Volvulus Flashcards
Define volvulus.
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.
Where do volvuli occur?
- Most at the sigmoid colon (80%) → large bowel obstruction
- Caecum (~20%) - in most people the caecum is retroperitoneal so not at risk of twisting but in 20% it is not retroperitoneal
- Midgut
They can also occur at the stomach, caecum, small intestine and transverse colon, but are much rarer.
Why is sigmoid volvulus most common?
The sigmoid colon has a long mesentery which increases with age making it prone to twisting on its mesenteric base
What type of colon do you usually get in sigmoid volvulus?
acquired or idiopathic megacolon (large, elongated, relatively atonic colon)
What are some general risk factors for volvulus?
- 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
What are the risk factors for sigmoid volvulus?
- older patients
- chronic constipation
- Chagas disease
- neurological conditions e.g. Parkinson’s disease, Duchenne muscular dystrophy
- psychiatric conditions e.g. schizophrenia
What are the risk factors for caecal volvulus?
- all ages
- adhesions
- pregnancy
Which type of volvulus do babies commonly get and why?
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
What are the consequences of volvulus?
- Bowel pinched shut → obstruction
- Mesentery can be twisted and blood supply cut off → infarction → bloating, constipation, severe pain, bloody stool and SEPSIS
What investigations should you do for volvulus?
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.
What is the management of obstruction in a patient in A&E?
NBM
Analgesia
IV fluids
NG Ryles tube - drip and suck
IV abx
Refer to surgeons +/- request CT
How is volvulus usually managed?
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)
What are the symptoms of volvulus?
- Sudden onset colicky pain in lower abdomen
- Bloating
- Failure to pass flatus or stool
- Constipation
- Vomiting (late)
- Fever (late)
What are the signs of volvulus on examination?
- Tympanic, distended (but usually non-tender) andomen
- Palpable mass may be present
- DRE shows only empty rectal ampulla
What ages are affected by volvulus?
Bimodal
10-29yrs
60-79yrs
List the 5 classes of causes of obstruction.
- Mechanical - partial or complete classified further into… (see below)
- Functional - paralytic ileus, CES (cauda equina), pesudo-obstruction e.g. Ogilvie syndrome
- Simple - obstructed with adequate blood supply
- Strangulated- obstructed without adequate blood supply
- Closed-loop - volvulus
