Palliative medicine and end of life care for MRCP Part 1

A 68-year-old man with metastatic cancer is started on morphine for pain. A week later he has hard, infrequent stools and abdominal discomfort. He has no bleeding or weight change beyond his illness. What is the most likely diagnosis?

1. Hypothyroidism Constipation with tiredness, feeling the cold more than usual, and weight gain, from an underactive thyroid. It does not fit hard, infrequent stools that begin soon after starting a strong opioid.
2. Neurogenic bowel Constipation caused by disease of the spinal cord or of the autonomic nerves (the nerves that run the body's automatic functions). But hard, infrequent stools that begin soon after starting a strong opioid does not point to it.
3. Hypercalcaemia Constipation with thirst, confusion and a raised blood calcium level. Here, hard, infrequent stools that begin soon after starting a strong opioid points elsewhere.
4. Irritable bowel syndrome with constipation Long-standing bowel symptoms with no alarm features. That does not match hard, infrequent stools that begin soon after starting a strong opioid.
5. Opioid-induced constipation correct Correct. Hard, infrequent stools soon after starting morphine (a strong opioid) are opioid-induced constipation.

The point: Constipation means passing stools less often than normal, or with difficulty, and it is a common and often distressing problem in palliative and geriatric care. It helps to split it into primary (functional) constipation, where no clear cause is found, and secondary constipation, where something specific is driving it. The causes worth remembering are drugs (opioids most of all, but also anticholinergic drugs, iron tablets, calcium-channel blockers and antacids), metabolic problems (hypothyroidism, an underactive thyroid; hypercalcaemia, a raised blood calcium; hypokalaemia, a low blood potassium), a mechanical blockage in the bowel, and nerve disease. In palliative care, almost every patient on a strong opioid becomes constipated, because opioids slow the gut down. Unlike most other opioid side effects, the body never builds up tolerance to this one, so a stimulant laxative (usually together with an osmotic laxative, which pulls water into the bowel) is started at the same time as any strong opioid, rather than waiting for constipation to appear. The key safety step with a new case, especially in an older patient, is to check for the red flags of colorectal cancer: a lasting change in bowel habit, rectal bleeding, weight loss and iron-deficiency anaemia (anaemia from low iron stores). Any of these need proper investigation. Faecal impaction (a hard mass of stool stuck in the rectum) can cause overflow diarrhoea, liquid stool leaking past the blockage, which is easily mistaken for ordinary diarrhoea. Treatment combines basic steps, fluids, fibre and staying mobile, with laxatives matched to how they work: bulk-forming (ispaghula, which adds bulk to the stool), osmotic (macrogol or lactulose, which pull water into the bowel) and stimulant (senna or bisacodyl, which make the bowel contract), plus suppositories or enemas for impaction. The exam themes are opioid-induced constipation and its preventive laxative, the red flags that lead to cancer investigation, and matching the laxative type to the problem.

Source: BNF — constipation treatment summary British National Formulary · tier 3, national formulary

A 68-year-old man with metastatic cancer is started on morphine for pain. A week later he has hard, infrequent stools and abdominal discomfort. He has no bleeding or weight change beyond his illness. What is the most appropriate investigation?

1. Check calcium, thyroid function and potassium These metabolic causes can be put right once they are found. That does not match hard, infrequent stools that begin soon after starting a strong opioid.
2. Imaging if bowel obstruction is suspected This confirms or rules out a blockage. But hard, infrequent stools that begin soon after starting a strong opioid does not point to it.
3. A history of stool frequency, consistency and drugs This shows how the bowel is behaving and what may be causing it. It does not fit hard, infrequent stools that begin soon after starting a strong opioid.
4. Screen for red flags of colorectal cancer Bleeding, weight loss and anaemia change what happens next. Here, hard, infrequent stools that begin soon after starting a strong opioid points elsewhere.
5. Review the opioid and other constipating drugs correct Correct. The opioid is the cause here, and it can be treated.

