Differentials
Common
Diverticular disease
History
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); abdominal examination is usually normal; rectal examination may reveal bright red blood or blood clots, may be indistinguishable from colonic angiodysplasia but bleeding is usually more profuse and more likely to cause haemodynamic instability
1st investigation
Colonic angiodysplasia
History
typically over 60 years; intermittent, mild, or severe episodes of painless haematochezia (bright red rectal bleeding), may be history of end-stage renal disease, von Willebrand's disease, aortic stenosis, or anticoagulant therapy
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); signs and symptoms of anaemia may be present; abdominal examination is usually unremarkable, rectal bleeding may be indistinguishable from diverticular disease but bleeding usually less severe and less likely to cause haemodynamic instability
1st investigation
- FBC:
haemoglobin normal or low
- platelets:
normal or rarely thrombocytopenia in severe bleeding
- clotting studies:
usually normal
- colonoscopy:
angiomas may be visualised: 5 to 10 mm cherry red, ectatic blood vessels radiating from a central vessel
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Ischaemic colitis
History
age typically over 60 years, sudden-onset lower abdominal cramping, diarrhoea, and self-limited haematochezia (bright red rectal bleeding); may be history of haemodialysis, hypertension, hypo-albuminaemia, diabetes mellitus, constipation-inducing drugs
Exam
lower abdominal tenderness; presence of peritoneal signs/absence of bowel sounds may suggest trans-mural infarction or perforation
1st investigation
Other investigations
- colonoscopy:
petechial haemorrhages, oedema, ulceration of colonic mucosa
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Crohn's disease
History
age at diagnosis usually under 50 years, chronic diarrhoea (usually non-bloody); symptoms can be intermittent; tenesmus; gradual onset of symptoms; weight loss[52]
Exam
may appear pale, malnourished; right lower quadrant abdominal tenderness; may be abdominal mass, oral ulceration, peri-anal skin tags, fistulae, abscess, or sinus tract; life-threatening bleeding rare
1st investigation
Other investigations
Ulcerative colitis
History
age at diagnosis usually under 50 years, haematochezia (bright red rectal bleeding); chronic diarrhoea; lower abdominal pain; faecal urgency; tenesmus; episodes of constipation; weight loss; acute arthropathy; symptoms can be intermittent; history of primary sclerosing cholangitis
Exam
pallor, may appear malnourished, abdominal tenderness, erythema nodosum or pyoderma gangrenosum, uveitis or episcleritis, fever may be present, life-threatening bleeding rare
1st investigation
- FBC:
variable degree of anaemia, leukocytosis
More - platelets:
usually normal; may be elevated
- clotting studies:
normal; or coagulopathy present
- colonoscopy:
rectal involvement, continuous uniform involvement, loss of vascular marking, diffuse erythema, mucosal granularity, fistulas (rarely seen), normal terminal ileum (or mild 'backwash' ileitis in pancolitis). Biopsies are diagnostic.
More - CRP:
elevated
More - erythrocyte sedimentation rate:
elevated
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Other investigations
Infectious colitis
History
acute diarrhoea, abdominal pain, may be a history of travel to regions with higher risk of infectious diarrhoea
Exam
abdominal tenderness may be present, fever
1st investigation
- stool studies:
stool culture: may reveal the specific pathogen; stool white blood cell count: may be elevated; tests for ova and parasites may be positive
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Other investigations
Colorectal cancer
History
typically age is over 40 years; rectal bleeding; weight loss; change in bowel movements; tenesmus, abdominal pain
Exam
palpable mass may be present in the abdomen; rectal mass may be felt on digital rectal examination
1st investigation
- colonoscopy:
friable mass in the colon may be seen and biopsy is diagnostic.
