Mesenteric lymph node tuberculosis in children

Introduction to mesenteric lymph node tuberculosis in children Mesenteric lymph node tuberculosis is more common in children, may be part of the primary intestinal complex syndrome, intestinal primary tumor can be quickly absorbed, but swollen and cheese-like mesenteric lymph nodes can exist for a long time, can also be lymphatic or The blood is scattered, mostly with intrathoracic lymph node tuberculosis or whole body miliary tuberculosis. Sometimes mesenteric lymph node tuberculosis is the main manifestation, while other areas of tuberculosis are not obvious, in this case should be diagnosed as a separate case. basic knowledge The proportion of illness: 0.001% Susceptible people: children Mode of infection: respiratory tract spread digestive tract spread Complications: diarrhea, abdominal pain, ascites, edema, intestinal obstruction

Pediatric mesenteric lymph node tuberculosis

(1) Causes of the disease

There are 4 types of Mycobacterium tuberculosis: human, bovine, bird and mouse, while human pathogenic bacteria are human tuberculosis and bovine tuberculosis. Most of the children's tuberculosis in China is caused by human tuberculosis, tubercle bacillus Strong resistance, in addition to acid resistance, alkali resistance, alcohol resistance, cold, heat, dry, light and chemical substances have strong tolerance, damp heat has strong bactericidal power against tuberculosis, At 65 ° C for 30 min, 70 ° C for 10 min, 80 ° C for 5 min to kill, dry heat sterilization is poor, dry heat 100 ° C takes more than 20 minutes to kill, so dry heat sterilization, temperature needs high, time needs to be long, inside The tuberculosis bacteria are killed within 2 hours of direct sunlight, while the ultraviolet light only takes 10 minutes. On the contrary, it can survive for several months in the dark. The tuberculosis bacteria in the sputum use 5% carbolic acid (phenol) or 20% bleaching powder. For liquid disinfection, it takes 24 hours to take effect.

(two) pathogenesis

The 137 cases of children died of tuberculosis in Beijing Children's Hospital found that about 30% of mesenteric lymph node tuberculosis, the number and size of lymph nodes vary, easy to fuse into clumps, have cheese-like changes, and sometimes with nearby tissues and organs such as intestinal The peritoneum and the greater omentum are stuck together, and even form a huge mass like a fist. The necrotic liquefaction of the cheese-like substance can be broken into the abdominal cavity, the intestinal lumen, or discharged through the abdominal wall. After the disease is cured, it can be scattered or widely seen. Calcification.

Pediatric mesenteric lymph node tuberculosis prevention

1. Control the source of infection and reduce the chance of infection

Tuberculosis smear-positive patients are the main source of tuberculosis in children. Early detection and rational treatment of smear-positive tuberculosis patients is a fundamental measure to prevent tuberculosis in children. Infants and young children suffer from active tuberculosis, and their family members should do a detailed examination (photographing chest) , PPD, etc.), regular physical examinations for primary and child care institutions, timely detection and isolation of infectious sources, can effectively reduce the chance of tuberculosis infection in children.

2. Popularization of BCG vaccination

Practice has proved that vaccination with BCG is an effective measure to prevent tuberculosis in children. BCG was invented by French physicians Calmette and Guerin in 1921, so it is also called BCG. China has vaccinated BCG in the neonatal period and inoculated BCG in the upper left arm of the left upper arm. Intradermal injection, the dose is 0.05mg / time, the scratch method is rarely used, the Ministry of Health notified in 1997 to cancel the 7-year-old and 12-year-old BCG re-integration plan, but if necessary, the child with negative age test Multiple cropping can be given, and BCG vaccine can be injected in the same day as the hepatitis B vaccine.

Contraindications to vaccination with BCG: positive lignin response; patients with eczema or skin disease; recovery period of acute infectious disease (1 month); congenital thymic dysplasia or severe combined immunodeficiency disease.

3. Prophylactic chemotherapy

Mainly used for the following objects:

(1) Infants under the age of 3 have not been vaccinated with BCG and have a positive test.

(2) Close contact with patients with open tuberculosis (multiple family members).

(3) The sputum test has recently changed from negative to positive.

(4) The sputum test is a strong positive responder.

(5) Children with positive serotonin test need to use adrenocortical hormone or other immunosuppressive agents for a longer period of time.

The drug used for chemopreventive drugs is mainly isoniazid, the dose is 10mg/(kg·d), the course of treatment is 6-9 months, the newborns of the newly born tuberculosis parents under the age of 6 and the newborns born to the tuberculosis women, regardless of the knot If the results of the test are all the same, the isoniazid should be given. The dose is the same as above. After 3 months of administration, the test is performed. If it is positive, the isoniazid is continued for 9 months; if the test is negative (<5mm) ), then stop the isoniazid.

Anti-HIV-positive children with a history of tuberculosis should receive isoniazid for 12 months regardless of the outcome of the nodule test.

If the tuberculosis patient contacted by children is resistant to isoniazid, the chemotherapeutic drug should be changed to rifampicin, 15mg/(kg·d), 6-9 months; if it is resistant to isoniazid and resistant to rifampicin, It is recommended to give pyrazinamide plus ofloxacin for 6 to 9 months, or pyrazinamide plus ethambutol for 6 to 9 months.

