Infectious Diseases Flashcards
What is the risk of needlestick transmission for:
Hep B
Hep C
HIV
Hep B - 30-60
Hep C - 3
HIV - 0.3
what lab findings are diagnostic for AIDS
CD4 under 200
viral load over 50000
what are some aids defining illnesses
- karposis sarcoma
- PCP pneumonia
- oesophageal candida
- brain lymphoma
- HIV wasting
- HIV encephalopathy
how do you treat PCP
co-trimoxole
what test do you do with someone with suspected neutropenic sepsis?
Abx choice in unknown source?
Look for source:
- cultures - peripheral and anything in body
- urine
- sputum
- cxr
- LP
antibiotic:
Taz 4.5g IV TDS
Gent 5mg/kg IV
Vanc 1g bd IV
how do you minimise CVC insertion complications in someone with sepsis
- peripheral norad pending
- sterile
- check coags
- best operator
- platelets priot
- US guided
- check placement after
- DVT - US
- contact dermatitis - itchy, oozing, bullae
- insect bite - itchy, confluent, in history
- acute gout - severe pain in joint
- drug reaction - erythematous maculopapualr rash on limgs and extremeties
- superficial thrombophlebtis - tracking erythema, cannula presennt
- status dermatitis - weeping, fluid overload, CCF
what abx cover s.aureus and s.pyogenes
fluclox - 500mg QID
cefalexin - 500mg QID
clinda - 450mg TDS
how does probenecid or clavulanic acid work?
Probenacid - decreases renal excretion of drugs that undergo tubulr secretion eg beta lactams
Clav acid - inhibits beta lactamases to protect drug action
what is the benefit of adding abx to I+D of abscess?
not required unless surrounding cellulitis
small benefit of bactrim particularly in those at risk of MRSA
list two positive and one negative finding
positive
sternotomy wires
circular opacity in valve region consistent with valve
multiple opacties ?septic emboli
neg
no pnemunothorax
no consolidation
specific question in fever in returned traveller
- travel history - where and when, resort/rural, aircon or not, protection eg nets or not
- prophylaxis and immunisation status
- bites or exposures eg sexual, tattoos
- character of fever - onset, cyclical etc
- systems review
how do you diagnose malaria?
- antigen tests - rapid but non specific
- blood films - thick (confirm )and thin (for species)
Why is P.falciparium different to other malarial species?
- high parasite burden
- does not have relapse phase as no hypnozoite phase
- many areas with PF are chloroquine resistant
- complications eg ARDS and mortality are higher
what are the complications of severe p.falciparum infection?
- ARDS
- cerebral malaria
- acute renal failure
- hypoglycaemia
- anaemia
- splenic rupture
for fever in returned traveller list specific examination featurs to certain pathogens
- rash - HIV, dengue, chlamydia
- jaundice - hepatitis
- lymphadenopathy - dengue
- hepatomagely - hepatitis
- petichae - dengue, meningitis
- meningism - meningitis
- splenomegaly - p.falciparium
returned traveller likely diagnosis
why
dengue
high WC
low platelets
anaemia
deranged LFTS
what are the two main treatment options for plasmodium falciparum
Artesunate 2.4mg/kg IV then oral
Quinine 20mg/kg IV then oral
- avoid direct physical contact
- triage patient away from others
- PPE
- dedicated staff for the patient
- enter ED via decontamination area and in isolation room
- notify public health, activate any departmental policies
how do you diagnose the following?
list six causes of fever post transplant and an investigative finding
- CNS infection - high opening pressure
- pulmonary infection - CXR
- surgical site infection - collection on US
- c.diff post abx - stool sample
- acute rejection - ARF/deranged LfTS
- infection of implanted organ - blood tests
diagnosis?
Why?
Common causative agents?
fourniers gangrene
- scrotum oedema
- scrotum erythema
- patches of necrotic skin
Agents
* Strep pyogenes
* staph aureus
* polymicrobial anaerobes and gram negstives
What are the components to managing fourniers/nec fasc
- urgent surgical referral for debridement
- IV abx - vanc 1g, gent, fluclox
- IV fluids for BP over 100
- Glycaemic control
- Analgesia eg fent or morp 2.5mg aliquots
what factors may influence decision to start HIV PEP?
time since exposure
type of intercourse
viral load of patient
?pregnancy
what must be discussed with starting HIV PEP?
