Causes Of Toxic Megacolon: Symptoms, Diagnosis And Treatment

Toxic megacolon is a serious and life threatening condition of colon. It is characterized by abnormal dilatation of entire or part of colon (large intestine) accompanied with toxic symptoms. The dilatation is more than 6 cm. It can develop as a complication of inflammatory bowel disease or due to infection in colon.

The condition has great propensity to produce septic shock and marked dehydration.

Symptoms of toxic megacolon include bloody diarrhea, pain and distension of abdomen, fever, and several other symptoms of septic shock. Toxic megacolon is a serious condition and needs to be treated as an emergency. Treatment consists of medications, decompression of bowel, intravenous fluids. If the conservative measures fail, surgery may be necessary to remove the damaged segment of colon.

Causes And Risk Factors For Toxic Megacolon

The large intestine or colon is the last part of digestive system. The function of colon is to absorb water and remove the solid waste in the form of stool through anus.

Dilatation of colon is called megacolon. Dilatation is more than 6 cm. Toxicity is systemic spread of infection. Toxic megacolon is a serious condition that is mostly caused as a complication of irritable bowel disease, specifically ulcerative colitis and to lesser extent Crohn’s disease.

Inflammatory bowel disease (IBD) causes inflammation and irritation in the colon. IBD causes pain in abdomen and is chronic. In IBD, the colon expands, dilates and distends. Smooth muscle contraction of colon decreases and as a result there is accumulation of gas and feces in the colon. Eventually the layer of colon ruptures and the bacteria present in colon penetrate in the walls of large intestine causing systemic spread of infection.

Following risk factors are majorly responsible for toxic colon:

  • Ulcerative colitis
  • Crohn’s disease
  • Colon infection mainly caused by C. difficile bacteria. This bacterium can cause diarrhea to more severe condition such as toxic megacolon. However, other bacteria such as salmonella, shigella, and parasites such as entameba can also be responsible for toxic megacolon.
  • Reduced blood flow to colon.
  • Diabetes
  • Kidney failure
  • Suppressed immunity
  • Injury to the colon during instrumentation such as sigmoidoscopy, barium enema etc.

Signs And Symptoms Of Toxic Megacolon

The symptoms of toxic megacolon develop suddenly. There is rapid dilatation of the colon. As the colon enlarges in size it causes several symptoms such as:

  • Distention of abdomen
  • Pain in abdomen
  • Abdomen tenderness
  • Fever
  • Rapid heart rate
  • Low blood pressure
  • Feeble but fast pulse
  • Bloody diarrhea
  • Vomiting
  • Painful movement of bowels.
  • Urine output is decreased.
  • Increased rigidity of abdomen.
  • Rebound tenderness during examination of abdomen.
  • Confusion and disorientation due to toxicity.

Diagnosis And Treatment Of Toxic Megacolon

Diagnosis of toxic megacolon is made with the help of following:

  • Medical examination
  • Medical history
  • Ultrasonography
  • Physical examination of patient.
  • Blood tests such as complete blood count which shows increased number of total white blood cells and increased neutrophils. Blood sugar test is also done.
  • X-ray of abdomen shows abnormal gas and fluid levels.
  • CT scan of abdomen.

Toxic megacolon is rare but serious condition of large intestine. When present it is an emergency situation as there is high risk of mortality among untreated cases. Patient needs to be admitted in hospital.

Treatment consists of following:

  • Medicines: Intravenous administration of antibiotics to reduce infection and toxic megacolon. Various other medicines may be necessary as needed.
  • Giving rest to the bowel: Patient avoids eating and drinking for few hours or two days.
  • Decompression of bowel: This procedure helps to remove gas from the colon.
  • Intravenous fluids to maintain electrolyte balance and to prevent dehydration
  • Surgery is the last alternative when all the measures fail. During surgery a damaged segment of colon is removed.