Session 9: GI Emergencies Flashcards
What is peritonitis?
Inflammation of the serosal membrane that lines the abdominal cavity.
How can peritonitis occur?
The peritoneal cavity is normally a sterile environment with no bacteria in it.
Peritonitis can occur spontaneously also known as primary peritonitis or in the breakdown of the peritoneal membranes leading to a foreign substance entering the cavity which is known as secondary peritonitis.
What is spontaneous bacterial peritonitis (SBP)?
An infection of ascitic fluidthat cannot be attributed to any intra-abdominal, ongoing inflammatory, or surgically correctable condition. I.e. it cannot be attritbuted to another condition.
When is SBP most commonly seen?
In patients with end stage liver disease like a cirrhotic liver.
What is ascites?
A pathological collection of fluid within the peritoneal cavity.
Symptoms of SBP.
Abdominal pain, fever and vomiting.
However the symptoms are commonly mild.
How is SBP diagnosed?
Aspirating ascitic fluid where a neutrophil count over 250 cells/mm3
What is secondary peritonitis?
A result of an inflammatory process in the peritoneal cavity secondary to inflammation, perforation, or gangrene of an intra-abdominal or retroperitoneal structure.
Common causes of secondary bacterial peritonitis.
Peptic ulcer disease that perforates
Appendicitis that perforates
Diverticulitis that perforates
Volvulus
Non-bacterial causes of secondary peritonitis.
Tubal (ectopic) pregnancy that bleeds (this is because the peritoneal cavity is not entirely closed in females)
Ovarian cyst
Cancer
Blood is highly irritant to the peritoneal cavity.
Clinical presentation of peritonitis.
Abdo pain that can come gradually or acutely.
Diffuse abdo pain is common in perforated viscera.
The patients often lie very still as any movement will make the pain worse.
Knees flexed
Shallow breathing
Treatment of peritonitis.
Control the infectious source
Surgery if there is perforation
Eliminate bacteria and toxins via antibiotics.
Maintain organ system function
What is bowel obstruction?
A mechanical or functional problem that inhibits the normal movement of gut contents.
It can either effect the large or small intestines.
Common causes of bowel obstruction in children.
Intussusception
Intestinal atresia
Pyloric stenosis
Common causes in adults with bowel obstruction.
Adhesions
Incarcerated hernias
What is intussusception?
When one part of the gut tube telescopes into an adjacent section.
It is usually small bowel that is proximal that telescopes into a distal large bowel.
They can extend as fair to even prolapse out of rectum.
Clinical presentation of intussusception.
Abdo pain
Vomiting
Haematochezia
Mucous in the blood of the stool
Oedema when lympathic and venous drainage gets impaired.
Treatment of intussusception.
Air enema
Surgery
Causes of intussusception.
Potential motility issues
Meckel’s diverticulum
Enlarged lymph nodes
Symptoms of small bowel obstruction.
Nausea and vomiting are the most common early symptoms.
Abdominal distention
Absolute constipation are late symptoms.
What is small bowel obstruction commonly caused by?
Intra-abdominal adhesions
What are intra-abdominal adhesions?
Abnormal fibrous bands between organs or tissues or both in the abdominal cavity that are normally separated.
When might intra-abdominal adhesions occur?
Arise after more than 50% of abdominal surgeries.
Usually the greater omentum is involved (80%), bowel is involved in 50%.
There is damage to mesothelium and capillary bleeding can lead to exudation of fibrinogen.
Give other small bowel obstruction causes.
Hernias (can narrow the lumen enough to cause obstruction)
Inflammatory bowel disease (Crohn’s) where repeated episodes of inflammation/healing causes narrowing.
Diagnosis of small bowel obstruction.
History - abdo pain that is crampy and intermittent. Make sure to ask how frequent the cramp is.
Physical examination - abdo distension, increased/absent bowel sounds, hernia.
Imaging
What demography does large bowel obstruction usually affect?
Elderly
Common causes of large bowel obstruciton.
Colon cancer
Diverticular disease
Volvulus (sigmoid or caecal)
Common symptoms of large bowel obstruction.
Change in bowel habits (cancer)
Abdominal distension
Crampy abdominal pain
Nausea and vomiting (late)
In what instances of large bowel obstruction are the symptoms gradual and when are they abrupt?
Volvulus are abrupt
Cancer is usually gradual
What is a volvulus?
When a part of the colon twists around its mesentery and result in obstruction of that part.
What part of the colon is most commonly twisted resulting in a volvulus?
Sigmoid colon
Can also happen in the caecum and technically anywhere.
Causes of volvulus.
Can result from an overloaded sigmoid colon where the extra mass predisposes elongation of the sigmoid.
A high fibre diet can also lead to sigmoid overload and twisting.