- not 100%
- need complete adherence
- follow up testing
- signs of seroconversion
- side effects
initial steps in management of bacterial meningitis in child
- IV fluid 20mkl/kg
- IV dex 0.15mk/kg
- IV ceftriaxone 50-100mg/kg
diagnosis?
why?
Other investigations to identify pathogen
bacterial meningitis
high protein
low glucose high WCC with polymorhps
tests
gram stain
cultures
meningoccocal pcr
viral pcr
urine
causes of meningitis in kids
n.meningitidis
h.influenze
strep pneumonae
what examination findings can suggest meningitis?
petichial rash
reduced GCS/delirium/coma
focal neurological signs
photophobia
meningism kernigs or brudinski
What is the stepwise procedure for performing an LP
- consent and consideration of sedation
- mark landmarks - central between superior iliac crest
- prepare equipment - local anaesthetic, sterile drapes, iodine, sterile field, introducerm needle, collection bottles
- prepare staff - to catch bottles
- position patient LL or sat up
- insert local 5-10ml
- Insertion 22-25g spinal needle midline cephalad bevel parallel 20-30degrees and
wait for two loss of resistance
ICP measurement if indicated
Collection CSF 10 drops three sequential tubes
Replace stylet
Apply dressing and ambulate
Send labelled specimens for testing
what features differentiate pre and post septal cellulitis?
Pre Septal
* normal acuity
* normal eye exam
* no opthalmoplegia
* mild upper lid oedema
Post septal
* reduced acuity/colour vision
* diplopia and opthalmoplegia
* headache vomiting
* cns signs
* systemic features of illness
what species can cause septal cellulitis
s.aureus
s.pyogens
h.influenzae
what is the antibiotic therapy for pre and post septal cellulitis
Pre-septal
PO fluclox 12.5mg/kg up to 500mg QID
Post septal
IV cefotaxime 50mg/kg TDS
diagnosis
pre orbital cellulitis
list the complications of pre orbital cellultiis plus and examination finding?
- orbital cellultis - diplopia/opthalmoplegia
- cavernous sinus thrombosis - 3-6 CN palsy
- meningoencephalitis - meningism, drowsy
- bacteraemia - signs of sepsis
diagnosis?
What are some risk factors?
complications
Causative agents?
perichondritis/cellulitis of ear
Risk factors:
otitis externa
insect bite
local trauma
Complications
cartilage necrosis
local abscess
mastoiditis
Causes
s.aureus
s.pyogenes
psuedomonas
management of pyelo
- Fluids aiming map over 65 or BP over 100
- analgesia
- ABX - gent 3-5 mg/kg plus amoxicillin 1g TDS
what pathogens usually cause pyleo
e.coli
klebsiella
pseudomonas
enterococci
list and justify four investigations in pyelo
urine culture - confirm uti
renal tract imaging - ?abnormality as cause eg in males
blood cultures - ?sepsis
renal function - for gent dosing
what causes a rose spot rash?
What feaures of the history would you ask about
Typhoid (salmonella)
History
* immunisation states
* holiday history - location/precautions/bites
* occupation eg food handler
* systems review and symptoms
how is salmonella typhi transmitted?
What are come complications?
fecal oral
Complications
* ileal perforation from peyers patch inflammation
* relapse of fever 2-3 weeks post
* chronic carrier for approx 1 year
* hypovolaemia
abx treatment for s.typhi
IV ceftriaxone 2g daily
IV cipro 400mg BD
what are the risk factors for tetanus prone wound?
bite wound
deep penetrating wound
compound fracture
FB present
soil/dirt present
IVDU needle
avulsed tooth
6hr delay in surgical debridement
what are the indications for giving tetanus IGs with vaccine in high risk wound
over 10 years since vaccine
incomplete vaccine schedule
immunedeficiency
dirty wound
what are the history and exam featues of nec fasc
History
* risk factors eg HIV, T2DM, malignancy, recent surgery
Exam
* pain out of proportion
* pain on passive movement
* weakness of muscle group involved
* parasthesis/anaesthesia
* systemic featuers
* erythema
* discoluration and bullae
* swelling
* induration
investigations and justifications for PID
- BHCG - exclude ectopic
- endocervical swabs - for STD
- Urine PCR - STD
- LFTS - fitz hugh curtis
- blood serology - HIV/syphillis
antibitoic choice for PID?
