Rectal bleeding usually indicates lower GI bleeding (below duodenojejunal junction). Bear in mind that any patient, aged >45 yrs old, with complaints of :
colickly abdominal pain, PR bleeding and changes in bowel habits
Colorectal CA must be considered unless proven otherwise.
Some causes of rectal bleeding
1) Anal cause
Piles are very common.
Uncomplicated piles are not painful.
Fissure-in-ano usually causes painful defecation.
The precipitating cause is usually constipation, hence constipation is usually worsened by the patient fear of passing motion, since it's painful.
Pain usually persists for minutes or even hours after defecation.
The history of anal carcinoma is similar to that of Fissure-in-ano.
However, it's usually seen in the elderly.
History of penetrating injury into the anus.
Sexual abuse? Anal intercourse?
2) Colorectal causes
As mentioned in previous posts
The history given by patient is usually the same as carcinoma
The difference between Diverticulitis and Carcinoma :
Duration : Diverticulitis = longer, Carcinoma = shorter
Pain : Diverticulitis = usually painful, Carcinoma = painless (initial)
Bleeding pattern : Diverticulitis = periodic, massive
Carcinoma = usually smaller in amount, persistent
Mass per abdomen : Diverticulitis = tender, Carcinoma = tenderless
Abdominal radiograph : Diverticulitis = diffuse changes, Carcinoma = localised
d) Inflammatory bowel disease
Usually presented as sudden onset of watery diarrhoea, together with brown stools, mucous, and blood. Ulcerative proctitis can presents as tenesmus
e) Ischaemic colitis, angiodysplasia
f) Irradiative colitis
Especially common in patients with pelvic malignancies, due to irradiation
g) Rectal prolapse
Patient usually complaints of something hanging out at his/her back opening besides PR bleeding
3) Small bowel
a) Meckel's diverticulum
Consider this diagnosis in young adults with frequent painless PR bleeding
b) Acute mesenteric infarction
Patient with h/o of cardiac disease (embolism), with complaints of diffuse abdominal pain, PR bleeding, collapse, with signs of shock, etc -> consider this as well
4) Massive Upper GI bleeding
Due to the massive nature of the upper GI bleeding, the intestinal transit is fast, and hence instead of presenting with hematemesis, patient presents with massive PR bleeding, with shock-like features
5) Bleeding disorders
6) Drugs (anticoagulants)
7) Uremic bleeding
8) Infective causes - dysentry