Week 2 - Sepsis Flashcards
What are antibiotics?
Substances produced naturally by microorganisms which can kill (microbiocidal) or inhibit the growth (microbiostatic) of other microorganisms
What is selective toxicity?
Harming the infectious agent without harming the host’s cells.
e.g. penicillin stops peptidoglycan formation in the bacterial cell wall.
What is the difference between Bactericidal and Bacteriostatic?
- Bactericidal: lyse and kill microbes by directly damaging specific cellular targets.
- Bacteriostatic: inhibit reproduction
What are Cephalosporins and how do they work?
A class of drugs that have the same basic structure as the penicillins but have a broad spectrum of activity. They cause lysis of bacteria by interfering with the ability of bacteria to form cell walls. e.g. Ceftriaxone
Explain how tetracyclines work?
- very broad spectrum ‐ act against G+ and G‐
– bacteriostatic ‐ inhibit protein synthesis
How does penicillin lead to an allergic reaction?
the penicillin molecules become antigens when the breakdown products of penicillin combine with blood proteins to form larger molecules that stimulate the immune system.
What is a major concern with broad spectrum antibiotics?
They destroy normal flora, leading to other microbes resistant to the drug invading the unoccupied body sites and multiplying rapidly. This is called superinfection.
What is the process by which bacteria become antibiotic resistant?
Resistance is due to the possession by bacteria of a resistance gene(s)
Resistance genes stop drug action in a number of different ways: • inactivation of drug by enzyme • alter the drug target • stop entry or increase exit
Resistant genes arise by mutation or plasmid transfer
What is the sequence for putting on and removing PPE?
Putting on: Gown - mask/respiratory - goggles/face shield - gloves
Removing: gloves - goggles - gown - face shield
Define the following terms:
- Sterilisation
- Disinfection
- Antisepsis
- Asepsis
- Sterilisation: complete removal of all forms of microbial life
- Disinfection: process of destroying vegetative pathogens but not necessarily endospores or viruses.
- Antisepsis: chemical disinfection of the skin or other living tissue
- Asepsis: the absence of pathogens from an object or area
What factors affect the removal of microorganisms?
- Number of microbes - die at a constant rate
- Type of microbe - G- bacteria are harder to kill with disinfectants, Mycobacteria are resistant to disinfectants
- Organic matter - pus or vomit protect by covering the microbe
What are the main types of disinfectants?
- Halogens: good against bacteria, viruses, fungi but inactivated by organic matter
- Virkon S: contains potassium peroxymonosulfate and a detergent which increases its effectiveness in dirty conditions
Both bleach and Virkon oxidize proteins to disrupt the cell membrane and have wide spectrum of activity against viruses and bacteria. - Alcohols: good against bacteria, do not penetrate organic matter, act rapidly
- Chlorhexidine: used for disinfection of skin and mucous membranes, good against gram positive bacteria, inactivated by organic matter
What is viral Hepatitis and what is it caused by?
Inflammation and damage to the liver resulting in fever, anorexia, nausea, vomiting and jaundice, maybe liver failure.
Caused by a wide variety of viruses: hepatitis A & E - faecal-oral spread, B/C/D/G - blood-borne
Diagnosis is based on serology
Explain Hep A epidemiology: spread, replication, incubation
Excreted in faeces and contaminates food or water (can also be spread sexually), replicated in intestine wall then goes via blood to the liver producing a cell mediated immune response which causes liver damage. Incubation period is 2-6 weeks followed by symptoms lasting 2-3 months.
Most at risk groups include child care centres, men who have sex with men, IV drug users
Hep A, B and C epidemiology:
Standard, Contact and Droplet precautions for patients with Hepatitis
- A: excreted in faeces, can also spread sexually; virus replicates in intestine wall then goes via blood to the liver; incubation period 2-6 weeks, once you have had it you cannot get it again, vaccine is available
- B: 100x more infectious than HIV, half with chronic hep B are undiagnosed, Hep B vaccine being part of infant immunisation schedule
- C: 20% have moderate to severe liver disease, needle sharing is principle route of hep C in Aus, no vaccine
What are the transmission methods of HIV?
