W07 - Clinical 3 - Abx, Imm & Prophylaxis, Travel Infection Flashcards
Describe those factors important in deciding when to use intravenous or oral antimicrobials.
Iv more serious
oral switch after prescribing (FOCUS after starting SMART)
Describe the spectrum of action of different antimicrobial groups and the ad- vantages/disadvantages of broad and narrow spectrum antibacterials used singly or in combination.
BACTEROCIDAL
penicillin, gentamicin, vancomycin, ciproflox., metronidazole
BACTERIOSTATIC
doxycycline, clarithromycin, azithromycin, linezolid
Explain the place of monitoring drug levels in antibacterial usage.
Red Man Syndrome - activation of mast cell = histamine therefore Vancomycin dose needs to be monitored
Explain the role of the laboratory in influencing antimicrobial choice.
Testing for susceptibility / resistance via disc or gradient diffusion = MINIMUM INHIBITORY CONCENTRATION
CULTURES before prescribing abx unless severe sepsis or LT infection
Describe the use of antiviral and antifungal agents in contemporary infection practice.
a
CELL WALL INHIBITION
BETA LACTAMS bind PBP and inhibit wall formation
penicillins - wide spectrum
cephalosporins - broad
carbapenems - broad, IV only, Valporate interactions
*MEROPENEM: broad, severe, CF infections
!rash, fever, anaphylaxis
GYCOPEPTIDES: gram +, inhibit peptoglycans in cell wall, poor oral abs.
vancomycin - MRSA, 1st line for pencillin allergy, Inf.Endo.
!Red Man Syndrome - activation of mast cell = histamine therefore Vancomycin dose needs to be monitored
Carbapenem significant interaction
interacts with Sodium Valporate (epilepsy, migraine) = decreased valporate levels
Significance of Co-amox
Combo of beta-lactam and beta lactamase inhibitor
- MSSA
- Klebsiella spp.
- Proteus spp.
- Anaerobes
PROTEIN SYNTHESIS INHIBITION
AMINIGLYCOSIDES = GENTAMICIN
- binds 30S rRNA = bacteriostatic
- depolarise cell membrane = bactericidal
•sepsis
!nephrotox., ototox., neuromuscular blockade
TETRACYCLINES = DOXYCYCLINE
*broad, oral, inhibit protein synth
• SSTI, genito-urinary infection, malaria
!pregnancy - crosses placenta, tooth staining.
MACROLIDES = CLARITHROMYCIN, AZITHROMYCIN
- typhoid fever, CAP, skin/soft tissue infections, atypical pneumonia, STI
- H pylori
- T gondii
!jaundice, ototox., prolonged QT syndrome, GI disturbance
!prego - avoid clari and azi, (erythro not known to be harmful)
LINCOSAMIODES = CLINDAMYCIN
OXAZOLIDINONES = LINEZOLID
Metronidazole
Inhibit DNA synth
- anaerobic organisms: C difficile, Helicobacter,
- parasite: giardia, entameoba
*do not take with alcohol
Co-trimoxazole
Trimethoprim and sulfonamides
* inhibit folic acid synth.
- Pneumocystis jiroveci pneumonia
- Toxoplasmosis
- multidrug resistant organisms
!renal impairment, BM suppression
MRSA sensitive Abx
VANCOMYCIN
CLINDAMYACIN
List the situations for which immunisations are currently recommended.
Childhood schedules
2months = 6in1 + pneumococcal + rotavirus + Men B
3months = 6-in-1 + rotavirus
4 months = 6-in-1 + pneumococcal + Men. B
Special patient groups
Occupational
BCG, influenza, pneumococcal, hep B, varicella-zoster, herpes-zoster
Traveler’s
Outline the characteristics of the vaccines used.
Killed Vaccines = produce stronger immune responses with more doses
- polio
- Hep A.
- Rabies
- Influenza
whereas
LIVE Vaccines = immune response develops over time but plateaus
- MMR. BCG, Varicella-zoster, smallpox
DETOXIFIED EXOTOXIN = treated with formalin becoming a TOXOID
- diptheria, tetanus
SUBUNIT VACCINES
- pertussis
- typhoid
- anthrax
- Hep B
RECOMBINANT VACCINES = DNA (HBsAg) recreated by yeast (via plasmid)
-Hep B. (all new born recieve from 2018 onwards)
Discuss the prevention of disease in the traveller.
GENERAL MEASURES
IMMS
-tetanus, polio, typhoid, hep a., yellow fever, cholera
CHEMOPROPHYLAXIS
- malaria
- post-exposure chemproph. for meningococcal disease
- HIV
- Surgical abx proph.
Significance of Passive Imm
Human normal immunoglobulin
- against Hep A, rubella, measles
- Ig deficiencies
- AuIm disorder tx = Myasthenia gravis
+Post exposure Ig: Hep B, Rabies, Tetanus (anti-toxin) etc.
Chemoroph against malaria
MALARONE
doxycycline (daily)
MEFLOQUINE
sfx = psychosis, epilepsy
CHLOROQUINE + PROQUANIL
Recognise the common features of the most important travel-related infections and how they can be diagnosed and treated.
MALARIA
- fever, rigors, aching bones, abdo pain, headache
- splenomeg., hepatomeg, mild jaundice
=> cerebral malaria, blackwater fever (profound haemolysis and anaemia), pulm oedema, jaundice
-blood films, Ag test, quantitative buffy coat
> Riamet (uncomplicated) or Quinine 7 days
QUININE (IV for complicated) + doxycycline
Chloroquine for other species
TYPHOID FEVER
*salmonella typhi / paratyphi
progresses thru weeks: fever, headache, abdo discomfort, constipation, dry cough
complication = intestinal bleeding, perofration, peritonism, metastatic infection
*culture, bloods, BM culture
> AZITHROMYCIN (oral - uncomplicated)
IV CEFTRIAXONE (complicated)
DENGUE FEVER
*commonest human arbovirus
-suden fever, headache, retro-orbital pain, myalgia/arthralgia
+ macular rash, petichial rash
*thrombocytopenia, leucopenia, ⇧transaminases
> supportive; fresh frozen plasma, platelets
!dengue haemorrhagic fever, shock syndrome
SHISTOSOMIASIS- freshwater snails,
- swimmer itch, invasive (cough, abdo discomfort, splenomegaly, eosinophilia)
- Katayama Fever
*Antibody tests, ova in stools/urine, rectal snip
> PRAZIQUANTEL
+PREDNISOLONE
Understand in principle how to manage the patient returning from a tropical country with a febrile illness - with particular reference to taking a travel history and the indications for patient isolation or early best-guess treatment.
Water exposure and water-related infections
*Shistosomiasis, Liver flukes, hookworms
Signs of Rickettsiosis
(tick typhus) SA, Med, Arabian Gulf
abrupt swinging fever, headache, confusion, endovasculitis, rash (macular, petechial),
> TETRACYCLINE
Viral Haemorrhagic Fever
Ebola, Congo-Crimea, Lassa Fever
ZIKA: flavivirus
- prego = microcephaly
- guillain-barre syndrome
Signs on examination
rash - typhoid, typhus, dengue
jaundice - hepatitis, malaria, Yellow fever
lymph nodes - leishmania, trypanosomiasis
liver - malaria, typhoid, amoebic abscess
spleen – visceral leishmaniasis, typhoid, malaria
