The first job is not to find the cause. It is to work out how much blood has gone, how fast, and whether this patient is still bleeding now. The history does most of that, and it does it through the character of the blood and the state of the patient while they describe it.
What the blood itself tells you
| What the patient describes | Where it is from | What it means |
|---|---|---|
| Fresh red vomited blood, or clots | Upper GI, brisk | Active bleeding — treat as an emergency |
| Vomit like coffee grounds | Upper GI, slower | Blood altered by gastric acid; bleeding may have stopped |
| Black, tarry, offensive stool | Upper GI, usually | Melaena — digested blood, and at least several hundred millilitres of it |
| Fresh red blood on the paper or on the surface | Anorectal | Often benign, but never assumed to be |
| Dark red blood mixed through the stool | Colonic | Needs a colonoscopy, whatever the age |
The drug history patients do not think to mention
Ask by name, not by category. Patients do not consider these to be medicines:
- Aspirin — often taken for years and forgotten entirely
- NSAIDs bought over the counter for a bad back or a knee
- Anticoagulants — warfarin, and the direct oral anticoagulants
- Steroids, which also blunt the signs of a perforation
- Alcohol, asked about in units per week, not as a yes or no
The question that changes the diagnosis
In haematemesis, ask whether the vomiting began with food or without blood and became bloody only afterwards. Repeated retching that turns bloody after several non-bloody vomits suggests a Mallory–Weiss tear. Blood from the first vomit, in a patient with a history of liver disease or heavy alcohol use, raises varices, which are a different emergency with a different treatment.
In rectal bleeding, the questions that stop it being dismissed as haemorrhoids are weight loss, a change in bowel habit lasting more than six weeks, blood mixed through the stool rather than on it, a family history of bowel cancer, and iron deficiency anaemia. Any of those buys a colonoscopy.
Surgical pearl
Young patients compensate until they do not. A normal blood pressure in a 25-year-old who has vomited blood twice is reassurance you have not earned — look at the pulse, the postural drop and the peripheries instead.
Clerk a patient who is bleeding
The drug and alcohol history that decides between a tear, an ulcer and varices.Case 3 · clerk this patientRectal bleedingMargaret Lowry, 68, retired teacher
What separates haemorrhoids from something that needs a colonoscopy.
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