Hemorrhagic proctocolitis is a clinical syndrome defined by inflammation and bleeding of the inner lining of the rectum and colon. The colon and rectum make up the large intestine, which is responsible for absorbing water from stool and storing it before a bowel movement. When the lining of this organ becomes inflamed, it loses its ability to absorb water, leading to diarrhea. The inflammation also makes the tissue fragile and causes the formation of small sores, or ulcers, which can bleed easily, resulting in blood and mucus in the stool.

A helpful analogy is to think of the lining of your colon as a smooth, healthy wallpaper.

• In hemorrhagic proctocolitis, this wallpaper has become severely inflamed, raw, and damaged, like a severe sunburn on the inside.
• This raw surface begins to weep fluid and bleed easily.
• The critical medical question is always: What is causing the damage to the wallpaper? Is it a temporary “vandal” like a bacterial infection that can be eliminated? Or is it a chronic “internal problem,” like a faulty sprinkler system (the immune system) that is constantly damaging the wall?

Answering this question is the entire goal of the diagnostic process.

In my experience, patients with hemorrhagic proctocolitis often present to the ER frightened by the sudden appearance of bloody diarrhea, especially when accompanied by abdominal pain.

Hemorrhagic proctocolitis results from any condition that causes significant inflammation and ulceration of the colorectal mucosa. The potential causes are broad and can be grouped into several main categories.

1. Infectious Colitis

In many cases, especially those with a sudden onset, the cause is an infection. Several different pathogens are known to invade the lining of the colon and cause bloody diarrhea (dysentery).

• Bacteria: Common bacterial causes include Shigella, Salmonella, Campylobacter, and certain strains of E. coli (like EHEC O157:H7). An infection with Clostridioides difficile (C. diff), often occurring after a course of antibiotics, can also cause severe inflammation and bleeding.
• Parasites: An infection with the parasite Entamoeba histolytica, a condition known as amoebiasis, is a well-known cause of bloody diarrhea, particularly in tropical and subtropical regions.

2. Inflammatory Bowel Disease (IBD)

IBD is a group of chronic autoimmune diseases that are a leading cause of long-term hemorrhagic proctocolitis.

• Ulcerative Colitis (UC): This is the classic cause. In UC, the immune system launches a sustained attack on the lining of the large intestine, always starting in the rectum and progressing upward in a continuous fashion.
• Crohn’s Disease: While Crohn’s disease can affect any part of the digestive tract, when it specifically affects the colon (Crohn’s colitis), it can also cause inflammation, ulcers, and bloody diarrhea similar to UC.

3. Ischemic Colitis

This condition occurs when there is a sudden, temporary loss of blood flow to a segment of the colon. The lack of oxygen damages the tissue, causing inflammation, pain, and bleeding. This is seen more commonly in older adults with underlying cardiovascular disease.

4. Radiation Proctocolitis

This is a side effect of radiation therapy directed at the pelvis to treat cancers such as prostate, cervical, or rectal cancer. The radiation can cause both acute and chronic inflammation and damage to the rectum and colon, leading to bleeding.

Clinically, I’ve seen it most commonly caused by ischemia (especially in older adults), bacterial infections like E. coli or Shigella, and flare-ups of ulcerative colitis.

A person develops the symptoms of hemorrhagic proctocolitis by contracting or developing one of the underlying causative conditions. It is not contagious itself, but some of its causes are.

• Infectious colitis is acquired by consuming food or water contaminated with the specific bacteria or parasite.
• Inflammatory Bowel Disease (IBD) is not contagious. It develops in individuals with a genetic predisposition, likely after exposure to an unknown environmental trigger that causes their immune system to become dysregulated.
• Ischemic colitis develops in individuals with risk factors for vascular disease, such as old age, high blood pressure, diabetes, and smoking.
• Radiation proctocolitis is a direct result of undergoing radiation therapy.

In my experience, patients often develop it after events that compromise blood flow to the colon, such as dehydration, hypotension, or vascular disease.

The core symptoms that define the syndrome are directly related to the inflammation of the rectum and colon.

The primary signs and symptoms include:

• Bloody Diarrhea: This is the hallmark symptom. The frequency can range from a few to many bowel movements per day, containing varying amounts of liquid stool, blood, and mucus.
• Urgency: A sudden, strong, and often desperate need to rush to the bathroom.
• Tenesmus: A distressing and often painful feeling of needing to have a bowel movement even though the bowel is already empty. This is caused by severe inflammation in the rectum.
• Abdominal Pain and Cramping: This is often located in the lower left quadrant of the abdomen.

