Difference Between Colitis and Diverticulitis

Colitis and diverticulitis are two inflammatory diseases of the colon that are difficult to be diagnosed solely based on the clinical features. The inflammation of the colon is known as colitis. Diverticulitis is the inflammation of the diverticula in the colon. As seen from the definitions, colitis is a condition that occurs in the colon whereas diverticulitis is a condition that takes place in the diverticula. This is the main difference between colitis and diverticulitis.

CONTENTS

1. Overview and Key Difference
2. What is Colitis
3. What is Diverticulitis
4. Similarities Between Colitis and Diverticulitis
5. Side by Side Comparison – Colitis vs Diverticulitis in Tabular Form
6. Summary

What is Colitis?

The inflammation of the colon is known as colitis. Clinical features of this condition vary according to the underlying pathology.

Main Causes

• Ulcerative colitis
• Crohn’s disease
• Antibiotic-associated colitis
• Infective colitis
• Ischemic colitis

Crohn’s Disease

Crohn’s disease is an inflammatory bowel disease characterized by the transmural inflammation of the colonic mucosa. Usually, only some regions of the colon are inflamed, giving rise to skip lesions rather than a continuous involvement.

Clinical Picture

Diarrhea

Diarrhea in Crohn’s disease is due to the excessive secretion of the fluids and the impaired absorption of fluids by the inflamed bowel mucosa. In addition, the malabsorption of bile salts by the inflamed terminal ileum also contributes to the aggravation of diarrhea.

Fibrostenotic Disease

The obstruction of the gastrointestinal tract due to small bowel strictures or colonic strictures can give rise to symptoms such as abdominal pain, constipation, nausea, and vomiting.

Fistulizing Disease

The transmural inflammation of the GIT can be the cause of sinus tracts, serosal penetration, and fistulae such as enteroenteric fistulae. The penetration of the bowel by the inflammatory lesions leads to the leakage of colonic substances into the peritoneal cavity, resulting in peritonitis and other associated complications.

Local complications of Crohn’s disease

• Watery diarrhea due to the stimulatory effects on colonic water and electrolyte absorption
• The reduced concentration of bile acids interrupts the absorption of fat thus resulting in steatorrhea
• Long-term steatorrhea can lead to osteoporosis, malnutrition and clotting abnormalities
• Formation of gallstones
• Nephrolithiasis (formation of kidney stones)
• Vitamin B12 malabsorption

Crohn’s disease increases the risk of colon cancers, lymphomas and squamous cell carcinomas of the anus.

Morphology

• Macroscopy

Mostly the right side of the colon is affected by the Crohn’s disease. There is a segmental distribution of the lesions. Usually, the rectum is spared.

• Microscopy

There is a transmural involvement with the occurrence of fissures and noncaseating granulomas.

Diagnosis

The clinical history and examination play a vital role in the diagnosis of CD.

Endoscopy reveals the presence of the presence of aphthous ulcers that give rise to a cobblestone appearance. Abdominal and pelvic scanning can be used to identify any abscesses.

Management

There is no definite cure for the Crohn’s disease. The aim of treatment is the suppression of inflammatory processes that give rise to the clinically manifested signs and symptoms.

• Anti-inflammatory drugs – Corticosteroids such as prednisolone and Aminosalicylates
• Immune system suppressors such as azathioprine and biological agents such as infliximab
• Antibiotics
• Analgesics
• Antidiarrheals
• Iron and vitamin B12 supplements

In some cases, surgical removal of the damaged parts of the colon is required.

Ulcerative Colitis

Ulcerative colitis is an inflammatory disease of the rectum extending proximally to variable distance. Women are more likely to be affected by this condition than men.

Clinical Features

• Blood and mucus diarrhea
• Cramp-like abdominal pain
• Per rectal bleeding
• In some cases, there can be toxemia, fever and severe bleeding.

