Surgical Emergencies
Question 112 of 180
A 70 year old man presents to the Emergency Department with a 2 day history of per rectum bleeding. What is the most common cause of significant lower GI bleeding in adults?
Answer:
The most common cause of significant lower GI bleeding in adults is diverticular disease. In descending order of frequency, this is followed by angiodysplasia, upper GI bleeding, cancer or polyps, rectal disease, and inflammatory bowel disease.Lower Gastrointestinal Bleed
Surgical Emergencies
Last Updated: 8th September 2021
Differentials
Common causes:
- Diverticular disease
- Colonic angiodysplasia
- Ischaemic colitis
- Crohn's disease
- Ulcerative colitis
- Infectious colitis
- Colorectal cancer
- Internal haemorrhoids
- Anal fissure
- Colonic polyps
Uncommon causes:
- Meckel's diverticulum
- Radiation-induced telangiectasia
- Dieulafoy's lesion
- Aorto-enteric fistula
- Vasculitis
- Hereditary haemorrhagic telangiectasia
- Blue rubber bleb nevus syndrome
- Anal cancer
- Rectal ulcer
- Rectal varices
- Post-polypectomy bleeding
- Non-steroidal anti-inflammatory drug (NSAID) colopathy
- Upper GI bleeding (rapid transport)
- Prostate biopsy site bleeding
- Endometriosis
Assessment
Initial evaluation of the patient includes assessment of the severity of the gastrointestinal (GI) bleeding and of the risk to the patient. Severe bleeding is defined as acute bleeding with either postural hypotension and/or a significant drop in haematocrit (>6% to 8%) from baseline.
The history helps determine the possible source of the GI bleeding and also assesses the severity of the bleeding.
The following should be determined from the history:
- Age of patient.
- Diverticular disease and angiodysplasia are more common in older patients (age >65 years)
- Duration of the bleeding.
- The bleeding can be either an acute, intermittent, or chronic event.
- Colour of the blood.
- The colour of the blood in the stool, and whether the blood coats the stool or is mixed with the stool, helps to localise the site of bleeding
- Associated dizziness or syncope.
- Presence of syncope may suggest that the patient has lost a significant amount of blood.
- Other associated symptoms, include abdominal pain, constipation, rectal pain, weight loss, diarrhoea, and tenesmus.
- The presence of abdominal pain and diarrhoea with haematochezia (bright red rectal bleeding) suggests colitis, either inflammatory or ischaemic, while angiodysplasia does not usually cause pain.
- Change of bowel habit, tenesmus, or weight loss may be seen in colorectal cancer or inflammatory colitis.
- Specific enquiry about the presence of inflammatory bowel disease, internal haemorrhoids, diverticular disease, angiodysplasia, aspirin/NSAID use, recent use of antibiotics, and recent travel is required.
Physical examination should include:
- Assessment of vital signs.
- Assess for postural hypotension. Presence of haemodynamic instability suggests presence of severe bleeding.
- Palpation of the abdomen for tenderness, hepatomegaly, or abdominal masses.
- Hepatomegaly or abdominal masses prompt evaluation for colorectal cancer as the source of the bleeding
- Rectal examination.
- It is essential to perform a rectal examination in all patients with lower GI bleeding to exclude a palpable rectal mass. If an anal fissure is suspected and rectal examination would be too painful, consideration of examination under anaesthesia is required. The colour of the stool may suggest the location of blood loss.
Initial tests should include:
- FBC (with major attention to hematocrit, WBC count, and platelet count), prothrombin time, and thromboplastin time are measured.
- Patients with acute bleeding, ongoing active bleeding, or severe bleeding require blood group and cross-matching.
- ESR and CRP may be elevated in patients with inflammatory bowel disease.
- Stool studies, such as stool WBC, stool culture, and microscopic examination for ova and parasites, are obtained in patients with haematochezia (bright red rectal bleeding) associated with acute diarrhoea.
Further investigations may include:
- Anoscopy
- Colonoscopy
- Angiography
- CT abdomen
- Oesophagogastroduodenoscopy (OGD)
Management of severe bleeding
High-risk patients presenting with severe lower GI bleeding need to be identified and aggressively resuscitated. High-risk patients include those with:
- Haemodynamic instability
- Serious comorbid states
- Persistent bleeding
- A requirement for multiple blood transfusions. (Requirement for 6 units is an indicator that the bleeding will not resolve spontaneously, 10 units suggests increased mortality.)
Treatment includes:
- Resuscitation with IV fluids and blood transfusions, and correction of any underlying coagulopathy or thrombocytopenia is required.
- Coagulopathy or thrombocytopenia is corrected with either fresh frozen plasma or platelets, respectively.
- Two large-bore peripheral IV catheters or a central venous line are necessary.
- Blood transfusion need is determined by the patient's age, rate of bleeding, and the presence of comorbid states (such as coronary artery disease, cirrhosis, or chronic obstructive lung disease).
- The presence of orthostatic hypotension, a drop in haematocrit >6%, or continuous active bleeding warrants admission to an ICU for close observation.
- Anticoagulant drugs should be withheld. Consider vitamin K and prothrombin complex concentrate to reverse the anticoagulant effect of warfarin before colonoscopy if the international normalised ratio (INR) is >2.5.
- The American College of Gastroenterology, and others, recommend colonoscopy as the initial diagnostic procedure. Colonoscopy can be therapeutic as well as diagnostic, using argon plasma coagulation, epinephrine injections, and clips.
- Computed tomography (CT) angiography can be used to identify the site of blood loss prior to colonoscopy.
- Transcatheter arteriography and intervention may be more appropriate in an unstable patient.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
