Last updated date: 12-Apr-2023

Medically Reviewed By

Medically reviewed by

Dr. Lavrinenko Oleg

Medically reviewed by

Dr. Hakkou Karima

Originally Written in English

All you need to know about Diverticulitis


    The large intestine (colon) of the human body could often present some small and bubbly bulges. These small expansions on the colon are called diverticula.


    Diverticulitis Definition

    Diverticulitis is a serious diverticular condition that can develop in one's colon over time. Diverticulitis is defined by an inflammatory condition that begins within the diverticulum (occlusion by a fecalith and microperforation) or at the diverticulum's neck (ischemia or mechanical injury).

    Inflammation with microperforation is characterized by a peridiverticular mesenteric inflammatory response that can develop to pericolic and mural phlegmonous infiltration, fistulization, sealed perforation, abscess, free perforation, peritonitis, and a stenosing inflammatory sigmoid tumor. Bleeding is another (distinctive) consequence of diverticular illness.

    The presence (absence) of perforation, which is identified by the presence of air, fistulas, or abscesses, is the proven difference between serious and simple diverticulitis.

    While the risk of diverticulosis and hospitalization for diverticulitis rises with age, the relative likelihood of having diverticulitis falls. Furthermore, the requirement for hospitalization and elective surgery increased most rapidly among the younger (45-year-old) group.


    Diverticulitis Causes

    Though it is not exactly known what causes it, diverticulitis appears as a result of the weakening of the colon's walls in time. Usually, diverticulitis appears in men over 40 years old, while others develop it only when they are over 75 years old.

    Researchers link diverticulitis with age, lifestyle, diet, and genetics. They consider that the weakening process of the large intestine's walls is stimulated by muscular contractions. Both feces and food by-products could be the reasons for higher pressure within the colon. The unhealthier food you are eating, the stronger the muscular contractions and the pressure. The pressure within the colon is the main reason that forces the inner mucosa to penetrate via small blood vessels into the colon wall and create bulges (diverticula). As the intracolonic pressure rises, more rows of diverticula could occur.

    Despite the dichotomy of occurrence between Western and Asian civilizations (both North American and European civilizations are half affected by diverticulitis, while the occurrence within the Asians is considerably lower) diverticulitis is a very uncommon disease among vegetarians. This validates the idea that eating healthy and maintaining an active lifestyle could protect you from diverticulitis.


    Risk Factors

    Studies show that there are numerous risk factors that lead to diverticulitis. The most important ones among them are:

    • Smoking;
    • Red meat;
    • Low dietary fiber;
    • Overweight or obesity;
    • Sedentary life;
    • Drugs (steroids and opiates).


    Diverticulitis vs Diverticulosis

    Diverticulitis and diverticulosis are different conditions of the colon and together they make up the diverticular disease category. The common point between these two conditions is the presence of diverticula.

    Diverticula is an outpouching formed in the wall of the colon due to pressure from muscular contractions. Normally, the dimensions of diverticula range from the size of a pea to much larger. The location of the diverticula is often in the sigmoid colon, in the lower-left side of the abdomen.

    Diverticulosis is diagnosed when it has been noticed the presence of diverticula within the colon. It is a very common condition of the colon, about 50% of those over 50 years old have it, and most of the persons over 80 years old. Diverticulosis does not have any symptoms and it does not bother you in any way. It is usually discovered by chance, while medical investigations search for other conditions in the abdomen area. However, diverticulosis could lead to diverticulitis. About 30% of those that have diverticulosis develop diverticulitis.

    Diverticulitis is the inflammation and infection of one or more diverticula. Diverticulitis could be painful. The pain location of diverticulitis is in the lower-left side of the abdomen, where diverticula are located. Diverticulitis usually ignites symptoms like fever, nausea, vomiting, constipation, or diarrhea.


    Is Diverticulitis Serious?

    Diverticulitis is a serious condition that could be a lifelong condition. Moreover, it can get very severe and if left untreated, diverticulitis could be very dangerous eventually.


    Is Diverticulitis Painful?

