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Radiographic Def.

3-6-9 Rule Rule on XR, > 2.5 on CT

3 cm for small intestine
6 cm for large intestine
9 cm for cecum </aside>

Screening Questions

Lack of flatulence, Bowel movement

Presentation

Signs and Symptom

Sign/Symptom	Mechanical jCause	Suggestive of (more likely to be)
Abdominal distension	bowel distension +/- Ascites	NA
‣	Local distension triggers mechanoreceptors, activating afferent vagus and splanchnic nerves to chemo receptors trigger zone.	SBO - Small Bowel Obstruction
‣	NA	Complete obstruction
+/- crampy ‣ (‣ / Diffused Abdominal Pain)	NA	mechanical obstruction, if worse with movement or palpation suggests ‣

Physical Exam

Routine Abdominal Exam
- Auscultation
  - Hyperactive bowel sounds may be present, as may borborygmi.
  - However, if a paralytic picture predominates, bowel sounds may be absent
- Percussion
  - won’t be painful, except for Bowel ischemia : strangulated Hernia
  - differentiate predominant causes of Abdominal distension:
    - tympanic note: intestinal obstruction
    - dull note: malignant Ascites
- Deep palpation won’t be painful
- Feel mass:
  - Cancer
  - Inflammatory reaction (e.g. local perforation)

DDx

Screenshot 2024-05-14 at 3.37.49 PM.png

By Anatomy

SBO - Small Bowel Obstruction Top 3 causes → 60%

Adhesion from prior surgery or infection
Hernia

LBO - Large Bowel Obstruction Top 3 causes → 30%

(10% simultaneously)

By Etiology

Malignancy

Primary tumor, e.g. CRC - Colorectal cancer
Metastasis
Peritoneal Carcinomatosis