118 - Pyrexial Illness Flashcards Preview

Year 1 > 118 - Pyrexial Illness > Flashcards

Flashcards in 118 - Pyrexial Illness Deck (47):
1

Which drugs can cause neuroleptic malignant hyperthermia?

  • Haloperidol
  • Chlorpromazine

They block the dopamine receptors in the basal ganglia and hypothalamus.

1

What bacteria adhere to the surface of the intestinal epithelium?

  • E. coli
  • Salmonella enterica serovar Typhimurium
  • Vibrio cholerae

2

What happens if the body temperature falls below the set-point?

  • The sympathetic nervous system is activated leading to vasoconstriction and inhibition of sweating
  • Endocrine changes
  • Behavioural changes; huddling or putting more clothes on

3

What are the 4 stages of fever?What characterises each?

  1. Prodronal; general unwell feeling, malaise, headaches, fatigue and aching
  2. Chill; uncomfortable sensation of cold leading to shivering, vasoconstriction and piloerection until new setpoint reached
  3. Flush; cutaneous vasodilation and feeling of warmth
  4. Defervescence; initiation of sweating.

3

Which drugs can cause 'drug fever', and how do they cause the increase in temperature?

  • Antihistamines
  • Phenothiazines and TCA - impair heat dissipation
  • Cimetidine - blocks receptors in the hypothalamus
  • Anticancer drugs - direct pyrogen.

4

When is fever harmful?

  • Produces disorientation and confusion in elderly or those with underlying brain disease
  • Can cause uncontrolled seizures in young children.

4

What 4 mechanisms do bacteria use to combat environmental fluctuations?

  1. Minimise time between hosts
  2. Non-human reservoirs of infection
  3. Endospore formation
  4. Capsules and S-layers

5

How does hyperthermia differ from fever?

  • Fever is a caused by an increase in set point in the hypothalamus
  • Hyperthermia is a pathological increase in temperature without a change in setpoint of the hypothalamus, with anti-pyretics being ineffective

5

Which bacteria use a non-human animal as a reservoir of infection?

  • Borrelia burgdorferi - tick
  • Yersinia pestis - flea
  • Vibrio cholerae - crustacean moult casts in water towers

6

What opportunistic bacteria gain access to the body when there is trauma to the epithelium?

  • Oral streptococci --> infective endocarditis
  • Pseudomonas spp. --> burns and wounds
  • Pasteurella multocida --> pasteurellosis (cat and dog bite)
  • Streptococcus moniliforms --> rat bite fever
  • Bacteroides spp. --> peritonitis following abdo surgery

7

What are the main endogenous pyrogens?

  • IL-6 --> main
  • IL-1
  • TNF-α

8

What bacteria adheres to the respiratory tract epithelium?

Psuedomonas aeruginosa

9

Where are the 4 areas temperature is measured and which is best clinically?

  1. Oral
  2. Axilla
  3. Tympanic
  4. Rectal -> most reliable

9

What molecules/receptors can bacteria bind to on human cells?

  • Glycoproteins
  • Glycolipids
  • Phospholipids
  • Receptors for cytokines etc
  • Transmembrane proteins
  • Extracellular matrix molecules

10

What are the benefits of fever?

  • Enhanced immune function; T-cell activation and proliferation
  • Inhibition of microbial agents whose ideal temperature is 37oC
  • Interferes with the virulence of both viral and bacterial pathogens.

10

Which bacteria can use curli to bind to cells?

  • E.coli
  • Salmonella spp.

12

What are the clinical presentations of fever?

  • Feeling hot
  • Rigors
  • Excessive sweating
  • Headache
  • Delirium
  • Myalgia and arthralgia
  • Increase RR and HR
  • Dehydration

13

What are the 4 patterns of fever, and what characterises each?

  1. Intermittent fever; the temperature returns to normal at least once every 24 hours
  2. Remittent fever; temperature does not return to normal and only varies a couple of degrees in either direction
  3. Sustained fever; temperature remains high with little variation
  4. Relapsing fever; there is 1 or more episodes of fever lasting as long as several days with 1 or more days of normal temperature

15

What drugs can cause malignant hyperthermia?

  • Halogenated anaesthetics
  • Muscle relaxants such as succinyl choline

Potentially fatal as body temp can reach 43 degrees C

16

Name a bacteria that utilities endospore formation?

Clostrium difficile

17

What 3 mechanisms can bacteria use to penetrate the epithelium?Give an example of bacteria that uses each of the mechanisms.

