Pulmonary pleural amoebiasis

　　First, Etiology

　　There are more than 10 species of Amoeba protozoa parasitizing in humans, only the pathogenic tissue-destroying Amoeba protozoa are pathogenic to humans. Trophozoites are the parasitic form of the protozoa, existing in the body in the form of large trophozoites and cysts. The large trophozoites are the pathogenic type, and the small trophozoites are the intermediate transitional type between trophozoites and cysts. Mature cysts are infectious and have strong resistance to the external environment, surviving for more than 2 weeks in feces and more than 5 weeks in water, and are the only morphological form for the transmission of the disease. The pathogenicity of pathogenic Amoeba is characterized by the unique coding gene for protease hydrolysis, which has an important impact on the ability to invade tissues.

　　Second, Pathogenesis

　　In the infection of Amoeba protozoa, 90% are asymptomatic infections, and 10% develop invasive amoebiasis. This mainly depends on the characteristics of the infecting strain, as well as the host's immune status, nutritional status, and resistance. After a person ingests food or water contaminated with cysts, due to the anti-gastric acid action of the cysts, they smoothly reach the lower segment of the small intestine. With the catalytic action of trypsin, the intracellular amoebae emerge from the cysts, divide into small trophozoites, and settle in the intestinal lumen. Under normal colon function, the small trophozoites stop their activity, secrete cyst walls to form cysts, and are excreted with feces. When the host's resistance decreases or the intestinal function is紊乱, the small trophozoites invade the intestinal wall, multiply in large numbers, and transform into large trophozoites. The pathogenic protozoa directly contact and adhere to target cells, phagocytize and dissolve tissue cells. The trophozoites release hydrolytic proteases that cause tissue dissolution and necrosis, and at the same time, have resistance to complement, adhere to neutrophils involved in the host's response, release more enzymes, exacerbate tissue inflammation and destruction, and form abscesses.

　　90% of pulmonary, pleural, and abdominal amebiasis are of hepatic origin. They can be caused by the rupture of liver abscess into the pleura and lung; through the tissue spaces, blood vessels at the liver, diaphragm, and lung adhesions; through the inferior vena cava from the hepatic vein to the lung and pleura. The intestinal source is that the trophozoites enter the lung through the superior vena cava or inferior vena cava from the intestinal wall lesions through the intestinal lymphatic vessels and thoracic duct.

　　Amebic pleuropulmonary disease can complicate with amebic meningoencephalitis, amebic dysentery, amebic liver abscess, and other common respiratory medicine diseases.

　　1. Amebic meningoencephalitis is a central nervous system infection caused by Naegleria fowleri, a pathogenic strain of the thermophilic genus Naegleria. The clinical onset is acute, rapid, and the prognosis is extremely poor.

　　2. Amoebiasis, also known as intestinal amebiasis, is an intestinal infectious disease mainly characterized by dysentery symptoms caused by pathogenic tissue amoeba. The trophozoites侵入the colonic wall.

　　3. Amebic liver disease is caused by the invasive tissue amoeba trophozoites entering the liver through the portal vein, causing liver cell dissolution and necrosis, forming abscesses, commonly known as amebic liver abscess. The main clinical manifestations are prolonged fever, systemic consumption, liver enlargement and tenderness, and increased leukocytes, and it is prone to cause chest complications.

　　1. The onset is acute, often accompanied by chills, fever (usually remittent fever), accompanied by general symptoms such as fatigue and lack of appetite, cough, expectoration, initially dry cough or mucopurulent sputum, and the typical sputum is chocolate-like. When the liver abscess breaks through into the lung, a large amount of brownish sputum may be coughed up suddenly, with the amount of sputum reaching more than 500ml per day, and there may be sputum with blood or even massive hemoptysis. When the liver abscess breaks through into the pleural cavity, it is often accompanied by severe chest pain and difficulty breathing, and in severe cases, pleural shock may occur.

