Study Group Infection

Study Group Notes Thursday, November 9, 2006

Infectious Disorders Vocabulary Inflammation:

The protective response of body tissues to irritation or injury. Inflammation may be acute or chronic; its cardinal signs are redness (rubor), heat (calor), swelling (tumor), and pain (dolor), often accompanied by loss of function. The process begins with a transitory vasoconstriction, and then is followed by a brief increase in vascular permeability. The second stage is prolonged and consists of sustained increase in vascular permeability, exudation of fluids from the vessels, clustering of leukocytes along the vessel walls, phagocytosis of microorganisms, deposition of fibrin in the vessel, disposal of the accumulated debris by macrophages, and finally migration of fibroblasts to the area and development of new, normal cells. The severity, timing, and local character of any particular inflammatory response depend on the cause, the area affected and the condition of the host. Histamine, kinins, and various other substances mediate the inflammatory process. (Mosby’s Dictionary of Medicine, Nursing and Health Professions, 7th ed)

Pathogens:

Any microorganism capable of producing disease.

Antibiotic:

Chemical agents with the ability to destroy or interfere with the development of living microorganisms.

Antipyretic:

Substance or procedure that reduces fever; drugs usually lower the thermo-detection set point of the hypothalamic heat regulatory center with resulting vasodilation and sweating. Widely used antipyretic agents are acetaminophen, aspirin and NSAIDS.

Vaccine:

A suspension of attenuated (killed) microorganisms administered intradermally, intramuscularly, orally, or subcutaneously to induce active immunity to infectious disease.

Jaundice:

A yellow discoloration of the skin, mucous membranes and sclerae of the eyes, caused by greater than normal amounts of bilirubin in the blood. Because people with dark skin sometimes have yellow-tinged sclerae, the hard palate of the mouth is often the best place to assess for jaundice. Persons with jaundice may experience nausea, vomiting and abdominal pain and may pass dark urine and clay-colored stools. Jaundice is a symptom of many disorders, including liver diseases, biliary obstruction and the hemolytic anemias. Useful diagnostic procedures include a clinical evaluation for the signs/symptoms, tests of liver function and techniques for direct or indirect visualization such as x-ray, CT scan, ultrasound, endoscopy or exploratory surgery and biopsy.

Anti-inflammatory:

A substance or procedure that counteracts or reduces inflammation.

Cystitis:

An inflammatory condition of the urinary bladder and ureters, characterized by pain, urgency and frequency of urination, and hematuria. It may be caused by a bacterial infection, calculus, or tumor. Depending on the diagnosis, treatment may include antibiotics, increased fluid intake, bed rest, medications to control bladder wall spasms and--when necessary--surgery.

The “Normal” Immune System Two Categories: Non-specific and Specific

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NON-SPECIFIC: This group of protective mechanisms acts without regard for the nature of the invader. o Skin/Mucus/Cilia…act as a physical barrier to keep antigens, pathogens and microbes out.

o pH…the acid/base status of various structures acts to prohibit the growth of invading pathogens.

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 Stomach/GI  Vagina  Sweat  Skin  Tears  Saliva Lysosomal Enzymes…chemical killer of pathogens  Tears  Saliva  Sweat Leukocytes…macrophages and monocytes circulate throughout the system “patrolling” for pathogens. When an invader is found, macrophages engulf it and destroy it. Inflammatory process…a cascade of events which act to wall off an area invaded by pathogens to keep them from spreading and to destroy the pathogens in the process.  Vasodilation brought about by prostaglandins and histamines causes… • Blood to rush into damaged area bringing leukocytes and thrombocytes (resulting in heat/redness)… • Clotting factors, neutrophils, phagocytes, coupled with the extra blood, cause congestion, which irritates surrounding nerves (resulting in swelling/pain)… • Lysosomal enzymes and neutrophils kill the pathogens along with the infected cells leaving behind debris (pus). Interferon…a chemical produced and dispatched to other cells by virus-infected cells. Interferon attaches to surrounding cells and prevents the virus from replicating in the other cells by blocking translation of the viral RNA. It also activates natural killer cells and macrophages. Natural Killer Cells…a lymphocyte that binds to and kills virus-infected cells. Fever…macrophages secrete chemicals known as pyrogens which cause the hypothalamus to increase body temperature in an effort to create a hostile environment for the pathogen. It also increases the rate of metabolism, which speeds up mitosis…increasing the number of lymphocytes and leukocytes available to fight the infection. Reflexes: Nausea, vomiting, diarrhea, itching, coughing, sneezing. All are reflexes by the body to physically expel an invading pathogen. Other?

