Infectious colitis overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Qasim Salau, M.B.B.S., FMCPaed [2]
Overview
History Perspective
In 1893, J. M. T. Finney described pseudomembranes in the colon of a 22 year old post operative patient. Shigella was first discovered by Dr. Kiyoshi Shiga following a bacillary dysentery outbreak in Japan in 1896. Several outbreaks have occurred since then.
Classification
There is no established classification system for infectious colitis. However, it may be classified based on class of the causative pathogen, route of infection, and duration of symptom. Based on the causative pathogen, infectious colitis may be classified into bacterial, viral, protozoan and fungal.
Pathophysiology
Infectious colitis occurs following invasion of colonic mucosa or attachment to the colonic mucosa by a micro-organism causing inflammation. Enteric pathogens that cause colitis are usually transmitted through fecal-oral route especially in children. Infectious colitis may also occur following antibiotics use, especially broad spectrum antibiotics. Infectious colitis may also be acquired as a sexually transmitted infection (STI) among individuals who practice unsafe anal sex especially among men who have sex with men (MSM).
Causes
The most common pathogens that cause infectious colitis are enteric bacteria. They cause colitis by either directly invading the gut or by causing mucosal injury through toxins they produce without invasion. Common pathogens that cause infectious colitis include Shigella dysenteriae, Escherichia coli, Chlamydia trachomatis, Cytomegalovirus, HSV. Clostridium difficile can cause colitis in individuals on antibiotic therapy.
Differentiating Infectious colitis from other diseases
Symptoms and signs of infectious colitis are seen in other causes of colitis and some systemic diseases. Infectious colitis must be differentiated from other diseases that cause fever, bloody diarrhea, dehydration, tachycardia and low blood pressure. Therefore, detailed history, physical examination and laboratory tests are needed to make the diagnosis. In addition, endoscopy with biopsy may be required to confirm the diagnosis. In infants and young children, infectious colitis must be differentiated from allergic colitis, necrotizing enterocolitis, intussusception, volvulus and early onset inflammatory bowel disease. In adolescents and adults, infectious colitis must be differentiated from inflammatory bowel disease and colorectal malignancy.
Epidemiology and Demographics
The exact worldwide incidence and prevalence of infectious colitis is not fully known. However, it is estimated that 2 to 4 billion episodes of infectious diarrhea (including infectious colitis) occur annually with the largest burden in developing countries. Enteric bacteria are the most common pathogens causing infectious colitis. The highest morbidity and mortality from infectious colitis is in children under the age of five years.
Risk Factors
Infectious colitis can occur in all age groups. Individuals at high risk of developing infectious colitis or complications of infectious colitis are young children between the age of 1 to 5, the elderly, individuals with immunosuppressive disease such as HIV-positive, men who have sex with men, individuals living in regions with poor sanitation and travelers.
Screening
Screening asymptomatic individuals for the presence of infectious colitis-causing pathogens is not recommended.
Natural History, Complications, and Prognosis
Obtaining a detailed history, including risk factors is important in making a diagnosis of infectious colitis, as it provides an insight into the possible cause infectious colitis. Symptoms of infectious colitis include diarrhea (either watery or bloody), nausea, vomiting, abdominal pain, and bloating with or without fever. The symptoms of infectious colitis are often acute in onset and usually non-recurrent. History of recurrent diarrhea suggests inflammatory bowel disease. History of antibiotic use especially in a hospitalized patients suggests ''Clostridium difficile'' as the possible cause. Less common symptoms may be related to complications of infectious colitis, such as oliguria/anuria, and painless gross hematuria. Abdominal pain and tenderness may be localized, mimicking acute appendicitis.
Diagnosis
History & Symptoms
Obtaining a detailed history, including risk factors is important in making a diagnosis of infectious colitis, as it provides an insight into the possible cause infectious colitis. Symptoms of infectious colitis include diarrhea (either watery or bloody), nausea, vomiting, abdominal pain, and bloating with or without fever. The symptoms of infectious colitis are often acute in onset and usually non-recurrent. History of recurrent diarrhea suggests inflammatory bowel disease. History of antibiotic use especially in a hospitalized patients suggests ''Clostridium difficile'' as the possible cause. Less common symptoms may be related to complications of infectious colitis, such as oliguria/anuria, and painless gross hematuria. Abdominal pain and tenderness may be localized, mimicking acute appendicitis.
Physical Examination
Physical examination of patients with Infectious colitis may be remarkable for abdominal tenderness, fever, and signs of dehydration, such as abnormal orthostatic vital signs, reduced skin turgor, slow capillary refill, and dry mucous membranes. Physical examination among patients with severe dehydration may be remarkable for altered mental status. Physical examination may also show pallor and findings suggestive of complications of the pathogen causing the infectious colitis (e.g. hemolytic uremic syndrome), such as skin pallor, petechiae, and bruises complicating E. coli enteritis.
Laboratory Findings
Diagnostic laboratory tests to identify the pathogens causing infectious colitis may include stool examination (such as microscopy, culture and fecal leukocytes), blood culture, serology, and molecular tests such as polymerase chain reaction (PCR). Non specific laboratory findings in infectious colitis are also done and helpful to rule out development of complications.
Endoscopy
Endoscopy is not routinely indicated in infectious colitis. However, it is useful in cases of diarrhea (bloody or non-bloody) with positive fecal leukocytes, but negative culture. It is also useful in distinguishing inflammatory bowel disease and infectious colitis. In most causes of infectious colitis, endoscopic findings are not pathognomonic. Common endoscopic features in infectious colitis include patchy or diffuse erythematous mucosa, mucosa edema, hemorrhage, with or without ulcers.
X ray
There are no diagnostic x ray findings associated with infectious colitis.
CT
There are no diagnostic CT findings associated with infectious colitis.
MRI
There are no diagnostic MRI findings associated with infectious colitis.
Ultrasound
There are no diagnostic ultrasound findings associated with infectious colitis.
Other imaging findings
There are no other imaging findings associated with infectious colitis.
Other diagnostic studies
There are no other diagnostic studies associated with infectious colitis.
Treatment
Medical therapy
The mainstay of treatment of infectious colitis is the administration of antimicrobials against the causative pathogen. In addition to antimicrobial therapy, general supportive measures is usually given to replace fluid and electrolytes and occasionally blood.
Surgery
The mainstay of therapy in infectious colitis is medical treatment. However, surgery may occasionally be required in the treatment of complications of infectious colitis such as, massive hemorrhage, perforation, abscess, fulminant infectious colitis and failure of medical therapy.
Primary prevention
The transmission of pathogens that cause infectious colitis can be limited by implementing preventive measures which include proper washing of hands especially after contact with animals, including poultry. Ensuring food is properly washed and cooked, avoiding eating raw food that is not washed. Food handlers should maintain high levels of hygiene when preparing, washing and cooking foods. Whenever suffering from fever, diarrhea, and vomiting, food handlers should report to their employers immediately. Producers of fruits and vegetables should also practice good hand hygiene, protect fields from fecal contamination, evaluate quality of water, and hygiene of the storage equipment.
Secondary prevention
There are presently no established method for secondary preventive measures of infectious colitis. However, it is important to maintain proper personal hygiene to avoid infectious colitis.