Viral diseases Flashcards
(97 cards)
1
Q
What is the normal body temperature range?
A
36.1 - 37.5 degree celcius
2
Q
What are the two types of thermoreceptors?
A
- Peripheral (in skin)
2. Central (in the body core)
3
Q
Give examples of central thermoreceptors
A
- Brain (hypothalamus)
- Spinal cord
- Abdominal vescera etc.
4
Q
Where does thermoregulation take place?
A
Hypothalamus
5
Q
The core temperature is usually lower and less stable? True or false
A
FALSE - the core temperature is usually higher and more stable
6
Q
The skin temperature is usually lower and less stable? True or false
A
TRUE
7
Q
When does the core temperature vary?
A
- It is lower during sleep (to aid a good night sleep as we sleep better when we are cooler)
- Higher when awake
8
Q
At what temperature are you in hyperthermia?
A
> 38.5 degree celcious
9
Q
Change in temperature is sensed by …?
A
Thermoreceptors
10
Q
What is the role of the hypothalamus?
A
- Responds to an increase in environmental temperature
- Controls core temperature of the body
- Responds to a decrease in body temperature
11
Q
Define homeostasis
A
Homeostasis is a healthy state that is maintained by the constant adjustment of biochemical and physiological pathways.
12
Q
Describe the mechanism of increasing temperature with thyroid hormones
A
- T4 is converted into T3
- T3 increases ATP production
- More ATP = increase metabolic rate = more heat
13
Q
What are the two types of thyroid hormones?
A
- Thyroxine (T4)
2. Triiodothyronine (T3)
14
Q
Hyperthyroidism leads to …?
A
Heat intolerance as too much thyroid hormones are produced
15
Q
Describe the mechanism of increasing temperature via the sympathetic nervous system
A
- Catecholamine production is activated
- Catecholamine binds to beta receptors in brown fat cells
- Brown fat (good fat) - burns calories and generates heat .
- Catecholamine also stimulates alpha one receptors which allows vasoconstriction
16
Q
What is the sympathetic nervous system usually activated by?
A
Flight or fight response
17
Q
Give 2 examples of a catecholamine
A
Epinephrine and norepinephrine
18
Q
How does shivering increase the body temperature?
A
- Skeletal muscles contract
- ATP converted into ADP
- Bonds broken = energy release > Exothermic reaction
19
Q
During hyperthermia, the anterior hypothalamus stimulates …. (1)… which activates the …. (2).
A
- Sympathetic cholinergic fibres
2. Sweat glands
20
Q
How does sweat reduced body temperature?
A
- Sweat on skin evaporates from skin
2. Liquid changes to a gaseous state.
21
Q
Another way the hypothalamus reduces body temperature is by…. ?
A
- Vasodilation - more warm blood from core taken to skin surface
- Warmth is lost by radiation, convection, conduction
22
Q
What is heat exhaustion and what does it lead to?
A
- caused by high temperatures
- can lead to rapid heart beat , dizziness and fainting
23
Q
What is heat stroke and what does it lead to?
A
- occurs when body temperature is > 40 degrees celcius > causes excessive vasodilation
- can lead to confusion, coma and seizures
24
Q
When does malignant hyperthermia occur?
A
When heat dissipating mechanism are unable to keep pace with the high heat production
25
Who is more susceptible to heat strokes and why?
1. Infants and children - higher metabolic rate
| 2. Elderly - pre existing conditions e,g physical and psychological limitations
26
What are some medications for heat strokes?
1. Beta blockers
| 2. Diuretics
27
What are some risk factors for hypothermia?
1. Prolonged cold expose
2. Impaired thermoregulation
3. Heat loss
4. Cold IV fluids
28
Describe the pathophysiology of fever
1. Fever releases pyrogens e.g IL-1 and TNF
2. IL-1 signals hypothalamus to increase prostaglandin levels
3. Prostaglandins increase the set temperature in the hypothalamus
4. Heat production increases until core temperature reaches new regulated level.
29
What are the benefits of a high temperature during fever?
1. Increased rate of immune response
| 2. Compromises growth of microorganisms
30
How does aspirin reduce a fever?
It blocks the synthesis pathway of prostaglandins
31
What is pyrexia and what is is usually caused by?
FEVER, caused by infections, autoimmune diseases etc.
32
Why do we shiver during fevers?
Because there is a difference between the new set temperature and the actual body temperature - so it makes you feel cold (increases heat)
33
Define herd immunity
Resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals as a result of previous infection or vaccination.
34
What are vaccinations?
Active process of developing immunity - results in adaptive immunity
35
What are the different ways vaccines can be administered?
