Transcript for GI bleeding
Gastrointestinal bleeding can be divided into upper and lower GI bleeding.
Upper GI bleeding arises above the ligament of Treitz- also called the suspensory ligament of the duodenum- and it includes bleeding from the esophagus, stomach, or duodenum.
Common causes of upper GI bleeding include peptic ulcer disease, erosive esophagitis, esophageal varices, an arteriovenous malformation or an AVM, Mallory-Weiss syndrome and cancers of the upper GI tract.
Lower GI bleeding arises below the ligament of Treitz and includes bleeding from the small intestines past the ligament of Treitz, large intestines, rectum, and anus.
Now, both upper and lower GI bleedings can be either visible or occult- meaning that there’s no visible evidence of bleeding. This is usually detected by a fecal occult blood test or if there are signs of iron deficiency anemia.
Okay, first things first. A visible upper GI bleed causes hematemesis- which is vomiting of blood, and suggests moderate to severe ongoing bleeding.
If the blood looks like coffee-grounds - it suggests that the blood has been oxidized by acid in the stomach so that the iron in the blood has turned black. It’s a sign that bleeding was a small quantity or has stopped.
Melena refers to black and tarry stools, and that most often result from upper GI bleeding. In fact, it takes about 50 milliliters of blood in the stomach to turn the stools black.
A lower GI bleeding can cause hematochezia- which is fresh blood passing through the anus which may or may not be mixed with stool.
In rare cases, if there’s a large upper GI bleed, that can cause hematochezia as well.
In an individual with a GI bleed, the first step is evaluating their hemodynamic stability.
In mild hypovolemia, less than 15% of the blood volume was lost, and it causes a resting tachycardia.
In moderate hypovolemia, 15% to 40% of the blood volume is lost, and it causes orthostatic hypotension- which is a decrease of over 20 mm Hg in the systolic blood pressure.
In severe hypovolemia, over 40% of the blood volume is lost, and it causes hypotension.
Active GI bleeding requires a prompt workup, and lab work includes a CBC which usually shows a normal hemoglobin level, because the individual is losing whole blood. Over the next 24 hours, there’s a physiologic compensation of holding onto more water, and intravenous fluids are usually given - and that decreases the hemoglobin level.
ALT, AST, GGT, bilirubin and albumin are done to assess liver function.
Coagulation studies including fibrinogen, a PT, PTT, and INR are done to rule out bleeding disorders.
Importantly, cross-matching for blood transfusions are also done.
In some situations, a nasogastric lavage can be done as well. That’s where a tube is placed down from the nose to the stomach to wash out the gastric contents. It’s usually done if an upper endoscopy will be done afterwards.
Now, with hemodynamically stable individuals, when an upper GI bleeding is suspected, an upper endoscopy is done within 24 hours and when lower GI bleeding is suspected, a colonoscopy is done within 24 hours to identify the source of bleeding.
With hemodynamically unstable individuals with signs of hypovolemia, two large caliber peripheral intravenous catheters - of at least 18 gauge or even larger-gauge are placed, and fluid resuscitation begins immediately with 500 milliliters of normal saline or lactated Ringer’s solution given over 30 minutes. Afterwards, the rate of fluid is adjusted depending on their hemodynamic status.
Next, intravenous proton pump inhibitors or PPIs like esomeprazole are given, initially as a bolus of 80 milligrams, followed by 40 milligrams twice daily, because they promote hemostasis and lower the risk of recurrent bleeding.
Blood transfusions may be done if the individual remains hemodynamically unstable.
Otherwise, in hemodynamically stable individuals, blood transfusions are done in older individuals with comorbidities for a hemoglobin below 9 grams per deciliter and in young and healthy individuals with a hemoglobin below 7 grams per deciliter.
Next, it’s important to do an upper endoscopy.
Now, in hemodynamically unstable individuals with a suspected upper GI bleeding, it’s important to have surgical and interventional radiology teams nearby, because an upper endoscopy can precipitate complications like perforation.
Alternatively, with a suspected lower GI bleeding, a nasogastric lavage or upper endoscopy is done to rule out upper GI bleeding, and then a colonoscopy is done afterwards.
Treatment depends on the specific cause of bleeding.
Treatment is done during the upper endoscopy and includes thermocoagulation therapy using cautery probes. Cautery probes use an electrical current to melt a tiny blood vessel and seal it shut to stop the bleeding. Another option is placing hemostatic clips on the blood vessel to stop the bleeding. Both of these methods can be combined with injecting epinephrine into the vicinity of the bleeding vessel which causes vasospasm and stops the bleeding.
