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Pathology Amber > Microbiology > Flashcards

Microbiology Flashcards

1
Q

What are the 5 ways antibiotics are commonly misused?

A
  • No infection present
  • Selection of incorrect drug
  • Inadequate or excessive dose
  • Inappropriate duration of therapy
  • Expensive agent used when cheaper is available
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2
Q

What are common adverse events associated with Abx reported in upto 5% of hospital patients?

A
  • GI upset
    • Fever & rash
    • Renal dysfunction
    • Acute anaphylaxis
    • Hepatitis
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3
Q

What types of carbapenemase isolates are increasing?

A

OXA-48, NDM, some KPC and VIM

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4
Q

How did Abx resistance change from 2015-19?

A

An increased of 32.5% in resistant key pathogen blood stream infections. And 2.4% increase in the PROPORTION of resistant key pathogen BSI (meaning 21/100 would not be treated by Abx).

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5
Q

What does the choice of appropriate Abx depend on?

A

Choice depends on:
H - host characteristics
A - Antimicrobial sensitivities of the
O - Organism itself and also the
S - site of infection

NOTE: also consider results from Ix culture and local policies and cost

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6
Q

What is the MIC?

A

Minimum concentration of Abx needed to treat the infection

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7
Q

When is an Abx indicated as helpful depending on the MIC and breakpoint?

A

When MIC< Break point

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8
Q

Ideally, when should you collect specimens for culture?

A

Collect specimens for culture prior to starting
antibiotics

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9
Q

How do we identify the pathogen?

A

Gram stain:
• CSF
• Joint aspirate
• Pus
Rapid antigen detection
• Immunofluorescence
• PCR

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10
Q

What will local concentration of the Abx be affected by?

A
  • pH at the infection site
    • Lipid-solubility of the drug
    • Ability to penetrate the bloodbrain barrier (CNS infections)
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11
Q

What route of administration should you choose for Abx?

A

i.v.: Serious (or deep-seated) infection
p.o.: Usually easy, but avoid if poor GI
function or vomiting
Different classes of antimicrobial have
different oral bioavailabilities
i.m.: Not an option for long-term use
Avoid if bleeding tendency or drug is
locally irritant
Topical: Limited application and may cause local
sensitisation

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12
Q

What duration of course should you use for Abx?

A

N. meningitidis meningitis 7 days
Acute osteomyelitis (adult) 6 weeks
Bacterial endocarditis 4-6 weeks
Gp A Streptococcal pharyngitis 10 days
Simple cystitis (in women) 3 days

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13
Q

By which mechanism is ESBL E. coli resistant to ceftriaxone?

1) Impaired uptake of Abx
2) Enzyme inactivation of Abx
3) Alteration of target of Abx
4) Enhanced efflux of Abx

A

Answer = 2) Enzyme inactivation of Abx

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14
Q

What are the commonest groups of B lactam Abx?

A
  • Penicillins
  • Cefalosporins
  • Carbapenems
  • Monobactams (not used much but may increase usage due to resistance)
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15
Q

Which mechanism mediates flucloxacillin resistance in S. aureus?

1) Impaired uptake of Abx
2) Enzyme inactivation of Abx
3) Alteration of the target
4) Enhanced efflux of the Abx

A

Answer: 3
Not 2 as flucloxacillin was designed to be stable to B lactamase from S. aureus. Mechanism is an altered penicillin binding protein.

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16
Q

What gut infection would you give oral vancomycin for?

A

A C. diff infection

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17
Q

What if a patient had a C. diff gut infection and it was colonising their hip?

A

Give oral vancomycin and IV vancomycin

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18
Q

A patient has grown a fully susceptible E. coli in their urine. Which of the following is the narrowest spectrum agent you should de-escalate to?

1) Amoxicillin
2) Ceftriaxone
3) Co-amoxicla
4) Meropenem
5) Piperacillin/tazobactam

A

1) Amoxicillin
2) Ceftriaxone
3) Co-amoxicla
4) Meropenem
5) Piperacillin/tazobactam

Answer = 1 (the others are unnecessarily broad)

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19
Q

When we treat influenza, we dont use HAART like technique i.e. use different antivral drugs together. True or false?

