Infection Flashcards
What is the antibiotic of choice for perioperative abx prophylaxis?
IV Cefalozin (1st gen cephalosporin)
Cefalozin is used for perioperative prophylaxis, allergy to what may mean another abx must be used? Which may be used be used?
Beta lactam allergy
Use clindamycin or vancomycin
Which antibiotics have a beta lactam ring?
Penicillins Cephalosporins Monobactam Carbapenems Carbacephems
In addition to IV Cefalozin, what other antibiotic may be used for perioperative prophylaxis?
IV metronidazole
Which patients may require IV metronidazole in addition to IV cefalozin for perioperative prophylaxis?
Small intestinal obstruction
Appendectomy
Colorectal surgery
What are the most common causes of a post op fever?
Surgical site infections Pneumonia Catheter related UTI Primary blood stream infections Febrile drug reaction
Which types of pneumonia are post op patients vulnerable to?
Ventilator associated
HAP
Aspiration
Which bacteria are commonly indicated in surgical site infection?
First 4 days:
- Group A strep = strep pyogenes
- Clostridium perfringens
> 4 days
- s aureus
> 30 days:
- indolent organisms egs epidermis
What can clostridium perfringens infection lead to?
Necrotising fasciitis
How can surgical wounds be classified? (4)
1) Clean
2) Clean - contaminated
3) Contaminated
4) Dirty / infected
What criteria must be met for a surgical wound to be described as clean?
All of:
- Noninflamed operative wound
- The respiratory, GI, genital and urinary tracts have not been entered during surgery
- Would is closed primary with / without a drain
What is a clean-contaminated surgical wound?
Non inflamed operative wound
The respiratory, GI, genital and urinary tracts have been entered during surgery
What is a contaminated surgical wound?
Fresh, open, accidental wound
Inflamed operative wound without purulent discharge
Clean or clean-contaminated wounds with a break in sterile technique during surgery
What is a dirty / infected surgical wound?
Inflamed operative wound
Purulent discharge
How does the surgical incision site appear necrotising fasciitis present?
Cloudy grey discharge
+/- crepitus (gas in subcutaneous tissue)
What is the abx of choice in clean surgical site infection?
Low risk MRSA = cefazolin
High risk MRSA / beta lactam allergic = vancomycin, daptomycin, or linezolid
What is the abx of choice if strep pygones or c. perfrigens is suspected?
Penicillin and clindamycin
Which antibiotics is associated with c diff development?
2nd and 3rd gen cephalopsorins eg cefuroxime
Historically clindamycin
How does c diff present?
DIarrhoea
Abdo pain
Raised WCC
Risk of toxic megacolon
How is c diff diagnosed?
Stool sample showing toxin
What is the management of c diff?
PO metronidazole for 10-14 days
PO vancomycin if severe / unresponsive
Define pyrexia of unknown origin
Fever >38 for >3 weeks which cannot be diagnosed after a week in hostpiral
List some causes of pyrexia of unknown origin
Neoplasia
- Lymphoma
- Hypernephroma
- Preleukaemia
- Atrial myxoma
Infections
- Abscess
- TB
Connective tissue disorders
What are the three types of influenza virus? Which cause most cases?
A, B, C
A and B are majority
How are children given the flu vaccine?
Intranassally
At 2-3yrs then annually
Live vaccine
How does flu present?
Most asymptomatic Sudden onset high fever Headache Muscle / joint aches Non productive cough Severe malaise
If someone with flu develops a productive cough or raised inflammatory markers?
Bacterial superinfection over influenza
Most commonly s aureus or strep pneumoniae
Whats the management of influenza?
Supportive
Antiviral if high risk (neuraminidase inhibitors eg zanamivir / oselatamivir)
List some complications of flu
Primary influenza pneumonia
- Haemorrhagic pneumonia
- Can progress to ARDS
Secondary bacterial pneominia
- Febrile and productive cough after flu symptoms have improved
- Most pneumoniae
URTI eg AOM, sinusitis, croup
Myositis and rahbdomyolyis
Myocarditis
Encephalitis
How does mumps present?
Fever
Malaisa
Musclar pain
Parotitis - usually initially unilateral but becomes bilateral
How does parotitis present?
