Elderly farmer with gross abdominal distension and absolute constipation
A 58-year-old farmer presents to a zonal hospital with four days of abdominal distension, absolute constipation, and vomiting. He reports two similar episodes in the past year that resolved after passing a large amount of flatus and stool. He has chronic constipation and takes no regular medicines. On examination the abdomen is grossly distended and tympanitic, with mild generalized tenderness but no guarding or rebound. Pulse 104/min, BP 112/70 mmHg, temperature 37.8°C, respiratory rate 22/min. Digital rectal examination shows an empty rectum. Plain abdominal radiograph shows a massively dilated loop arising from the pelvis, with a coffee-bean appearance and no free air. There is no CT scanner. White cell count is 13,200/µL.
1. What is the most likely diagnosis and why? Explain how you would argue against perforation and against a malignant obstruction at this stage.
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Most likely diagnosis: sigmoid volvulus. The combination of an elderly patient with chronic constipation, recurrent self-limiting episodes, gross tympanitic distension, absolute constipation, and a plain radiograph showing a massively dilated pelvic loop with a coffee-bean sign is classic. The empty rectum supports large-bowel obstruction rather than faecal impaction.
Why not perforation? There is no guarding or rebound, no free air under the diaphragm, and the patient is not shocked; pulse 104/min and temperature 37.8°C are concerning but not diagnostic of perforation. The white cell count is only mildly raised. A plain film cannot exclude early ischaemia, so repeated clinical assessment is essential.
The main differential is a distal colorectal cancer causing obstruction. Recurrent identical episodes that resolve spontaneously favour volvulus, but malignancy can coexist. The absence of CT should not delay decompression, but it does mean that the response to sigmoidoscopy and the presence of blood or ischaemic mucosa become critical decision points.
2. Describe your initial non-operative management and the criteria that would make you stop and proceed to surgery.
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Resuscitate with intravenous fluids, keep the patient nil by mouth, insert a nasogastric tube, correct electrolytes, give analgesia, and monitor urine output. If there is no peritonitis, no systemic toxicity, and no free air, proceed to flexible sigmoidoscopy and attempt detorsion. Insufflate air gently, pass a flatus tube beyond the twist, and leave it in place to decompress. Successful detorsion is confirmed by a rush of flatus and stool and by improvement in distension.
Criteria to stop and operate: frank blood or dusky, ischaemic mucosa at endoscopy; inability to pass the scope beyond the obstruction; clinical deterioration; peritonitis; or signs of perforation. Do not persist with endoscopic attempts if the mucosa looks non-viable. After successful detorsion, the patient remains at high risk of recurrence, so prepare for definitive surgery during the same admission once the bowel is decompressed and the patient is optimised.
3. What definitive operation would you plan after successful decompression, and what intraoperative finding would change your plan?
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Definitive treatment is sigmoid colectomy with primary anastomosis after mechanical bowel preparation and correction of dehydration, performed during the same admission because recurrence after detorsion is high - often quoted above 50%. If the patient is frail or the bowel is unprepared, a staged approach may be safer.
What changes the plan: at laparotomy, if the sigmoid is gangrenous or perforated, resect the dead bowel and bring out a colostomy (Hartmann procedure) rather than anastomose unprepared, contaminated bowel. If a sigmoid cancer is found, follow oncological principles and resect with adequate margins. If the entire colon is dilated, consider Ogilvie syndrome or a distal obstruction and avoid unnecessary resection. Postoperative care includes monitoring for recurrence, early ambulation, and treating constipation.