infection - chronic diseases & infection Flashcards
what do chronic diseases cause?
a change in the structure or function of affected tissues / organs which may have the potential for changing the interaction between the patient and micro-organisms
e.g. H.pylori colonising duodenal cap (metaplasia)
what can chronic diseases subsequently and further affect?
altered presence of micro-organisms and the consequences of treatment e.g. antibiotics & steroids
what are the congenital causes of chronic diseases?
genetic
developmental - embryology (Down’s syndrome, Robersonian translocation, not inherited)
what are the acquired causes of chronic diseases?
VITAMIN NDIE vascular - vasculitis inflammatory - IBD trauma autoimmune - SLE metabolic - Cushing's, DM infective - TB, chicken pox neurological - neurological bladder neoplastic degenerative - MS, Parkinson's idiopathic environmental
pathogenesis of cystic fibrosis
autosomal recessive
defect in CFTR gene in exocrine glands
range of different mutations
most frequent: deletion of phenyalanine
what are clinical consequences of CF?
defect in Cl- transmembrane transport
mucus becomes dehydrated - block small ducts
lung colonisation & infection with different organisms
lung damage, antibacterial & steroid treatment
what are the different infections in CF?
- H. influenzae
- staph aureus (meticillin, trimethoprim)
- Pseudomonas aeruginosa (UTI), Burkholderia cepacia
- atypical mycobacteria, candida albicans, aspergillus fumigatus
(mucoid pseudomonas aeruginosa in CF - produces lots of extracellular polysaccharide - shiny)
what is COPD?
- chronic inflammatory response to inhaled irritants, primarily mediated by neutrophils (emphysema) & macrophages (chronic bronchitis)
- breakdown of lung tissue (emphysema) & small airways disease (obstructive bronchiolitis) - thickening mucosa, remodelling, widening large airways (bronchiectasis)
- increased mucus production
what are bacterial acute exacerbations of COPD?
S. pneumoniae H. inflenzae Moraxella catarrhalis Ps aeruginosa E. coli
what are viral acute exacerbations of COPD?
respiratory syncytial virus (RSV) adenovirus coronavirus parainflenza virus rhinovirus (common cold) influenza A virus human metapneumovirus
how does diabetes lead to increased infection?
- hyperglycaemia & acidemia impairs: humoral immunity, polymorphonuclear leukocyte & lymphocyte functions
- diabetic microvascular & macrovascular (stroke, MI) disease results in poor tissue perfusion –> increased risk of infection
- diabetic neuropathy causes diminished sensation - unnoticed skin e.g. foot ulcers
diabetes leading to ENT infections?
malignant / necrotising OTITIS EXTERNA: pseudomonas aeruginosa (skin infection) starts in external auditory canal, spreads to adjacent soft tissue, cartilage, bone present: severe ear pain & otorrhoea (discharge from ear)
diabetes and UTI
neurogenic bladder (diabetic neuropathy) - defects in bladder emptying increased risk of asymptomatic bacteriuria & pyuria, cystitis & upper UTI causes: enterobacteriaceae (e.g. E. coli), Pseudomonas aeruginosa, (Staph a & epidermadis)
what are neurological (CNS diseases) affecting bladder control?
motor neurone affected: Alzheimer's disease MS Parkinson's spinal cord injury stroke ADHD
what are neurological (PNS diseases) affecting bladder control?
neuropathy (nerve damage) - can be diabetic / long-term alcohol use
vitamine B12 deficiency (pernicious anaemia)
nerve damage from pelvic surgery, herniated disc, syphilis (STD)