1. Intramuscularly
2. Intradermally (into dermis under skin)
3. Subcutaneously (into fat layer under skin)
4. Orally
36
What is adaptive immunity?
It is when you produce Memory T and B cells - when infection occurs cells can quickly proliferate and respond
37
Vaccinations help establish ..... ?
Herd immunity
38
What is passive immunity?
When a person gets antibodies made by someone else e.g from breastfeeding/cells in the lab /invitros
39
How long does passive immunity last for?
- As long as the antibodies last for
40
When is a vaccine considered successful?
When it results in a strong antigen specific titer (measures presence and amount of antibodies in blood)
41
Describe the mechanism of vaccines
1. CD4+ helper T-cells produces TNF - alpha, IFN-g and IL -2
2. CD4+ helper T-cell stimulate activated B- cells
3. Activated B cells differentiate into plasma cells >IgG, IgA, IgE
42
What are the main types of vaccines?
1. Live attenuated - whole cell vaccine
2. Inactivated - whole cell vaccine
3. Subunit - fractionated vaccine (only part of pathogen is used)
4. Toxoid - fractionated vaccine
43
What are inactivated vaccine s and what do they protect against.
- Pathogen has been killed with heat/formalin
- humoral/antibody response (plasma cells make antibodies not T-cells)
- no cellular immunity
- not as strong as live vaccine (requires boosters)
- protect against hepatitis A, Polio, Rabies and Influenza
44
What are subunit vaccines?
- contains portions of pathogens (polysaccharides or proteins)
- usually proteins of different pathogens are attached together - forms conjugate subunit vaccines
45
Why are polysaccharide vaccines not effective in kids <2 years old?
Because when T cells help is available, vaccines work better - immune system is still immature and developing
- without T cells, memory B cells cannot be formed
46
What does polysaccharide vaccines protect against?
- Haemophilus influenza Type B
- Hepatitis B
- HPV
- Pertussis
- Meningitis
- Pneumonia
47
What are toxoid vaccines?
- vaccines specifically against toxins e.g tetanus and diphtheria toxin
- usually combined with other subunit vaccines
48
What are some vaccines contraindications?
1. Patient should be healthy
2. Should not have any previous allergic reactions to past vaccines
3. Should not be used on individuals with weakened immune system
49
List 5 notifiable diseases
- Cholera
- Covid 19
- Pertussis
- Diphtheria
- Food poisoning
- Leprosy
- Malaria
- Measles
- Mumps
- Acute meningitis
- Tetanus
- Tuberculosis
- Rubella
- Yellow fever (virus spread through mosquito bites)
50
To support the reporting of the required infectious disease the Public Health England has developed... ?
The second generation surveillance system - national surveillance system that hold all the test results
51
What kind of information needs to be acquired when filling out the form to notify the PHE?
- First name and surname
- Date of birth
- Gender
- Postcode
- Contact information
- Ethnicity
- Sample taken date
- Sample number
- Sample type
- Test method e.g PCR
- Result
- Result date
- Name of laboratory
52
What is the process of reporting a notifiable disease?
1. Complete the notification form immediately on diagnosis of suspected notifiable disease (don't wait for laboratory confirmation)
2. Consult the PHE notifiable diseases poster
3. Send the form within 3 days or notify verbally within 24hours is case is urgent
53
What are the 4 common viral infections seen in primary care?
1. Influenza
2. Human papilloma virus
3. Herpes viruses
4. Viral rashes
54
Name 3 common respiratory viral infections
- Adenovirus
- Influenza A and Influenza B
- Parainfluenza
- Rhinovirus
- Coronavirus
55
How many people did the pandemic influenza infect?
50 Million worldwide
56
What are some risk factors for complicated influenza?
- Neurological, hepatic, renal, pulmonary and chronic cardiac disease
- Diabetes mellitus
- Severe immunosuppression
- Age over 65 years
- Pregnancy
- Children under 6 months
57
Who are usually first immunised with influenza?
- Primary school children (super spreaders)
- Healthcare workers and carers
- Elderly
58
Human Papilloma virus cases a range of human disease? True or false?
TRUE
59
What is a serotype?
A serologically and antigenically distinct variety of microorganism
60
What can high risk serotypes of HPV cause?
Malignancy
- Cervical cancer
- Head and neck cancer
- Penile cancer
- Anal cancer
- Vaginal cancer (rare)
61
What is common in HPV?
Hnad and foot warts
62
What vaccine protects against 4 serotypes of HPV?
Gardasil
63
What viruses are part of the human herpes viruses?
