MedEd Micro 1 Flashcards
50M 6/12 Hx of weight loss and haemoptysis. Gold standard test for Dx?
sputum culture
why give b6 in TB Tx?
protect against side effects of isoniazid
stages of TB infection
primary - mycobacterium tuberculosis initial infection, often in childhood. no Sx
latent - suppressed, hanging around in foci, no Sx
post primary / secondary - reactivation of latent, often due to immunosuppression. Sx!!
causes of reactivation of TB
HIV infection
started on monoclonal ABs / immunosuppression
illness
3 stages of TB on a CXR
ball of macrophages = ghon foci
+ lympahdenopathy = ghon complex
+ calcification = ranki complex
PC of active TB (4)
weight loss / fever / night sweats / loss of appetite / fatigue
pulmonary - haemoptysis
lymphadenopathy
erythema nodosum
less common PC of active TB
miliary TB
meningeal TB
Pott’s disease
GUM TB
serosal / GI / adrenal / cutaneous
what is miliary TB
TB lesion erodes into BV and spreads all over body
how does meningeal TB present, in whom & what complication
subacute meningitic sx
HIV pts
++++ morbidity
what is pott’s disease and how does it present
TB in vertebrae
back pain / compression fracture / focal neurology
incidental result of GUM TB and why
sterile pyuria !! UTI Sx with nothing grown on MCS (bcos they don’t look for TB)
how does miliary TB look on CXR
lots of little white dots all over CXR (also all over rest of body but not as easy to see)
name pathognomonic cutaenous presentation of TB
lupus vulgaris
gold standard Ix for active TB with medium used
sputum culture, on Lowenstein-Jensen media
** buzzword **
what Ix is done for active TB in practice
sputum smear and Ziehl Neelson stain for acid fast bacilli
** buzzword **
why isnt sputum culture done for TB Dx in practice
takes too long to culture TB
another stain for acid fast bacilli
auramine rhodamine stain
(stains red / yellow)
** buzzword **
how is latent TB diagnosed
mantoux test
interferon gamma release assay (ellaspot)
difference between mantoux test and IFGRA for TB
mantoux - tests positive if you’ve had BCG vaccine OR you have latent TB, cheap
IFGRA - only positive if you have latent TB, expensive
5 drugs for TB Tx
RIPE
rifampicin
isoniazid + pyridoxine
pyrazinamide
ethambutol
duration of Tx for TB
all 4 RIPE drugs for 2 months,
then just 2 for 4 months (rifampicin and isoniazid)
what is pyridoxine and why is it given with RIPE
vitamin b6
isoniazid causes peripheral neuropathy due to depletion of b6
drugs used for drug resistant TB
aminoglycosides
fluroquinolones
new drugs
specifics - streptomycin / amicacin
Mx of latent TB
just rifampicin and isoniazid (less intensive regime)
2nd most common mycobacterium
leprosy (mycobacterium leprae / lepromatosis)
PC of mycobacterium leprae / lepromatosis
(2 Sx, buzzword finding, Hx finding)
skin changes - hypo/hyperpigmented lesions
peripheral nerve disease
*thickening of nerves ** buzzword
+ travel Hx / exposure
name other mycobacterium
mycobacterium leprae / lepromatosis
MAC - mycobacterium avium complex
mycobacterium marinum
mycobacterium ulcerans
who gets MAC
preexisting lung disease / HIV
PC of MAC
same as pulmonary TB
slow PC,
FLAWS / cough
PC buzzwords for mycobacterium marinum
“fish tank granuloma”
exposure to swimming pools / fish tanks
skin disease
what does mycobacterium ulcerans cause
buruli ulcer
PC of buruli ulcer
been in the tropics
painless, destructive ulcer
23F 2/52 dry cough, fever, myalgia.
O/E rash, jaundice
CXR bilateral consolidation
Organism?
mycoplasma pneumonie
what does LRTI encompass
bronchitis
pneumonia
abscess
empyema
describe bronchitis - who gets it / Mx and why / CXR
smokers / kids
don’t tend to get that unwell, so don’t usually treat unless supportive
CXR no changes
describe pneumonia - progression / CXR
look sick
treat with ABx
CXR shows consolidation
what is an abscess
puss filled cavitating lesion within lung parenchyma
2 key PC of abscess
FLAWS - esp swinging fevers !
