Bowel obstruction

Question 1

What are the two types of bowel obstruction?

Answer 1

Mechanical and functional

Question 2

What is mechanical?

Answer 2

→ physical obstruction, blocking passage of faeces, wind etc

→ there is motility, the problem is with the physical obstruction

→ bowel is distended before the obstruction, and decompressed after the obstruction

Question 3

What is functional?

Answer 3

→ motility is the problem (muscle problem)

→ bowel is distended THROUGHOUT

Question 4

Symptoms? (CAVO)

Answer 4

cramping
abdominal distention
vomiting
obstipation

Question 5

3 SBO mechanical causes?

Answer 5

• commonly surgical adhesions that stick the bowel closed
• bowel hernias (femoral, inguinal)
• intussusception (usually in children with Meckel’s diverticulum)

Question 6

2 LBO mechanical causes?

Answer 6

• neoplasm (eg colorectal cancer)
• volvulus (twisting of the bowel)
  Volvulus: in seniors with chronic constipation, poop builds up in sigmoid, and it twists on itself.

Question 7

SBO functional cause and what you see on xray?

Answer 7

• paralytic ileus
• dilated loops of small bowel that are consistent (>3cm)

Question 8

PPPP, causes of paralytic ileus?

Answer 8

• Peritonitis (causing bad smooth muscle contraction)
• Post abdominal surgery
• Potassium decrease (decrease contractility)
• Pain meds (opioids)

Question 9

LBO functional cause?

Answer 9

• colonic pseudo-obstruction
• dilated loops of large bowel (>6cm)
• telltale gigantic caecum (>9cm)
• complete decompression

Question 10

Hypovolemia cause?

Answer 10

1. Vomiting = loss of water and Na+/K+/H+
2. Bowel distension = bowel wall edema = decreased fluid uptake
3. More fluid secretion into bowel lumen

Question 11

Hypokalemia and metabolic alkalosis cause?

Answer 11

1. Vomiting = loss of water and Na+/K+/H+

Question 12

How does bowel ischemia/perforation form?

Answer 12

• increase in intraluminal pressure, compressing arteries
• bowel ischemia, areas of necrotic tissue (bacteria can now cross GI wall and cause sepsis)
• necrotic tissue will go into anaerobic respiration, producing lactate. If someone has obstruction and lactate starts climbing…
• necrotic tissue can perforate due to intraluminal pressure
• bacteria can infect the peritoneum

Question 13

Findings in ischemia and perforation?

Answer 13

Ischemia → fever, lactate

Perforation → peritoneal findings, pneumoperitoneum

Question 14

What are you looking for on x-ray?

Answer 14

1. Dilated bowel loops
2. Air
3. Pneumoperitoneum
   then obtain CTAP

Question 15

What will you find if mechanical?

Answer 15

1. obstruction
2. bowel sounds

Question 16

What will you find if functional?

Answer 16

1. Dilated colon -> Ogilvie syndrome
2. Dilated small bowel -paralytic ileus

Question 17

Mechanical treatment?

Answer 17

Bowel decompression.
1.IVF while NGO and NGT suction
2. Partial obstruction -> gastrografin to reduce wall edema
3. ischemia/perf -> surgery, endoscopy

Question 18

Functional treatment?

Answer 18

1.IVF while NGO and NGT suction
2. bowel motility -> laxative
3. ischemia -> surgery