A 80 year old lady is admitted with abdominal distension and difficulty breathing. She is found to have ascites secondary to an ovarian malignancy.
Her ascites are drained. One day later her pain is much improved although she is constipated, so her opiods are stopped. She is started on macrogol (one sachet twice a day). Three days later senna (15mg at night) is added. Five days later she still complains of persistent constipation.
She is drinking about 1 litre a day and is generally immobile. She passes hard small stools every two to three days. She denies straining or PR blood. Her rectum is loaded with impacted faeces. Manual evacuation of the faeces removes three golf ball sized impacted faeces. The next day she passes only small watery stool.
You are called to review her. What is the most appropriate treatment for her constipation?
Impacted stool on PR with symptoms suggestive of overflow diarrhoea mean that this patient is likely to have impacted faeces.
This changes management quite a bit from constipation without impacted faeces.
One approach is to first soften the stools, then try pushing them out with stimulants, and then use enemas if all this fails.
If stools are hard, use a high dose of an oral macrogol.
Use a stimulant laxative if stools are already soft, or after a few days of high dose macrogol.
Arachis oil at night (stool softener/lubricant) or sodium citrate (osmotic) enema.
Arachis oil is given warmed and softens the stools overnight. Sodium citrate should produce a bowel movement within 5-15 minutes.
Arachnis oil at night and citrate enema the next morning. Consider sodium phosphate instead of citrate if large volume. However sodium phosphate comes with risks including rectal gangrene in people with haemorrhoids.
Repeat if needed. You may need to resort to manual evacuation. Get help from an impactologist rather than prescribing enemas in the long term.