A

True

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20
Q

The influenza vaccine given to those at greater risk of complications from flu in the UK is…

A

A purified fraction containing HA and NA of an inactivated virus

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21
Q

500,000 people die each year from seasonal influenza. The number of deaths from COVID worldwide since January 2020 is…

A

6 million people

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22
Q

A covid patient in ITU is most likely to benefit from…

A

Dexamethasone - a steroid (Remdesavir won’t help at this stage)

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23
Q

What is a bacterial infection most likely to show in the blood results?

A 
Increased CRP 
Increased procalcitonin (PCT)
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24
Q

What are fungi?

a) Eukaryotes with chitinous cell walls and ergosterol containing plasma membranes
b) Small protein packages containing genetic material, some also contain enzymes
c) Single-celled organisms with prokaryotic cells
d) Single-celled organisms that are either free-living or parasitic
e) An organism that lives in or on another organism and benefits by deriving nutrients at the others’ expense

A

a) Eukaryotes with chitinous cell walls and ergosterol containing plasma membranes

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25
Q

What are the 2 main groups of fungi?

A

Yeasts - reproduce by budding and are single-celled organisms
Moulds - reproduce by growing and extending and are multicellular hyphae

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26
Q

What is the most common of fungal infections in humans?

a) Candida spp
b) Aspergillus spp
c) Cryptococcus spp
d) Dermatophytes
e) Pneumocystis jiroveci

A

a) Candida spp

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27
Q

You are on the medicine for the elderly ward. The nurse bleeps you about a patient: “Doctor please come and see patient A2, they are complaining about their painful mouth and their tongue looks strange.”

What does the patient have?

A

Oral candidiasis

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28
Q

The nurse on the medicine for the elderly ward says a patient has a rash on their groin, they ask if you can come and look at it.

What does the patient have?

A

Candidal vulvovaginitis

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29
Q

You are the surgical FY1 on the ward. You receive a bleep from the microbiologist on call. “I’ve had a blood culture come back as positive for Mr C. It’s a yeast - please review the patient and call me back.”

Which one is the yeast and which is the mould?

A

1) Yeast - budding
2) Mould - growing and extending

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30
Q

What are the RF for a candidaemia?

A

Burns

Long lines

Malignancy - haematological

Complicated post-operative period

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31
Q

What invasive candida infections do you treat with Ambisome and Voriconazole?

A

1) CNS infections - disemination/trauma/surgery
2) Endocarditis - abnormal/prosthetic valves/long lines
3) Bone and joint infections - dissemination/trauma

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32
Q

How are cryptococci classified?

A

Serotypes A&D - these affect immunodeficient patients (Cryptococcus neoformans)

Serotypes B&C - these affect immunocompetent patients (Cryptococcus gatti)

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33
Q

A hospital in london makes the headlines for harbouring a pigeon infestation within one of their wards. What is the fungi that patients are at risk from?

A

Cryptococci

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34
Q

What type of ink is used to stain cryptococcus disease in this patient?

A

India ink - used to stain CSF

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35
Q

What is the most common mould in UK clinical practice?

A

Aspergillus

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36
Q

What microorganism is this a culture of?

A

Aspergillus - you can see the hyphae formation and extension

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37
Q

You are the FY1 on a respiratory ward. Your consultant has referred a patient who is experiencing haemoptysis and weight loss. PMHx includes treated pulmonary TB. An X-ray is completed. Explain what has happened.

A

Aspergillus has colonised the preformed cavity within the lung forming an aspergilloma - shown by the area of increased consolidation within the cavity.

Further Ix needed: Sputum sample + MCS Ag testing
Aspergillus Ab testing
Galactomannan
Blood culture + histology

Mx: Voriconazole, Ambisome (for atleast 6/52)

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38
Q

You are the FY1 on the renal team. You have been asked to review a patient who has a cough and SOB. They desaturate rapidly when they start to walk.

You look at their lung X-ray. What is the likely diagnosis?

A

Pneumocystic jiroveci pneumonia

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39
Q

Why might antifungals targeting the cell membrane might not work for a PCP (pneumocystis pneumonia)?