SPECIFIC: This group of protective mechanisms works against very specific pathogens. Two types: Cell-Mediated and Humoral Cell-Mediated • Involve T-cells and macrophages. • “Self” markers vs. “Not Self” markers…this is how the T-cells and macrophages recognize foreign invaders • When a macrophage finds a pathogen with a “Not Self” marker on its membrane, the macrophage engulfs it and then displays that invaders marker on its own membrane. • Helper T-cells (T-4) bind to the displaying macrophage and “read” the foreign markers. They then secrete lymphokines which activate Cytotoxic (Killer) T-Cells (T8). Killer T-Cells begin dividing to increase their numbers and then they go hunting for cells that display the same makers as that which match the Helper T-Cell that called them. Killer T-Cells are SPECIFIC to only that particular foreign invader. • Complement…Complement are proteins manufactured by Killer T-Cells which bind to an infected cell and eat a hole in the membrane, causing the cell’s contents to spill out (lysing). • The macrophage/Helper T-Cell/Killer T-Cell action is called the “cell-mediated response”. Humoral Response

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Involves Helper T-Cells and B-cells The signal sent by the Helper T-Cells bound to the displaying macrophage also activates B-cells. The B-cells develop into antibodies which are specific to the pathogen. The antibodies (Y-shaped proteins) attach to the receptors of the pathogen. Each antibody can attach to two pathogens. The antibody/pathogens begin to agglutinate which makes it easier for the Killer T-cells and macrophages to find and kill the pathogens.

Immunity •

Primary vs. Secondary

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Primary…the first time a specific pathogen enters and causes an infection. The cellmediated/humoral response has to be initiated “from scratch” and the process takes several days to weeks.

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Secondary…after antibodies are created specifically for a pathogen, they remain in circulation for years (possibly for life, in some cases) as “memory cells”. Each subsequent infection by that same pathogen will be detected by the memory cells, which cause rapid development of Killer T-cells and antibodies to that pathogen. The subsequent infection is stopped within hours to days.

HEPATITIS Jaundice • •

Jaundice is a symptom rather than a disease. The bilirubin level has to be approximately 3 times the normal levels (2-3 mg/dl) for jaundice to occur.

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Normal total bilirubin level in the adult is 0.1 to 1.2 mg/dl (Kee) Most bilirubin is formed from the breakdown of hemoglobin (from erythrocytes) by macrophages. o Unconjugated (Indirect)  Bound to albumin  Circulates in blood  Is not water soluble  Is not excreted by kidneys in urine o Conjugated (Direct)  In the liver bilirubin is conjugated with glucuronic acid  Is water soluble  Secreted into bile to flow into small intestine  In large intestine, is converted to stercobilinogen/urobilinogen by bacteria • Stercobilinogen colors feces brown • Urobilinogen is returned to the liver and some is excreted in urine Three types of Jaundice… o Hemolytic Jaundice  Due to an increased breakdown of red blood cells  Unconjugated form (circulates in blood)  Caused by blood transfusions, sickle cell crisis, hemolytic anemia. o Hepatocellular Jaundice  Liver’s inability to take up bilirubin from the blood and/or conjugate/excrete it  Hepatocytes are damaged and leak bilirubin  Initially, both conjugated and unconjugated levels are elevated  Caused by hepatitis, cirrhosis and hepatic carcinoma o Obstructive Jaundice  Impeded/obstructed flow of bile through the liver

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Due to swelling/fibrosis of the liver’s canaliculi and bile ducts Caused by liver tumors, hepatitis or cirrhosis • With complete obstruction, stools are clay colored. Assessment  In light-skinned persons, use sclera of eyes and later in skin  In dark-skinned persons, use hard palate of the mouth and inner canthus of eyes  Dark brown or brownish red urine  Ictotest reagent tablets to test presence of bilirubin in urine  Pruritus  

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Hepatitis •

Hepatitis is widespread inflammation of liver tissue. o During acute infection liver damage is caused by cytotoxic cytokines and natural killer cells that cause lysis of infected hepatocytes. o This action results in hepatic cell necrosis (cirrhosis) o Kupffer cells proliferate and enlarge. o Bile flow may be interrupted by inflammation of the periportal areas o Immune system effects include rash, angioedema, arthritis, fever and malaise.