- Sexual contact
- Injection or transfusion of blood or blood products from infected person
- Intrauterine or perinatally from mother to baby, including breast milk
What is the process of HIV infection?
- Portal of entry: break in skin or mucus membrane
- Attaches to cells with CD4 receptor
- Including helper T cells and macrophages - replicates in helper T cells causing cell lysis, undergoes antigenic changes
- mild flu-like symptoms followed by long period of latency
- Virus shifts from blood to lymphoid organs
- AIDS occurs when T cell numbers are too low to mount an effective immune response to infections
What are the clinical features of AIDS?
Opportunistic infections: thrush, reactivating infections (TB, shingles), pneumocystic pneumonia, diarrhoea
Certain cancers: kaposis sarcoma, lymphomas
Use Standard, Contact and Droplet precautions for HIV and AIDS
Ebola background:
- Transmission
- S/S
Reservoir is in wild animals, fatality rate is about 50%
- Transmission: spreads via direct contact through broken skin or mucous membranes with blood, secretions, organs or other bodily fluids
- S/S: incubation period is 2-21 days, humans not infectious until develop symptoms
First symptoms: fever, muscle pain, headache, sore throat
Followed by: vomiting, diarrhoea, rash, kidney/liver failure, internal/external bleeding
How is Meningococcal disease spread?
Contact and droplet
Throat - blood - meninges of brain
Throat - blood - sepsis - DIC - skin rash (non-blanching)
What are the S/S of Meningococcal disease?
- Common: fever, N/V, malaise, confusion, dizziness, irritability, sore throat
- Meningitis only: backache, stiff painfull neck, photophobia, twitching/convulsions, ACS
- Septicaemia only: fever with cold hands, pain in muscles/joints/chest/abdo, pale or grey blotchy skin, tachypnoea, tachycardia and hypotension, diarrhoea, rash that develops into distinctive purple bruising
What is the Rx for MenSept as per CPGs?
- Ceftriaxone - dilute 1g with 9.5mL of Water and administer 1g IV over approx 2mins
- IM: 1g with 3.5mL 1% Lignocaine HCL and administer 1g into upper lateral thigh or other large muscle mass
What is the paediatric dose for Ceftriaxone?
50 mg/kg IV or IM
IV 1 g in 10mL = 100 mg is 1 mL
Once they are 6yrs or 20kg max dose administered
Ceftriaxone:
- PEI
- C/I
- Prec
- Side effects
- PEI: 1. suspected meningococcal septicaemia 2. severe sepsis (consult only)
- C/I: 1. allergy to cephalosporin antibiotics
- Prec: 1. allergy to penicillin antibiotics
- Side effects: N/V, skin rash
What are the three elements of the qSOFA?
- High respiratory rate
- Changes in mental status
- Low systolic blood pressure
Temp is unreliable because it can elevated early and can drop late when in septic shock
What is Disseminated Intravascular Coagulation DIC?
Damage to endothelial lining of blood vessels - activation of blood clotting - excessive clotting and bleeding occur - clotting blocks blood vessels - ischaemia and hypoxia
Consumes clotting factors faster than their replacement from liver, leading to haemorrhage and skin rash
How does multiple organ failure result from sepsis?
- Low BP and clotting/bleeding result in shutdown of organs: brain (confusion), heart (tachy, but CO insufficient), lungs (oedema and resp distress), kidneys (renal failure), anaerobic metabolism leads to metabolic acidosis
What are the Sepsis criteria in the CPGs?
≥2:
- Temp >38 or <36
- HR>90
- RR>20
- BP<90
What is the Rx for septic patients?
- If sepsis suspected and chest is clear and MICA not immediately available: request MICA and NS up to 20mL/kg over 30mins
Inadequate or extremely poor perfusion persists - MICA administers Adrenaline infusion
Define Sepsis and Septic Shock:
- Sepsis: life-threatening organ dysfunction caused by a dysregulated host response to infection
- Septic shock: a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than with sepsis alone.
