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Colonic (Large bowel) Obstruction

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Anaesthetics and Critical Care

Obstetrics Gynaecology

Trauma and Orthopaedics

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Urology

Version Jan 2023

RIF tenderness with radiological evidence of caecal distension and distal colonic obstruction is a critical sign indicating imminent caecal perforation and peritonitis. Follows Laplace's law as the tension in the wall is greatest where the diameter is maximal

Large Bowel Obstruction
ABC, IV fluids 3-4+ L/day. Caution if Heart failure Send bloods, Correct electrolytes NG tube if vomiting. Catheter. Replace losses Analgesia. Antiemetic. Cyclizine not metoclopramide Bloods Acidosis, Lactate , Raised WCC and CRP Erect and supine AXR and Erect CXR to exclude free air May need consider CT abdomen to pinpoint cause May be functional - stop causative drugs, fix K/Ca/Mg Treat any sepsis and consider HDU if very unwell Physical cause - consider surgery or other intervention

Large Bowel Obstruction

ABC, IV fluids 3-4+ L/day. Caution if Heart failure

Send bloods, Correct electrolytes

NG tube if vomiting. Catheter. Replace losses

Analgesia. Antiemetic. Cyclizine not metoclopramide

Bloods Acidosis, Lactate , Raised WCC and CRP

Erect and supine AXR and Erect CXR to exclude free air

May need consider CT abdomen to pinpoint cause

May be functional - stop causative drugs, fix K/Ca/Mg

Treat any sepsis and consider HDU if very unwell

Physical cause - consider surgery or other intervention

About

Can result in an acute surgical admission
Elderly and those on steroids may have subtle findings

Aetiology

Obstruction will lead to more progressive bowel dilation
Eventually untreated the bowel will perforate
Usually at the site of maximal diameter the caecum

Causes

Lumen: Polypoid tumour, Constipation
Mural: Malignancy, Ischaemia, Diverticulitis stricture, Radiation stricture, Pseudo-obstruction
Extramural: Hernia, Volvulus, Intussusception

Clinical

Colicky Abdominal pain, Abdominal distension
Failure of passage of flatus and stool PR
Guarding, peritonism, perforation, sepsis and shock

Investigations

FBC, U&E, ESR: Raised WCC, abnormal electrolytes
Raised lactate suggests bowel ischaemia and sepsis
ECG: may show MI or AF
CXR: Free air if perforation has occurred
AXR: Dilated bowel loops proximal to obstruction "cut off point"
Double contrast CT: shows level and cause of obstruction and viability of bowel involved. May show evidence of metastases
CT has largely replaced and helped with diagnosis

Comparison

Type	Small Bowel	Large Bowel
Abdominal Pain	Early and colicky and centrally abdominal	Pain may not be colicky
Vomiting	Early Bilious vomiting and then faecalent due to bacterial overgrowth	Vomiting late
Constipation	Late	Early. May pass diarrhoea if partial obstruction
Abdominal distension	Less if high obstruction and vomits	More severe if low
Abdominal percussion	May be resonant	May be resonant
Bowel sounds	High pitched tinkling
AXR	Central small bowel valvulae coniventae across width of bowel visible. Distended small bowel. Usually centrally. Many short fluid levels on erect film. Often many loops of the small bowel. SB usually < 3 cm and up to 5 cm when obstructed. No gas in the colon.	Peripheral large bowel and haustra do not cross the entire diameter of the wall. Gas in the large bowel. Few loops. Few long fluid levels. Transverse diameter < 10 cm.
Causes	Post surgical adhesions, herniae, volvulus, paralytic ileus, small bowel ischaemia, old irradiation damage , Crohn's disease	Colorectal cancer, Sigmoid volvulus, Diverticular disease

Management

Urgent resuscitation with fluids and correct electrolytes
Analgesia and antiemetic may be needed.
NG tube if vomiting and urinary catheter may be needed
Those with signs of peritonitis or perforation or necrosis then emergency laparotomy and colonic resection and usually a colostomy is done
Antibiotics are used to cover gram-negative and anaerobic organisms
In some cases Palliation is appropriate

References

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. The official launch will be at the end of 2018. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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