Overview
Ascaris lumbricoides (roundworm) is a parasitic disease that occurs in the small intestine and other organs of the human body. The main symptoms are low-grade fever, cough, asthma, abdominal pain, vomiting, and cessation of bowel movement and defecation, etc. The disease occurs when the parasite comes into contact with soil contaminated with eggs of infective ascarid worms, and then enters the mouth by hand or consumes contaminated vegetables and fruits, and is mainly treated with deworming using benzimidazole.
Definition
Ascariasis is a chronic infectious disease caused by the parasitic worm Ascaris lumbricoides (short for roundworm) in the human small intestine or other organs.
The larvae can migrate in the body and cause visceral migrans or ocular migrans.
Pathogenesis
Ascariasis is the most widespread human helminthiasis in the world and is endemic in temperate, subtropical and tropical regions.
The incidence is high in developing countries. According to the World Health Organization (WHO) Expert Committee on Epidemiology classification, most of the rural areas in China belong to the severe (infection rate of more than 60%) and moderate (infection rate of 20% to 60%) endemic areas.
Causes
Causes
Source of infection
Patients and carriers, are the main sources of infection.
Animals such as pigs, dogs, chickens, cats and rats, as well as insects such as flies, which can carry eggs or excrete live eggs after swallowing, can also be sources of infection.
Transmission
Through fecal-oral transmission.
Farm labor or crawling on the ground contact with contaminated soil, eggs through the hands of the entrance.
Eating fresh vegetables, fruits and melons with live eggs is easy to be infected.
Eggs can also be inhaled along with dust, causing infection.
Susceptible people
People are generally susceptible.
Children are susceptible to Ascaris lumbricoides eggs by crawling on the ground and sucking fingers, especially during the school age.
The infection rate is high in rural areas that are fertilized with human excreta that have not been harmlessly treated.
Predisposing factors
Age
Children prefer crawling on the ground, have unhygienic behaviors such as finger-sucking, etc., which can easily cause infection.
Temperature
22~24℃ is the suitable growing temperature for Ascaris lumbricoides. Ascariasis is more common in warmer climates.
Environment
Rural areas that are used to fertilize with human excreta are more susceptible to Ascariasis.
Pathogenesis
Adult Ascaris lumbricoides parasitize the small intestine of human body, and the eggs laid by female Ascaris lumbricoides can be excreted with feces, and develop and mature under suitable environment, which is infectious.
After the eggs enter the human body, the larvae hatch in the small intestine, penetrate into the intestinal wall and migrate to the liver, enter the alveolar cavity through the right heart, along the bronchial tubes and trachea to the pharynx, and then be swallowed to the small intestine and gradually develop and mature into adult roundworms.
As the larvae pass through the lungs, their metabolites and larval death can induce localized injury and inflammatory responses in the body.
In severe infections, lung lesions may fuse into patches, and inflammation of the bronchial mucosa occurs, leading to bronchospasm and asthma.
Adult worms parasitize the jejunum and upper ileum, causing epithelial cell loss or mild inflammation. Large numbers of adult worms can become entangled and cause intestinal obstruction.
Larvae may also migrate with the bloodstream to other organs and usually do not develop into adult worms, but can cause organ damage.
Adult Ascaris lumbricoides can also migrate to other places and bore holes, which can cause biliary ascariasis, Ascaris lumbricoides intestinal obstruction, such as obstruction of the trachea, bronchus can cause asphyxiation and death, and can also be drilled into the appendix or pancreatic ducts to cause inflammation. Roundworm eggs and roundworm fragments may also be associated with gallstone formation.
Symptoms
Symptoms and severity of human roundworm infection vary greatly, depending on the number of worms and the body’s reactivity. Most patients have no obvious symptoms, but children, the frail or malnourished are prone to symptoms.
Ascaris lumbricoides migrans
Symptoms caused when larvae migrate from the intestines into the body, mainly include:
Low-grade fever: passing through the lungs leads to an inflammatory reaction, damage to capillaries and cellular infiltration, and fever.
Cough: an inflammatory reaction in the lungs and bronchial tubes, causing a cough.
Asthma-like attack: Inflammation of the mucosa as it migrates to the bronchial tubes, causing an asthma-like attack with the clinical manifestation of dyspnea.
Impairment or loss of vision: Ocular larval migrans may occur in older children, usually unilaterally, and may result in uveitis and/or choroidal retinitis, which may be characterized by ocular pain and discomfort and impaired or lost vision.
Intestinal Ascariasis
The clinical manifestations of intestinal ascariasis are related to the number of roundworms and the site of parasitization.
In mild cases, there are no symptoms.
A large number of roundworm infections may cause lack of appetite or increased food intake and easy hunger.
Abdominal pain, pain when pressing around the umbilicus, recurring at irregular intervals.
Some patients are irritable and easily startled, or depressed and grind their teeth.
Severe infections can lead to malnutrition and affect growth and development.
