Diverticular Disease

Overview

Diverticular disease describes problems caused by small bulging pouches, called diverticula, that form in the lining of the large intestine, most often in the lower left part of the colon. When these pouches are simply present without symptoms, the condition is called diverticulosis. When one or more become inflamed or infected, it is called diverticulitis, which can cause significant pain and illness. Some people also experience ongoing symptoms from the pouches without full-blown infection.

Diverticula become more common with age and are very widespread in older adults. Many people with diverticulosis never have problems, while others develop symptoms or complications. A diet rich in fiber and healthy bowel habits play a central role in managing the condition.

Symptoms

Symptoms depend on whether the pouches are simply present or are inflamed.

• Diverticulosis: Often causes no symptoms; some people have mild cramping, bloating, or irregular bowel habits.
• Diverticulitis: Causes pain, usually in the lower left abdomen, that may be steady and severe.
• Fever and chills with infection
• Nausea, vomiting, or loss of appetite
• Constipation or, less often, diarrhea
• Rectal bleeding, which can occur when a pouch bleeds

Sudden severe abdominal pain, high fever, or significant rectal bleeding needs prompt medical attention, as these can signal a complication.

Causes

Diverticula are thought to form where the colon wall is weakest, when pressure inside the bowel pushes the lining outward into small pouches. Several factors contribute.

• Low-fiber diet: Less fiber can mean harder stools and more straining, raising pressure in the colon.
• Aging: The colon wall naturally weakens over time.
• Changes in colon pressure and muscle function.

Diverticulitis develops when a pouch becomes blocked or irritated and bacteria multiply, leading to inflammation or infection. Genetics, gut bacteria, and other factors also appear to play a part.

Risk Factors

• Older age
• A diet low in fiber and high in red or processed meat
• Obesity
• Lack of physical activity
• Smoking
• Regular use of certain medicines, including some pain relievers (NSAIDs)

Diagnosis

Diverticulosis is often discovered by chance during tests done for other reasons, such as a routine colonoscopy. When diverticulitis is suspected, doctors combine a physical examination, where the lower left abdomen is often tender, with imaging and laboratory tests.

• CT scan of the abdomen: The main test to confirm diverticulitis, judge its severity, and check for complications such as an abscess or perforation.
• Colonoscopy: Usually done several weeks after an acute episode settles, to view the colon directly and rule out other causes such as inflammatory bowel disease or, rarely, cancer.
• Blood tests: Can show signs of infection or inflammation, such as a raised white blood cell count.
• Urine and other tests: May be used to exclude conditions that cause similar pain.

Treatment

Treatment depends on the severity of symptoms.

• Diverticulosis: Managed mainly with a high-fiber diet and plenty of fluids to keep stools soft.
• Mild diverticulitis: Often treated at home with rest, a temporary lighter diet, and, when needed, antibiotics prescribed by a doctor.
• More severe diverticulitis: May require hospital care with intravenous fluids and antibiotics.
• Surgery: Reserved for serious complications such as an abscess, perforation, blockage, or repeated severe attacks; it may involve removing the affected part of the colon.

Most people recover well. During an acute attack, doctors often advise resting the bowel with a clear-liquid or low-fiber diet at first, then gradually returning to a fiber-rich diet as symptoms settle. Drainage of an abscess through the skin, guided by imaging, can sometimes avoid the need for immediate surgery. Follow-up helps reduce the chance of future attacks.

Prevention

• Eat a diet rich in fiber from fruits, vegetables, whole grains, and legumes
• Drink plenty of fluids
• Stay physically active
• Maintain a healthy weight
• Avoid smoking
• Older guidance to avoid nuts and seeds is not supported by evidence for most people

When to See a Doctor

See a doctor for persistent abdominal pain, changes in bowel habits, or rectal bleeding. Seek urgent or emergency care if you have:

• Severe or worsening abdominal pain, especially on the lower left side
• High fever and chills
• Significant rectal bleeding or black stools
• Inability to pass stool or gas, with a swollen, tender abdomen

Related Topics

Frequently Asked Questions

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diverticular Disease.
2. Mayo Clinic. Diverticulitis.
3. MedlinePlus, U.S. National Library of Medicine. Diverticulosis and diverticulitis.