  • Induce changes in cytoskeleton; actin and microtubules 
    • Yersnia or Salmonella
  • Forcibly enter without cytoskeletal rearrangements
    • Campylobacter jejuni, Klebsiella pneumoniae
  • Penetrate through cell junctions
    • Haemophilus influenzae or Spirochaetes

18

What factors inhibit pathological bacterial colonisation of the skin?

  • Dry conditions
  • Acidic pH (5.5)
  • Regular loss of outer layer - shedding
  • Antimicrobial substances such as FAs and lysozyme
  • SALT
  • Commensal bacteria already living there.

18

What bacterial factors aid the colonisation of the skin and mucous membranes in humans?

  • Adhesins
  • Motility
  • Secretion of mucin degrading enzymes
  • Ability to rapidly react to change in environment
  • Host in poor condition

19

What bacteria are injected into a host through an anthropod, such as a tick or flea?

  • Borrelia burgdorferi --> Lyme disease
  • Yersinia pestis --> plague
  • Francisella tularaemia --> tularaemia
  • Rickettsia typhi --> typhus

20

Which bacteria use their S-layer in cell binding?

  • Aeromonas salmonicidia
  • Lactobacillus acidophilus

21

What factors do the mucous membranes contain that make it difficult for bacteria to colonise?

  • Mucin production and clearance
  • Antimicrobial substances; lysozyme, lactoferrin and anti-microbial peptides
  • Secretory IgA
  • Regular turnover of outer layer
  • MALT
  • Commensals already growing.

22

How do NSAIDs and aspirin reduce fever?

They inhibit the release of PGE2.

23

What bacteria are capable to breaching the epithelium of humans and cause disseminated disease?

  • Salmonella typhi --> typhoid fever
  • Neisseria menengiditis --> meningitis
  • Shigella dysenteriae --> dysentery
  • Treponema pallidum --> syphillis
  • Mycobacterium tuberculosis --> tuberculosis
  • Listeria monocytogenes --> listeriosis

25

Name some exogenous pyrogens.

  • Lipopolysaccharide (LPS)
  • Peptidoglycan
  • Muramyldipeptides

27

What bacteria have a polysaccharide capsule?

  • Haemophilus influenzae
  • Neisseria meningiditis

28

What acute phase proteins are released by the liver in reponse cytokines IL-6, IL-1 and TNF-α?

  • C-reactive protein
  • Complement factor
  • Serum amyloid A
  • Fibrinogen

29

How do the pyrogens alter the setpoint of the hypothalamus?

  • They bind to the receptors in the preoptic area of the anterior hypothalamus and induce the production of PGE2 via the COX-2 enzyme
  • The PGE2 increases the levels of cAMP, altering the responsiveness of the neurones
  • This then increases the thermoregulatory setpoint

30

Where are the 3 sites of post-epithelial invasion?

  1. Circulatory system
  2. Phagocytes
  3. Digest through tissues

31

Where does Bordetella pertussis preferentially adhere to?

The laryngeal epithelia

32

Which bacteria can use fibrils to bind to host cells?

  • Haemophilus influenzae
  • Streptococcus sanguis

33

How much does fever increase the basal metabolic rate?

1oC increase  = 13% increase in BMR

34

Which bacteria use fimbriae in cell binding?

  • E. coli
  • Salmonella typhi serovar Typhimurium
  • Vibrio cholerae
  • Bordetella pertussis
  • Actinomyces spp.

36

Which division of the ANS is inhibited due to an increase in body temperature?

The sympathetic nervous system; leading to vasodilation of cutaneous vessels and stimulation of sweat glands.

36

What bacteria binds to cells using its flagella?

Psuedomonas aeruginosa

38

What is the main antipyretic factor?

IL-10

39

What are the 4 types of flagella arrangement?

  1. Monotrichious - single unipolar
  2. Amphitrichious - single bipolar
  3. Lophotrichious - multiple polar
  4. Peritrichious - multiple all over cell

41

Where does Streptococcus parasanguis adhere to?

Salivary proteins

42

Which bacteria take advantage of behaviours to transmit between hosts?

  • Bordetella pertussis
  • Treponema pallidum

43

Where are the heat sensors located in the brain?

In the preoptic area of the anterior hypothalamus

45

Which bacteria bind to cells using their cell walls?

  • Streptococcus pyogenes
  • Staphylococcus aureus

46

What bacteria can erode through the tooth and cause systemic infection?

  • Streptococcus mutans --> caries (tooth decay)
  • Streptococcus sobrinus --> caries
  • Lactobacillus spp. --> caries
  • Actinomyces spp. --> caries

47

Which bacteria use their capsule in cell binding?

  • Klebsiella pneumoniae
  • Staphylococcus epidermidis
  • Streptococcus pyogenes
  • Bacteriodes fragilis