-
what is the magnification of oil stained microscopy?
1000x
-
how to describe the ZN staining with TB?
- blue background
- pink staining - single and clumps
- acid fast bacilli
-
what is first line Rx for TB?
- 4 drugs for 2 months: RIPE
- 2 drugs for 4 months: RI
-
how do you define MDR TB?
resistance to at least rifampicin and isoniazid
-
can you explain open TB
- sputum smear positive is better term
- one of the infected alveoli has burst into major bronchus and he is now expectorating sputum with AFB in it - transmissible organisms to other people
-
when do you admit someone for TB?
- problems with drug compliance
- respiratory problems
- other medical problems
- not if fit and well as long as agree to take drugs and self isolate at home
-
if you admit a TB pt, what do u have to arrange?
- respiratory isolation facility
- negative pressure: is air is sucked into that room so other people on ward don't get the air he breathes out
-
what do you advise about self isolation?
- as it has insidious history - been coughing all over certain people
- don't need to lock him away
- but entire family need to attend clinic, investigated and given prophylaxis
-
how do you manage the patients family?
if had BCG: chest x-ray, if symptoms report them
-
how do you do a mantoux test?
- inject PPD - proteinacious antigen of M Tb intradermally then mark the area and check it 48 hours later
- look for cell mediated/delayed hypersensitivity reaction to a T cell mediated cellular reaction
- measure the induration in mm
-
how do you assess mantoux response?
- up to 10mm reaction to BCG
- >10-12 mm is graded
- >15mm hugely positive
-
what investigation would you do on the children of a patient with TB?
- may not do CXR as they have thymus there and radiation
- may do mantoux test
-
if mantoux is normal and significant contact with TB patient what to do?
- prophylaxis
- Isoniazid & Rifampicin for 3 months
- or Isoniazid alone for 6 months
-
pt comes to you and is really feeling better after 1 month of Rx what do you do?
- do not stop
- have to complete course
- primary drivers for resistance is incomplete or non-compliant
-
is TB vaccine still given in UK?
- not routinely
- only to high risk individuals
- at birth
- individuals who are recent migrants from endemic high risk areas
- eg whitechapel Bangladeshi
- or family history of contact with TB
-
what is the principle for INF gamma release assay (IGRA)?
- replacing or adjunct to mantoux
- principle: draw blood,
- seclude T cells from sample,
- challenge with TB antigens,
- T cells get excited and release more than baseline interferon
-
what is the big advantage of IGRA?
- isolated Ag that stimulates patients T cells as being different form the one used for BCG (ie wont cross react with BCG)!
- so mantoux is confounded by having had BCG, IGRA is not confounded
-
how protected is the BCG vaccine?
- certain areas of the world not protective against post-primary pulm TB
- eg Africa, india - but WHO says still give vaccine as some protection for serious TB eg TB meningitis
- 70% protection in UK
- reactions with other environmental mycobacteria, temperature of keeping BCG
-
what is the main aim of BCG vaccine?
protect from TB meningitis
-
how do you describe erysipelas?
- hard indurated lesion on face
- clearly demarcated
- raised edge
- peripheral fluid blistering formation
-
what organisms cause erysipelas?
- streptococci
- GAS - strep progenies (beta haemolytic - complete haemolysis on blood agar)
-
how is erysipelas different to cellulitis? in term of location and progression?
- more SUPERFICIAL infection
- affects: epidermis and dermis
- progression: more rapid than celulitis
-
name 2 toxin associated syndromes with this organism?
- scarlet fever - erythrogenic toxin
- toxic shock syndrome
-
why would people with erysipelas feel unwell and vomit?
streptococcal toxins
-
what Ix do you do in suspected erysipelas?
- blood cultures
- ASOT = serology (anti streptolysin O titre)
- skin swabs unhelpful generally
-
what is Rx of erysipelas? how do you tailor to pt?
- penicilin
- oral if well
- if systemically unwell need iv benzyl penicllin
-
what is Rx of erysipelas if pen allergic?
- clindamycin or clarythromycin
- oral is ok
-
2 life threatening syndromes associated with GAS?
