceftriaxone and dexamethasone
Add amoxicillin IV if over 60y to cover listeria
?Meningitis and normal CSF
IT IS NOT MENINGITIS
stop any abx if started
Abx if UTI/pyelonephritis and unwell
Iv co amox
If old = IV Piperacillin and tazobactam
Why is nitrofurantoin not good for pyelonephritis
Is concentrated in the urine
how does rifampicin effect contraception
reduced effectiveness COCP
what needs prescribing with isoniazid
pyridoxine (vit b6) to reduce peripheral neuropathy
which TBV tx can cause uric acid stones
pyrazinamide - increaes uric acid causing kidney stones and gout
how to test for legionnaires disease
urine antigen testing
mx legionnaiers pnuemoniae
clarithromycin
how can legionnaires pneumoniae present
SIADH
hyponatraemia