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Acute Abdomen - Mesenteric Ischaemia - Coggle Diagram
Acute Abdomen - Mesenteric Ischaemia
Definition
Epidemiology
8% of ED presentation
Differential
Abdominal aortic aneurysm
Perforation
Obstruction
Mesenteric ischaemia
Ectopic pregnancy
Torsion
Pain
Visceral Pain
Parietal Pain
Segmental innervation - parietal peritoneal inflammation causes pain to overlying skin
Referred Pain
Occurs when visceral afferent fibres synapse at the same level as s??? but different to visceral pain
Chronology of Pain
A Subside spontaneously with time
B Colicky - pain progresses and remits over time
C Abdominal pain is progressive
D Catastrophic
History
Exacerbating and relieving factors give good insight into cause
Peritonitis worsened by moving
Renal colic causes writhing
Gastric ulcers worse with food
Duodenal ulcers better with food
Biliary colic worse with fatty food
Physical Examination
Inspe
Investigations
Bedside
Mesenteric Ischaemia
Definition
Insufficient splanchic blood flow to meet metabolic demands of the viscera
Types
Chronic
Acute
Strangulated obstruction
Non-occlusive
Venous occlusive
Arterial occlusive
Thrombotic
Embolic
Causes
Occlusion
Thrombosis
Relative hypovolaemia
Vasospasm (rare)
Prognosis
Depends of adequacy of collaterals and Duration of insult
Early diagnosis and tx imperative as consequences can be catastrophic
Anatomy - Blood Suply
3 Major Aortic Branches
Coeliac trunk
Branches
Supply
Foregut
Stomach
Spleen - technially mesoderm
Liver
Pancreas
Duodenum first 2 parts
Collaterals
With SMA via pancreaticoduodenal branches
Superior mesenteric artery
Supply
Midgut
3rd 4th Duodenum
Jejunum
Ileam
Caecum
Ascending colon
Proximal 2/3 transvese colon
Collaterals
With IMA and Coeliac
Inferior mesenteric artery
15-20% of cardiac output goes here - 35% when postprandial
Watershed Areas ⭐
Areas supplies by terminal branches of two large arterial
Prone to ischaemia - ischaemic colitis and non-occlusive mesenteric ischaemic
Griffith's point
Splenic flexure
Sudek's Point
Rectosigmoid junction
Chronic Mesenteric Ischaemia
Abdominal or Intestinal Angina
Definition
Narrowing of mesenteric vessels from atherosclerosis - inability of blood supply to hadle post-prandial demands
Classic Triad
Central colick post prandial pain
Weight loss
Abdominal bruit
Epidemiology
High risk of developing AMI (acute mesenterich ischaemia)
High risk of all -cause mortality at 5 year
Typically a asing of widespread peripheral vascular disease
Risk Factors
FHx
Age
Diabetes
Hypertension
High cholesterol
Smoking
Investigations
CT angiography to delineate narrowing
Management
Lifestyle
Smoking cessation
Optimise glycaemic control
Secondary Prevention
Statin
Antiplatelets
Revascularisation
1.Endovascular
Open - endarterectomy / bypass / remiplantation
Acue Mesenteric Ischaemia (AMI)
Definition
Catastrophic abdominal emergency characterised by sudden crital interruption to intestinal blood flow leading to infarction and possible death
Epidemiology
Uncommon - 1 in 1000 surgical admission
Significant morbidity and high mortality 50-80% especially in infarction
Every 6 hr delay doubles mortability
More common in elderly - 10% of acute abd > 70 y/o
Prevalence 17.7% in emergency laparotomy (31% in elderly trauma lap)
Aetiology
Non occlusive 20%
Venous occlusion <10%
Arterial Occlusive
Thrombotic 25%
Embolic
AMI Embolic
Epi
Most Common
Vessels
SMA most commonly affected due to sharp angulation from aorta and large calibre
Embolisms
Typically from left atrium
Septic embolic
Ruptured aortic plaque
Post MI mural thrombus
Prognosis
Sudden acute occlusion with no increased collaterls - worse ischaemia than thrombosis but better prognosis
AMI Thrombotic
Vessels
Commonl involves aortic ostia of the vessel - widespread infarction
Widespread atherosclerosis CAD, CVA, PAD
Presentation
Hx chronic ischaemia
Abdominal angina
Sitophobia
Weight loss
Causes
Thrombosis on top of atherosclerosis
Aortic Aneurysm
Non-Occlusive Mesenteric Ischaemia NOMI
Risk Factors
VEnous Occlusive Acute Mesenteric Ischaia
Causes
Definition
Risk Factors
Pathophysiology
Presentation
EArly
Late
Absoloute Ischaemia
Diagnosis
Managment
Resus
Lab Investigations
Imaging
CT
Angiography
Former gold Stand
Medical Treamtnet
Papaverine
Heparin
IR and Endovascular options
No signs of peritonitis
Surgical Intevention
Assessment of bowel viability
Clinical Judgment
Pink serosa
Visible peristalsis
Positive pulsation
Positive pulsation
Bleedin from cut edges
Doppler
Fluroscein
Does no replace clinical judgement - recieving blood could still be dead tissue
Injection of fluroscein and Woods lamp to assess perfusion
Resection of non-viable bowel
Specific intervention (embolectomy, bypass)
Surgical care
Stabilise and resuscitate as much as possible - lactate release may cause
Necrotic bowel
need
resection
May need seconda looc at 24-48hr - damage control surgery
CT Results