Earache
Pain on eating
How is mumps spead?
Resp droplets taken into parotid gland then spreads to other tissues
NB notifiable disease
What is the incubation period and when is mumps infective?
Infective 7 days before and 9 days after parotid swelling starts
Incubation period = 14-21 days
What are some complications of mumps?
Orchitis (postpubertal)
- Usually 4/5 days after start of parotitis
Hearing loss - usually unilateral and transient
Meningoencephalitis
Pancreatitis
What is pertussis? What causes it?
Whooping cough
Bordetella pertussis
How does whooping cough present?
2-3 days of coyza followed by:
Coughing bouts worse at night and after feeding, may be ended by vomiting and associated central cyanosis
Inspiratory whoop
Undiagnosed apnoeic attacks in young infants
What causes an inspiratory whoop?
Forced inspiration against a closed glottis (opening between vocal cords)
What can a persistent cough cause / coughing really hard?
Subconjunctival haemorrhages
Anoxia - leadng to syncope and seizures
How long can symptoms of whooping cough last?
10-14 weeks
How is whooping cough diagnosed?
Nasal swab for bordetella pertussis
What is the management of whooping cough?
<6 months = admit
PO macrolide eg calrithromycin if onset of cough is within the previous 21 days
Offer prophylaxis to household
School exclusion 48hrs after commencing abx or 21 days from onset of symtoms
Pregnant women offered vaccine
What causes malaria?
Plasmodium protozoa
Spread by female Anopheles mosquito
What are the different types of plasmodium?
1) Plasmodium falciparum
2) Plasmodium vivax
3) Plasmodium ovale
4) Plasmodium malariae
Which species of plasmodium causes nearly all of the cases of severe malaria?
Plasmodium falciparum
Other 3 cause ‘benign’
What are some protective factors for malaria?
Sickle cell trait
G6PD deficiency
HLA-B53
Absence of Duffy antigens
How does malaria present?
Flu like symptoms Headache Excessive sweating (diaphoresis) High fever Inc bleeding - thrombocytopenia Haemolytic anaemia - weakness, paleness, dizziness D&V Hepatosplenomagaly Discrete jaundice
Note can present up to a year post travel
Different species of plasmodium cause different diseases, what are these?
Vivax + ovale = Tertian
Malariae = Quartan
What course does the fever take in
Tertian = fever spikes every 48hrs
Quartan = spikes every 72hrs
Falciparum = irregular fever spikes without a noticeable rhythm
How does severe malaira (usually falciparum) cause severe organ dysfunction?
Infected erythrocytes deform and stick to endothelial vessels
This prevents them from being removed by the spleen
These occlude capillaries causing microinfarcts
What organ damage can occur in severe malaria?
Kidneys
- Flank Pain
- Oliguria
- Hemoglobinuria
Cerebral
- Hallucinations
- Confusion
- LOC / coma
HF
Pulmonary oedema
Shock
How is malaria diagnosed?
Blood smear showing parasites
Need at least 3 malaria tests over consecutive days to exclude the diagnosis
How is malaria treated?
Chloroquinine
Quinine
Falciparum = admit
Fever following hosptital work ddx
TB
HIV
Viral hemorrhagic fever (VHF)
Typhus
Fever following sexual exposure ddx
HIV
Hep B and C
Syphillis
Gonorrhoea
Fever following visit to African game park
Tick typhys
Fever following fresh water exposure
Schistosomiasis
Leptopirosis
Fever following caving
Histroplasmosis
Rabies
Fever following contaminated food and water / raw meat / fish
Enteric fever Shigella Salmonella Campylobacter Amoebiasis Helminth infection Hep A and E
Fever following ingestion of unpasteurised milk
Brucella
Listeria
Salmonella
Fever following animal contact
Brucella
Q fever
Fever following air conditioning systems / showers
Leigonella
What investigations are recommended for returning travellers with a fever?
Bloods - FBC, U&Es, LFTs
At least 3 malaria blood films or rapid diagnostic tests over 2 days
Blood cultures
HIV test
Urine and stool MC&S
Serology +/- PCR for dengue, Q fever, Brucella
CXR and US of liver and spleen
What does eosinophilia in a returning traveller indicate?
Parasitic infection