- Ceftriaxone 2g od IV
- Azithromycin 500mg od IV
- Metronidazole 500mg bd IV
3 abnormalities and interpretation
- erythema under mandible
- erythema to chest
- swelling below mandible to right
Diagnosis
Ludwigs angina (submandibular abscess) with cellulitis to chest
management priorities in Ludwigs Angina
- Analgesia - 2.5mg morphine or similar
- IV abx - IF fluxloc/metronidazole
- Fluids for map over 65 or BP 100
- ct neck to look for abscess
- airway preparation - anaesthetics
- ENT referal
boy climbing tree:
List abnormalities
Diagnosis
3 investigations and justifications
- wound over palmer aspect DIPJ
- erythema extending to thena eminence
- oedema of index finger
- flexion of index finger
Flexor tenosynovitis
Investigations
US - ?FB
swab - ?MRSA
X ray - bone injury
History
* gradual onset
* constant pain
* cloudy fluid
Exam
* generalsied tendeness
* peritonism
* fever
* percussion tenderness
PD fluid WCC
50% neutrophils
WCC over 100
Abx choice for PD peritonitis?
IP vanc 30mg/kg
IP gent 6mg/kg
IP cephazolin 15mg/kg
IVDU:
3 abnormalities
RMZ cavitating lesion
air bronchogram
fluid in horizontal fissure
tiny right pleural effusion
RML pneumonia
infections and non infections causes of this?
Infectious
* S.aureus
* Klebsiella
* TB
* fungal aspergillosis
* PCP
**
Non infectious**
* malignancy
* sarcoidosis
* rheumatoid
* PE
3 initial investigations
sputum for AFB - ?Tb
CT chest - ?infarct, other lesions
cultures - abx guidance
echo - ?IE
list and justify four antimicrobial choices
NB working in flood water in the north
- oseltamivir 75mg BD - flu
- Paxlovid 300/100mg QID - covid
- ceftriaxone 1g OD - severe pneumonia
- Azithromycin 500mg IV OD - severe pneumonia
- flood water ?melodosis - meropenic 1g IV TDS
what are six non respiratory causes of ARDS
- pancreatitis
- trauma
- burns
- massive transfusion
- near drowning
- non resp sepsis
what are the steps in oxygen esclation for pneumonia/ARDS etc
- if asthma COPD give bronchodilators and steroids - back to back 5mg salb and 400mcg ipa nebs plus 200 MG iV hydrocort
- NRB 15l then HFNC 1-2l/kg fio2 100
- BIPAP PS10 peep 6 fi02 1
- intubation - experiences and ARDS settings on ventilator (permissive hypercapneia, fi02 1, 4-6ml/kg TV)
what is a suitable start for ionotropic support?
- norad 4mg in 100ml 5% dextrose starting at 1-5ml/hr and titrate to MAP and urine output 0.5ml/kg/hr
- adrenaline 4mg in 100ml 5% dextrose - 1-5ml/hr
- metoraminoal 0.5mg/1ml boluses
antibiotic options for febrile neutropenia
tazocin 4.5g TDS
or
meropenem 1g IV
risk factors for tumour lysis syndrome
large tumour burden
sensitivity to chemo
haem malignancy
high tumour proliferation rate
renal disease
hyperuricaemia
metabolic features of tumour lysis
renal impairment
hyperuricaemia
hyperkalaemia
hyperphosphatemia
lactic acidosis
hypocalcaemia
tumour lysis treatment
IV hydration
allupurinol
