Diverticulosis: Symptoms, Types, Causes and Treatment

Diverticulosis is a common gastrointestinal condition, especially prevalent in older adults, characterized by the formation of small pouches, or diverticula, in the wall of the colon. While many people with diverticulosis are asymptomatic, a significant number can develop uncomfortable symptoms or even serious complications. Understanding the spectrum of symptoms, the different types of diverticulosis, its underlying causes, and the latest treatment options can empower patients and caregivers to better manage this condition.

Symptoms of Diverticulosis

Diverticulosis often flies under the radar, with most individuals experiencing no symptoms at all. However, for those who do develop symptoms, these can range from mild discomfort to more persistent or even severe gastrointestinal disturbances. Recognizing the spectrum of possible symptoms is crucial for timely diagnosis and management.

Symptom	Description	Prevalence/Risk Group	Source(s)
Abdominal Pain	Usually left lower quadrant, persistent	More common in SUDD and older adults	1,4,5,8
Changes in Bowel Habits	Diarrhea, loose stools, increased frequency	Across all age groups, especially >60	4,5
Constipation	Less common than previously thought	Not strongly associated	11
Bloating/Cramping	Non-specific, may mimic IBS	Variable	2,3,17
Diverticular Bleeding	Sudden, painless rectal bleeding	Subset of patients	3,9
Asymptomatic	No symptoms	Majority of patients	3,14

Table 1: Key Symptoms of Diverticulosis

Abdominal Pain

One of the most recognized symptoms in symptomatic diverticulosis, especially in those with Symptomatic Uncomplicated Diverticular Disease (SUDD), is persistent pain in the left lower abdomen. This pain may last for at least 24 hours and can be moderate to severe in intensity. It's often the best distinguishing feature between SUDD and other disorders like irritable bowel syndrome (IBS) with similar symptoms but without visible diverticula on imaging or colonoscopy 1,8.

Changes in Bowel Habits

Contrary to older beliefs, loose stools and increased stool frequency are more commonly associated with diverticulosis than constipation. Several studies observed that individuals with diverticulosis are more likely to report diarrhea, urgency, and mucus in the stool, especially in those over 60 years old 4,5. While constipation has been historically linked to diverticulosis, recent evidence challenges this association 11.

Bloating and Cramping

Some patients may experience vague symptoms such as bloating, cramping, or a sense of abdominal fullness. These symptoms can overlap with those of IBS and are more likely in people with chronic symptomatic disease 2,17.

Diverticular Bleeding

A small proportion of individuals can develop sudden, painless rectal bleeding, which occurs when a small blood vessel within a diverticulum ruptures. This is a significant but less common complication 3,9.

Asymptomatic Presentation

Importantly, most people with diverticulosis remain entirely asymptomatic and may only discover the condition incidentally during routine colonoscopy or imaging for unrelated reasons 3,14.

Types of Diverticulosis

Diverticulosis is not a one-size-fits-all diagnosis. It encompasses a spectrum of presentations and can affect different parts of the gastrointestinal tract, each with its own clinical features and potential complications.

Type	Key Features	Site/Population	Source(s)
Colonic (Sigmoid)	Most common, often asymptomatic	Older adults, Western countries	3,7,14
Symptomatic Uncomplicated Diverticular Disease (SUDD)	Chronic pain, no inflammation	Subset with symptoms	1,2,17
Diverticulitis	Inflammation, acute symptoms	1–4% of patients with diverticulosis	8,9,13
Diverticular Bleeding	Sudden rectal bleeding	Variable	3,9
Jejunal/Small Bowel	Rare, may cause malabsorption	Elderly, systemic disease	6

Table 2: Major Types of Diverticulosis

Colonic Diverticulosis

The vast majority of diverticula form in the colon, especially in the sigmoid section. This form is most prevalent in older adults and in Western countries, likely due to dietary and lifestyle factors. Many people with colonic diverticulosis are asymptomatic, but some may develop chronic symptoms or complications 3,7,14.

Symptomatic Uncomplicated Diverticular Disease (SUDD)

SUDD is characterized by chronic left lower abdominal pain without signs of acute inflammation or infection. It is distinct from diverticulitis and IBS, although symptoms can overlap. SUDD may also include altered bowel habits, such as loose stools or increased frequency 1,2,17.

Diverticulitis

A minority of patients with diverticulosis (about 1–4%) develop diverticulitis, an acute inflammatory complication. This presents with sudden, usually severe abdominal pain, fever, and other systemic symptoms. Diverticulitis can be further classified as uncomplicated or complicated, depending on the presence of abscess, perforation, or other sequelae 8,9,13.

Diverticular Bleeding

Some patients experience diverticular bleeding, which typically presents as painless rectal bleeding. While it can be alarming, it usually resolves spontaneously. However, recurrent or severe bleeding may require medical or surgical intervention 3,9.

Jejunal and Small Bowel Diverticulosis

Diverticulosis can also occur in the small intestine, most commonly in the jejunum. This is rare and usually seen in older individuals, sometimes associated with systemic diseases like progressive systemic sclerosis. Symptoms may include malabsorption, chronic diarrhea, or intestinal pseudo-obstruction 6.

Causes of Diverticulosis

The underlying causes of diverticulosis are complex and multifactorial. While the classic explanation focused on low dietary fiber, newer research suggests a broader interplay of genetic, environmental, and structural factors.