Other associated symptoms can help a doctor differentiate the cause. For example, a very high fever and sudden onset point more toward an infectious cause, while a long history of intermittent symptoms and associated joint pain might point more toward IBD.

Clinically, I look for left-sided abdominal tenderness, signs of dehydration, and lab abnormalities like elevated white cell count or C-reactive protein, which may indicate infection or inflammation.

Because the treatments for the various causes are completely different, getting an accurate diagnosis is absolutely essential. The diagnostic process is a stepwise investigation managed by a gastroenterologist.

Step 1: Ruling Out Infection

The first and most important step is to rule out an infectious cause. This is because giving immunosuppressive medication (for IBD) to someone with an active infection can be very dangerous.

• Stool Tests: You will be asked to provide one or more stool samples. These will be sent to the laboratory to be tested for bacterial pathogens, parasites, and C. difficile toxin.

Step 2: Blood Tests A doctor will order blood tests to check for:

• Anemia, from chronic blood loss.
• Markers of inflammation, such as C-reactive protein (CRP), which will be elevated.
• Electrolyte abnormalities from diarrhea.

Step 3: Endoscopy and Biopsy

If stool tests are negative and symptoms are persistent, the definitive diagnostic test is a colonoscopy.

• Colonoscopy: A doctor uses a long, thin, flexible tube with a camera to look directly at the entire lining of the colon and rectum. This allows the doctor to see the pattern and severity of the inflammation. For example, in UC, the inflammation is continuous from the rectum, while in Crohn’s disease or ischemic colitis, there may be “skip lesions” with patches of healthy tissue in between.
• Biopsies: During the colonoscopy, the doctor will take multiple tiny tissue samples from the colon lining. These are examined by a pathologist under a microscope. The specific microscopic pattern of inflammation can definitively confirm a diagnosis of ulcerative colitis or Crohn’s disease.

Clinically, I rely on stool studies, flexible sigmoidoscopy, and sometimes CT abdomen to confirm inflammation and rule out life-threatening causes like ischemic colitis.

Treatment of hemorrhagic proctocolitis depends entirely on the underlying cause.

• For Infectious Colitis: The treatment is a course of the specific antibiotic or antiparasitic medication that is effective against the identified pathogen.
• For Ischemic Colitis: Treatment is usually supportive, involving bowel rest, intravenous (IV) fluids, and antibiotics. In severe cases where the colon tissue has died, surgery may be necessary.
• For Radiation Proctocolitis: Treatment is focused on managing symptoms with medications that can help reduce bleeding and inflammation.
• For Inflammatory Bowel Disease (UC or Crohn’s): There is no cure, so treatment is a lifelong process aimed at controlling the inflammation. This typically follows a “step-up” approach:
  • 5-ASA Medications (e.g., mesalamine): These are anti-inflammatory drugs that are the first-line treatment for mild to moderate disease.
  • Corticosteroids: Used for short periods to bring a severe flare under control.
  • Immunomodulators: Medications like azathioprine that suppress the immune system to maintain remission.
  • Biologic Therapies: Advanced, targeted medications that block specific inflammatory proteins.
  • Surgery: In severe, unresponsive cases of UC, removal of the colon (a colectomy) may be necessary.

Clinically, ischemic cases often resolve with conservative care, while infectious or inflammatory forms may require targeted antibiotics or corticosteroids, depending on the underlying cause.

Hemorrhagic proctocolitis is a serious and distressing clinical syndrome characterized by bloody diarrhea and rectal urgency. It is not a single disease, but a clear sign of significant inflammation in the large intestine that demands a medical evaluation. The causes are diverse, ranging from a curable bacterial infection to a chronic, lifelong autoimmune disease like ulcerative colitis. The most important step for any person experiencing these symptoms is to see a doctor for a thorough investigation, beginning with simple stool tests to rule out infection. An accurate diagnosis is the only way to ensure you receive the correct treatment, which is the key to resolving the inflammation, stopping the bleeding, and restoring your digestive health and quality of life. Clinically, I’ve found that managing hemorrhagic proctocolitis involves a balance of supportive care, targeted therapy, and close monitoring, especially in elderly or immunocompromised patients.

American College of Gastroenterology (ACG). (n.d.). Bloody Stools. Retrieved from https://gi.org/topics/bloody-stools/

Crohn’s & Colitis Foundation. (n.d.). What is Ulcerative Colitis? Retrieved from https://www.crohnscolitisfoundation.org/what-is-ulcerative-colitis

Centers for Disease Control and Prevention (CDC). (2023). Infections from some food or animals. Retrieved from https://www.cdc.gov/foodsafety/diseases/index.html