Small Intestine Bleeding

Definition of small intestine bleeding

The small intestine (small bowel) is a long, narrow pathway in the digestive tract. It is described as ‘small’ because its opening (also known as the lumen) is approximately 2.5 centimetres smaller than the large intestine’s opening.

Small intestine bleeding refers to the loss of blood from abnormalities in the lining of the jejunum and the ileum (parts of the small intestine). Small intestine bleeds account for 5-10% of all GI bleeds. It is the least common type of GI bleeding. Bleeding within this area may require multiple blood transfusions, hospitalisations, and diagnostic procedures (e.g., X-rays). 

Importance of understanding the condition 

Due to the low prevalence of small bowel bleeding, this condition can often be misunderstood. However, this condition may be classed as a medical emergency. Therefore, small intestinal bleeding can require immediate intervention to reduce the risk of further complications. 

Many individuals diagnosed with this condition often have multiple comorbidities.¹ This may influence the risk for mortality, even when modern, effective therapeutic procedures are undertaken. It is important to understand the condition and how other factors may interact with the development and management of small intestinal bleeding. 

Causes of small intestine bleeding

A variety of lesions may result in small intestine bleeding. These lesions may occur in:²

• Elderly individuals (>65 years). Bleeding is often a result of vascular abnormalities and small intestinal ulcers. 
• Middle-aged adults (41-64 years). In this age group, the same causes for small intestinal bleeding as elderly adults are reported. 
• Young adults (<40 years). The most common cause of small bowel bleeding in young adults is caused by a type of inflammatory bowel disease known as Crohn’s disease, followed by small intestinal tumours and non-specific enteritis. 

Common sources of small intestine bleeding

The most common causes of small intestinal bleeding include:

• Angiodysplasia is responsible for 6% of lower GI bleeding cases. It is a common cause of small intestinal bleeding within the elderly population. Andiodysplasia describes the formation of arteriovenous malformations between previously healthy blood vessels. Some conditions are associated with increased frequency of GI angiodysplasia, including chronic renal failure and aortic stenosis^3,4
• Telangiectasias is slightly different to angiodysplasia because of its association with cutaneous and mucous membranes. Whereas angiodysplasia only involves the GI tract mucosa. This cause of small intestinal bleeding is often present within a younger age group due to its hereditary nature. 
• Gastrointestinal stromal tumours (GIST) occur in 30-35% of small intestinal bleeding cases.⁵ GI bleeding is usually caused by compression, ischaemia, or infiltration from the tumours. 
• Small bowel ulcers may be caused by non-steroidal anti-inflammatory drugs (NSAIDs), intestinal tuberculosis, Crohn's disease, tumours, medications, and coeliac disease
• Meckel’s diverticulum (MD) most common presentation within adults is small intestinal bleeding. MD is a congenital abnormality of the small bowel, and many with this condition remain asymptomatic their entire life

Other causes

Less common causes are:

• Dieulafoy's Lesion is a rare cause of small intestinal bleeding. This is because, most commonly, dieulafoy’s lesion is present within the stomach and not the small bowel. However, dieulafoy’s lesion may cause life-threatening small intestinal bleeding
• Small bowel varices are dilated veins occurring in the small intestine. Enlargement of veins in this area is often associated with high blood pressure within the blood vessels (portal hypertension) or abdominal surgery. Varices are uncommon causes of small intestinal bleeding⁶
• Jejuno-ileal diverticula usually produces bleeding that is massive and recurrent in nature
• Haemobilia refers to the abnormal communication between the vessels and the biliary system. It may be difficult to diagnose. However, it should be investigated within individuals who have a prior history of blunt trauma of the abdomen or medical procedures within this area

There are also various other causes of small intestinal bleeding, including endometriosis, radiation enteritis, aortoenteric fistula, and intestinal infestation by worms. 

Symptoms and diagnosis of small intestine bleeding

Common symptoms

Bleeding from the small bowel may be occult or overt. 