Cause	Mechanism/Description	Importance	Source(s)
Age	Weakening of bowel wall over time	Major risk factor	4,8,14
Genetics	Neuromuscular/connective tissue defects	Significant heritability	12,16
Diet/Lifestyle	Low fiber, high red meat, inactivity	Contributing factors	8,10,14
Colonic Motility	Abnormal muscular contractions	Potential mechanism	7,12,14,17
Obesity/Smoking	Increases risk	Modifiable	8,13,16
Medications	NSAIDs, steroids, opiates	Increased risk	8,13
Microbiome	Altered gut flora, low-grade inflammation	Possible roles	2,16,14
Not Constipation	Constipation not a clear cause	Debunked myth	11

Table 3: Contributing Causes of Diverticulosis

Age

The prevalence of diverticulosis increases dramatically with age, affecting over half of individuals above 60 years old. Age-related changes in the connective tissue and muscle layers of the colon predispose the bowel wall to the formation of diverticula 4,8,14.

Genetics

Genetic factors play a significant role, with recent genome-wide association studies identifying multiple risk loci related to neuromuscular and connective tissue function in the colon. About 50% of the susceptibility to diverticular disease is thought to be heritable 12,16.

Diet and Lifestyle

Although the traditional hypothesis emphasized a low-fiber diet as the leading cause, recent research has challenged this view. While a Western diet high in red meat and low in fiber, along with physical inactivity and obesity, are associated with increased risk of complications like diverticulitis, they may not directly cause the formation of diverticula themselves 8,10,14. Notably, constipation is not linked to a higher risk of diverticulosis and, in some cases, may even be protective 11.

Colonic Motility

Abnormalities in colonic motility—such as increased pressure or uncoordinated muscular contractions—can promote the formation of diverticula, especially in the sigmoid colon. These changes may be related to both genetic predisposition and environmental factors 7,12,14,17.

Medications and Other Risk Factors

Certain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and opiates, are associated with increased risk of diverticular complications 8,13. Smoking and obesity are also significant and modifiable risk factors 8,13,16.

Gut Microbiome and Inflammation

Emerging research suggests that disturbances in the intestinal microbiome and low-grade chronic inflammation may contribute to symptom development and progression to diverticular disease, although they may not cause diverticulosis outright 2,16,14. However, population-based studies have not found consistent evidence of mucosal inflammation in uncomplicated diverticulosis 5.

Treatment of Diverticulosis

Managing diverticulosis depends on whether a patient is asymptomatic, has chronic symptoms, or develops complications like diverticulitis or bleeding. Recent advances have shifted treatment strategies toward more individualized and less invasive approaches.

Treatment	Purpose/Use	Current Evidence/Trends	Source(s)
High-Fiber Diet	Traditionally recommended	May help symptoms, unclear prevention	13,17,18
Antibiotics (Acute)	For diverticulitis/complications	May not be needed in mild cases	8,15,16
Probiotics	Symptom relief in SUDD	Emerging, not definitive	2,14,17
Mesalamine	Symptom relief in SUDD	Some benefit, unclear prevention	2,14,17
Rifaximin	Non-absorbable antibiotic for SUDD	Promising for symptoms	14,17
Surgery	For complications (perforation, abscess, recurrent bleeding)	Reserved for select cases	8,13,16
Avoid NSAIDs	Reduce risk of complications	Strong recommendation	8,13

Table 4: Treatments for Diverticulosis and Its Complications

Asymptomatic Diverticulosis

For the majority with no symptoms, no specific treatment is required. A balanced diet high in fiber is often recommended, but its role in preventing diverticulosis is unclear. However, it may help regulate bowel habits and prevent complications 13,17,18.

Symptomatic Uncomplicated Diverticular Disease (SUDD)

In patients with chronic symptoms but no acute inflammation, high-fiber diets, probiotics, rifaximin, and mesalamine have shown some benefit in reducing abdominal pain and improving quality of life. However, evidence is still emerging, and these therapies may not prevent progression or complications 2,14,17.

Acute Diverticulitis

The mainstay of treatment for uncomplicated diverticulitis has traditionally been antibiotics, but recent large clinical trials show that many patients can recover without antibiotics, especially in mild to moderate cases 8,15,16. Hospitalization, intravenous antibiotics, and surgery are reserved for those with severe or complicated disease, such as abscess, perforation, or fistula formation.

Surgical Interventions

Surgery is now reserved for patients with recurrent severe complications, persistent symptoms not responsive to medical therapy, or life-threatening complications such as perforation with peritonitis or uncontrolled bleeding. Elective surgery is no longer routinely recommended after a single episode of diverticulitis 8,13,16.

Lifestyle and Risk Factor Modification

• Avoiding NSAIDs, corticosteroids, and opiates when possible can reduce the risk of complications.
• Maintaining a healthy weight, quitting smoking, and engaging in regular physical activity are strongly recommended to lower the risk of diverticular disease and its complications 8,13,16.

Conclusion

Diverticulosis is a multifaceted condition with a broad spectrum of presentations, causes, and management strategies. Key points to remember include:

• Most patients are asymptomatic, but symptoms can include left lower abdominal pain, loose stools, and, rarely, bleeding.
• Types include colonic and small bowel diverticulosis, with complications such as diverticulitis and bleeding occurring in a minority.
• Causes are multifactorial, with aging, genetics, lifestyle, and colonic motility playing key roles—constipation is not a primary cause.
• Treatment is individualized, ranging from dietary and lifestyle modifications for asymptomatic or mild cases to antibiotics and surgery for severe complications. Recent evidence supports less aggressive use of antibiotics in uncomplicated diverticulitis.

By understanding the nuances of diverticulosis, both patients and healthcare providers can work together to optimize care, minimize complications, and improve quality of life.