    Normally, diverticulitis pain consists of cramp-like pain in the lower-left part of the abdomen. Other pains could appear due to the other symptoms, such as vomiting, fever, constipation, or diarrhea.


    Is Diverticulitis Contagious?

    As diverticulitis is a result of an unhealthy lifestyle and diet, it is not contagious. Fortunately, diverticulitis isn’t cancerous either. 


    Is Diverticulitis Hereditary?

    Scientists have found out that if you have family members that were diagnosed with diverticulitis you are likely to develop the disease as well. Furthermore, scientists have also found that if one of your family members (ancestors) has been diagnosed with diverticulitis before turning 50 years old, you are very likely to develop it, too.

    While this is a significant finding, it is hardly surprising because in most intestinal conditions, heredity is one of the risk factors. So naturally, for those individuals who have or have had close family members suffering from diverticulitis, the risk of developing the condition is higher. However, although diverticulosis can be hereditary, it’s important to note that the leading cause of the disease is not family history or genes. A significant factor that increases the risk of diverticulitis, apart from age, is pressure on the walls of the colon. It’s caused due to straining during bowel movements, which in turn is caused by inadequate consumption of dietary fiber or even chronic dehydration. Due to insufficient fiber or inadequate hydration, it can be challenging for the colon to effectively form bulk and expel it, which may eventually lead to diverticulosis. 

    It’s helpful to know this significant fact so one can take preventative measures to develop a potential safeguard against the condition. Increasing fiber in the diet and ensuring adequate water consumption are two ways patients can help prevent the onslaught of this disease. Especially individuals who are genetically predisposed to diverticulosis may consider adopting these practices to minimize their risk of developing the condition. Also it’d be worthwhile to point out that not all patients with diverticulosis end up contracting diverticulitis. 



    The pathophysiology of diverticulitis is characterized by hypertrophy (and elastosis) with growing breadth of the circular muscle layer, with diverticula emerging at natural gaps associated with arteriole penetration feeding the (sub-)mucosal layers.

    Diverticulitis generally begins in a single diverticulum, which is the source of the most discomfort when compressed, and inflammation may spread to other diverticula in the area, i.e. advancement in a longitudinal direction.

    Inflammation normally begins in the diverticulum's outpouched mucosa, making it endoscopically inconspicuous unless inflammation moves back to the mucosa from outside the wall, or a rupture in the diverticular neck caused by the passage ('birth') of a fecalith causes diverticulitis.

    As a result, the central question for cross-sectional imaging is not only whether or not an abscess/perforation is present, but also whether the aforementioned morphological criteria of diverticulitis are present, or whether, for example, segmental colonic inflammation involves only a diverticula-bearing segment.

    Diverticulitis Symptoms

    The symptoms of diverticulitis could vary, depending on the severity level of the disease. First of all, diverticulitis pain is usually felt in the lower left part of the abdomen, but it can also occur on the right side.

    In case of diverticulitis, besides the pain in the abdomen, other symptoms can also occur, such as:

    • High fever that could be accompanied by chills;
    • Nausea and/or vomiting;
    • Constipation or diarrhea – these are the least common symptoms of diverticulitis.

    Moreover, during a diverticulitis flare-up, the stools can often present blood or there could be bleedings from the rectum.

    Fiver, vomiting and stools with blood might represent signs of serious complications of diverticulitis.

    Signs of sigmoidal diverticulitis are also described by the term ‘left-sided appendicitis’ with the following symptoms: 

    1. spontaneous pain in the left lower quadrant  
    2. inflammatory reaction (CRP, WBC, temperature) 
    3. local guarding upon palpation. 

    However, since this triad is variable, time-dependent, and unspecific, it may arouse the suspicion of diverticulitis without fulfilling modern diagnostic criteria. Clinical judgment has a sensitivity of 65-70 percent based on history and physical examination as well as laboratory results, a value that is pretty constant across research.


    Differentiating Symptoms of Diverticulitis from Other Colonic Diseases 


    Acute Appendicitis

    One of the most prevalent grounds for surgical consultation by emergency room physicians is right lower quadrant abdominal discomfort. Acute appendicitis is the most common cause of this discomfort. Several additional disorders, however, appear with identical symptoms and necessitate differential diagnosis.

