Acute Diverticulitis

In contrast with diverticulitis, acute diverticulitis can go through periods of worsening or improving inflammation. Diverticulitis develops when pouches in the intestines, known as diverticula, become inflamed and press into the intestinal wall. Sometimes, they can push through, causing perforation or abscesses (a collection of pus). Like chronic diverticulitis, the acute version can be mild or severe depending on whether a person develops complications.

This article discusses the symptoms, causes, and risk factors associated with acute diverticulitis. 

Woman with abdominal pain

Catherine McQueen / Getty Images

Acute Diverticulitis Symptoms 

Acute diverticulitis doesn’t always present with symptoms, so some people may have it without realizing it. However, when signs do develop, they can include:  

  • Mild or severe pain in the lower left side of the abdomen
  • Gastrointestinal issues such as constipation or diarrhea
  • Fevers and chills
  • Nausea
  • Vomiting
  • Loss of appetite
  • Painful urination
  • Low blood pressure
  • Tachycardia (a heartbeat over 100 beats per minute)
  • Abdominal tenderness
  • A mass in the abdomen
  • Abdomen that is swollen outward

What Does Acute Diverticulitis Pain Feel Like?

The pain associated with diverticulitis is often sharp and cramping. It usually comes on suddenly and is severe, but it can also develop slowly and feel milder at first, worsening over several days.

Causes and Risk Factors

The direct cause of acute diverticulitis isn’t well known. However, research surrounding the disease has found many risk factors at play. Some of those include:

  • Genetics: Certain genes may make a person susceptible to developing acute diverticulitis.
  • Lifestyle: Low-fiber diets, lack of exercise, and smoking can contribute to diverticulitis.
  • Medications: Regular use of non-steroidal anti-inflammatories (NSAIDs) and steroids may also increase a person’s disease risk.
  • Pre-existing health conditions: Obesity is a known risk factor.
  • Gut Imbalances: The gut is home to different gut bacteria meant to keep the body healthy. When those become imbalanced, it may contribute to diverticulitis.

Ongoing Research and the Cause of Acute Diverticulitis

Medical researchers continue to search for information that could help determine a cause or other risk factors. Some they have found that may play a role include:

  • Immune system dysfunction
  • Issues with the nerves, tissues, or muscles within the colon
  • Bacteria or stool being caught in pouches within your intestines


Diagnosing acute diverticulitis relies on several tools. First, healthcare providers will need to perform a physical exam and collect a health history to understand the symptoms a person is experiencing and their overall health and lifestyle.

After collecting the information from the physical exam, healthcare providers will likely order several tests to get a better look inside the abdomen. Some possible tests include:

When used together, these tests not only diagnose acute diverticulitis but also rule out other possible conditions that can present the same way.

Similar Conditions

The symptoms of acute diverticulitis are similar to other conditions that affect the abdomen. Some possible health afflictions that could present similarly to acute diverticulitis include:

Why Prompt Testing Is So Important

Because acute diverticulitis and conditions that present similar can become medical emergencies, it’s vital to get the correct diagnosis as soon as possible if you experience the symptoms mentioned above.


There are several complications associated with diverticulitis. While not everyone will experience them, they are a risk. Adverse events that can occur because of the acute disease include:

  • Perforation
  • Abscess
  • Pylephlebitis, which is inflammation of an abdominal vein known as the portal vein
  • Bowel obstruction
  • Gastrointestinal bleeding
  • Fistulas

While these complications can be treated, they can also be life-threatening.

Complicated vs. Uncomplicated Diverticulitis

When a person develops more severe health issues because of diverticulitis, it is referred to as complicated diverticulitis. In contrast, uncomplicated diverticulitis describes localized inflammation that does not cause further complications, such as the ones mentioned above.


Most people with acute diverticulitis can be treated outside the hospital using antibiotics and a liquid diet. This will give the intestines a break while the antibiotics help to heal them.

Acute and uncomplicated diverticulitis may require hospitalization if:

  • A person cannot tolerate oral antibiotics
  • Their symptoms are severe
  • A person has a high fever
  • They have existing comorbidities that increase the risk of adverse complications

If a person has signs of complicated acute diverticulitis, they must be admitted to the hospital and treated there so that healthcare providers can keep an eye on them. While in the hospital, they will receive medication, fluids, and nutrients through an IV (a direct line into the bloodstream).

In the worst cases, people will have to undergo surgery. Surgery for acute diverticulitis is designed to drain or rinse out the infection or abscess or remove the part of the intestines affected by the disease.

How Long Does It Last?

With proper treatment based on a person’s symptoms, the time it takes to recover varies. Typically, people who have undergone outpatient treatment can expect to feel better within a week. Those that stayed in the hospital may see improvements in their symptoms in as little as two to four days.

When to Seek Care

While acute diverticulitis isn’t always severe and can go away on its own within a week, it’s important to note that the symptoms associated with the disease can worsen, leading to life-threatening complications.

Because of that, if you experience any of the symptoms mentioned above, contact your healthcare provider or go to the emergency room. Any number of diseases can cause severe abdominal pain that doesn’t go away, so it’s important to rule out the wrong ones and get diagnosed with the right one so you can begin prompt treatment.


Acute diverticulitis is a form of condition that comes and goes. For example, a person may develop acute diverticulitis once or twice and never again. The symptoms associated with the condition can vary depending on the person. The most notable is abdominal pain which tends to stem from the lower right side of the abdomen.

People experiencing acute diverticulitis must undergo several tests and exams to reach a proper diagnosis. By doing so quickly, they can get treated before any severe or life-threatening complications arise. Acute diverticulitis isn't always serious and can be treated effectively in a relatively short amount of time.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.