About 3.2 million cases of bowel obstruction occurred in 2015 which resulted in 264,000 deaths.[3][7] Both sexes are equally affected and the condition can occur at any age.[6] Bowel obstruction has been documented throughout history, with cases detailed in the Ebers Papyrus of 1550 BC and by Hippocrates.[8]
In small bowel obstruction, the pain tends to be colicky (cramping and intermittent) in nature, with spasms lasting a few minutes. The pain tends to be central and mid-abdominal. Vomiting may occur before constipation.[10] Common physical exam findings may include signs of dehydration, abdominal distension with tympany, nonspecific abdominal tenderness, and high pitched tinkly bowel sounds.[11]
In large bowel obstruction, the pain is felt lower in the abdomen and the spasms last longer. Common symptoms include abdominal pain, distension, and severe constipation.[12] Constipation occurs earlier and vomiting may be less prominent. Proximal obstruction of the large bowel may present as small bowel obstruction.[13] Patients may notice a history of bloating and narrowing of stools before the onset of more severe symptoms. Symptoms can present quickly in the cases of volvulus and can present over a longer period of time in the setting of cancer. Common physical exam findings may include a palpable hernia, abdominal distension with tympany, nonspecific lower abdominal tenderness, and a rectal mass.[6]
Radiological signs of bowel obstruction include bowel distension (small bowel loops dilated >3 cm) and the presence of multiple (more than 2) air-fluid levels on supine and erect abdominal radiographs.[16] Ultrasounds may be as useful as CT scanning to make the diagnosis.[17]
Contrast enema or small bowel series or CT scan can be used to define the level of obstruction, whether the obstruction is partial or complete, and to help define the cause of the obstruction. The appearance of water-soluble contrast in the cecum on an abdominal radiograph within 24 hours of it being given by mouth predicts resolution of an adhesive small bowel obstruction with sensitivity of 97% and specificity of 96%.[18]
Colonoscopy, small bowel investigation with ingested camera or push endoscopy, and laparoscopy are other diagnostic options.
After abdominal surgery, the incidence of small bowel obstruction from any cause is 9%. In those where the cause of the obstruction was clear, adhesions are the single most common cause (more than half).[22]
Narcotic induced (especially with the large doses given to cancer or palliative care patients)
Outlet obstruction
Outlet obstruction is a sub-type of large bowel obstruction and refers to conditions affecting the anorectal region that obstruct defecation, specifically conditions of the pelvic floor and anal sphincters. Outlet obstruction can be classified into four groups.[24]
Functional outlet obstruction
Inefficient inhibition of the internal anal sphincter
Treatment of small and large bowel obstructions are initially similar and non-operative management is usually the initial management strategy as the majority of small bowel obstruction resolve spontaneously with non-operative management.[25][26] Patients are monitored by the surgical team for signs of improvement and resolution of the obstruction on imaging; if the obstruction does not clear then surgical management for the treatment of the causative lesion is required.[27] In malignant large bowel obstruction, endoscopically placed self-expanding metal stents may be used to temporarily relieve the obstruction as a bridge to surgery,[28] or as palliation.[29] Diagnosis of the type of bowel obstruction is normally conducted through initial plain radiograph of the abdomen, luminal contrast studies, computed tomography scan, or ultrasonography prior to determining the best type of treatment.[30]
Further research is needed to find out if parenteral nutrition is of benefit to people with an inoperable blockage of the bowel caused by advanced cancer.[31]
Decreasing recurrent bowel obstructions, improving quality of life with physiotherapy with the Wurn Technique: Physical Therapy is used to decrease the chance of recurrent bowel obstructions by breaking up adhesions that prevent proper flowage of stool.[32] A control-based study was performed to examine the efficacy of manual physical therapy on the pain level and quality of life showing a dramatic improvement.[33] Two patients from this case study that had small bowel obstruction due to adhesions have shown successful resolution of symptom presentation of partial SBO and sustained results were observed in the treatment of these patients.[34] The results of the questionnaire after these studies were conducted were on the patients' quality of life in respect to diet, pain gastrointestinal symptoms, and daily life. The results of this questionnaire using 149 patients showed a Chronbach Alpha of 0.86. Test retest reliability was evaluated with 72 normal subjects, the correlation coefficient was 0.93.[35]
