The medical term Melena for black tarry stools, is derived from greek ‘melanos’ which means dark or black (think about melanin skin pigment, or Melanie spice from Spice Girls). Black color happens due to slow oxidation of hemoglobin to black acid-hematin by gastric acid & intestinal bacterial enzymes. Because this is slow, a massive Upper GI bleed can still present as bloody red stools due to lack of oxidation time. Investigating any melena starts with an upper GI scope or EGD – A clean-looking EGD usually leads to a Video Capsule Endoscopy (VCE) study to look farther than the duodenum, and if suspcious looking leads to push-enteroscopy to evaluate upper small bowel (jejunum) for bleeds.
This post is to raise awareness about swallowed nose bleeds (epistaxis) being mistaken as melena from upper GI bleed. Give this possibility a thought when upper GI scope shows no bleeders or lesions to explain melena. This can be especially true for posterior nose bleeds that bleed backwards into the pharynx & get swallowed unbeknownst to the patient. Even if nose bleeds are visible, the patient may not make that epistaxis-melena connection and so it’s upto you to specifically ask about nose bleeds in any case of black tarry stools. A good oral exam might reveal blood tricking from the back of the throat, patient might report metallic taste if you ask and might even have intermittent visible nose bleed history.
So keep an index of suspicion for this in cirrhotics, people on anticoagulants / anti-platelets or bleeding disorders. This study listed on Pubmed found 20 out of 1249 cirrhotic patients with GI bleed actually had nose bleeds as the cause. In Cirrhotics, in addition to fooling us about a GI bleed, swallowed nose bleeds can be significant enough to cause Hepatic Encephalopathy. Here’s an interesting case report on a patient with both – Epistaxis PLUS Upper GI bleed.
P.S: Ever wondered if blood-drinking vampires have normal, physiologic melena ? 🧛🏽♂️🦇😉
