Volvulus

Question 1

Define volvulus.

Answer 1

A volvulus is when a loop of intestine twists around itself and the mesentery that supports it, resulting in a bowel obstruction.

The affected bowel can become ischaemic rapidly leading to bowel necrosis and perforation.

Question 2

Where do volvuli occur?

Answer 2

1. Most at the sigmoid colon (80%) → large bowel obstruction
2. Caecum (~20%) - in most people the caecum is retroperitoneal so not at risk of twisting but in 20% it is not retroperitoneal
3. Midgut

They can also occur at the stomach, caecum, small intestine and transverse colon, but are much rarer.

Question 3

Why is sigmoid volvulus most common?

Answer 3

The sigmoid colon has a long mesentery which increases with age making it prone to twisting on its mesenteric base

Question 4

What type of colon do you usually get in sigmoid volvulus?

Answer 4

acquired or idiopathic megacolon (large, elongated, relatively atonic colon)

Question 5

What are some general risk factors for volvulus?

Answer 5

• Age
• Chronic constipation (e.g. Hirschsprung disease) or laxative use - in the elderly big stool can act like a pivot around which the colon twists
• Previous abdominal operations - adhesions serve as pivot point
• Intestinal malformation or excessive exercise (in young patients)
• Pregnancy - fetus can cause displacement and twisting of the colon

Question 6

What are the risk factors for sigmoid volvulus?

Answer 6

• older patients
• chronic constipation
• Chagas disease
• neurological conditions e.g. Parkinson’s disease, Duchenne muscular dystrophy
• psychiatric conditions e.g. schizophrenia

Question 7

What are the risk factors for caecal volvulus?

Answer 7

• all ages
• adhesions
• pregnancy

Question 8

Which type of volvulus do babies commonly get and why?

Answer 8

Midgut volvulus - as a result of abnormal intestinal development in foetus i.e. when in embryonic development the appendix and caecum stay in the RUQ instead of descending → midgut volvulus

Question 9

What are the consequences of volvulus?

Answer 9

• Bowel pinched shut → obstruction
• Mesentery can be twisted and blood supply cut off → infarction → bloating, constipation, severe pain, bloody stool and SEPSIS

Question 10

What investigations should you do for volvulus?

Answer 10

AXR - usually DIAGNOSTIC - sigmoid looks like COFFEE BEAN in LIF; if the ileocaecal valve is incompetent, the AXR will also show signs of small bowel dilatation. In caecal there will be small bowel dilatation.

Question 11

What is the management of obstruction in a patient in A&E?

Answer 11

NBM

Analgesia

IV fluids

NG Ryles tube - drip and suck

IV abx

Refer to surgeons +/- request CT

Question 12

How is volvulus usually managed?

Answer 12

Decompression

• Sigmoid volvulus → RIGID sigmoidoscopy with rectal tube insertion
• Caecal volvulus → usually SURGICAL but occasionally colonoscopy can be used

Flatus tube is usually left for 24hrs after decompression but usually unsuccessful and flexible sigmoidoscopy must be inserted

Surgery - for midgut volvulus - within 2 days or immediately is bowel severely twisted/blood supply cut off. Normally involved untwisting of colon and attaching intestine to abdominal wall. In severe cases (e.g. infarction) pieces of intestine should be removed → stoma (loop ileostomy)

Question 13

What are the symptoms of volvulus?

Answer 13

• Sudden onset colicky pain in lower abdomen
• Bloating
• Failure to pass flatus or stool
• Constipation
• Vomiting (late)
• Fever (late)

Question 14

What are the signs of volvulus on examination?

Answer 14

• Tympanic, distended (but usually non-tender) andomen
• Palpable mass may be present
• DRE shows only empty rectal ampulla

Question 15

What ages are affected by volvulus?

Answer 15

Bimodal

10-29yrs

60-79yrs

Question 16

What does the 3,6,9 rule refer to in AXR?

Answer 16

Small bowel = 3cm diameter

Caecum = 9cm

Colon = 6cm

NB: valvulae conniventes = small bowel

haustral lines = large bowel

Question 17

Summarise the main causes of SBO vs LBO.

Answer 17

SBO - adhesions and hernia

LBO - malignancy, diverticular disease, volvulus

Question 18

List the 5 classes of causes of obstruction.

Answer 18

1. Mechanical - partial or complete classified further into… (see below)
2. Functional - paralytic ileus, CES (cauda equina), pesudo-obstruction e.g. Ogilvie syndrome
3. Simple - obstructed with adequate blood supply
4. Strangulated- obstructed without adequate blood supply
5. Closed-loop - volvulus