Toxic megacolon: symptoms, causes and emergency treatment

The word megacolon means an abnormally enlarged colon. In toxic megacolon the enlargement happens suddenly, in the setting of severe inflammation of the bowel. Crohn’s & Colitis UK describes it as a complication of ulcerative colitis in which, when inflammation is extensive and severe, the bowel wall thins and the colon becomes bloated with gas.

It is rare. The charity describes bowel complications of colitis as occurring in very rare cases. The NHS says ulcerative colitis is rarely life-threatening, but that if you have a severe flare-up you may need emergency treatment in hospital, and that you may also need emergency surgery if you have a very bad flare-up.

Toxic megacolon is therefore best understood as one end of the severe spectrum of colitis. It is a surgical and medical emergency in which the thinned bowel wall is at risk of splitting, which is why early recognition matters so much.

Severe colitis already causes frequent bloody diarrhoea and tummy pain. Crohn’s & Colitis UK describes acute severe ulcerative colitis as a serious medical emergency that needs a stay in hospital for treatment and monitoring, with signs that the body is being significantly affected, such as fever or an increased heart rate.

For toxic megacolon specifically the charity lists a high fever with pain and tenderness in the tummy. Signs of perforation, which it says is very rare but very serious, include severe tummy pain that is present all the time, high fever, and feeling sick and being sick.

The NHS list of urgent warning signs for a severe ulcerative colitis flare-up also includes a fast heartbeat and not being able to fart or poo.

• A high fever, or feeling hot, cold and shivery.

• Severe tummy pain that is constant, with tenderness.

• A fast heartbeat.

• Feeling sick and being sick.

• Not being able to fart or poo (NHS list for a severe flare-up).

The sources used here describe toxic megacolon as arising from extensive, severe inflammation, in the context of ulcerative colitis. The NHS explains that ulcerative colitis is a condition in which parts of the large bowel and rectum become inflamed, that it is one of a group of conditions called inflammatory bowel disease, and that it is thought to be an autoimmune condition.

The NHS lists the flare-up triggers as stress, infections, changes in medicines, taking NSAIDs such as ibuprofen or aspirin, and certain foods, although sometimes there is no obvious trigger. It advises not taking NSAIDs unless prescribed by a doctor. People whose colitis is poorly controlled are therefore the ones to be most alert to the warning signs below.

The sources used here do not set out a detailed treatment protocol, so only the general picture can be described. Crohn’s & Colitis UK says it is essential to get treatment quickly and that emergency surgery may be needed. It describes acute severe ulcerative colitis as needing a stay in hospital for treatment and monitoring.

The NHS describes colectomy, an operation to remove part or all of the large bowel, as an option for ulcerative colitis and says emergency surgery may be needed if you have a very bad flare-up. Surgery involves either an ileostomy, where the small bowel is connected to a hole in the tummy and poo is collected in a bag, or an ileo-anal pouch, where an internal pouch is made from small bowel and connected to the bottom. Your care team discusses the benefits and risks with you.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have symptoms of ulcerative colitis and very bad or bloody diarrhoea, a high temperature or feeling hot, cold or shivery, a fast heartbeat, you cannot fart or poo, or you are worried. If you have already been diagnosed and are having a severe flare-up you can also contact your care team.

It says to call 999 or go to A&E if you have severe tummy pain, if you are bleeding non-stop from your bottom, if there is a lot of blood or large clots when you poo, or if you are vomiting blood or poo, or your sick looks like coffee grounds or soil. It says not to drive to A&E, but to ask someone to drive you or call 999, and to bring your medicines.

Good control of ulcerative colitis is the best protection. The NHS advises taking prescribed medicines even when you feel well, attending regular check-ups so that treatment and complications can be monitored, and contacting your care team early when symptoms change. It advises avoiding NSAIDs unless prescribed and drinking plenty of fluids if you have diarrhoea.

Crohn’s & Colitis UK suggests that people with colitis know how to contact their IBD team quickly, and that includes having a direct number or advice line. It is better to call early with a worsening flare-up than to wait until the symptoms become severe.

Outcomes depend on how quickly the problem is recognised and treated, and on the individual’s overall health. The sources used here do not give outcome figures, and general information should not be read as a prediction for your own situation.

People who have had emergency surgery may need time to adjust, particularly if they have a stoma. The NHS notes that support is available, including from Crohn’s & Colitis UK and the Ileostomy and Internal Pouch Association.

Suspected toxic megacolon is an emergency, so it is dealt with through NHS 111, 999 or A&E rather than a routine appointment. The NHS says that if you already have a diagnosis of ulcerative colitis and are having a severe flare-up you can also contact your care team.

Routine colitis care is usually led by a gastroenterologist and an IBD nurse. Private gastroenterology review is available for ongoing management, but an emergency should never wait for a private appointment.