Gi Emergencies Flashcards
What is SBP
Most commonly seen in patients with end stage liver disease (patients with cirrhosis) Spontaneous bacterial peritonitis (SBP) is an infection of ascitic fluid that cannot be attributed to any intra-abdominal, ongoing inflammatory, or surgically correctable condition
• Ascites is a pathological collection of fluid within the peritoneal cavity •In cirrhosis it is caused by a combination of:
• Portal hypertension- Causing increased hydrostatic pressure in the veins draining the gut
• Decreased liver function resulting in less albumin production- Decreased intravascular oncotic pressure
• The result is the net movement of fluid into the peritoneal cavity
- Symptoms of abdominal pain, fever, vomiting
- Commonly symptoms are mild
- Diagnosed by aspirating ascitic fluid- neutrophil count >250 cells/mm³
What is secondary peritonitis
Secondary (surgical) peritonitis is a result of an inflammatory process in the peritoneal cavity secondary to inflammation, perforation, or gangrene of an intra-abdominal or retroperitoneal structure
• Remember the peritoneal cavity is normally a sterile environment
•If a viscera perforates then the contents will enter the peritoneal cavity
•Common causes of secondary bacterial peritonitis include:
• Peptic ulcer disease (perforated)
• Appendicitis (perforated)
• Diverticulitis (perforated)
• Post surgery
- Non bacterial causes
- Tubal pregnancy that bleeds (the peritoneal cavity is not enclosed in females)
- Ovarian cyst
- Blood is highly irritant to the peritoneal cavity
What are teh symptoms of peritonitis
Abdominal pain is the most common symptom
• This may come on gradually or acutely
•Diffuse abdominal pain is common in perforated viscera
•Patients often lie very still as any movement makes the pain worse
• Often have knees flexed
• Shallow breathing
•Treatment approaches
Wha are the treatment approaches for peritonitis
Treatment approaches •Control the infectious source • Surgery •Eliminate bacteria and toxins • Antibacterial therapy •Maintain organ system function • Intensive care
What is bowel obstruction and wat are common causes
Bowel obstruction is a mechanical or functional problem that inhibits the normal movement of gut contents
• This can affect the large and small intestine
•All ages can be affected
- Common causes in children include:
- Intussusception • Intestinal atresia
- Common causes in adults include:
- Adhesions • Incarcerated hernias
What is intussusception and what is thr treatment
Intussusception is when one part of the gut tube telescopes into an adjacent section
• The cause is not well known
• Potential motility issues
• ‘Lead point’ (a mass that precipitates the telescoping action)
- Meckel’s diverticulum
- Enlarged lymph node
•The intussusception can extend quite far (even prolapse out of rectum)
•As soon as the lymphatic and venous drainage is impaired you get oedema
• Enough oedema can impede arterial supply (infarction)
•Classically you get abdominal pain, vomiting and haematochezia
•Treatment
• Air enema
• Surgery
What are the Cuba’s of small bowel obstction
Nausea and vomiting (bilious) are most common symptom (early) • Abdominal distension •Absolute constipation (late) •Caused by:
• Intra-abdominal adhesions (abnormal fibrous bands between organs or tissues or both in the abdominal cavity that are normally separated)
• Arise after more than 50% of abdominal surgeries
• Greater omentum involved in 80%, bowel in 50% • Damage to mesothelium (direct trauma, post operative infection)
• Capillary bleeding leads to exudation of fibrinogen • Other consequences of adhesions
• Abdominal pain, secondary infertility
How can hernias cause small bowell obstructing
- Hernias can narrow lumen enough to cause obstruction
- Incarcerated groin hernias most common
- Inflammatory bowel disease
- Crohn’s
- Repeated episodes of inflammation/healing causes narrowing
Descrbe the small bowell obstruction diagnosis
Diagnosis
• History- abdominal pain is crampy, intermittent
• Physical examination- abdominal distension, increased/absent bowel sounds, presence of hernia
• Imaging-
Wha are common causes and symptoms of large bowel obstruction
Typically affects older generation • Common causes include: • Colon cancer (60% of mechanical obstructions) • Diverticular disease (20%) • Volvulus- Sigmoid, Caecal (5%)
- Symptoms often appear gradually if caused by cancer but are abrupt with volvulus
- Change in bowel habit (cancer)
- Abdominal distension
- Crampy abdominal pain
- Nausea/vomiting (later)
What is volvulus
Derived from Latin ‘to twist’
• Part of the colon twists around its mesentery
•Most common in sigmoid colon (60%) and caecum (but can technically occur anywhere)
