GASTRO 2 Flashcards
what can intestinal ischaemia be classified into ?
acute mesenteric ischaemia (embolic mesenteric ischaemia, thrombotic mesenteric ischaemia and venous mesenteric ischaemia)
chronic mesenteric ischaemia
colonic ischaemia (ischaemia colitis, the most common type and has the best prognosis)
what are the causes for ischaemia bowel disease?
Arterial compromise
embolism - 50% of acute mesenteric events - usually originates from a left sided heart thrombus or from spontaneous or iatrogenic rupture and embolism from an aortic atherosclerotic plaque or aneurysm (interventional radiological procedures are the most common cause of iatrogenic plaque rupture.
thrombosis - acute ischaemia results from thrombus occurring as a progression of atherosclerosis at the origin of the superior mesenteric artery. subacute or chronic ischaemia may result from partial occlusion of the vessel.
vasculitis - different causes of vasculitis can lead to mesenteric ischaemia
Venous compromise
venous thrombosis - frequently involves the superior mesenteric vein. Usually associated with cirrhosis or portal HT.
Hypoperfusion - shock, hypotension or relative mesenteric hypotension. Heart failure, dialysis, drug related, recent surgery or trauma, infection.
what is the blood supply to the foregut?
the foregut is the stomach and part of the duodenum, biliary system, liver, pancreas
it is supplied by celiac artery
what is the blood supply to the midgut?
the mid gut is the duodenum to the 1st half of the transverse colon
it is supplied by the superior mesenteric artery
what is the blood supply to the hindgut?
the hindgut is the snd half of the transverse colon to the rectum
it is supplied by the inferior mesenteric artery
how does acute mesenteric ischaemia present?
acute severe abdominal pain , sudden onset and out-of-keeping with physical exam findings
later can develop shock, peritonitis and systemic inflammatory response
how does chronic mesenteric ischaemia present?
relatively rare clinical diagnosis due to its non-specific feature and may be thought of as intestinal angina. Colicky, intermittent abdominal pain occurs.
abdominal bruit may be heard
there may be rectal bleeding, malabsorption and nausea and vomiting
how do you manage acute mesenteric ischaemia?
urgent surgery is usually required - poor prognosis especially if surgery is delayed as life threatening complications such as septic peritonitis and progression of a systemic inflammatory response syndrome into a multi organ dysfunction syndrome mediated by bacterial translocation across the dying gut wall - if this happens resus with fluids and antibiotics is needed and usually a heparin is required
if non-occlusive - papaverine infusion and observation
if embolus - endovascular therapy, +/- open embolectomy or arterial bypass +/- bowel resection
if thrombosis - heparin plus endovascular therapy +/- arterial reconstruction or bypass +/-bowel resection plus papaverine infusion
if mesenteric vein thrombosis - anticoagulation plus observation
if vasculitis - corticosteroid - IV methylprednisolone
how do you manage chronic mesenteric ischaemia?
surgical systemic-mesenteric bypass
if not surgical candidate - medical optimisation and percutaneous angioplasty and stenting
which areas are most susceptible to ischaemia colitis?
watershed areas - splenic flexure and caecum
which are borders of the territory supplied by the superior and inferior mesenteric arteries.
who is at risk of ischaemic colitis?
the elderly
people with underlying atherosclerosis and vessel occlusion
also occurs in younger people - associated with contraceptives, thrombophillia and vasculitis
what is ischaemic colitis ?
it describes acute but transient compromise to the blood flow in the large bowel - it may lead to inflammation, ulceration and haemorrhage.
what will x-ray show in someone with ischaemic colitis?
thumb printing due to mucosal oedema/haemorrhage
how do you manage ischaemic colitis?
usually supportive
surgery may be required in a minority of cases if conservative measures fail - indications would include generalised peritonitis, perforation or ongoing haemorrhage
they may need segmental colectomy
how would ischaemic colitis present?
abdominal pain and rectal bleeding
what investigations would you preform for bowel ischaemia?