 Investigations

• Sigmoidoscopy
• Colonoscopy
• Barium enema
• Examination of the stools reveals the presence of blood and pus

  Figure 01: Histopathological image of the active stage of ulcerative colitis

Complications

Local complications

• Toxic dilatation
• Hemorrhage
• Stricture
• Malignant changes
• Perianal diseases such as anal fissures and anal fistulae.

General Complications

• Toxemia
• Anemia
• Weight loss
• Arthritis and uveitis
• Dermatological manifestations such as pyoderma gangrenosum
• Primary sclerosing cholangitis

Management

Medical Management

A high protein diet with vitamin supplements and iron is prescribed. Blood transfusion may be required if the patient shows clinical signs of severe anemia. Loperamide is usually given to control diarrhea. The administration of corticosteroids as per rectal infusions induces remission in an acute attack. Immunosuppressors such as infliximab are required to control more severe attacks of ulcerative colitis.

Surgical Management

Surgical intervention is indicated only in the following situations.

• Fulminating disease not responding to medical treatments
• Chronic disease not responding to medical treatments
• Prophylaxis against malignant changes
• In the occasions where the patient presents with the complications mentioned above.

What is Diverticulitis?

Diverticulitis is the inflammation of the diverticula in the colon. These diverticula can be of either congenital or acquired origin.

An inflamed diverticulum can give rise to the following complications.

• The diverticulum can perforate into the peritoneum resulting in peritonitis. Pericolic abscesses can be formed if it penetrates the pericolic tissues. Its perforation into any other adjacent structure is most likely to end up with the occurrence of fistula.
• The chronic inflammation associated with diverticulitis leads to fibrosis of the inflamed tissues giving rise to obstructive symptoms such as constipation.
• The erosion into blood vessels results in internal hemorrhages.

Clinical Features

Acute Diverticulitis

This condition is known as the left-sided appendicitis because of the characteristic pain of acute onset that originates in the low central region of the abdomen and gradually shifts to the left iliac fossa. There can be other nonspecific symptoms such as nausea, vomiting, and local tenderness.

Chronic Diverticular Disease

This mimics the clinical features of a colonic carcinoma.

• Change in bowel habits
• Vomiting, abdominal bloating, colicky abdominal pain, and constipation due to the obstruction of the large bowel.
• Blood and mucus per rectum

Investigations

• CT is the most appropriate investigation to identify diverticulitis in its acute stage by excluding other possible diagnoses.
• Sigmoidoscopy
• Colonoscopy
• Barium enema

Treatment

Acute Diverticulitis:

Conservative management is recommended for treating a patient diagnosed with acute diverticulitis. The patient is kept on a fluid diet and antibiotics such as metronidazole and ciprofloxacin.

• Pericolic abscesses are diagnosed by CT. Percutaneous drainage of these abscesses is essential to avoid any future complications.
• In case of a ruptured abscess giving rise to peritonitis, the pus should be removed from the peritoneal cavity by laparoscopic lavage and drainage.
• When there is a diverticulitis associated obstruction in the colon, laparotomy is required to establish the diagnosis.

Chronic Diverticular Disease

This condition is managed conservatively if the symptoms are mild and the diagnosis has been confirmed through investigations. Usually, a lubricant laxative and high fiber containing diet are prescribed. When the symptoms are severe, and the possibility of a colonic carcinoma cannot be excluded, laparotomy and resection of the sigmoid colon are carried out.

What are the Similarities Between Colitis and Diverticulitis?

• Both are inflammatory processes.
• Abdominal pain is observed as a clinical symptom in both conditions.

What is the Difference Between Colitis and Diverticulitis?

Summary – Colitis vs Diverticulitis

Diverticulitis is the inflammation of the diverticula in the colon. The inflammation of the colon is known as colitis. The main difference between colitis and diverticulitis is that they occur in two separate sites.

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References:

1.”Ulcerative colitis (2) endoscopic biopsy” By User:KGH – Own work (CC BY-SA 3.0) via Commons Wikimedia
2.”Intraoperative view of sigmoid diverticulitis” By Anpol42 – Own work (CC BY-SA 4.0) via Commons Wikimedia