Small bowel obstruction
In the management of small bowel obstructions, a commonly quoted surgical aphorism is: "never let the sun rise or set on small-bowel obstruction"[36] because about 5.5%[36] of small bowel obstructions are ultimately fatal if treatment is delayed. Improvements in radiological imaging of small bowel obstructions allow for confident distinction between simple obstructions, that can be treated conservatively, and obstructions that are surgical emergencies (volvulus, closed-loop obstructions, ischemic bowel, incarcerated hernias, etc.).[2] Exam findings of bowel compromise requiring immediate surgery include: severe abdominal pain, signs of peritonitis such as rebound tenderness, elevated heart rate, fever, and elevated inflammatory markers on lab work, such as lactic acid.[37][38]
A small flexible tube (nasogastric tube) may be inserted through the nose into the stomach to help decompress the dilated bowel. This tube is uncomfortable but relieves the abdominal cramps, distention, and vomiting. Intravenous therapy is utilized and the urine output may be monitored with a catheter in the bladder.[39][40]
Most people with SBO are initially managed conservatively because in many cases, the bowel will open up. Some adhesions loosen up and the obstruction resolves. The patient is examined several times a day, and X-ray images are made to ensure he or she is not getting clinically worse.[41]
Conservative treatment involves insertion of a nasogastric tube, correction of dehydration and electrolyte abnormalities. Opioid pain relievers may be used for patients with severe pain but alternate pain relievers are preferred as opioids can decrease bowel motility.[42]Antiemetics may be administered if the patient is vomiting. Adhesive obstructions often settle without surgery. If the obstruction is complete surgery is usually required.
Most patients improve with conservative care in 2–5 days. When the obstruction is cancer, surgery is the only treatment. Those with bowel resection or lysis of adhesions usually stay in the hospital a few more days until they can eat and walk.[43]
The prognosis for non-ischemic cases of SBO is good with mortality rates of 3–5%, while prognosis for SBO with ischemia is fair with mortality rates as high as 30%.[44]
Cases of SBO related to cancer are more complicated and require additional intervention to address the malignancy, recurrence, and metastasis, and thus are associated with a more poor prognosis.[45] Surgical options in patients with malignant bowel obstruction need to be considered carefully as while it may provide relief of symptoms in the short term, there is a high risk of mortality and re-obstruction.[46]
All cases of abdominal surgical intervention are associated with increased risk of future small-bowel obstructions. Statistics from U.S. healthcare report 18.1% re-admittance rate within 30 days for patients who undergo SBO surgery.[47] More than 90% of patients also form adhesions after major abdominal surgery.[48]
Common consequences of these adhesions include small-bowel obstruction, chronic abdominal pain, pelvic pain, and infertility.[48]
^Gottlieb M, Peksa GD, Pandurangadu AV, Nakitende D, Takhar S, Seethala RR (February 2018). "Utilization of ultrasound for the evaluation of small bowel obstruction: A systematic review and meta-analysis". The American Journal of Emergency Medicine. 36 (2): 234–242. doi:10.1016/j.ajem.2017.07.085. PMID28797559. S2CID24769945.
^Young CJ, Suen MK, Young J, Solomon MJ (October 2011). "Stenting large bowel obstruction avoids a stoma: consecutive series of 100 patients". Colorectal Disease. 13 (10): 1138–41. doi:10.1111/j.1463-1318.2010.02432.x. PMID20874797. S2CID12724976.
^Mosler P, Mergener KD, Brandabur JJ, Schembre DB, Kozarek RA (February 2005). "Palliation of gastric outlet obstruction and proximal small bowel obstruction with self-expandable metal stents: a single center series". Journal of Clinical Gastroenterology. 39 (2): 124–8. PMID15681907.