Infection Flashcards
If someone has a positive HBsAg (Hep B surface antigen), what does this indicate regarding Hep B infection?
They currently have an active infection
What are the aims of HIV treatment?
What does HIV treatment involve?
~ when is it started?
Aims of treatment:
• normal CD4 count
• undetectable viral load
HIV treatment: cART
Treatment involves a combination of 3 of the below:
• Protease inhibitors
• Integrase inhibitors
• Nucleoside reverse transcriptase inhibitors (NRTIs)
• NNRTIs
~ treatment is started as soon as infection is confirmed regardless of their CD4/ viral load count!
If an infection isnt resolving, despite adequate treatment, what condition should you investigate for?
HIV
Explain the routes of transmission of each type of viral hepatitis:
A - faecal-oral route
B - bodily fluids / vertical transmission (mother-baby)
C - bodily fluids
- *D -** bodily fluids
- *** can only survive in patients who also have a Hep B infection ****
E - faecal-oral route
Name 4 antibiotics that are associated with C.difficile infection after their use:
C’s….
• Co-amoxiclav
- Cephalosporins (eg, ceftriaxone)
- Clindamycin
- Ciprofloxacin
What antibiotic is 1st line to treat the first episode (presentation) of a clostridium difficile infection?
If C. diff returns post treatment, what antibiotic is recommended to treat the recurring infection?
10 days of oral Vancomycin
Oral fidaxomicin
What group of bacteria are the commonest (70%) cause of cellulitis?
What is the 1st line antibiotic to treat cellulitis because of the above bacteria?
IF the cellulitis is _hospital acquired_ (eg, from a cannula), what is the most likely causative organism then???
- *Streptococcus**
- (Staphlococci = 30%)*
1st line antibiotic: Flucloxacillin
Hospital acquired: Staph aureus (commonly MRSA!!)
What cells does HIV destroy?
What are the 3 ways that HIV can be tested for in someone?
What 2 things are used to monitor a HIV infection? (below what num. would be abnormal/ end stage disease?)
CD4 T helper cells
1) Antibody blood test - may appear negative until 3 months post exposure
2) PCR: p24 antigen - detects the HIV antigen in the blood
2) PCR: HIV RNA - detects the quantitiy of HIV in the blood (used to measure viral load)
Monitoring:
1) CD4 count
~ below 500 cells/mm3 = abnormal (deficient)
~ below 200 cells/mm3 = end stage disease (AIDs)
2) Viral load
What investigation is essential in order to diagnose meningitis in children?
~ What would be an absolute contraindictation to this?
Lumbar puncture
~ signs of raised ICP
In terms of blood results, viral hepatitis and autoimmune hepatitis will cause a raised AST & ALT +/- bilirubin. What other blood results allow you to distinguish between a viral or autoimmune cause of hepatitis?
Autoimmune hepatitis will always ha a raised IgG but a viral cause won’t.
Name the commonest 1. bacterial and 2 viral causative organisms of tonsillitis:
What would be the treatment of tonsillitis if it is caused by:
- *1. bacteria
2. virus**
Bacterial: strep throat = penicillin
Viral: epstein barr virus (aka, glandular fever) = supportive (analgesia & fluids)
What scoring system is used to assess the severity of a pneumonia?
CURB-65
What are the 6 components of sepsis 6?
~ state the order you would do these in
(take 3, give 3)
1) Give O2 if sats are below 94%
2) Take blood cultures
3) Give IV antibiotics
4) Fluid challenge (give IV fluids)
5) Measure blood lactate
6) Measure urine output
What bacteria is the commonest cause of a community acquired pneumonia?
What is the 1st line antibiotic used to treat a mild/moderate CAP? (if the patient has no allergies)
Strep pneumoniae
Oral amoxicillin
Which inflammatory marker would you expect to be elevated on a FBC if there is a:
- Bacterial cause of infection
- Viral cause of infection
- Bacterial:* Raised neutrophils
- Viral:* Raised lymphocytes
What are the 6 components of sepsis 6?
~ state the order you would do these in
(take 3, give 3)
1) Give O2 if sats are below 94%
2) Take blood cultures
3) Give IV antibiotics
4) Fluid challenge (give IV fluids)
5) Measure blood lactate
6) Measure urine output
If a pregnant woman is HIV positive, is she able to have a normal vaginal delivery?
