intestinal infection



Overview

Definition

Intestinal infections are diseases caused by pathogenic microorganisms invading the intestinal tract, resulting in intestinal inflammatory reactions and dysfunctions. Pathogenic microorganisms include viruses, bacteria, and parasites. It occurs mostly in infants, young children and the elderly, but can also spread to all other ages. Symptoms include abdominal pain, diarrhea, nausea, vomiting, and abdominal distension, accompanied by inflammation of the intestinal mucosa and intestinal transport dysfunction [1-2].

Classification

The classification of intestinal infections is mainly based on the type of pathogen and the severity of the disease:

By pathogen type

Viral intestinal infections

Characterized by a relatively short course of the disease, with diarrhea, nausea, and vomiting as the main symptoms. Common viruses are rotavirus, norovirus, and adenovirus [3-4].

Bacterial intestinal infections

Characterized by a prolonged course of illness accompanied by fever, chills, abdominal pain, and may lead to sepsis in severe cases. Common pathogenic bacteria include Salmonella, Shigella, and Escherichia coli.

Parasitic intestinal infection

Characterized by symptoms such as diarrhea, abdominal pain, and lethargy. Common parasites include GI protozoa, roundworms, hookworms, toxoplasmosis, etc.

According to the duration of the disease

Acute intestinal infection

Symptoms appear rapidly, the course of the disease is short, usually within a few days to recover on their own. Some patients with strong pathogens or weak immunity may have a longer course and may become chronic.

Chronic intestinal infections

Longer duration, milder symptoms or intermittent episodes, common in patients with low resistance, prone to nutritional and metabolic disorders and affect the quality of life. It requires long-term medication and life modification.

Causes

The main cause of intestinal infections is infection by various pathogens, including bacteria, viruses, parasites and so on [3-4].

Pathogenic causes

Viruses

Such as rotavirus, norovirus, adenovirus, etc.

Bacteria

Such as Salmonella, Shigella, Escherichia coli, Vibrio cholerae, etc.

Parasites

Such as protozoa, roundworms, hookworms, toxoplasmosis in the digestive tract [5].

Predisposing factors

Dietary impurity

Food contamination or unhygienic food may lead to invasion of pathogens into the intestinal tract.

Contamination of water sources

Exposure to or consumption of contaminated water sources may allow pathogens to enter the intestinal tract.

Environmental uncleanliness

Living in an unsanitary environment, pathogens are spread to others through air or contact.

Predisposing factors

Age: Infants, young children and the elderly are more susceptible to enteric pathogens due to their weakened immune systems.

Immunocompromised: Patients with immune system disorders or immunosuppressed states are susceptible to enteric pathogens.

Chronic diseases: Patients with chronic diseases such as enteritis, hepatitis or diabetes are susceptible to enteric infections.

Pathogenesis

Pathogens enter the host and cause intestinal dysfunction through direct damage to intestinal mucosal cells, production of toxins, or triggering an immune response, leading to mucosal inflammation, impaired intestinal transport, and the development of uncomfortable symptoms [6].

Different pathogens may have different mechanisms of action in the pathogenesis. For example, in viral intestinal infections, viruses invade the intestinal mucosal cells, destroying the intestinal barrier and triggering inflammation; in bacterial intestinal infections, bacteria damage the intestinal mucosal cells through toxins or invasive factors; and in parasitic intestinal infections, the parasite damages the intestinal tract in the process of reproduction and migration in the intestinal tract.

Symptoms

The main manifestations of intestinal infections are diarrhea, abdominal pain, nausea and vomiting [3-4].

The main symptoms

Diarrhea.

Typical symptoms of intestinal infections, which may be characterized by increased frequency of stools, loose or watery stools, which may be accompanied by pus and blood.

Abdominal pain

Abdominal discomfort or pain, which may be acute or persistent, mostly around the navel or over a wide area of the abdomen.

