UPPER GASTROINTESTINAL BLEEDING

Bleeding from the gastrointestinal tract may be caused by lesions located in the foregut (oesophagus, stomach and duodenum), midgut (small bowel up to mid transverse colon) and hindgut (distal colon and rectum). The bleeding  may be acute when the patient presents with hypovolaemia, or chronic when the clinical picture is that of symptomatic anaemia. The common causes of acute upper gastrointestinal haemorrhage are:

• •         chronic peptic ulceration;
• •         NSAID-induced bleeding;
• •         oesophagogastric varices.

Irrespective of the cause, the vomited blood (haematemesis) may be fresh (in severe active bleeding as from ruptured oesophageal varices) or chemically altered (because acid digestion simulates 'coffee grounds'). Extensive gastrointestinal bleeding also gives rise to the passage of black  foul-smelling liquid faeces known as melaena. Patients taking NSAIDs have a threefold risk of gastrointestinal haemorrhage, surgery and death compared with non-users. The risk from bleeding is greatest in:

• •         first few months of treatment;
• •         the elderly (> 65 years);
• •         patients with concomitant steroid use;
• •         patients with a previous history of gastrointestinal events.

Of all the NSAIDs known to cause bleeding or perforation, aspirin produces the most damage. There is some evidence that the newer NSAIDs (e.g. nabumetone) that selectively inhibit cyclooxygenase-2 are less damaging to the gastroduodenal mucosa and hence significantly less ulcerogenic but they appear to be less effective clinically in relieving pain. The other problem with NSAIDs is the development of non-specific ulceration of the upper small intestinal mucosa, which can bleed and perforate. Gastrointestinal haemorrhage may be caused by both benign and malignant tumours. However, acute haemorrhage is more commonly associated with benign  lesions such as neurofibromatosis and mesenchymal (smooth muscle) tumours. Malignant tumours (carcinoma and lymphomas) more usually cause chronic blood loss with the development of iron-deficiency anaemia, although massive bleeding may be precipitated by combination chemotherapy (see later). Life-threatening bleeding or perforation from necrosis of the tumour may complicate chemotherapy for gastrointestinal tumours,  especially lymphomas. Stress ulceration is usually encountered in critically ill patients nursed in the intensive care unit, although its incidence has declined.

Other causes of acute upper gastrointestinal bleeding include Dieulafoy's lesion, portal hypertensive gastropathy and watermelon stomach.

•         Dieulafoy's lesion (exulceration simplex) consists of a nodule containing a visible vessel covered with normal mucosa. Treatment is by endoscopic electrocoagulation or sclerotherapy.

•         Portal hypertensive gastropathy develops in some patients with cirrhosis and portal hypertension with progressive liver damage and affects predominantly the fundus but may be generalized.

•         Diffuse vascular ectasia (watermelon stomach) consists of ectatic mucosal sacculated vessels in the lamina propria traversing the antrum and sometimes the duodenum. The endoscopic appearance bears some resemblance to the stripes of a watermelon. The bleeding is often recurrent requiring multiple transfusions. Portal hypertensive gastropathy and diffuse gastric vascular ectasia are probably related.

The treatment of acute upper gastrointestinal haemorrhage is based on the following principles.

•         Resuscitation: volume replacement with crystalloids, colloids and blood.

•         Early endoscopy: for diagnosis and endoscopic control of bleeding.

•         Combined management by gastroenterologists and surgeons with early recourse to surgery if bleeding continues or recurs.

Sometimes there is clear evidence of upper gastrointestinal bleeding without apparent cause. In these patients, mesenteric angiography and small-bowel enteroscopy often locate the source of the bleeding.

Chronic gastrointestinal bleeding is unnoticed by the patient and for this reason is referred to as occult. The constant drain results in depletion of iron stores and thus the development of iron-deficiency (hypochromic microcytic) anaemia. When discovered this must always be investigated as follows:

•         faecal occult blood;

•         upper gastrointestinal endoscopy;

flexible sigmoidoscopy and barium enema or colonoscopyif upper gastrointestinal endoscopy is negative. Carcinoma of the caecum and ascending colon most commonly presents as iron-deficiency anaemia as does carcinoma of the stomach.