Hx pneumonia - esp pneumonia not responding to ABx = abscess
MX of abscess
drainage
ABx alone not enough
what is an empyema
infection within an existing space in lung (ie the pleura)
3 classifications of pneumonia with definitions
CAPs - develop in community
HAPs - develop >48hrs after hospital admission
VAPs - develop in patients on ventilators
CXR of bronchitis
nothing
thickening of central bronchi
CXR of abscess
well circumscribed lesion with patchy airspaces within (cavity with fluid in)
what does CXR of empyema look similar to
pleural effusion - loss of costophrenic angle with meniscus
why are typicals / atypicals called that
typicals all present the same in classic pneumonia fashion
atypicals present weirdly
–> nothing to do with how common they are !!
describe typical pneumonia PC
systemically unwell
productive cough, fever, etc
lobar consolidation on CXR
what Mx do typical pneumonias respond to
penecillins
how do atypical pneumonias present
flu like prodrome
dry cough rather than productive
extra pulmonary manifestations
how does the Mx of atypicals differ from typical pneumonia
atypicals respond to macrolides, not penecillins like typicals
3 buzzwords for strep pneumoniae (Sx, unique Ix, path)
rusty coloured sputum
gram positive diploccoci
positive urine antigen test
buzzwords for h.influenzae (path, at risk)
COPD
gram neg coccobacillus
buzzwords for moraxella catarrhalis (path, at risk)
smokers
gram negative coccus
most common pneumonia bug
strep pneumoniae
3 buzzwords for staph aureus pneumonia (RFs, CXR lesion, path)
post-influenza pneumonia
cavitating lesions - cavity
gram positive cocci (grape like bunch)
4 buzzwords for klebsiella pneumoniae (RFs, CXR lesion, Sx, path)
alcoholics !! / post aspiration eg stroke
haemoptysis
cavitating lesions
gram negative rods
who gets chlamydia pneumoniae and how sick are they
asthmatics
not very sick
(less important)
3 buzzwords for legionella pneumophilia (RFs, Sx, Ix)
air conditioning - plumbers / travellers
very unwell - hepatitis, low Na, lymphopaenia
+ urine antigen test
pt has positive urine antigen test with pneumonia. what bugs?
strep pneumonia
legionella
3 buzzwords for mycoplasma pneumoniae (RFs, 2 buzzword signs)
young people in close proximity - halls etc
cold AIHA !! (jaundiced)
erythema multiforme !! (target lesions)
2 buzzwords for chlamydia psittaci (RFs, complication)
own exotic birds !!
culture negative endocarditis
2 buzzwords for coxiella burnetti (RFs, complication)
farm animals !!
culture negative endocarditis
what LRTIs can HIV+ patients get
PCP
TB
cryptococcus neoformans
nocardia
how does PCP classically present
dry cough
** desaturation on exertion >10%** buzzword
LRTIs in splenectomy pts
encapsulated organisms
- haemophilus
- strep
LRTIs in CF
pseudomonas aeruginosa
burkolderia cepacia
why is burkholderia cepacia important to know about in CF kids
contraindication to lung transplant
what LRTI bugs are people taking monoclonal ABs at risk of
TB reactivation
what LRTI bug do people with neutropaenia / asthma get
aspergillus
CXR of PCP
relatively normal
bat wing shadowing around the hilar
CT of PCP
honeycombing - big open spaces
ground glass shadowing
CURB 65 criteria
confusion - AMTS <9
urea >7
RR >30
BP <90/60
65 or older
What does a CURB 65 score of 0-1/2/3-5 mean
curb65 0-1 = treat at home, PO amoxicillin
curb65 2 = admit, co-amoxicillin and clarithromycin
curb65 3-5 = admit, co-amoxicillin and clarithromycin, consider ICU
standard tx of CAP
amoxicillin / co-amoxicillin / clarithromycin
- some combo of this
Tx of HAP
(1st / severe)
LOCAL TRUST GUIDELINES
usually 1st = ciprofloxacin and vancomycin
severe = piperacillin / tazobactam and vancomycin
what are you covering for in HAP
MRSA
pseudomonas
go to ABx for pseudomonas
piperacillin and tazobactam (tazocin)
go to ABx for MRSA
vancomycin
ABx for aspiration pneumonia
usually aspiration is a pneumonitis not pneumonia (ie chemical acid damage to lung, not infection) so not usually needed
go to ABx for anaerobic cover
metronidazole
clindamycin
indications for starting ABx for anaerobic cover
MUST be an indication not just if they’ve aspirated
- culture
- empyema / abscess
3 classifications of infective endocarditis
subacute
acute
prosthetic
PC of subacute endocarditis
indolent presentation
fever of unknown origin
FLAWS
new regurgitant heart murmur
splinter haemorrhages / janeway lesions
septic emboli - brain / spleen / kidney
immune phenomena - roth spots / osler nodes / glomerulonephritis
BUZZWORDS
PC of acute endocarditis
rapid onset
VERY septic / unwell
who gets prosthetic endocarditis and when
valve replacement pts (1-2 months post op)
location of IE usually
most ppl - left side as higher pressure
IVDU - tricuspid / right sides
osler nodes vs janeway lesions
oslernodes = painful
janeway lesions = painless
where do roth spots occur
retina
common organisms causing IE
strep viridans
staph aureus
most common organism in UK vs world causing IE
UK = staph aureus
world = strep viridans
organism causing IE within 2 months of valve replacement
staph epidermidis
organism causing IE in colon tumours
strep bovis
organisms causing culture negative IE
HACEK organisms
organism causing IE in bird keeper
chlamydia psittaci
organism causing IE in farmer
coxiella burnetti
organism causing IE in someone who’s had unpasteurised dairy
brucella spp.
