Small Bowel Obstruction (SBO) and Gas in the Portal System

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

86-year-old Caucasian female (CF) was admitted from a nursing home (NH) with a one week history of loose stools, and a 4-day history of nausea and vomiting. She also complained of (c/o) distended abdomen with crampy abdominal pain. For the last two days, attempts have been made at managing her at the nursing home with intravenous (IV) fluids and antiemetics. She had no urinary complaints.

Past medical history (PMH)

Coronary artery disease (CAD), congestive heart failure (CHF), hypertension (HTN), peptic ulcer disease (PUD), osteoporosis and macular degeneration.

Past surgical history (PSH)

Hysterectomy and placement of a permanent pacemaker.


Potassium (KCl), atorvastatin (Lipitor), lisinopril, Protonix (pantoprazole), aspirin, Coreg (carvedilol), Digitek (digoxin oral), and Lasix (furosemide).


She has reportedly multiple allergies including penicillin (PCN), Altace (ramipril), Prevacid (lansoprazole), Norvasc (amlodipine), Ceclor (cefaclor), and Meclomen (meclofenamate).

Physical examination:

Vital signs (VS) 36-74-36-158/88.
Appears acutely ill, she is in moderate distress and lethargic but arousable
Chest: bibasilar rhonchi, tachypneic
CVS: Clear S1S2
Abdomen: Distended and tympanic. She has generalized epigastric tenderness with mild guarding and rebound. Bowel sounds are hyperactive. Rectal exam showed heme negative stool.

What is the most likely diagnosis?

- Small bowel obstruction (SBO) vs. large bowel obstruction (LBO)
- Digoxin ("Dig") toxicity
- Ischemic colitis
- Gastroenteritis
- C. diff. colitis

What laboratory workup would you suggest?

CBCD, CMP, Dig level, UA, Stool WBC, C&S, O&P, KUB
What about a CT of the abdomen?

Laboratory results: WBC 16.4/mm3, hemoglobin 13 mg/dL, platelets were 269,000/mm3. She had 86% PMN, and no bands. Her white count at earlier this morning was 10.8/mm3.

CBCD, note the elevated WBC with 86% PMN and the appearance of bands (36%) several hours later (click to enlarge the images).

BMP in SBO - note the development of metabolic acidosis (click to enlarge the images).

Amylase and lipase are normal. Urinalysis is normal. Digoxin level is 1.2.

Abdominal X-rays - 3 views:

AXR: Lateral view, SBO, dilated small bowel loops, one air-fluid level (right). Pacemaker; Air-fluid level close-up (click to enlarge the images).

SBO, multiple dilated small bowel loops. Close-up: note the valvulae crossing the lumen from side to side; in LBO the haustrae cross only half-way (click to enlarge the images).

Radiology report: Very prominent gaseous distention of multiple loops of small bowel overlying the lower abdomen and pelvis. Associated air fluid levels are noted on decubitus films. These findings are suspicious for SBO, with associated prominent gastric distention and large air fluid level overlying stomach. No obvious free air is identified. There is severe dextroscoliosis.

What happened?

The patient was admitted to the intensive care unit. She also had CT scan of the abdomen and pelvis in the ER. The working diagnosis was bowel obstruction.

Before the patient went to CT scan, a NG was put and 1200 cc of fecal like material was drained, and then about 400 cc of contrast was passed per NG tube prior to CT.

What happened next?

The CT scan showed gas in the portal system.

CT chest and abdomen: Note the metallic reflections in the heart due to the pacemaker wires. Calciffication in the aorta, contrast in the stomach (click to enlarge the images).

Gas in the portal system. Note also the severe scoliosis (click to enlarge the images).

Gas in the portal system. Dilated stomach half-filled with contrast (click to enlarge the images).

Dilated small bowel loops with air-fluid levels (click to enlarge the images).

Radiology report of CT abdomen and pelvis with IV and oral contrast:

Severe dextroscoliosis, resulting in distortion of upper abdominal anatomy. There is associated tortuosity and calcification of the abdominal aorta. A NG tube terminates within the stomach, which is distended with contrast proximally. There is very prominent distention of multiple loops of small bowel, with fluid distention more proximally and with fecal material being suggested more distally. The findings are suspicious for severe distal SBO. No abnormal colonic distention is seen. No intra-abdominal free air or generalized ascites is seen. There is extensive gas in the portal system. The uterus is presumed surgically absent.


1. Findings suspicious for high grade distal SBO. Surgical consult recommended.
2. No free air or generalized ascites.
3. Extensive gas in the portal system, of uncertain etiology.

Note: CT abdomen was initially read as pneumobilia (gas in the biliary system) which was later corrected. Pneumonilia is central in distribution as opposed to the peripheral distribution of the gas in the portal system seen in this patient.