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Acute viral hepatitis (A, B, C, D, E or G) is the most common cause o The presence of specific antigens and antigenic subtypes with development of antibodies to them is the only way to distinguish the difference between types of hepatitis virus. Also caused by… o Other viruses  Cytomegalovirus  Epstein-Barr  Herpesvirus  Coxsackie virus  rubella o Drugs (alcohol) o Chemicals o Autoimmune liver disease RARELY caused by bacteria

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Signs/Symptoms o Many patients have no symptoms (30% of HBV and 80% with acute HCV) o Three phases…

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Preicteric/prodromal phase (1 to 21 days) • Anorexia • N/V • Right upper quadrant pain • Constipation/diarrhea • Deceased sense of taste/smell • Malaise • Headache • Fever • Arthralgias • Urticaria • Hepatomegaly • Splenomegaly • Weight loss

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Icteric phase (2 to 4 weeks) • Jaundice (occurs as bilirubin diffuses into the tissues) – hallmark symptom • Pruritus (results from accumulation of bile salts under skin) • Dark urine • Bilirubinuria (manifested as dark urine) • Light stools (if conjugated bilirubin cannot flow out of liver due to obstruction) • Fatigue • Hepatomegaly with tenderness • Weight loss • Anicteric hepatitis o Viral hepatitis without jaundice or symptoms is called anicteric. o High percentage of HAV infections are anicteric

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Posticteric/convalescent phase (lasts 2 to 4 months) • Begins as jaundice is disappearing • Malaise • Easy fatigability • Hepatomegaly

Diagnosis is usually by antigen or antibody detection with other diagnostic tests… o Elevated liver enzymes (AST, SGOT, ALT, SGPT, GGT o Elevated serum bilirubin o Elevated erythrocyte sedimentation rates o Alkaline phosphatase o Serum protein o Urine urobilinogen or urine bilirubin o Leukopenia o Prothrombin time o Liver biopsy for active chronic hepatitis Collaborative Care o Emphasis is on measures to rest the body and assist the liver in regenerating. o Adequate nutrients and rest are most beneficial for liver cell regeneration  Recommend a well-balanced diet that the patient can tolerate  Small, frequent meals with largest caloric intake at breakfast or when patient’s appetite is best  High calorie, high protein/carbohydrate, low fat diet  Drink 2500-3000 ml per day  Supplement with vitamin B-complex and vitamin K  Rest reduces metabolic demands on the liver o Avoid ALCOHOL. o Avoid drugs detoxified by the liver o Avoid acetaminophen o Avoid OTC medications o Avoid phenothiazines (cholestatic/hepatotoxic effects) o Drug therapy…  Interferon (HBV/HCV) • Must be given IM or SQ only • Side effects are flu-like, alopecia, thrombocytopenia, psych disturbances.  Antiemetics (Dramamine/Tigan) useful in patients with nausea/vomiting  Benadryl or chloral hydrate may be used for sedation. o Goals of treatment:  Relieve discomfort  Resume normal activities  Return to normal liver function without complications

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Nursing Diagnoses related to hepatitis… o Altered nutrition: less than body requirements o Activity intolerance o Body image disturbance o Ineffective management of therapeutic regimen o Risk for infection transmission

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Nursing Interventions related to jaundice and hepatitis… o Assess appetite and adequacy of intake to plan appropriate interventions for altered nutrition.  Offer frequent small meals  Oral care before meals to enhance appetite  High carbohydrate/high protein foods offered at times patient is most likely to eat  Attractive meals in pleasant surroundings  Take weight daily on same scale, at same time of day with same clothing (monitor for weight loss) o Provide rest  Provide diversional activities for patients on bed rest (psychological rest)  Increase activity gradually as tolerated to resume previous activities  Conserve strength by careful monitoring of activity.  Teach patient to monitor and control activities that provoke fatigue. o Patient teaching  Teach patient about illness, prevention, treatment, modes of transmission, diet, avoidance of alcohol, etc.  Teach patient to watch for and report signs of complications (muscle cramps, bleeding gums/stools, worsening of symptoms)  Teach infection control.

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Hepatitis A (HAV) o HAV is an RNA virus that is transmitted through the fecal-oral route.  Incubation period is 15 to 50 days (avg 28)  It is found in feces 2+ weeks before the onset of symptoms  It is found in feces up to 1 week after the onset of jaundice  It is present in the blood only briefly. o Poor hygiene, crowded situations and poor sanitary conditions are risk factors  Food-borne HAV is usually due to contamination of food during preparation by an infected food handler o The greatest risk of transmission occurs before clinical symptoms are apparent o Once recovered (usually 2 to 3 months), person has normal hepatic function and life-long immunity (IgG) o There is no chronic carrier of HAV o Vaccine is available to prevent infection.