If a pregnant woman is HIV positive, is she able to breastfeed?
What prophylaxis treatment is given to all babies born to HIV+ women?
Vaginal delivery: ONLY if her viral load is undetectable (< 50 copies/ ml) - otherwise C-section recommended
Breastfeeding: NO. Even if viral load is undetectable, HIV can be transmitted to baby through the breast milk!
Prophylaxis:
• Viral load is undetectable (< 50 copies/ ml) = 1x antiviral for 4 weeks
• Viral load is detectable (> 50 copies/ ml) = 3x antiviral for 4 weeks
Regarding Hepatitis B infection, what do the following biochemical markers mean/ indicate:
- HBsAg (Hep B surface antigen)
- HBeAg (Hep B E antigen)
-
HBcAb (Hep B core antibodies)
~ IgM
~ IgG - HBsAb (Hep B surface antibodies)
- HBV DNA (Hep B virus DNA)
1. HBsAg - indicates an active infection
2. HBeAg - marker of viral infection (so the acute phase of the disease when the virus is actively replicating)
~ the higher the HBeAg, the more infectious the person is ~
3. HBcAb - indicates a past or current infection
~ IgM version of HBcAb = active infection
~ IgG version of HBcAb = past infection (HBsAg will be negative)
4. HBsAb - indicates vaccination / past/ current infection
5. HBV DNA - viral load
To be classed as having neutropenic sepsis, the patient needs to have sepsis and a neutrophil count of what?
Name some medications that can cause neutropenia: (6)
Less than 1x109/L
- Chemotherapy drugs
- Clozapine (schizophrenia)
- Carbimazole (hyperthyroidism)
- Methotrexate (RA)
- Sulfasalazine (RA)
- Hydroxychloroquine (RA)
Name the antibiotic of choice for treating neutropenic sepsis:
Tazocin
What bacteria is the commonest cause of a community acquired pneumonia in:
1. healthy patients
- patients with cystic fibrosis (2)
- Strep pneumoniae
- CF: staph aureus/ pseudomonas aeruginosa
What bacteria is the commonest cause of a UTI?
~ is this a gram positive or gram negative bacteria?
E.coli
~ gram negative
Which 2 antibiotics are commonly used in the treatment of a lower UTI?
~ State which one is used 1st and 2nd line
Which of the above is commonly used in pregnancy?
~ when is it safe to use in pregnancy? (eg, which trimesters)
What medication is used in the remaining trimester of pregnancy when the above medication is no longer suitable?
1st line: trimethoprim
2nd line: nitrofurantoin
~ 1st & 2nd trimesters of pregnancy
Amoxicillin
~ used in 3rd trimester of pregnancy
Which antibiotic is used 1st line for the treatment of a lower UTI?
State the duration of antibiotic treatment of lower UTI in the following:
1. healthy women
- women that are immunosuppressed/ impaired kidney function
- men, pregnancy, catheter related UTI’s
1st line: trimethoprim
1. healthy women: 3 days
2. women that are immunosuppressed/ impaired kidney function: 5-10 days
3. men, pregnancy, catheter related UTI’s: 7 days
Why is nitrofurantoin avoided in the 3rd trimester of pregnancy?
Why is trimethoprim avoided in the 1st & 2nd trimesters of pregnancy?
Nitrofurantoin: it can cause haemolytic anaemia in the newborn
Trimethoprim: it works by inhibiting folate production & fetus’s need folate (folate deficiency can cause neural tube defects)
If cellulitis has a golden-yellow crust, which bacteria does this indicate as the cause of infection?
Staph aureus
What is the commonest bacteria that causes cellulitis?
Name the 2nd commonest bacterial cause of cellulitis:
1: Staph aureus
2: Strep pyogenes (group A strep)
Name the commonest bacterial cause of cellulitis:
Which classification system is used to assess the severity of cellulitis?
~ patient’s in which class would require an admission to hospital?
Name the 1st line antibiotic used to treat cellulitis:
Staph aureus
**Eron classification** (class 1 - 4) ~ class 3 & 4 would require admission
Flucloxacillin
Name the commonest bacterial cause of tonsillitis:
~ what is the 2nd commonest cause?
