Enterocolitis: Symptoms, Types, Causes and Treatment

Enterocolitis is a term that covers a group of conditions characterized by inflammation of the small intestine (enteritis) and the colon (colitis). It can affect people of all ages and has many causes, from infections to immune system dysfunctions and complications from medical treatments. Understanding the symptoms, types, underlying causes, and available treatments is crucial for patients, caregivers, and healthcare professionals alike. This article provides a comprehensive overview of enterocolitis, synthesizing the latest research and clinical insights.

Symptoms of Enterocolitis

Recognizing the symptoms of enterocolitis is essential for early diagnosis and management. Symptoms can range from mild to life-threatening, depending on the underlying cause and severity. While some symptoms are common to all types, others may be specific to certain forms of the disease.

Symptom	Description	Severity Range	Sources
Diarrhea	Frequent, loose, or watery stools	Mild to severe	1 2 10
Abdominal pain	Cramping, distension, or generalized pain	Mild to severe	1 2 10
GI bleeding	Blood in stool (hematochezia or melena)	Mild to life-threatening	1 2 4
Fever	Elevated body temperature	Mild to high	2 5
Vomiting	Nausea and expulsion of stomach contents	Occasional	2 11
Lethargy	Fatigue, weakness, or decreased activity	Variable	6 11
Distension	Swelling or bloating of the abdomen	Moderate to severe	1 2 5

Table 1: Key Symptoms of Enterocolitis

Common Presentations

Most patients with enterocolitis present with diarrhea and abdominal pain. Depending on the severity, the diarrhea may contain blood or mucus. Abdominal pain can range from mild cramping to severe, persistent pain, sometimes associated with abdominal distension and tenderness 1 2.

Severe and Complicated Symptoms

In severe cases, enterocolitis can lead to high fever, significant gastrointestinal bleeding, and even signs of shock. Some patients—especially infants and immunocompromised individuals—may develop lethargy, vomiting, or toxic appearance, indicating a potentially life-threatening situation 2 6 11.

Disease-Specific Symptom Patterns

• Immune-mediated enterocolitis (e.g., checkpoint inhibitor-induced): Often features cramping, diarrhea (sometimes severe), abdominal pain, and bleeding 1 10.
• Neutropenic enterocolitis: Particularly in chemotherapy patients, presents with fever, pain, distension, diarrhea, and GI bleeding; complications can include bacteremia and perforation 2.
• Necrotizing enterocolitis (NEC): In neonates, symptoms include abdominal distension, feeding intolerance, bloody stools, and lethargy 5 6 11.

Types of Enterocolitis

Enterocolitis is not a single disease but a group of related disorders. Understanding the different types helps tailor treatment and anticipate potential complications.

Type	Key Features	Affected Population	Sources
Infectious	Caused by bacteria, viruses, fungi, or parasites	All ages	4 5 6 8 13
Necrotizing (NEC)	Intestinal necrosis, high mortality	Premature infants	3 5 6 8 9 11
Neutropenic	Occurs with low neutrophils, post-chemotherapy	Cancer patients	2
Immune-mediated	Triggered by immune checkpoint inhibitors	Cancer patients	1 10
Hirschsprung-associated	Related to colonic nerve absence (aganglionosis)	Children with HSCR	7
NSAID-induced	Linked to NSAID use, can cause severe lesions	Adults, horses	4

Table 2: Major Types of Enterocolitis

Infectious Enterocolitis

This is the most common form and can be caused by various pathogens, including bacteria (Clostridium difficile, Salmonella, etc.), viruses, fungi, and parasites. It can affect anyone, from healthy adults to vulnerable populations 4 5 6 8 13.

Necrotizing Enterocolitis (NEC)

NEC is a severe, often life-threatening disease mostly seen in premature infants. It involves intestinal tissue death and inflammation, with a complex and multifactorial pathogenesis 3 5 6 8 9 11. NEC can present with different forms and is considered a syndrome rather than a single disease.

Neutropenic Enterocolitis

Also known as typhlitis, this type occurs in patients with very low neutrophil counts, often following aggressive chemotherapy. It is characterized by rapid progression and high risk of complications such as bowel perforation and bacteremia 2.

Immune-Mediated Enterocolitis

This occurs as a side effect of immune checkpoint inhibitors used in cancer therapy. The overactive immune response targets the gut, causing colitis and, sometimes, enteritis 1 10.

Hirschsprung-Associated Enterocolitis

Seen in children with Hirschsprung disease, this form is related to the absence of nerve cells in parts of the colon, predisposing to severe infections and inflammation 7.

NSAID-Induced Enterocolitis

Nonsteroidal anti-inflammatory drugs (NSAIDs) can damage the gut lining, leading to inflammation and, in severe cases, necrosis 4. While the data here is from animal studies, similar mechanisms are suspected in humans.

Causes of Enterocolitis

Enterocolitis has a wide range of causes, often depending on the type and patient population. These causes can be infectious, immune-mediated, drug-induced, or related to underlying health conditions.

