A plain abdominal X-ray in a patient with a sigmoid volvulus will show a distended bowel loop with its apex in (AIIMS Nov 2011)
|A||Right iliac fossa|
|B||Left iliac fossa|
Sigmoid volvulus may present as acute or subacute intestinal obstruction
a. There is usually a sudden onset of severe abdominal pain, vomiting, and obstipation.
b. The abdomen is usually markedly distended and tympanitic.
c. There is always the possibility that the condition can be associated with ischemia caused either by mural ischemia associated with the increased tension of the distended bowel wall or by arterial occlusion caused by torsion of the mesenteric arterial supply; therefore, severe abdominal pain, rebound tenderness, and tachycardia are ominous signs.
d. The radiographic findings are often dramatic and enable prompt diagnosis and treatment.
e. They usually reveal a markedly dilated sigmoid colon with the appearance of a bent inner tube with its apex in the right upper quadrant.
f. An air-fluid level may be seen in the dilated loop of colon, and gas is usually absent from the rectum.
g. CT reveals a characteristic mesenteric whorl
h. A contrast enema typically demonstrates the point of obstruction with the pathognomonic “bird's beak” deformity revealing the twist that obstructs the sigmoid lumen.