October 23, 2026 by Dr. Arun S. Nair

A sudden pain in the lower left side of your stomach, along with fever and nausea, is easy to dismiss as simple gas or acidity. Many people do exactly that and wait for it to pass on their own. But if the pain keeps coming back, it could be diverticulitis, an inflammation of small pouches in the colon wall.

Most mild cases settle with rest, diet changes and medicines. In some people, though, it leads to complications like an abscess or a tear in the bowel, and surgery may become necessary. The hard part is knowing which situation you are in. Catching it early often makes the difference between simple treatment and an emergency.

This guide explains the symptoms, the warning signs and the stage at which surgery is considered. If you are looking for a Colorectal Surgeon in Thrissur, it will help you know what to ask and what to expect. It has been prepared with inputs from Dr. Arun S. Nair, who has 16 years of experience at Gastro Clinic. Read on to know which symptoms can wait and which cannot.

With age, small pouches can form in the wall of the large intestine (colon). These are called diverticula, and having them is known as diverticulosis. It is very common after 40, and most people never have any symptoms.

Diverticulitis happens when one or more of these pouches become inflamed or infected. It is part of what doctors call diverticular disease, and it usually affects the sigmoid colon on the lower left side (sigmoid diverticulitis).

Symptoms usually start mildly and build up over a day or two. Not everyone has all of them. Here is what each one means.

Pain in the lower left abdomen: This is usually the first and most common symptom, because the sigmoid colon sits on the lower left side. The pain is constant, not coming and going like gas cramps. It may be dull or sharp, gets worse on pressing or moving, and lasts for days, not just a few hours.
Fever and chills: Fever shows that your body is fighting an infection in the inflamed pouch. A high fever, or fever with shivering, may mean the infection is spreading, so see a doctor without delay.
Nausea or vomiting: An inflamed bowel slows down, which can cause nausea and loss of appetite. If you are vomiting repeatedly or cannot keep even water down, it needs urgent attention.
Bloating and gas: The belly feels full and swollen because gas and stool do not move normally. Unlike simple gas, the discomfort does not go away even after passing gas or stool.
Constipation or loose motions: Some people get constipated, others have loose motions, and some have both. A change in your usual bowel habit for more than a few days, along with belly pain, is an important clue.
Tenderness when pressed: The painful area is sore to touch. If the belly becomes hard and even slight movement causes severe pain, it can be a sign of a serious complication and needs emergency care.
Blood in the stool: Some people notice a small amount of bright red or maroon blood. Piles, infections or growths in the colon can also cause this, so it should always be checked by a Gastroenterologist in Thrissur. You may also notice tiredness, loss of appetite or burning while passing urine, which can happen when the inflamed colon irritates the bladder.

How is it different from gas or acidity? Gas and acidity settle within hours and rarely cause fever. In diverticulitis, the pain stays in one area for days, hurts on pressing and may come with fever or a change in bowel habit. If you notice this combination, get yourself checked instead of treating it at home.

Many people believe diverticulitis always causes left-sided pain. This is not always true. In Asian populations, the pouches are often found on the right side of the colon (cecal diverticulitis). The pain can then be mistaken for appendicitis. If you have right-sided pain with fever, do not assume it is just acidity. Get it examined.

Your doctor will examine your abdomen and may advise blood tests. A CT scan is the most reliable test to confirm diverticulitis and to check for complications. A colonoscopy is usually done a few weeks after you recover, to rule out other conditions of the large intestine. It is not done during an active attack.

Mild, uncomplicated cases are often managed with rest, a temporary liquid or low-fibre diet, pain relief and, in some cases, antibiotics. Please do not start antibiotics on your own. Your doctor will decide whether you need them.

Most people recover without any lasting problem. But in some, the inflammation spreads or keeps coming back, and this can lead to complications:

Abscess: A collection of pus forms near the inflamed pouch. Small abscesses may respond to antibiotics. Larger ones may need to be drained using a needle or tube guided by CT scan.
Perforation and peritonitis: The pouch bursts and infected contents leak into the abdominal cavity. This is a serious emergency.
Fistula: An abnormal connection forms between the colon and a nearby organ, such as the bladder or the vagina. It may cause repeated urine infections or air passing in urine.
Stricture or blockage: Repeated inflammation causes scarring, which narrows the colon. This can lead to bowel obstruction.
Bleeding: A blood vessel near a pouch may bleed, causing noticeable blood in the stool.

If you are wondering how diverticulosis turns into diverticulitis, the answer is usually inflammation or infection inside a pouch. The more often it happens, the higher the chance of scarring and complications.

Please go to the nearest hospital or call your doctor immediately if you notice any of these:

Severe abdominal pain that is getting worse
High fever with chills
Repeated vomiting, or being unable to keep fluids down
A hard, rigid abdomen
Blood in stool, or black stools
Not being able to pass stool or gas, along with a swollen belly
Air or stool in the urine
Feeling very weak, dizzy or confused

Many people ask what stools look like in diverticulitis. They may be loose or hard, and sometimes there is bright red or maroon blood. Any visible blood in stool should be checked by a doctor and never ignored.

The good news is that most people with diverticulitis do not need surgery. It is considered only when the risks of the disease are greater than the risks of the operation. Surgery is of two types: emergency and planned.

