Leptospirosis pneumonia

　　Leptospirosis pneumonia is caused by infection with Leptospira. Leptospira is a slender, filamentous, cylindrical organism with 12 to 18 spirals, with hooks at both ends, measuring 6 to 20 μm in length, and exhibiting active rotary movement. It has strong penetrating power, is Gram-negative, and is easily seen as bright, active spirals under dark-field microscopy. Electron microscopy shows that its structure mainly consists of the outer membrane, flagella (axial filaments), and cylindrical protoplasts (bacteria). Leptospira is aerobic and has low nutritional requirements, grows well in commonly used Korthof's culture medium, and is highly sensitive to drying and general disinfectants, which can be quickly killed. By 1986, 23 serogroups and 200 serotypes had been discovered worldwide. China is known to have 19 serogroups and 74 serotypes. Different serotypes of Leptospira have different virulence and pathogenicity to humans, and some Leptospira have hemolysins or other toxins.

　　Various pathogenic leptospires enter the body through broken skin (or normal skin) or the nasal, ocular, oral, and gastrointestinal mucosa. The pathogen has a strong penetrating power, can quickly penetrate the vascular wall or lymphatic vessels into the blood circulation, reproduce in large numbers in the blood, and invade various organs and tissues. Bacteremia is produced during the incubation period, and toxicosis appears about a week later, causing damage to organs such as the capillaries, lungs, liver, kidneys, heart, and central nervous system.

　　The complications of leptospirosis pneumonia are diverse, with the most prominent manifestations being those in the eyes (uveitis, iritis and ciliary body inflammation) and the brain (aseptic meningitis, occlusive cerebral arteritis), which occur in the late stage (immune response stage).

　　Complications of ocular diseases are mainly glomerulitis, among which the majority are anterior uveitis (iritis and ciliary body inflammation), often accompanied by vitreous opacity and white deposits on the iris surface. Secondly, there are changes in the retina and optic nerve, and some patients also have changes in the sclera, pupil, and ocular muscles. Most of them appear within 2 to 8 weeks of the onset of the disease. The vast majority have a good prognosis, but there are also a few cases with prolonged duration or recurrence.

　　Complications of the nervous system are manifested as late encephalopathy. After the acute phase, symptoms such as persistent headache, dizziness, or limb numbness may appear. Central nervous system symptoms such as central paralysis and motor language disorders may appear 2-5 months after the disease, and some patients may also have psychiatric symptoms. Currently, it is believed that the complications of late encephalopathy may be due to allergic reactions causing vascular stenosis or occlusive lesions in the cerebral blood vessels, leading to impaired blood supply to the brain tissue.

　　The incubation period is 2-28 days, usually 7-12 days. Due to the different immune levels of the infected individuals and the different infected strains, the clinical manifestations are complex and diverse.

　　1. Early (infection toxicemia phase)

　　Within 3 days after onset, the main manifestations are sudden chills, fever, with body temperature up to 39°C, mostly in a remittent fever pattern. It may be accompanied by headache, weakness, conjunctival congestion or hemorrhage, pain and tenderness in the gastrocnemius muscle may appear on the first day, lymphadenopathy may appear on the second day, and it is more common in the inguinal and axillary regions.

　　2. Organ Injury Phase

　　3-10 days after the disease, clinical types are divided according to symptoms.

　　(1) Influenza Typhoid Type: It is the continuation of early symptoms and has no obvious or severe organ damage or dysfunction.

　　(2) Jaundice and Hemorrhagic Type: This is Weil's disease, which is less common in China.

　　(3) Meningoencephalitis Type: Brain membrane irritation symptoms appear within a few days of onset, and in severe cases, there may be convulsions, coma, brain herniation, respiratory failure, and various neurological damage symptoms.

　　(4) Pulmonary Hemorrhagic Type: On the basis of early infection and intoxication syndrome, there is hemoptysis but no obvious lung rales and respiratory dysfunction, known as the common type of pulmonary hemorrhagic type. If there is a reaction of infection and intoxication sepsis at the same time, there is progressive difficulty in breathing, hypoxia, and asphyxia, rapidly developing rales, and X-ray manifestations of diffuse hemorrhagic shadows in both lungs, known as the diffuse pulmonary hemorrhagic type. This type develops rapidly and the disease progresses in three stages.