    Colonic diverticulitis is one of several disorders that can cause pain in the right lower quadrant. Although colonic diverticulitis is usually left-sided, it is uncommon on the right, where the process tends to develop in the cecum or ascending colon. Patients between the ages of 20 and 40 are more likely to develop right-sided colonic diverticulitis. This lower age of onset contrasts sharply with the normal older individuals who develop left-sided colonic diverticulitis.

    Acute appendicitis is also prevalent in young children with pain in the right lower quadrant. As a result, in the right, it is frequently difficult to distinguish between right-sided colonic diverticulitis and acute appendicitis. As a result of these factors, 80 percent of patients with right-sided colonic diverticulitis are misdiagnosed with acute appendicitis during the pre-op examination. Only 3-6 percent of these individuals are accurately diagnosed prior to surgery.


    Colon Infections

    Microorganisms that have found their way into your gut, which is part of your digestive system, cause bowel infections. The following are some of the most frequent symptoms of a gastrointestinal infection:

    • diarrhea
    • nausea
    • vomiting
    • crampy abdominal pain
    • fever
    • headache


    Colon Cancer

    Diverticulosis and colorectal neoplasia have comparable epidemiological patterns and risk factors in Western nations, and occurrences rise with age. However, the evidence for a link between diverticulosis and colorectal neoplasia is mixed.

    Diverticulosis is not connected with an increased risk of advanced colorectal neoplasia, according to research. Although diverticulosis was linked to an elevated risk of polyps and adenomas, the risk did not rise in screening groups. CT scans are frequently used to confirm a diagnosis of probable colon cancer or colonic diverticulitis.


    Crohn's Disease (CD)

    Diverticulitis and inflammatory bowel disease (IBD) are both intestinal inflammatory disorders that cause higher morbidity and death in patients. Crohn's disease (CD) is characterized by transmural inflammation of the gastrointestinal system. It is characterized by mucosal layer inflammation that begins in the rectum and can progress proximally across the colon. Crohn disease is generally distinguished from diverticulitis by perianal disease and endoscopic inspection of cobble-stoning, aphthous ulcerations, and biopsies indicating granulomas.



    Diverticulitis is an inflammation of the diverticula that often manifests as stomach discomfort, nausea, vomiting, rectal bleeding, diarrhea, and fever. When the inflammatory process affects the ascending colon diverticula, the illness poses a clinical challenge since it is readily confused with other acute abdominal crises.

    Right-sided diverticulitis (RSD) might be confused with cholecystitis, appendicitis, or epiploic appendagitis. The difference between these disorders and RSD is critical since the latter is conservatively treated and abscess development is uncommon.

    Within the range of available investigations, the Ultrasounds is the first imaging study modality conducted in patients who come with abdominal discomfort. It can safely rule out cholecystitis and detect numerous abdominal disorders, including epiploic appendagitis (EA), appendicitis, colitis, neoplastic lesion, and Crohn's disease, each of which has distinct sonographic features. Furthermore, gallstones are more prevalent in female patients, whether they have a diverticular disease or not.


    Escherichia Coli

    People frequently associate E.coli with food poisoning, and while this type of bacteria can produce food poisoning symptoms, it can also lead to more dangerous ailments such as pneumonia and urinary tract infections.

    In fact, E.coli bacteria are thought to cause the most majority of UTIs (up to 95 percent). This is because, while it's in the intestines, it's not far from the urinary tract, and because they're all connected, it can easily make its way over there and start causing problems.


    How is Diverticulitis Diagnosed?

    Diverticulitis how to diagnose?

    In a patient with left lower quadrant pain, the diagnosis of (sigmoid) diverticulitis requires both proof of an inflammatory response (C-reactive protein (CRP) > white blood cell (WBC) count and erythrocyte sedimentation rate (ESR)) and localization of inflammation at the site of a diverticulum using an imaging method, such as US or CT.

