Overview
It is mainly a respiratory tract lesion caused by migration of roundworm larvae, ectopic parasitism of adult worms and deposition of worm eggs in the lungs, accounting for the second place of ectopic ascariasis (the first place is biliary ascariasis). There are mainly chills, fever, chest tightness, itchy throat, dry cough, urticaria, and a small number of patients may have asthma, dyspnea, blood in sputum, chest pain, headache, convulsions, coma and other symptoms of toxic encephalopathy.
Etiology
People are generally susceptible to roundworms. Ascaris lumbricoides eggs enter the body through the mouth, so people who have the habit of eating raw vegetables and fruits are easily infected. After swallowing the eggs of infected roundworms, they hatch in the small intestine, and the larvae of roundworms break out of their shells and reach the lungs through three ways: ① through the mucosa of the small intestine, microvessels, portal vein, hepatic vein, inferior vena cava, the right heart, and the pulmonary artery to the lungs; ② through the mucosa of the small intestine, lymphatic lymphatic vessels, thoracic duct, and the left heart to the lungs; ③ roundworms pass through the wall of the small intestine and enter into the abdominal cavity and then enter into the lungs through the liver, diaphragm, and the thoracic cavity. Ascaris larvae migrate in the lungs can damage the pulmonary capillaries and alveoli causing pitting hemorrhagic alveoli, bronchiolitis and eosinophilic infiltration mucus secretion increase or eosinophilic granuloma formation once a large number of infections can be hemorrhagic pneumonia and pulmonary lobular embolism. Adult worms may occasionally enter the thoracic cavity to the lungs via the liver, or penetrate into the venous system to the lungs via the right heart, or to the lungs via the pharynx, trachea, bronchus, causing lung abscess, pulmonary embolism or asphyxiation. Female worms may lay eggs locally in the lungs after invasion, causing eosinophilic abscesses, granulomas, and pseudo-tuberculous nodules.
Symptoms
The main symptoms include chills, fever, chest tightness, itchy throat, dry cough, urticaria, and in a small number of patients, symptoms of toxic encephalopathy such as asthma, dyspnea, blood in sputum, chest pain and headache, convulsions, and coma. Signs are often absent or there are scattered dry and wet rales in both lungs, and those with toxic encephalopathy may have pupillary changes and positive Bartholomew’s sign and Kirschner’s sign.
Examination
1. Laboratory examination
In the early stage of acute mass infection with Ascaris lumbricoides, peripheral blood eosinophils can be increased, generally up to 20%～70%, and Ascaris lumbricoides or eggs can be found in sputum.
2. Other auxiliary examinations
X-ray chest radiograph shows scattered, punctate, flocculent or small flaky bordered fuzzy shadows in the lungs.
Diagnosis
According to the comprehensive analysis of epidemiology, clinical manifestations and laboratory examination, Ascaris lumbricoides infection is still mainly diagnosed by parasitology.
Differential diagnosis
Lung damage in pulmonary ascariasis should be differentiated from bronchopneumonia, tuberculosis, and leptospirosis.
Complications
Combined with lung abscess, pulmonary embolism.
Treatment
In addition to the symptomatic treatment of fever, cough, hemoptysis, asthma and other obvious symptoms, the main treatment is drug roundworm.
1. Piperazine (Ascaris lumbricoides)
Piperazine is a commonly used drug to expel roundworms, which can block the neuromuscular connection of the worms and make the worms lose their adsorption ability through anesthesia. The general excretion rate is above 90%.
2.Thiopyrimidine
Broad-spectrum anthelmintic. It can block the neuromuscular connection of roundworms by inhibiting cholinesterase, and paralyze the worms so that they can be discharged with intestinal peristalsis. Pregnant women, young children and people with poor liver function should not take.
3. Albendazole
Albendazole is a commonly used anthelmintic, the efficacy of which is related to the dosage but not to the dosage form. It is contraindicated for pregnant women, lactating women, children under 1 year old and those with poor liver function.
In addition, there are also levamisole and neem tablets, which are less frequently used nowadays.
Prognosis
Pulmonary ascariasis can be cured by early diagnosis and treatment.
Prevention
1. Dispose of feces harmlessly, try not to work in susceptible areas, and advocate wearing shoes on the ground.
2. Pay attention to hygiene, do not eat raw or uncooked food.
3. Groups with a high number of infected persons in endemic areas should be treated comprehensively.