　　①Prodromal Period: The patient's complexion becomes pale, restlessness gradually increases, breathing and heart rate progressively increase, and there are scattered, gradually increasing dry and moist rales in the lungs. There may be blood-tinged sputum or hemoptysis.

　　②Hemorrhagic Period: If treatment is not timely during the prodromal period, there may be a sudden pale complexion, cyanosis of the lips, restlessness, and a significant increase in respiratory and heart rate. The first heart sound may weaken or a gallop rhythm may appear. Both lungs are filled with moist rales, and most patients have varying degrees of hemoptysis.

　　③Critical Period: If the condition is not controlled, the disease can rapidly worsen within a short period (1-3 days), with symptoms such as extreme restlessness, confusion, and even coma. There may be a sound of phlegm in the throat, severe cyanosis, large amounts of fresh blood gushing from the mouth and nose (in a frothy state), which can lead to asphyxia. Heart rate may slow down, breathing may become irregular or even stop. The above process can last from a few hours to 12-24 hours. The pathogenesis of the disease may be due to the hypersensitive reaction of the body to the pathogen and its toxic substances. The reasons are: the onset is rapid and severe, recovery is also rapid, the lung lesions disappear quickly, there is no evidence of vascular rupture, massive bleeding is due to congestion, stasis, and hemorrhage; hormone treatment is effective; coagulation function is normal, and there is no DIC manifestation.

　　3. Late stage

　　After 7 to 14 days of onset, most patients recover quickly; in some cases, after early symptoms of infection and intoxication, there is no obvious organ damage in the middle stage, and they enter the late stage, which is characterized by complications in the late stage.

　　To prevent leptospiral pneumonia, it is first necessary to manage the source of infection, including rodent control, proper management of domestic animals and animal hosts, and quarantine, as well as timely detection and isolation of patients. The transmission route should be cut off, personal protection should be strengthened, and polyvalent vaccines should be used for vaccination of susceptible populations and workers exposed to infectious water. For laboratory, epidemiological staff, and workers entering newly infected areas, and for suspected infected individuals without symptoms, intramuscular injection of penicillin G 800,000 to 2,000,000 units per day for 2 to 3 days can be used as prophylactic medication.

　　The clinical manifestations of leptospiral pneumonia are complex, making early diagnosis difficult and prone to misdiagnosis and missed diagnosis. It should be combined with the characteristics of epidemiology, early clinical symptoms, and pathogenic and serological examinations for comprehensive judgment.

　　1. Laboratory examination

　　(1) Peripheral blood count The total white blood cell count and the number of neutrophils are normal or slightly elevated. The blood transaminases and bilirubin levels are increased.

　　(2) Pathogen detection The indirect fluorescent antibody staining for leptospirosis uses the black background fluorescence method to directly search under the microscope. Leptospira can be isolated from blood or cerebrospinal fluid within 10 days of onset, and the pathogen can be detected in urine in the second week. Direct microscopic examination using fluorescent antibody staining and benzidine blue staining methods has a positive rate of up to 50%, which is helpful for early diagnosis. The patient's blood or other body fluids can be inoculated into animals to isolate the pathogen for confirmation.

　　(3) Serological tests Agglutination test, enzyme-linked immunosorbent assay (ELISA) for the determination of specific antibodies have high specificity and sensitivity. Agglutinins usually appear 7 to 8 days after the onset of the disease, with a positive titer of 1:400, and can last for several months to several years. A fourfold increase in the titer of paired sera after an interval of 2 weeks is considered positive. In recent years, the disease can be diagnosed early through PCR methods.

　　2. Other auxiliary examinations

　　X-ray manifestations in mild cases include hazy reticular shadows in the lungs or disordered and thickened lung texture, with extensive lesions. Moderate cases show small dot-like or snowflake-like shadows in both lungs, with low density and blurred boundaries, which may partially merge into shadows of 2cm in size.

