Aims:
Ileo-colonoscopy is the procedure of choice for chronic non-bloody diarrhea (CNBD)
of unknown origin. The histological evaluation at different colonic sites is mandatory
to assess the presence of microscopic colitis. However, the value of routine ileal
biopsy on normal-appearing mucosa as assessed with standard-resolution white-light
ileoscopy is controversial given its reported low diagnostic yield. Hence, we have
assessed for the first time the accuracy of retrograde ileoscopy using high-definition
and dye-less chromo-endoscopy (HD+DLC), thereby calculating the impact and cost of
routine ileal biopsy in CNBD.
Tab. 1:
Statistical measures of the performance of retrograde ileoscopy with HD plus virtual
chromo-endoscopy using histopathology as the gold standard
|
Test
|
Value
|
|
Sensitivity
|
0.933 (0.660 – 0.996)
|
|
Specificity
|
0.983 (0.966 – 0.992)
|
|
Positive Likelihood ratio
|
55.6 (27.6 – 112.1)
|
|
Negative Likelihood ratio
|
0.068 (0.010 – 0.450)
|
Methods:
Patients with CNBD of unknown origin were prospectively enrolled for ileo-colonoscopy
with HD+DLC in 5 referral centers. Multiple biopsies were systematically performed
in each colo-rectal segment and terminal ileum for histo-pathological analysis.
Results:
Between 2014 and 2017, 546 consecutive patients were recruited. Retrograde ileoscopy
success rate was 97.6%. 492 patients (mean age: 53 ± 18 years) fulfilled all the inclusion
criteria: following endoscopic and histo-pathological work-up, 7% had lymphoid nodular
hyperplasia and 3% had isolated ileitis. Compared to the histo-pathology as the gold
standard, retrograde ileoscopy with HD+DLC showed 93% sensitivity, 98% specificity
and 99.8% negative predictive value. In patients with normal ileo-colonoscopy, ileum
histology had no diagnostic gain and came with a US$ 26.5 cost per patient.
Conclusions:
Retrograde ileoscopy with HD+DLC predicts the presence of ileitis in CNBD with excellent
performance. The histo-pathological evaluation of the terminal ileum is the gold standard
for the diagnostic assessment of visible lesions but has no added diagnostic value
in CNBD patients with negative ileo-colonoscopy inspection using modern endoscopic
imaging techniques.