• When the bleeding is occult, it means that the bleeding is not visible. It may cause anaemia (a low blood count). Anaemia may cause symptoms such as tiredness, shortness of breath, and heart palpitations. However, you may have anaemia and have no symptoms
• When the bleeding is overt, it means that the bleeding is visible. If you have overt small intestinal bleeding, you may notice blood when you have a bowel movement (also known as rectal bleeding), or your faeces may be black and tarry

If your bleeding occurs suddenly and progresses rapidly, you may go into shock. Shock is a medical emergency, and you should seek immediate medical intervention. Symptoms of shock may include:

• Drop in blood pressure
• Not urinating, or urinating frequently, in small amounts
• Rapid pulse
• Loss of consciousness

Diagnostic tools used to identify the cause of bleeding

A variety of endoscopic and radiological tests may be used to look at the small bowel for bleeding. These may include:²

• Endoscopy - Endoscopy is a test to look inside your body. It uses a long, thin tube with a small camera attached. This is passed into your body, usually through a natural opening (e.g., your mouth). A regular endoscopy will look at the oesophagus, stomach, and duodenum (the first part of the small intestine). Whereas capsule endoscopy is one type of endoscopy that is often superior to other diagnostic tests for diagnosing small intestinal bleeding because it looks further down the small intestine. It is often the first test of choice if your doctor suspects small intestinal bleeding. You will swallow a capsule that has a camera attached, and as it moves through your digestive tract, it can take photographs for your doctor to examine
• Multiphase CT scan - This type of scan has a higher sensitivity than capsule endoscopy for the detection of small bowel tumours. This test uses X-rays and an intravenous contrast agent to capture images of different anatomical parts of the body at different times. A major limitation of this type of test is that it cannot perform therapeutic procedures for small intestinal bleeding
• Angiography - This procedure can be used as a diagnostic procedure and a therapeutic management intervention. The diagnostic efficacy of this test has been reported at 61-77% for those with overt bleeding, compared to <20% for those with inactive or suspected occult bleeding.⁷ There are complications of this procedure, including renal impairment, bowel infarction, infections, and bleeding at the catheter site
• Push enteroscopy (PE) is often used when lesions and bleeding are further down in the small intestine and cannot be reached by regular endoscopic procedures. It utilises 2 balloons that help it go further down the small intestine

Treatment of small intestine bleeding

Oftentimes, tests (e.g., endoscopy) used for diagnostic reasons can also be useful for the therapeutic management of small bowel bleeding. 

If you have acute overt bleeding, oftentimes, resuscitation localisation of bleeding, followed by endoscopic intervention and therapeutic procedures, will be required. Whereas, if you have occult or intermittent overt bleeding, these steps may be followed in combination with the conservative measure of iron supplementation. 

Conservative measures

As previously mentioned, the most common type of conservative measure for the management of small intestinal bleeding is iron supplementation. This management is only used when the bleeding is occult (or intermittently overt). Iron supplementation is often taken orally or intravenously, and it would be expected that 10-20 milligrams of oral iron can be absorbed per day. 

Endoscopic interventions

An enteroscopy is a type of endoscopic procedure. During an enteroscopy, a doctor inserts a thin tube with a camera and one or two balloons into the body, either through the mouth or the anus. Different types of enteroscopy may be utilised for the diagnosis and treatment of small intestine bleeding:²

• Deep enteroscopy (DE) - The role of DE is to treat small bowel lesions detected via screening processes. The procedure can be relatively invasive and will require the administration of anaesthetic. Complications of DE may include ileus perforation, cardiopulmonary complications, bleeding, and pancreatitis
• Push enteroscopy (PE) - helps to visualise the distal duodenum and proximal jejunum of variable lengths, therefore reaching further into the small intestine than the standard upper GI endoscopy