　　The clinical manifestations of leptospiral pneumonia are complex, making early diagnosis difficult and prone to misdiagnosis and missed diagnosis. It should be combined with the characteristics of epidemiology. Early clinical symptoms, as well as pathogenic and serological examinations, should be used for comprehensive judgment.
　　1. Laboratory examination
　　(1) Peripheral blood count The total white blood cell count and the number of neutrophils are normal or slightly elevated. The blood transaminases and bilirubin levels are increased.
　　(2) Pathogen detection The indirect fluorescent antibody staining for leptospirosis uses the black background fluorescence method to directly search under the microscope. Leptospira can be isolated from blood or cerebrospinal fluid within 10 days of onset, and the pathogen can be detected in urine in the second week. Direct microscopic examination using fluorescent antibody staining and benzidine blue staining methods has a positive rate of up to 50%, which is helpful for early diagnosis. The patient's blood or other body fluids can be inoculated into animals to isolate the pathogen for confirmation.
　　(3) Serological tests Agglutination test, enzyme-linked immunosorbent assay (ELISA) for the determination of specific antibodies have high specificity and sensitivity. Agglutinins usually appear 7 to 8 days after the onset of the disease, with a positive titer of 1:400, and can last for several months to several years. A fourfold increase in the titer of paired sera after an interval of 2 weeks is considered positive. In recent years, the disease can be diagnosed early through PCR methods.
　　2. Other auxiliary examinations
　　X-ray manifestations in mild cases include hazy reticular shadows in the lungs or disordered and thickened lung texture, with extensive lesions. Moderate cases show small dot-like or snowflake-like shadows in both lungs, with low density and blurred boundaries, which may partially merge into shadows of 2cm in size.

　　The diet for leptospirosis pneumonia patients should be high in nutrition, light, and easy to digest, and avoid spicy and greasy foods. Do not eat large fish, meat, and overly greasy foods. Pneumonia patients should not add spices such as chili, pepper, mustard, and Sichuan pepper to their diet. Quit smoking and drinking. Leptospirosis pneumonia食疗方：

　　1. Stir-fried Carp with Celery

　　Ingredients: 250 grams of carp, 50 grams of fresh celery, starch, ginger strips, garlic strips, soy sauce, sugar, vinegar, fine salt, monosodium glutamate, cooking wine, soaked chili peppers, and vegetable oil in appropriate amounts.

　　Preparation: Cut the carp into strips, cut the celery into sections, and mix soy sauce, sugar, vinegar, monosodium glutamate, cooking wine, salt, starch, and stock to make a sauce. Heat a wok on a strong fire, add oil and heat it to 5成热, add the fish strips and stir-fry until they disperse, drain the excess oil, add ginger strips and soaked chili peppers. Stir-fry the celery sections until fragrant, then add the sauce, add bright oil, and remove from heat.

　　Effects: Carp has the effects of clearing heat and detoxifying, promoting diuresis and reducing swelling, and stopping cough and relieving dyspnea; celery has the effects of calming the liver and clearing heat, removing wind and promoting diuresis, and nourishing the spirit and benefiting the Qi. The combination of carp and celery is suitable for the auxiliary treatment of acute and chronic pneumonia.

　　2. Rabbit Meat and Mushroom Shreds

　　Ingredients: 100 grams of cooked rabbit meat, 50 grams of mushrooms, 25 grams of scallion, soy sauce, vinegar, sugar, sesame oil, sesame paste, Sichuan pepper, and monosodium glutamate in appropriate amounts.

　　Preparation: Cut the cooked rabbit meat and scallion into thin strips, and cook the mushrooms. Line the bottom of the dish with scallion and mushrooms, cover with rabbit strips, and serve in a dish. Gradually disperse the sesame paste with soy sauce, mix evenly with sesame oil to make the sauce, and pour it over the rabbit strips.

　　Effects: Rabbit meat has the effects of clearing heat and detoxifying, invigorating the spleen and benefiting the Qi, removing dampness and cooling the blood, and promoting defecation; mushrooms have the effects of detoxifying and moistening, invigorating the spleen and benefiting the Qi, and removing dampness and stopping diarrhea. The combination of rabbit meat and mushrooms is suitable for the treatment of acute pneumonia.

　　3. Quail and Lily Soup

　　Ingredients: 1 quail, 25 grams of lily, ginger, scallion, monosodium glutamate, and fine salt in appropriate amounts.

　　Preparation: Kill the quail, remove the feathers, claws, and internal organs, wash and put it into boiling water for a quick blanching, then remove and cut into pieces; separate the petals of the lily, wash and set aside. Clean the ginger and scallion, beat the ginger, and cut the scallion into sections. Place a pot on a strong fire, add some water, put the quail in, bring to a boil, add the lily petals, ginger pieces, and scallion sections, then turn to a low fire to simmer until the quail is cooked, add salt and monosodium glutamate, simmer for a few minutes, and serve in a soup bowl.

