L20 - Chronic diseases and infections

Question 1

How do chronic diseases predispose patients to particular infections?

Answer 1

Can alter the structure and fuction of tissue and organs/alter the microbial presence due to treatment

Question 2

What mode of inheritance does Cystic Fibrosis show?

Answer 2

Autosomal recessive

Question 3

Explain the pathophysiology of CF

Answer 3

Defect in the CFTR chloride channel -> reduced secretion of osmotically active chloride -> water doesn’t follow -> thick mucus -> builds up in lungs

Question 4

Name some specific complications related to CF

Answer 4

Lung infection due to microbes in the mucus/ pancreatitis/bowel obstruction/liver cirrhosis/sinus infections/infertility

Question 5

Name three bacteria that CF patients are particularly at risk of causing lung infections

Answer 5

MAIN ONE - Pseudomonas aeruginosa/S.aureus/H.influenzae/fungi like Candida albicans and Aspergillus

All causing lung infections

Question 6

Pseudomonas aeruginosa is an aerobic bacteria, describe it’s structure

Answer 6

gram negative bacilli/ Causes opportunistic infections/ biofilm agent

Question 7

What sample would you take in someone with CF to identify P aeruginosa infections?

Answer 7

sputum/urine depending on type of indections caused

Question 8

Name two preventative meaasure CF patients can take to prevent respiratory infections

Answer 8

Chest physio/Nebulisers/bronchodilators/god nutirtion/good hand hygiene

Question 9

What is the treatment for pseudomonas infection and why?

Answer 9

These rapidly develop resistance so require a combination of antibiotics - normally Tazocin and gentamycin/cirpofloxacin/ceftazidime

Question 10

Why are diabetic patients at a higher risk of infection? Give two reasons

Answer 10

Hyperglycaemia impairs neutrophil and lymphocyte function/vascular disease caused by it leads to poor tissue perfusion and increased infection risk/neuropathy causes increased risk of cuts going unnoticed

Question 11

Name two infections that diabetic patients are particularly at risk of

Answer 11

cellulitis/UTI/s/malignant otis externa/respiratory infections

Question 12

What are the major causative organisms for cellulitis?

Answer 12

S. aureus/ Group A strep (S. pyogenes)/ polymicrobial often

Question 13

A man walks into A and E with a severe foot ulcer, he is diabetic. What do you do?

Answer 13

Clean the wound
Swab the site
blood cultures
check HbA1c
FBC, CRP
U and E’s (kidney function important in diabetes)
Foot X-ray to see if infection has reached bone

Question 14

Why are UTI’s common in diabetic patients?

Answer 14

Neuropathy leads to defects in bladder emptying -> stasis -> increased risk of infections

Question 15

What are the causative organisms for UTI’s?

Answer 15

E. coli/P. aeruginosa

Question 16

What investigations would you carry out in a patient presenting with a UTI?

Answer 16

Nitrites and leucocytes
Glycosuria
potentially a sepsis screen
FBC/CRP/ U and E’s

Question 17

Malignant otis externa is a complication of diabetes mellitus. It is an infection which has spread to the soft tissue, bone and cartilage. Patients typically present with severe ear pain and otorrhea (ear discharge). What is the causative organism?

Answer 17

P. aeruginosa

Question 18

Explain COPD

Answer 18

Chronic inflammatory response as a result to long term irritation by smoking -> airway remodelling and increased mucus production

Question 19

Pneumonia is a common complication associated with COPD. What are the main causative organisms?

Answer 19

H. influenzae/P. aeruginosa