Advances in the diagnosis and management of toxic megacolon (Part 2)
To diagnose TM, the physician must rely on a combination of clinical criteria and radiographical evidence of dilation, as described by Jalan et al in 1969 . Gan and Beck outline the limited data to support the use of CT or other techniques for the diagnosis of TM. We discovered an article, written since their review was published, that examined the utility of ultrasound as a primary diagnostic tool in a small number of patients with TM . The limited use of radiographical techniques may be due to our incomplete understanding of the pathophysiology of this disease.
The relationship between clinical disease activity and radiologically visible intestinal inflammation is poorly defined, thus limiting the present utility of ultrasonography and CT in diagnosis. We agree with the authors of this review, however, that CT is the best means of identifying septic complications and perforation and, thus, should be used early in cases of TM. We also concur that direct visualization of the colon using endoscopy has no place unless the etiology of the disease is unknown (eg, IBD versus infectious). Under those circumstances, a limited sigmoidoscopy may be performed, with minimal insufflation. Lastly, Gan and Beck also drew our attention to the lack of clinical, radiographical or laboratory parameters that are useful in determining the prognosis.