A

Because pneumocystic jiroveci lacks ergosterol within its cell wall/membrane

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40
Q

What does this picture show?

A

Rhinocerebral/CNS mucormycosis - chemosis

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41
Q

What is this condition and what microorganisms cause it?

A

Onchomycosis - caused by dermatophytes fungi - Trychophyton spp, Epidermophyton spp, Microsporum spp.

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42
Q

What is this condition and what microorganism causes it?

A

Pityriasis versicolor - Malssezia furfur

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43
Q

What are the side effects associated with anti fungal drugs?

A

Azoles - abnormal LFTs

Polyenes (amphotericin) - nephrotoxicity

Echinocandins - relatvely innocuous

Pyrimidine analogues - blood disorders

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44
Q

Which of the following viruses is most contagious?

a) ebola
b) HIV
c) Hepatitis C
d) SARS
e) Measles

A

e) Measles

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45
Q

What is the R0?

A

The R0 is the number of people (on average) that one sick person will go on to infect. The R0 for measles is 18. If the R0 is reduced to <1 then transmission is halted.

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46
Q

What is the herd immunity threshold for measles?

HIT = 1-(1/R0)

A

HIT = 1-(1/18)

= 94%

94% of the population must be vaccinated for this to stop the spread of disease and confer benefit to those not immune to the virus.

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47
Q

What is an inactivated vaccine?

A

A whole microorganism destroyed by heat/chemicals/radiation/or Abx.

Examples include Influenza vaccine, Cholera vaccine and Polio vaccine.

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48
Q

Vaccination with a live vaccine should be deferred if…

a) Patient has had Ig within the last 3 months
b) Patient is receiving systemic, high dose steroids
c) The patient is a premature infant
d) The patient is breastfeeding
e) The patient has a family hx of epilepsy

A

a) Patient has had Ig within the last 3 months

and

b) The patient is receiving high dose, systemic steroids

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49
Q

What are attenuated vaccines?

A

These are whole organism vaccines, modified to be less virulent. Examples include: measles, mumps, rubella and yellow fever vaccines.

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50
Q

What is a toxoid vaccine?

A

Inactivated toxic components of the microorganism/attack strategy. Examples: tetanus and diptheria.

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51
Q

What is a subunit vaccine?

A

A vaccine created from a protein component of the microorganism or a synthetic virus-like particle. They lack the viral genetic material and are unable to replicate and cause disease. Examples include hepatitis B and HPV.

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52
Q

When is a child’s first vaccination and what are they given?

A

1st vaccination may be following birth if high risk for TB - give BCG

Then for others 1st vaccination is at 8 weeks/2 months.

They are vaccinated for: DTP + polio + Hib + Hep B
Pneumococcal
Rotavirus
Meningitis B

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53
Q

What are the advantages of inactivated vaccines?

A

Stable

Induce response to multiple antigens

Constituents are clearly defined

Unable to cause infection - can be used in the immunocompromised/suppressed/deficient

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54
Q

What are the disadvantages of inactivated vaccines?

A

Need several doses

Local reactions are common

Adjuvant is needed

Shorter lasting immunity

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55
Q

What are the advantages of live attenuated vaccines?

A

Induce response to multiple antigens

Produce a strong immune response

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56
Q

What are the disadvantages of live attenuated vaccines?

A

Cannot be given to an immunocompromised pt

Can cause illness

Potential for contamination?

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57
Q

What are the advantages and disavantages of toxoid vaccines?

A

Adv: Safe to use in immunocompromised/suppressed/deficient individuals

Stable

Long-lasting immune response

Disadv: Local and systemic reactions

May require several doses and adjuvant to work

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58
Q

What are the advantages and disadvantages of a subunit vaccine?

A

Adv: Does not cause disease - suitable for immunocompromised individuals

Disadv: protein must be picked carefully

Often needs boosting

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59
Q

What is a heterotypic vaccine?

A

Uses a pathogen that infects other animals but does not cause serious illness in humans. Example: BCG vaccine (effective for non-pulmonary TB <16s)

60
Q

What is a viral vectored vaccine?

A

Viral genetic informtation that is contained within a modified larger virus such as an adenovirus. Examples include: Ebola, Janssen, COVID - Aztrazeneca and Oxford

61
Q

What is a nucleic acid vaccine?