　　Effects: Quail meat has the effects of nourishing the five internal organs, benefiting the liver and clearing the lung, clearing heat and promoting diuresis, and eliminating food retention and stopping diarrhea; lily has the effects of moistening the lung and stopping cough, nourishing the Yin and clearing heat, and calming the mind. The combination of quail meat and lily is suitable for acute and chronic pneumonia.

　　4. Lean Meat and Chinese Cabbage Soup

　　Ingredients: 100 grams of lean meat and 100 grams of the heart of Chinese cabbage, a little ginger, garlic, salt, monosodium glutamate, and chicken oil.

　　Preparation: Cut lean meat into thin strips, wash and slice Chinese cabbage, and put it into boiling water, then remove it when it is just cooked, rinse with cold water, drain the water and set aside. Place a pot on a strong fire, add chicken oil and heat it to 50% cooked, add garlic and stir-fry until golden yellow, then add the lean meat and stir-fry together, add fine salt, cook in soup, then add the heart of Chinese cabbage and boil, add monosodium glutamate and it is ready to eat.

　　Effects: Lean meat has the effects of invigorating the middle-jiao and benefiting the Qi, promoting saliva and moistening the intestines; Chinese cabbage is mild in nature and sweet in taste, with the effects of clearing heat and detoxifying, resolving phlegm and stopping cough, and relieving restlessness and promoting defecation. The combination of lean meat and Chinese cabbage is suitable for acute and chronic pneumonia.

　　The treatment of leptospira pneumonia in the early stage should be bed rest, high-calorie, vitamin B, and vitamin C should be provided, maintain water and electrolyte balance, and in cases of severe hemorrhage, hemostatic agents and blood transfusions should be used in a timely manner. For patients with massive pulmonary hemorrhage, the patient should be kept calm, sedatives should be used as appropriate, and first aid should be provided on the spot to minimize unexpected situations during the movement process.

　　Early application of effective antibiotics can improve the prognosis. If treatment is delayed and organ function is damaged, the therapeutic effect will decrease. Early use of penicillin can relieve fever early, shorten the course of the disease, prevent and reduce bleeding, with the initial adult dose of 400,000 units, followed by a treatment dose of 1.2 to 1.6 million units per day, administered intramuscularly in 3 to 4 doses, to avoid the Jarisch-Herxheimer reaction, and a course of 7 days or 2-4 days after the body temperature returns to normal. In severe cases, 1.6 to 2.4 million units of penicillin per day are administered intramuscularly in 4 doses, along with adrenal cortical hormones. Other antibiotics such as gentamicin, streptomycin, erythromycin, and ampicillin also have certain therapeutic effects.

　　The Jarisch-Herxheimer reaction often occurs 30 minutes after the first dose of penicillin injection, due to the release of toxins after a large number of spirochetes are killed. The symptoms include sudden chills, high fever, headache, and severe muscle pain, with increased heart rate and breathing, and may be accompanied by a decrease in blood pressure, cold extremities, and shock. These symptoms generally last for 30 minutes to 1 hour, and occasionally lead to diffuse pulmonary hemorrhage. Immediate administration of adrenal cortical hormones such as hydrocortisone 200-300mg intravenously should be given, along with antishock and sedative drugs for treatment.

　　In recent years, the synthesis of imidazole carboxylate and methazole in China has achieved good therapeutic effects for the disease, both of which can be taken orally with few side effects. The initial adult dose of imidazole carboxylate (imidazole carboxylate) is 1g, followed by 4 times a day, 0.5g each time, and the drug is discontinued 2-4 days after the body temperature returns to normal. Severe cases can be increased to 3g/d, taken in 3 doses, and reduced to 2g/d after the condition improves, with a course of 5-7 days. About 8% of cases show the Jarisch-Herxheimer reaction, but the reaction is mild and does not require special treatment. The main adverse reactions are gastrointestinal symptoms, rash, etc. The initial adult dose of methazole is 1g, followed by 3-4 times a day, 0.5g each time, with a course of 5-7 days. The drug has no Jarisch-Herxheimer reaction, and some patients may experience dizziness, intestinal sounds, and occasionally rash, dry mouth, and other reactions.