- quantitative faecal immunochemical tests:
positive
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Other investigations
- CT abdomen:
extent of disease, metastatic lesions
Internal haemorrhoids
History
self-limited, intermittent, painless bright red rectal bleeding that may be chronic or intermittent; constipation may also be present; blood may be covering the stool
Exam
general examination is usually normal
1st investigation
- anoscopy:
internal haemorrhoids visualised
Other investigations
Anal fissure
History
rectal bleeding (usually seen on wiping) and severe peri-anal pain on defecation
Exam
fissure may be visible when parting buttocks, most commonly in the posterior midline
1st investigation
- none:
usually a clinical diagnosis in younger people
- examination under anaesthetic:
fissure present
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Other investigations
Colonic polyps
History
typically age is over 40 years; may be a family history of colonic polyps, colon cancer, or familial adenomatous polyposis or Gardner's syndrome; rectal bleeding, may be otherwise asymptomatic, change in bowel movements, abdominal pain
Exam
normal abdominal examination
1st investigation
- colonoscopy:
polyps visible
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Other investigations
Uncommon
Meckel's diverticulum
History
occurs in children or young adults; painless melaena or bright red blood per rectum (described as 'currant jelly') is the major symptom
Exam
abdominal tenderness and an abdominal mass may be present
1st investigation
- FBC:
haemoglobin normal or low
- platelets:
usually normal
- clotting studies:
usually normal
- radionuclide imaging:
shows an uptake due to technetium binding to the ectopic gastric parietal cells
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Other investigations
- mesenteric angiography:
extravasation of the dye at the bleeding site in the terminal ileum
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Radiation-induced telangiectasia
History
history of radiotherapy for abdominal cancers; diarrhoea, rectal pain or urgency, faecal incontinence, and obstructed defecation may also occur; symptoms typically 9 weeks to 4 months after radiation injury; bleeding may be persistent or severe
Exam
abdominal examination is non-contributory; rectal examination may reveal bright red blood per rectum
1st investigation
- FBC:
haemoglobin usually normal
- platelets:
usually normal
- clotting studies:
normal; or coagulopathy present
- colonoscopy:
mucosal pallor with friability and telangiectasias; telangiectasias may be large and multiple
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Other investigations
Dieulafoy's lesion
History
painless haematochezia (bright red rectal bleeding); bleeding may be severe
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); abdominal examination is normal; rectal examination may reveal bright red blood or blood clots
1st investigation
- FBC:
haemoglobin usually low
- platelets:
usually normal
- clotting studies:
normal; or coagulopathy present
- colonoscopy:
a superficial blood vessel (either actively bleeding or non-bleeding with stigmata of recent bleed), may be seen in the colon at the site of bleeding
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Other investigations
Aorto-enteric fistula
History
herald bleed may occur; history of aortic graft, melaena, and haematemesis; fever may be present
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); abdominal tenderness, bleeding more likely to be profuse with haemodynamic instability
1st investigation
- FBC:
haemoglobin usually low
- platelets:
usually normal, may be low
- clotting studies:
usually normal, may be coagulopathy with severe bleeding
- oesophagogastroduodenoscopy (OGD):
bleeding from the second or third part of duodenum may be visualised
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Other investigations
- CT scan of abdomen:
typical findings: peri-graft fluid, soft tissue attenuation, ectopic gas, pseudo-aneurysm, or focal ischaemic bowel
Vasculitis
History
history of vasculitis (e.g., systemic lupus erythematosus [SLE], polyarteritis nodosa) abdominal pain, GI bleeding, nausea, vomiting, and haematemesis
Exam
abdominal tenderness may be present, stigmata of the underlying vasculitic condition may be present (e.g., malar butterfly rash in patients with SLE)
1st investigation
- FBC:
haemoglobin may be normal; blood film may be consistent with an iron deficiency anaemia, may be leukopenia
- platelets:
usually normal; may be thrombocytopenia
- clotting studies:
normal; or coagulopathy present
- serological markers (e.g., antinuclear antibodies [ANA], anti-neutrophil cytoplasmic antibodies [ANCA]):
may be positive
