Infectious diseases Flashcards
Which groups of antibiotics can have cross reactivity in those with penicillin allergies?
Cephalosporins - cephalexin, ceftriaxone
Carbapenems - meropenem
What kind of bacteria is metronidazole good at treating?
Anaerobes
Name some macrolide antibiotics
Erythromycin, clarithromycin
Name some tetracycline antibiotics
Doxycyline, lymecyclline
Give an example of a quinolone antibiotics and what are its common side effects?
Ciprofloxacin
Tendon rupture, lowers seizures threshold, prolonged QTc
Why is nitrofurantoin only used to treat lower UTIs?
Gets excreted and concentrated in the urine/bladder, once concentrated it can kill the bacteria but low levels in blood
What antibiotic is commonly used to treat MRSA?
Tecioplanin or vancomycin
What antibiotic is commonly used to treat ESBL?
Meropenem
What is the definition of sepsis?
When body launches a large immune system response to an infection causing systemic inflammation and organ dysfunction
What NEWS2 score should trigger a sepsis review?
> 5 or clinical concern
What is the sepsis 6?
3 out: lactate, blood cultures, urine output
3 in: oxygen to maintain sats, empirical borad spectrum antibiotics, IV fluids
What volume of IV fluids should be given to someone with suspected sepsis?
If lactate >2 or BP <90 give 500ml in less than 15 mins
If lactate <2 consider IV fluids
When should you be concerned about neutropenic sepsis?
Someone with a neutrophil count below 1
Presenting with temperature above 38 is neutropenic sepsis until proven otherwise even in the absence of any other symptoms
What is the management of neutropenic sepsis?
Broad spectrum antibiotics such as Tazocin
Emergency admission to hospital
What kind of bacteria is c.diff?
Gram positive rod - anaerobe
Which antibiotics can cause c.diff infection?
Clindamycin, ciprofloxacin, cephalosporins, carbapenems
What is the presentation of c.diff infection?
Diarrhoea, nausea, abdo pain
If severe can lead to colitis, dehydration and systemic symptoms
How is c.diff diagnosed?
Stool sample
Initially tested for c.diff antigen, if that is positive test for toxins which gives definitive diagnosis
What is the management of c.diff?
1st line = oral vancomycin
2nd line = oral fidaxomicin
What are the complications of c.diff infection?
Pesudomembranous colitis, toxic megacolon, bowel perforation, sepsis
How is HIV transmitted?
Unprotected sex, vertical transmission, bodily fluids
How does Kaposi’s sarcoma present?
Raised purple lesions on skin
What are the features of PCP infection and how is it treated?
Most common opportunisitic infection in HIV
Shortness of breath, dry cough, fever
CXR: bilateral interstitial pulmonary infiltrates
Mangement = co-trimoxazole
What is the most common infective cause of diarrhoea in HIV patients?
Cryptosprodium
A patient with HIV and oesophagitis is likely to have what..?
Oesophageal candidiasis
What symptoms are associated with seroconversion (initial infection) with HIV?
Sore throat, lymphadenopathy, malaise, myalgia, diarrhoea, rash, mouth ulcers
What is the most common opportunistic neuro infection in those with HIV?
Cerebral toxoplasmosis
Imaging will show brain lesions with ring enhancement
At what CD4 count are patients susceptible to opportunistic infections?
<200
When should ART be commenced in someone with HIV?
As soon as diagnosis occurs
Usually two NRTIs plus third agent (can get combined in one tablet)
What is the aim of ART treatment?
Normal CD4 count and undetectable viral load
Can you breastfeed if you have HIV?
The safest option is to avoid breastfeeding as it can be transmitted even if viral load is low
How can HIV transmission be prevented during birth?
if viral load over 50 pre-labour c-section is recommended
If viral load >1000 or unknown IV zidovudine is given as infusion during labour
Prophylaxis can also be given to the baby depending on mothers viral load
When can post-exposure prophylaxis be used and how long is it taken for?
Must be commenced within 72 hours of exposure
ART therapy is given for 28 days
What is the most severe and dangerous type of malaria?
Plasmodium falciparum
What is the presentation of malaria?
Incubation period 1-4 weeks
Fever +/- rigors, fatigue, myalgia, headache, nausea, pallor, hepatosplenomegaly, jaundice
How is malaria diagnosed?
