Week 118 - Pyrexial Illness Flashcards Preview

Revision Cards > Week 118 - Pyrexial Illness > Flashcards

Flashcards in Week 118 - Pyrexial Illness Deck (38):
1

There are four patterns of fever, what are they?

1) Intermittent Fever- One in which the temperature returns to normal at least every 24 hours.

2) Remittent Fever- The temperature does not return to normal but fluctuates by a couple of degrees in either direction.

3) Sustained Fever - Remains above normal with only minimal variation.

4) Relapsing Fever - Periods of a couple of days when temperature is normal, followed by periods of fever.

2

What is the relationship between heart rate and temperature?

An elevation of 1˚C results in an increase of 15bpm.

3

What is the physiology of thermoregulation?

• The Hypothalamus is the body's thermostat.
- Heat sensitive receptors are located in the preoptic area in the anterior part of the hypothalamus.
- An increased temperature (Above 37.1) causes increased signal output whilst a decreased temperature causes a decreased signal output.
With elevations in core temperature the sympathetic nervous system is inhibited leading to vasodilation of skin vessels and stimulation of sweat glands to reduce temperature.

evaporative heat loss until body temp matches set point 

 

4

There are four stages of a fever, what are they?

1) Prodromal phase.

2) Chill stage.

3) Flush Stage.

4) Defervescence.

5

What occurs during the Prodromal phase of a fever?

Non-specific complaints such as malaise, headaches, fatigue and aches.

6

What occurs during the chill stage of a fever?

There is an uncomfortable feeling of being cold, and shivering sets in. It is normally precipitated by vasoconstriction and piloerection. When shivering causes the body reach the new set-point a sensation of warmth develops.

7

What occurs during the flush stage of a fever?

Vasodilation occurs, causing the individual to feel warm and look flushed.

8

What marks the defervescence stage of a fever?

The onset of sweating.

9

What is the most studied exogenous pyrogen and where does it come from?

Lipopolysaccharide, it is derived from the cell walls of gram-ve cell walls.

10

What is the mechanism of fever?

• Exogenous or endogenous pyrogens bind to TLRs on monocytes and dendritic cells.
- This stimulates the formation of pyrogenic cytokines such as IL-1,-2 & -12, TNF-alpha and INF.
- These cytokines act on the thermoregulatory centre causing an increase in the prostaglandin, PGE2, which modifies the responsiveness of thermosensitive neurones.

11

Which two substances are endogenous antipyretics?

• IL-10 and glucocorticoids.

• They compete with IL-6.

12

How do NSAIDS and aspirin, reduce fever?

They both inhibit the production of PGE2.

•NSAIDS - Inhibits the activity of COX2, which enables the production of PGE2.

•Aspirin (and other salicylates) - As above but irreversibly inhibits COX2.

13

Provide some evidence as to why fever may be beneficial.

• It is widespread among animals, would not be preserved by evolution if it was not beneficial.

• IL-1 (an endogenous pyrogen) is critical for the initiation of the immune response.

• Small elevations in temperature (such as those in fever) aid the function of some immune responses.

• Many microbes function best at normal body temperature.

• Raised body temp. inhibits growth of bacteria and viruses.

14

How does Hyperthermia differ from fever?

Hyperthermia is an increase in body temperature without a change to the thermoregulatory set-point. Therefore, antipyretics are of no use.

15

What is the definition of Pyrexia of Unkown Origin?

A consistently increased temperature above 38.3˚C for three weeks, with no diagnosis after three days as an inpatient or 3 outpatient consultations.

16

What are the main causes of PUO?

• Infection - 30%

• Malignancy - 20%

• Connective Tissue Disorders - 15%

• Misc. - 20%

• No diagnosis or spontaneous recovery - 15%

17

 

What type of cell is this? What is it's function?

Q image thumb

Monocyte - Macrophage (In tissue)

• Recruited to sites of infection, very numerous in sites of infection.

• Mononuclear-phagocytic system.

• First contact with foreign antigen, initiate immune response through cytokines.

18

What type of cell is this? What cell line is it derived from? What is its function?

Q image thumb

Neutrophil

• Polymorphonuclear leukocyte

• From the bone morrow, myeloid stem cells.

• Granules contain enzymes, responds to chemoattractants, phagocytic.

19

What type of cell is this? What cell line is it derived from? What is its function?

Q image thumb

Basophil/ Mast cell(In tissue)

• Polymorphonuclear leukocyte.

• Myeloid stem cells.

• Contain histamine, have Fc receptors for IgE, important role in hypersensitivity / anaphylaxis.

 

20

What type of cell is this? What cell line is it derived from? What is its function?

Q image thumb

Eosinophil

• Polymorphonuclear Leukocyte.

• Myeloid stem cell line.

• Produces histaminase and has an important role against helminths.

21

What are Lymphocytes?

These are immune cells that develop in the bone marrow and the thymus.

B-Cells, T-Cells are an important part of adaptive immunity.

NK-Cells are an important part of innate immunity.

22

What cells are derived from the lymphoid cell line?

• B-Cell, T-Cell, NK-Cell, Plasma Cells.

23

Malignant proliferation of Lymphocytes leads to what?

Lymphoma or Leukaemia.

24

What does malignant proliferation of plasma cells lead to?

Multiple Myeloma.

25

What are platelets derived from?

Myeloid Stem Cell - Megakaryoblast - Megacaryocyte - Platelet

26

What are the four stages of Pharmacokinetics?

1) Absorption

2) Distribution

3) Metabolism

4) Excretion

27

What does 'enteral' mean in terms of drug administration?

By way of the intestine, i.e. oral or rectal.

28

What are the advantages and disadvantages of enteral administration of medication?

• Advantages
- Easy access.
- Can recover drugs easily.
- Can be delivered in the community.

• Disadvantages
- Greatest level of variability
- Some cannot cross GIT membrane.
- 1st pass metabolism.
- Cannot always see that drug is taken.

29

What are some of the advantages and disadvantages of parenteral administration?

• Advantages-
Rapid entry.
- Good control of dose.
- Avoids 1st pass metabolism.
- Can be seen to be given.

• Disadvantages-
- Risk of infection.
- Cannot recover drugs.
- Patients do not like big needles.

30

What is the speed of action of certain drug administration routes?

• Inhalation - 5-60secs.
• I.V. - <60secs.
• I.M., S.C., intrathecal, sublingual. - Several minutes.
• Rectal - 15-30mins.
• Oral, transdermal - 30-60mins.
• Topical - Within 1hr.

31

What is a simple febrile convulsion?

• A tonic-clonic seizure.
• Does not last longer than 15 mins.
• Does not reoccur within 24hrs.
• Low risk of subsequent epilepsy.

32

What is a complex febrile convulsion?

• The seizure lasts longer than 15mins.
• Child has another seizure within 24hrs.
• Symptoms in only one part of the body - known as a partial or focal seizure.
• Does not recover fully within 1hr.

33

What is the typical clinical picture of a urinary tract infection? 

Polyuria, dysuria, fever, haematuria, lower abdominal pain.

34

What is the typical clinical picture of infective endocarditis?

Heart murmur, fever, night sweats, weightloss, myalgia and arthralgia.

35

What is the typical clinical picture of Septicaemia?

High fever, rigors, hypotension, myalgia and headache.

36

What is the typical clinical picture of Pneumonia?

Cough productive of sputum, fever and breathlessness.

37

What is the typical clinical picture of Menningitis?

Fever, stiff neck, headache, petechial or haemorrhagic rash.

38