18 - Chronic Disease + Infections

Question 1

In general, how do chronic conditions lead to a predisposition to infections?

Answer 1

• Disease causes a change in the structure or function of tissues, e.g less mucous
• Consequences of treatment, e.g antibiotics and streroids

Therefore, need successful management to prevent

Question 2

Outline a brief pathophysiology of cystic fibrosis.

Answer 2

Question 3

What are some complications of CF?

Answer 3

Due to thicker secretions of mucous and blocking secretion in pancreas

Question 4

Why do patients with CF get infections?

Answer 4

Their innate immunity is compromised e.g dehydrated, thick mucus so mucociliary escalation cannot occur and there is airway remodelling due to chronic inflammation from infections

Question 5

What are some lung infections that patients with CF are more susceptible to?

Answer 5

Question 6

What is pseudomonas aeruginosa?

Answer 6

• Gram negative bacilli
• Aerobe with flagella

Question 7

Why is pseudomonas aerunginosa difficult to treat and how would you identify it?

Answer 7

Sputum culture to find out what antibiotics sensitive to and what organism

Question 8

How can you prevent patients with CF from developing pseudomonas aerungiosa?

Answer 8

• Try to manage the CF
• Difficult to prevent colonisation

Question 9

How can you treat pseudomonas infections?

Answer 9

• Need combination of antibiotics as develops resistance quickly
• Ciprofloxacin, tazocin, gentamycin, ceftazidime

Question 10

Why do patients with diabetes mellitus become susceptible to infections?

Answer 10

• Hyperglycaemia affects humoral immunity and interferes with neutrophils and lymphocytes
• Micro/macrovascular complications with DM results in poor tissue perfusion so increase risk as no WBC in the area
• Neuropathy causes decrease in sensation so cuts and ulcers go unnoticed, issue with innate immunity as loss of pain

Question 11

What infections are diabetics more susceptible to?

Answer 11

• Cellulitis
• UTI
• Malignant otitis externa
• Respiratory infections

Question 12

Why do patients with DM get cellulitis and what organisms cause this?

Answer 12

Question 13

The patient below has diabetes, what investigations should you carry out once you see this.

Answer 13

Question 14

How can you treat diabetic cellulitis and how can you prevent it?

Answer 14

Treat infection with antibiotics depending on the causative microorganism, e.g flucloxacillin

Question 15

Why do patients with DM get UTIs and what bacteria can cause this?

Answer 15

Question 16

How would you investigate and treat UTIs in a diabetic patient

Answer 16

Question 17

What is a major issue if a patient with type 1 diabetes acquires an infection?

Answer 17

At risk of DKA

Question 18

What is malignant otitis externa and what causes it?

Answer 18

• External ear infection that starts in external auditory canal
• Can spread to soft tissue, cartilage and bone
• Severe ear pain, otorrhoea

- Pseudomonas aerungiosa

Question 19

Why are diabetic patients susceptible to respiratory infections and what are the organisms typicaly causing this?

Answer 19

- Hyperglycaemia interfering with neutrophil function

- Altered perfusion due to vascular disease cause inflammatory damage

- Can give influenza vaccines to these patients

Question 20

Why do patients with COPD get infections?

Answer 20

• Increased mucus production
• Local overreactivity causing inflammation and damage to airways
• Airway remodelling due to damage to the cilia

Question 21

What infections are patients with COPD susceptible to?

Answer 21

• Pneumonia

- Common organisms: atypical community acquired, e.g H.Influenzae, Ps.aeruginosa

- Rare organisms: S.pneumoniae, moraxella cararrhalis, E.coli

Question 22

Where is pseudomonas aeruginosa normally found?

Answer 22

Soil, water, plants and animals and normally doesn’t cause disease when in human, apart from if human is immunocompromised

Question 23

What diseases can P.aerungiosa cause?

Answer 23

Nosocomial UTI, pneumonia, surgical site infections, severe burn infections, chemotherapy patients infection

Question 24

What is the pathogenesis of P.aeruginosa?

Answer 24

• Mucoid capsule containing alginate that allows resistance to phagocytosis and clearing in CF lung
• Host tissue damage allows bacteria to adhere so it releases numerous toxins that promote local invasion

Question 25

What localised infections can P.aeruginosa cause?

Answer 25

• Keratitis in eye
• Ear, e.g swimmers ear and external otitis
• Skin rashes in contaminated hot tubs
• Diarrheoa
• Abscesses

Question 26

What is the FEVER pain score?

Answer 26

Helps you to decide whether or not to prescribe antibiotics in a case of pharyngitis