Complications
Ectopic ascariasis
Ascaris lumbricoides has the habit of drilling holes and can leave the intestine to enter other organs with holes, causing ectopic ascariasis, which is commonly seen in the following types:
Biliary Ascariasis
Prevalent in children and young adults, more common in women. High fever, diarrhea, pregnancy and childbirth can trigger biliary roundworm disease.
The onset is sudden, with severe paroxysmal colicky pain in the middle of the right upper abdomen with a drilling-like sensation.
Tossing and turning, nausea, vomiting, may vomit roundworms.
If Ascaris lumbricoides burrow into the liver, it may cause Ascaris lumbricoides liver abscess, with chills, high fever, pain in the liver area and hepatomegaly.
Pancreatic Duct Ascariasis
Mostly complicated by biliary roundworm disease, the symptoms resemble acute pancreatitis, with persistent epigastric pain, accompanied by nausea and vomiting.
Appendicular Ascariasis
Mostly seen in young children, because the caliber of the root of the appendix is wide, easy for roundworms to enter. It is characterized by abdominal cramps and frequent vomiting.
Others
Ascaris lumbricoides can also enter the brain, eyes, ear, nose and throat, trachea, bronchial tubes, thoracic cavity, abdominal cavity, genitourinary tract and so on.
Ascaris secretions acting on the nervous system can cause headache, insomnia, intellectual developmental disorders, and in severe cases, epilepsy and cervical ankylosis and activity limitation.
Intestinal obstruction
A large number of adult worms entangled into a mass can cause intestinal obstruction, manifested by paroxysmal abdominal cramps, vomiting, stopping of gas (farting), defecation, and
Intestinal perforation
Ascaris lumbricoides can cause intestinal perforation when parasitized in the intestines, manifesting as subacute peritonitis. Fever is unremarkable, accompanied by nausea and vomiting, and abdominal distension becomes progressively more pronounced. A limited peritonitis or abscess may also form.
Allergic reactions
The heterologous proteins of the bugs can cause allergic reactions such as urticaria (rash, symptoms of intense itching of the skin), asthma (symptoms of coughing and wheezing, difficulty in breathing), conjunctivitis (red, dry, painful, self-conscious itching of the eyes).
Seek medical attention
Department of Medicine
Gastroenterology
When abdominal pain or pain when pressing around the umbilicus occurs, it is recommended that you consult a doctor promptly.
Department of Infectious Diseases
After confirming the diagnosis, you can go to the Department of Infectious Diseases for further treatment.
Pediatrics
It is recommended to consult a pediatrician promptly if a child develops any of the above symptoms, or if he/she is irritable, easily startled, grinds his/her teeth, or if his/her growth and development are not up to standard.
Preparation for medical consultation
Preparation for consultation: registration, preparation of documents, common problems
Tips for the doctor
It is recommended to wear loose clothing to facilitate the completion of the examination.
Preparation Checklist
Symptom list
Pay particular attention to the time of onset of symptoms, special symptoms, etc.
Does your stomach hurt?
Does it hurt around the belly button?
How is your mental health?
How long has it been present?
List of medical history
Is it a habit to eat raw fruits and vegetables?
Is there a habit of not washing hands before and after meals?
Does he/she like to suck fingers?
Checklist
Test results in the past 6 months, which can be brought to the doctor’s office
Laboratory tests: blood test, eosinophil test
Imaging tests: abdominal ultrasound, chest X-ray, abdominal CT
Medication list
Medication used in the last 3 months, if available, bring the box or package with you to the doctor’s office.
Dewormers: albendazole, ivermectin, mebendazole
Diagnosis
Diagnosis based on
Medical history
History of living or traveling in areas where roundworm disease is endemic.
Habit of sucking fingers, drinking raw water, eating unwashed fruits.
A family member with ascariasis.
Clinical manifestations
Symptoms consistent with ascariasis, such as low-grade fever, vomiting, diarrhea, and cough.
There is pain on pressure around the umbilicus.
Occasional dry rales bilaterally on lung auscultation.
Laboratory tests
Routine blood tests
Blood leukocytes and eosinophils are increased in larval migration, ectopic ascariasis and concurrent infections.
Pathogenetic examination
Eggs may be detected on fecal smears or by floating in saturated saline. Modified Kato method has a higher detection rate of eggs.
Imaging
Ultrasonography
Ultrasonography can diagnose biliary ascariasis. Abdominal ultrasonography may show roundworms located in the dilated common bile duct or several strong echogenic bands 2 to 5 millimeters wide in the common bile duct.
Precautions: Fasting is required before the abdominal ultrasound examination, and it is necessary to temporarily prohibit eating and drinking after dinner the night before the examination, and adjust the position according to the doctor’s instructions.
X-ray examination
X-ray examination can determine whether there are roundworms in the lungs and other cavities.
Inflammation of the lungs: thickening of the hilar shadows, increased lung texture, and punctate and flocculent infiltrate shadows are seen.
Gastric ascariasis: variable round striated shadows in the stomach.
Duodenal ascariasis: curved, circular, spring-shaped or “8”-shaped images are seen.
Differential diagnosis
Gallstones
Similarities: gallstones and biliary ascariasis have similar symptoms and present as abdominal colic.
