Causes and Risk Factors
Diverticula form when pressure inside the colon pushes the inner lining outward through weak points in the muscle wall. Several factors make diverticulosis, and flares of diverticulitis, more likely:- Age: The colon wall naturally weakens over time, so pouches become more common in later decades of life.
- Low-fiber diet: A diet low in fiber produces harder stool and higher pressure inside the colon.
- Excess weight and inactivity: Both are associated with a higher risk of diverticulitis episodes.
- Smoking: Tobacco use increases the risk of complicated diverticulitis.
- Certain medications: Regular use of NSAIDs such as ibuprofen has been linked to a higher risk of diverticular complications.
- Family history: Genetics play a meaningful role in who develops diverticular disease.
Symptoms
Diverticulosis alone usually causes no symptoms at all, and many people learn they have it only after a colonoscopy or CT scan done for another reason. Occasional cramping, bloating, or changes in bowel habits can occur and may overlap with symptoms of irritable bowel syndrome. Diverticulitis is different and typically causes:- Abdominal pain: Usually steady pain in the lower left side of the abdomen that may build over a day or two.
- Fever and chills: Signs that inflammation or infection is present.
- Nausea and loss of appetite: Sometimes with vomiting.
- A change in bowel habits: Constipation is common; some people have diarrhea.
Diagnosis
When diverticulitis is suspected, a CT scan of the abdomen is the most reliable way to confirm the diagnosis and check for complications such as an abscess or perforation. Blood tests can show signs of infection. After an episode fully resolves, a colonoscopy is often recommended — if one has not been done recently — to examine the colon and rule out other conditions, including colon polyps and inflammatory bowel disease such as Crohn's disease.Treatment
Treatment depends on how severe the episode is.- Mild, uncomplicated diverticulitis: Many episodes can be managed at home with rest, a temporary liquid or low-residue diet, and close follow-up. Antibiotics such as amoxicillin-clavulanate, or ciprofloxacin combined with metronidazole, are prescribed when needed.
- Complicated diverticulitis: High fever, an abscess, or perforation requires hospital care with intravenous antibiotics and sometimes drainage or surgery.
- Prevention between episodes: A high-fiber diet, plenty of fluids, regular exercise, and maintaining a healthy weight all lower the risk of recurrence. Contrary to older advice, nuts, seeds, and popcorn do not need to be avoided.
- Recurrent disease: After multiple significant episodes, elective surgery to remove the affected segment of colon may be discussed.
When to Seek Immediate Care
Go to the emergency department for severe or rapidly worsening abdominal pain, a high fever, persistent vomiting, or significant rectal bleeding. These can signal a complication that needs urgent treatment. Diverticula can also bleed painlessly on their own; sudden passage of a large amount of red or maroon blood from the rectum should always be treated as an emergency, even without pain. Most people with diverticulosis never develop diverticulitis, and flares that do occur are very manageable with prompt attention. The internal-medicine team at Zimmer Medical Group can help you treat an episode and build a prevention plan.Living With Diverticular Disease
Most of what patients were told about diverticular disease a generation ago has been revised: antibiotics are no longer automatic, seeds and nuts were never the problem, and surgery is no longer decided by counting attacks. Knowing the current approach avoids both needless treatment and a dangerous delay.
Not every episode needs antibiotics
A mild, uncomplicated episode confirmed on CT in an otherwise healthy person can be managed with rest, a short period of liquids, pain control, and a follow-up call within a couple of days; trials show antibiotics do not speed recovery in that setting. Amoxicillin-clavulanate, or ciprofloxacin with metronidazole, is prescribed when there is fever, a weakened immune system, other significant illness, an abscess, or no improvement after a few days. Pain not settling by the third day is re-imaged rather than given a second course. Our modern diverticulitis care article explains the shift.
Painkillers, steroids, and what raises perforation risk
NSAIDs such as ibuprofen and opioid painkillers both increase the risk of perforation and are avoided during an episode; acetaminophen is used instead. Long-term steroids and immune-suppressing drugs carry the same risk and lower the threshold for antibiotics and hospital care. Obesity, smoking, and inactivity raise the chance of recurrence, and each is worth addressing between episodes.
The colonoscopy after the first attack
Six to eight weeks after a first CT-confirmed episode, once inflammation has settled, a colonoscopy is done unless one was completed recently, because a small number of cases that look like diverticulitis on CT are actually colon cancer, and because colon polyps are found often at that age. Our colon cancer screening options article covers what happens if colonoscopy is not possible. Ongoing cramping and altered bowel habit after recovery is more often irritable bowel syndrome overlapping with diverticulosis than smoldering infection, and it is treated as such.
Fiber, water, and the bowel between attacks
A diet high in fiber from vegetables, fruit, beans, and whole grains lowers the risk of recurrence and treats the chronic constipation that raises pressure in the colon; fiber is increased gradually with plenty of fluid, and a daily osmotic laxative such as polyethylene glycol is added when diet is not enough. Florida heat hardens stool quickly, as our staying hydrated article explains. Probiotics, mesalamine, and rifaximin have not been shown to prevent attacks reliably.
When surgery is discussed, and when it is an emergency
Elective removal of the affected colon segment is no longer triggered by a set number of attacks; it is considered when episodes are frequent enough to disrupt life, after a complicated episode with abscess or fistula, or when a stricture narrows the bowel, and it is a personal decision made with a colorectal surgeon. Severe pain with a rigid abdomen, high fever with shaking chills, persistent vomiting, or brisk rectal bleeding needs the emergency department the same day. Our gastrointestinal team manages episodes and arranges the follow-up colonoscopy. The NIDDK and MedlinePlus publish patient guidance on diet, treatment, and complications.
If you have had diverticulitis and never had the follow-up colonoscopy, or keep needing antibiotic courses, schedule a visit.