Local And General Effects Of Invasion By Microorganism PDF

After completing this lesson, the student should be able to:  differentiate common terminology related to infectious disease  differentiate types of infections  define the stages of infection process  define the inflammation  discuss the cardinal sign of inflammation  state the purpos...

After completing this lesson, the student should be able to:  differentiate common terminology related to infectious disease  differentiate types of infections  define the stages of infection process  define the inflammation  discuss the cardinal sign of inflammation  state the purpose of inflammation  discuss the clinical manifestation of systemic infection  Microorganism exist everywhere and most of them are harmless, and some are even beneficial in that they perform essential function in the body  Infection occurs when an organism is able to colonize and multiply within the host Asepsis  Freedom from disease-causing microorganisms Colonization  It is the process when microorganism become resident flora where they grow and multiply but do not cause disease Contamination  Presence of microorganism on the body surface or an inanimate object Infectious disease  The pathologic events that result from the invasion and multiplication of microorganisms in a host Sepsis  Presence of bacteria or other infectious organism or their toxins in the blood or in other tissue of the body Pathogen  Microorganism that are capable of causing diseases Phagocytosis  The engulfing of microorganisms and foreign particles by phagocytes Virulence  Degree to which microorganism can cause infection in the host or invade the host Definition : An invasion and multiplication in body tissue by microorganisms that cause cellular injury.  Some microorganism are normal resident flora in one part of the body, yet produce infection in another. E.g, Escherichia coli - normal inhabitant of the large intestine but a common cause of infection of the urinary tract  The process of infection begins with transmission of infectious organism  Infection may end in infectious disease, a condition that depends on the response of the host to the invader Infectious disease are classified according to their severity, duration and the extent throughout the body  Local infection ❑ It is an infection where the pathogens that invade are limited to a specific point of body and remain there, multiplying until eliminated ❑ The sign and symptom are vary depending on the system affected  Systemic infection ❑ It is a condition where pathogens spread and damage different parts of the body ❑ E.g; measles and chickenpox - the virus initially invade the upper respiratory tract and then spread to the skin causing a rash and skin vesicle An infection can be acute or chronic depending on the severity and duration of symptoms  Acute infection ❑ Appear suddenly or last a short time such as influenza  Chronic infection ❑ Occur slowly, over a long period, and may last months or years ❑ Example tuberculosis, hepatitis C, syphilis  Latent infectious disease ❑ Arises from microorganisms that remain dormant in the body for long period, but then become active (usually when the person is experiencing physical and psychological stress) ❑ E.g; the herpes virus which causes cold sores and the chickenpox virus that may re-emerge later in life causing shingles  Opportunistic infection ❑ Arises from microorganisms which are not normally pathogenic to healthy people ❑ The harmless microorganisms may become pathogenic to those whose immune system has been compromised  Primary infection  The initial infection caused by microorganisms in host  Reinfection  The subsequent infection by same organism in the same host  Secondary infection  New infection set up by the new organism in the host when resistance of the host is lowered due to pre-existing infections disease  Cross-infection  This when a patient is suffering from a disease and a new infection is set up from another host or external source  Nosocomial  Cross infection occurring in the hospital or hospital acquired infection  Subclinical  Is one where clinical symptom are not apparent. There are 4 stages:  Incubation  Prodromal  Illness  Convalescence 1. Incubation  It is the time interval between entry of an infectious agent in the host and the onset of the symptoms  At this time, the infectious agent invades the tissue and begins to multiply to produce an infection and highly contagious to others  During this period there are no sign and symptoms  Example : Common cold 1-2 days, Influenza 1- 3 days, Tetanus 2-21 days 2. Prodromal  It is the time interval from the onset of nonspecific symptoms until specific symptoms of the infectious process begin to manifest  The infectious agent continues to invade & multiply  The patient may also be infectious to others  Early signs and symptoms are present but are vague, e.g. fatigue, or malaise, mild fever 3. Illness  The illness period, or acute phase, is when sign and symptom of the disease are present, e.g. fever, muscle pains, photophobia, sore throat 4. Convalescence  As the patient’s immune response and other defense mechanisms overcome the pathogen, the person gradually regains strength and health is usually restored  Sometimes the convalescence period can be lengthy and, although the individual recover from the illness, permanent damage can be caused by destruction of tissues in the affected area. E.g. deafness may follow middle ear infection System affected Sign and symptoms Skin Inflammation: redness, pain, swelling and heat Respiratory tract Increased secretion, cough, sore throat, dyspnoea Urinary tract Dysuria, frequency, urgency, cloudy and fishy smell of urine Gastrointestinal Abdominal pain, nausea, vomiting, diarrhea, tract poor appetite Central nervous Confusion, drowsiness, stiff neck, headache, system intolerance of light (photophobia) Definition : It is a local and nonspecific defensive response of the tissues to an injurious or infectious agent.  