Infectious Disease Intro PT1 Flashcards
Characteristics of the immune system
- Protects body from pathogens
- Can be specific
- Has memory
- Mobile and fast acting
Is flexible
What is the initial defence of the immune system
a) Non specific defences
- Physical barriers
- Chemical barriers (stomach acid)
- mucus and cilia protect our respiratory tract
- Urine flushes out bacteria from urinary tract
- Enzymes are in tears and saliva
- Other bacteria is present on our skin/ in our digestive tract
What happens if the initial defences of the body fail or weaken
Infection becomes more likely
What are non specific defences part of
Innate immune system
What cells are within the innate immune system
- Macrophages and monocytes: antigen presenting cells and surveillance
- Neutrophils: defence against bacteria and fungus
- Eosinophils: defence against parasites and respond to allergies
- Basophils: respond to allergens
- Mast cells: inflammatory mediators
- Complements: can lyse pathogens, coat pathogens and can call for backup
- Chemokines: act as traffic controllers for WBCs
What does the adaptive immune system involve
- T and B lymphocytes
Macrophages and monocytes
antigen presenting cells and surveillance
Neutrophils
defence against bacteria and fungus
Eosinophils
defence against parasites and respond to allergies
Basophils
respond to allergens
Mast cells
inflammatory mediators
Complements
can lyse pathogens, coat pathogens and can call for backup
Chemokines
act as traffic controllers for WBCs
Chemokines
act as traffic controllers for WBCs
What are the two parts of the adaptive immune system
- Humoral mediated: within the serum
- Cellular mediated: within the cells
How much antigens can lymphocytes remember
10 to the power of 15
Characteristics of T lymphocytes
- Activated by antigen presenting cell
- The activated T cells secrete IL-2 which stimulates the production of more activated T cells
What can are the different activated T cells
- Helper cells (CD4+): secrete Ils and interferon, stimulates CD8+ cells and stimulates production of antibodies
- Cytotoxic cells (CD8+): kill cells recognized as foreign
- Regulating cell: regulates the T cell response
Characteristics of B lymphocytes
- Are activated after they recognize antigens (through T- lymphocytes usually)
- The antibodies of the B lymphocytes bind to antigens and either trap the antigens or clump them together/ increase the attack of immune cells
What can activated B cells become
- Plasma cells: secrete antibodies
- Memory cells: important in future attacks (remember antigens)
What are cytokines
- IL,TNF, IFN..
- Soluble factors secreted by cells
- Can activate cells, call for backup…
What are inflammatory mediators
- Soluble factors that causes inflammation
- Can be secreted by many cells
- Ex. Histamine, PGs…
What is an infection
- Get a response of a hosts immune systems and person gets ill
What is a sub clinical infection
- Specific response in the body occurs but person is not ill
What is colonization
- Presence of an organism at a body site without production of disease
- Do not treat
What is pneumonia an example of
- Infection
What is influenza, EBV, SARS-CoV-2 and example of
- Sub clinical infection
What is skin wounds colonized with staph and example of
Colonization
What is another name for EBV (Epstein Barr virus)
Mono
What causes invasion of microorganisms
- Breach of host defenses
What are toxins
- Some bacteria produce toxins which can damage cells
- Can even damage at distant sites
- Examples are botulism or tetanus
For tetanus what would you give first to treat
- An anti toxin before and antibiotic
What is the normal microbiota in the skin
- Diphtheroid (ex. Corynebacterium)
- Propionibacterium
- Staphylococci (mostly coagulase negative strains)
- Streptococci
What is the normal microbiota in the gastrointestinal tract
- Bacteroides sp
- Clostridium sp
- Diphtheroid
- Enterobacteriaceae (ex. E. coli, klebsiella sp)
- Fusobacterium sp
- Streptococci (anaerobic)
What is the normal microbiota in the genital tract
- Corynebacterium sp
- Enterobacteriaceae sp
- Lactobacillus sp
- Mycoplasma sp
- Staphylococci
Streptococci
what does the host defense involve
- Both innate/ adaptive parts of the immune system
Both prevents and cures infection
Do antibiotics cure infection
Not always
What other things other then antibiotics may an infection need in order to be cured
- Drainage of abscess
- Removal of dead tissue (doesn’t have a blood supply so antibiotics cant get to the target
- Removal of foreign bodies or prosthetic devices (don’t have blood supply and produce a biofilm)
- Decrease in immune suppression (Immunosuppression is used during organ transplant in order for the body to not reject the transplant)
What are factors that affect host defenses
- Malnutrition (WBCs don’t function properly)
- Age
- Immune globulin deficiencies
- Deficiencies in cellular immunity
- Alcoholism
- Diabetes
- Immunosuppressive therapy (ex. Anti cancer/ corticosteroids)
- Invasive procedures (break normal barriers)
What are non specific symptoms of infection
- Malaise (discomfort)
- Listlessness
- Loss of appetite
- Headache
- Myalgias (muscle aches
- Arthralgias (joint aches)
- Fever
- White blood cell counts
- Anemia
- Increased ESR and CRP
- Increased procalcitonin (PCT)
- Increased heart rate
- Anxiety
- Confusion
- Septic shock
Characteristics of fever within infection
- It is due to infection unless proven otherwise
- Temp cycles throughout the day (highest in late afternoon and lowest 12 hours later
In this class a fever is anything greater then what
- 37.2C at 6am
- 37.7C at 4 pl
- 38.2C rectally
- 37.2C armpit
What does an uncontrolled fever mean
- If temp continues to go up
What is normal/infectious WBC count
- Normal: 5-10 x 10power9 /L
- Infection is anything over this (when there is an infection WBC count increases )
When else can WBC counts change
- Can be higher in patients with leukemia and RA in patients taking lithium/ corticosteroids
- Increase may be mild in less severe infection or in elderly
What are the percentages of WBC subpopulations and when do they rise
a) Total neutrophils: 50-70%
- Segmented neutrophils (mature): 50-70%
- Bands (immature neutrophils): 50-70%/ if high then most likely an infection as the body is working more
- Lymphocytes: 20-40%/ HIV uncontrolled lowers lymphocytes - Monocytes: 0-7% - Eosinophils: 0-5%/ rise when parasitic infections or allergies present - Basophils: 0-1%
What are the different types of neutrophils
- Broken into shape of nucleus
a) Segmented- A mature
- Nucleus is segmented
b) Band - Immature
- Nucleus is smooth and parallel
When is anemia present
- May be present mainly with chronic infection
what do erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) mean
- Markers of inflammation
- May be used as a monitoring tool for infections such as endocarditis/ osteomyelitis
Explain septic shock (characteristics and presentation)
- A malfunction in many body systems
- Decreased BP and CO
- Decrease in renal function
- Hepatic dysfunction (increased bilirubin)
- Decreased oxygenation
- Dissemination intravascular coagulation (DIC)
Can antibiotics treat septic shock
- No they cant
- This is why the faster an infection is treated the better