The point: Constipation means passing stools less often than normal, or with difficulty, and it is a common and often distressing problem in palliative and geriatric care. It helps to split it into primary (functional) constipation, where no clear cause is found, and secondary constipation, where something specific is driving it. The causes worth remembering are drugs (opioids most of all, but also anticholinergic drugs, iron tablets, calcium-channel blockers and antacids), metabolic problems (hypothyroidism, an underactive thyroid; hypercalcaemia, a raised blood calcium; hypokalaemia, a low blood potassium), a mechanical blockage in the bowel, and nerve disease. In palliative care, almost every patient on a strong opioid becomes constipated, because opioids slow the gut down. Unlike most other opioid side effects, the body never builds up tolerance to this one, so a stimulant laxative (usually together with an osmotic laxative, which pulls water into the bowel) is started at the same time as any strong opioid, rather than waiting for constipation to appear. The key safety step with a new case, especially in an older patient, is to check for the red flags of colorectal cancer: a lasting change in bowel habit, rectal bleeding, weight loss and iron-deficiency anaemia (anaemia from low iron stores). Any of these need proper investigation. Faecal impaction (a hard mass of stool stuck in the rectum) can cause overflow diarrhoea, liquid stool leaking past the blockage, which is easily mistaken for ordinary diarrhoea. Treatment combines basic steps, fluids, fibre and staying mobile, with laxatives matched to how they work: bulk-forming (ispaghula, which adds bulk to the stool), osmotic (macrogol or lactulose, which pull water into the bowel) and stimulant (senna or bisacodyl, which make the bowel contract), plus suppositories or enemas for impaction. The exam themes are opioid-induced constipation and its preventive laxative, the red flags that lead to cancer investigation, and matching the laxative type to the problem.

Source: BNF — constipation treatment summary British National Formulary · tier 3, national formulary

A 68-year-old man with metastatic cancer is started on morphine for pain. A week later he has hard, infrequent stools and abdominal discomfort. He has no bleeding or weight change beyond his illness. What is the most appropriate management?

1. Investigate red flags for colorectal cancer This rules out a dangerous underlying cause. That does not match hard, infrequent stools that begin soon after starting a strong opioid.
2. Rectal measures for faecal impaction Suppositories or enemas clear a blockage of hard stool. Here, hard, infrequent stools that begin soon after starting a strong opioid points elsewhere.
3. Treat a reversible metabolic cause Correcting the calcium or the thyroid level fixes the constipation. It does not fit hard, infrequent stools that begin soon after starting a strong opioid.
4. Co-prescribe a stimulant laxative when starting a strong opioid correct Correct. A stimulant laxative is given alongside because the body never gets used to opioid-induced constipation, so it will not settle by itself.
5. Combine a stimulant with an osmotic laxative One laxative gets the bowel moving and the other softens the stool, so together they work better. But hard, infrequent stools that begin soon after starting a strong opioid does not point to it.

The point: Constipation means passing stools less often than normal, or with difficulty, and it is a common and often distressing problem in palliative and geriatric care. It helps to split it into primary (functional) constipation, where no clear cause is found, and secondary constipation, where something specific is driving it. The causes worth remembering are drugs (opioids most of all, but also anticholinergic drugs, iron tablets, calcium-channel blockers and antacids), metabolic problems (hypothyroidism, an underactive thyroid; hypercalcaemia, a raised blood calcium; hypokalaemia, a low blood potassium), a mechanical blockage in the bowel, and nerve disease. In palliative care, almost every patient on a strong opioid becomes constipated, because opioids slow the gut down. Unlike most other opioid side effects, the body never builds up tolerance to this one, so a stimulant laxative (usually together with an osmotic laxative, which pulls water into the bowel) is started at the same time as any strong opioid, rather than waiting for constipation to appear. The key safety step with a new case, especially in an older patient, is to check for the red flags of colorectal cancer: a lasting change in bowel habit, rectal bleeding, weight loss and iron-deficiency anaemia (anaemia from low iron stores). Any of these need proper investigation. Faecal impaction (a hard mass of stool stuck in the rectum) can cause overflow diarrhoea, liquid stool leaking past the blockage, which is easily mistaken for ordinary diarrhoea. Treatment combines basic steps, fluids, fibre and staying mobile, with laxatives matched to how they work: bulk-forming (ispaghula, which adds bulk to the stool), osmotic (macrogol or lactulose, which pull water into the bowel) and stimulant (senna or bisacodyl, which make the bowel contract), plus suppositories or enemas for impaction. The exam themes are opioid-induced constipation and its preventive laxative, the red flags that lead to cancer investigation, and matching the laxative type to the problem.

Source: BNF — constipation treatment summary British National Formulary · tier 3, national formulary