FBC (look for leukocytosis, anaemia, evidence of haemoconcentration)
chemistry panel including serum lactate
coagulation studies
ABG
ECG - look for AF, arrhythmia, acute MI which may have caused the intestinal ischaemia)
erect CXR - look for free air = perforation present
abdominal X-ray - air fluid levels, bowel dilation, bowel wall thickening, pneumatosis)
CT scan with conrast/CT angiogram
sigmoidoscopy or colonoscopy
what are the risk factors for ischaemic bowel disease?
old age smoking history hyper coagulable states AF MI structural heart defects vasculitis
what are haemorrhoids?
abnormal swelling or enlargement of the anal vascular cushions - the anal vascular cushions act to assist the anal sphincter in maintaining continence. When these cushions become abnormally enlarged they can cause symptoms and become pathological haemorrhoids.
where are the hemorrhoidal cushions usually positioned?
left lateral, right posterior and right anterior portions (3 o’clock, 7 o’clock, 11 o’clock)
how are haemorrhoids classified?
usually classified according to their size
1st degree - remain in the rectum
2nd degree - prolapse through the anus on defecation but spontaneously reduce
3rd degree - prolapse through anus on defecation but require digital reduction
4th degree - remain persistently prolapsed
there are two types:
external - originate below the dentate line, prone to thrombosis and may be painful
internal - originate above the detonate line and do not generally cause pain.
what are the risk factors for haemorrhoids?
excessive straining (from chronic constipation) increasing age raised intra-abdominal pressure (such as pregnancy, chronic cough or ascites)
what are the clinical features of haemorrhoids?
painless bright red rectal bleeding, commonly after defecation and often seen either on paper or covering the pan - importantly blood is seen on the surface of the stool not mixed in.
there may be pruritus, rectal fullness or an anal lump and soiling.
large prolapsed haemorrhoids can thrombose - these can be very painful and patients frequently present as an emergency
examination may be normal unless haemorrhoids have prolapsed
what differentials would you want to exclude with rectal bleeding?
malignancy
IBD
diverticular disease
other differentials to consider - fissure-in-ano, perianal abscess or fistula-in-ano.
what investigations should be performed for haemorrhoids?
Proctoscopy is typically performed to confirm the diagnosis
may consider FBC if prolonged or significant bleeding
sigmoidoscopy or colonoscopy may be considered to exclude malignancy
how are haemorrhoids managed?
dietary and lifestyle - increase fibre and adequate fluids
for symptoms - anusol cream, local anaesthetic e.g. instillagel, topical steroids
may also consider laxatives
grade one - topical corticosteroids - hydrocortisone rectal
grade 2 - rubber band ligation or haemorrhoidal artery ligation
surgical options remain for grade 3 and 4 - haemorrhoidectomy (stapled haemorrhoidectomy or milligan morgan haemorrhoidectomy )
what is a pilonidal sinus?
pilonidal sinus disease is a disease of the inner-gluteal region characterised by the formation of a sinus in the cleft of the buttock - most commonly affecting males aged 16-30
these do not communicate with the anal canal (this occurs in a perianal fistula)
what causes a pilonidal sinus to occur?
hair follicles become inserted into the skin, creating a chronic sinus tract - this promotes a chronic inflammatory reaction, causing epithelialised sinus
what are the risk factors for a pilonidal sinus?
caucasian males with coarse dark body hair
classically associated with those who sit for prolonged periods
increased sweating buttock friction obesity poor hygiene local trauma
*typically does not occur after the age of 45
what are the clinical features of pilonidal sinus?
intermittent red, painful and swollen mass in the sacrococcygeal region.
commonly discharge form the sinus
there may be systemic signs of infection
what investigations would you perform for pilonidal disease?
usually a clinical diagnosis
a rigid sigmoidoscopy or MRI may be needed to distinguish between sinus and perianal fistula.
how do you manage pilonidal disease?
doesn’t always require surgical treatment - conservative management involves shaving the effected region and plucking the sinus free of any hair that is embedded. any accessible sinuses can be washed out with water to prevent infection
pain relief
abscess will require surgical drainage
septic episodes can be treated with antibiotics (amoxicillin/clavulanate)
surgical management
abscesses - incision and drainage with washout
treatment of chronic disease - Bascom procedure or the Karydakis procedure
what is a perianal fistula ?
aka fistula-in-ano
refers to an abnormal connection between the anal canal and the perianal skin
what causes perianal fistula?
typically occurs as a consequence of perianal abscess
other risk factors include: IBD systemic disease - TB, DM, HIV history of trauma in the anal region previous radiation therapy to the anal region
