Acute inflammatory diseases Flashcards
Describe appendix anatomy
extension of LI mesoappendix connects to ileum microscopically similar to colon young people have lining interspersed with lymphoid follicles mucosa, submucosa, muscularis, serosa
what are the causes of luminal obstruction in the appendix
foceal, gallstone, tumour, worms
describe the pathogenesis of appendicitis starting from luminal obstruction
-> mucus increases pressure -> mucosal ischaemia -> mucosal injury -> acute mucosal inflammation -> 2ndry bacterial invasion -> spread inflammation transmurally
what are the 3 stages of appendicitis
early acute,
acute suppurative
acute gangrenous
what happens in early acute appendicitis
neutrophilic exudate in mucosa
mild inflammation
what happens in acute suppurative appendicitis
transmural inflammation (tense, thick wall)
mucosal ulceration + purulent exudate in lumen (viscous cloudy fluid)
inflamed serosa and with fibrinopurulent exudate, microabscesss (pathcy, pale)
hyperaemia
what happens in acute gangrenous appendicitis
necrosis extends to muscularis externa because neutrophils -> enzymes + free radicals
rupture + acute peritonitis
clinical features of appendicitis
pain, low fever, nausea, vomiting, anorexia, neutrophilia
difficult to diagnose in old/young
many differentials
how does pain progress in appendicitis
starts as vague cramps progresses to be localised
complications with perforation in appendicitis
spread faeces into peritoneal cavity
local peri-appendical abscess or general peritonitis
complications with general peritonitis in appendicitis
ileus (temporary lack of the normal muscle contractions of the intestines)
cause temporary arrest of peristalsis and abdominal distention
incrrease fever, tenderness + rigidity
complications of septic shock in appendicitis
gram negative bacteria from GIT enter bloodstream
bacterial death releases lipopolysaccharides which cause endothelial injusry and cytokine release which causes widespread vasodilation
systemic septic shock -> myocardial injuriy + lowering BP
meninges anatomy
dura + arachnoid + pia mater
subarachnoid space circulates CSF therefore infection sprad rapidly
ROUTE OF cns INFECTION
haematogenous, direct traumatic implementation, local extension of infection or from pNS
damage from CNS infection caused by …
direct infectious injury, roxins, inflammatory response, immune mediates mechanisms
causes of APM
microorganisms neonates = e.coli + b streptococci infants = strep pneumoniae adolescents = neisseria meningitidis elderly strep pneum. + lysteria monocytogenes
symptoms apm
systemic infection, headache, photophobia, irritability, cloudy consciousness, bulging fontanelle, neck stiffness
how is apm diagnosed
spinal tap = gluid has high nuetrophil count, high proteins and low glucose
what are the complications of apm
cerebral oedema and increased ICP
infection spread to brain parenchyma causing focal cerebritis
exudate can ogranise causing adhesions to teh meninges and the CSK blockes = hydrocephalus
compress cranial nerve causing palsies
affect blood vessels causing thrombosis and infarctions
sepsis
what is meningococcaemia
blood infection from meningitis
bacterial replicates releases endotoxins which interact with macrophages to release cytokines and free radicals
damage vascular endothelium and platelet deposition causes vasculitis and petechial haemorrhage
multiorgan shock
describe the macroscopy of meningitis
brain swollen + leptomeninges are congested
purulent exudate over cerebral hemispheres + brain base
oedematous white matter
ventricular enlargement