MPL 202 Midterm Review 2 PDF - Blood-borne Pathogens

MPL 202 Midterm Review 2 ======================== **Learning Objectives** 1. Describe the most common blood-borne infections for healthcare workers 2. Explain the most common routes of infection and risk mitigation 3. Reduce infection risk through application of pre-and post-exposure...

MPL 202 Midterm Review 2 ======================== **Learning Objectives** 1. Describe the most common blood-borne infections for healthcare workers 2. Explain the most common routes of infection and risk mitigation 3. Reduce infection risk through application of pre-and post-exposure interventions **Case examples for infectious disease exposures** - **Blood and bodily fluid (BBF) exposure** - Needlestick (NSI) and sharps injuries - Body fluid exposure - **Timing is critical when a blood and bodily fluid exposure occurs** **Needlestick Injuries: Risk Factors** - - **Injuries involving hollow-bore needles: (can contain more pathogens than sharps)** - **During use** - Accessing IV lines - Transfer/processing specimens - Pass/transfer equipment - Collision with sharp or worker - Insertion or removal of needle - **During or after disposal** - In transit to disposal (sharps container should be at POC) - Improper disposal - During disposal - **After use, before disposal** - Activation of safety feature - Recap needle (AVOID THIS) - During clean up - **Most commonly reported causes:** - Careless/accidental - Stuck by other - Rushed **Sharps injuries: Risk Factors** - **Injuries involving solid sharps:** - **During use of item** - Processing specimens - Collision with worker - Manipulating sharp in patient - Handle, pass, transfer equipment or specimen - Suture needle handling - **After use, before disposal** - sharp left in unusual location - during clean up - **during or after disposal** - in transit to disposal - during disposal **HIERARCHY OF CONTROLS** ***From most effective to least effective:*** 1. **elimination --** physically remove the hazard 2. **substitution --** replace the hazard 3. **engineering controls --** isolate people from the hazard 4. **administrative controls** -- change the way people work, process that reduces risk of injury 5. **PPE --** protect worker with PPE **Preventing needlestick/sharps injuries** - **Elimination/substitution:** eliminate and/or reduce needle/sharps use, needleless IV systems - **Engineering controls:** isolate hazard and use sharps disposal containers or devices with safety features - **Administrative (process controls:** committees training, processes (e.g., don't recap needles) - **Personal protective equipment** **Safety syringe requirements** - if you don't have access to the safety syringe, ASK - Occupational Health and Safety Act - OSHA requirement in Ontario **Needlestick/Sharps injuries: pathogens** - pathogens of greatest concern: - HBV = 30% chance -- most common - Vaccination significantly reduces risk of infection - HCV = 3% - HIV = 0.3% **Hepatitis B Virus (HBV)** - **Disease:** hepatitis (inflammation of the liver), cirrhosis, liver failure, liver cancer in chronically infected patients - **Prevalence:** \6 months; \> 90% chronic infection rate in infants, 5-10% in adults - **Treatment:** antiviral management for chronic infection; no cures **Hepatitis C Virus (HCV)** - **Disease:** hepatitis (inflammation of the liver), cirrhosis, liver failure, liver cancer in chronically infected patients - **Prevalence:** 1-1.5% in Canada; higher in marginalized communities - **Transmission:** blood (primarily) - **Incubation period:** 2 weeks to 6 months; avg \~2 months - **Pathogenesis:** 60-70% become chronically infected, 30% clear virus - **Treatment:** curative therapy since 2014; direct acting antivirals **Human immunodeficiency virus (HIV)** - **Disease:** acquired immunodeficiency syndrome (AIDS) if not managed, opportunistic infections, cancers (d/t oncogenic pathogens) - **Prevalence:** 0.2% in Canada, 1.3-7.5% in IVDU, \~25% in MSM (Toronto) - **Transmission:** blood (primarily), unprotected sex - **Incubation period:** 1-2 weeks (acute HIV syndrome; flu like) - **Pathogenesis:** destruction of CD4+ immune cells over \~10 years - **Treatment:** highly-active antiretroviral therapy (HAART); no cures **Summary of blood-borne pathogens** - Symptoms will NOT accompany most HBV, HCV, HIV infections - The risk of acquiring a blood-born infection can be high (e.g. HBV) -- higher among non-vaccinated populations - HBV, HCV, HIV can cause chronic, and life-changing diseases - There are treatment options available for HBV, HCV, HIV, that can improve QoL for infected (antivirals) - Preventative measures **are** available: pre-exposure and post-exposure measures **Pre-exposure prevention blood-borne infections** - Step 1: prevent NSI from happening with routine precautions - If this fails... VACCINES!!! (for HBV) \[no vaccines for HIV AND HCV\] - **HBV:** Vaccine is 95-100% effective - **Publicly funded, 1^st^ dose gr 7, 2^nd^ dose 4 months after first dose** - vaccine contains hep B surface antigen (HBsAg) - HBsAg immunization produces Hep B surface antibody (HBsAb) - HBsAb neutralizes HBsAg preventing infection **Vaccination for HBV** - Completing HBV vaccine series is sufficient evidence of protection (i.e. confirmation not req) with the following EXCEPTIONS: - Immunocompromised, chronic