Infection, nosocomial infection,SIRS MODS for 3rd year MBBS student


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Infection, nosocomial infection,SIRS MODS for 3rd year MBBS student

  2. 2. Micro-organisms are normally prevented from causing infection in tissues by intact epithelial surfaces. These are broken down in trauma and by surgery. Protective mechanism can be divided into: • Mechanical barriers • Chemical: low gastric pH • Humoral: antibodies, complement and opsonins • Cellular: phagocytic cells, macrophages polymorphonuclear cells and killer lymphocytes
  3. 3. Infection Invasion of microorganisms their multiplication and creation of adverse host response by breakdown of local and systemic host defenses. Causes of reduced host resistance to infection 1. Metabolic 2. Disseminated disease 3. Iatrogenic
  4. 4. Metabolic: Disseminated disease: i) Malnutrition (including obesity) Cancer ii) Diabetes ii) Acquired immunodeficiency syndrome (AIDS) iii) Uraemia Iatrogenic: iv) Jaundice i) Radiotherapy Chemotherapy i) ii) iii) Steroids
  5. 5. Classification of sources of infection ■ Primary: acquired from a community or endogenous source ■ Secondary or exogenous (HAI): acquired from the operating theatre or the ward or from contamination at or after surgery
  6. 6. Surgical Infections A surgical infection is an Infection that is unlikely to respond to nonsurgical treatment or occurs in an operated site. .
  7. 7. Examples of 1st group appendicitis , empyema, gas gangrene, and most abscess. Examples of 2nd group Wound infections or SSIs
  8. 8. Surgical Site Infection (SSI) Surgical site infection (SSI) is infection at the site of an operation either at the site of incision or in the organ or body cavity that are manipulated during operation.
  9. 9. Classification 1. Incisional SSI 2. Organ / Space SSI
  10. 10. Classification 1. Incisional SSI i) Superficial incisional SSI: only the skin or subcutaneous tissue of the incision ii) Deep incisional SSI : deep tissues (i.e. fascial and muscle layers) 2. Organ / Space SSI : involving any part of the anatomy(i.e.organ/space) , other than the incision, opened or manipulated during the surgical procedure
  11. 11. Wound infection The infection of a wound can be defined as the invasion of organisms through tissues following a breakdown of local and systemic host defences, leading to cellulitis, lymphangitis, abscess and bacteraemia
  12. 12. A major SSI or major wound infection is defined as a wound that either discharges significant quantities of pus spontaneously or needs a secondary procedure to drain it. The patient may have systemic signs such as tachycardia, pyrexia and a raised white count or delay in return home
  13. 13. Minor wound infections may discharge pus or infected serous fluid but should not be associated with excessive discomfort, systemic signs or delay in return home
  14. 14. Factors that determine whether a wound will become infected or not 1. Host response 2. Virulence and inoculum of infective agent 3. Vascularity and health of tissue being invaded (local ischaemia as well as systemic shock) 4. Presence of dead or foreign tissue 5. Presence of antibiotics during the ‘decisive period’
  15. 15. Risk factors for increased risk of wound infection 1. Malnutrition 3.Immunosuppression i) obesity weight loss 2. Metabolic disease Diabetes Uraemia Jaundice ii) ii) AIDS i) ii) iii) i) Cancer Steroids iii) iv) Chemotherapy v) Radiotherapy 4. Colonisation and
  16. 16. Risk factors for increased risk of wound infection (Cont’) 5. Poor perfusion i) Systemic shock ii) Local ischaemia 6. Foreign body /material 7.Poor surgical technique 8. i) Dead space ii) Haematoma
  17. 17. Nosocomial infection •Acquired infection originating in a patient while in a hospital or other health care facility is known as nosocomial infection. Also known as health care-associated infection (HAI) or Hospital Acquired Infection (HAI).
