Melena History
Author – Dr Tachakrit Tachatirakul Editor – Dr Tachakrit Tachatirakul
Last updated 06/05/24
Table of Contents
Introduction
Melaena is one of the findings which may be a complaint to see a GP or ED. Alternatively it could also be one of the signs found in secondary care as an incidental finding on a PR exam.
Melaena are black tarry stools, they are also very foul-smelling. The colour and the texture of the melaena is associated with GI bleeding (frequently but not always upper GI bleeding). This is due to the breakdown of Haemoglobin in the digestive tract.
Presence of melaena alone may suggest gastrointestinal bleeding (especially of the upper gastrointestinal tract) but it does not tell you why the patient may be bleeding. It is important to ask the patient of their history thoroughly to narrow down the likely causes.
Presenting Complaint
Try to expand on the presenting complaint by asking the following questions:
Timing – Duration? Constant? Intermittent?
Associated symptoms – Melaena may be accompanied with or without pain. Haematemesis may also be present as well as reduced appetite. Coffee ground vomiting increases the likelihood that it is indeed an upper GI bleed. The appearance of the coffee ground is due to digestion of blood in the upper GI tract.
Precipitating factors?
Anything make it better?
Anything make it worse?
Common Causes of Melaena
It is important to demonstrate to the examiner that you are aware of these common causes and establish which system to click into.
| Lorem | Ipsum |
|---|---|
Bleeding Peptic Ulcer | Think of NSAIDS, history of reflux, H.pylori, past ulcers, abdominal pain (duodenal ulcers get better with food, while gastric ulcers get worse) |
Variceal Bleed | Think chronic alcohol consumption, look for signs of alcohol withdrawal which may be accompanying the presentation. Look for stigmata of chronic liver failure:
Gynecomastia, palmar erythema, more than 3 spider naevia, caput medusae, ascites, oedema of lower limbs (in severe cases upper limbs due to albumin deficiency). Note that asterixis is a late sign of liver failure (due to hepatic encephalopathy) |
Upper GI Malignancies | Symptoms include dysphagia, vomiting, haematemesis, change in bowel habit, and unintentional weight loss.
Risk factors/signs of cancer to be aware of include:
high alcohol intake, smoking, cachexia, may be painless or painful, cancer B symptoms such as unintentional weight loss (not attributable to change in fluid status) and night sweats. |
Background
In any history you will ask about past medical history, medications, allergies, social history, and family history. In a history about melaena you can show how much you know about the various causes by explicitly asking about the following things:
Past Medical History
Key questions to ask include:
- Does the patient have frequent bleeding problems such as nosebleeds, haematuria or excessive bleeding from cuts? Any possibility of coagulation disorder?
- Does the patient have a history of any ACS, stroke or vascular disease which means that they are put on aspirin/other anti-coagulants, these increase the risk of bleeding and depending on risk and benefits may suggest holding these medications.
- Is the patient on a DOAC (such as apixaban or edoxaban) for AF or other indications?
- Do they have a metal valve or other implant which means they are put on a blood thinner such as warfarin. This does increase the risk of bleeding.
- What is the mental health history of the patient? Are they on anti-depressants? SSRIs such as sertraline are associated with increased risk of upper GI bleeding.
- Does the patient have cancer, as this can predispose to GI bleeding?
- Does the patient have liver problems? The liver produces coagulation factors. Someone who has liver failure may not be able to produce coagulation factors normally.
- Is there a possibility of Mallory-Weiss syndrome, is there any signs of bulimia or otherwise repeated vomiting?
- History of reflux? As stomach acid can irritate the lining of the oesophagus and predispose to a bleed.
- Any recent abdominal surgery? Bleeding may be a complication of the surgery. Surgical opinion and correction may be needed in severe cases.
Drug History
The following drug groups may increase risk of upper GI bleeding
- NSAIDs: e.g. ibuprofen, naproxen
- SSRIs e.g. sertraline, citalopram, fluoxetine
- Anticoagulants
- PPIs – may suggest that the patient may have gastroesophageal reflux
- Anything which affects liver metabolism in patients with warfarin.
MLA Tip 💡
Note that taking Iron supplements, may give a false positive of melaena due to colouring stools black!
Family History
- Coagulation disorders (Haemophilias, vWF disease)
- History of Cancer?
- History of dyspepsia, symptoms of upset stomach, pain, indigestion, bloating. This can predispose to bleeding due to irritation of stomach/esophageal lining.
Social History
Alcohol – increased risk of bleeding from (varices in long term use as well as UGI cancer); Chronically may increase risk of bleeding due to liver failure
Smoking – increased risk of bleeding secondary to cancers in GI which can cause bleeding
Occupation – Lung cancer risk may be higher in certain individuals, it is known to metastasize to liver, and in severe cases cause liver failure, decreasing production of coagulation factors. (Less common but useful to keep in mind)
Diet – can precipitate fatty liver disease
Other – Tattoos, hepatic viruses (risk is increased in IV drug users)
Demographics can also play an important part:
Age – Suspicion of cancer is higher in older patients.
Cultural background – In southeast asia a dish made from fermented river fish can contain liver flukes, this in turn can cause hepatitis and in the long term may lead to impaired ability to produce coagulation factors)
Examination
When examining the patient, you should keep your differentials in mind and look for signs that confirm or refute your potential.
- https://www.rcp.ac.uk/file/12899/download