| disease | Blind Loop Syndrome |
| alias | Blindloop Syndrome |
Blind loop syndrome refers to a series of symptoms caused by colonic obstruction when a sexually transmitted disease cannot be removed. When the ileum and colon are bypassed and anastomosed, due to reverse peristaltic anastomosis, part of the intestinal contents enters the bypassed intestinal tract, leading to dilation of the bypassed intestine and other related issues.
bubble_chart Pathogenesis
Tumors and inflammation of the colon can cause narrowing of the intestinal lumen. When the diseased tissue cannot be removed due to systemic or local reasons, an ileocolonic bypass anastomosis is performed to address varying degrees of colonic obstruction. During the anastomosis, whether in a loop ileotransverse colostomy or an end-to-side ileosigmoidostomy, the ileum is not twisted or crossed but directly anastomosed to the colon, resulting in an antiperistaltic anastomosis. This means that part of the contents from the proximal ileum first enter the bypassed colon before moving into the distal colon. In cases of incomplete obstruction, some contents pass through the narrowed segment into the bypassed proximal colon, leading to a series of pathological changes.
bubble_chart Pathological Changes
Patients with blind loop syndrome experience a situation where a portion of the contents from the proximal ileum enters the bypassed distal colon, causing this segment of the colon to generate peristalsis and propel most of the contents into the distal colon. Another portion of the contents passes through the narrowed area into the temporarily placed proximal colon. This portion of the contents has two pathways for elimination: one is to move with peristalsis through the narrowing and re-enter the distal colon; the other is to move against peristalsis from the bypassed distal ileum into the distal colon.
The above-described movement of ileal contents repeatedly stimulates the bypassed intestinal segment and leads to the accumulation of contents, resulting in the dilation of the bypassed colon, especially near the proximal side of the narrowing. Over time, the colon wall thickens, forming a mass. When peristalsis passes through the narrowed area or occurs, it may cause abdominal pain, and in severe cases, lead to symptoms such as nausea and vomiting. The purpose of a bypass anastomosis is to allow the diseased location to rest, reduce stimulation to tumors and slow their growth, or promote the early resolution of inflammation and other pathological conditions. If the anastomosis is oriented against the direction of peristalsis, tumor growth may accelerate, and inflammation may heal more slowly.bubble_chart Clinical Manifestations
1. Abdominal pain
Accompanied by nausea and vomiting, symptoms can occur after the recovery of intestinal peristalsis post-surgery. The pain may manifest as abdominal distending pain or dull pain, and in severe cases, colicky pain may occur.
2. Abdominal distension and fullness
Corresponding discomfort and bloating in the proximal area of the original intestinal obstruction lesion may also present with borborygmus.
3. Sign
Primarily includes signs at the site of the original intestinal obstruction lesion, such as masses and tenderness. Additionally, proximal to the intestinal obstruction lesion, signs of intestinal dilation such as visible intestinal loops and peristaltic waves may be observed, along with palpable sausage-like masses and dilated intestinal segments.
bubble_chart Auxiliary Examination
1. X-ray examination
Plain abdominal film shows dilated intestinal loops (proximal to the obstructive lesion). Small intestine contrast: Reveals barium retrograde flow from the anastomotic site into the bypassed intestinal segment, with partial retrograde passage through the stenotic area into the proximal bypassed loop. The barium is then propelled distally beyond the anastomosis by peristalsis or refluxed back to the anastomotic site by antiperistalsis.2. B-mode ultrasound
Can detect the original colonic lesion and its proximally dilated intestinal segments.
bubble_chart Treatment Measures
I. General Treatment
1. Fast for 3-5 days and observe changes in the condition.
2. Administer intravenous fluids to correct typical edema and electrolyte imbalances.
3. Provide antibiotics to prevent infection.
II. Surgical Treatment
If conservative treatment is ineffective, reverse the peristaltic direction of the colonic anastomosis to normal peristalsis. For loop anastomosis, it can be dismantled and then re-sutured in the opposite direction. For double-end anastomosis, dismantle the anastomosis between the proximal ileum and the colon, close the colonic anastomosis, and perform an ileocolonic anastomosis on the colon approximately 5 cm distal to the anastomosis between the distal ileum and the colon.
Surgical errors causing abdominal pain, abdominal distension, and fullness can affect eating, especially in patients with intestinal cancer, who may rapidly deteriorate and die.
During ileocolonic bypass anastomosis, it is essential to align with peristalsis, ensuring the direction matches that of the large intestine. Additionally, 2–3 reinforcing sutures should be placed at the proximal end of the anastomosis in the seromuscular layer to enhance peristaltic consistency. If performing a double-end anastomosis between the ileum and colon—where the distal ileum is anastomosed to the proximal colon and the proximal ileum to the distal colon—the two anastomotic sites should be spaced approximately 5 cm apart to prevent reflux.
If the lesion does not cause complete intestinal obstruction, sealing the terminal ileum and performing an end-to-side anastomosis of the proximal ileum to the colon proximal to the lesion is a significant error. As the lesion progresses to complete obstruction, the secretions from the intestinal mucosa between the sealed end and the lesion will increase, gradually dilating and potentially rupturing, leading to peritonitis. This constitutes a surgical error and warrants heightened vigilance.1. Adhesive intestinal obstruction
There is a history of ileocolic anastomosis surgery, presenting with abdominal pain, abdominal distension and fullness, vomiting, and cessation of flatus and defecation. Abdominal plain films show small intestine air-fluid levels, which can aid in differentiation.
2. Anastomotic stenosis
If there is stenosis at the anastomosis between the proximal ileum and the large intestine, symptoms of varying degrees of intestinal obstruction such as abdominal pain and abdominal distension and fullness may occur. However, abdominal plain films show no displaced or dilated bowel, and small intestine contrast studies indicate difficulty in barium passage through the anastomosis, making the distinction straightforward.