Cause Type	Mechanism/Trigger	Typical Scenario	Sources
Infectious	Bacterial, viral, or fungal invasion	Outbreaks, immunosuppressed	4 5 6 8 13
Ischemic	Reduced blood flow to the intestines	NEC, severe illness	3 6
Immune-mediated	Immune system attacks gut lining	Cancer immunotherapy	1 10
Chemotherapy	Mucosal injury plus neutropenia	Cancer treatment	2
Formula feeding	Microbiota and immune changes in neonates	Premature infants (NEC)	6 9 11 13
Drug-induced	NSAIDs, antibiotics, others disrupt gut flora	Adults, infants	4 13
Congenital	Nerve absence/motility issues (HSCR)	Children with HSCR	7

Table 3: Causes of Enterocolitis

Infectious Causes

Bacterial, viral, and fungal infections are common causes, especially in infants and immunocompromised patients. Notably, Clostridium difficile and Salmonella are important bacterial triggers. In NEC, bacteria are thought to play a key role, though no single pathogen is consistently identified 4 5 6 8 13.

Ischemic Causes

Reduced blood flow (ischemia) to the intestines, combined with bacterial invasion, is central to the pathogenesis of NEC in infants. This can result from factors like hypoxia and low blood pressure 3 6.

Immune-Mediated and Drug-Induced Causes

Immune checkpoint inhibitors used in cancer therapy can overstimulate the body's immune system, leading to colitis and enterocolitis 1 10. Chemotherapy can cause intense mucosal injury and neutropenia, facilitating infection and inflammation 2. NSAIDs and antibiotics can also disrupt the integrity of the gut lining and the balance of gut microbiota, leading to enterocolitis 4 13.

Dietary and Congenital Factors

Feeding premature infants with formula instead of human milk increases the risk of NEC, likely due to differences in immune and microbiota modulation 6 9 11 13. In Hirschsprung disease, lack of nerve cells in the colon impairs motility and increases the risk of bacterial overgrowth and inflammation 7.

Treatment of Enterocolitis

The treatment of enterocolitis depends on the underlying cause, severity, and patient population. Management can range from supportive care to targeted medical and surgical interventions.

Treatment	Purpose/Mechanism	Population	Sources
Supportive care	Hydration, bowel rest, symptom relief	All	1 2 9 10 11
Antibiotics	Target bacterial infection	Infectious/neutropenic	2 5 6 9 13
Corticosteroids	Suppress immune-mediated inflammation	Immune-mediated	1 10
Biologics	Block specific immune pathways	Refractory immune colitis	1 10
Probiotics	Restore healthy gut microbiota	NEC prevention	9 11 13
Human milk	Immune and microbiota benefits in neonates	NEC prevention	9 11
Fecal transplant	Restore gut flora, reduce inflammation	Experimental/NEC	12
Surgery	Remove necrotic bowel or relieve perforation	NEC, severe colitis	2 9 11

Table 4: Main Treatments for Enterocolitis

Supportive Management

Initial management focuses on stabilizing the patient—ensuring adequate hydration, electrolyte balance, nutritional support, and bowel rest. Symptom control (e.g., pain, diarrhea) is essential, often with anti-diarrheal agents for mild cases 1 2 10 11.

Medical Therapies

Antibiotics

Broad-spectrum antibiotics are crucial in infectious and neutropenic enterocolitis to cover likely pathogens and prevent complications like bacteremia. Antifungal agents may be needed in high-risk patients 2 5 6 9 13.

Immunomodulators

For immune-mediated forms (e.g., checkpoint inhibitor-induced), corticosteroids are the first-line therapy. Biologics such as infliximab and vedolizumab can be used for patients not responding to steroids 1 10.

Microbiota-Targeted Interventions

Probiotics and Human Milk

Probiotics and human breast milk have a protective effect in preterm infants, reducing the risk and severity of NEC by promoting a healthy gut microbiome 9 11 13.

Fecal Microbiota Transplantation

Experimental studies suggest that fecal microbiota transplantation (FMT) may decrease inflammation and damage in NEC, though its use in humans is still investigational 12.

Surgical Intervention

Surgery is reserved for patients with life-threatening complications such as intestinal perforation, necrosis, or severe hemorrhage. In NEC, the decision between peritoneal drainage and laparotomy is still debated 2 9 11.

Emerging and Supportive Therapies

New therapies under investigation include stem cell treatments and controlled hypothermia for NEC. More evidence is needed before these become standard care 11.

Conclusion

Enterocolitis encompasses a wide spectrum of diseases—each with distinct symptoms, causes, and treatments. Early recognition and targeted management are essential for improving outcomes, especially in vulnerable populations like premature infants and cancer patients.

Key Takeaways:

• Symptoms include diarrhea, abdominal pain, GI bleeding, fever, and, in severe cases, lethargy and shock.
• Types range from infectious and necrotizing forms to immune-mediated, neutropenic, and drug-induced variants.
• Causes are multifactorial, involving infections, ischemia, immune dysfunction, medications, and congenital conditions.
• Treatment is tailored to the cause and severity, including supportive care, antibiotics, immunosuppressants, microbiota-targeted therapies, and surgery as needed.

Understanding the nuances of enterocolitis can help guide effective prevention, diagnosis, and treatment, ultimately improving patient care and outcomes.