We report a case of a 21 year old lady who presented with features of toxic megacolon diagnosed as a case of ulcerative colitis. She developed mild pancreatitis following 6 days of starting mesacol (mesalamine) therapy. The cause of the pancreatitis may have been due to mesalamine or is it an extraintestinal manifestation of ulcerative colitis.

Introduction
Toxic megacolon is an acute toxic colitis characterised by total or segmental non obstructive colonic dilatation of atleast 6 cm with systemic toxicity. Ulcerative colitis is a cause which is often overlooked in our country as amoebiasis is often clinically diagnosed and treated. It is a gastrointestinal emergency requiring prompt management to avoid fatal outcome. This article is documented for increasing the awareness of this GI emergency and the occasional occurrence of pancreatitis associated with such cases.

Case Report
A 21 years old lady presented with history of loose stools of 1 and ½ month duration associated with passage of blood and mucus. She had been treated elsewhere with anti amoebic agents and other anti diarrhoea medication. She had lower abdominal pain and weight loss. On examination she was dehydrated, toxic, febrile: 101.8oF, pulse rate: 120/min. Her blood pressure: 90/60 mmHg. Her lab parameters showed anaemia, leucocytosis, hypokalaemia and hypoproteinaemia. Abdominal radiograph showed dilatation of the transverse and pelvic colon with a maximum diameter of 6 cm (Figs. 1 and 2). She had features of toxic megacolon. Ultrasound abdomen revealed that liver, pancreas were normal, mild thickening of caecum was noted with no free fluid. Sigmoidoscopy revealed moderate colitis and no ulceration seen. Biopsy from sigmoid and rectum showed a picture of erosions and ulceration of the mucosa and submucosa. Formation of crypt abscess suggestive of ulcerative colitis. A double contrast barium enema was not done in view of risk of perforation.

The clinical severity of ulcerative colitis was graded as severe to fulminant disease according to criteria of TRUE LOVE and WITTS. She was treated with bowel rest, fluid and electrolyte imbalance corrected, antibiotics, steroids, aminoacids, blood transfusion. She was started on mesalamine. 6 days after starting the drug the patient had developed upper abdominal pain. Her serum amylase mildly elevated to 553 u/l. Repeat USG reported as pancreas mildly swollen, with a cystic area in relation with the tail of pancreas measuring about 4.3 x 2.4 cm. She was treated conservatively for the mild pancreatits. In about 2 days her abdominal pain subsided, clinical condition improved and was discharged. At follow up for 6 months she continued to be well.

Figs. 1 and 2 : Abdominal X-rays show dilatation of transverse and pelvic colon, maximum diameter of 6 cm.

Discussion
Toxic megacolon accounts for 5% of severe attacks of ulcerative colitis and common in the western world. Among the diagnostic criteria the first criterion is radiographic evidence of colonic dilatation of atleast more than 5.5 cm, the second criteria is any three of the following fever more than 101.5oF, tachycardia more than 120, leucocytosis more than 10,000 and anaemia and the third criteria is any one of the following-dehydration, altered mental status, electrolyte imbalance or hypotension. Among various causes of toxic megacolon ulcerative colitis is the commonest. The management of toxic megacolon requires aggressive medical therapy.

The main goal is to treat toxaemia, correct fluid and electrolyte disturbances, reduce colonic distension and prevent perforation. Careful monitoring of complete haemogram, electrolytes, abdominal radiograph every 6-12 hours is essential. Emergency surgery is considered in case of deterioration. Mortality associated with surgery prior to onset of perforation is less (2-8%) than that with operating for colonic perforation more than 40%.

There are non surgical alternatives also like colonic decompression, hyperbaric oxygen, cyclosporine, infliximab, anti tumour necrosis factor, heparin, interferon beta 1, epidermal growth factor, rcp-58 and DHEA, that have been used to treat toxic megacolon.

Majority of patients respond to conservative treatment as was in our case. She developed mild pancreatitis. It has been known that following mesalamine therapy patients develop acute pancreatitis. It is usually observed in the first week to first month of use. There have been reports occurring even after 2 days of therapy. Mesalamine induced pancreatitis though rare are known to occur. It is of an idiosyncratic nature either due to hypersensitivity or free oxygen radicals. The clinical course is essentially benign in most of the cases. In our case also, the patient developed mild pancreatitis after 1 week of starting mesalamine therapy, mesalamine was continued under careful observation, her symptoms settled down within a day. The mild pancreatitis was probably an extra colonic manifestation of ulcerative colitis.

In conclusion early detection and prompt institution of medical therapy are critical in the management of toxic megacolon. Acute pancreatitis must be considered when an occurrence of increasing upper abdominal pain occurs during such therapy and appropriate tests and management is warranted.

References

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