CBC, chem 7
LFTs, lipase, PT/PTT
Lactate
UA, Upreg (if female)
CT abdomen/pelvis
Gastric<unk> 
Upright CXR and abdominal Xray
Intrathoracic, upside-down stomach
Double air fluid level in stomach
Collapsed small bowel
CT
Gastric herniation around points of torsion
Ischemia seen a lack of contrast enhancement of gastric wall
Cecal<unk> 
Abdominal Series X-rays
Not definitive in many cases
Dilated cecum with air fluid level
Distended small bowel
Distal colon with paucity of gas
"Coffee bean sign"-Large oval gas shadow with line down middle in middle of abdomen
Free air on upright chest/lateral decubitus if perforation
Contrast enema
Helpful to differentiate between sigmoid/cecal<unk> 
Ultrasound
Not particularly helpful
CT
Mesocolon "whirl sign"- twisted mesentery
Many only definitively diagnosed at surgery
Sigmoid<unk> 
Abdominal Series X-rays
May not be diagnostic
Grossly distended loop of colon (no haustral markings) either on R/L side.
Coffee-bean sign
"Bent inner tube" sign
Free air on upright chest/lateral decubitus if perforation
Contrast enema
Bird's beak sign-contrast fills colon up to point of torsion
Sigmoidoscopy (both diagnostic and therapeutic)
CT
Upright CXR and abdominal Xray
Intrathoracic, upside-down stomach
Double air fluid level in stomach
Collapsed small bowel
CT
Gastric herniation around points of torsion
Ischemia seen a lack of contrast enhancement of gastric wall
Intrathoracic, upside-down stomach
Double air fluid level in stomach
Collapsed small bowel
Gastric herniation around points of torsion
Ischemia seen a lack of contrast enhancement of gastric wall
Abdominal Series X-rays
Not definitive in many cases
Dilated cecum with air fluid level
Distended small bowel
Distal colon with paucity of gas
"Coffee bean sign"-Large oval gas shadow with line down middle in middle of abdomen
Free air on upright chest/lateral decubitus if perforation
Contrast enema
Helpful to differentiate between sigmoid/cecal<unk> 
Ultrasound
Not particularly helpful
CT
Mesocolon "whirl sign"- twisted mesentery
Many only definitively diagnosed at surgery
Not definitive in many cases
Dilated cecum with air fluid level
Distended small bowel
Distal colon with paucity of gas
"Coffee bean sign"-Large oval gas shadow with line down middle in middle of abdomen
Free air on upright chest/lateral decubitus if perforation
Helpful to differentiate between sigmoid/cecal<unk> 
Not particularly helpful
Mesocolon "whirl sign"- twisted mesentery
Abdominal Series X-rays
May not be diagnostic
Grossly distended loop of colon (no haustral markings) either on R/L side.
Coffee-bean sign
"Bent inner tube" sign
Free air on upright chest/lateral decubitus if perforation
Contrast enema
Bird's beak sign-contrast fills colon up to point of torsion
Sigmoidoscopy (both diagnostic and therapeutic)
CT
May not be diagnostic
Grossly distended loop of colon (no haustral markings) either on R/L side.
Coffee-bean sign
"Bent inner tube" sign
Free air on upright chest/lateral decubitus if perforation
Bird's beak sign-contrast fills colon up to point of torsion
Volvulus
Abdominal aortic aneurysm
Rectal foreign body
Aortocaval fistula
Anal fissure
Acute gastroenteritis
Fecal impaction
Aortoenteric fisulta