Esophageal varices are diagnosed during an upper endoscopy and are dilated veins in the lower third of the esophagus.
Varices only appear in the lower third of the esophagus, because the superficial veins lining the mucosa drain into the left gastric vein which in turn drains into the portal vein.
Treatment consists of intravenous octreotide which is a somatostatin analogue that decreases portal blood flow. Antibiotic prophylaxis with IV ciprofloxacin is given for a week to lower the risk of a bacterial infection, and in severely-ill individuals, IV ceftriaxone is given instead.
An upper endoscopy is done within 12 hours of presentation and variceal ligation is done. That’s where small elastic bands are placed on the varices to stop them from bleeding. Another option is endoscopic sclerotherapy- meaning that a sclerosant solution like sodium morrhuate is injected in the varices endoscopically.
If there’s massive bleeding or if endoscopic therapy fails to stop the bleeding, then balloon tamponade is done using a Blakemore tube-which has two balloons- one balloon for the lower part of the esophagus and another balloon for the stomach, as well as a third lumen, through which gastric aspiration is done.
An individual needs to be intubated before inserting the Blakemore tube, to prevent pulmonary aspiration of gastric contents. The tube then is inserted through the nose and placed in the stomach before both esophageal and gastric balloons are inflated. This applies direct pressure which can stop an ongoing bleed. It can only be used for about 48 hours, because the pressure can further harm the esophagus and there’s often rebleeding once the balloons are deflated and removed.
When endoscopic approaches fail, another procedure is a transjugular intrahepatic portosystemic shunt or TIPS, which creates a path between the portal and systemic circulation in order to lower the portal pressure.To create this path, a needle catheter is inserted in the jugular vein and then a stent is placed between the hepatic vein and portal vein, linking the two circulations and bypassing the liver.
Mallory-Weiss syndrome happens due to forceful vomiting that leads to tears in the lower third of the esophagus and proximal stomach. This is usually associated with alcohol abuse.
On an upper endoscopy, a Mallory-Weiss tear looks like one or sometimes a few longitudinal breaks in the mucosa.
Treatment includes an antiemetic agent, like metoclopramide if there’s persistent vomiting. If there’s active bleeding, then endoscopic therapy with thermocoagulation, hemostatic clips placement or endoscopic band ligation is done.
A Dieulafoy lesion or exulceratio simplex Dieulafoy- is a more rare condition where there’s an unusually dilated arteriole that erodes the overlying mucosa and starts bleeding. It most often occurs in the stomach.
Treatment is usually a combination of epinephrine injection with thermocoagulation or hemostatic clips placement.
Another rare condition is Boerhaave syndrome, which is a rupture of the esophagus that’s caused by a sudden increase in intraesophageal pressure like from straining or vomiting. The spontaneous perforation usually involves the intrathoracic part of the esophagus. It leads to mediastinitis and mediastinal emphysema- which is basically a pocket of air surrounding the heart.
Symptoms begin minutes to hours after a perforation. Typically there’s severe retrosternal chest pain and on the physical examination, there’s crepitus on palpation of the chest wall due to subcutaneous emphysema. Later on, the individual can develop odynophagia, dyspnea and signs of sepsis.
A contrast esophagogram is done to establish the diagnosis- this uses gastrografin as contrast- because it’s water soluble and less irritating for the mediastinum. The extravasation of contrast material shows the location and extent of the perforation.
If the perforation is small, then it’s managed by avoiding oral intake for 7 days, giving parenteral nutrition support, and IV antibiotics like ticarcillin-clavulanate for 14 days, and drainage of any mediastinal fluid collections.
In large perforations, the treatment includes surgery to repair the perforation.
In extreme cases, an esophagectomy-which is the surgical removal of the esophagus- may be needed.
Moving on to causes of lower GI bleeding. Diverticulosis is the presence of diverticula which sometimes can bleed. A colonoscopy is performed within 24 hours of presentation.
Treatment is done during colonoscopy and includes thermocoagulation or injecting epinephrine in the vicinity of the bleeding. If the bleeding can’t be stopped endoscopically, then angiography can be used to identify the source of bleeding and vasoconstricting medication like vasopressin can be given. Alternatively, the bleeding vessel can be embolized.
If neither colonoscopy nor angiography are able to identify and stop the bleeding, then surgery is required and a segmental colectomy is done. That’s where part of the colon is removed.
Next, there’s colorectal cancer which is a serious cause of hematochezia, and it’s due to an ulcerated tumor.