Week 9 - Chronic Diseases And Infections Flashcards
Why do chronic diseases often make you more prone to infection?
They cause a change in the structure or function of affected tissues and organs which may have the potential for changing the way they interact with microorganisms, this may be affected further by the consequences of treatment
What is the pathogenesis of cystic fibrosis?
Autosomal recessive, defect in cystic fibrosis transmembrane conductance regulator gene in exocrine glands
What are the clinical consequences of cystic fibrosis?
Defect in CFTR leads to defects in Cl- transmembrane transport
Mucous becomes dehydrated and thick causing blockage in small ducts
This can lead to lung colonisation
What are the common organisms that colonise the lungs in a person with cystic fibrosis?
H influenzae, staph aureus, pseudomonas aeruginosa, burkholderia ceoacia, atypical mycobacteria, candida albicans, aspergillus fumigatis
What does pseudomonas aeruginosa look like on agar?
Shiny as it is a mucoid so produces mucous
What is chrinic obstructive pulmonary disease?
Chronic inflammatory response to inhaled irritants
primarily mediated by neutrophils and macrophages
Causes breakdown of lung tissue, narrowing of airways and increased mucous production
Name some bacteria that are likely to affect someone with COPD?
Snpnneumoniae, H influenzae, E coli, Ps aeruginosa
Name some viruses that are likely to affect someone with COPD?
Adenovirus, coronavirus, parainfluenza virus, rhinovirus
How does diabetes increase the risk of infection?
Causes hyperglycaemia and academia impairment
Diabetic microvascular and macrovascular disease results in poor tissue perfusion and increased risk of infection
Diabetic neuropathy causes diminished sensation resulting in unnoticed skin lesions
What is malignant or necrotising otisis externa?
Caused by pseudomonas aeruginosa
infection starts in the external auditory canal and spreads to adjacent soft tissue, cartilage and bone
Patients typically present with severe ear pain and otorrhoea
Occurs in diabetics
What is rhinocerebral mucormycosis?
Especially happens in those with diabetic ketoacidosis
Mould fungi
Organisms colonise the nose and paranasal sinuses spreading to adjacent tissues by invading blood vessels and causing soft tissue necrosis and bony erosion
Why are diabetes more likely to get urinary tract infections?
Neurogenic bladder due to diabetic neuropathy leads to defects in bladder emptying
caused by Ps aeruginosa or enterobacterieae e.g. e coli
What organisms cause skin and sort tissue infections in diabetes?
Staph aureus - folliculitis and cellulitis
Group A beta-haemolytic streptococcus - cellulitis
Enertobacterieae and various anaerobes can cause diabetic foot ulcers and necrotising fasciitis
What infections are you predisposed to if you have down syndrome?
Respiratory tract in young people - may be due to immunodeficiency or things like altered mucous secretion
How is humoral immunity affected in downs syndrome?
Decreased neutrophil and monocyte function but normal number of these
Immunoglobulin levels lowered in infants and raised in adults
Might have raised IgA in older children and adults
Lowered specific antibody responses upon immunisation
May have raised C3,4 and