what criteria is used to diagnose IE
Dukes
major criteria for Dukes IE
blood cultures positive for IE - 2+ culture of a bug associated with IE
evidence of endocardial involvement - scan showing vegetations
minor criteria for Dukes IE
predisposing factor - IVDU / heart condition
fever >38
vascular phenomena - emboli / infarcts / ICH / janeway lesions
immunological phenomena - osler nodes / roth spots / RF+ / GN
microbiological evidence - culture that doesn’t meet major criteria
how is IE diagnosed with Dukes
definite = 2 major OR 1 major + 3 minor OR all 5 minor
possible = 1 major + 1 minor OR 3 minor
Tx of IE
long course of ABx
- empirical / broad unless known organisms
- includes gentamicin
+/- surgery if indicated
indications for surgery in IE
continuing to worsen on ABx
acute heart failure
aortic root abscess
prosthetic valve
how is IE abscess development picked up on ECG
prolonged PR
what is non infective endocarditis
endocardial vegatations without infection
2 causes of non infective endocarditis
mucin producing adenocarcinomas - pancreatic especially
SLE / ALPS - Libman Sacks endocarditis
3 groups of presentations of GI infections
secretory - normal Sx
inflammatory - bloody diarrhoea
systemic sx
what Tx is not really used in GI infections and why
ABx - usually not bacterial, but protazoa
NB - exception is c.diff / very high risk and unwell
if an ABx is indicated in GI infection, which one is usually given
ciprafloxacin
organisms causing a secretory diarrhoea
bacillus cereus
staph aureus
e.coli
cholera
buzzword for bacillus cereus GI infection
reheated rice
buzzword for staph aureus GI infection
BBQs !!
short incubation - damage due to preformed toxins
buzzword for e.coli GI infection
traveller’s diarrhoea
NB - usually none bloody, only 1 specific type is bloody
2 buzzwords for vibrio cholera GI infection (sx and path)
ricewater stool
comma shaped bacteria
causes of blood diarrhoea
CHESS
campylobacter jejuni
haemorrhagic e coli
entamoeba histolytica
salmonella enterides
shigella spp
AND yersinia enterocolitica !!
buzzword for salmonella enterides
poultry / eggs
does salmonella typhi cause bloody diarrhoea
NO - causes typhoid which is constipation
how does yersinia present
bloody or non bloody diarrhoea
terminal ileitis / adenitis –> similar to appendicitis
protazoal GI infections
entamoeba histolytica
giardia lamblia
cryptosporidium / micosporidium spp
PC of entamoeba histolytica
bloody diarrhoea / chronic diarrhoea
liver abscess
histology of entamoeba histolytica
flask shaped ulcer
anchovy paste in abscess
buzzwords
tx of entamoeba histolytica
metronidazole
PC of giardia lamblia
chronic diarrhoea
malabsorption
- like coealic !
histology of giardia lamblia
pear shaped trophozoites
buzzword
tx of giardia lamblia
metronidazole
buzzword / who gets cryptosporidium or microsporidium diarrhoea
HIV+ patients
who gets c.diff diarrhoea
post ABx
which ABx cause c.diff diarrhoea
cephalosporins, clindamycin, ciprofloxacin
Ix for c.diff
stool c.difficile toxin
visualise pseudomembrane - looks like wet cornflakes
Tx of c.diff
- 1st infection
- 1st recurrence
- further recurrence
- fulminant infection
1st = oral vancomycin
recurr = oral fidaxomicin
mutliple recurr = faecal microbiota transplant
fulminant = oral vancomycin + IV metronidazole +/- surgery
(Meeran says 1st line is metronidazole tho)
27F with dysuria, smelly urine.
Urine dip shows leucocytes but no nitrites.
why?
