Intestinal Ischaemia Flashcards
What is Ischaemic bowel disease?
Ischaemic bowel disease refers to a group of disorders where compromised blood flow to the intestines causes ischemia. It can affect the small intestine (mesenteric ischemia) or the large intestine (colonic ischemia) and ranges from mild, reversible injury to severe necrosis and infarction.
What are the types of Ischaemic bowel disease?
- Acute Mesenteric Ischemia (AMI): Rapid onset, often life-threatening, typically due to embolism, thrombosis, or non-occlusive ischemia.
- Chronic Mesenteric Ischemia (CMI): Gradual reduction in blood flow leading to ischemic symptoms with a high risk of acute events.
- Colonic Ischemia (CI): The most common form, primarily affecting elderly patients and involving the large bowel due to low blood flow in watershed areas.
What is the vascular anatomy related to Ischaemic bowel disease?
The intestines receive blood from the superior mesenteric artery (SMA), inferior mesenteric artery (IMA), and celiac artery, with anastomoses providing collateral flow. Watershed areas, like the splenic flexure and rectosigmoid junction, are particularly vulnerable to ischemia.
What are the mechanisms of ischemia in Ischaemic bowel disease?
- Arterial Embolism: Usually from the heart, causing sudden occlusion of the SMA.
- Arterial Thrombosis: Develops in patients with atherosclerosis; occurs gradually but can lead to acute events.
- Venous Thrombosis: Affects the mesenteric veins, leading to congestion and ischemia.
- Non-Occlusive Mesenteric Ischemia (NOMI): Caused by low-flow states, leading to decreased perfusion without physical obstruction.
What is the incidence and mortality of Acute Mesenteric Ischemia?
Incidence is low but has high mortality (50-80%) due to the rapid onset and difficulty in early diagnosis.
What are the symptoms of Acute Mesenteric Ischemia?
Sudden, severe abdominal pain out of proportion to physical findings, accompanied by nausea, vomiting, and sometimes bloody diarrhea as ischemia progresses.
What are the risk factors for Ischaemic bowel disease?
- Age: Higher risk in older adults due to atherosclerosis.
- Cardiovascular Conditions: Atrial fibrillation, myocardial infarction, and heart failure increase embolic risk.
- Smoking and Hyperlipidemia: Contribute to atherosclerosis.
- Medications: Vasopressors, digitalis, and diuretics may exacerbate NOMI.
- Surgery and Trauma: Abdominal surgeries and blunt trauma can lead to mesenteric injury.
What are the general examination findings in Ischaemic bowel disease?
Fever, tachycardia, and hypotension, especially in advanced ischemia or sepsis. Abdominal distension, vomiting, and signs of dehydration.
What imaging is used to diagnose Ischaemic bowel disease?
CT Abdomen with Contrast/CT Angiography is the primary imaging tool to detect ischemic changes such as bowel wall thickening, pneumatosis intestinalis, and mesenteric vessel occlusion.
What is the management for Ischaemic bowel disease?
- Conservative: Lifestyle modification, smoking cessation, dietary adjustments.
- Medical: Anticoagulation, vasodilators, antibiotics.
- Surgical: Revascularization (angioplasty, stenting), bowel resection if necrosis has occurred.
What are the complications of Ischaemic bowel disease?
- Short Bowel Syndrome: Following extensive bowel resection.
- Bowel Infarction and Perforation: Life-threatening and requires urgent surgical intervention.
- Sepsis and Septic Shock: Due to bacterial translocation through necrotic bowel.
- Strictures and Obstruction: Chronic ischemia can lead to scar tissue and strictures.
What is the prognosis for Acute Mesenteric Ischemia?
High mortality if not treated promptly, with better outcomes following revascularization.
What are the differentials of intestinal ischaemia?
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Acute Abdomen Causes: Appendicitis, diverticulitis, perforated peptic ulcer, which may present with similar symptoms.
- Chronic Abdominal Pain: Differential includes chronic pancreatitis and irritable bowel syndrome.
- Lower Gastrointestinal Bleed: Conditions like diverticulitis, inflammatory bowel disease, or malignancy should be considered if blood is present in stools
