Acute Abdo Pain Imaging Flashcards
what are the most common causes of abdo pain
non specific appendicitis bowel obstruction urinary system diverticulitis
what are the imaging tools for the abdomen
primary:
- X-ray (erect for gas under diaphragm)
- CT
- USS
secondary
- MRI (take 30-45 mins)
- fluoroscopy (not done as much these days
what conditions can erect abdo c ray exclude
bowel obstruction/ perforation
what can USS image
solid organs, free
fluid, aorta, pelvis
Bowel – occasionally helpful
what is more useful for abdo x ray or USS
USS
what is the most sensitive test in the abdomen
CT
what are the cautions of CT
radiation exposure renal impairment (contrast)
what is MRI good for
soft tissue delineation, esp in pelvis
what abdo conditions is MRI used in
used as second line test for:
- hepato-biliary
- small bowel
- pelvis
what are the presenting features of an acute appendicitis
periunbilical pain
nausea
vomiting
localised to RIF
what Ix for appendicitis
USS
CT is this is inconclusive
swelling and oedematous fluid surrounding it, will be inflamed and fluid filled on USS
what are the complications of diverticulitis
abscess
obstruction
perforation
fistulae
what imaging for acute diverticulitis
plain x ray to exclude obstruction/ perforation
CT
will see soft tissue thickening, inflamed bowel
what can USS not see through
gas- so if you have a retrocaecal appendix wont be able to see it
what is acute cholecystitis almost always secondary to
gallstones
what is the diagnosis of acute cholecystitis based on
one local sign of inflammation (RUQ pain etc)
one sign of inflammation (fever, WCC, CRP)
confirmatory imaging
what imaging for acute cholecystitis
USS (will see gallstones, CB wall thickening, local fluid. Gall bladder should just be black, in acute cholecystitis will have blood/ pus surrounding the stone, shows up as grey)
CT
MRI if biliary tree dilation
MR cholanfiopancreatography (MRCP) shows stones in GB/ bile ducts
how is a paracolic abscess treated
needs to be drain (can be caused by perforation)
should there usually be gas in the urinary bladder
no
what do gallstones look like on USS
are echogenic- white, will cast black shadow behind it
what is the treatment for acute cholecystitis
medical/ conservative
ERCP to clear out bile duct
surgery to remove gall bladder
what is emphysematous cholecytsitis
when there is air in gallbladder wall
happens in diabetics
what are the common causes of small bowel obstruction
adhesions, camcer, herniae, gallstone ileus
what are the symptoms of small bowel obstruction
vomiting, pain, distention
what are the signs of small bowel obstruction
increased bowel sounds, tenderness, palpable loops
what does imaging do in small bowel obstruction
defines site, cause, severity, complications (perforation/ ischaemia)
what investigations for small bowel obstruction
initial- X ray (good, can miss fluid filled loops)
CT (v sensitive and specific, adhesions not seen)
how can you tell small from large bowel
small bowel have valvulae conniventes lines which go all the way from one side to another
large bowel has haustra but these dont go the whole way across
what are the common causes of large bowel obstruction
colorectal cancer
volvulus
diverticulitis
what imaging for large bowel obstruction
X ray - may not be helpful, may not diagnose underlying disease
CT best- shows transition point, underlying mass, state of caecum, distant disease
what are the causes of bowel perforation
common:
- ulcer
- diverticular
less common
- cancer
- ischaemia
what imaging for peforation
x ray -may miss small pockets of gas -doesn't show site origin CT -high sens and spec -shows free fluid -shows clues to site of origin: distribution gas, defect in wall, local inflammation
what is riglers sign
when you can see both sides of the bowel wall as the gas outside (happen when perforated) acts as a contrast
is a pathological sign
when does bowel ischaemia develop
when it receives less than 10% of cardiac output
what causes bowel ischaemia
arterial occlusion
venous occlusion
non occlusive hypoperfusion
what are the signs and symptoms of bowel ischaemia
severe abdo pain, very acute onset
vomiting, diarrhoea, distention
boderline amylase, raised WCC, acidotic
what are the differentials of bowel ischaemia
perforation, pancreatitis, obstruction, diverticulitis
what imaging for bowel ischaemia
biphasic CT
- modality of choice
- shows site of occlusion and length of bowel affected
when do you gas in portal vein
very bad- happens in bowel ischaemia
what is emergency EVAR
endovascular aortic repair
USS is used first for pain where
RUQ, RIF
summarise the role of CT in the abdomen
primary imaging technique for acute abdo pain except for acute cholecystitis/ appendicitis
what preparation for a gall bladder USS- why
fast them so you can get their gallbladder to distend.
If they are fasted, there is less gas in the duodenum so you are more likely to see the CBD
when is the common bile duct dilated
when more than 5mm
what are the main complications of pancreatitis
necrosis, formation of a pseudocyst
what is seen on CT in pancreatitis
oedema, swelling
what vessels are at risk in pancreatitis
splenic vein- thrombosis
branches of gastroduodenal artery- erosion (haemorrhage due to pseudoaneurysm formation)
what is MRCP
a non invasive way of looking at the billiary tree (magnetic resonance cholangiopancreatography)
what is ERCP
endoscopy retrograde cholangiopancreatography - combines the use of endoscopy and fluoroscopy to diagnose and treat certain problems of the biliary or pancreatic ductal systems
how are pancreatic pseudocysts treated
drained percutaneously under CT guidance
what is a pseudocysts
has a non epithelialised cysts
what is the largest branch of the circle of willis
MCA- runs horizontally
what colour is fluid on USS
black
what muscles are activated when you put your hands on your knees to catch your breath
pec minor and serratus anterior (attach to the ribs and scapula, this position allows the accessory muscles of respiration to be used more effectively- not being used to maintain posture)
via what does the ICA enter the skull base
carotid canal
what can be damaged in a supracondylar fracture of the humerus
ulnar nerve
brachial artery
what nerve injury results in anaesthesia of the lateral skin of the forearm
lateral cutaneous nerve of the forearm (is a branch of the musculocutaneous nerve)
what vertebral level does the aortic arch begin and end
T4/5