•Results in obstruction
•Can result from overloaded sigmoid colon (constipation)
- Extra mass predisposes elongates the sigmoid (relatively smaller mesenteric attachment)
- High fibre diets can also lead to sigmoid overload and twisting
•Caecal volvulus results in small and large bowel obstruction
Omapre small vs large bowel obstruction
Ss
Compare small and large bowel obstruction imaging
Ss
What is acute mesenteric ischaemia
Symptomatic reduction in blood supply to the GI tract
• More common in females (75%) and if you have a history of peripheral vascular disease
•Acute occlusion (70% of cases)
- Arterial embolism in SMA (50%)
•Non occlusive mesenteric ischaemia (20%)
- Low cardiac output
•Mesenteric venous thrombosis (5-10%)
- Systemic coagulopathy, malignancy
Describe teh diagnosis and investigations of acute mesenteric ischaemia
Most cases are in more elderly patients with a cardiovascular risk factors
• Can be difficult to diagnose because the symptoms can be fairly non-specific
•Abdominal pain (if present) is disproportionate to the clinical findings
- Classically pain comes on 30 minutes after eating (and last 4 hours)
•Nausea and vomiting are often present
•Pain can often left sided because the blood supply to the splenic flexure is most fragile
- Investigations
- Blood tests
- Metabolic acidosis/increased lactate levels
- Erect chest x-ray (to check for perforation)
- CT angiography is used (sensitivity is >90%) –intravenous contrast
What are the treatments for acute mesenteric ischaemia
Treatment • Surgery- resection of ischaemic bowel
• bypass graft •Thrombolysis/angioplasty
•Mortality is high (arterial thrombosis up to 70% mortality)
• Often older patients with comorbidities
Describe oesophageal varices
Oesophageal varices
• This is an example of a porto-systemic anastomosis
• 12-14% of acute upper GI bleeding
• In case of oesophageal varices
• Portal drainage- Oesophageal veins drain into left gastric vein, drains into portal vein
• Systemic drainage- Oesophageal veins drain into azygous vein, drains into superior vena cava
What is band ligation
-
What are treatments of oesophageal varices
If bleeding is not controlled by the ‘banding’
• TIPS (Transjugular intrahepatic portosystemic shunt)
- An expandable metal is placed within the liver
- Bridges the portal vein to an hepatic vein
• Decompresses the portal vein pressure
• Reduction in variceal pressure
• Reduction in ascites
- Drug treatment
- Terlipressin
- Reduces portal venous pressure
What are AAAs
Abdominal aortic aneurysm (AAA) is a permanent pathological dilation of the aorta with a diameter >1.5 times the expected anteroposterior (AP) diameter of that segment, given the patient’s sex and body size. The most commonly adopted threshold is a diameter of 3 cm or more. More than 90% of aneurysms originate below the renal arteries
Usually due to the degeneration of the media layer of the arterial wall
• Media- smooth muscle cells with elastin & collagen
- AAAs form due to degradation of elastin and collagen
• Lumen gradually starts to dilate
Most AAAs are infrarenal (>90%)
Risk factors • Male • Inherited risk • Increasing age • Smoking
Whar are the symptoms of aaa
Normally asymptomatic until acute expansion or rupture
• Can cause symptoms by compressing other nearby structures
• Stomach, bladder, vertebra
- Nausea, urinary frequency and back pain
•Usual presentation of rupture
• Abdominal pain (+/-flank and groin pain)
• Back pain
• Pulsatile abdominal mass
• Transient hypotension
- Syncope
- Retroperitoneum can temporarily tamponade the bleed
• Sudden cardiovascular collapse (65% of ruptured AAAs die before hospital)
Desrube the diagnosis of aaa
Physical examination
• Presence of a pulsatile abdominal mass (less than 50% of cases)
Ultrasonography
• Non invasive and in the right hands very sensitive and specific
• Can also detect free peritoneal blood
Computed Tomography (CT)
• Can detect a lot of surrounding anatomy that may be relevant
• Planning for elective surgery
Plain x-rays
• If aneurysm has calcified then can be seen on plain x-rays
What are non surgical treatment of aaa
Non surgical
• Smoking cessation
• Hypertension control
•Surveillance of AAA
• Less than 5.5cm (most grew slowly enough to not need treatment)
• More than 5.5 cm- refer to vascular surgeons
What are surgical treatment of aaa
Surgery •Endovascular repair- relining the aorta using an endograft (an exoskeleton of metallic stents over a fabric lining)
• Inserted through the femoral artery (seals below renal arteries and above common iliacs)
Open surgical repair
• Clamp aorta
•Open the aneurysm (remove thrombus and debris)
•Suture in a synthetic graft to replace diseased segment
