Patho Test One PDF

**Immunity** [Autoimmune Disorders] - Development of antibodies against own cells or tissues - Autoantibodies are antibodies formed against self-antigens---loss of self-tolerance. - Disorder can affect single organs or tissues or can be generalized. - Examples: - Hashimoto thyroi...

**Immunity** [Autoimmune Disorders] - Development of antibodies against own cells or tissues - Autoantibodies are antibodies formed against self-antigens---loss of self-tolerance. - Disorder can affect single organs or tissues or can be generalized. - Examples: - Hashimoto thyroiditis, systemic lupus erythematosus, rheumatic fever, myasthenia gravis, scleroderma, pernicious anemia [Systemic Lupus Erythematosus (SLE)] - Chronic inflammatory disease - Affects a number of organ systems - Characteristic facial rash---"butterfly rash" - Signs and symptoms vary because of organ involvement but commonly include: Arthralgia, fatigue, malaise, Cardiovascular problems, Polyuria [Diagnostic test] - Serum antibodies, LE cells, other blood work - Treated by rheumatologist, treatment medication Prednisone (glucocorticoid) - Nonsteroidal anti-inflammatory drugs **[Immunodeficiency]** - Partial or total loss of one or more immune system components - Increased risk of infection and cancer [Primary deficiencies] - Basic developmental failure somewhere in the system [Secondary or acquired immunodeficiencies] - Loss of the immune response from specific causes - Can occur at any time during the lifespan - Infections, splenectomy, malnutrition, liver disease, immunosuppressant drugs, radiation, chemotherapy (cancer) - Predisposition to the development of opportunistic infections Caused by normal flora [Acquired Immunodeficiency Syndrome (AIDS)] - AIDS---chronic infectious disease caused by the human immunodeficiency virus (HIV) - HIV destroys helper T cells---CD4 lymphocytes - Loss of immune response - Increased susceptibility to secondary infections and cancer - Prolonged latent period - Development may be suppressed by antivirals - Current therapies start if HIV infection is diagnosed in the early stages. **Infection** [Microorganisms] - Small living forms - Include bacteria, fungi, protozoa, viruses - Many can grow in artificial culture medium **[Nonpathogenic]** - Usually does not cause disease unless conditions change, Part of normal flora, often beneficial **Pathogens** - Disease-causing microbes [Types of Microorganisms] - Bacteria - Viruses (not living) - Fungi - Protozoa Not Microorganisms or living - Helminth - Prions [Bacteria (test)] - Classified as prokaryotes (which means no nucleus) - No nuclear membrane---no nucleus - Function metabolically and reproduce - Complex cell wall structure - Do not require living tissues/host to survive - Reproduction by binary fission, single bacteria divide into two identical daughter cells [Major Groups of Bacteria (test)] - Bacilli - Rod-shaped organisms - Spirochetes - Include spiral forms and Vibrio spp. - Cocci - Spherical forms, Diplococci (two) Streptococci(chains), Staphylococci (cluster) [Basic Structure of Bacteria] Rigid cell wall which Protects and provides a specific shape Two types that differ in chemical composition: - Gram-positive - Gram-negative Useful in selecting appropriate antimicrobial therapy Cell membrane located inside the bacterial cell wall -- selective permeable External capsule or slime layer, Found in some Outside the cell wall Offers additional protection Flagellae - One or more attached to cell wall - Provide motility for some species Pili or fimbriae - Tiny hairlike structures---found in some bacteria - Assist in attachment to tissue - Transfer of DNA to another bacterium Cell membrane, Inside the bacterial cell wall, selectively permeable Cytoplasm contains: - Chromosome - One long strand of DNA - Ribosomes and RNA Toxins - Exotoxins- Usually produced by gram-positive bacteria - Endotoxins- Present in the cell wall of gram-negative bacteria, released on death of bacterium, Vasoactive compounds that can cause septic shock - Enzymes - Damage tissues and promote spread of infection Spores - Dormant-latent form of bacterium - Can survive long periods of time in spore state - Highly resistant to heat and disinfectants - Use autoclave to sterilize [Viruses] - Small obligate intracellular parasites - Protein coat or capsid - Nucleic acid DNA or RNA Classification dependent on nucleic acid present Some RNA-containing viruses contain reverse transcriptase enzymes to