U4

Question 1

PRION

Answer 1

Prions: Protein molecule – mutated form causes brain disease in humans and animals [remember “mad cow disease”?]. Can incubate for decades before s/s appear. S/s of brain damage. No cure currently.

Question 2

VIRUS

Answer 2

Virus: Requires a host cell (often bacteria) to inject its “viron” particle into the host cell which then triggers the host cell’s DNA or RNA to replicate a virus. “Needs a HOST to replicate and survive.”

Question 3

BACTERIA

Answer 3

Bacteria: Single cell organisms classified as either- “Reproduces independently – does NOT need a host.”
Gram Positive: Exotoxin producing – releases a toxin while alive and reproducing.
Gram Negative: Endotoxin producing – does not release its toxin until the bacteria dies (as it does when a person is on antibiotic medication). High levels of endotoxin can trigger septic shock, DIC, and ARDS.

Question 4

CHLAMYDIA & RICKETTSIA

Answer 4

Chlamydia & Rickettsia: “Reproduce independently like bacteria, but need a host cell for energy, like viruses.”
~ Chlamydia is a sexually transmitted disease (to be discussed in Unit 12)
~ Rickettsia (carried by ticks and lice) causes Rocky Mountain Spotted Fever.

Question 5

FUNGAL PATHOGENS

Answer 5

Fungal pathogens: Transmitted by spores (molds and yeast). The cause of many “opportunistic” infections in an immunocompromised host. Example: People with AIDS or on chemotherapy are prone to get oral “thrush” and other yeast or fungal infections. Women taking antibiotics can develop a vaginal overgrowth of candida albicans. See Pg. 304 of text for an explanation how this occurs.

Question 6

PROTOZOAL PATHOGEN

Answer 6

Protozoal pathogens: Protozoa are parasitic animals that infect or colonize other animals, which then transmit them to humans. In some cases, the directly infect the human host. Parasites can be transmitted by food/water, feces, or insects (worms or ticks/fleas/lice).

Question 7

DISCUSS THE STAGES OF INFECTIOUS DISEASE

Answer 7

Incubation: NO S/S. The number of pathogens in the body have NOT reached a large enough number to cause symptoms

Prodrome or Prodromal: First onset of signs and symptoms of an infection

Acute: Phase of maximum effect (damage) to the body. Can be further delineated by the “Invasive” and “Decline” phases of Acute Infection.

Resolution or Convalescence: The body’s defenses begin to overcome the pathogen and signs and symptoms decrease.

Question 8

SIGN VS SYMPTOM

Answer 8

SIGN: Objective information regarding an illness. Can be seen/felt/heard/smelled by another person and/or “measured”. Examples: Temperature, weight, the condition of a wound, the character of the pulse, breath sounds heard through a stethoscope, etc.

SYMPTOM: Subjective information regarding an illness. Cannot be seen/felt/heard/smelled by another person, or measured with objectives instruments. Pain is always a subjective finding because the patient is the only one to experience it.

Question 9

EPIDEMIOLOGY

Answer 9

Epidemiology: the study of health in populations to understand the causes and patterns of health and illness. Epidemiology is the scientific method used by “disease detectives”—epidemiologists—to get to the root of a public health problem or emerging public health event affecting a specific population.

Question 10

VECTOR

Answer 10

Vector: Arthropods (insects or arachnids) that transmit pathogens to humans. The arthropods that most commonly serve as vectors include: 1.) blood sucking insects such as mosquitoes, fleas, lice, biting flies and bugs, and 2.) blood sucking arachnids such as mites and ticks. The term “vector” refers to any arthropod that transmits a disease through feeding activity. Vectors typically become infected by a disease agent while feeding on infected vertebrates (e.g., birds, rodents, other larger animals, or humans), and then pass on the microbe to a susceptible person or other animal.

Question 11

RESERVOIR

Answer 11

Reservoir: Carriers of the disease (i.e., animals infected with rabies can pass on the pathogen). The reservoir of an infectious agent is the habitat in which the agent normally lives, grows, and multiplies. Reservoirs include humans, animals, and the environment. The reservoir may or may not be the source from which an agent is transferred to a host. For example, the reservoir of Clostridium botulinum is soil, but the source of most botulism infections is improperly canned food containing C. botulinum spores.

THERE ARE HUMAN, ANIMAL AND ENVIRONMENTAL RESERVOIRS

Question 12

FOMITES

Answer 12

Fomites: Inanimate objects that pathogens live on (door knobs, bedding, drinking glass, stair railing, etc.)

Question 13

MORBIDITY

Answer 13

Morbidity is an incidence of ill health. It is measured in various ways, often by the probability that a randomly selected individual in a population at some date and location would become seriously ill in some period of time.

Question 14

MORTALITY

Answer 14

Mortality is the incidence of death in a population. It is measured in various ways, often by the probability that a randomly selected individual in a population at some date and location would die in some period of time.

Question 15

COMORBIDITY

Answer 15

Comorbidity - The simultaneous presence of 2+ morbid conditions or diseases in the same Pt, which may complicate a Pt’s hospital stay; Example: A person with heart failure could have a “comorbidity” of diabetes that will have to be treated also. The presence of comorbidity could make the primary condition harder to treat/heal.

Question 16

AIRBORNE PRECAUTIONS

Answer 16

AIRBORNE PRECAUTIONS – “You’re On-The-Air with MTV”
Small airborne particles can travel several feet, especially if propelled by a cough or a sneeze.
Precautions: Private Room - negative pressure with 6-12 air exchanges/hour. Hepa/N95 mask per agency policy.