- necrotising fasciitis
- puerperal fever - post partum - single most important RF is c-section
-
if the Ix is electron microscopy what type of organism does it suggest?
virus
-
what does rotavirus look like?
spokes of a wheel in outer rim of virus
-
what are classic symptoms of rotavirus
- age group
- no blood as non invasive
- diarrhoea
- vomiting
- fever
- these are classic triad of viral diarrhoea
-
if you do not treat rotavirus, what would happen?
- dehydration
- renal failure - acute tubular necrosis
-
what is commonest mode of transmission of rotavirus?
waterborne
-
what is associated with outbreaks
creche, nursery, COTE homes - all suddenly incontinent of faeces
-
what is a carbuncle?
- abscess larger than a boil (collection of abscesses due to failure to control)
- usually has openings draining pus onto skin
-
who gets carbuncles?
- weak immunity
- diabetes, HIV
-
what is usual cause of carbuncle?
staph aureus
-
what is most common location of carbuncle?
neck
-
name 3 toxin assoc conditions
- scalded skin syndrome - skin damage, blisters, skin sheds (more in infants <5)
- PVL - panton valentine leukocidin: cytotoxin destroy WBC, necrosis severe infection
- Toxic shock syndrome
- food poisoning - enterotoxin
-
what is Rx of carbuncle?
- flucloxacillin
- clindamycin if pen allergic
- if very unwell: iv glycopeptide
-
if MRSA and doesn't tolerate glycopeptide what to give?
linezolid - very well orally absorbed
-
pt is about to have hip operation and has nose screen for MRSA. how to explain?
- common carriage sites for MRSA and easily accessible
- lots of people carry MRSA on skin and nose(10-20%)
- if having invasive at risk procedure - at risk of prosthesis and procedure becoming infected with MRSA
- we want to minimise risk before start operation
-
what to do if nose swab is MRSA+?
- suprression regimen
- chlorhexidine bath and shampoo for 5 days
- nasal ointment with mupirocin
-
once suppression regimen is done what to do?
- operation 2-3days after regimen
- don't need to rescreen
-
what other precautions take if nose MRSA+?
- prophylactic against MRSA peri-operatively iv glycopeptide
- done under laminar flow
- strict attention to skin asepsis
- check signs for infection: febrile unable to weight bear, high WBC, rising CRP
-
if prosthesis gets infected what to do?
deal with superficial infection so doesn't get deep seated
-
what are side effects of vancomycin and how monitor?
- nephrotoxicity
- ototoxicity
- measure levels as renally excreted
-
why would you use a MacConkey agar plate?
- G-ve organisms - UTI
- if go pink they are the fermenters
- if stay yellow - non fermenters
-
what is it called when a pregnant lady has >10x5 cfu of e coli in urine but she feels fine?
asymptomatic bacteriuria
-
do you treat asymptomatic bacteria?
- yes in pregnancy
- risk of ascending infection
- causing pyelonephritis
- bladder urine is sterile
-
why do MSU?
- allow first part of stream to wash off normal flora
- catch middle stream which should be sterile
- transport to lab asap
-
why do we treat asymptomatic bacteuria in pregnancy?
- whenever stasis of urine - culture medium
- 1. in pregnancy get incomplete emptying of urine in bladder because of pressure of fetal head
- 2. back pressure of urine pushes urine up ureter into kidney
- 3. progesterone - musculature in valves is lax - so high risk up ureter and into renal pelvis - pyelonephritis
-
why is pyelonephritis such a worry in pregnancy?
- high fever can precipitate pre-term labour
- Low birth, maternal sepsis, pre term labour
-
name 2 antibiotics to Rx UTI in pregnancy?
- cefadroxil
- amoxicillin
- send urine for MC&S to make sure
-
2 abx to avoid in pregnancy for treating UTI and why?
- trimethroprim in early pregnant: folic acid inhibition (can give in early)
- ciprofloxacin (if have to - talk with obstetrician)
- nitrofurantoin: not in late pregnancy as causes neonatal haemolysis
-
what is risk with trimethoprim in pregnancy?
folic acid inhibition in early pregnancy
-
what is risk with nitrofurantoin in pregnancy?
neonatal haemolysis in late pregnancy
-
what is treatment of GE diarrhoea generally?
- shouldn't give abx unless systemically unwell
- ciprofloxacin
-
what is Rx for campylobacter infection?
- erythromycin not cipro
- as cipro is used in chickenfeed so campylo is resistant to it
-
what does campylobacter look like on gram stain?