    Usually, diverticulitis is diagnosed by performing a CT scan of the abdomen and pelvis. It is highly indicated that the patient drinks a form of oral contrast before performing a CT scan, in order to highlight the intestinal tract and make it more visible to doctors. The accuracy of diagnosing diverticulitis using CT scanners is between 94% and 99%. Therefore, CT scans are usually used just to confirm the diagnosis. Another way of diagnosing diverticulitis is by colonoscopy, but it is avoided in case of acute diverticulitis as it might lead to perforation of the colon.


    Diverticulitis Treatment

    If you have already been diagnosed with diverticulosis, you should consume mostly foods that contain high levels of fiber, in order to prevent the occurrence of diverticulitis.

    But in case you do get diverticulitis, you should know that the treatment has more components.

    • Diet
    • Medical treatments 
    • Surgery


    Diverticulitis Foods

    In order to treat diverticulitis, diet is one of the most important aspects. As eating unhealthy foods is one of the main causes of this disease, eating healthier foods will help in reducing symptoms and long-term damages.

    According to specialists, consuming food that consists of high levels of fiber could protect you from diverticulosis and diverticulitis. As an example, the incidence of diverticulitis and diverticulosis is considerably lower on the Asian continent, where people tend to eat foods that are rich in fiber. This is quite in opposition with Western civilizations, whose daily diets are based on low-fiber foods, and where the incidence is considerably higher.

    In order to maintain the diverticular situation under control, you should follow a diet that has high fiber content. But if you happen to have a diverticulitis crisis, you should follow a low fiber diet, until you are fully recovered. In some situations, it is recommended to follow a liquid-only diet, in order to protect the affected area.  After the diverticulitis flare-up starts to fade out, you can slowly start to eat normally, but your diet ought to include about 30g of fiber per day.

    The best sources of fiber that comply with most of the diets are:

    • Fruits (both fresh and dried);
    • Vegetables;
    • Cereals.

    If your daily diet does not cover the necessary amount of fiber, you can add to it supplements that will fulfill the lack of fiber and help enhance gut function and prevent constipation. Normally, these supplements that cover the missing amount of fiber that you need can be found in pharmacies and they come as a powder that needs to be mixed with water, in order to be ready for consumption. The fiber supplements that are mostly prescribed are psyllium (Metamucil) or methylcellulose (Citrucel). Usually, fiber supplements are consumed one to three times a day.

    Do not start following a diet without consulting with your doctor or nutritionist in this regard. Without the advice of a specialist, the diet you follow might improve the symptoms of your diverticulitis, but worsen other health conditions. Therefore, a specialist's expertise and recommendation are always needed, in order to avoid unwanted health difficulties.

    In case that you are experiencing diverticulitis, your specialist might lead you to a liquid diverticulitis diet that will go hand in hand with your treatment. So, in order to improve your symptoms and your state of overall health, any doctor would recommend you to eat cautiously, in order to protect the affected area of the colon. Therefore, the ailments that doctors will most likely recommend you at the beginning of the diverticulitis cure would be:

    • Water (at least 2 liters a day and if you are an active person you should definitely drink more than that);
    • Natural and fresh juices;
    • Soups (cream soups - like tomato soup, broccoli soup, etc.);

    The recovery of diverticulitis often starts with low-fiber foods. So, in the early stages of the recovery, the doctor will recommend you to eat foods like white bread, fish, poultry, eggs or even dairy products. While you have already started to recover, the doctor will softly slip higher-fiber foods, until you can normally eat high fiber foods. After recovering from diverticulitis, it is very important to eat high-fiber foods, as they are the ones responsible for healthy shaping the stools, in such a way that they pass easily through the large intestine and reduce the pressure from the digestive tract.


    High Fiber Diet Target

    Studies show that females that are no older than 51 years old should eat at least 25 grams of fiber per day, while men no older than the same age should try to eat at least 38 grams of fiber per day. Those over 51 years old should try to eat at least 25 grams of fiber per day if they are women, and at least 30 grams of fiber per day if they are men.

    If you need advice on what to include in your high-fiber diet, you should consider the following:

    • Whole-grain foods, like pasta, bread, or cereals;
    • Beans;
    • Fruits and vegetables.