M- measles (Rubeola) (“It’s all about ME on MTV” to remember that this “m” is measles and not meningitis or mumps).
TB - tuberculosis (Patient must wear an N95 mask when in public areas of hospital. Care provider needs N95 mask)
Varicella - Chicken Pox (also use contact precautions)

Question 17

DROPLET PRECAUTIONS

Answer 17

DROPLET PRECAUTIONS - “MR. PIMP drops off his pro’s”
Larger droplet particles do not travel as far as airborne particles – about three feet from the source. Many
droplet pathogens require CONTACT as well as DROPLET precautions.
Precautions: Private Room or cohort Mask. Gown/gloves/eye protection as needed

M – Meningitis (”most MEN are pimps” to remember that this “m” is meningitis, not measles or mumps)
R – Rubella (GERMAN measles)

P – Pertussis (whooping cough)
I - Influenza
M - Mumps
P – Pneumonia

Question 18

CONTACT PRECAUTIONS

Answer 18

CONTACT PRECAUTIONS - MRS.WEE Precautions: Use gown, gloves, shoe/hair covers as needed

M - multidrug resistant organism (MDRO)
R - respiratory infection
S - skin infections
W - wound infection
E - enteric infection - clostridium difficile
E - eye infection – conjunctivitis [pink eye]

Question 19

VACCINES

Answer 19

Vaccines – Are either Attenuated live vaccine or killed viruses. The purpose of receiving a vaccine is to trigger the body to produce antibodies against the virus. Examples: Measles, Mumps, Rubella (MMR) vaccine.

Question 20

TOXOIDS

Answer 20

Toxoids – Tetanus, Pertussis and Diphtheria shots are an example.

DPT ARE BACTERIA NOT VIRUS

Question 21

HYPERSENSITIVITY

Answer 21

Hypersensitivity disorders occur when an antigen enters the body and the immune system OVER-REACTS to it. Reactions can be delayed or immediate.

Question 22

There are four types of reactions REGARDING HYPERSENTIVITY

Answer 22

ACID
Anaphylactic/Allergic: TYPE I
2. Cytotoxic: TYPE II
3. Immune complex disease: TYPE III
4. Delayed hypersensitivity (cell mediated): TYPE IV

Question 23

Anaphylactic/Allergic: TYPE I

Answer 23

Mast Cells (in the tissue) release numerous chemical mediators such as histamines, cytokines, prostaglandins and kinins (bradykinin) that cause the symptoms of Anaphylactic shock:
Laryngeal edema causing airway obstruction [an AIRWAY problem].
Smooth muscle contraction → constricted airways so lungs are unable to take in air [a BREATHING problem].
Vasodilation → hypovolemia or low blood volume that in turn causes hypotension (low blood pressure).  Low B/P prevents major organs from getting blood which leads to shock [a CIRCULATION problem].
Vomiting [a CIRCULATION problem] and abdominal cramping.

A severe allergic reactions can cause death in 6 minutes (Anaphylactic SHOCK) because the blood flow to the brain and vital organs is decreased to the point that the organs begin to die from lack of oxygen.

Eosinophils (in the blood) are leukocytes that are responsible for the late response.

EXAMPLES of Type I hypersensitivity are Asthma, bee stings in sensitized individuals, pollen exposure, or food allergies. Reactions can range from mild itching, runny nose to anaphylactic shock and death.

Question 24

Cytotoxic: TYPE II

Answer 24

Antibody-mediated response to an antigen on a cell surface. When the antibody attacks the antigen, it also kills the cell to which it is attached (thus the name “CYTOtoxic”). A primary example of TYPE II hypersensitivity is blood incompatibilities, and when a RH-negative mother develops antibodies against her RH-positive baby’s blood. The mom’s antibodies then attack the baby’s blood cells because they have RH factor coating.

Question 25

Immune complex disease: TYPE III

Answer 25

When an antibody binds to an antigen it can make a complex that the body cannot absorb. These complexes then trigger the inflammatory response. These complexes cause damage to organs and blood vessels causing kidney damage or vasculitis. Immune complexes also play a damaging role in Lupus as well as glomerulonephritis.

Question 26

Delayed hypersensitivity (cell mediated): TYPE IV

Answer 26

Cell-mediated rather than antibody-mediated. These T cell lymphocytes attack some types of viruses and microbes. They are also triggered in contact dermatitis (like poison ivy antigens). Called “delayed-hypersensitivity” because it takes 24 to 72 hours for symptoms to show.

Question 27

Define AUTOIMMUNE DISEASES

Answer 27

Define AUTOIMMUNE DISEASES: Body is unable to distinguish self from foreign. Cells of the immune system attack various parts of the body depending on the type of AI disease involved. AI diseases are INCURRABLE.

Rheumatoid arthritis (RA) most common – 1% of world population
Type 1 Diabetes
Inflammatory Bowel Disease and Crohns Disease
Lupus (systemic lupus erythematosus –SLE)
Psoriasis

Question 28

just read:

Mechanisms of autoimmune disease

Answer 28

MECHANISMS of AUTOIMMUNE DISEASE:

The body makes antibodies against itself – does not recognize some tissues as belonging to the body.
Genetic predisposition is common (runs in families)
Triggered by: Chemical / biologic substances (i.e., viruses, bacterial infection), Abnormal immune cells.
More common in women (3:1) especially of childbearing age (16 to 35 years of age).
All ages affected.

Question 29

Tx FOR AUTOIMMUNE DISORDERS

Answer 29

Treatment for Autoimmune Disorders:

    Depends on area of the body affected, but often includes immunosuppression drugs (also used to treat cancer) such as steroids and Methotrexate; and Monoclonal Antibodies (drug names end in “-mab” which is  a handy way to remember that anyone taking these drugs “must-avoid-bugs” or germs, because they are immunocompromised).  

     MABs are the designer drugs of the future because they can target specific cell types (such as cancer cells) without damaging surrounding tissue as traditional chemotherapy does.