What is the management of a bacterial tonsillitis?
Group A strep (strep pyogenes)
~ 2nd commonest: strep pneumoniae
Penicillin V
What is the management of a viral cause of tonsillitis?
What is the management of a bacterial cause of tonsillitis? (what if there is a penicillin allergy?)
Viral: simple analgesia for pain & fever control (paracetamol & ibuprofen) + worsening advice
Bacterial: Penicillin V for 10 days
Penicillin allergy: clarithromycin for 10 days
The commonest cause of tonsillitis is viral > bacterial.
Which 2 criteria are used to estimate the probability that tonsillitis is due to a bacterial infection?
~ list the features within each criteria
~ state the score needed in each criteria to consider prescribing antibiotics
CENTOR: score of 3+
Fever over 38 degrees
Tonsillar exudates
NO cough
Tender anterior cervical lymph nodes
Fever PAIN: score of 4+
Fever
Purulent exudate
Attended within 3 days of the onset of symptoms
Inflamed tonsils
No cough/coryzal symptoms
What is otitis media?
What is the management of otitis media?
~ how long does it usually take to resolve?
If the infection fails to resolve with the above management, what would the next step in management be?
Infection of the middle ear
Supportive management (ibuprofen/ paracetamol)
~ usually resolves within 3-7 days
Prescribe amoxicillin if supportive management fails
Sinusitis can be bacterial or viral but commonly self-resolves without treatment.
How long does sinusitis usually last for before it self resolves?
What is the management of sinusitis according to the NICE guidelines:
- symptoms less than 10 days
- no improvement of symptoms after 10 days
- no improvement of symptoms after 10 days & likely a bacterial cause
2-3 weeks
Management:
- symptoms less than 10 days
~ supportive treatment (no antibiotics) - no improvement of symptoms after 10 days
~ 2 weeks of high dose steroid nasal spray
- no improvement of symptoms after 10 days & likely a bacterial cause
~ penicillin V for 5 days
~ clarithromycin if allergic
Which joint is the commonest joint to be affected by septic arthritis?
Name the commonest organism to cause septic arthritis:
~ what would be the likely organism in sexually active people?
Which investigation is required in suspected septic arthritis to make a definitive diagnosis?
KNEE
Staph aureus
~ neisseria gonorrhoea
Joint aspirate → gram staining, crystal microscopy, culture & antibiotic sensitivities
Name the 2 commonest causes of viral gastroenteritis in the UK:
What are the typical symptoms of gastroenteritis? (3)
- Rotavirus
- Norovirus
Symptoms:
~ Nausea
~ Vomiting
~ Diarrhoea
E.coli is a cause of gastroenteritis. By which route is E.coli spread?
The Shiga toxin is produced by which strain of E.coli?
What symptoms does this strain of E.coli produce? (3)
What complication is associated with the Shiga toxin?
Faecal-oral transmission
E.coli 0157
~ abdominal cramps
~ bloody diarrhoea
~ vomiting
Haemolytic uraemic syndrome
Campylobacter jejuni is a common cause of travellers diarrhoea. By which ways can the bacteria be spread? (3)
What are the symptoms of a campylobacter infection? (4)
Transmission:
- raw/ undercooked chicken
- dirty water
- unpasteurised milk
Symptoms:
- abdominal cramps
- diarrhoea +/- blood
- vomiting
- fever
Shigella is a cause of gastroenteritis. By which route is the bacteria spread?
What are the symptoms of a shigella infection? (3)
What toxin can shigella produce?
~ what complication is associated with this toxin?
Faecal-oral route
~ usually faeces contaminating food/water/swimming pools
Symptoms:
- abdominal cramps
- blood diarrhoea
- fever
Shiga toxin
~ haemolytic uraemic syndrome
Salmonella is a cause of gastroenteritis. By which ways can the bacteria be spread? (2)
What are the symptoms of a salmonella infection? (3)
- Eating raw eggs/ poultry (chicken)
- Food contaminated with infected faeces
Symptoms:
- watery diarrhoea +/- mucus/blood
- abdominal pain
- vomiting