It is an immediate response of the body to any kind of injury to its cells and tissue  The response can be induce by any mechanical, chemical or infectious disease – produce factor that injures cells of the body  Commonly, words with the suffix –itis describe an inflammatory process  Example, appendicitis – inflammation of appendix; gastritis – inflammation of the stomach Purpose:  Neutralize and destroy harmful agents  Limit their spread to other tissue in the body  Prepare the damaged tissue for repair 5 classic sign of inflammation  Pain – from tissue swelling and chemical irritation of nerve endings  Swelling – due to accumulated fluids at the site  Redness – caused by increased blood flow to the injured area  Heat – due to hyperemia (increase of blood supply)  Impaired function of the part  Definition - it is an infection in which the pathogen is distributed throughout different part of the body rather than concentrated in one area  It can be life-threatening and serious infections with other complications can result in serious tissue damage if left untreated.  Usually cause by bacteria or virus  Main characteristic of infection: Affects the bloodstream causing symptoms throughout the body Pathogen is distributed throughout the body, rather than being concentrated in one area Bacterial toxin is the major reason that leads to systemic infection  Most common e.g. of a systemic infection are cold, influenza Clinical manifestation Malaise  Common symptom  Feel tired and lack of energy  Sleep more than usual …Clinical manifestation Fever  Fever is the common sign  Lead to decrease in appetite, dehydration and headache, increase heart rate …Clinical manifestation Chills  Triggers by systemic infection  Cause shiver …Clinical manifestation Aches  Ache to the fore head and back  In extreme cases, the patient will experience the whole body ache …Clinical manifestation Nausea  Systemic infection triggers a feeling of nausea  The person reacts to certain smells by vomiting …Clinical manifestation Vomiting  It is one of the major symptoms of systemic infection  The person would have the tendency of vomiting, even after consuming regular food Antibiotic  Substances produced by the microorganisms that suppress the growth of other microorganisms and may eventually destroy them. Spectrum of activity of antibiotics Antimicrobial agent is categorized into:  Broad spectrum Depending on their activity against a range of gram-  Narrow spectrum positive and gram-negative bacteria. E.g. - Broad spectrum antibiotics are active against many gram-positive and gram-negative bacteria. Narrow-spectrum antibiotics effective only against gram-negative bacteria Mode of action  Inhibitors of cell wall synthesis,  Inhibitors of cell membrane function,  Inhibitors of protein synthesis,  Inhibitors of nucleic acid synthesis,  Inhibitors of other metabolic processes,  Only few antiviral drugs have been develop.  Antibacterial drugs are not effective against viruses.  Viruses are intracellular, in order to attack them, chemotherapy agent must enter host cells. This needs a high degree of selective toxicity.  Not many antifungal drugs.  Two well known antifungal drugs include:  Nystatin ✓ Produce during fermentation by Streptomyces noursei ✓ Antimicrobial activity is limited to yeast and fungi.  Griseofulvin ✓ Obtained from Penicillium griseofulvum ✓ Use in the treatment of many superficial fungi infection of the skin and body and also some systemic mycosis  Bacteria may acquire resistance to drugs. Factors contributing to the evolution of resistant microbial organism:  Over prescription of antibiotics  Use of inappropriate antibiotics for infecting organism  Incomplete use of antibiotics prescription as symptom subside  Harbouring and spreading of resistant organism by carriers  Increased of antibiotic in farming, thus contaminating milk and meat Ways to minimize drug resistance  Avoid indiscriminate use of antibiotics when they are no real clinical use.  Avoid use of antibiotics commonly use of generalized infections.  Using correct dose of proper antibiotic to overcome infection quickly.  Using combination of antibiotic of proven effectiveness.  Use a different antibiotic when an organism gives evidence of becoming resistance to one used initially. What is asepsis?  Freedom from disease-causing microorganisms What is infection?  An invasion and growth of microorganisms in the body tissue What is local infection?  Infection with pathogen limited in one area and multiplying until eliminated In the inflammation process, the redness and heat of an inflamed area are due to a local hyperemia caused by  vasodilation What is the type of infection where pathogen spread and damage different parts of the body?  Systemic infection What is inflammation?  Local and nonspecific defensive response of the tissues to an injurious or infectious agent What is the clinical manifestation of inflammation?  Pain, heat, redness, swelling & impaired function of the part What is the clinical manifestation of systemic infection?  Malaise, fever, chills, aches, nausea, vomiting