convert RNA to DNA - Treatment: Antiviral medication, these, medications usually stop the virus from making more copies of itself Active Viral Infection - Virus attaches to host cell. - Viral genetic material enters the cell. - Viral DNA or RNA takes control of cell. - Uses host's cell to synthesize viral proteins and nucleic acids - New viruses are assembled in cytoplasm of cell. - Viruses released by lysis of host cell or by budding from host cell membrane Latent Viral Infection - Virus enters cell as with active infection. - Viral proteins are produced and Inserted into membrane of the host cell. This may stimulate an immune response and destruction of host cell. - Virus may reproduce actively if immune system is depressed (e.g., herpesviruses) Chlamydia, Rickettsiae, Mycoplasmas - Obligate intracellular parasites - Lack some basic components - Classified as bacteria - Replicate by binary fission within host cell - Chlamydia- Common cause of sexually transmitted disease - Rickettsiae- Transmitted by insect vectors (lice, ticks) - Mycoplasmas- Lack cell wall, Cause of atypical type pneumonia [Fungi] - Eukaryotic organisms (contain nucleus) - Found throughout environment On animals, plants, humans, food - Fungal or mycotic infection, From single-celled yeast or multicellular molds - Only a few are pathogenic. - Cause primary infection on skin or mucous membranes but may spread systemically particularly in immunosuppressed individual - Treatment: Antifungal, usually topical ointments but can take medication but it's hard on humans [Types of fungus (test)] Tinea pedis- Athletes foot Tinea Corporis -- Ringworm (body) Tinea Capitis -- Ring worm of scalp Tinea cruris- Jock itch (folds around the groin) Tinea Unguium -- nail Examples of Fungal Diseases - Histoplasma can cause neurologic disease and can be transmitted to embryo or fetus if mother is infected - Tinea pedis (athlete's foot) - Candida: usually harmless, but opportunistic- Causative agent of thrush and vaginitis - Pneumocystis jirovecii - Opportunistic organism causing pneumonia- Has some characteristics of fungi and some of protozoa [Protozoa] - Eukaryotic forms - Unicellular, lack cell wall - Many live independently, others are obligate parasites - Pathogens are usually parasites. - Examples of protozoal diseases: Trichomoniasis, Malaria, Amebic dysentery - Treatment: Anti-parasitic [Helminths (flatworms or roundworms)] - Are not microorganisms - Parasites - May be small or up to 1 m in length - Life cycle with at least three stages- Ovum, larva, adult - Enter body through skin or by ingestion, depending on species - Infections more commonly found in young children - Infection can be life-threatening in an immunosuppressed client. - Pinworms: ova inhaled in dust in fecally contaminated areas; common in children worldwide - Hookworms: larvae enter skin from fecally contaminated soil in tropical areas - Tapeworms: most common form transmitted by larvae in undercooked pork - Ascaris---giant roundworm: ingested with food that has been grown in feces-contaminated soil or prepared with hands that have been in feces-contaminated soil - Treatment: Anti parasitic [Prions] - Protein-like agents that change the shape of proteins within host cells - Transmitted by contaminated tissues, Ingestion of meat, Infected blood or donor organs - Cause degenerative disease of the nervous system - Human prion diseases- Creutzfeldt-Jacob disease and variant Creutzfeldt-Jacob disease ( mad cow disease), Both rapidly progressive and fatal - No treatment - Not living [Resident Flora] Many areas of the body have a resident population of mixed microorganisms termed normal flora. - Skin - Nasal cavity - Mouth - Gut - Vagina - Urethra Principles of Infection (test) - Infection---organism is able to reproduce in or on body's tissues - Sporadic In a single individual - Endemic Continuous transmission within a population - Epidemic Higher than normal transmission or spread to new geographical area - Pandemic Transmission has occurred on most continents. Transmission of Infectious Agents [Reservoir] - Source of infection - Person with active infection - Person who is asymptomatic [Carrier ] - A person may never develop the disease but still is a carrier. - A person with subclinical signs of the disease - Asymptomatic [Transmission of Infectious Agents: Links in the Infection Chain] Agent: [ ] the microbe causing the infection Reservoir: - Environmental source such as contaminated soil - Infected