The initial phase of Crohn’s disease with colon involvement usually exhibits an inflammatory phenotype in which the fundamental lesions are ulcers of various sizes, some superficial and others with more notorious features, with geometric margins and increased depth (punch-out type ulcers). In some cases the lesions are confluent between preserved tissue zones, giving rise to a typical cobblestone appearance.
Transmural involvement of the lesions gives rise to narrowing of the lumen secondary to thickening of the wall. Segmental involvement and the patched distribution of the lesions are typical features of Crohn’s disease (CD).
Figure 1: Segmental, patched involvement typical of CD. Ulcers with geometrical margins and variable depth alternating with areas of preserved tissue. At transverse colon level, confluence of the ulcers gives rise to annular ulcerated stricturing.
Figure 2: The same patient may present ulcers of different sizes and morphology, as in this case where initially aphthoid and small ulcers are seen together with larger ulcers exhibiting irregular margins.
Perianal disease is more common in cases of colonic localization of CD, with maximum expression in those cases where the rectum is affected (80-92% according to different studies). Although the precise mechanism underlying the formation of fistulas is not known, one possibility is that they may form from penetrating ulcers in the anorectal region.
Figure 3. Patient with severe perianal disease. Rectal CD involvement is seen, presenting a deep and penetrating ulcer in the anal canal, with spontaneous purulent drainage.
The study was completed by pelvic MRI for adequate assessment of the internal fistular trajectory.
The severity of the endoscopic lesions in CD is correlated to a poorer evolutive prognosis and an increased incidence of surgery. The information obtained from ileocolonoscopy therefore can help us to decide the management approach best suited to each individual case.
Figure 5. Initial manifestation of CD with a severe outbreak refractory to corticosteroid treatment. Extensive endoscopic involvement with deep confluent ulcers exhibiting irregular margins. Cobblestone appearance with inflammatory thickening of the wall and narrowing of the lumen. Given the clinical-endoscopic severity of the case, induction treatment with anti-TNF drugs was started, followed by a good response.
In some cases the clinical manifestations are determined by other factors (infections, drugs etc.) – ileocolonoscopy being useful for the differential diagnosis and for deciding adequate treatment.
Figure 6. Patient with CD subjected to maintenance therapy with azathioprine and in remission for over two years. The patient reported with sudden onset diarrhea and abdominal discomfort. Colonoscopy revealed mucosal involvement in the cecal region with edema, point erosions and exudate. Biopsy revealed oxyuria infestation. The patient was treated with mebendazole, followed by remission of the symptoms.
Although in clinical practice endoscopic monitoring of the disease with the purpose of assessing mucosal healing has not been systematically applied, mucosal healing is correlated to a better course of the disease, with a prolongation of clinical remission and a reduction in complications and in the need for surgery.
Figure 7. Serious and extensive involvement. Healing of ulcerative lesions – the video showing residual lesions or lesions in the process of healing.
The frequency of strictures in CD depends on the location of the disease, and up to 21% of patients with ileal involvement present strictures. Between 4-10% of all cases of CD present colic strictures, and 8% of the cases are complicated by anorectal strictures. It is important to differentiate between predominantly inflammatory or fibrotic strictures, since the management approach depends on this distinction.
Figure 8. Patient with CD subjected to maintenance treatment with azathioprine. Clinically stable, though with sustained C-reactive protein elevation as reflected by the control laboratory tests. Colonoscopy revealed a normal mucosa up to the distal transverse colon, where a stricture not passable with the endoscope was found. Nodular lesions with a cobblestone-like appearance were seen, together with superficial ulcerations adjacent to the stricture zone. Transmural thickening and en bloc sweeping of the entire zone upon obtaining biopsies. ((Clinical case 3)
In the presence of stricture in a patient with CD, particularly in cases of long-standing colon disease, correct assessment of the stricture over its entire length is required. If the stricture cannot be passed, a fine endoscope can be used, collecting biopsies over the entire trajectory. It should be remembered that the presence of stenosis as well as of pseudopolyps and sustained inflammation in a patient with inflammatory bowel disease is associated with an increased risk of developing colorectal cancer.
Figure 9. Long-evolving CD. Patient with ulcerated anorectal stricture passable with the gastroscope. At a distance of 15 cm, within the distal rectum, a non-passable ulcerated stricture is observed.
Figure 10. The same case evaluated with a pediatric gastroscope, passing the stricture with difficulty. This was a short and ulcerated stricture with angulations along its axis that could complicate the option of endoscopic dilatation. Numerous biopsies were taken from the zone for histological study. After passing the stricture another short and annular stricture was observed. This was easily passed, reaching the cecum at a distance of 50 cm (rectified and short colon associated to long-evolving disease). Due to its annular, short and straight characteristics, the stricture seen in the vicinity of the hepatic angle would be more suitable for endoscopic dilatation.
Figure 11. Patient with long-evolving CD. Control colonoscopy revealed left colon pseudopolyps in relation to previous inflammation. A stricturing lesion of infiltrating appearance was observed at the hepatic angle, precluding passage of the endoscope. Histological findings: Signet ring cell adenocarcinoma.
The development of abscesses and fistulas between loops or adjacent organs characterizes the penetrating phenotype of the disease. The approach in the presence of entero-enteric fistulas depends on their location and on the associated symptoms. In this sense, and depending on the case, the choices comprise medical management with biological agents, or surgery.
Figure 12. Long-evolving CD with severe clinical worsening. Colonoscopy: two luminal spaces were noted in the sigmoid region, one of which showed important inflammation. Exploration continued along what appeared to be the “normal” lumen, reaching the cecal zone where important disease involvement was again noted. In the cecal region a large fistular orifice was observed, through which the extremity of the endoscope was visualized, probably located in the sigmoid colon at the point of the initial double luminal space. An opaque enema revealed a large-caliber colon-sigmoid fistula; surgery was therefore decided.