09 January 2011

While on placement this week we had a patient arrive via Accident and Emergency (A&E) with a suspected abdominal obstruction. An abdominal obstruction is where there is a suspected obstruction in the small or large bowel which has become impacted. Patients being referred for suspected abdominal obstruction have to be in an upright position. The contents of the intestine and movement and motion can come to complete arrest. Symptoms usually include cramping pain, vomiting, obstinate constipation, and lack of flatus. Clinical diagnosis is confirmed through an abdominal X-ray. After carrying out the abdominal x-ray on this particular patient it was evident she had something unusual going on as the centralised part of her small bowel was extremely dilated.
Common causes of abdominal obstruction can be adhesions which usually develop after some form of pelvic surgery, hernias, and tumors. Other causes are diverticulitis, foreign bodies such as gallstones, and volvulus (twisting of bowel on its mesentery). However specific segments of the intestine are affected differently.
In a simple abdominal obstruction, a blockage can occur without any compromise to the vascular supply. All foods, fluids and digestive secretions ingested after an obstruction has occurred along with any gas accumulate above the obstruction. This causes the proximal bowel to distend, and the distal segment to collapse. This then causes the normal process of absorption and secretions of the mucosa to become depressed and congested. The bowel walls then reach deluge due to an excessive accumulation of serous fluid in the tissue spaces in the body cavity. The abdominal cavity then progresses to distend, causing strengthened peristalsis (contraction and relaxation of the alimentary canal) and an upset of the normal condition and functioning of secretions. This then increases the risks of dehydration and the advancement to a strangulating obstruction.
Strangulation of the obstructed bowel causes a compromised blood flow and can occur in a significant number of patients with small bowel obstructions. A strangulated obstruction can progress to infarction (an area of tissue death (necrosis) due to a lack of oxygen caused by obstruction) and gangrene in a short period of time.
Venous obstruction occurs first, followed by arterial occlusion (closure or blockage of a blood vessel), resulting in rapid ischemia. The ischemic bowel becomes a deluge with edema and infarcts (areas of tissue death), leading to gangrene and perforation.

Perforation can occur in an ischemic section (typically small bowel) or when there is a large amount of dilation. Perforation risk increases when the cecum is dilated to a diameter equal to or greater than 13 cm.
Symptoms and signs from an obstruction of the small bowel are usually;
• abdominal cramps around the umbilicus,
• vomiting
• partial obstruction may develop diarrhea.
• absence of strangulation, the abdomen is not tender.
• Hyperactive, high-pitched peristalsis with rushes coinciding with cramps
• dilated loops of bowel maybe palpable
• infarction, the abdomen becomes tender and auscultation reveals a silent abdomen or minimal peristalsis.
• Shock and oliguria (a low output of urine) indicate late simple obstruction or strangulation.
Symptoms and signs of a large bowel obstruction are milder symptoms. These develop gradually differing from small-bowel obstruction.
• Increasing constipation leads to obstinate constipation and distention of the abdomen
• Vomiting may occur
• Lower abdominal cramps and non-production of feces
• Examination usually shows a distended abdomen with gurgling sound caused by the movement of gas in the intestines (borborygmi).
• no tenderness, and an empty rectum
• mass corresponding to the site of an obstructing tumor may be palpable.
• Systemic symptoms are usually mild, with fluid and electrolyte deficits being uncommon.

Care for patients with small and large bowel obstruction is similar. Treatment used for an obstructed bowel can be, Nasogastric suction, IV fluids and IV antibiotics if bowel ischemia suspected. Sometimes specific measures of resection are need in adults with an obstruction of the duodenum.
If the obstruction is caused by diverticulitis a perforation is often present. If a perforation is evident then removal of the section involved is required. Resection and colostomy are then carried out, and the joining of blood vessels (anastomosis) is postponed.

Carver, E. and Carver, B. 2006. Medical imaging: techniques, reflection and evaluation. Edinburgh: Churchill Livingston Elsevier.

http://digestive.niddk.nih.gov/ddiseases/pubs/intestinaladhesions/AbdominalAdhesions.pdf

http://www.merckmanuals.com/professional/sec02/ch011/ch011h.html#BGBBGBGG

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This entry was posted on Sunday, January 9th, 2011 at 11:06 am and is filed under Reflectives. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.