person or animal - Person may carry the agent and show no signs of disease - Person or animal may show signs and symptoms of disease Portal of exit: means whereby the agent leaves the reservoir Mode of transmission: method whereby the agent reaches a new susceptible host - Air - Water - Direct contact - Food Portal of entry: access to new host Susceptible host: susceptibility will depend on: - Health status - Immunity - Age - Nutrition Modes of Transmission Direct contact - No intermediary - Touching infectious lesion, sexual activity - Contact with infected blood or bodily secretions Indirect contact - Involves intermediary object or organism - Contaminated hand or food - Fomite---inanimate object Droplet transmission (heavier, up to six feet) - Respiratory or salivary secretions are expelled from infected individual Aerosol transmission (smaller, stray in air longer) - Involve small particles from the respiratory tract - Suspended in air and can travel farther than droplets Vector-borne - Insect or animal is an intermediate host [Nosocomial Infections] - Occur in healthcare facilities - Hospitals, nursing homes, physician's offices, dental offices [Factors That Decrease Host Resistance] - Age (infants and older adults) - Pregnancy - Genetic susceptibility - Immunodeficiency - Malnutrition - Chronic disease - Severe physical or emotional stress - Inflammation or trauma - Impaired inflammatory responses [Virulence and Pathogenicity] Pathogenicity - The capability of a microbe to cause disease Virulence- Degree of pathogenicity, Invasive qualities (e.g., motility or enzymes), Toxins, Adherence to tissue by pili, fimbriae, specific receptors, sites- Ability to avoid host defences [New Issues Affecting Infection and Transmission] Newly emerging diseases- Ant genetically different forms of common infections such as influenza Spread beyond normal endemic areas - Superinfections- Multidrug-resistant forms of existing diseases, TB, Staphylococcus aureus [Control of Transmission and Infection] Infection control requires two approaches: - Standard precautions are used in all settings with all clients when body fluids may be exchanged. - Specific precautions for clients diagnosed with a particular infection are used in addition to standard precautions. [Physiology of Infection] Incubation period (replication of virus) - Time between entry of organism into the body and appearance of clinical signs of disease - Vary considerably with different organisms Prodromal period (no specific signs or symptoms) - Fatigue, loss of appetite, headache - Nonspecific---"coming down with something" - More evident in some infections than others Acute period (manifestation of specific infection) - Infectious disease develops fully [Break the Cycle: Provide an Example of Each of the Actions] - locate and remove or isolate the reservoir of infection. - Identify and restrict access to contaminated food or water. - Reduce contact between infected persons and the remainder of the population. - Block portals of exit and entry. - Remove or block modes of transmission. - Reduce host susceptibility by immunizations, adequate nutrition, and access to health care [Additional Techniques to Reduce Transmission] - Adequate cleaning of surroundings and - clothing - Sterilization - Disinfectants - Antiseptics [Means of Disinfection] - Sterilization of equipment by: - Chemicals - Heat in an autoclave - NOTE: Equipment must be cleaned prior to sterilization, or it will remain contaminated! Use of chemicals: - Antiseptics are used on the skin and tissues. - Disinfectants are used on surfaces or objects [Signs and Symptoms of Infection] Local signs of inflammation - Pain, swelling, redness, warmth - If bacterial---purulent exudate - If viral---serous, clear exudate Systemic signs of inflammation -  Fever may be present. - Fatigue and weakness - Headache - Nausea [Methods of Diagnosis] Culture and staining techniques - Using specific clinical specimens - Drug sensitivity tests Blood tests - Variations in numbers of leukocytes - Leukocytosis---bacterial infection - eukopenia---viral infection - Differential count - C-reactive protein - Erythrocyte sedimentation rate (ESR) Immunological testing of body fluids - Antigen identification - Antibody titer [Classification of Antimicrobials] - Antibiotic - Drugs derived from organisms - Antimicrobial, Antibacterial, Antiviral, Antifungal - Bactericidal-Drugs destroy organism - Bacteriostatic-Decrease rate of reproduction