This is needed when a complication becomes life-threatening and cannot be controlled with medicines alone.

Perforation with peritonitis: The inflamed pouch bursts and pus or stool leaks into the abdomen. This causes severe pain, a hard belly and high fever, and needs urgent surgery.
A large abscess that cannot be drained with a needle: Small abscesses often settle with antibiotics, and bigger ones can be drained using a needle guided by a scan. Surgery is needed when the abscess cannot be reached or does not improve after drainage.
A complete blockage of the colon: Swelling or scarring can block the passage. You cannot pass stool or gas, and the belly becomes swollen with vomiting.
Severe infection (sepsis): The infection spreads into the blood and the person keeps getting worse despite antibiotics and other treatment.

Here there is no emergency, so you and your Colorectal Surgeon in Thrissur have time to plan. The operation is usually done a few weeks after an attack, once the inflammation has settled. It may be advised when:

Attacks keep coming back and affect your quality of life: Repeated pain, fever and hospital visits disturb your work and daily routine.
Symptoms do not settle after treatment: You continue to have pain or bowel problems even between attacks.
A fistula has formed: An abnormal connection between the colon and another organ, such as the bladder, rarely heals on its own.
The colon has become narrowed from scarring: This can cause repeated blockage, and sometimes it is difficult to rule out other growths in the colon without removing that part.
The person has a weak immune system: This includes people after a transplant or on long-term steroids. Their complications can be more severe, so surgery is considered earlier.

It is not based only on the number of attacks. Your surgeon will look at how severe your episodes were, your age, other health conditions and your own preferences. Some people have several mild attacks and do well with diet and lifestyle changes, while others need surgery after one serious attack.

A detailed discussion with a colorectal surgeon helps you decide at the right time, so that surgery is neither done too early nor delayed until it becomes an emergency.

The aim of surgery is to remove the diseased part of the colon, usually the sigmoid colon. This is known as colon resection or sigmoid colectomy. There are two main approaches.

Resection with primary anastomosis: The surgeon removes the affected segment and joins the two healthy ends of the colon back together. You pass stool normally afterwards. This is the preferred option when the abdomen is not badly infected.
Hartmann’s procedure: When there is severe infection or peritonitis, joining the bowel immediately may not be safe. In this case, the diseased part is removed and the upper end of the colon is brought out through the abdominal wall as a colostomy, which is a small opening where stool collects in a bag. Many patients have the colostomy reversed in a second surgery after a few months, once they have recovered.

Laparoscopic surgery for diverticulitis is done through small cuts using a camera and fine instruments. Compared to open surgery, it usually means:

Smaller scars
Less pain after the operation
Shorter hospital stay
Faster return to normal activities

Not everyone is suitable for the laparoscopic approach. In emergencies, or when the infection is extensive, an open operation may be safer. Your surgeon will choose the approach after assessing your scans and overall condition. If you are looking for a Laparoscopic Surgeon in Thrissur, it is worth asking whether your case is suitable for this approach.

Recovery varies from person to person, but here is a general idea of what to expect.

In hospital:

After laparoscopic surgery, many patients stay for a few days. Open surgery usually needs a longer stay.
You will be encouraged to walk early, which helps prevent clots and speeds up bowel recovery.
Liquids are started first, and solid food is added slowly.

At home:

Most people return to light daily activities within a few weeks. Full recovery often takes around 4 to 6 weeks, and a little longer after open surgery.
Avoid lifting heavy weights for the period your surgeon advises.
Take medicines as prescribed and attend your follow-up visits with your Laparoscopic Surgeon in Thrissur.

Diverticulitis diet after recovery:

During an attack or soon after surgery, you may be asked to take clear liquids, then a low-fibre diet.
Once you recover, a high-fibre diet is advised: fruits, vegetables, whole grains, pulses and oats. Increase fibre gradually and drink plenty of water.
The old advice to avoid nuts and seeds is not supported by current evidence, but check with your doctor if you have specific concerns.

Reducing the chance of future attacks:

Stay physically active and maintain a healthy weight
Quit smoking
Limit red meat and processed foods
Avoid regular use of painkillers like NSAIDs unless advised

Diverticulitis is common and, in most people, manageable. The key is to recognise the symptoms early, avoid self-medication and get the right evaluation. Surgery is needed only in selected situations, such as complications or repeated attacks, and modern laparoscopic techniques have made recovery much smoother.

If you have repeated lower abdominal pain, fever or changes in your bowel habits, do not wait for it to become severe. Consult an experienced Gastroenterologist in Thrissur for proper evaluation. At Gastro Clinic, Dr. Arun S. Nair, with 16 years of experience, can guide you on whether medicines, diet changes or surgery is the right path for you.

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What Is Diverticulitis?

Common Symptoms of Diverticulitis:

Pain on the right side is possible too:

How is it diagnosed?

Complications of Diverticulitis:

Warning Signs: When to Seek Emergency Care?

When Surgery May Be Needed?

1. Emergency surgery:

2. Planned (elective) surgery:

3. How is the decision made?

Types of Surgery for Diverticulitis:

Laparoscopic vs open surgery:

Recovery After Diverticulitis Surgery:

Conclusion:

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