GI 2 Flashcards
What are some mechanisms of intestinal obstruction?
Mechanical
True (intraluminal/extraluminal)
Functional - paralytic ileus
What can cause intestinal obstruction?
Tumour - carcinoma, lymphoma
Diaphragm disease
meconeum ileus
gallstone ileus
crohn’s
diverticulitis
hirschprung’s
adhesions (most common)
volvulus
How does small intestinal obstruction present?
pain - colicky then diffuse, pain higher than in large bowel obstruction
profuse vomiting that follows pain
less distension than LBO
nausea
tenderness = strangulation
How would you investigate a SBO?
Abdo X-ray - partial SBO = gas throughout the abdomen and into the rectum
complete SBO = no distal gas, staggered air-fluid levels
FBC
Urea
Electrolyte panel
Abdo CT
How would you a treat a SBO?
Emergency laparotomy plus fluid resus
Preoperative antibiotic prophylaxis - ampicilin + gentamicin
morphine
How would a large bowel obstruction present?
on av. 5 days of symptoms - present slower and later than in SBO
abdo pain that is more constant than in SBO
bowel sounds normal then quiet
palpable mass
late vomiting
constipation
fullness/bloating/nausea
How would you investigate a LBO?
FBC
serum electrolytes
renal function
serum amylase/lipase
erect chest x-ray
plain abdo x -ray- gaseous distension of large bowel, kidney shape seen in volvulus
How would you manage a LBO?
emergency surgery
What causes LBO?
colorectal malignancy
volvulus
What is a pseudo-obstruction?
clinical picture mimicking obstruction but with no mechanical cause
What are some causes of pseudo-obstruction?
intra-abdominal trauma
pelvic, spinal and femoral fractures
postoperative states
intra-abdominal sepsis
pneumonia
drugs (opiates, antidepressants)
metabolic disorders (electrolyte disturbances, malnutrition)
What are the 3 main types of bowel ischaemia?
acute mesenteric ischaemia
chronic mesenteric ischaemia (intestinal angina)
ischaemic colitis (chronic colonic ischaemia)
Where is blood supply to colon come from?
What are watershed areas which are most susceptible to ischaemia?
inferior and superior mesenteric arteries
splenic flexure and caecum
What is acute mesenteric ischaemia? What are the causes?
bowel ischaemia affecting the small bowel
caused by superior mesenteric thrombosis
How does acute mesenteric ischaemia present?
Acute severe abdominal pain - constant, central or around right iliac fossa
No abdo signs
Rapid hypovolaemia - shock
How would you investigate ischaemic bowel disease?
CT - first line
sigmoidoscopy or colonoscopy
FBC
Chemistry panel - acidosis, uraemia, elevated creatinine
Coag panel - underlying prothrombotic disorder
ABG/lactate level
ECG - arrthmias or acute infarct that may be cause
Erect CXR - free air if perforation present
Abdo x-rays
How would you manage iscahemic bowel disease when there is no sign of infarction, perforation or peritonitis?
Supportive - NG tube, NBM, O2
Empiric Abx - ceftriaxone and metronidazole
SMA Embolus - open embolectomy or arterial bypass +/- bowel resection
Papaverine - antispasmodic
Chronic mesenteric ischaemia - medical optimisation + surgival systemic mesenteric bypass
Non-acute colonic ischaemia - segmental colectomy
Non-acute colonic ischaemia - segmental colectomy
What are the causes/RFs of Ischaemic Colitis?
Low flow in the inferior mesenteric artery territory
thrombosis
emboli
decreased cardiac output
drugs - oestrogen, antihypertensives, vasopressin
surgery
vasculitis - SLE, sickle cell
Coag disorders
COCP
How would ischaemic colitis present?
sudden onset lower left side abso pain
bright red blood without diarrhoea
signs of shock
What are some causes of haemorrhoids?
constipation
diarrhoea
congestion - pelvic tumour, pregnancy, portal hypertension
anal intercourse