S9 L1 GI Emergencies Flashcards
What is the key feature of peritonitis?
- Diffuse abdominal pain that will be sudden if perforated viscus
- Patient will often lie very still and any movement is very painful. Shallow breathing and flexed knees
- Control the infectious source, eliminate bacteria and support organs
What is the difference between primary and secondary peritonitis?
Primary: spontaneous infection of ascitic fluid. vomiting, abdominal pain and fever
Secondary: results from inflammatory process leading to perforation or gangrene of abdominal viscera, e.g appendicitis, peptic ulcer disease, ovarian cyst, tubal pregnancy
How does a cirrhotic liver lead to ascites?
- Portal hypertension increases hydrostatic pressure in the veins draining the gut
- Decreased liver function so less albumin production so lower oncotic pressure holding in fluid
What are the common causes of bowel obstruction?
Adults: post op adhesions, incarcerated hernias
Children: intussusception, intestinal atreisa, meconium ileus
What is intussusception, how does it cause bowel obstruction and how do you treat it?
- One segment of the bowel telescopes into the other, usually due to a mass like an enlarged lymph node or Meckel’s diverticulum
- Lymphatic and venous drainage can be impaired and you get oedema and infarction
- Abdominal pain, vomiting, haematochezia
- Air enema or surgery
What is the common presentation of small bowel obstruction?
- Start sudddenly with peri-umbilical pain, nausea and vomiting
- Abdomen tender and distended
- High pitched bowel sounds
- Late absolute constipation
- Usually due to abdominal adhesions
How can we diagnose a small bowel obstruction?
- History of abdominal pain
- Physical examination: high pitched bowel sounds, presence of hernia, abdominal distension
- Image with x-ray to see distended loops
What is the common causes of large bowel obstruction?
- Colorectal cancer
- Volvulus
- Strictures from diverticulitis
Most occur distal to splenic flexure
What are some common symptoms of large bowel obstruction?
- Periumbilical or suprapubic pain
- Abdominal distension and pain
- Nausea/vomiting
- Constipation then diarrhoea
Where are the most common areas for a volvulus to occur?
- Caecum
- Sigmoid
Overloaded sigmoid from constipation can twist on its axis
What are the differences between small and large bowel obstruction?
- Small bowel tends to be younger age group than large
Who is more at risk of acute mesenteric ischaemia and what can it be caused by?
- More common in females, elderly and peripheral vascular disease
Caused by:
- Emboli in SMA
- Arterial or venous thrombosis
- Vasculitis
- Vasoconstriction
How does acute mesenteric ischaemia present?
- Difficult to detect
- Abdominal pain disproportionate to clinical findings
- Fever, diarrhoea, nausea and haematochezia
- Pain often left sided as splenic flexure is fragile
How would you investigate and treat a suspected acute mesenteric ischaemia?
- Blood test for metabolic acidosis/increased lactate levels
- Erect CXR for perforation
- CT angiography
- Surgery to resect ischaemic bowel
- Surgical embolectomy
- Thrombolytic agents
What are the common causes for upper GI bleeding?
- Peptic ulcers (gastric antrum/lesser curve > duodenal)
- Varices
Most upper GI bleeds stop spontaneously
What is the main cause of oesophageal varices?
- Portal hypertension
- 90% of people with this will develop varices and 30% of these will bleed
How can we treat upper GI bleeding?
Variceal: vasopressin agonist called terlipressen that reduces portal vein pressure
Other: endoscopy with clips, coagulation/thrombin. PPIs are given after
If we cannot control oesophageal varices bleeds by band ligation or terlipressin, what else can we do to intervene?
Bypasses the liver
What is the definition of an AAA?
Dilation of the aorta up to 1.5 times expected, usually over 3cm in diameter (infrarenal aorta should be 1.5cm)
Due to a breakdown of the media in the arterial wall
What are the risk factors for an AAA?
- Male
- Over 65
- Smoke
- Peripheral atherosclerotic disease
Most are asymptomatic and found incidentally
What are the symptoms of an AAA about to rupture?
- Back and abdominal pain
- Pulsatile mass in abdomen
- Signs of cardiovascular collapse, e.g syncope, transient hypotension
How do you diagnose an AAA?