- gram -ve
- rod
- seagull shaped/curved
-
how do you investigate suspected C-diff diarrhoea?
stool sample for C-diff toxin and routine culture in case other cause
-
how to treat c-diff diarrhoea? and what is overall management?
- stop antibiotic
- start metronidazole oral
- or oral vancomycin
- if nil by mouth which abx iv metronidazole (not vanc as poorly absorbed into gut where we need it)
- source isolate in a side room
- attention to hand washing
- gloves and aprons to deal with pt
- take off gloves and aprons inside room and wash hands with soap and water not alcohol gel
-
if patient has renal problems and suspect c-diff would you be worried about giving vancomycin and why?
- not worried
- oral vancomycin
- not systemically absorbed so not worried about renal failure
- don't need to measure levels
-
OSCE how did i get this infection in my heart?
- organism enter bloodstream from poor dentition or other lesion
- siting on damaged heart valve (rheumatic fever)
- causeing IE
-
how ascertain IE?
echo visualise lesion
-
Rx of IE?
ben pen and gentamicin
-
how long stay in hospital
- MIC of organism
- how susceptible organism is to penicillin and we will work out regimen
- be prepared at least 4 weeks of iv treatment
-
gentamicin toxic drug
- nephrotoxicity
- ototoxicty
- reassure: make sure levels in safe therapeutic margin by titrating dose appropriately according to levels
-
if allergic to penicillin which drug in IE?
vancomycin or teicoplanin
-
what are indications of vancomycin in IE?
- allergic to penicliln
- MRSA IE
- CNS endocarditis in prosthetic valve
-
need prophylaxis for dental procedures if had past IE?
completely perfect set of teeth don't need to prophylaxis
-
what is most common cause of UTI?
e coli
-
what does e coli look like on gram stain?
G-ve rod
-
what would you detect on urine dipstick of UTI?
- leucocyte esterase - shows there are leucocytes there
- nitrites - e coli reduces nitrates to nitrites
-
how to treat community UTI?
trimethroprim or nitrofurantoin 3 days
-
if you see organism was cultured in McCoy cell line and has inclusion bodies on culture what organism likely?
chlamydia as intracellular
-
how to treat chlamydia conjunctivitis in 10day baby?
- erythromycin or azithromycin iv as risk of pneumonia in baby
- wash eye with sterile saline
- not tetracycline as cant give to children - yellow/grey staining of teeth
-
what could you mistake G+ve cocci on gram stain for? how differentiate?
- candida
- see budding of yeast cells - daughter cell bud from mother
-
what are risk factors of candida infection?
- diabetes
- steroids
- broad spectrum antibiotic
- immunosuppressed
-
how do you treat candida pyelonephritis? how long?
- iv fluconazole 2 weeks at least
- repeat urinalysis
- monitor with US too
-
OSCE chickenpox: pregnant mother with other child with chickenpox. can i take child to ANC?
- no as other women there susceptible
- have you had chickenpox?
- child had 4days of illness, can mother go today?
- can if today as not infectious yet - can go up to day 8
- cannot go if > 8 days until 21 days from start of illness
-
what is the incubation period of VZV?
8-21 days
-
what is the infectious period of VZV?
2 days before rash until it is fully scabbed over
-
what is main cause of osteomyelitis?
staph aureus
-
what is empirical treatment of osteomyelitis?
- 2 weeks iv flucloxacillin
- 4 weeks oral flucloxacillin
- oral fusidic acid 6 weeks
-
what would you see on XR of osteomyelitis?
periosteal elevation of affected bone
-
name 4 organisms causing nosocomial pneumonia in ventilated patients?
- pseudomonas
- klebsiella
- acinetobacter
- serratia
-
what is likely source of ventilator assoc pneum organisms?
endogenous - gut
-
name 4 anti psuedomonal traetment?
- piptazobactam
- meropenem
- ceftazidime
- ciprofloxacin (but not good for lung)
-
what is empirical Rx for 1 yr old boy who has fever and vomiting and positive urine culture?
- ceftriaxone iv
- to cover UTI and meningitis
-
what can happen if recurrent UTI in children is not treated?
reflux - acute pyelonephritis and scarring
-
which abx use for pseudomonas UTI?
- ciprofloxacin
- only oral anti pseudomonal
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