Surgical interventions

• Laparoscopy or laparotomy may be considered in those whose small bowel bleeding is not amendable by endoscopic/radiological therapy or when it is required to cut out tissue or part of an organ, e.g., Meckel’s diverticulum or mass lesion⁸
• Intraoperative endoscopy - This type of procedure is used for those who have refractory bleeding and known small bowel lesions, and when endoscopic and radiological tests have not worked for the diagnosis and treatment of bleeding
• Catheter angiography or digital subtraction angiography (DSA) - An intra-arterial injection is given after a cannula is inserted into the visceral arteries. This procedure is useful as it can perform an embolisation of the bleeding vessels
• Occasionally, a combination of radiology and surgery may be successful in the management of small intestinal bleeding

Prognosis and prevention

You can reduce your risk of developing small intestinal bleeding by:

• Practising the safe use of NSAIDs. NSAIDs are often used for the treatment of headaches, stomachaches, arthritis, common colds and flu. Type of NSAIDs may include aspirin and ibuprofen. One study that examined the difference between NSAID users and those who do not use NSAIDs, showed a 7.8% increase in the occurrence of small intestinal ulcers.⁹ It is known that NSAIDs cause increased permeability within 12 hours and inflammation within the small intestine within 10 days.¹⁰ Therefore only taking NSAIDs when necessary can help reduce the risk of developing small intestinal bleeding
• Limiting alcohol use. Excessive consumption of alcohol is known to cause liver problems such as cirrhosis. But did you know increased alcohol use can also increase your risk for small bowel bleeding? There is a particularly increased risk for those who excessively consume alcohol alongside NSAIDs
• Quitting tobacco if you regularly use it. Regular tobacco use can increase your risk for bodily bleeding, including small intestinal bleeding.¹¹ Tobacco can increase the pH of your stomach acid and cause sores, resulting in bleeding
• Getting treatment to keep symptoms of GI conditions, like gastroesophageal reflux disease (GERD), well-managed
• Checking for infections like helicobacter pylori, if one is at risk, that can cause ulcers. Helicobacter pylori can often enter your digestive tract via your mouth. It is a fairly common bacteria, 44% of the world’s population carries this bacteria. It is most common in developing countries that may not have fresh, running water. However, it is important to consult your doctor if you believe you are at risk for helicobacter pylori infection

There are limited studies regarding the prognosis after a small bowel bleed. Most of the complications in hospitals  occur in patients with comorbid conditions. Death usually occurs due to the worsening of underlying comorbidities. Increasing age has been shown to increase mortality. The mortality rate was higher in men than women. The negative prognostic factors involve hypovolemia, transfusion requirement, and underlying coagulopathies. Long-term follow-up studies are limited for small bowel bleeding.

Summary

Small intestinal bleeding refers to blood loss from the jejunum and ileum of the lower gastrointestinal tract. Bleeding within this area often occurs as a refractory response from small intestinal lesions and ulcers. Diagnosis of small intestinal bleeding may include a variety of tests and is often performed on the basis of exclusion of other problems and conditions. Diagnostic tests may include certain types of endoscopies, CT scans, and angiographic procedures. Symptoms of small intestinal bleeding may be categorised into occult and overt. Occult symptoms may include shortness of breath, heart palpitations, and tiredness, all associated with anaemia. Whereas overt symptoms include rectal bleeding and bloody faeces. If blood loss occurs quickly and progresses rapidly, there is a likelihood of going into shock. Shock is a medical emergency, and you can experience a rapid reduction in your blood pressure, a rapid pulse, and unconsciousness. Many diagnostic procedures may also be utilised for the therapeutic management of small intestinal bleeding including. However, sometimes, other management techniques will be required. You are able to reduce your risk of developing small intestine bleeding by reducing your use of NSAIDs, alcohol and tobacco and receiving relevant treatment for other gastrointestinal issues. It is important to understand that small bowel bleeding can be classed as a medical emergency, and fatality is a prognosis when quick, efficient treatment is not sought. However, for the majority of individuals, small intestinal bleeding can be treated before major complications.