- Physical examination
- Ultrasonography
- CT
- Plain x-rays as aneurysm may have calcified
How do you treat an AAA?
Unruptured: endovascular stent graft, smoking cessation, surveillance
Ruptured: emergency resuscitation, clamp the aorta and suture in a synthetic graft
Why does a patient have a normal blood pressure when their aorta initially ruptures?
Aorta is in the retroperitoneum which is a small space so the blood has a tamponade effect at first
How does C.Diff cause diarrhoea and why is it such an issue in hospitals?
- Toxin A (enterotoxin stimulating fluid secretion) and toxin B (cytotoxin)
- Spores, need a deep cleaning, doesn’t wash off with alcohol gel
- Need to isolate patients, give them fluid and oral metronidazole and stop any other antibiotics
At what vertebral level is this CT taken?
T12 - can see the coeliac trunk!
What type of hernia might be precipitated by a weakened conjoint tendon?
Direct
Which branch of the Coeliac trunk (Labelled CT) supplies blood to the lesser curve of the stomach?
- Left gastric
- Look for Mercedes sign
Where is the hepato-renal recess?
- Betweent the inferior surface of the liver and the kidney
- Shouldn’t normally be filled with fluid
How can you tell where the caudate lobe is on the inferior view of the liver?
- GQ magazine so quadrate next to gallbladder so caudate is the other one
Which part of the stomach has the highest density of G cells?
What structures lie in the free edge of the lesser omentum?
- Hepatic artery
- Hepatic portal vein
- Common bile duct
What are the boundaries of the lesser sac?
Anterior: lesser omentum and posterior stomach
Posterior: pancreas
(google rest)
What separates the supra and infracolic compartments?
Transverse mesocolon
GW:
- Which area of the GI tract does Crohn’s usually start?
- Most common extra-interstinal probelms associated with IBD?
- What causes the cobblestone appearance in Crohn’s?
- What histological features might you see on a biopsy of the gut wall taken from a patient with Ulcerative colitis?
- Explain why CT and MRI scans are less useful for investigating UC compared to Crohn’s?
- Terminal ileum
- Joint pain - Arthritis
- Muscosal oedema (‘middle bits’), surrounded by ulcers
- Absess in crypts, crypt distortion. Chronic inflammatory infiltrate in lamina propria. Darker, crowded nuclei. Exudate in lamina propria
- Crohn’s has more obvious changes on CT and MRI, e.g. strictures, fistulas UC - changes purely on mucosa, not as obvious - investigate via colonoscopy
GW:
- Explain why osmotic diarrhoea improves when you stop eating but secretory diarrhoea continues?
- Explain why (referencing the anatomy of the appendix) Appendicitis can present differently in different people
- Briefly describe the factors that collectively enable us to be continent with regard to faeces
- Explain why tenesmus is potentially a red flag symptom?
- Explain why the pain associated with (classic) Appendicitis moves location in the abdomen as the disease process develops?
- Explain why you get pain with external haemorrhoids but not with internal haemorrhoids?
- Osmotic - gut lumen contents, pulls water in e.g. lactose intolerance, anything stopping you from absorbing Secretory - affecting the pump (issue with epithelium), infective cause
- Appendix position is different in different people. E.g. in people with pelvic and retro-cecal - may not get right iliac fossa pain, as when enlarged, it doesn’t come in contact with parietal peritoneum (or take longer to get the pain)
- Internal and external feaces, Firm, bulky faeces, Distension of rectum, Anal cushion, Puborectalis, Normal anal-rectal angle
- Mass in the rectum (same effect as if feaces was there…). Feeling of not fully evacuating the bowels - feeling of fullness could be caused by a mass
- Inflammatory:
• Visceral afferent neurones - Beginning - gets T10 (where the visceral afferents come in from the appendix)
• More inflammed - ends up hitting the parietal peritoneum (somatic nerves innervate this), then more localised pain to the position of the appendix - External haemorrhoids - below dentate line, somatic nerves Internal haemorrhoids - above dentate line, visceral afferent (splanchnic nerves)
