Infection Session 9

Question 1

How can chronic diseases be acquired?

Answer 1

VITMAMIN DEI
Vascular
Infective
Trauma
Autoimmune
Metabolic
Inflammatory
Neurological/neoplasia
Degenerative
Environmental
Idiopathic

Question 2

What is the most common gene mutation inherited by cyctic fibrosis patients?

Answer 2

Delta F508 (deletion of phenylalanine at position 508)

Question 3

Why do CF patients require close nutritional monitoring?

Answer 3

Good nutrition must be maintained otherwise malnutrition due to impaired pancreatic function predisposes to infection

Question 4

What is bronchiectasis?

Answer 4

Widening of bronchi and bronchioles

Question 5

What causes bronchiectasis in CF?

Answer 5

Dehydrated, thick mucus which blocks small ducts

Question 6

What is the procession of different organisms that cause pneumonia in CF pts?

Answer 6

H.influenzae (v.early in children)–> staph aureus –> pseudomonas aeruginosa/burkholderia cepacia –> atypical mycobacteria, candida albicans, aspergillus fumigatus

Question 7

What two types of congenital chronic disease are there?

Answer 7

Genetic

Developmental

Question 8

Why is lung exercise in CF pts important in reference to infection?

Answer 8

Reduces risk of Pseudomonas aeruginosa and Burkholderia cepacia colonisation

Question 9

Why is contact between Cf pts kept to a minimum?

Answer 9

Pseudomonas aeruginosa and Burkholderia cepacia can be transmitted person to person

Question 10

What does the higher frequency of CF gene carriage in the UK population in comparison to other populations suggest?

Answer 10

Balanced polymorphism

Question 11

What is balanced polymorphism?

Answer 11

2 different versions of one gene are maintained in the population as this confers better survival than 2 copies of either gene alone

Question 12

What in-vitro interactions w/ CFTR proteins suggest carrying a CF gene confers resistance to cholera, typhoid or TB?

Answer 12

Cholera toxin

Salmonella typhi intracellular entry

Question 13

What is the pathogenesis of COPD?

Answer 13

Acquired/genetic cause –> inhalation of steroids –> neutrophils and macrophages cause chronic inflammatory response –> free radical production and damage to cilia –> breakdown of lung tissue, small airways disease and increased mucus production

Question 14

How do acute exacerbations of COPD present?

Answer 14

Sudden episode of excess coughing

Colour change in sputum of white-grey to yellow-green

Question 15

What are common bacterial causes of COPD exacerbation?

Answer 15

H.influenzae

Ps.aeruginosa

Question 16

What are common viral causes of COPD exacerbation?

Answer 16

RSV
Rhinovirus
Parainfluenza

Question 17

Why is evidence of a viral infection more definitive than bacterial?

Answer 17

No risk of sample contamination by RT commensals

Question 18

What effects do hyperglycaemia and acidaemia in diabetes have on humoral and cellular immunity?

Answer 18

Impair humoral –> decrease ability to produce antibodies

Impair polymorphonuclear leukocyte and lymphocyte functions

Question 19

What is the pathogensis of vascular implications leading to infection in diabetes?

Answer 19

Diabetic micro- and microvascular disease –> poor tissue perfusion –> increased risk of peripheral BV disease and increased risk of infection

Question 20

How does diabetic neuropathy lead to infections in diabetic pts?

Answer 20

Decreased skin sensation allowing unnoticed skin breaks to form ulcers and can lead to osteomyelitis
Neurogenic bladder causes incomplete bladder emptying

Question 21

Which ENT infection is only seen I diabetic pts?

Answer 21

Pseudomonas aeruginosa infection causing malignant/necrotising otitis externa

Question 22

What is the pathogenesis of malignant/necrotising otitis externa?

Answer 22

Pseudomonas aeruginosa in external auditory canal spreads to adjacent tissues –> ear pain and otorrhoea

Question 23

What colonises the nose and paranasal sinuses of poorly controlled diabetics?

Answer 23

Mould fungi

Question 24

What is rhinocerebral mucormycosis, seen in DKA pts?

Answer 24

Nasal fungi spread to adjacent tissues by invading BV –> soft tissue necrosis and bony erosion

Question 25

What leads to diabetic foot ulcers and necrotising fasciitis in diabetic pts?

Answer 25

Sensory neuropathy+atherosclerotic vascular disease+hyperglycaemia

Question 26

Give some examples of CNS diseases that affect bladder control.

Answer 26

``` Alzheimer's Birth defects of spinal cord Cerebral palsy Encephalitis Learning disabilities MS Parkinson's Spinal cord injury Stroke ```

Question 27

Give some examples of PNS diseases that can affect bladder control.

Answer 27

``` Neuropathy Long term heavy alcohol use Long term diabetes Vit B12 deficiency Syphilis Pelvic surgery Herniated disc/spinal cord stenosis ```

Question 28

Is there a link between Down's syndrome and infection risk?

Answer 28

Yes, seems to be elevated as bacterial and viral RTIs seem to be more common in young people w/Down's syndrome but no well proven and no explanation

Question 29

What laboratory observations of humoral immunity are seen in a Down's syndrome pt?

Answer 29

Decreased neutrophil and monocyte function but normal number Decreased IgG in infants and raised in adults Decreased specific antibody response on immunisation (still respond clinically if otherwise healthy)

Question 30

What laboratory observations have been made in pts with Down's syndrome of their cellular immunity?

Answer 30

Altered T cell distribution but normal T cell Decreased T cell function Altered T cell intracellular signalling Abnormal cytokine production Decrease of some NK functions but increase in number of NK cells