Week 9 - Chronic disease and infections

Question 1

What bacterial infections are associated with COPD?

Answer 1

• Haemophilus influenzae

- Pseudomonas aeruginosa

Question 2

What viral infections are associated with COPD?

Answer 2

• Resp syncytial virus

- Rhinovirus

Question 3

Why are people with diabetes mellitus more prone to infection?

Answer 3

• Hyperglycaemia and acidaemia impair humoral immunity and lymphocyte/neutropil function
• Poor tissue perfusion increases risk of infection
• Diabetic neuropathy decreases sensation resulting in greater damage to physical barriers

Question 4

What ENT infections are associated with diabetes mellitus?

Answer 4

• Necrotising Otitis externa

- Rhinocerebral mucomyocosis

Question 5

What is necrotising otitis externa?

Answer 5

-Infection of the external auditory canal which spreads toadjacent bone and soft tissue caused by Pseudomonas aeruginosa

Question 6

What causes rhinocerebral mucomyocosis?

Answer 6

-Mould colonising nose and paranasal sinuses causes soft tissue necrosis and bony erosion

Question 7

Why are UTIs associated with diabetes mellitus?

Answer 7

-Neuropathy can lead to neurogenic bladder causing decreased emptying and increasing susceptibility to infection

Question 8

What is cystic fibrosis?

Answer 8

• Autosomal recessive disease characterised by a defective/absent cystic fibrosis transmembrane conductance regulator gene producing defective/absent chloride channels in exocrine glands
• This produces viscous dehydrated mucus which is hard to clear and causes blockages in small ducts

Question 9

Why do cystic fibrosis have unusual lung colonisation?

Answer 9

-Lung damage, recurring Abx and steroid treatment open a niche for unusual colonisation

Question 10

Why is pseudomonas aeruginosa of particular significance in CF patients?

Answer 10

• Mucoid strain in CF patients produce a biofilm to aid colonisation
• Already have a defective muco-ciliary esculator so cannot be cleared and biofilm aids evasion of immune system

Question 11

Describe a pneumonic for remembering categories of disease

Answer 11

• Vascular
• Infective
• Traumatic
• Autoimmune
• Metabolic
• Inflammatory
• Neoplastic
• Degenerative
• Idiopathic
• Congenital
• Environmental

Question 12

Why do infections occur in chronic disease?

Answer 12

• Chronic disease changes structure and function of tissue/organ which predisposes to disease
• Altered presence of micro-organism can alter host interactions
• Consequences of treatment of chronic disease eg antibiotics, steroids