What Is Melaena?

Melaena is one of the more striking signs in clinical medicine and can often be a sign of very significant conditions. As a result, patients may be particularly worried when they have melaena. But what is melaena? Melaena refers to a change in your stool where your stool appears black and tar-like with a very offensive smell. It is often a result of significant bleeding within the gastrointestinal tract. To find out more about Melaena, please continue reading.

Overview

Melaena refers to the appearance of dark, tarry stools which occurs as a result of bleeding in the gastrointestinal (GI) tract (your mouth, oesophagus, stomach, small and large intestines).^{1, 2} They are more associated with significant upper GI bleeding, which consists of your oesophagus, stomach or duodenum (the first part of your small intestine). This is different from lower GI bleeds, which occur in the rest of your small intestine and your large intestine and are more likely to result in rectal bleeding. Other symptoms of upper GI bleeding include coffee-ground vomit, where your vomit has a dark, coffee-like appearance. Gastrointestinal bleeding in particular upper gastrointestinal bleeding, can make patients very unwell and are often medical emergencies requiring prompt treatment.²

Causes of melaena

There are various causes of upper GI bleeding which can lead to melaena, and these include:^{2, 3}

• Perforated stomach or duodenal ulcers
• Liver disease as the liver disease causes engorged veins throughout the gastrointestinal tract called varies. These can occur in the oesophageal, and when they rupture, you get variceal bleeding
• Stomach cancer
• Oesophageal cancer
• Mallory Weiss tears, which are tears in the oesophagus as a result of violent vomiting 
• Severe inflammation (gastritis or esophagitis)
• Erosion of your stomach lining (acute hemorrhagic erosive gastropathy)

Signs and symptoms of melaena

With melaena, you would likely have other symptoms alongside the characteristic black tarry stool as melaena would most likely be a result of upper gastrointestinal bleeding. Signs and symptoms of upper gastrointestinal bleeding include:^{2, 3}

• Vomiting blood
• Coffee ground vomit (vomit has a dark coffee-like appearance)
• Abdominal pain
• Difficulty swallowing
• Dizziness
• Drowsiness
• Signs of liver disease, such as jaundice
• Rectal bleeding is more associated with lower GI bleeds but can still occur in a patient with upper GI bleeding 

Diagnosis of melaena

To diagnose if you have melaena, your healthcare will enquire about your past medical history, the symptoms you experience and the nature of your stool (odour, colour, etc). Your healthcare provider will send your stool for testing and might also request a blood test to determine the amount of blood lost and the cause. Your healthcare provider may conduct an oesophagogastro-duodenoscopy (OGD) and request a CT scan and CT angiogram.

Management and treatment for melaena

As melaena is often associated with upper gastrointestinal bleeding, it becomes a medical emergency. It is important to identify the cause as the management is different. However, the initial management is the same: ^3, 

• Patients with upper GI bleeding are often very unwell so the measurements of your vital signs, such as your temperature, pulse, blood pressure, and respiratory rate, would be immediately required 
• Immediate blood transfusions would also be required because the bleeding in the upper GI is often quite significant, needing urgent replacement. You would also have blood tests conducted to help monitor the extent of the bleeding and also help in identifying the cause 
• A detailed history in particular your past medical history and also a list of medications you take may also help in narrowing down the cause 
• An investigation called an esophagogastroduodenoscopy (OGD) would also be needed to identify the cause as this takes accurate images of your upper GI tract

If it is suspected the cause of the bleeding is due to variceal bleeding, then you would first be given a medication called terlipressin. Then you would have a procedure called endoscopic band ligation where an endoscopy is used to place rubber bands around the bleeding vessels to stop them from bleeding. You would then be heavily monitored as you recover. In someone with non-variceal bleeding who has a bleeding stomach ulcer, an endoscopy would be performed; however, this would be followed by medication with drugs called proton pump inhibitors such as omeprazole. Antibiotics would also be given to prevent infection.

FAQs

How common is melaena?

Upper GI bleeds occur in 134/1000 people, many of whom will have melaena.⁴

How can I prevent melaena?

You can prevent melaena by preventing the conditions that lead to upper gastrointestinal bleeding such as stomach and duodenal ulcers and varices. Methods to prevent this from occurring include:^5,6 

• Avoiding regular use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen as these can cause ulcers
• Reducing consumption of spicy foods
• Reducing alcohol intake to avoid varices but also to avoid bleeding from stomach cancer
• Avoiding smoking to prevent cancer anywhere within the GI tract 

When should I see a doctor?

If you notice any change in the nature of your stool (colour, odour) or if you are experiencing any symptoms of melaena, it is best to seek medical advice immediately as it could be a sign of upper gastrointestinal bleeding. It is advisable to go to the emergency department so that you can be properly investigated and receive medical treatment in the event you are having upper GI bleeding.

Summary

In summary, melaena is one of the striking and classical signs of upper GI bleeding. Melaena refers to the appearance of dark, tarry stools which occurs as a result of bleeding in the gastrointestinal (GI) tract (your mouth, oesophagus, stomach, and small and large intestines) If you notice any changes in the odour or appearance of your stool and if you are experiencing any symptoms of melaena, please seek prompt medical attention as upper GI bleeding is a medical emergency.