A

Uses DNA/RNA from pathogens which provides instructions for protective protein Ag. Examples include Pfizer and Moderna COVID vaccines.

62
Q

What is a conjugate vaccine?

A

Poorly immunogenic Ag is paired with a protein that is highly immunogenic i.e. diptheria/tetanus toxoid. Examples: Hib.

63
Q

What is an advantage of a conjugated vaccine?

A

Long-term protection even in children

64
Q

What are the advantages and disadvantages of viral vectored vaccines?

A

Adv: Good immune response

Cannot cause disease - fine for immunocompromised/suppressed

Disadv: Previous vaccine exposure decreases the subsequent effectiveness of vaccine in future

65
Q

What are the barriers to vaccination?

A

Poor access

Anti-vaccination movements

66
Q

Aside from adjuvants what are common other components of vaccines?

A

Active components, stabilisers, preservatives, trace components. These can cause anaphylaxis.

67
Q

What factors contribute to vaccine response?

A

Vaccine type - Live attenuated = stronger response

Ag nature - polysaccharide/protein/dosage

Vaccine schedule - adequate gap between boosters - shorter gap for elderly or children

68
Q

What are the requirements for Disease eradication using vaccines?

A

1) No animal reservoir
2) Antigenically stable pathogen with only 1/small number of strains
2) No latent reservoir of infection, no integration of pathogen genetic material into host genome
3) Vaccine must induce a long-lasting and effective immune response
4) High coverage in the population is needed

69
Q

What are the side effects of the COVID vaccines?

A

Oxford-Aztrazeneca - Vaccine induced thrombotic thrombocytopenia
Capillary leak syndrome

Pfizer - Lymphadenopathy
Myocarditis/Pericarditis

70
Q

What infectious test is NOT currently included in the screening of pregnant women?

Toxoplasmosis

HIV

Hep B

Syphilis

A

Toxoplasmosis

71
Q

What is the most common cause of early onset neonatal sepsis?

A

Group B streptococcus

72
Q

What is the most common type of meningococcal disease in the UK?

A

Meningitis B

73
Q

What is the commonest cause of death worldwide in children under 5 years?

A

Prematurity and pneumonia

74
Q

What are the genetic material characteristics in Hepatitis A?

A

Single-stranded positive sense RNA genome

75
Q

What is the legal responsibility of the patient/healthcare team when a diagnosis of viral hepatitis is made?

A

Alert health protection team/PHE - it is a notifiable disease in the UK

76
Q

What diagnosis is suggested by the following blood test: anti-HAV IgG -ve, IgM positive?

a) Previous HAV infection
b) Never exposed
c) Acute HAV infection

A

c) Acute HAV infection

77
Q

What are the characteristics of Hepatitis B virus genetic material?

A

Double stranded DNA + reverse transcriptase

78
Q

What is the incubation period of hepatitis B?

A

40-160 days

79
Q

What is the definition of chronic hepatitis B?

A

Persistence if HBsAg for 6 months or more after an acute HBV infection

80
Q

What diagnosis is suggested by the following blood test:

HBsAg -ve

anti-HBc IgG -ve

anti-HBs >1000 iu/ml

A

Previous vaccination with Hepatitis B vaccine

81
Q

What diagnosis is suggested by the following blood test:

HBsAg +ve

anti-HBc IgM +ve

anti HBc IgG -ve

A

Acute hepatitis B infection

82
Q

What proportion of hepatitis B infected adults go on to develop chronic hepatitis B?

a) 10%
b) 50%
c) 90%

A

a) 10%

83
Q

What proportion of hepatitis B infected neonates go on to develop chronic hepatitis B?

a) 10%
b) 50%
c) 90%

A

c) 90%

84
Q

A patient with chronic hepatitis B presents with a mass in the liver. The alfa-feto protein in >2000 iu/ml (normal <6). What is the most likely diagnosis?

a) Cirrhosis
b) Hepatocellular carcinoma
c) Secondary liver metastases

A

b) Hepatocellular carcinoma

85
Q

What should you always check in a hepatitis B infected patient?

A

Check their hepatitis delta virus status! HDV spreads via HBV.