- Herpes Simplex Type 1 and 2
- Cytomegalovirus
- Chicken pox and shingles
- Epstein Barr Virus
- Human herpes virus types 6, 6A, 7 and 8
64
Once you get infected with a HHV virus, you recover and do not keep it for life. True or False?
FALSE
| - you keep it for life usually in a dormant form
65
In what HHV does reactivation occur?
- Shingles
| - Pityriasis rosea in HHV 6 and 7
66
What is the cytomegalovirus?
A genus of viruses in the order herpesvirales
| - humans and monkeys serve as natural hosts
67
Cytomegalovirus causes an infection similar to?
- EBV but less pharyngitis or tonsillitis)
68
Where does a serious infection of cytomegalovirus occur?
In the immunocompromised
69
FACT
70% of sore throats are caused by viral infections including EBV
70
What does Epstein - Barr virus cause?
- Glandular fever
| - Initial infection of oral epithelial cells with subsequent spread to B lymphocytes
71
What kind of diseases do Epstein - Barr viruses cause?
- Infectious mononucleosis - acute infections characterized by fever, fatigue, leucocytosis
- Burkitt lymphoma - undifferentiated B lymphoma of the jaw
- Nasopharyngeal carcinoma - proliferation of EBV - infected epithelial cells in nasopharynx
- Central nervous system lymphoma
Lymphoma = white blood cell cancer - leucocytes grow out of control
Leucocytosis = increase in leukocytes
72
Human herpes virus type 6 can be isolated from the saliva of about ..... % of adults
85%
73
HHV type 6 causes what in children?
Roseola infantum - causes high fever and rash
74
What is the % risk of a healthcare facility in the developed world developing an infection
10%
75
What are nosocomial bacterial infections?
Infections caused by organisms that are resistant to numerous antibotics e.g MRSA
76
What are some Infection Prevention Control Measures in Institutions
- Specialised ventilation (laminar flow)
- Cleanliness of environment and medical equipment
- Handling, storage and disposal of clinical waste
77
Give examples of IPC measures for healthcare staff
- Education
- Hand hygiene
- Use of PPE
78
Name 2 airbone infections
Measles and TB
79
Name two droplet infections
Norovirus
C. difficile
Rota virus
MRSA
80
Name 2 direct contact infections
```
Influenza
Rubella
Plague
Pertussis
Diphtheria
Parvovirus
```
81
Name 3 prevention and control measures of communicable diseases
1. Immunisation
2. Interruption of infection transmission e.g quarantine, good hygiene etc.
3. Rapid diagnosis and treatment of infected individuals
82
What is a needle stick injury?
An incident in which the blood of a patient comes into contact with the blood of a healthcare worker
83
What are the three types of exposure in health care settings associated with significant risk from blood or higher risk body fluids
1. When a needle or sharp object breaks the skin
2. Exposure of broken skin
3. Exposure of mucous membranes (+ eyes and mouth)
84
What are blood borne viruses?
Viruses which can be present in blood or other body fluids - high potential for transmission to another person
85
Examples of blood borne viruses
Hepatitis B (HBV)
Hepatitis C (HCV)
HIV
- ranked in the order of most infectious
86
What is the transmission rate for HBV
30%
87
What is the transmission rate for HCV
3%
88
What is the transmission rate for HIV
0.3%
89
What is a post exposure prophylaxis (PEP)
Treatment that might be advised to recipient following a risk assessment form a known or high risk HIV or Hepatitis B exposure incident
90
Name 3 infectious fluids could be transmitted during a needlestick injury?
- Blood
- Amniotic fluid
- Vaginal secretions
- Semen
- Breast milk
- Cerebrospinal fluid
- Peritoneal fluid
91
Name 2 non - infectious fluids
- Urine
- Vomit
-Saliva
- Faeces
(if not visibly blood stained)
92
Describe the immediate management of a needlestick injury
- Bleed, wash and cover
| - Inform person in charge of ward/department
93
What should you do if you had a needle stick injury with high risk of HIV
- Attend A&E for assessment with the details of the 'source'
94
What should you do after the immediate management of a needle stick injury -
- Contact workplace health and wellbeing
| - Contact site nurse from operation centre to assess whether A&E assessment is needed
95
What happens to the source of a needle stick injury
1. Gain consent for blood test
| 2. Arrange for blood test of HIV serology, Hepatitis B surface antigen, Hepatitis C antibodies
96
What is the heat conservative centre in the hypothalamus?
Posterior hypothalamic nuclei
97
What is the heat loss centre in the hypothalamus?
Preoptic and anterior nuclei