Nausea and vomiting

Irritation by intestinal pathogens, manifested by a feeling of nausea, which may be accompanied by vomiting.

Other symptoms

In addition to the main symptoms, intestinal infections can be accompanied by fever and malaise.

Fever

Some patients with intestinal infections may have a low or high fever.

Fatigue

This may be characterized by general weakness, fatigue and loss of appetite.

Complications

Complications such as dehydration, intestinal obstruction, sepsis, and intestinal flora imbalance may occur with intestinal infections.

Dehydration

Loss of water due to massive diarrhea and vomiting can cause symptoms of dehydration, such as thirst, low urine output, and loss of skin elasticity. When repeated, it can lead to electrolyte imbalance and affect cardiac and renal function [7].

Intestinal obstruction

Some patients with intestinal infections may develop intestinal obstruction and require urgent treatment.

Sepsis.

Severe bacterial intestinal infections may lead to sepsis, in which pathogens enter the circulation and have systemic effects [1].

Imbalance of intestinal flora

Intestinal infections may lead to replacement of normal flora by pathogens, triggering an imbalance in the intestinal flora.

Seek medical attention

When symptoms such as diarrhea and abdominal pain occur, one should go to the gastroenterology department; infants and young children with related symptoms should go to the pediatric internal medicine department; if severe abdominal pain, severe dehydration, and other serious conditions occur, the emergency department should be consulted.

Department of Medicine

Gastroenterology

When symptoms of intestinal infections such as diarrhea, abdominal pain, nausea and vomiting occur, it is recommended to consult the Department of Gastroenterology in a timely manner.

Pediatrics

Infants and young children with symptoms of intestinal infections should go to the Department of Pediatrics.

Emergency Medicine

If the symptoms of intestinal infection are severe, such as severe abdominal pain, repeated vomiting, and severe dehydration, it is necessary to go to the Emergency Department in a timely manner.

Preparation

Consultation: Registration, Preparation of documents, Frequently asked questions

Tips for the Emergency Department

It is recommended to wear loose clothing to the clinic to facilitate the physical examination.

Record the changes and characteristics of your condition for your doctor’s reference.

Patients with symptoms such as severe dehydration are advised to be accompanied by their family members.

Preparation Checklist

Symptom list

Particular attention should be paid to the time of onset of symptoms, special manifestations, etc.

Are there any symptoms such as diarrhea, abdominal pain, nausea, vomiting, etc.? When did they first appear?

How does the frequency and nature of diarrhea change?

Is there any fever, malaise, etc.? To what extent?

Are there any symptoms of dehydration, such as thirst, low urine output, and loss of skin elasticity?

Medical History Checklist

Are there any other members of the family with intestinal infections?

Have there been similar symptoms in the past? What kind of treatment has been received?

Any recent exposure to environments where pathogens may be present, e.g., unsanitary diet, dirty water sources, etc.?

Checklist

Test results from the last 6 months to bring to the doctor’s office

Routine blood, stool, electrolytes, and enteric pathology tests.

Medication list

Medication used in the last 3 months, if available in boxes or packages, bring with you to the doctor’s office

Antibiotics: fluoroquinolones (e.g. norfloxacin, levofloxacin), cephalosporins (e.g. ceftriaxone), etc.

Antiviral drugs: e.g. ribavirin, etc.

Diagnosis

The diagnosis of intestinal infection is mainly based on clinical manifestations and relevant examination results. Combined with the detection of pathogens, clinical symptoms, epidemiological history of comprehensive consideration to determine the diagnosis.

Diagnosis is based on

Medical history

The following is not necessary for the diagnosis of the disease, but if there is a history of the following diseases, it can provide some reference significance for the diagnosis of the disease.

Family history of intestinal infections.

Past symptoms of similar intestinal infections.

Recent exposure to environments where pathogens may be present, such as unsanitary diets, dirty water sources, etc.

