Toxic Megacolon

Question 1

What is toxic megacolon?

Answer 1

Dilation of colon greater than 6cm occurs due to inflammation associated with ulcerative that causes thinning of colonic walls and deep ulcers.

There is acute transinflammation of colon with necrosis and granulation tissue filled with inflammatory cells

Question 2

How does toxic megacolon present?

Answer 2

Radiographic evidence of dilation greater than 6cm
And at least three of the following:
* Fever over 38 degrees C

* Heart rate greater than 120 beats/min

* Neutrophilic leukocytosis

* Anemia

Question 3

What is the presentation of toxic megacolon?

Answer 3

Patients with toxic megacolon present with severe abdominal pain, fever, chills, lethargy and abdominal distention and tachycardia.

Question 4

What will diagnostic tests show for toxic megacolon?

Answer 4

Diagnostic tests will show anaemia and leukocytosis, high inflammatory markers and severe diarrhoea and volume loss can lead to hypokalemia and hypoalbumnaemia

Question 5

What is a key sign on imaging for toxic megacolon?

Answer 5

CT scan will show Colonic wall thickening but there may be an accordion sign. Accordion sign is where the contrast appears trapped between the mucosal folds due to colonic wall thickening.

Question 6

What does target sign indicate?

Answer 6

Hyperaemia of mucosa, with excess vessels supplying the colon

Question 8

Whic imaging MUST be avoided in toxic megacolon?

Answer 8

Colonoscopy due to risk of perforation

Question 9

What is the initial management of toxic megacolon?

Answer 9

IV fluids
Antibiotics and replacement of electrolytes.
Correcting electrolyte disturbances like hypokalemia

-> If peritonitis is present, metronidazole or vancomycin should be used.