Gastrointestinal Emergencies Flashcards
What is peritonitis?
Inflammation of the serosal membrane that lines the abdominal cavity
Types of peritonitis
- Primary: spontaneous + not as a result of pathology in another organ
- Secondary: breakdown of the peritoneal membranes leading to foreign substances entering cavity
What is the peritoneal cavity?
Space between the visceral + parietal layers of peritoneum
What are the subdivisions of the peritoneal cavity?
Greater sac
Lesser sac
What is spontaneous bacterial peritonitis?
- Primary peritonitis
- Infection of asitic fluid that cannot be attributed to any intra-abdominal, ongoing inflammatory or surgically correctable condition
Presentation of spontaneous bacterial peritonitis
Variable
Abdominal pain
Fever
Vomiting
Investigation of spontaneous bacterial peritonitis
Aspirating ascitic fluid
Neutrophil count >250 cells/mm3
Bacterial causes of secondary peritonitis
- perforated peptic ulcer disease
- perforated appendicitis
- perforated diverticulitis
- post surgery
Non bacterial causes of secondary peritonitis
- tubal pregnancy that bleeds (ruptured ectopic pregnancy)
- ovarian cyst
Clinical presentation of secondary peritonitis
- abdominal pain
- lie very still as movement makes pain worse
- rebound tenderness
- guarding (abdominal wall muscles tense when going to exam)
Treatment of secondary peritonitis
- surgery: control infectious source
- antibacterial therapy: eliminate bacteria
- intensive care: maintain organ system function
What is a bowel obstruction?
Mechanical or functional problem that inhibits the normal movement of gut contents
Common causes of bowel obstructions in children vs adults
children:
- intussusception
- intestinal atresia
adults:
- adhesions
- incarcerated hernias
What is intussusception?
When one part of the gut tube telescopes into an adjacent section
Clinical presentation of intussusception
Adnominal pain
Vomiting
Haematochezia (fresh red rectal bleeding)
Treatment of intussusception
Air enema (reverses telescoping)
Surgery
What is haematochezia?
Fresh red rectal bleeding
Causes of small bowel obstruction
- intra abdominal adhesions
- hernias
- Crohn’s disease
What are intra-abdominal adhesions?
Abnormal fibrous bands between organs, tissues or both in abdominal cavity that are normally separate
Clinical presentation of small bowel obstruction
- nausea + vomiting (bilious) (early on)
- abdominal colicky pain + distension
- absolute constipation (later on)
What is colicky pain?
Comes + goes in waves
**»
Diagnosis of small bowel obstructions
- History
- Physical exam: abdominal distension, presence of hernias, high pitched tinkling bowel sounds
- Imaging
Who does large bowel obstruction more commonly occur in?
Older patients
Causes of large bowel obstructions
Colon cancer (most common)
Diverticular disease
Volvulus - sigmoid, caecal
What is a closed loop obstruction?
There is a complete obstruction distally and proximally in the given segment of the intestine
Presentation of large bowel obstruction
- symptoms appear gradually if cancer + abruptly with volvulus
- change in bowel habit (constipation) (early)
- abdominal distension
- cramps abdominal pain
- nausea + vomiting (late)
Diagnosis of large bowel obstruction
History
Physical exam
Imaging
what is a volvulus?
Part of the colon twists around its mesentery
Where are volvulus most likely to occur?
Sigmoid colon
Then caecum
What is a risk factor for volvulus?
High fibre diets
Compare the symptoms of small and large bowel obstruction
Small:
- colicky pain more frequently
- vomiting occurs early
- constipation occurs later
Large:
- vomiting occurs later
- constipation occurs earlier
What imaging is used to determine the cause of an obstruction?
CT
What is acute mesenteric ischaemia?
Symptomatic reduction in blood supply to GI tract
Who is acute mesenteric ischaemia more common in?
Females
History of peripheral vascular disease
Types of acute mesenteric ischaemia
Arterial compromise:
- acute occlusion: arterial embolism in SMA or vasculitis
- non occlusive mesenteric ischaemia: low cardiac output
Venous compromise:
- mesenteric venous thrombosis
Clinical presentation of acute mesenteric ischaemia
- mainly in elderly patients with CV risk factors
- abdominal pain (30mins after eating)
- nausea + vomiting
- pain often on left side
Where is pain often located in acute mesenteric ischaemia?
Why?
Left sided
Blood supply to splenic flexure is most fragile
(Watershed area)
Investigations of acute mesenteric ischaemia
- blood tests: metabolic acidosis + increased lactate levels
- erect chest X ray (check for perforation)
- CT angiography
Treatment of acute mesenteric ischaemia
- resection of ischaemic bowel
- thrombolysis/angioplasty
Where are peptic ulcers most common?
D1
Common site of gastric ulcers
Lesser curve
Antrum
What could cause a major upper GI bleed?
Peptic ulceration
Varices
What vessel is at risk of damage if a duodenal ulcers perforates?
Gastroduodenal artery
Why do oesophageal varices form?
Portal hypertension
What is the normal pressure in the portal vein?
5-10 mmHg
Venous drainage of the oesophagus
Upper 2/3: oesophageal veins > azygous vein > SVC
Lower 1/3: left gastric vein > portal vein
Treatment of oesophageal varices
- Endoscopy + band ligation
- Blood transfusion if bleeding
- terlipressin: reduces portal venous pressure
What is abdominal aortic aneurysm?
Permanent pathological dilation of the aorta with diameter >1/5 x the expected diameter
What drug is used to treat variceal bleeds?
Terlipressin
Reduces portal venous pressure
Location of most AAA
Below renal arteries
How does AAA occur?
- Degradation of the elastin + collagen in media layer of arterial wall
- lumen gradually dilates
risk factors of AAA
Male
Family history
Increase age
Smoking
Clinical presentation of ruptured AAA
- asymptomatic until rupture
- abdominal pain radiating to back
- pulsation abdominal mass
- transient hypotension > syncope
Diagnosis + investigation of AAA
- physical exam: presence of pulsation abdominal mass
- ultrasonography
- CT
- X- ray if calcified
Treatment of AAA
- smoking cessation
- hypertension control
- surveillance of AAA (>5.5cm refer to vascular surgeons)
- endovascular repair
- open surgical repair
What are the surgical treatment of AAA?
Endovascular repair
Open surgical repair
Outline endovascular repair of AAA
Relining the aorta using an endograft inserted through the femoral artery
Outline open surgical repair of AAA
- Clamp aorta
- Open aneurysm (remove thrombus + debris)
- Suture in synthetic graft to replace diseased segment
Who is spontaneous bacterial peritonitis most commonly seen in?
Patients with end stage liver disease
Causes of small bowel obstruction in children vs adults
children:
- intussuscpetion
- malrotation
- hernias
.
adults:
- adhesions
- hernias
- crohn’s strictures
Causes of large bowel obstructions in children vs adults
children:
- Hirschsprung’s disease
.
adults:
- colon cancer
- diverticulitis
- volvulus
What is Hirschprung’s disease
- congential disorder of colon where there is a lack of myenteric + submucosal plexuses
- parasympathetic neuroblasts fail to migrate from neural crest to distal colon > developmental failure of meissner + Auerbach plexuses
- causing hypomobility + constipation