Clinical manifestations

There are typical symptoms such as diarrhea, abdominal pain, nausea and vomiting.

Laboratory Tests

Routine blood tests

To find out if there is a systemic reaction to the infection, such as elevated white blood cell count and elevated neutrophil ratio.

Stool routine

Examination may reveal abnormal manifestations such as occult blood, pus and blood, mucus, etc.

Electrolytes

The main assessment is whether it leads to electrolyte disorders, such as whether the concentration of sodium, potassium and chloride ions is abnormal.

Intestinal Pathogenesis

Pathogen testing of stools, such as bacterial culture and viral testing, to identify the pathogen.

Differential diagnosis

Acute gastroenteritis

Similarities: both manifest as abdominal pain, diarrhea, nausea, vomiting and other symptoms.

Differences: Acute gastroenteritis is mainly a viral infection, with a shorter course, often resolving on its own within 3-5 days.

Intussusception

Similarities: Both may present with symptoms such as abdominal pain, diarrhea, and vomiting.

Differences: The causes of intussusception are mostly localized enteritis, intestinal tumors, etc., which are manifested by acute abdominal pain, vomiting and blood in stool.

Inflammatory bowel disease

Similarity: both may present with abdominal pain, diarrhea and other symptoms.

Differences: Inflammatory bowel disease symptoms are persistent or recurrent, such as chronic abdominal pain, chronic diarrhea, blood in stool, etc. [8].

Treatment

Aim of treatment: relieve symptoms, eliminate pathogenic bacteria, prevent complications and recurrence.

Treatment principles: pathogen-specific, symptomatic supportive therapy, individualized treatment.

Drug treatment

Antibiotics

For bacterial intestinal infections, such as Escherichia, Salmonella, etc., antibiotic treatment is used [9-10].

Commonly used drugs such as fluoroquinolones (e.g., norfloxacin, levofloxacin), cephalosporins (e.g., ceftriaxone).

The use of antibiotics should follow the principles of indications, correct dosage and reasonable course of treatment, and try to avoid blind use before a clear diagnosis.

Antiviral drugs

For viral intestinal infections, such as rotavirus, norovirus and so on.

Antiviral drugs such as ribavirin can be used.

The key to treating viral intestinal infections is timely rehydration and correction of electrolyte disorders.

Symptomatic support

Rehydration and electrolyte balance

For dehydration and electrolyte disorders caused by diarrhea, timely replenishment of water and electrolytes, oral rehydration salts or intravenous rehydration.

Dietary adjustments

At the initial stage of intestinal infection, food can be temporarily stopped to reduce the burden on the intestinal tract. Gradually resume the diet after the symptoms of abdominal pain and diarrhea are relieved, such as adopting a low residue and easy-to-digest diet.

Nutritional support

When the disease is severe, nutritional support is needed, such as using intravenous nutritional solution such as amino acid and fat milk. Supplement vitamins and trace elements appropriately.

Prognosis

The prognosis of intestinal infections is mostly favorable, but is affected by pathogens, patient differences and treatment regimens. It may also lead to hazards such as dehydration, electrolyte disorders, malnutrition, and affect the balance of intestinal flora.

Cure

The prognosis for intestinal infections is usually good, and most patients recover fully with prompt and correct treatment. The exact cure depends on the type of pathogen, individual differences and treatment measures.

Generally speaking, viral intestinal infections have a shorter and more self-limiting course; bacterial intestinal infections can effectively eliminate the pathogen and recover after treatment with antibiotics.

Prognostic factors

The prognosis of intestinal infections is influenced by a variety of factors, and the following factors may affect the prognosis.

Type of pathogen

The prognosis of intestinal infections caused by different pathogens may be different. For example, viral intestinal infections usually have a shorter duration of illness and have a favorable prognosis, whereas bacterial intestinal infections may lead to complications if left untreated.