    Moreover, while following a strictly high-fiber diet, it is recommended to exercise regularly, in order to better propel the waste through the digestive system.

    During the eruption of diverticulitis, doctors usually recommend resting, treating the disease with antibiotics and a diverticulitis clear liquid diet.

    A clear liquid diet is recommended only when the severity level of diverticulitis is high, even if it needs surgery or not.

    During diverticulitis flare-ups, the clear liquid diet consists of:

    • Water;
    • Pulp free juices;
    • Broth
    • Popsicles (as dessert).

    But if you have a mild diverticulitis flare-up or you already are on a recovery pace, the doctor will advise you on a low-fiber diet. Regarding a low-fiber diet, the daily intake amounts of fiber should be limited, only between 8 and 12 grams, but it depends on how affected the colon was.

    The most recommended foods to eat while recovering from a diverticulitis flare-up are:

    • Potatoes;
    • Eggs;
    • Meat - but it has to be shredded, in order to be tender;
    • Seafood;
    • Fruits - only some, such as peaches or pears or you can eat applesauce or ripe bananas. Usually, the fruit's high levels of insoluble fiber are found in the skin.
    • Dairy - it is recommended to eat Greek yogurt or Cottage cheese as these are high in protein and calcium and are fiber-free. Moreover, their softness is easily accepted by your affected intestine.

    Your doctor will gradually raise the amount of fiber intake in your diet. The process could take from days to weeks, depending on how severe the flare-up was. This way, constipation and bloating will be avoided.


    Diverticulitis Foods to Avoid

    During a diverticulitis flare-up, it is best to consume soft and tender foods, in order to avoid the inflammation of the diverticula.

    Moreover, during a diverticulitis flare-up, you should avoid eating foods that are rich in fiber. For example, you should avoid:

    • Grain: pasta, bread, etc.;
    • Beans;
    • Fruits;
    • Vegetables.


    Diverticulitis Medications

    In terms of drugs, diverticulitis is easy to treat at home.

    The treatment for diverticulitis is usually based on pain management – usually, with paracetamol, which is used to ameliorate the symptoms and, in order to treat the infection, doctors will prescribe antibiotics.

    It is very important to know that if you are suffering from diverticulitis, you must not take aspirin or ibuprofen-based medicines as they might cause stomach troubles.

    If you also have symptoms such as constipation or diarrhea, the doctor should prescribe you a transit regulator.

    If you have a more serious case of diverticulitis, you may need to be hospitalized. Considering the severity of the disease, the antibiotics might come as injections and intravenous drip could replace any eating or drinking.  Moreover, if paracetamol is not able to manage the pain, health care professionals will be able to prescribe you a more powerful painkiller.


    Diverticulitis Surgery

    Due to diverticulitis complications, in some cases, surgery might be needed in order to treat the disease.

    Surgery for diverticulitis is only considered and done in situations such as:

    • Diverticulitis with an abscess – In this case, surgical intervention is needed only if the liquid of the abscess has not been fully collected with a catheter. Surgery is performed, in order to completely clean the affected area;
    • Diverticulitis with perforation – this scenario represents the situation of having a perforation into your colon that makes it possible for pus and stools to spill into the abdominal cavity, resulting in peritonitis, which is life-threatening. The purpose of the surgery in this scenario is to clean the infected area and to remove the affected area of the large intestine;
    • Diverticulitis with blockages or strictures – this type of diverticulitis infection results from previous infections of the large intestine whose effects are of narrowing it or even blocking it. In case the colon gets blocked, surgery is mandatory to clear up the situation and liberate the colon;
    • Diverticulitis with fistula – A fistula represents an abscess that creates an abnormal connection between organs and they do not close naturally. A fistula that appears in the colon could reach the bladder, vagina, uterus, another part of the colon, or even the skin. Surgery is needed in this scenario, to close the fistula;
    • Diverticulosis with rectal bleeding – This type of diverticulosis is caused by the burst of a blood vessel in the approximate area of the diverticula and it might need surgical intervention, in case the bleeding does not stop naturally or by treatment. The mild bleedings usually stop naturally, while only 20% of the diverticulosis with rectal bleeding cases need treatment;
    • Chronic diverticulitis whose symptoms have not been improved by treatment or by respecting a diet that has a high amount of fiber.

