GI Emergencies Flashcards
What is peritonitis?
Inflammation of the serosal membrane that lines the abdominal cavity
How does peritonitis occur if the peritoneal cavity is normally a sterile environment?
Primary: Spotaneous inflammation
Secondary: Breakdown of peritoneal membranes leading to foreign substances entering the cavity
What is spontaneous bacterial peritonitis? How do you diagnose it
Primary peritonitis often seen in patients with end stage liver disease → an infection of ascitic fluid that cannot be attributed to any intra-abdominal ongoing inflammation
Diagnosed by aspirating ascitic fluid, neutrophil count >250 cells/mm3
Explain how end stage liver disease leads to ascites
Cirrhotic liver has 2 main effects:
- Portal hypertension increases hydrostatic pressure in the capillary
- Decreased albumin production decreases oncotic pressure in the capillary
- Results in a net movement of fluid into the peritoneal cavity
What symptoms are associated with spontaneous bacterial periotnitis?
- Abdominal pain
- Fever
- vomiting
- Often mild
What are some of the common causes of secondary bacterial perionitis?
- Peptic ulcer disease (perforated)
- Appendicities (perforated)
- Diverticulitis (perforated)
- Post surgical (especially laproscopic)
What are some of the non-bacterial causes of secondary peritonitis?
- Tubal pregnancy (ectopic rupturing into peritoneal cavity → blood is highly irritant)
- Ovarian cysts
How does peritonitis present clinically?
-
Pain most common symptom
- may be gradual or acute
- diffuse if perforated into viscera
- Patients often lie very still wth shallow breathing and flexed knees to avoid making to pain worse
How would you treat peritonitis?
- Control the infectious source → surgery
- Eliminate bacteria and toxins → antibiotics
- Maintain organ system function → may admit to ICU
What are some of the common causes of bowel obstrucion in adults vs children?
Children:
- Intussusception
- Intestinal atresia
Adults:
- Adhesions
- Incarcerated hernias
What is intussusception?
When one part of the gut tube telescopes into an adjacent section
How would you treat bowel intusssusception?
- Air enema (pump air into recutm)
- Surgery if enema unsuccessful
In an intussusception, at what point would you get oedema?
As soon as the lymphatic and venous drainage is impaired
What are some of the symptoms of intussusception?
- Abdominal pain
- Vomiting
- Haemoatochezia
Where does Meckel’s diverticulum most commonly occur?
Located in the distal ileum, 2ft away from the ileocaecal valve
What are the common symptoms of small bowel obstruction?
- Nausea and vomiting (most common, present early)
- Abdominal distension
- Absolute constipation comes later
What are some of the causes of small bowel obstruction?
-
Intra-abdominal adhesions
- arise after >50% of abdominal surgeries
- Damage to mesothelium
- capillary bleeding leads to fibrongen exudate
- Hernias can narrow lumen enough to cause obstruction
-
Inflammatory bowel disease
- repeated episodes of inflammation/ healin in Crohn’s
How would you diagnose small bowel obstruction?
- History of abdominal pain, crampy, in cyclical periods (due to perilstalsis)
- Physical examination: distended abdomen, increased/absent bowel sounds, +/- hernia
- Imaging
What are some of the common causes of large bowel obstruction?
- Colon cancer (60%)
- Diverticular disease (20%) repeated inflammation → narrowing
- Volvulus (5%) of sigmoid or caecum
What are some of the symptoms of large bowel obstruction?
- Change in bowel habit (cancer)
- Abdominal distension
- Crampy abdominal pain
- Nausea and vomiting comes later if ileocaecal valve incompetent and allows backflow
- Typically gradual unless volvulus which is acute onset
What is volvulus?
Where part of the colon twists on its mesentry, resulting in bowel obstruction, can result in infarct
How can a high fibre diet predispose someone to volvulus?
High fibre diets cause bulkier stools adding weight into the large intestine which can cause it to twist on its axis
How does age change whether the bowel obstruction is more likely to be large or small?
Small bowel more commonly obstructed in younger age group
Large bowel more common obstructed in older age group
How do you differentiate between the small and large bowel on Xray?
Small bowel:
- smaller distensions
- central
- plicae circularis
Large bowel:
- around the periphery
- largery distension
- haustra
What is acute mesenteric ischaemia and what are some of the causes?
Symptomatic reduction in blood supply to the GI tract
More common Females (75%) and if there is a history of peripheral vascular disease
- Acute occlusion (70%) - arterial embolism of SMA
- Non occlusive ischaemia - low cardiac output
- Mesenteric venous thrombosis
Which area is particularly vulnerable to acute mesenteric ischaemia?
The splenic flecture as it has the least colateral blood supply (watershed area)
What clinical findings would indicate acute mesenteric ischaemia?
- Abdominal pain that is disproportionate to the clinical findings
- classically comes on 30 mins after eating and lasts 4 hours
- Nausea and vomiting
- Pain often left sided as splenic flexure is fragile
How would you treat acute mesenteric ischeamia?
- Surgery - resection of ischaemic bowel
- Thrombolysis/ angioplasty (if caught at early stages)
- Mortality is high
Which artery is vulnerable to erosion by a peptic ulcer in the 1st part of the duodenum?
Gastroduodenal artery
Where does blood from oesphageal varices drain to?
Portal drainage: oesophageal veins drain into the left gastric vein and into the portal vein
Systemic drainage: oesophageal veins drain to azygous system, drains into superior vena cava
How would you treat oesophageal varices?
- Band Ligation
- If not controlled by band ligation insert a TIPS (transjugular inrahepatic portosystemic shunt)
- expandable metal placed in teh liver to bridge the portal vein and hepatic vein which decompresses portal vein pressure
What is an abdominal aortic aneurysm? How does it typically arise?
A permanent pathological dilation of the aorta with a diameter >1.5 times the expected AP diameter of that segment
Typically due to the degeneration of the elastin and collagen of the media layer of the arterial wall
Give some risk factors for developing an AAA
- Male
- Inherited risk
- Increasing age
- Smoking
In which location do most AAAs occur?
Infrarenal (90%)
What are the symtpoms of AAA?
Usually asymptomatic until acute expansion or rupture
Can cause symptoms by compressing nearby structures:
- nausea, urinary frequency and backpain
Usual presentation when ruptured:
- abdominal pain +/- flank/ groin pain
- back pain
- pulsatile abdominal mass
- transient hypotension → syncope
- sudden cardiovascular collapse
How can you diagnose AAA?
- Physical examination
- Ultrasonography (pouch of morrison good place)
- CT
- Plain x-ray (if aneurysm is calcified)
How would you treat AAA?
- Non surgical: smoking cessation, hypertension control
- Surveillance monitor for size
- Surgery
- Endovascualr repair - reline the aorta using an endograft → inserted through the femoral artery
- Open surgical repair - add synthetic graft