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Other investigations
- CT scan of abdomen:
may show thickening of the wall of the colon or the small intestine
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Hereditary haemorrhagic telangiectasia
History
epistaxis; family history of hereditary haemorrhagic telangiectasia
Exam
multiple telangiectasia on lips, oral cavity, fingers, nose; may have signs related to complications of arteriovenous malformations in lungs, liver, brain
1st investigation
- FBC:
haemoglobin usually normal or low
- platelets:
usually normal
- clotting studies:
normal; or coagulopathy present
- oesophagogastroduodenoscopy:
telangiectasia present in the upper GI tract
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Other investigations
- colonoscopy:
telangiectasia present in the lower GI tract
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Blue rubber bleb nevus syndrome
History
multiple skin venous malformations often present at birth or diagnosed in early childhood; bleeding more likely as a young adult; melaena and haematemesis; fatigue may be present
Exam
cutaneous lesions (protuberant dark blue vascular tumours) may be seen; skeletal bowing may be present if there is bone involvement
1st investigation
- FBC:
haemoglobin usually normal
- platelets:
usually normal
- clotting studies:
normal; or coagulopathy present if liver cirrhosis is present
- colonoscopy:
protuberant dark blue vascular lesions are seen in the GI tract
More - oesophagogastroduodenoscopy:
protuberant dark blue vascular lesions are seen in the GI tract
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Other investigations
Anal cancer
History
rectal bleeding, rectal pain, or feeling of a rectal mass may be present
Exam
inspection of the peri-anal area and digital rectal examination may reveal the presence of anal mass, inguinal lymphadenopathy
1st investigation
- anoscopy:
tumour visualised
Other investigations
- CT pelvis:
tumour visualised
Rectal ulcer
Rectal varices
History
painless rectal bleeding in a patient with history of portal hypertension
Exam
may reveal the stigmata of chronic liver cirrhosis such as jaundice, ascites, gynaecomastia, spider naevi, palmar erythema, finger clubbing
1st investigation
- colonoscopy:
vascular structures extending proximally from the dentate line
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Other investigations
Post-polypectomy bleeding
History
painless rectal bleeding after colonoscopy.
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); patients may be pale if anaemia is present, abdominal examination is non-contributory
1st investigation
- FBC:
haemoglobin usually normal; low in patients with severe blood loss
- platelets:
usually normal; may be thrombocytopenia
- clotting studies:
normal
- colonoscopy:
bleeding or stigmata of recent bleed from the site of the polypectomy
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Other investigations
Non-steroidal anti-inflammatory drug (NSAID) colopathy
History
painless rectal bleeding, history of use of NSAID medication
Exam
general examination is usually normal
1st investigation
- colonoscopy:
erosions and ulcerations in the colon may be seen
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Other investigations
Upper GI bleeding (rapid transport)
History
melaena and rectal bleeding, upper abdominal pain also may be present
Exam
vital signs may indicate severe bleeding (e.g., systolic BP <115 mmHg, heart rate >100 bpm); epigastric tenderness, orthostatic hypotension may be present, bleeding more likely to be severe
1st investigation
- FBC:
haemoglobin normal or low
- platelets:
usually normal
- clotting screen:
usually normal
- oesophagogastroduodenoscopy:
erosions, ulcerations or actively bleeding vessels may be seen
Other investigations
Prostate biopsy site bleeding
History
rectal bleeding at a few hours or days after a prostate biopsy
Exam
general examination is usually normal
1st investigation
- colonoscopy:
site of bleeding at the site of prostate biopsy
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Other investigations
Endometriosis
History
female sex, reproductive age, may be a history of dysmenorrhoea, pelvic pain, dyspareunia, infertility
Exam
lower abdomen tenderness; pelvic examination may reveal pelvic mass (ovarian endometrioma), fixed and retroverted uterus or uterosacral ligament nodularity and tenderness
1st investigation
- colonoscopy:
endometriotic lesions visualised
Other investigations
- transvaginal ultrasound:
ovarian endometrioma-homogeneous, low-level echoes; deep pelvic endometriosis such as uterosacral ligament involvement-hypoechoic linear thickening
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