UTI causes by staph aureus
what is a complicated UTI
UT abnormality
pregnant
immunocompromised
instrumentation
what is lower UTI vs pyelonephritis vs pyonephrosis
lower UTI / cystitis = only affects bladder
pyelonephritis = infection to kidneys
pyelonephrosis = pyelonephritis + obstruction
Mx of pyelonephritis vs pyonephrosis
nephrosis needs a surgical intervention to drain fluid / fix blockage
Ix UTI
urine dip
MC&S
renal tract imagine - USS or CT
what do nitrites signify on urine dip
coliform UTI - whether an enzyme is present
–> e.coli mainly makes the enzyme, so nitrites indicate e.coli UTI
diagnostic value for any UTI on MC&S
> 10^4 colony forming units/ml of any organism
diagnostic value for e.coli / staph saprophyticus UTI on MC&S
> 10^3 colony forming units/ml
MC&S features that show contaminated sample
epithelial / squamous cells
staph aurues (doesn’t cause UTI, on skin)
mixed growth
who are the only group in whom you’d treat asymptomatic UTI
pregnant women
most common cause of UTI
e.coli
most common cause of UTI in young women
staph saprophyticus
2 organisms in UTI that would indicate renal tract abnormalities
proteus mirabilis
klebsiella
buzzword for proteus mirabilis
struvite stones ** key
alkaline urine
what organism causes sterile pyruia
TB ** key
STIs - chlamydia
Tx of lower UTI
nitrofurantoin
trimethoprim
cephalexin
Tx course of lower UTI in complicated / uncomplicated
uncomplicated = 3d
complicated in male = 7d
when can you not give trimpethoprim / nitrofurantoin
can’t give trimethoprim in 1st trimester
can’t give nitrofurantoin in 3rd trimester
drug interaction of trimethoprim
methotrexate (folate antagonist)
Tx for pyelonephritis
admit pt
IV co-amoxiclav + gentamicin
organisms that cause surgical site infections, from most to least common
staph aureus
e.coli
strep spp.
pseudomonas
**EMQ Q
organisms that cause osteomyelitis or septic arthritis from most to least common
staph aureus
strep spp.
e.coli
** EMQ Q
organism that causes osteomyelitis or septic arthritis in sickle cell disease
salmonella
organisms that cause prosthetic joint infection from most to least common
staph epidermidis
staph aureus
strep spp.
e.coli
** EMQ Q
when is staph epidermidis the most common organism to cause prosthetic joint infection
ONLY IN FIRST 2 MONTHS POST OP
- after that, its staph aureus –> strep –> e.coli
34M 2/7 fever and menigism.
LP - clear, lymphocytosis, high protein / glucose
Dx?
viral meningitis
sites of CNS infection
meningitis - bacterial / viral / fungal
encephalitis - usually viral
brain abscess - infective collection in parenchyma
what can cause meningism that isn’t meningitis
SAH
causes of bacterial meningitis in neonates
GBS
listeria monocytogenes
e.coli
causes of bacterial meningitis in adults
neisseria meningitides
strep pneumoniae
causes of bacterial meningitis in elderly
GBS
listeria monocytogenes
adult ones too
causes of bacterial meningitis in immunocompromised ppl
TB
viral causes of mengitis
enteroviruses
HSV2
HIV seroconversion can present with meningitis
fungal causes of menigitis in HIV / immunocompetent
cryptococcus neoformans in HIV
cryptococcus gattii in immunocompetent
why can LP in raised ICP be a problem
raised ICP due to SOL –> worried about coning
indications for CT before LP
(rule out SOL)
focal neurology
seizures
reduced GCS
papilloedema
when should LP be done ideally
before ABx but don’t hold ABx off for this
buzzword for cryptococcus stain in LP
india ink stain
Ix in CSF analysis for ?meningitis
biochemical analysis
gram stain for bacteria
PCR viruses
Ziehl Neelson stain for TB
india ink stain for cryptococcus
CSF in viral meningitis
- colour
- WCC
- predominant WC
- protein
- glucose (CSF:blood)
- opening CSF pressure
clear
slightly high
lymphocytes
normal / slightly high
normal
normal / slightly high
CSF in bacterial meningitis
- colour
- WCC
- predominant WC
- protein
- glucose (CSF:blood)
- opening CSF pressure
cloudy / turbid
very high
neutrophils
very high
low
high
CSF in fungal meningitis
- colour
- WCC
- predominant WC
- protein
- glucose (CSF:blood)
- opening CSF pressure
fibrin web
normal / slightly high
lymphocytes
normal / slightly high
normal / slightly low
high / very high
CSF in TB meningitis
- colour
- WCC
- predominant WC
- protein
- glucose (CSF:blood)
- opening CSF pressure
cloudy and viscous
slightly high
lymphocytes
very high
very low
high
Tx of meningitis in GP
IM benzylpenecillin
999
Tx of meningitis in hospital
empirical IV ceftriaxone / cefotaxime
+ ampicillin if <3 months / >55y/o
2 other medications that can be added to meningitis ABx and why
dexamethasone if strep / h.influenzae
aciclovir if encephalitis can’t be excluded
most common HHV cause of encephalitis
HSV1
who gets arbovirus encephalitis
travellers - no 1 cause worldwide
unvaccinated. measles as a child, now 10 years later has encephalitis. Dx?
