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ileosigmoid knotting ( isk ) is a rare cause of closed - loop intestinal obstruction , which rapidly progresses to gangrene of involved gut segments .
isk is a very unusual entity in western world , but is relatively common in asian , middle eastern and african nations .
although the reported mortality rate in isk varies from 0 to 48% ( mean 35.5% ) , but isk with gangrene has a mortality rate [ 1 , 3 ] of 20100% .
more than 330 cases in world and only 22 cases from india have been described so far in the literature as summarized in table  i. it is still a diagnostic dilemma for surgeons all over the world and only 028% cases could be diagnosed preoperatively .
x - ray abdomen can reveal large gas - filled loops of small and large bowels in the right mid and lower abdomen .
computed tomography ( ct ) is the best diagnostic modality in clinching the diagnosis . 

a 51-year - old male was brought in our casuality in shock with history of abdomen pain and non - passage of flatus and stools for 24 h. his blood pressure was 78/56 mmhg and pulse rate was 112 min .
abdomen was distended and tender . he was resuscitated , and x - ray of abdomen revealed multiple dilated gut loops as depicted in fig .  1 .
ileum was wrapped around sigmoid colon making two complete turns with gangrene of sigmoid colon and ileum as depicted in fig . 
clamps applied on large gut and sigmoid colon removed followed by ileum , and end jejunostomy was done in view of haemodynamic unstability of the patient along with descending sigmoid colon anastomosis .
the patient expired after 2 weeks despite exhaustive efforts due to complications of short bowl syndrome . 

figure  2:intraoperative picture showing ileal knotting around sigmoid colon resulting in gangrene of both .
the isk is rare but life - threatening type of closed - loop intestinal obstruction .
the exact mechanism of isk is still speculative . a long small bowel mesentery , long sigmoid mesocolon on a narrow pedicle and ingestion of high bulk diet after fasting are predisposing factors [ 1 , 6 ] .
the ileal loops can twist around sigmoid colon in clockwise ( 60.963.2% ) or anticlockwise direction ( 36.839.1% ) .
the knot is 360 in 52.9% , two 360 turns in 19.1% and three 360 turns in 5.9% cases .
isk is seen predominantly in males ( 80.2% ) , with a mean age of 40 years ( 490 years ) .
isk has been classified into four types as described in table  2 . in the present case
, we have type ia knot ( most common variety ) with two 360 turns of ileum over sigmoid colon .
atamanalp et al . in 2008 described a new classification of isk based on age , shock , associated chronic illness and shock as summarized in table  3 .
pain abdomen ( 100% ) , abdomen distension ( 94100% ) , nausea and vomiting ( 87100% ) and shock ( 060% ) are usually present at admission [ 1 , 2 , 9 ] . x - ray abdomen reveals a large gas - filled loop of sigmoid colon in the right mid and lower abdomen .
ct of abdomen can help to clinch the diagnosis in preoperative stage [ 1 , 2 ] .
it can markedly reveal a dilated loop of sigmoid colon with loss of haustration and non - enhancing thinned out wall . the characteristic whirl sign ( twisted mesentery and bowel )
convergence of superior mesenteric vein towards knot and medial pointing of caecum are other suggestive findings . despite availability of various modern diagnostic tools in the present era
2b18.920.65sigmoid colonileumclockwiseanticlockwise3type 31.5ileocaecal segmentsigmoid colon4type 4undetermined 
 table  3:new classification for isk c1c2ac2bc3ac3bc4ac4bc5c6a0d0one of a , d1two of a , d1at most 1 of a , d1two of a , d1at most 1 of a , d1two of a , d1s0s0s0s1s1s0s0s1g0g0g0g0g0g1g1g1g2c : class ; a ( age ) : a0 : under 60 years ; a1 : 60 years and older ; d ( associated disease ) : d0 : absent ; d1 : present ; s ( shock ) : s0 : absent ; s1 : present ; g ( bowel gangrene ) : g0 : absent ; g1 : present in the ileum or sigmoid colon ; g2 : in both segments . classification of isk [ 1 , 2 , 7 ] new classification for isk   c : class ; a ( age ) : a0 : under 60 years ; a1 : 60 years and older ; d ( associated disease ) : d0 : absent ; d1 : present ; s ( shock ) : s0 : absent ; s1 : present ; g ( bowel gangrene ) : g0 : absent ; g1 : present in the ileum or sigmoid colon ; g2 : in both segments .
exploratory laparotomy is the definite key to diagnose majority of these cases of diagnostic dilemma .
the incidence rate of gangrene was paradoxically high ( 90.9% ) in cases who presented within 24 h of onset of their symptoms than those presenting after 24 h of their symptoms   ( 57% ) as happened in the present case also .
excision of gangrenous segment with end - to - end anastomosis of healthy bowel is the most acceptable surgical procedure in the literature [ 1 , 2 ] .
a high index of suspicion is required for all these cases . in view of diagnostic dilemma and
rapidly fatal course of disease , urgent exploratory laparotomy is the best answer for better outcome . while selecting the type of surgery , general condition of patient
m.s . as the main and corresponding author certifies all authors that this paper is original and had not been sent to any other journal for publication .
wish to state that as in this case report , no research work is conducted so institutional ethical committee involvement was not done .
informed consent of the patient was taken , and he was acknowledged orally regarding the process and ensured that his identity will not be revealed anywhere .
ileosigmoid knotting ( isk ) is a rare cause of intestinal obstruction in which loops of ileum and sigmoid colon wrap around each other . 
 it is very uncommon in western world when compared with the african and asian region . 
 it is rapidly a progressive , fatal disease . 
 early diagnosis and intervention is the key of better outcome . 
 we are reporting a case of 51-year - old male who presented with shock within 24 h of onset of symptoms . 
 exploratory laparotomy revealed isk causing gangrene of ileum and sigmoid colon . in view of haemodynamic unstability , 
 end ileostomy was done after excising gangrenous segments . 
 the patient expired after 2 weeks due to complications of short bowl syndrome . 
 we are also tabulating all cases of isk reported in the literature till date .