A surgical consult was called urgenlty. The preoperative diagnosis of small bowel obstruction was confirmed during the laparotomy.The operation consisted of exploratory laparotomy and adhesiolysis.

Upon entering the abdomen, multiple loops of densely adherent and distended small bowel loops were encountered. By tracing the bowel down to the area of the ileocecal valve, the surgeon found dense adhesions which originated from the pelvis. These were lysed, after which the loops of bowel were then seen to decompress themselves in the distal bowel and into the cecum itself. The bowel appeared to be dusky but viable upon closer inspection. It was noted that the patient's mesentery pulsations were quite diminished, although no ischemia was noted.

After surgery, the patient improved and was discharged to the nursing home.

Final diagnosis

Small bowel obsctruction (SBO) secondary to adhesions, and gas in the portal system.

What did we learn from this case?

Bowel obstruction is on top of the list in elderly patients with abdominla pain and N/V, especially with a history of previous abdominal surgery.

CT abdomen is important in the diagnosis of SBO. Consult a surgeon early.

Comparison of small bowel obstruction (SBO) and LBO features :

Small bowel------------------------Large bowel

Bowel diameter (cm)
>3 and <--------------------------- >5

Position of loops

Number of loops

Bowel markings
(all the way across)-----------------(partially across)

Published: 02/12/2004
Updated: 10/03/2010


  1. did this have anything to do with the severe dextroscoliosis?

  2. Diagnostic: Billiar ileum (intestinal obstruction by gallbladder stone).

    The stone probably may be localized in the ileocecal valvule.

  3. Do you think that the removal of this woman's uterus allowed the bowels to loop?

  4. No, the mechanism is different. The hysterectomy did not cause SBO by allowing the "bowels to loop." The hysterectomy caused SBO by promoting the formation of adhesions which entrapped the bowel loops and this lead to SBO.

  5. I found this post while looking for information and pictures of a small bowel obstruction. I have been going through torture and pain for years. I got hit by a car which struck me directly in the stomach when I was seven years old. Due to that it caused many of issues in the abdomen which then resulted in many of adhesions all through my lower abdomen. I am a 28yr old female who cant live a normal life. I can not work nor can I have a child due to the accident when I was seven. In 2003 I had to have my left fallopian tube and my left ovary removed due to the adhesions and the car accident, but while the doctor was trying to remove them he put 3 cuts in my small bowel so he had to call in a bowel surgeon who tehn had to repair the holes in my small bowel. So because of the cuts put into my small bowel they had to remove some of the small bowel to fix and sew back together. Due to that mishap adhesions started forming around the small bowel that had been cut and sewn back together and because of the adhesions forming it resulted in me having a small bowel obstruction. In 2006 I was 23yrs old and had only weighed 87lbs due to the obstructions, I couldnt eat nor could I use the washroom because of those symptoms I lived with the most brutal torturous pain everyday. Finally after me suffering for months they had to do an emergency surgery. The surgery took 7hrs, 3 of those hours were used cutting the adhesions just to see the small bowel or any organ for that matter. The end result of that surgery ended up being that I lost multiple feet of my small bowel and I had lots of adhesions. After recovering from that surgery I felt great, I was able to live like a normal 23yr old female. I could eat again without having pain and throwing up, I started working and just all in all was able to "live my life" Unfortunatly within the past year or so I have started getting sick again, throwing up no energy so , so much pain and bloating with lots of air in my belly, but most of all I have lost alot of weight again. I am 28yrs old and I weigh 91 Lbs, not that its my choice because I feel awful about my weight. I cant eat hardly anything especially foods with the nutrition I need. I have gone back to my doctor who did tests and found the same old thing ADHESIONS... which again causes so much pain and obstructions of the small bowel, but because of the adhesions they dont want to operate as they say it will cause more damage and most likely will make my situation worse. I have had every single test imaginable done, I have seen a few different surgeons who have said the exact same thing" I do NOT want to open your stomache up unless it is an absolute emergency. Well I certainly dont look foward to haveing to have surgey especially such a high rish surgery but I just dont know how anyone thinks it is humaine to allow a person to have to live this way of life. So as it stands right now I am in pain every single day of my life, I cant eat very much and some of what I do eat causes so much pain and discomfort that I refrain from eating it again and all in all my being, my soul is just feeling defeated and I know I am a strong person because I have had many of hurdles I have had to jump through out my life but I jsut want to be able to just live you know the normal things that most people are able to do well have to do to live.(eat,work,and jsut be able to do normal things)I dont know exactly why I am writing this a part of me is maybe hoping someone can help with some sort of answer or maybe your going throughb the same thing and have some insight to share. well thanks to anyone who takes the time to read this and I if only I get one comment or suggestions on how or what I can do to better my situation than I am one step closer to what I am looking for. Thanks Again.

  6. Dr K reports this a C minus case