Black Poop

Poop (faeces) is a product left after the digestion of food and is normally brown in colour. Black poop is an indication of an underlying health issue, but can also be the result of the colour from the food ingested. Black poop can result from the intake of the following:

• Iron supplementation
• Blueberries
• Blood sausage
• Activated charcoal
• Medication consisting of Bismuth

Black or tarry poop with a foul smell is a symptom of health issues in the body. Tarry stool is an indication of bleeding in the upper gut. Lower gut bleeding is indicated as red-coloured stools with fresh blood. Black poop mostly is an indication of: 

• Peptic ulcer
• Gastritis
• Colorectal cancer
• Intestinal polyps
• Constipation¹

What does black stool mean?

Normal stool is brown - this is due to digested food mixing with bile. Black or tarry poop usually is indicative of the colour of food or medication taken into the body, but internal bleeding in the gut can also result in black poop.

The condition is called Melaena, which is when the colour of the stool is tarry and black. When blood is seen coming from the anus, with or in the stool, the condition  is known as haematochezia. 

The gut  is divided into upper and lower parts by the ligament of Treitz, a suspensory ligament of the duodenum. Bleeding above the ligament of Treitz is represented as melaena, and below the ligament it is represented as haematochezia.

When a person ingests blood, his poop will be tarry for 4-5 days. It takes 50 ml of blood in the intestine to change the colour of poop into black, red or maroon. Malaenic stools need not  indicate bleeding - presence of blood in the small intestine or caecum can also cause tarry stools if the blood retaining in the region is long. Upper gut bleeding is the most common cause of melaena.²

Causes of black poop

Adult 

Melaena or tarry stools are common in adults and children when taking certain foods. Melaena can also result from different conditions. Causes of melena in adults are:

1. Duodenal ulcer- disruption in the surface of the mucosa of the duodenum
2. Oesophageal or gastric varices - abnormal and enlarged  vessels in the tube that connects the throat and stomach
3. Gastric ulcer- open sores that develop in the lining of the stomach
4. Gastritis- inflammation of the lining of the mucosa
5. Portal hypertensive gastropathy- wide range of gastric lesions in the gastric mucosal lining
6. Angiodysplasia - abnormal, dilated and tortuous blood vessels in the mucosa and submucosal layers of the GI tract
7. Oesophagitis- inflammation in the lining of the oesophagus
8. Mallory–Weiss syndrome- a common cause of gut  bleeding which is characterised by longitudinal mucosal lacerations (Mallory-Weiss tears) located at the gastroesophageal junction
9. Gastric tumours- irregular and uncontrolled proliferation of cells in the lining of the gastric mucosa
10. Foreign body ingestion
11. Gastric- antral vascular ectasia (GAVE) - also known as watermelon stomach.  Blood vessels in the stomach become fragile and become susceptible to rupture and bleeding. Its endoscopic  presentation resembles stripes similar to watermelon, hence the name
12. Post-surgical bleeds
13. Haemobilia - bleeding from the biliary tract 
14. Haemosuccus pancreaticus - bleeding from the pancreatic duct
15. Cameron lesions - bleeding ulcers occurring at the site of a hiatal hernia.³

 Some medications can also cause black stool - they are:

1. Bismuth - the active component in Bismuth activates with sulphur in the saliva, producing bismuth sulphide, a black substance that comes out of the body as black poop
2. Iron supplementation - unabsorbed iron comes out of the body in the colour of greyish or greyish-black, due to the active component Bismuth Subsalicylate
3. Aspirin & Non-steroidal anti-inflammatory drugs- pain killers can cause stomach ulcers and gut bleeding that results in tarry stool or melaena⁴

The various reasons for black stool in children are:

1. Oesophagitis- inflammation of lining of oesophagus 
2. Gastritis- inflammation of gastric mucosa
3. Peptic ulcer- open sores that develop in the inside lining of the stomach and upper portion of the small intestine
4. Oesophageal or gastric varices³

Infants

Newly born children have black poop for a few days. It is due to the blood ingested by the infant  during delivery. Their poop has to be checked if it has maternal or foetal blood. There is no need to worry if it is maternal blood. If it is foetal blood, care has to be administered immediately to rule out any bleeding within the body.⁵

Complications

Continuous  bleeding has to be controlled. When it is occurring in the internal organs like the gut, melaena helps in identifying the problem. If not addressed, continuous loss of blood may lead to:

• Respiratory Distress
• Myocardial Infarction
• Infection
• Shock
• Death⁶

Diagnosis of gastroesophageal bleeding

When one is reporting about melaena, proper history followed by examination techniques should be performed to confirm the site of bleeding. These are:

1. Upper GI endoscopy
2. Lower GI endoscopy/colonoscopy
3. Deep small bowel enteroscopy
4. Push enteroscopy
5. Nuclear scintigraphy
6. CT angiography
7. Standard angiography
8. Meckel scan³

Prevention

Avoiding the practices which cause gut bleeding can prevent melaena. These are:

1. Avoid the usage of medications like aspirin, and NSAIDS that cause gastric bleeding
2. Do not  smoke as smoking causes fragile vessels and increased chances of bleeding
3. Do not  drink alcohol or coffee
4. Eat healthy
5. Lead a healthy lifestyle
6. Drink extra liquids

Treatment and home remedies

Treatment

Gut bleeding can be addressed at two levels:

Intensive care unit chronic uncontrolled bleeding

If the case is not an emergency, it can be treated in a general medical ward.

Treatments include:

1. IV Fluids
2. Blood transfusions
3. RBC  transfusions
4. Platelet transfusions
5. Prothrombin complex concentrate

Medications include:

1. Proton pump inhibitors - to reduce gastric acid secretion to identify the site of bleeding
2. Prokinetic agents - to improvise the visualisation  at the time of endoscopy
3. Vasoactive medications - to treat variceal bleeding
4. Antibiotics- to treat any underlying infection

Surgery has to be done when there is profuse bleeding which is not being treated by the conventional methods mentioned above.³

Home remedies

Home remedies are not advised - milk mixed with turmeric is generally used to treat any infections in the stomach.³

When to seek medical attention

Black and tarry stools are a sign of a serious underlying condition. One has to seek medical intervention as soon as possible whenever noticed - they will take a proper history and send for diagnostic tests to confirm the problem. The health professional will ask about the history of food and medications which might be causing black poop. If no such history is elicited, he may conduct diagnostic tests like blood tests, colonoscopy, and endoscopy, to identify the issues in the gut. Irrespective of age, it is best to consult a doctor whenever one notices black poop.^1,2

Summary

Black poop requires medical intervention and observation at the earliest. When the individual is taking any food or medication resulting in black-coloured poop, then they need to be kept under observation. The presence of black poop needs immediate medical attention to rule out its causes.