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Path: inflamm diseases of bowel (ii) (Diverticular disease (complications,…
Path: inflamm diseases of bowel (ii)
Vasc disorders
ischaemic bowel disease
may affect SI, LI or both
may be acute or chronic
severity of injury depends on vessels involved
transmural infarct
all layers of wall affected (incl serosa)
due to sudden occlusion (thrombosis/embolism) of a major vessel
commoner in older people
severe abdo pain
bloody diarrhoea
decreased peristaltic sounds
rigidity
may perforate - peritonitis + sepsis
90% mortality rate
mucosal + mural infarcts
mural: necrosis of mucosa + submucosa
mucosal: necrosis of mucosa only
non-specific abdo complaints
intermittent bloody diarrhoea
may heal if lesion corrected
often due to hypoperfusion (esp in watershed areas + patients with HF)
chronic ischaemic bowel disease
inflamm (chronic iscahemic colitis)
ulceration
mucosal atrophy
fibrosis a/w strictures in some cases
intermittent bloody diarrhoea
often confused with IBD
always consider in patients with unexplained abdo pain +/or GI bleeding
multiple mechanisms
art occlusion
thrombosis (atherosclerosis, vasculitis)
embolism
clots
chol
cardiac vegetations from infective endocarditis
venous thrombosis
hypercoaguable states (e.g. polycythaemia ruby vera)
drugs
non-occlusive
HF
shock
drugs
other
radiation
volvulus
strangulation
angiodysplasia
tortuous dilations of blood vessels
usually in caecum + right colon
acquired malformed vessels in mucosa + submucosa
usually in elderly
wear + tear
result of yrs of mechanical trauma
may account for both chronic + acute lower GI blood loss if they rupture + bleed into intestinal lumen
Hereditary haemorrhagic telangiectasia
AD
thin walled blood vessels in mouth + GIT
may rupture - bleeding
haemorrhoids
variceal dilatation of submucosal venous plexi around anus + rectum
common
predisposing factors
constipation (increased pressure in veins)
venous stasis of pregnancy (womb compresses pelvic veins)
portal HTN
can be int (inside anus) or ext (under skin around anus - painful swelling due to thrombosis)
bright red stool
Diverticular disease
diverticulum = blind pouch leading off alimentary tract communicating with the lumen
the the colon there are defects/anatomic weaknesses in the muscle wall where Ns + blood vessels penetrate (where vasa recta traverse muscularis propria)
prevalence = 50% in over 60s in Western countries
low fibre diet -> decreased stool bulk -> reduced peristaltic contractions -> increased intraluminal pressure -> herniation of wall through anatomic weak points
true diverticula involve all layers of bowel
pseudo diverticula involve only mucosa + submucosa
almost always in sigmoid colon
usually asymp
20% of cases a/w cramping/lower abdo pain
constipation
tenesmus (sensation of never being able to empty rectum completely
tx
high fibre diet (may prevent progression)
surgical intervention for obstructive/inflamm complications
complications
diverticulitis
may be caused by obstruction of the narrow neck, impaction of faecal material, constriction of blood supply or infection
perforation
adhesions
fistula formation (e.g. bladder)
pericolic abscess formation
inflamm mass formation
haemorrhage - rectal bleeding
obstruction
Hernia
weakness in wall of peritoneal cavity, permitting protrusion of serosa-lined sac of peritoneum
inguinal + femoral canals, umbilicus, scars (post-op - incisional hernia)
organs may get trapped in hernial sac (bowel or omentum) - may lead to incarceration + strangulation
adhesions
due to previous surgery, peritonitis, endometriosis
fibrous bands may develop between loops of bowel, or between organs + abdo wall
can create closed loops = strictures
intussusception
telescoping of proximal segment of bowel into distal segment
in elderly almost always a tumour @ the leading edge
in children, most common cause is lymphoid hyperplasia (terminal ileum to caecum)
volvulus
twisting of a loop of bowel along its mesentery, cutting off the blood supply + resulting in acute ischaemia
common locations: sigmoid colon (elderly), caecum (young adults)