    Depending on the severity and how spread the disease is, your doctor will decide which kind of surgery is needed to improve the symptoms and heal the affected area. Therefore, the whole surgery process could be done in only one surgery or divided into two or more surgeries.

    The surgery for diverticulitis is not necessarily made in an open procedure mode (large incision), it can also be made by minimally invasive laparoscopic procedure (small incision). It is up to the in-charge surgeon to decide which kind of surgery it will be performed.

    Moreover, depending on the severity of the disease, some of the patients that need surgical intervention will also need to get a colectomy. Colectomy means that the affected portion of your colon will be removed and it will be followed by a colostomy, which could be temporary or permanent. Colostomy means that a channel will be created from the end of the healthy colon to the surface of the skin, in order to collect the waste into a special bag, named a colostomy bag. In case of temporary need for colostomy, the bag will be used for about a couple of months, until the large intestine heals. When the colon is healed, the large intestine is reconnected to the rectum and the colostomy bag is finally removed.

    You should discuss with your surgeon before the surgical intervention about the risks, complications, and what to expect after the procedure is done.


    Differential Diagnoses

    Clinically, sigmoid diverticulitis can produce symptoms not just in the left lower quadrant, but also in the right lower quadrant and anyplace in the lower abdomen. This spectrum is also extended to the right upper abdomen by right-sided diverticulitis.

    Thus, inflammatory and non-inflammatory disorders of the gastrointestinal tract and urogenital system, as well as vascular diseases, are the common differential diagnoses of diverticular disease/diverticulitis.

    • Cholangitis
    • Cholecystitis
    • Chronic mesenteric ischemia
    • Constipation
    • Enterovesical fistula
    • Gynecological pain
    • Inflammatory bowel disease
    • Intestinal perforation
    • Irritable bowel syndrome (IBS)
    • Large-bowel obstruction



    The prognosis of diverticulitis patients is determined by their age at presentation, the existence of comorbidities, and the severity of the disease. In general, younger persons have greater morbidity since they are unaware they have the condition and frequently arrive late. Furthermore, immunocompromised people have a significant morbidity and death rate. 



    Complications occur in around 15% of individuals with acute diverticulitis. Recurrent bouts of diverticulitis affect between 20% and 50% of individuals. Multiple episodes do not appear to directly raise the likelihood of problems. It may raise the likelihood of fibrosis, resulting in the creation of strictures and consequent blockage.

    Around 20% of individuals will develop persistent stomach discomfort as a result of irritable bowel syndrome or chronic low-grade diverticulitis. For symptom relief, these individuals may be recommended for elective colectomy. Diverticulitis complications include:

    • Pelvic abscess
    • Intestinal perforation
    • Bowel fistula
    • Peritonitis
    • Bowel obstruction
    • Sepsis
    • Bleeding per rectum


    Diverticulitis Care

    After treatment, the flare-up of diverticulitis is healed. This does not mean that the diverticula disappears. The presence of diverticula, diverticulosis, is a lifelong condition.

    Statistics show that diverticulitis is possible to reoccur after mild initial flare-ups, where no surgical intervention has been made. In very rare cases, diverticulitis flare-up could recur in patients that had a sigmoid colon resection. Moreover, it is reported that about 20% to 35% of those that have had diverticulitis do have recurrent attacks of diverticulitis. Also, about 36% of persons have abdominal symptoms after the first diverticulitis flare-up.



    Acute diverticulitis is an inflammation caused by a diverticulum micro-perforation. A diverticulum is a pouch-like protrusion of the colon wall. Diverticulitis can occur in 10% to 25% of persons with diverticulosis.

    Diverticulitis can be simple, difficult, or both. There are no problems associated with uncomplicated diverticulitis. Complicated diverticulitis is characterized by the development of an abscess, a fistula, intestinal blockage, or a frank perforation that causes peritonitis.

    Diverticulitis was once known and treated as predominantly a surgical ailment, but it is now a medically controlled phenomenon, even at its most severe stage.