Ischemic colitis: Clinical sciences

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Introduction0:00–0:52

Ischemic colitis, or IC for short, is the most common form of intestinal ischemia. It is typically caused by reduced intestinal blood flow, usually due to small vessel occlusion or hypoperfusion of the colon.
Hypoperfusion usually follows the blood supply pattern and is most common in the watershed areas, so the splenic flexure and rectosigmoid junction.
This occurs because the arteries supplying the watershed areas are the most distal branches, so when blood flow to the intestine decreases, they’re the most likely to suffer from insufficient blood supply.
Reduced intestinal perfusion causes injury to the colon mucosa. However, prolonged hypoperfusion can result in transmural ischemia, which can further lead to complications, such as fulminant gangrene, perforation, and peritonitis.

Unstable patient0:52–2:45

Now, when assessing a patient with suspected IC, start with an ABCDE assessment to determine if your patient is unstable or stable.
If the patient is unstable, you should prioritize acute management to stabilize their airway, breathing, and circulation.
This means that you might need to intubate the patient, establish IV access, or administer fluids before continuing with your assessment.Once the patient is stable, determine the cause of their instability, and proceed with a focused history and physical examination.
History usually reveals severe abdominal pain, tenesmus, and bloody diarrhea; while a physical exam might reveal signs of shock, such as hypotension and tachycardia.
Sometimes, you may also find signs of peritonitis, like rebound pain, rigidity, or guarding.If you see these signs, start supportive care, which means continuing IV fluids, and administering empiric, broad-spectrum antibiotics.
But, here’s the thing. These findings are not specific to ischemic colitis only, so you should order abdominal imaging such as X-ray or CT to look for bowel dilation and signs of complications such as perforation or peritonitis.
Important findings to look for include pneumatosis coli, or the presence of gas within the bowel wall; as well as portal gas, which refers to gas in the portal vein or its branches; and pneumoperitoneum, or free gas in the peritoneal cavity.
In this case, call the surgical team for emergent consultation and laparotomy. Alright, let’s go back all the way to the ABCDE assessment and take a look at how to approach a stable individual with suspected ischemic colitis.

Stable patient2:45–4:15

Start by obtaining a focused history and physical examination, as well as labs, such as CBC and lactate. Now, history typically reveals crampy abdominal pain that developed rapidly, usually in the left lower quadrant; as well as tenesmus.
Additionally, the patient might report mild rectal bleeding or bloody diarrhea, which usually develops within 24 hours of the abdominal pain.
Here’s a high-yield fact! When taking history, be on the lookout for risk factors for colonic ischemia.
First, there are factors like hypertension or diabetes melitus that damage small blood vessels and decrease blood flow to the colon.
Another risk factor is atrial fibrillation, which can lead to thromboembolic complications involving the small vessels like those of the colon.
Finally, an important risk factor is aortic surgery, during which the aorta and its branches might be temporarily clamped, which can cause hypoperfusion of the colon.Let’s move on to the physical exam.
On palpation, patients with IC will usually present with tenderness and mild distension. Sometimes, there is also guarding.
Finally, labs might reveal elevated white blood cells and lactate. Okay, if you suspect IC based on history, physical examination, and labs, you should proceed with supportive management.
This includes fluid resuscitation, bowel rest, hemodynamic monitoring, and administration of empiric broad-spectrum antibiotics.Once you start supportive care, order a CT scan with IV and oral contrast.

Supportive management4:15–4:36

Be on the lookout for any signs of end stage bowel ischemia and necrosis, which will show up as pneumatosis coli, which can lead to air in the mesenteric vessels; as well as air in the portal venous system; or signs of perforation like free air in the abdomen.

Imaging4:36–5:54

If you see any of these, call the surgical team for consultation and emergent laparotomy. On the other hand, If you didn’t see any signs of necrosis on CT, you can’t rule out IC just yet.
IC without necrosis usually presents with bowel wall thickening and submucosal edema, which appears as “thumbprinting” on radiograph or CT imaging.
Additional CT findings include a target sign caused by the hyperemic mucosal and serosal layer of the colon wall, which appear hyperdense on CT; and the edematous submucosal layer, which appears hypodense on CT with or without associated pericolonic stranding.
These findings are usually found in the watershed areas. Finally, sometimes there might not be any CT findings that suggest ischemic colitis.Alright, now that we covered all the signs of ischemic colitis on imaging, let’s move on to the colonoscopy.
In patients who don’t have signs of necrosis on CT, you should order a colonoscopy with biopsies to confirm the diagnosis of ischemic colitis and rule out other causes of colon inflammation, such as inflammatory bowel disease or pseudomembranous colitis.

Colonoscopy5:54–6:52

Signs of IC on colonoscopy include fragile mucosa, segmental erythema, erosions, and petechial hemorrhage with pale mucosa in between.
The biopsy is usually not specific to ischemic colitis, but it helps rule out other conditions. So, if you see any of these signs, you can confirm the diagnosis of IC.
On the flip side, if there are no findings suggestive of ischemic colitis on colonoscopy with biopsy, or results point to something else, you should consider an alternative diagnosis.
Now that we’ve diagnosed IC, let’s move on to treatment. Treatment for IC usually involves continuing supportive care, which may include avoiding hypotension or giving high dose vasopressors, as well as observing them until their CBC and lactate go back to normal.

Treatment6:52–7:27

Usually, patients improve after 2 to 3 days. However, if they don’t improve, or even develop signs of worsening or complicated disease, you should call the surgical team for emergent consultation and possible laparotomy.
Alright, as a quick recap… Patients with ischemic colitis can present as unstable or stable. If the patient is unstable, stabilize them and perform an abdominal X-ray or CT to look for signs of complications, such as colon dilation, pneumatosis, portal gas, and pneumoperitoneum.

Review7:27–8:39

Patients with complicated ischemic colitis require emergent surgical consultation and laparotomy. On the other hand, stable patients require supportive care with fluid resuscitation, bowel rest, and broad-spectrum antibiotics.
Next, they should be assessed using CT with IV and PO contrast. CT usually shows signs of colon inflammation like thickening and edema of bowel walls, thumbprinting, or a target sign.
Then, patients with these signs should be further evaluated using colonoscopy with biopsies. Colonoscopy findings typically include fragile mucosa, erythema, erosions, and petechial bleeding with pale mucosa in between.
When it comes to treatment, IC is usually treated with supportive care. If the patient doesn’t improve in 2 to 3 days or worsens, the surgical team should be called for an emergent laparotomy.
and petechial bleeding with pale mucosa in between when it comes to treatment I see is usually treated with supportive care If the patient doesn't improve in 2 to 3 days or worsens The