Diverticulitis is a common gastrointestinal condition characterized by the inflammation of abnormal pouches, called diverticula, that form in the wall of the large intestine. While generally confined to the colon, a severe episode can, in rare instances, lead to serious, life-threatening complications involving the liver. This occurs when infection from the colon spreads through the body’s vascular system. This article explains the anatomy of diverticulitis and details the specific mechanisms by which it can affect the liver.
The Anatomy of Diverticulitis
Diverticula are small, bulging pockets that protrude outward through weak spots in the muscular layer of the colon wall. The presence of these pockets is known as diverticulosis, which is common in adults over 50 and usually causes no symptoms.
The pouches most often develop in the sigmoid colon, located in the lower left abdomen. Diverticulitis occurs when one or more of these diverticula become inflamed or infected, often when small pieces of stool or bacteria get trapped inside.
Inflammation can range from mild to severe. In complicated cases, the infected pouch can rupture, creating a localized abscess or a perforation in the colon wall. This localized infection sets the stage for potential systemic spread if bacteria breach the body’s defense barriers.
How Diverticulitis Can Lead to Liver Involvement
Infection from the colon reaches the liver through the body’s circulatory network. Venous blood draining the large intestine flows into the portal venous system, which acts as a direct pathway, delivering blood from the digestive organs straight to the liver for filtering.
When severe diverticulitis breaches the intestinal wall, bacteria and septic material enter the small veins surrounding the inflamed colon. These bacteria-laden emboli travel into the mesenteric veins, which merge to form the large hepatic portal vein. This septic process within the veins of the portal system is known as pylephlebitis, or septic thrombophlebitis of the portal vein.
Pylephlebitis causes inflammation and clotting (thrombosis) within the portal vein. As these septic emboli are carried directly into the liver, they lodge in the smaller intrahepatic portal veins, leading to the formation of pyogenic (pus-forming) liver abscesses. The liver acts as a filter, trapping the infection that originated in the compromised colon.
Identifying Symptoms of Hepatic Complication
Recognizing when diverticulitis has progressed to involve the liver requires attention to signs that extend beyond typical lower abdominal pain, fever, and localized tenderness. The development of a hepatic complication introduces new, distinct symptoms suggesting a systemic infection.
The patient may experience persistent, high fever and chills. A common symptom of liver involvement is pain localized to the right upper quadrant of the abdomen, a marked shift from the lower-left quadrant pain usually associated with sigmoid diverticulitis.
Jaundice, characterized by the yellowing of the skin and the whites of the eyes, can develop due to impaired liver function. Other non-specific symptoms include unexplained weight loss, profound fatigue, and a general feeling of illness. These signs signal a need for immediate medical evaluation, as they suggest the infection has spread beyond the colon.
Medical Response and Treatment
The diagnosis of liver complications relies on laboratory tests and advanced imaging. Blood tests are used to detect elevated inflammatory markers, such as a high white blood cell count and C-reactive protein. Liver enzyme tests can also reveal abnormalities that point to liver distress or damage.
The definitive diagnosis of pylephlebitis and liver abscesses is achieved through imaging. A computed tomography (CT) scan with intravenous contrast is the gold standard, visualizing colon inflammation, portal vein thrombosis, and the extent of liver abscesses. Ultrasound with Doppler flow can confirm the absence of blood flow in the portal vein, consistent with pylephlebitis.
Treatment for these severe complications is aggressive and multi-modal. Broad-spectrum intravenous antibiotics are immediately initiated to target the bacterial infection, often including agents effective against intestinal flora. For defined liver abscesses, especially those larger than three centimeters, an interventional radiologist will perform a percutaneous drainage, using imaging guidance. In cases where the abscesses are numerous or the condition is complex, surgical drainage of the liver abscesses or resection of the severely diseased colon segment may be necessary.