RF: sex work

86
Q

What are the characteristics of hepatitis C?

A

Single stranded +ve sense RNA genoma

Blood-borne transmission

incubation period of 2-6 weeks

87
Q

What proportion o the world population has TB?

A

33%

88
Q

The labarotory calls you saying they have found Acid Fast Bacilli in a clinical sample. What should you do?

A

Start TB therapy - mycobacterium is never a contaminant

89
Q

What are the microbiological characteristics of mycobacteria?

A
  • Non-motile rod-shaped bacteria (bacilli)
  • Relatively slow-growing compared to other bacteria
  • Long chain fatty (mycolic) acids, complex waxes and glycolipids in cell wall (gives structural rigidity and staining characteristics)
  • Acid alcohol fast
90
Q

What is the main trend regarding non-tuberculous mycobacteria epidemiology?

A

On the rise

Due to increase in conditions and treatments that render pt’s immunosuppressed - malignancies, autoimmune diseases etc

We also tend to inoculate patients with foreign bodies more often - incidence has therefore been on the rise for the last few decades

91
Q

What are the RF for infection with non-tuberculous mycobacteria?

A

COPD, Asthma, Bronchiectasis, Previous MTB infection, Cystic fibrosis, lung cancer

92
Q

What are the features of non-tuberculous mycobacterium infection?

A

Lung disease: pulmonary sx, nodular/cavitary opacities, multifocal bronchiectasis with multiple small nodules

93
Q

What was the most common cause of death pre-COVID?

A

Mycobacterium Tuberculosis

94
Q

A 23 year old male is a close contact of a person with smear +ve pulmonary TB. What is his life chances of developing TB?

A

10% (provided that you are HIV negative - if HIV +ve then 10% each year)

95
Q

How is mycobacterium tuberculosis transmitted?

A

Droplet nuclei - airborne

<10um particles

Suspended in the air

These reach the lower airway macrophages

Infectious dose 1-10 bacilli

3000 infectious nuclei are released with a cough or talking for 5 mins

Air also remains infectious for 30 mins after these activities ^

96
Q

What are the RF for reactivation with TB?

A

Immunosuppression

Chronic alcohol excess

Malnutrition

Ageing

97
Q

What are the tests for latent TB?

A

Tuberculin skin test (Mantoux test)

IGRAs - Interferon Gamma Assay

98
Q

What are the first line medications for pulmonary TB?

A

2 months: Rifampicin + Isoniazid + Pyrazinamide + Ethambutol

4 months: Rifampicin + Isoniazid

99
Q

What are the challenges with treating HIV and TB?

A

Timing for tx initiation

Drug interactions

Overlapping toxicities

Duration of tx and adherence

Healthcare resources

100
Q

Why do we worry about bacteriuria in children and pregnant women?

A

Children - may have underlying structural abnormality

Pregnant women - Gravida urethra is a slightly different structure to normal one, increased chorioamnionitis risk in pregnant women with bacteriuria

101
Q

Define bacteriuria

A

The presence of bacteria in the urine

102
Q

Define cystitis

A

Inflammation of the bladder, often caused by infection

103
Q

Define uncomplicated urinary tract infection

A

Infection in a structurally and neurologically normal urinary tract. This is generally a lower urinary tract infection.

104
Q

Define complicated urinary tract infection

A

Infection in a urinary tract with functional or structural abnormalities (including indwelling catheters - becomes colonised - gravida urethra and calculi)

105
Q

Which of the following cell types on a microscopy suggests and poorly taken urine sample?

a) WBCs
b) Squamous epithelial cells
c) RBCs

A

b) Squamous epithelial cells

106
Q

What type of cells are these?

A

Squamous epithelial cells of the urethra in a urine sample

107
Q

Which of the following dipstick parameters is a product of nitrate reductase and suggestive of a UTI?

a) Blood
b) Protein
c) Leucocytes
d) Nitrites

A

d) Nitrites

108
Q

Define zoonoses

A

Diseases and infections which are transmitted naturally between vertebrate animals and man

109
Q

What is the pathogen responsible for Q fever (Atypical pneumonia spread by farm/wild animals in tropical setting)?

