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Flashcards in Infections Deck (23):
1

Surgical site infection -
Cause, organisms and Abx

Wound contamination.
Staph aureus. ?E coli, Pseudomonas, Haemolytic strep.
Flucloxacillin.

2

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).

3

Septic arthritis -
Bugs and Tx

Staph aureus 46%; Strep 22%; G- like E coli.

IV cephalosporin/fluclox.
MRSA: vanc.
Drain joint.

4

Osteomyelitis

Local or haematogenous spread. Subacute Brodie abscess.
Pain, fever, local swelling.
MRI, bone biopsy.
Staph aureus.
Debride. Remove sequestra and infected bone.

5

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.

6

Pyelonephritis Abx

IV, Broad spectrum,
eg. Co-amoxiclav + gentamycin.

7

Define: Pyrexia of unknown origin

>38.3 for 3 weeks, no Dx despite a week of intensive investigations

8

Causes of classical PUO

- Infections
- Neoplasms
- Connective tissue diseases
- Undiagnosed conditions
- Abscesses, endocarditis, TB, complicated UTIs

9

Causes of healthcare-associated PUO

- Surgery
- LRTI
- C diff
- IV line bacteraemia
- Drugs: vancomycin, serotonergics
- Immobilisation

10

HIV-associated PUO

- Seroconversion
- TB / disseminated MAI
- PCP, CMV, cryptococcus, toxo, histoplasma
- KS
- Lymphoma

11

PUO workup

Observe fever - try not to treat until cause known.
Take cultures before starting empirical Abx (even in neutropaenic sepsis) unless unstable.
Also:
- Vasculitis screen: pANCA, cANCA, Rho, La...
- Urine dip, Bence-Jones, casts
- Familial diseases eg. familial mediterranean fever, Fabry's, cyclic neutropaenia
- Travel.

12

Causes of fever in the returning traveller

- Malaria
- Dengue
- Typhoid
- Rickettsia
- Bacterial diarrhoea
- HIV seroconversion
- Viral haemorrhagic fevers.

13

Clues to typhoid

Relative bradycardia, spleen, Rose spots.
Gallstones, immunosuppression.

14

Signs of Malaria

Common: fever, spleen, nothing.
Rare: coma, shock, liver, focal neurology.

15

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.

16

Malaria treatment

Mild:
Quinine + doxycycline
Severe:
Artemisin combination therapy

17

Symptoms of Malaria

Fever + rigors,
Flu-like,
Headache,
Back pain,
Myalgia,
N+V.

18

Features of severe Malaria

Impaired consciousness,
Hb

19

Rubella

DNA virus (togavirus)
Maculopapular rash - face then trunk = "three day measles". Flu Sx. LNopathy.
20-50% sub-clinical.
Dx: serology on saliva.

20

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.

21

Parvovirus B19

Slapped cheek rash (erythema infectiosum).
Fever, malaise.
Transient aplastic crises, esp in Sickle and Spherocytosis.
Foetus before 20/40: 3% risk hydrops foetalis. Tx intrauterine transfusion. No risk after 20/40.

22

Flu in pregnancy.

No congenital abnormalities,
but 5x stillbirth and 3x preterm delivery
(so vaccinate).

23

Measles in pregnancy

IUD, miscarriage, preterm delivery, more maternal morbidity.