  18. 18. Nosocomial infection (Cont’) There are four main groups: •Respiratory infections (including ventilator-associated pneumonia) •Urinary tract infections (mostly related to urinary catheters) •Bacteraemia (mostly related to indwelling vascular catheters) •SSIs
  19. 19. Nosocomial infection (cont’) Source of infection 1. Hospital personnel 2. Operation theatre & ward 3. Patient A) Exogenous source ----------- B) Endogenous source
  20. 20. Prevention of Nosocomial infection A) Reducing the sources of pathogens: B) Restricting the transmission: C) Protection of susceptible patients by isolation in a side room
  21. 21. A) Reducing the sources of pathogens: 1. Detection of carriers, their isolation and treatment. 2. Hospital staff those who are suffering from skin disease/sore throat/diarrhoea/dysentery should be kept away from work until completely cured. 3. Barrier nursing 4. Task nursinng
  22. 22. B) Restricting the transmission: 1. Hand washing 2. Adoption of effective aseptic techniques 3. Adoption of proper sterilization and disinfection procedures 4. Droplet infection control by use of face masks, spacing, prevention of overcrowding ,ensuring ventilation etc. 5. Dust control
  23. 23. C) Protection of susceptible patients by isolation in a side room
  24. 24. More common in: • Diabetics • Immunosuppressed pt • Patient on steroid therapy • Patient on life supporting machine • Instrumentation • Pt on artificial prosthesis
  25. 25. Organisms: • Hospital acquired wound infection: S. Aureus is the commonest Others-Pseudomonas, Klebsiella, E. coli, Proteus. • Hospital acquired respiratory tract infection: S. Pneumoniae, Haemophilus, Herpes, Varicella, Aspergillus, Pneumocystis carini • Hospital acquired urinary tract infection: Klebsiella is the commonest
  26. 26. Management: • Antibiotics. • Isolation • Blood, urine, pus for C/S • Blood transfusion, Plasma or albumin therapy • Ventilator support
  27. 27. SIRS: • Systemic inflammatory response syndrome is the body’s systemic response to infection or inflammation characterized by any two of : • Hyperthermia (> 38°C) or hypothermia (< 36°C) • Tachycardia (> 90/ min, no β-blockers) or tachypnoea (> 20/ min) • White cell count > 12 x 109 or < 4 x 109
  28. 28. Cause: • Infection • Multiple trauma • Burn • Pancreatitis
  29. 29. Pathogenesis: • Primary insult ( infection, trauma or surgery, burn,pancreatitis) • Compounding insult • • • • • • • Hypoxia Hypovolumia Nosocomial infection Bacterial and endotoxin leakage from GIT Malnutrition Hyperthermia Hyperglycaemia
  30. 30. SIRS • Increased cytokine production • Failure to localize cytokines • Abnormal NO production • Contact, coagulation and complement activation • Abnormal arachidonic acid metabolism • Neutrophil sequestration and degranulation • Free radical production
  31. 31. Sepsis • Sepsis is defined as the systemic manifestation of SIRS, with a documented infection
  32. 32. Severe sepsis or sepsis syndrome • is sepsis with evidence of one or more organ failures • [Respiratory (acute respiratory distress syndrome), • Cardiovascular (septic shock follows compromise of cardiac function and fall in peripheral vascular resistance), • Renal (usually acute tubular necrosis), • Hepatic, • blood coagulation systems or central nervous system]
  33. 33. MODS : Multiple organ dysfunction syndrome is defined as tissue damage in organs distal to the origin of original injury, is the clinical manifestation of systemic inflammatory response syndrome.
  34. 34. Pathogenesis: • Primary insult • Compounding insult • SIRS • MODS
  35. 35. MODS • cellular dysoxia (i.e. dysfunctional mitochodria) • microvascular occlusion or shunting • tissue hypoxia • cellular dysfunction and or death .
  36. 36. Management: • Primary insult --------------------- unavoidable • Compounding insult ------------------- preventable or treatable. • SIRS --------------------------------------- manageable • MODS is fatal
  37. 37. Multiple system organ failure (MSOF) • Multiple system organ failure (MSOF) is the end-stage of uncontrolled MODS.