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'''For patient information click [[{{PAGENAME}} (patient information)|here]]'''
{{DiseaseDisorder infobox |
{{DiseaseDisorder infobox |
   Name        = Melena |
   Name        = Melena |
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{{Melena}}
{{Melena}}
{{CMG}}
==[[Melena overview|Overview]]==
==[[Melena historical perspective|Historical Perspective]]==
==[[Melena pathophysiology|Pathophysiology]]==
==[[Melena causes|Causes]]==
==[[Melena epidemiology and demographics|Epidemiology and Demographics]]==


{{CMG}}
==[[Melena risk factors|Risk Factors]]==
==Overview==
'''Melena''' or ''melaena'' refers to the black, "tarry" [[feces]] that are associated with gastrointestinal [[hemorrhage]]. The black color is caused by oxidation of the [[iron]] in [[hemoglobin]] during its passage through the [[ileum]] and [[colon (anatomy)|colon]].


==Melena vs. hematochezia==
==[[Melena natural history, complications and prognosis|Natural History, Complications and Prognosis]]==
Bleeding originating from the lower GI tract (such as the [[sigmoid colon]] and [[rectum]]) is generally associated with the passage of bright red blood, or [[hematochezia]], particularly when brisk.  Blood acts as a [[cathartic]] agent in the intestine, promoting its prompt passage.  Only blood that originates from a high source (such as the [[small intestine]]), or bleeding from a lower source that occurs slowly enough to allow for oxidation, is associated with melena.  For this reason, melena is often associated with [[hemorrhage]] in the [[stomach]] or [[duodenum]] ([[upper gastrointestinal tract]]), for example by a [[peptic ulcer]]. A rough estimate is that it takes about 14 hours for blood to be broken down within the intestinal lumen; therefore if transit time is less than 14 hours the patient will have hematochezia and if greater than 14 hours the patient will exhibit melena. One often-stated rule of thumb is that melena only occurs if the source of bleeding is above the [[ligament of Treitz]].


==Diagnosis==
==Diagnosis==
Patients present with signs of anemia.  The presence of blood must be confirmed with either a positive hemoccult slide on rectal exam, frank blood on the examining finger, or a positive stool guaiac from the lab.  If a source in the upper GI tract is suspected, an [[upper endoscopy]] can be performed to diagnose the cause.  Lower GI bleeding sources usually present with hematochezia or frank blood.  A test with poor sensitivity/specificity that may detect the source of bleeding is the tagged red blood cell scan, whereas mesenteric angiogram is the gold standard. Hence, the commonly referenced quote goes as follows: "when you go the bathroom it spells melana in the toilet."


==Differential diagnosis of causes of melena==
[[Melena history and symptoms|History and Symptoms]] | [[Melena physical examination|Physical Examination]]  | [[Melena laboratory findings|Laboratory Findings]] | [[Melena x ray|X Ray]] | [[Melena CT|CT]] |  [[Melena other imaging findings|Other Imaging Findings]] | [[Melena other diagnostic studies|Other Diagnostic Studies]]
The most common cause of melena is [[peptic ulcer]] disease. Any other cause of bleeding from the upper gastro-intestinal tract, or even the ascending colon, can also cause melena.  Melena may also be a sign of drug overdose if a patient is taking anti-coagulants, such as warfarin. A less serious, self-limiting case of melena can occur in newborns two to three days after delivery, due to swallowed maternal blood.


==Treatment==
==Treatment==
Urgent care however is required.
[[Melena medical therapy|Medical Therapy]] | [[Melena surgery|Surgery]] | [[Melena primary prevention|Primary Prevention]] | [[Melena secondary prevention|Secondary Prevention]] |  [[Melena cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] |  [[Melena future or investigational therapies|Future or Investigational Therapies]]
 
==Case Studies==
[[Melena case study one|Case #1]]


==Related Chapters==
==Related Chapters==

Revision as of 15:37, 5 September 2012

For patient information click here Template:DiseaseDisorder infobox

Melena Microchapters

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Overview

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Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

X Ray

CT

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

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Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Historical Perspective

Pathophysiology

Causes

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | X Ray | CT | Other Imaging Findings | Other Diagnostic Studies

Treatment

Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case #1

Related Chapters

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