Abdominal castrophies, pain and imaging Flashcards
Describe the sensory innervation to parietal and visceral peritoneum
Parietal is supplied by the same nerve that supplies the skin above it (somatic innervation). Visceral pain is sensed by the sympathetic fibres
In what circumstances can somatic pain be referred?
When the stimulus is in the proximal part of the somatic nerve, the pain will be referred to the distal dermatome of that nerve
Give two examples of somatic referred pain
- In SHINGLES, when the virus reactivates it irritates the proximal nerve, and so pain is referred to whatever root is affected. It is often mistaken for appendicitis, as it may start at umbellical region of T10 and then move to RIF as the shingles spreads and then the rash doesnt appear till later - In RIGHT LOWER LOBE PNEUMONIA the pain can initially be felt in the right illiac fossa
Explain why visceral pain is referred
The visceral afferent pain fibres follow sympathetics back to their spinal cord roots. The CNS therefor perceives the pain as coming from the somatic portion of the body supplied by that spinal segment (dermatome). You therefor get a generalised pain around the region of that dermatome
What can cause visceral pain?
Stretching Abnormally strong contraction Inflammation Ischaemia
Where can lung and diaphragm pain be refered to? and why?
The shoulder/ neck- because its pain afferents travel on the splanchnic nerve (C3,4,5) and pain is mistaken for coming from somatics innervating C3 and 4- the neck region
Describe gall bladder pain
sharp, fast onset Starts centrally (epigastric), then irritates parietal peritoneum and so is localised to the right, then irritates diaphragm and so may radiate to shoulder
Describe the difference between large bowel colic pain and small bowel colic pain
Small bowel more painful and frequent- every 90 s. Large bowel waves of pain every 4/5 mins.
Where can kidney/ ureteric pain be felt
Anywhere in lower abdomen as well as down lateral theigh and scrotum. It is very severe theyll probably be rolling around on the floor.
Describe the pain of peritonitis
Severe pain all over abdomen, if the diaphragm is affected it will radiate to shoulder tip. The pain is worse on moving the diaphragm so breathing tends to be shallow. It will be tender to touch. In the early stages they may only have rebound tenderness
What are the 4 main categories of abdominal catastrophies
Blood loss Perforation of a viscus Autodigestion of a viscera/ the peritoneum Gut ischeamia (Acute cholangitis doesnt really fit a class tho)
What could cause bleeding into the gut? (3)
Bleeding oesphageal varices Bleeding peptic ulcers Bleeding diverticular disease
What are the 3 biggest signs of GI bleeding?
Haematemesis- vomiting blood (upper GI bleed) Malaena- metabolised blood in stools making then dark and smelly (Bleed can be anywhere above caecum) Haematochezia- red blood in stools (rectal/ colon bleeding)
What artery is commonly eroded and the source of bleeding for duodenal ulcers
The gastroduodenal artery (erodes through posterior wall)
Why may a pts serum urea be high if they have an upper GI bleed?
Large protein meal is presented to stomach, protein converted to urea by liver, so urea increases. The higher the urea the greater the bleed. If serum creatinine is high, its probably due to kidney failure instead.
What is the most common cause of retroperitoneal bleeding?
Ruptured abdominal aeortic aneurysms. If on anticoagulants it may be due to torn retroperitoneal veins
If someone with a ruptured AAA doesnt die suddenly, how will they present?
severe back/ central pain Shock sudden collapse
What may cause bleeding into the peritoneum?
Ruptured ectopic pregancy.
Describe the presentation of someone with a ruptured ectopic pregnancy
- Reproductive age - Lower abdo pain - Vaginal bleeding - Collapse/ shock - left shoulder tip pain when lying down
What is pointed at in the image shown?
Diverticular
What are the two most common cause of a perforated viscus?
Peptic ulcers
Perforated diverticular disease
What are the consequences of a perforated peptic ulcer and a perforated diverticular?
ulcer- gastric contents enter peritoneal-> chemical peritonitis (10% mortality)
Diverticular- bacteria and gut contents enter peritoneum rapidly leading to sepsis (50% mortality)
What investigation can be done which can indicate a perforated viscus?
Erect CXR- see gas under diaphragm
What are the general signs of a perforated viscus?
Severe generalised abdo pain
shallow breathing
hypovolaemic
septic
Give common causes of small and large bowel obstruction (3 each)
Small= adhesions, hernias, volvulus, carcinomas
Large= carcinomas, volvulus, diverticular disease
What is the commonest cause of acute gut ischaemia?
Embolism from A. Fib
How may acute gut ischaemia present?
severe abdo pain and tenderness, toxic, hypertensive, very high WBC
How is ischaemic bowel treated?
Urgent laparotomy to remove dead bowel. It carries a 90% mortality rate.
When is an abdominal x ray implicated? (4)
- suspected bowel obstruction
- flare ups of IBD
- Forgein bodies
- Suspected calcification
What features of an AXR suggest small bowel obstructiona and what suggests large bowel obstruction?
Small bowel- presence of valvulae conniventes and diametes of >3cm, central location
large bowel- diametes of >6 cm/ >9cm at caecum and presence of haustra, peripheral location
What is shown in the image
Small bowel obstruction
What is in the image shown
Large bowl obstruction
What is in the image shown
Sigmoid volvulus- coffebean sign
Where is the most common place for an intestinal volulus and why
sigmoid colon, it has a long mesentary which can easily become twisted on itself
What is toxic megacolon
Breakdown of the colon wall, with impingment on the myenteric plexus, resulting in loss of the smooth muscle tone, dilation and pressure build up. It is usually secondary to UC, or rarely crohns or C. Diff.
What is shown in the image?
Toxic megacolon- this person aslo has lead pipe colon due to their UC
What calcifications can be seen in an AXR?
Renal caliculi
vascular calcification
pancreatic calcification following chronic inflammation
How can swallowing mechanisms, strictures ect be imaged?
Barium swallows, barium enemas
What is a virtual colonoscopy?
Where indivulal images from CT scanners are used to create a 3D virtual image of the colon. This saves the pt having to have a colonoscopy for cancer- 95% of which are negative
What are the Avd and DisAdv of MRI?
No radiation
High resolution
Takes long time
Clostrophobia