Differences: Gallstone colic is often accompanied by chills and fever, the age is usually over 30 years old, and stone-shaped images can be seen on ultrasound.
Hookworm disease
Similarities: both cause abdominal pain, cough, cough sputum, sputum with blood, etc., fever, chills and other symptoms. Nausea, vomiting, diarrhea, etc. occur when it invades the intestinal tract.
Differences: Different types of worm eggs can be found through laboratory tests.
Bronchial asthma
Similarities: The asthma-like attacks caused by the migration of roundworms have the same symptoms as bronchial asthma, with persistent recurrent coughing, often at night or in the early hours of the morning, and exacerbated by exercise.
Differences: Bronchial asthma is often exacerbated at night or in the early hours of the morning, most of which may resolve on their own or with treatment. Imaging shows thickening of the hilar shadows, increased lung veins, and punctate and flocculent infiltrates. Ascariasis can be detected in the feces during laboratory tests, and rounded roundworm-shaped shadows can be detected on imaging in addition to thickening of the hilar shadows and increase in the pulmonary striae.
Acute cholecystitis
Similarity: The symptoms of biliary ascariasis are similar to those of acute cholecystitis, such as acute onset of paroxysmal colic, accompanied by nausea, vomiting, anorexia and constipation.
Differences: In acute cholecystitis, an enlarged gallbladder filled with fluid can be seen on ultrasound, whereas in ascariasis, the shape of roundworms can be seen.
Acute appendicitis
Similarities: Ascaris lumbricoides invades the appendix, causing an attack of acute appendicitis, which is similar to the symptoms of acute appendicitis not caused by Ascaris lumbricoides. For example, abdominal pain, often in the upper abdomen and gradually moving to the lower right abdomen, nausea, vomiting, diarrhea, etc., and in severe cases, fever.
Differences: Ascaris lumbricoides can be found on imaging when it invades the appendix.
Treatment
Principles of treatment: In some cases, ascariasis that is asymptomatic and does not produce ectopic ascariasis and complications may resolve spontaneously, but treatment is required if symptoms develop. The most common treatment is deworming, while severe infections may require surgery.
Deworming
Deworming medications are the mainstay of treatment for ascariasis. Commonly used medications are:
Mebendazole, one of the drugs of choice for the treatment of ascariasis, with an egg negative rate of 90% to 100%. Adverse reactions are mild, occasionally see gastrointestinal discomfort, diarrhea, vomiting.
Albendazole: the negative transfer rate of worm eggs reaches 90%, severe infections need more than one course of treatment, roundworm agitation or even biliary ascariasis may occur in the treatment. use with caution in infants and young children under 2 years old.
Ivermectin: cure rate is nearly 100%.
Piperazine citrate: safe and effective anti-ascaris lumbricoides, suitable for children with complications, prohibited when combined with hepatic and renal insufficiency or epilepsy, and preferably not used when there is intestinal obstruction.
Symptomatic treatment
When fever, vomiting and diarrhea are severe, rehydration, water and electrolyte balance, nutrition and systemic supportive therapy are needed.
When diarrhea is severe, montmorillonite can be used to stop diarrhea.
Treatment of ectopic roundworm disease and complications
Biliary ascariasis is treated with antispasmodic and analgesic, anthelmintic and anti-inflammatory therapy.
Ascaris lumbricoides intestinal obstruction can take soybean oil or peanut oil, and then deworming treatment can be carried out after Ascaris lumbricoides mass is loosened. If the deworming treatment has no effect, timely surgical treatment.
Appendicitis, acute suppurative cholangitis, liver abscess, hemorrhagic necrotizing pancreatitis caused by Ascaris lumbricoides need to be operated as soon as possible.
Prognosis
Cure
Some roundworm infections may resolve spontaneously.
Usually, patients can be cured after deworming treatment.
Dangers
Untreated ascariasis may cause gastrointestinal dysfunction, affecting the intake and absorption of nutrients. Children may have developmental delays or even mental retardation.
When roundworm infection is serious, it may cause complications such as biliary ascariasis, intestinal obstruction, appendicitis and intestinal perforation.
Daily
Daily Management
Dietary management
Eat more vegetables and fruits to supplement sufficient vitamins and trace elements.
Foods rich in dietary fiber such as spinach, oleaginous vegetables, cabbage and coarse grains need to be used when constipation occurs.
Diet should be light and easy to digest, avoid spicy and greasy food, and do not eat barbecue.
When vomiting and diarrhea are severe, you need to eat fluids or semi-fluids.
Avoid overeating and avoid smoking and alcohol.
Life management
Adopt good hygienic habits, wash melons and fruits under running water before eating.
Wash your hands before meals and do not drink raw water.
Do not urinate or defecate anywhere.
Prevention
Wash, peel or cook food before eating.
Separate plates for raw and cooked food when cutting vegetables.
Do not drink raw water.
Wash hands with soap and water or disinfectant before handling food.
Teach children not to crawl on the floor and not to touch food with dirty hands.