Volvulus
| Sigmoid volvulus | Caecal volvulus | |
|---|---|---|
| Patient | elderly, chronic constipation, institutionalised, neuropsychiatric; "volvulus belt" (Africa, India, South America): younger patients on high‑fibre diets | younger, mobile caecum, previous surgery |
| AXR | huge inverted‑U loop arising from the pelvis toward the RUQ, apex under the left hemidiaphragm, absent haustra: coffee bean sign, bent inner tube / omega loop, Frimann‑Dahl sign (three dense lines converging toward the pelvis), northern exposure sign (apex above the transverse colon), liver overlap sign | dilated caecum displaced to the LUQ/mid‑abdomen: comma / embryo / kidney‑bean shape, small bowel dilated |
| CT | whirl sign (twisted mesentery), bird's beak at the torsion point, X‑marks‑the‑spot | whirl sign, beak |
| Contrast enema | bird's beak / ace of spades tapering at the twist | beak at the caecum |
| Management | endoscopic decompression (rectal tube/sigmoidoscopy) then elective sigmoidectomy; surgery if ischaemic | surgery (right hemicolectomy) |