1 -4 Revision Flashcards by Amy Brown

What are the 6 signs of sepsis?

Slurred speech
Extreme shivering or muscle pain
Passing no urine
Severe breathlessness
I feel like i might die
Skin mottled/discoloured

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What is sepsis?

A life threatening organ dysfunction due to dysregulated host response to infection.

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What is the Sepsis 6 bundle?

Give O2
Take blood culture
Give IV antibiotics
Give fluid
Measure lactate
Measure urine output

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How can sepsis be recognised early?

Raised EWS

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What things are recognised as ‘red flags’ for sepsis?

RR > 25/min
SBP <91 mmHg
HR > 130/ min

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How does sepsis lead to organ ischaemia?

Cytokines initiate the production of thrombin, promoting coagulation. Microvasculature thrombosis leads to organ ischeamia, dysfunction and failure.

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What bacteria are most likely to cause sepsis?

Gram negative bacteria with potent LPS endotoxin

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What antibiotic is commonly used to treat gram -ve sepsis?

Gentamicin

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What type of antibiotic is gentamicin?

Aminoglyceride

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How would you identify haemophilis influenza on a gram stain?

Gram negative

Pleomorphic - coccobacili to long filaments

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Where is h.influenzae a commensal in the body?

Upper respiratory tract

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How is H.influenzae spread?

Respiratory droplets

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What can infection haemophilis influenzae cause in infants and young children?

Meningitis

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What virulence factors does H.influenzae possess?

IgA protease that degrades IgA and allows colonisation of URT mucosa.

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What antibiotic would you used to treat H. Influenzae?

Amoxicillin

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How can H.influenzae infections be categorised?

Disseminated - via blood stream

Contiguous spread - site of colonisation in resp tract

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What contagious spread infections can H.influenzae cause?

Sinusitis
Otitis media
Bronchopneumonia

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What disseminated infections can H. influenzae cause?

** Bacterial meningitis mainly
Epiglottitis
Septic arthritis

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How would you recognise E.coli on a gram stain?

Gram negative rod

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Where is E.coli found in the body?

Normal flora in the colon

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What virulence factors does E.coli have?

Pili or fimbriae - adherence
Generates energy by reducing nitrates to nitrites
LPS
Catalase-positive

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How can a urine dipstick help to diagnose UTI caused by E.coli?

Nitrites positive - gram +ve uropathogens are nitrites negative.

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How are E.coli UTI infections treated?

Trimethoprim

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What is the mechanism of infection for E.coli?

Movement to sterile body site

- Facal/oral route, from contaminated food and water

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What extra intestinal diseases can E.coli cause?

UTI Neonatal meningitis Sepsis, Pneumonia, Shock

What are the presenting signs of cellulitis?

Rubor, Calor, Dolor, Tumor, Fever

What patient factors increase risk of cellulitis?

Elderly Skin breaks - wounds, catheters Compromised immune function

How would you recognise staph aureus on a gram stain?

Gram +ve (purple) cocci clusters

What antibiotic is used to treat skin and soft tissue staph.aureus infections?

Flucloxacillin

How would you recognise neisseria meningitidis on a gram stain?

Gram negative, diplococcus

Where does neisseria meningitis exist as a commensal in carriers?

Nasopharyngeal mucosa

What virulence factors does Neisseria meningiditis have?

1. Pili - aid attachment 2. Polysaccharide capsule 3. LOS released during autolysis -> toxic endotoxin which can cause sepsis

What is the mode of transmission for Neisseria meningitidis?

Inhalation of respiratory droplets

How would a patient with meningitis present?

Severe headache Rigid neck Sensitivity to light Petechial rash -non blanching

How would you treat meningitis caused by neisseria meningitis?

Ceftriaxone - beta lactam which is less susceptible to beta lactamases and accesses the CSF

What type of antibacterial is ceftriaxone?

Cephalosporin beta lactam

Which patients are more at risk of neisseria meningitidis infection?

