Acute Intestinal Obstructions Overview

Study Notes

Acute intestinal obstruction (OIA) is a syndrome characterized by a complete and permanent cessation of normal intestinal transit (matter) and gas.
It's a serious abdominal emergency, often impacting vital prognosis.
Requires hospitalization in surgical care and frequently leads to surgical intervention before complications arise.

The intestine is a hollow, dynamic organ composed of the 1.5m colon (with mobile and fixed segments) and the 6.5m small intestine (duodenum, jejunum, and ileum) located centrally and having mobile parts.
The intestine includes various structures like the esophagus, stomach, and colon, alongside various contents (air, liquids, food, bacteria).
Obstructions can be categorized as high (duodenum and small intestine) or low (colon and rectum).

Mechanical: Caused by a physical blockage.
- Strangulation: Associated with a loop of intestine being twisted (volvulus), trapped (incarceration) or constricted by a band (mesenteric twisting), or caused by internal or external pressure (like hernia), affecting blood supply.
- Obstruction: Caused by various blockages within the intestinal wall, including tumors, foreign bodies (like gallstones or bezoars), or adhesions.
Functional: Resulted from a disruption in the intestine's normal motility, often from a paralytic ileus.
- Triggers include infections (appendicitis, peritonitis), inflammation (pancreatitis), pain (kidney stones), or various other causes.

Consequences of mechanical obstruction:
- The intestinal wall proximal to the blockage thickens and narrows.
- Blood flow is reduced within the intestinal walls which leads to hypoxia and tissue damage.
- Fluid leaks into the intestinal lumen (inside the bowels); also possible leakage into the peritoneal cavity.
- Gradual or sudden loss of bowel function leads to potentially severe or fatal infections.
Functional Obstructions:
- Often linked to infections or inflammatory processes, and are characterized by decreased or absent bowel sounds(often silent).
- Symptoms include fever, pain, infection, or inflammatory responses.

Functional Signs:
- Pain (location, onset, intensity, and type).
- Vomiting (timing, content).
- Cessation of bowel movements, and gas.
Physical Examination:
- Inspection (looking for distention, tenderness, and hernias).
- Percussion (assessing for air and fluid).
- Palpation (identifying tenderness and masses).
- Auscultation (listening for bowel sounds, to detect peristalsis).
- Pelvic Examination (looking for masses, fecalom).
General Signs:
- Pulse
- Temperature.
- Blood Pressure.
- Urinalysis.
Radiological Investigations:
- Abdominal X-ray (ASP).
  - Characteristics of obstruction on X-ray.
- Contrast Enema/Laverment.
- Ultrasound (echography).
- CT scans (TDM).
Diagnostic Considerations:
- Use of coloscopy as a preliminary procedure if there is no fever, and no suspected mechanical causes were found by other methods.

Small bowel obstruction:
- Strangulation (volvulus, hernia, intussusception).
- Obstructions (tumors, foreign bodies, adhesions).
Large bowel obstruction:
- Strangulation (volvulus, intussusception).
- Obstructions (tumors, strictures).
Functional obstructions:
- Infectious or inflammatory conditions in the abdomen.

Initial:
- Supporting the patient (e.g. hydration, hydration with IV, nutritional support).
- Tubes (e.g., nasogastric, large vein)
- Antibiotics when necessary.
Surgical:
- Required in most mechanical obstruction cases.
- Removal of the obstruction(s).
- Repairing or removing damaged parts of the gut (if present).
Resection: Removal of parts of the intestine in certain conditions.

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