Flashcards in Infections Deck (23):
Surgical site infection -
Cause, organisms and Abx
Staph aureus. ?E coli, Pseudomonas, Haemolytic strep.
Septic arthritis -
RF, presentation, Dx
Abnormal joint (RA), immunosuppression, bacteramia (DM, IVDU).
Unwell, febrile, red hot swollen joint, usually knee, can't weight bear.
Blood cultures before Abx. Asiprate joint (50,000 cells/mL), inflam markers. Imaging (effusion).
Septic arthritis -
Bugs and Tx
Staph aureus 46%; Strep 22%; G- like E coli.
Local or haematogenous spread. Subacute Brodie abscess.
Pain, fever, local swelling.
MRI, bone biopsy.
Debride. Remove sequestra and infected bone.
Prosthetic joint infection
Local from wound or systemic from UTI.
Staph, E coli.
Pain, joint failure, "joint was never right".
Radiology: loosening. CRP mildly raised, some white cells in aspirate.
Replace joint again, use cement impregnated with Abx.
IV, Broad spectrum,
eg. Co-amoxiclav + gentamycin.
Define: Pyrexia of unknown origin
>38.3 for 3 weeks, no Dx despite a week of intensive investigations
Causes of classical PUO
- Connective tissue diseases
- Undiagnosed conditions
- Abscesses, endocarditis, TB, complicated UTIs
Causes of healthcare-associated PUO
- C diff
- IV line bacteraemia
- Drugs: vancomycin, serotonergics
- TB / disseminated MAI
- PCP, CMV, cryptococcus, toxo, histoplasma
Observe fever - try not to treat until cause known.
Take cultures before starting empirical Abx (even in neutropaenic sepsis) unless unstable.
- Vasculitis screen: pANCA, cANCA, Rho, La...
- Urine dip, Bence-Jones, casts
- Familial diseases eg. familial mediterranean fever, Fabry's, cyclic neutropaenia
Causes of fever in the returning traveller
- Bacterial diarrhoea
- HIV seroconversion
- Viral haemorrhagic fevers.
Clues to typhoid
Relative bradycardia, spleen, Rose spots.
Signs of Malaria
Common: fever, spleen, nothing.
Rare: coma, shock, liver, focal neurology.
Investigations for Malaria
Thick blood film: detect parasites.
Thin blood film to tell species.
Various antigen tests.
FBC: 70% low Plt, 30% anaemic.
50% deranged LFTs.
Quinine + doxycycline
Artemisin combination therapy
Symptoms of Malaria
Fever + rigors,
Features of severe Malaria
DNA virus (togavirus)
Maculopapular rash - face then trunk = "three day measles". Flu Sx. LNopathy.
Dx: serology on saliva.
Congenital rubella syndrome
Infection before 10/40: deaf, retinopathy, cataracts, glaucaoma, heart disease, mental retardation.
Sometimes spontaneous abortion before 8/40.
No risk after 20/40.
Slapped cheek rash (erythema infectiosum).
Transient aplastic crises, esp in Sickle and Spherocytosis.
Foetus before 20/40: 3% risk hydrops foetalis. Tx intrauterine transfusion. No risk after 20/40.
Flu in pregnancy.
No congenital abnormalities,
but 5x stillbirth and 3x preterm delivery