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Hepatitis B (HBV) o HBV is a DNA virus that is transmitted by percutaneous route (IV drug use, needle-stick, permucosal exposure to infectious blood and body fluids.  Incubation period is 45 to 180 days (avg. 46 to 96 days)  Infectious for 4 to 6 months o Perinatal transmission from mother to infant can occur.  90% of infants infected at birth develop chronic HBV. o HBV is found in almost every body fluid…  Highest amount of virus found in BLOOD, serum and wound exudates  Moderate amount virus found in semen, vaginal fluid and saliva

Lowest amount of virus found in urine, feces, breast milk, tears, and sweat. • Except: GI bleeding allows HBV to enter feces in high amounts Risk factors include…  Sexual contact with infected person (sex workers/homosexuals at highest risk)  IV drug users  Perinatal transmission (mother to newborn)  Hemodialysis patients  Household members of infected person  Health care/public safety workers  In 20-30% of infections, there in no identifiable risk factor HBV can live on a dry surface for at least 7 days and is much more infectious than HIV/AIDS. HBV can exist in a carrier state for 6 months to a year after infection. 2-10% of infected people develop chronic HBV infections with…  normal or elevated liver enzymes  either no symptoms, low-grade liver disease or severe liver disease  a higher risk of developing hepatocellular carcinoma  cirrhosis of liver Treatment/Prevention…  Vaccination  HBIG (Hepatitis B Immunoglobulin) protects persons exposed within past 48 hours and neonates born to HBV+ mothers  Interferon treats chronic HBV (30-40% effective) • Interferon is taken for 4 months. 

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Side effects include flu-like symptoms (arthralgia, loss of strength, fatigue, headache, myalgia, nausea/anorexia); anemia; depression; alopecia; insomnia; rash; thyroid dysfunction; weight loss Lamivudine…most patients respond favorably, but relapse is high upon cessation of treatment. • Lamivudine is a reverse transcriptase inhibitor taken orally for 1 year • 20% to 30% of patients develop resistance to the drug

Hepatitis C (HCV) o HCV is an RNA virus that is primarily transmitted percutaneously  Incubation period is 14 to 180 days (average of 56) o Risk factors…  60% of cases are IV drug users (90% in Canada)  20% are due to sexual transmission  10% are occupational exposure, hemodialysis patients, or perinatal transmissions  10% have no identifiable cause or risk factors  Possible risks… • Body piercing • Tattoos • Intranasal (cocaine) drug use  70% of HCV infections will become chronic o Treatment/Prevention  No vaccine available  Modify behavior to reduce risks  Screen blood/organ/tissue donors  Use blood & body fluid precautions  Treatment of chronic infection with Interferon is 50% effective, with 50% of those relapsing after treatment stops  Ribavirin is new treatment. Studies suggest combination of Interferon and ribavirin is more effective than Interferon alone.

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Side effects of ribavirin include hemolytic anemia; anorexia; cough; dyspnea; insomnia; pruritus; rash; teratogenicity (affects fetal development)

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Hepatitis D (HDV) o HDV, known as delta virus, is a defective single-stranded RNA virus that cannot survive on its own. o HDV requires HBV to replicate and appears as a co-infection to HBV o HDV is important in clinical virulence • More severe acute disease and a greater risk of fulminant hepatitis (2-20%) compared to HBV alone • However… o HBV/HDV infections are less likely to develop into chronic HBV infections  HBV + HDV can result in a superinfection o Superinfections usually develop into chronic HDV infections o Has a high risk of severe chronic liver disease o May present as an acute hepatitis o Transmission is percutaneous/permucosal, similar to HBV.  However, sexual transmission is much less likely

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Hepatitis E (HEV) o HEV is an RNA virus that is transmitted by the fecal-oral route.  Most common source is drinking contaminated water  15-25% rate of fatality among pregnant women o HEV occurs in developing countries (Mexico, India, Asia, Africa)  Only a few cases in the U.S., and usually by people who travelled to areas where HEV is endemic o There are no serologic tests to diagnose HEV in the U.S.

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Hepatitis G (HGV) o HGV is an RNA virus transmitted parenterally and sexually. o It is the most recently recognized form of hepatitis, but poorly understood o It has been found in some blood donors and can be transmitted by transfusion o HGV usually coexists with other hepatitis viruses, such as HCV.

Hepatitis At A Glance Virus Type Source Risks

Route

A&E Feces Crowded conditions; Poor hygiene/sanitation; Contaminated water/food; Infected food handlers; Sexual contact Fecal/oral

Chronic Prevention

No Vaccine Ensure safe drinking water

Prevention for Health Care Workers

Maintain good personal hygiene Wash hands after contact with patient or removal of gloves Use infection control

B, C, D & G Blood & body fluids IV drug users; Multiple sexual partners; Contaminated blood products; Tattoo/piercing; Bites Percutaneous Permucosal Yes B/D: vaccine C/D: behavior modification C/G: blood donor screening Use infection control precautions Wash hands Reduce contact with blood/body fluid Handle blood as potentially

precautions Get vaccinated

infective Dispose of needles properly or use needleless systems when possible For HBV: Get vaccinated