A

Coxiella burnetii

110
Q

What zoonoses are present in UK and apread via farm/wild animal contact with humans?

A

Salmonella

Campylobacter

111
Q

What pathogen causes Rabies?

A

A lyssa virus - rhabdovirus

112
Q

A 35 year old patient presents with abdominal cramps and dirrhoea after a BBQ. What is the most likely source?

a) Beef
b) Pork
c) Chicken
d) Unpasteurised cheese
e) Playing with the tortoise

A

c) Chicken

113
Q

A 35 year old patient presents with fever after a bat bite. What potential infection is most concerning?

a) Spirillum minus
b) Hanta virus
c) Lassa virus
d) Rabies virus
e) Streptobacillus monoiliformis

A

d) Rabies virus

114
Q

A 35 year old patient is suspected of having a Brucells infection in their right psoas after drinking unpasteurised goats milk. What is the first Ix to obtain?

a) Blood culture
b) Psoas pus culture
c) Serology
d) Whole blood PCR
e) Psoas muscle histopathology

A

a) Blood culture

115
Q

A 35 year old patient presents with a fever of 38.8 degrees c after return from 3 months in Rwanda, when they co-habited in a hut with a family and their livestock. How should this patient be managed?

a) Admit to a bay
b) Transfer to HCID unit at Royal Free
c) Admit into side room
d) Discharge
e) Discharge to return to infectious diseases clinic in 3 days

A

c) Admit into a side room

116
Q

What are the main features of HIV disease in children?

A

Severe oral thrush

Parotitis - swelling of parotid glands

Failure to thrive

117
Q

What are the 3 levels of surgical site infection (wound infection)?

A

1) Superficial incisional - affects the skin and the subcutaneous tisue
2) Deep incisional - affects fascial and muscle layers
3) Organ/space infection - affects any part of anatomy other than the incision

118
Q

What are the most common pathogens infecting the surgical site?

A

Staphylococcus aureus (MSSA and MRSA)

Escherichia coli

Pseudomonas aeruginosa

119
Q

Patient admitted in February 2012 with subarachnoid and subdural haemorrhage that was treated with decompressive craniectomy and then cranioplasty with titanium plate.

Later in the year, they were admitted with a large subdural collection with midline shift. They had the abscess evacuated and the titanium plate removed - underneath, there was a severe infection with 1-1.5cm thick pus.

On blood agar a yellow (haemolytic) gram positive organism was grown. What is the likely organism? What tx would you give?

A

MRSA - methicillin resistant staphylococcus aureus

IV linezolid

120
Q
A
121
Q

What are important considerations to take when planning operation to reduce the risk of surgical site infection?

A

Age of pt (risk increases with age up till 65 and is significant RF for >75)

ASA score i.e. of 3 or more

Diabetes - HbA1C < 7

Malnutrition

Low serum albumin

Radiotherapy and steroid use

Rheumatoid arthritis - stop disease modifying drugs 4 weeks before and 8 weeks post-op

Obesity

Prep: encourage pre-op showering, discourage shaving

122
Q

In surgery, when should antibiotic prohoylaxis be given?

A

Abx prophylaxis should be given at the induction of anaesthesia. The bactericidal concentration of the drug should be established in serum and tissues at the time of incision. Additional doses may need to be given if there is significant blood loss or if ther operation is prolonged.

123
Q

Which of the following is associated with a reduced risk of surgical site infections?

a) Hypothermia
b) Shaving the skin
c) HbA1C of 9
d) Showering on the day of the operation
e) Smoking

A

d) Showering on the day of the operation

124
Q

What is the pathophysiology of septic arthritis?

A

Organisms adhere to the synovial membrane, bacterial proliferation in the synovial fluid with generation of a host inflammatory response. Joint damage leads to the exposure of host derived proteins such as fibronectin to which bacteria adhere.