Individual differences

Factors such as age, physical fitness and immunity may affect the prognosis of intestinal infections, e.g. infants, young children, the elderly and patients with suppressed immune systems have a relatively poorer prognosis.

Timeliness of treatment

Timely and correct treatment can improve prognosis and prevent complications.

Comorbidities

The prognosis is relatively poor for patients with comorbidities, such as diabetes mellitus and kidney disease.

Harmfulness

There are certain hazards of intestinal infections, which are mainly manifested in the following aspects:

Dehydration

Due to the persistence of symptoms such as diarrhea and vomiting, patients with intestinal infections are prone to dehydration, which may also lead to shock in severe cases.

Electrolyte disorders

Symptoms such as diarrhea and vomiting caused by intestinal infections may lead to electrolyte imbalances such as sodium, potassium and chloride, which may affect neuromuscular function and even lead to serious complications such as cardiac arrhythmia.

Malnutrition

Intestinal infections affect the patient’s appetite and intestinal absorption of nutrients, which may lead to malnutrition.

Complications

Intestinal infections may lead to intestinal or systemic complications, such as intestinal bleeding, intestinal perforation and sepsis, affecting the patient’s life and health.

Imbalance of intestinal flora

Intestinal infections or anti-infective treatments may alter the balance of intestinal flora, aggravating the condition or affecting health.

Daily

Daily management of intestinal infections includes maintaining a light, easily digestible diet, maintaining personal hygiene, exercising appropriately, keeping a good state of mind and closely monitoring changes in condition.

Daily Management

Dietary management

Daily diet should be kept light and be easily digestible and low in residue. Eat more vegetables, fruits and protein-rich foods. Try to eat less and more meals to reduce the burden on the intestinal tract [11].

Avoid eating too much spicy, greasy and high-fiber foods.

Life management

Maintain good personal hygiene habits, such as washing hands frequently, changing clothes, and cleaning the living environment regularly. Avoid sources of exposure such as unclean food and contaminated water.

Appropriate light physical exercise to enhance body immunity.

Psychological support

Maintain a good state of mind, avoid depression, anxiety and tension, face the disease positively and believe that you can recover.

Disease monitoring

Pay attention to changes in GI symptoms such as diarrhea, abdominal pain, nausea and vomiting on a daily basis.

Closely observe changes in urine output and body temperature.

Follow-up review

Adjust the dosage of medication according to the results of the follow-up examination. Regular follow-up can keep abreast of the changes in the condition and provide early symptomatic treatment, which can delay the progression of the disease as well as prevent the occurrence of complications.

Arrange the time and items for review according to your condition and the doctor’s recommendation. Under normal circumstances, a review can be done every 2 weeks.

Blood tests, stool tests, electrolytes, pathology and other related tests may be needed.

Prevention

Prevention of intestinal infections focuses on causative and predisposing factors, and can help reduce the risk of morbidity through the following healthy lifestyles and measures [11]. The following are prevention methods and measures for different populations:

General population

Dietary management: keep diet clean and hygienic, food well cooked, choose uncontaminated food and water sources, and avoid eating pathogens contaminated from raw water or food.

Personal hygiene: Develop good personal hygiene habits and wash hands frequently, especially after food preparation, eating and toileting.

Living environment: Keep the home and working environment clean and tidy, and carry out regular garbage removal and disinfection to avoid the breeding of pathogens.

Infants, young children and the elderly

For infants, young children and the elderly, whose immune systems are relatively weak, in addition to following the preventive measures for the general population, it is also necessary to monitor their appetite, mental status and excretion to detect pathogen infections in time.

Reasonable intestinal flora regulation, such as regular probiotic supplementation, is recommended for high-risk groups to help restore and maintain normal intestinal flora balance.

Travelers

During travel, pay special attention to the safety of drinking water, avoid drinking raw water that has not been purified and treated, use bottled or boiled water, and make sure to wash your hands frequently.

Try to avoid eating in places with poor sanitary conditions.