　　1. Early patients may have no obvious signs, but later, common symptoms include dullness on percussion in the lower right lung, decreased breath sounds, dry and wet rales, and signs of pleural effusion. In patients with liver abscess, the liver is enlarged and tender. There may be pain and difficulty breathing, and in severe cases, pleural shock may occur when the liver abscess breaks through into the pleural cavity.

　　1. Prognosis:Generally considered to have early diagnosis and treatment with excellent prognosis. However, in the late stage or with multiple perforation complications, the prognosis is poor.

　　2. Prevention:Promote health education, pay attention to personal hygiene, strengthen fecal management to prevent water source pollution, thoroughly treat patients and carriers, eliminate the source of infection. Treat patients and carriers of cysts, boiling drinking water, not eating raw vegetables to prevent food contamination. Prevent the breeding of flies and exterminate them. Examine and treat carriers of cysts and chronic patients engaged in the catering industry, and pay attention to personal hygiene such as washing hands before meals and after defecation.

　　1. Hematological examination

　　Increased blood leukocytes, eosinophils, anemia, hypoalbuminemia, and accelerated erythrocyte sedimentation rate are common in chronic patients.

　　2. Pathogen examination

　　Amoebae can be found in sputum and pleural effusion, but the positive rate is only 15% to 20%.

　　3. Serological examination

　　Amoebic antibodies can be measured by indirect fluorescent antibody test, indirect hemagglutination test, enzyme-linked immunosorbent assay, etc., with a positive rate of more than 95% and high specificity. However, due to the long duration of antibodies, the activity of the lesion should be determined in combination with clinical findings. The detection of amoebic antigens in pus and biopsy tissues by immunoelectrophoresis is faster than detecting antibodies and is helpful for diagnosis and prognosis.

　　4. X-ray透视检查

　　The lesions are often located in the lower lobe of the right lung, with the most common basal segment in the past, the right diaphragm elevated, pleural reaction or pleural effusion, a large area of high-density infiltrative shadow in the lower lobe of the right lung, visible liquid level and irregular abscess wall, and blood源性manifests as multiple small abscesses in both lungs.

　　I. Foods that are good for the body for pleurisy caused by amebiasis

　　Pay attention to dietary diversity, eat more vegetables and fruits, more seafood, and more fungal foods.

　　II. Foods not to eat for pleurisy caused by amebiasis

　　In terms of diet, it is necessary to quit smoking and drinking, not to eat spicy and stimulating foods, and to eat less greasy, fried, and fatty foods.

　　(The above information is for reference only, please consult a doctor for details.)

　　I. Treatment

　　1. Antiamoebic treatment

　　(1) Metronidazole (Flagyl): The first-line drug for the treatment of amebiasis at present, effective for all parts inside and outside the intestines. Adults 400-600mg, three times a day, oral or intravenous infusion, 7-10 days as one course. It can be repeated if necessary. Side effects include nausea, vomiting, fatigue, dizziness, etc., and pregnant women should be cautious. Metronidazole sulfone has a similar effect to metronidazole, taken 2g at a time, 3 days as one course, and another course can be taken every 3-7 days according to the condition.

　　(2) Dihydroemetine (dihydro-emetine): Has a direct killing effect on the tissue-invasive ameba, with the highest concentration in liver tissue, suitable for extra-intestinal amebiasis. Adults 1mg/kg, intramuscular injection, 5-10 days as one course. This drug has a high toxicity, the therapeutic dose is close to the toxic dose, and its application is restricted due to its toxicity to the heart and nervous system.

　　2. Puncture and drainage:In the treatment of amebic pleurisy, active puncture and drainage of pus or insertion of a catheter for drainage should be performed at the same time as drug treatment.

　　3. Antibiotics:When there is mixed infection, antibiotics should be used for systemic treatment according to the characteristics of pus and the results of bacterial culture.

　　4. Surgical treatment:Long-term内科treatment without remission, chronic lung abscess, long-term existence of bronchopleural fistula, poor drainage of large amount of pleural puncture, and resection of lung lobe or incisional drainage may be considered.

　　II. Prognosis

　　Generally considered to have early diagnosis and treatment with excellent prognosis. However, in the late stage or with multiple perforation complications, the prognosis is poor.