Young, previously well patients Smokers Recent viral infection Complement deficiency

How would you recognise strep pneumonia on a gram stain?

Gram positive, lancet-shaped cocci | Can be in pairs or chains

What 2 enzyme exotoxins are released from strep pneumoniae?

Autolysin | Pneumolysin

What do autolysin and pneumolysin do?

Autolysin causes cell wall lysis and the release of intracellular exotoxin pneumolysin which attacks cell membrane.

What bacteria is the most common cause of community-acquired pneumonia?

Strep. pneumonia

What other infections does strep.pneumonia cause?

Otitis media Meningitis Bacteraemia/sepsis

How would you treat mild and severe strep.pneumonia infections?

Beta lactam - amoxicillin | Co-amoxiclav if severe

What are staph aureus virulence factors?

1. Cell wall - protein A, fibrinonectin-binding protein 2. Superantigen exotoxins - toxic shock 3. Cytlytic exotoxins - hemolysins 4. Enzymes - coagulase, hyaluronidase, catalase 5. Slime production

How does MRSA develop resistance to beta-lactam antibiotics?

Acquires modified PBP - PBP2a which has low affinity for all beta lactate antibiotics

What infection does epstein-barr virus cause?

Infectious mononucleosis (glandular fever)

What age group is infectious mononucleosis most common in?

15-19 year olds

What is the classic triad of symptoms associated with glandular fever?

Fever Pharyngitis Lymphadenopathy Others - rash, jaundice

What is the structure of EBV?

Enveloped dsDNA virus

What is the initial site of EBV infection?

Oropharyngeal epithelium

How is EBV transmitted?

Saliva

What malignancies is EBV infection associated with?

Burkitt lymphoma | Nasopharyngeal carcinoma

Which cells does EBV infect?

B cells

When would you use chocolate agar?

To grow Haemophilus influenza as it will only grow if blood cells are lysed

What is the best way to diagnose a virus?

PCR

What is the MOA of trimethoprim?

Inhibits folic acid synthesis by inhibiting bacterial dihydrofolate reductase

What are the 4 P's of infection control?

Place Pathogen Patient Practice

What neisseria virulence factor is part of the vaccine and protects against some, but not all serogroups?

Capsule | For some serogroups, the capsule is antigenic but for others (B) the capsule does not trigger a good response.

Which response is likely to be activated by the flu virus?

Cytotoxic T lymphocytes TH1 T cells Antibodies

What feature of staph epidermidis enables it to cause infections on surfaces?

Produces slime that facilitates adherence to prosthetic surfaces such as catheters

Are fungi larger or small than bacteria?

Fungi are larger than bacteria. | Bacteria are larger than viruses.

Where would you take a swab to check if a patient is an MRSA carrier?

Nose swab - MRSA colonises the nose

What characteristic of clostridium allows it to survive outside the host for long periods?

Spore formation - dormant cell, resistant to heat, UV light and chemical agents

What is acute HIV infection characterised by?

A flu-like illness with a mild rash

Which blood cell would you expect to be raised in a viral infection?

T lymphocytes

Which blood cell would you expect to be raised in a bacterial infection?

Neutrophil

What is known as the 'winter vomiting bug'?

Norovirus

What is the endotoxin of neisseria meningitidis?

LPS on the outer membrane

What bacteria is metronidazole active against?

Anaerobic bacteria - c.diff

What 2 toxins does C.difficule produce?

Toxin A - enterotoxin that produces excessive fluid secretion and inflammation of lining of bowel wall Toxin B - cytotoxin that affects protein synthesis in cells

What gram negative bacilli is present in the colon?

Escherichia coli

What personal protection methods can be used when dealing with patients with infections?

Wear gloves Wear apron Wash hands before and after consultation Wash stethoscope

List 4 causes of community-aquired pneumonia.

Strep pneumoniae Haemiphilus influenzae Influenza Staph aureus

What bedside tests can be done to check for UTI's?

Dipstick | Nitrites - some gram negative bacteria reduce nitrates to nitrites