(** measles = buzzword)
SSPE
subacute sclerosing panencephalitis
HIV + on monoclonal treatment, now has encephalitis. cause?
JC virus
** buzzword with HIV
what syndrome does JC virus cause
PML - progressive multifocal leucoencephalopathy
**buzzword with HIV
Tx of encephalitis
empirically treat with aciclovir
Ix for encephalitis
MRI
LP / CSF PCR
what kind of growth pattern is seen in brain abscess
mixed growth !! strep / staph + anaerobes
pt with HIV and brain abscess. Dx?
toxoplasmosis
** buzzword with HIV
Ix and result of brain abscess
MRI > CT
ring enhancing lesion
Mx of brain abscess
ABx - wide spectrum and anaerobic cover
surgical drainage
+/- steroids +/- anti seizures
23M Hx of STIs. PC fevers, pustular rash, red swollen knee and wrist. Organism?
neisseria gonorrhoea
most common STI
chlamydia
5 different PCs of chlamydia
often asymptomatic
STI Sx - pain passing urine, discharge change, PID
reactive arthritis
serovars L1-3 –> lymphogranuloma venereum
opthalmia neonatorum, 1-2wks of life
PC of lymphogranuloma venereum
proctitis
obviously, painful inguinal lymph nodes
who gets lymphogranuloma venereum
MSM
what is opthalmia neonatorum
neonatal conjunctivitis
ix of chalmydia
NAAT
NOT culture
tx of chlamydia
doxycycline >azithromycin
reactive arthritis features of chlamydia
keratoderma blenorrhagica (brown rash)
balanitis
4 different PCs of gonorrhoea
asymptomatic
STI Sx –> PID
disseminated gonococcal infection
opthalmia neonatorum
PC of disseminated gonoccoal infection
fever
migratory arthritis - painful knee –> wrist
pustular rash
tendonitis
how does opthalmia neonatorum differ in chlamydia and gonorrhoea
chlamydia = after first 1-2 weeks of life
gonorrhoea = after first few days of life
Ix of gonorrhoea
gold standard = culture
usually diagnosed with NAAT
Tx of gonorrhoea
IM ceftriaxone
cause of syphilis
treponema pallidum
stages of syphilis with Sx & buzzword for each
primary = painless chancre (ulcer)
secondary = unwell, condyloma lata, lymphadenopathy, maculopapular rash
latent = nothing
tertiary = gummatous disease, aortitis, neurosyphilis, tabes dorsalis
what are conyloma lata
greyish, painless, wart like lesions in genitals or mouth
** buzzword for secondary syphillis
what is gummatois disease
erosion through cartilage in mouth
classic buzzword sign of neurosyphilis
argyll robertson pupils
(accomodation but not constriction)
what is tabes dorsalis
degeneration of spinal cord
Tx of syphillis
IM benzylpenecillin
what reaction can occur upon Tx of syphillis and why
Jarish - Herxheimer reaction **buzzword
- killing of bacteria releases toxins that make pt feverish / unwell for a few days
where does the rash of secondary syphillus affect
palms and soles of feet
testing in primary syphillis
darkfield microscopy of chancre sample (** buzzword) and look under microscope
if not possible:
- non treponemal - VDRL, RPR
- treponemal - TPHA, TP-EIA
cons of non treponemal tests for primary syphillis
not specific for syphilis, can react to like HIV etc
cons on treponemal tests for syphilis
stay positive even after primary syphillis treated - can cause confusion in latent
how is adequate treatment of syphillis confirmed
4x reduction in non treponemal titre
organism causing chancroid
haemophilus ducreyi
buzzword for chancroid
painful ulcers
lymphadenopathy
tropical regions
organism causing donovanosis / granuloma inguinale
klebsiella granulomatis
buzzwords for donovanosis
painless beefy red ulcers
tropical regions
donovan bodies on histology
buzzwords for TV
yellow-green discharge
strawberry cervix
cause of genital warts
HPV
PC of HSV
painful ulcers with NO lymph nodes
