Session 9 - Chronic Health And Infections

Question 1

How can chronic diseases have an impact on infections in general?

Answer 1

• Changing structure + function of tissues/organs may have an impact on how they interact with micro-organisms
• Treatments for the chronic infections may further effect this interaction (e.g. Antibiotics +steroids)

Question 2

Describe the pathogenesis of Cystic Fibrosis

Answer 2

• autosomal recessive inheritance pattern
• causes a defect in CFTR channel, meaning chloride transport is hampered
• water cannot be added to mucus secretions, so they are very thick
• blocks small ducts, can’t be cleared

Question 3

How does Cystic Fibrosis make sufferers more susceptible to infections?

Answer 3

• Thick, dehydrated mucus cannot be cleared
• stasis of the mucus provides a surface to which pathogens can adhere and cause infection
• also if ducts are blocked there will be stasis of secretions proximal to the blockage hence more at risk of infections this way

Question 4

Describe Pseudomonas Aeruginosa

Answer 4

• Aerobic, G -ve opportunistic bacteria
• most common infectious cause in CF patients
• spread by direct or indirect contact
• forms biofilms on the mucosal surface

Question 5

If a CF patient presented with a Pseudomonas Aeruginosa infection, what would be the symptoms at first?
And what would the more chronic symptoms be?

Answer 5

Early symptoms: Coughing + Haemoptysis

Progresses to: Pulmonary Hypertension, Hypoxia + Bronchiectasis

Question 6

Why are diabetic patients more susceptible to infections?

Answer 6

• Hyperglycaemia + acidaemia impair humoral immunity + lymphocyte and leukocyte function
• Poor tissue perfusion predisposes to higher risk of infection
• Unnoticed skin infections due to peripheral neuropathy

Question 7

What is the organism responsible for the Necrotising Otitis Externa infection?

Answer 7

Pseudomonas Aeruginosa

Question 8

How does a Necrotising Otitis externa infection start, how does it spread through he body, and how would it present?

Answer 8

• Starts in the external auditory canal
• Spreads through adjacent soft tissue, cartilage and bone
• Presents with severe ear pain + otorrhoea (ear discharge)

Question 9

Which diabetic patients are particularly at risk of Rhinocerebral mucorymyocis?

Answer 9

Those with poorly managed diabetes + those with DKA

Question 10

Was does Rhinocerebral mucorymyocis first colonise, how does it spread in the body and what does damage does it cause?

Answer 10

• First colonises thee nose and paranasal sinuses
• Spreads through blood vessels
• Causes soft tissue necrosis and bone erosion

Question 11

Why are diabetics more at risk of UTIs?

Answer 11

• Neurogenic bladder due to neuropathy
• Bladder doesn’t empty fully
• Leads to stasis of urine in the bladder which makes the urine more easy to colonise by bacteria and cause infection

Question 12

What factors of poorly controlled diabetes make these patients predisposed to skin and soft tissue infections?

Answer 12

• Sensory neuropathy
• Atherosclerotic vascular disease
• Hyperglycaemia

Question 13

Which bacteria are likely to cause soft tissue and skin infections in diabetic patients?

Answer 13

• Staph aureus
• Group A/B haemolytic streptococci
• Enterobacteria
• Various Anaerobes

Question 14

What infections are patients with Down’s Syndrome more likely to get?

Answer 14

Respiratory Tract Infections

Question 15

Why may Down’s syndrome patients be more susceptible to infections?

Answer 15

• Decreased neutrophil and monocytes functionality
• Decreased immunoglobulin levels
• Decreased specific antibody responses upon immunisation
• Decreased T cell functionality