Malaria blood film - thick and thin
3 negative samples over 3 consecutive days are required to exclude malaria
How is malaria treated?
Artemether with lumefantrine if uncomplicated
Artesunate if severe or falciparum malaria
How can malaria be prevented?
Spray, nets, antimalarial medication e.g. doxycyline, proguanil with atovaquone (malarone)
What are the risk factors for infective endocarditis?
IVDU, structural heart pathology, CKD, immunocompromised, previous history of infective endocarditis
What are the common causes of infective endocarditis?
Most common = staph aureus
Strep viridans (common after dental work)
What is the presentation of infective endocarditis?
New or changing heart murmur, fever, fatigue, splinter haemorrhages, Janeway lesions, Osler’s nodes, Roth spots, finger clubbing
What investigations are done in infective endocarditis?
3 blood culture samples are recommended (taken at least 6 hours apart)
Transoesophageal echo
What criteria is used to diagnose infective endocarditis?
Duke criteria
Two major or one major + 3 minor or five minor
What is the management of infective endocarditis?
Liaise with micro/ID
IV broad spectrum antibiotics (amoxicillin and optional gentamicin)
What is the presentation of cellulitis?
Erythema, warm, tense, thickened, oedematous, bullae, can be systemically unwell
What is the management of cellulitis?
If severe admission for IV antibiotics is required
1st line = flucloxacillin (if penicillin allergy clarithromycin)
What are the causes of bacterial meningitis?
Neisseria meningitidis, strep pneumoniae, haemophilus influenzae, group B strep (neonates), listeria (neonates)
What is Kernig’s test?
Lying patient on back, flex one hip and knee to 90 degrees then straighten the knee - will produce pain or resistance to movement in meningitis
What is Brudzinki’s test?
Lying patient flat and gently lifting their head and neck off the bed flexing their chin to chest, causes patient to flex their hips and knees
What is the CSF analysis of a patient with bacterial meningitis?
Cloudy, high protein, low glucose, high neutrophils
What is the CSF analysis of a patient with viral meningitis?
Clear, normal protein, normal glucose, high lymphocytes
When should you CT before an LP in suspected meningitis?
Focal neurological signs, papilloedema or other signs of raised ICP, continuous seizures, GCS <12
When should you not perform an LP in suspected meningitits?
Any neuroimaging findings, continuous seizures, rapidly declining GCS, sepsis or rapidly evolving rash, cardiac or respiratory compromise
What is the emergency treatment given in the community for suspected meningitis?
IM benzylpenicillin (as long as it does not delay transfer)
What is the management of meningitis?
Cefotaxime (+ amoxicillin if under 3 months or over 50 to cover listeria)
+ dexamethasone to reduce frequency and severity of hearing loss
What is given as prophylaxis for close contacts of those with meningitis?
Single dose ciprofloxacin (if close prolonged contact within 7 days of onset of illness)
Alternative is rifampicin
What is encephalitis?
Meningitis + confusion
What are the symptoms of Giardia and how does someone catch it?
Non bloody diarrhoea, abdo cramping/bloating
Associated with swimming in rivers/lakes in India
Who is likely to get cryptosporidiosis and what are the symptoms?
Immunocompromised and HIV patients
Water diarrhoea, cramps and fever
What are the symptoms of campylobacter and who is likely to get it?
Flu like illness as prodrome before bloody diarrhoea, vomiting, abdo pain
Most common cause of infective diarrhoea in UK
What are the symptoms of entamoeba histolytica, where is it endemic and what is the treatment?
Profuse bloody diarrhoea
Endemic in South America - incubation period is long so can present months later
Metronidazole
What are the symptoms of yellow fever and where is it found?
Mild flu like illness –> period of remission –> jaundice, haematemesis, oliguria
Found in Africa and rural areas of South America
What are the symptoms of typhoid?
Systemic upset, abdominal pain, constipation, high fever, bradycardia
Present within 21 days of return from travel - endemic in India
Which valve is most commonly affected in infective endocarditis?
Mitral valve (but tricuspid is most commonly affected in IVDU)
What is the most common pathogen that causes leg cellulitis?
Strep (group B)
If a patient is presenting with recurrent thrush what do you need to test for?
Diabetes
What is the most common cause of traveller’s diarrhoea?
E.coli