How does small and large bowel obstruction differ?
Small - more common in younger age
Large - more common in elderly
Vomiting presents early in small and late in large
Constipation presents early in large and late in small.
The abdominal pain and cramps are frequent in small (3-4 min) and not as frequent in large (10-15 min)
In which patients is acute mesenteric ischaemia common in?
More common in females and if you have a history of peripheral vascular disease.
Causes of acute mesenteric ischaemia.
Acute occlusion (70%) (Arterial embolism of SMA)
Non occlusive mesenteric ischaemia (20%) Like low cardiac output.
Mesenteric venous thrombosis (5-10%)
Clinical presentation of acute mesenteric ischaemia.
Can be difficult to establish as the symptoms can be fairly non-specific.
Abdo pain disproportionate to clinical findings that comes on 30 minutes after eating and last 4 hours.
Nausea and vomiting
Where is it common to have pain in acute mesenteric ischaemia?
Left sided pain.
Why is it common to have left sided pain in acute mesenteric ischaemia?
Because the blood supply to the splenic flexure is most fragile.
Investigations of acute mesenteric ischaemia.
Blood tests to check for metabolic acidosis and increased lactate levels.
Erect CXR to check for perforation
CT angiography with intravenous contract.
Treatment of acute mesenteric ischaemia.
Surgery with bypass graft
Thrombolysis and angioplasty
What peptic ulcers are most common?
Duodenal ulcers in the first part of the duodenum.
Artery that can be compromised in duodenal ulcers.
Gastro-duodenal artery.
Where are common sites of gastric ulcers?
Lesser curver and antrum.
What artery can be compromised in gastric body ulcers?
Splenic artery
Gives causes of major upper GI bleeding
Peptic ulcers and oesophageal varices.
Causes of oesophageal varices?
Portal hypertension like portal vein thrombosis, cirrhosis, schistosomiasis, hepatic vein thrombosis.
Explain the drainage of the oesophageal veins in case of oesophageal varices.
Portal drainage into left gastric vein and draining into portal vein.
Systemic drainage into azygous veins and into SVC.
Treatment of oesophageal varices.
Endoscopy with band ligation.
What can be done if the bleeding is not controlled by the band ligation?
TIPS which is transjugular intrahepatic portosystemic shunt.
Explain TIPS.
An expandable metal is placed within the liver and bridges the portal vein to an hepatic vein.
This decompresses the portal vein pressure and there is a reduction in variceal pressure.
There is also a reduction in ascites.
Drug treatment of upper GI bleed in case of oesophageal varices.
Terlipression that reduces portal venous pressure.
Explain abdominal aortic aneurysm.
A permanent pathological dilation of the aorta.
What is the most commonly adopted threshold of an AAA?
A diameter of 3 cm or more.
A diameter of >1.5 times the expected anteroposterior diameter of the segment.
Where are most AAAs found?
What are such AAAs called?
Originate below the renal arteries (90%)
Infrarenal AAAs
Explain how AAAs occur?
Degradation of the tunica media of the arterial wall.
The media with smooth muscle cells and elastin + collagen loses it elastin and collagen and the lumen gradually starts to dilate.
Risk factors of AAAs.
Male
Inherited risk like Marfan’s e.g.
Increasing age
Smoking leading to peripheral athersclerotic vascular disease.
Clinical presentation of AAAs.
Usually asymptomatic until an acute expansion or rupture.
It can cause symptoms by compressing other adjacent structures like the stomach, bladder or vertebra causing nausea, urinary frequency and back pain.
However it can feel like a pulsating mass or feeling in the stomach.
When does AAAs usually become symptomatic?
When they rupture.
Usual presentation of ruptured AAA.
Abdo pain +/- flank and groin pain. (Can be confused with pancreatitis)
Back pain
Pulsatile abdo mass
Transient hypotension
Syncope
Sudden cardiovascular collapse.
Diagnosis of AAAs.
Physical examination where a presence of a pulsatile abdo mass might be felt.
Ultrasonography
CT
Plain X-ray
Treatment of AAAs.
Non-surgical
Surgery
Give non-surgical treatments of AAAs.
Smoking cessation
Hypertension control
Surveillance
When do you start surveillance of AAAs?
At 3cm diameter.
When would you start surgery of AAAs?
When the AAA has grown to more than 5.5 cm.
What types of surgery can be done in AAAs?
Endovascular repair or open surgical repair.
Explain endovascular repair of AAAs.
Relining the aorta with an endograft and put in a stent. This is usually done via the femoral artery.
This allows blood to bypass the aneurysm.
Explain open surgical repair of AAAs.
Clamp the aorta and then open the aneurysm to remove thrombus and debris.
Then suture in a synthetic graft to replace the diseased segment.
