Bowel obstruction Flashcards by Emily Stephens

What is a bowel obstruction?

Mechanical or functional problem that inhibits the normal movement of gut contents

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Common causes of bowel obstructions in children vs adults

children:
- intussusception
- intestinal atresia

adults:
- adhesions
- incarcerated hernias
- malignancy

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What are the three most common causes of bowel obstruction?

adhesions (small bowel)
hernias (small bowel)
malignancy (large bowel)

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What is intussusception?

When one part of the gut tube telescopes into an adjacent section

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Clinical presentation of intussusception

Adnominal pain
Vomiting
Haematochezia (fresh red rectal bleeding)

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Treatment of intussusception

Air enema (reverses telescoping)
Surgery

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Causes of small bowel obstruction

intra abdominal adhesions
hernias
Crohn’s disease strictures
gallstone ileus (rare)

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What are intra-abdominal adhesions?

Abnormal fibrous bands between organs, tissues or both in abdominal cavity that are normally separate

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Causes of intestinal adhesions

pelvic or abdominal surgery
peritonitis
abdominal or pelvic infection e.g. PID
endometriosis

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Clinical presentation of small bowel obstruction

nausea + vomiting (bilious) (early on)
abdominal colicky pain + distension
absolute constipation (later on)

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Diagnosis of small bowel obstructions

History
Physical exam: abdominal distension, presence of hernias, high pitched tinkling bowel sounds
Imaging

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Who does large bowel obstruction more commonly occur in?

Older patients

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Causes of large bowel obstructions

Colon cancer (most common)
Diverticular disease
Volvulus - sigmoid, caecal

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What is a closed loop obstruction?

There is a complete obstruction distally and proximally in the given segment of the intestine

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What can cause a closed loop obstruction?

adhesions
hernias
volvulus
single point obstruction with competent ileocaecal valve

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function of ileocaecal valve

prevents back movement of intestinal contents from caecum to the ileum

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Presentation of large bowel obstruction

symptoms appear gradually if cancer + abruptly with volvulus
absolute constipation (early)
abdominal distension
cramps abdominal pain
nausea + vomiting (late)

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Diagnosis of large bowel obstruction

History
Physical exam
abdominal x ray
CT abdo-pelvis with IV contrast

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What imaging is used to determine the cause of an obstruction?

CT abdo-pelvis with IV contrast

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What are the upper limits of normal bowel diameter on xray?

3cm small bowel
6cm colon
9cm caecum

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what is a volvulus?

Part of the colon twists around its mesentery > closed loop obstruction

Where are volvulus most likely to occur?

Sigmoid colon (older people)
Then caecum (younger people)

What is a risk factor for volvulus?

High fibre diets
neuropsychiatric disorders e.g. Parkinsons
nursing home residents
chronic constipation
pregnancy
adhesions

Presentation of volvulus

vomiting (particularly bilious)
abdominal distention
diffuse abdominal pain
absolute constipation

Diagnosis of volvulus

Abdominal x ray - **coffee bean sign for sigmoid** - **fetus sign for caecum** Contrast CT abdo pelvis - **whirl sign for sigmoid**

management of volvulus

- nil by mouth, NG tube + IV fluids - analgesia - correct electrolyte imbalances - **conservative**: decompression by sigmoidoscope or insertion of a flatus tube (sigmoid) - **surgical management**: laparotomy, hartmann's procedure(

outline sigmoidoscope decompression

- pt in left lateral position - sigmoidoscopy inserted into rectum - volvulus is gentle untwisted

Management of sigmoid volvulus

- **conservative**: sigmoidoscope decompression or insertion of flatus tube** - **surgical**: open abdominal surgery or hartmann's procedure

Surgical management of caecal volvulus

right hemicolectomy - bowel resection

what is laparotomy?

open abdominal surgery

Compare the symptoms of small and large bowel obstruction

_Small_: - colicky pain more frequently - vomiting occurs early - constipation occurs later _Large_: - vomiting occurs later - constipation occurs earlier

Causes of small bowel obstruction in children vs adults

_children_: - intussuscpetion - malrotation - hernias . _adults_: - adhesions - hernias - crohn’s strictures

Causes of large bowel obstructions in children vs adults

_children_: - Hirschsprung’s disease . _adults_: - colon cancer - diverticulitis - volvulus

What is Hirschprung’s disease

- congential disorder of colon where there is a lack of myenteric + submucosal plexuses - parasympathetic neuroblasts fail to migrate from neural crest to distal colon > developmental failure of meissner + Auerbach plexuses - causing hypomobility + constipation

Management of bowel obstruction

- full set of bloods - VBG - **'drip + suck'**: nil by mouth, IV fluids, NG tube with free drainage - definitive management with surgery: adhesiolysis, hernia repair, emergency resection, stents

outline drip and suck management of bowel obstruction

- nil by mouth - IV fluids - NG tube with free drainage

Surgical management of bowel obstruction

depends on cause of obstruction - adhesiolysis - hernia repair - emergency resection of obstructing tumour - stent for obstructive tumour during colonoscopy

complications of bowel obstruction

- bowel perforation - bowel ischaemia - leading to faecal peritonitis

Presentation of bowel ischaemia

- rebound + percussion tenderness - guarding - high lactate on ABG

Causes of upper GI perforation

- peptic ulcer disease - gastric or oesophageal cancer - foreign body ingestion *e.g battery* - excessive vomiting

Causes of lower GI perforation

- diverticulitis - colorectal cancer - appendicitis - foreign body insertion - Crohn’s disease - toxic megacolon

Causes of bowel perforation anywhere

- iatrogenic *e.g. gastroscopy, colonoscopy* - trauma - mesenteric ischaemia - bowel obstruction

Presentation of gastrointestinal perforation

- rapid onset, severe abdominal pain - systemically unwell - features of peritonitism

Features of peritonisim

- abdomen rigidity - guarding - rebound tenderness - percussion tenderness - systemically unwell

Presenation of thoracic perforation

- chest or neck pain - radiation of pain to back - worse on inspiration - pleural effusion signs of auscultation + percussion

Gold standard diagnosis of perforation

**CT with IV contrast** (Possibly oral if upper GI)

Investigations of GI perforation

- CT scan with IV contrast - erect chest X-ray - abdominal x ray

Features of GI perforation on abdominal X-ray

- **Rigler’s sign**: both sides of the bowel visible - **psoas sign**: loss of the sharp delineation of the psoas muscle border

Management of GI perforation

- NBM - IV fluid resuscitation - analgesia - locate underlying cause - surgery depends on the perforation site - Graham’s patch - resection + intra-operative washout

What is a graham’s patch?

Surgery to treat perforated peptic ulcer - piece of omentum used to close perforated site