An internal hernia occurs when an organ, most often the small intestine, protrudes through an opening within the abdominal cavity. Unlike more familiar external hernias, there is no visible bulge on the outside of the body because the herniation happens internally. The organ pushes through a natural or surgically created aperture, and the lack of external signs can make identification more challenging.
Causes and Risk Factors
Internal hernias have two primary origins: acquired and congenital. Acquired hernias, the more common type, develop as a consequence of previous abdominal surgery. Surgical procedures can create new spaces or defects in the mesentery, the tissue that holds the intestines in place, through which bowel can slip. This is particularly prevalent after bariatric (weight-loss) surgery, like the Roux-en-Y gastric bypass.
Laparoscopic surgeries are associated with a higher incidence of internal hernias compared to open procedures. This is because laparoscopy results in fewer internal scars, known as adhesions, which would otherwise hold the intestines in place. Significant weight loss following bariatric surgery also contributes to the risk by enlarging potential hernia spaces. Abdominal trauma or chronic inflammation from conditions like Crohn’s disease can also create defects.
Congenital internal hernias are much rarer and result from developmental anomalies present at birth. These occur when the lining of the abdominal cavity fails to form correctly, leaving natural pockets or gaps. These defects can exist for years without causing issues, but if a loop of intestine wanders into one of these congenital pockets, it can become trapped.
Recognizing the Symptoms
The symptoms of an internal hernia are often difficult to pinpoint because they can be vague, intermittent, and mimic other gastrointestinal problems. Many individuals experience recurring episodes of crampy or dull abdominal pain that is difficult to localize. This discomfort frequently appears or worsens after eating and can be accompanied by bloating, nausea, and occasional vomiting.
These symptoms can persist for months or even years, coming and going without a clear pattern, which makes a prompt diagnosis difficult. This intermittent nature can be frustrating and often leads to extensive testing for other conditions before an internal hernia is considered. The unpredictable pattern is a hallmark of this condition.
A more serious situation arises when an internal hernia presents acutely. This occurs when the trapped loop of bowel becomes completely blocked (an obstruction) or twisted. In this scenario, the symptoms are sudden and severe, constituting a medical emergency. The person may experience intense abdominal pain, persistent vomiting, an inability to pass gas or have a bowel movement, and abdominal distension.
The Diagnostic Process
Diagnosing an internal hernia can be a challenge because the symptoms are non-specific. The most reliable diagnostic tool is a computed tomography (CT) scan of the abdomen. This imaging test provides detailed cross-sectional pictures of the abdominal cavity, allowing radiologists to look for specific signs.
On a CT scan, one common finding is a cluster of dilated small bowel loops in an unusual location. Another significant sign is the “whirl sign,” where the mesenteric blood vessels and fat appear twisted or swirled. Even with advanced imaging, a CT scan is not always definitive, and the findings can be subtle, especially if the hernia has temporarily reduced itself.
If imaging is inconclusive but symptoms strongly suggest a hernia, a definitive diagnosis may be made through surgery. A diagnostic laparoscopy is a minimally invasive procedure where a surgeon inserts a camera into the abdomen to directly visualize the organs. This allows for direct inspection and confirmation of a hernia, which can be repaired during the same procedure.
Surgical Treatment and Recovery
The definitive treatment for a symptomatic internal hernia is surgery. The procedure has two main objectives: to return the herniated organ to its correct position, a step known as reduction, and to close the internal defect to prevent it from happening again. This is done with sutures, permanently closing the gap in the mesentery or other tissue.
Surgery is often performed with urgency to prevent a serious complication known as strangulation. Strangulation occurs when the herniated loop of bowel becomes so tightly constricted that its blood supply is cut off. This can cause the tissue to die, a condition called necrosis, which can lead to life-threatening infection. The risk of strangulation is a reason why surgical repair is recommended even for patients with intermittent symptoms.
The surgical approach can be either laparoscopic or open. Laparoscopic surgery, using small incisions and a camera, is preferred due to its association with less pain, a shorter hospital stay, and a quicker recovery. In emergency situations, such as a complete bowel obstruction, an open surgery with a larger incision may be necessary for better access.
Recovery after the operation varies depending on the type of surgery performed and the patient’s condition. For a planned laparoscopic repair, patients may go home within a day or two and return to normal activities within a few weeks. If an emergency open surgery was required, especially if a portion of the intestine had to be removed, the recovery period will be longer and more involved.