renal disease and on dialysis, healthcare professionals - Documentation of Ab response of [≥]{.math.inline} 10 IU/mL is required in HCP - Once confirmed protected for life (if healthy)! - Need to check titers and give booster dose to match the protective level - Protected even if Ab titer drops below 10 IU/mL -- because the body has amnestic immunity: immune amnesia, is a condition where the immune system forgets how to fight off pathogens after a measles infection **Vaccination for HBV: non-responders** - \~5% vaccinated will not develop immunity following 2 doses - If non-responder: - Complete second vaccination series (i.e. 2 doses) - Retest following second series - If non-responder, provide third dose of vaccine - Retest 50-70% will seroconvert - No Ab response after 3 additional doses = non-responder for life - Counsel alt risk reduction measures **Approach to needlestick injury** 1. **Initial follow-up care:** a. Allow wound to bleed freely (but do not squeeze wound) b. Wash site of injury with soap and water c. Proceed to local ED or OccHealth clinic d. Report exposure 2. **Risk assessment:** to assess next steps (e.g. post-exposure prophylaxis) e. Determine HBV vaccination history AND immune status f. Deep vs. shallow punction; hollow bore needle containing blood g. Pt disease status and body fluid (if known; e.g. high viral load) 3. **Sourced/Exposed assessments:** h. Exposed individual (i.e. nurse): i. Informed consent for HBV, HCV, HIV testing i. Sourced individual (i.e. patient) ii. Informed consent for HBV, HCV, HIV testing iii. Personal risks for HBV, HCV, HIV (e.g. injection drug use) iv. IF testing refused, court ordered testing can be obtained j. Source person unknown or unavailable for testing: v. Assess nature of exposure and potential risk factors 4. **Laboratory testing:** samples should be treated as urgent or STAT (or POC) k. If exposed baseline results are negative repeat testing @ 3 weeks, 6 weeks, 3 months post-exposure l. Window period for blood-borne infections: vi. **HBV: 4-12 WEEKS POST EXPOSURE** vii. **HCV: 1-10 WEEKS POST EXPOSURE** viii. **HIV: 2-4 WEEKS POST EXPOSURE** - **Seroconversion:** the point where you can detect antibodies - **Viral clearance period:** the yellow peak - Anti-HCV will deplete over time if the virus is cleared - Will be anti-HCV positive for a long period of time - RNA test is more accurate and shows up faster - RNA level can fluctuate - At 3 weeks, if RNA level is none = can still be infected - Repeat testing until 6 mths if no RNA = truly negative - If antibodies show up at 6 mths still not infected because antibodies will ween over time until you get to 0 aka seroeversion **Clinical example** - A nurse is collecting blood from an individual with a hx of IV drug use. After completing the draw the nurse attempts to engage the safety feature for the syringe and accidentally sticks herself with the needle. The nurse does not report the incident or follow up with clinical assessment. Nearly 6 months after the incident, the nurse complains of fatigue, stomach pain, dark urine, and a yellow discoloration of her skin and eyes - **Progression of chronic HCV Infection** - A diagram of a normal phase Description automatically generated - RNA detection time should be earlier than that of antibodies - Common serology profile of an infected person -- presence of HCV RNA, and Anti-HCV, indicate present of infection -- chronic because it goes beyond 6 months **Limitations of serology** - False-positive and -negative results are prevalent - Cross-reactivity with similar organisms/pathogens - EBV infection (polyclonal B cell expansion) (mono) - Improper sample handling - Diet (e.g. biotin supplementation) - Human-anti-animal antibodies (e.g. mouse IgG) - Immunosuppression/compromised -- antibodies are low false warning - Heterophile antibodies (e.g. rheumatoid factor) **Approach to needlestick injury** 5. **Post-exposure prophylaxis (PEP):** - HBV: HBV vaccine and/or HBV immunoglobulin (HBIg) - HBV vaccine if Ab \ - HCV: no PEP/vaccine; treat if exposed become chronically infected - HIV: PEP for high-risk exposures - PEP consists of HAART - First dose should be given within 72 hours, and preferably within 2 hours of exposure! 6. **Counselling:** - While awaiting test results, and if source infected with BBI - Use barrier protection during intercourse (e.g. condoms) - Do not donate blood - Do not share toothbrushes, razors, needles, etc. - Keep cuts/abrasions covered until fully healed - Defer pregnancy - Provide reassurance around confidentiality of findings; reduce concerns of stigma **Approach to bodily fluid exposure** - Similar to needlestick injury 1. **Initial follow-up care:** clean site of exposure; proceed to ED; report 2. **Risk assessment:** in general, risk is lower compared to needlestick; a. Low risk if skin is intact/covered; risk higher if skin is broken (including bites) or mucous membrane exposure 3. **Source/exposed assessments 4. Laboratory testing 5. PEP 6. Counselling:** all same as for needlestick injury **Summary of blood/bodily fluid exposure** - Needlestick injuries and bodily fluid exposures happen - If injury/exposure occurs seek appropriate care - Rapid testing source/exposed available to inform management decisions - PEP or treatments are available for ALL blood-borne infections