125
Q

Parasitaemia in a patient infected with Malaria is 20%. What treatment would be given?

a) Co-artem
b) Malarone
c) IV quinine
d) IV artesunate
e) Oral quinine

A

d) IV artesunate

126
Q

What is the most important investigation to guide treatment in a patient with Malaria?

a) Blood glucose
b) Lactate
c) Lactate dehydrogenase
d) Parasitaemia

A

d) Parasitaemia

127
Q

How is dengue transmitted?

a) Radio waves
b) Ticks
c) Aedes mosquito
d) Anopheles mosquito
e) Tumbu flies

A

c) Aedes mosquito (black and white stripy)

128
Q

If you get one serotype of Dengue are you still susceptible to other types?

A

Yes

Dengue haemorrhagic fever and shock syndromes can also occur in those previously infected

129
Q

A person who follows the orthodox jewish religion develops seizures during travel abroad.

a) Cysticercosis is possible cause
b) Cysticercosis is not a possible cause

A

a) Cysticercosis is possible cause

130
Q

What are the main principles of cysticercosis control?

A

Meat processing

Slaughterhouse control

Pig treatment

Vaccination

Health education

Cooking education

Sanitation

Taeniasis treatment

Husbandry practices

131
Q

What is driving the TB epidemic?

a) poverty
b) HIV
c) Lack of N95 masks and PPE
d) The antivax movement

A

b) poverty (+ undernourishment)

132
Q

What proportion of patients complete TB tx?

a) 2%
b) 56%
c) 85%
d) 95%

A

b) 56% (Drug resistant cases)
c) 85% (new and relapse TB cases)

133
Q
A
134
Q

What cytotoxin is produced by certain strains of Staphylococcus aureus which kills white blood cells and leads to fulminant infection of the skin and soft tissue (boils and abscesses etc)?

A

Panton-Valentine Leucocidin Staphylococcus aureus

135
Q

What are the clinical features of septic arthritis?

A

1-2 week (relatively short) Hx of red, painful, swollen restricted joint

Monoarticular (90%)

Knee involved (50%)

Pt w rheumatoid arthritis more subtle signs?

136
Q

What is the kocher criteria?

A

Criteria that is highly predictive of a septic arthritis in the hip in children.

Comprising:

Non-weight bearing

Fever >38.5 degrees C

ESR > 40mm/hr

WCC > 12 000 cells/mm3

137
Q

What are the mechanisms of transmission for vertebral osteomyelitis?

A

Haematogenous spread

Exogenous spread

138
Q

What is the commonest cause of prosthetic joint infection?

A

Coagulase negative staphylococci

139
Q

Where do the most common vertebral osteomyelisis infections take place?

A

Lumbar> Cervical> Cervico-theracic

140
Q

How is Creutzfeld Jacob Disease (CJD) treated?

A

You cannot treat to cure

You can manage symptoms - analgesia, anti-epileptics, anto-anxiety drugs

141
Q

What is the commonest form of prion disease?

a) Kuru
b) Iatrogenic CJD
c) Gerstman-Straussler-Sheinker
d) Variant CJD
e) Sporadic CJD

A

e) Sporadic CJD

142
Q

Which statement is not true of sporadic CJD?

a) median survival time is <6 months
b) Tonsillar biopsy is diagnostic
c) EEG usually shows periodic complexes
d) Mean age of onset is 65 years old
e) CSF markers (S100, 14-3-3) of neuronal damage may be elevated

A

b) Tonsillar biopsy is diagnostic

143
Q

When did the vCJD epidemic peak in the UK?

A

2000

144
Q

What are some differences in the diagnostic Ix used for sporadic and variant CJD?

A

In variant CJD, 14-3-3, S100 protein is not useful

In variant CJD, tonsillar biopsy is 100% sensitive and specific

145
Q

Prion genetics: which is true?

a) The vast majority of cases of variant CJS have bee found to be methionine homozygous (MM) at codon 129 or PRNP
b) Familial prion disease does not cause ataxia
c) In familial prion disease, mutations are usually inherited recessively
d) Familial CJD is more rapidly progressive than sporadic CJS

A

a) The vast majority of cases of variant CJS have bee found to be methionine homozygous (MM) at codon 129 or PRNP

146
Q

What types of malaria have Schuffner’s dots and which have Maurer’s clefts within the erythrocytic cells on blood film?

A

Schuffner’s dots (coarse punctate spots) = Ovale and Vivax

Maurer’s clefts = Falciparum

Pathology Amber (6 decks)

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