Pediatric mesenteric lymph node tuberculosis complications Complications diarrhea abdominal pain ascites edema intestinal obstruction

Cause diarrhea, abdominal pain, swollen lymph nodes to press the portal vein to block the reflux, can produce ascites and abdominal wall vein dilatation, compression of the inferior vena cava can cause lower extremity edema, compression of the chest tube can cause chylothorax ascites, compression of the pyloric can cause pyloric stenosis, oppression of the intestine Can cause incomplete intestinal obstruction.

Pediatric mesenteric lymph node tuberculosis symptoms Common symptoms constipation fatigue nausea edema weight loss appetite loss lymph node enlargement abdominal distension ascites low fever

The main symptoms are general symptoms of tuberculosis and local symptoms. The symptoms of chronic poisoning are long-term irregular low fever, loss of appetite, weight loss, fatigue, sleep disturbance, emotional instability, etc. Local gastrointestinal symptoms include nausea, vomiting, diarrhea, constipation, Abdominal distension, abdominal pain, etc., of which abdominal pain is the most common, abdominal pain can be a frequent persistent mild dull pain; but more similar to colic, abdominal pain is mostly located in the umbilicus or deep in the abdomen, mostly in the left upper abdomen or right lower abdomen, so there is Misdiagnosed as acute appendicitis for surgery, visual examination and palpation can be seen in the abdominal wall mild tension and bulging, palpation can find typical tender points, often in the right lower abdomen is equivalent to the appendicitis point, or in the left upper abdomen with the equivalent 2 lumbar vertebrae level is the mesenteric root, sometimes can touch one or more swollen lymph nodes, small as broad beans, can be like hand fist, there is tenderness, palpation should be carried out in the early morning on an empty stomach to clean the enema, swollen lymph nodes sometimes Causes compression: compression of the portal vein causes obstruction of reflux, resulting in ascites and abdominal wall vein dilatation, compression of the inferior vena cava can cause lower extremity edema, compression of the thoracic duct can cause chylothorax ascites Helicobacter pyloric stenosis can cause compression; compression can cause incomplete intestinal obstruction. In addition, children are often white or yellow thick tongue, showing poor digestion, sometimes highly allergic, such as recurrent herpes conjunctivitis.

Examination of mesenteric lymph node tuberculosis in children

1. Smear and culture

The detection of acid-fast bacilli from the serous cavity is an important means of diagnosing tuberculosis, but the positive rate is low, only 20% to 30%. In addition, the specimens can be inoculated into guinea pigs for tuberculosis culture, and the growth of tuberculosis is slow, 4-6 Typical pathological changes occurred only after the week. In recent years, the Bactec460 rapid culture identification system was applied. The 7H12 mycobacterial medium with radioactive nutrients (14C palmitic acid) was used as the substrate. The tuberculosis growth period can be shortened to 1-3 weeks. Mycobacterium tuberculosis takes 9 days to identify Mycobacterium tuberculosis and non-tuberculous mycobacteria. The drug sensitivity test takes another 3 to 5 days. In 1991, the dual-phase culture technique Rocheseptichek-AFB system was used to rapidly isolate Mycobacterium tuberculosis, which can be produced in 2 to 4 weeks. It is reported that the acid-fast bacteria L-type bacteria is a variation of cell and colony morphology, which is difficult to culture by conventional methods, and acid-fast staining is not easy to be found. Domestically applied modified pancreatic soy protein agar medium (TSA-L), fast peptone Agar bovine serum medium and sheep blood culture medium were used to isolate and culture L-type tuberculosis. In 1998, 260 cases of retreatment were performed, and L-type tubercle bacilli were cultured in refractory tuberculosis patients, with a positive rate of 29.6%.

2. Mycobacterium tuberculosis antibody detection

In the past, antibodies such as natural antigen PPD (PPD-IgG, PPD-IgM) were used, and the sensitivity and specificity were poor. For more than ten years, the purified or semi-purified antigen of Mycobacterium tuberculosis was prepared to make Mycobacterium tuberculosis specific antibody. The detection has made significant progress. The commonly used antigens are semi-purified Mycobacterium tuberculosis antigen 5, antigen 6, AOO antigen; semi-purified glycolipid antigens such as glycolipids SAGA1, B1 and C, phenol glycolipid (PGL-Tb1), lipid Arabinose (LAM) antigen, thiolipid (SL-I, SL-IV), TB-C-1 antigen, lipopolysaccharide (LPS), etc.; purified antigen has tuberculosis protein antigen (38kDa, 30/31kDa, 71kDa, 45kDa, 14kDa, 19kD3a Mycobacterium tuberculosis antigen), recombinant 38kDa tuberculosis protein.

(1) Enzyme-linked immunosorbent assay (ELISA): used to detect anti-tuberculosis antibodies in serum, cerebrospinal fluid and serosal fluid of tuberculosis patients, which can be used as an auxiliary diagnostic index. The sensitivity of ELISA for semi-purified antigen is 65%~ 85%, sensitivity to sputum smear-negative tuberculosis is 53% to 62%, sensitivity to extrapulmonary tuberculosis is 34% to 40%, specificity is 95%, ELISA detection antibody using 38kDa purified antigen, sensitivity is 73 %, sensitivity to tuberculosis-negative tuberculosis was 70%, specificity was 98%. ELISA was used to detect specific antibodies in cerebrospinal fluid of patients with tuberculous meningitis with sensitivity of 70% and specificity of 100%.

(2) Enzyme-linked immunosorbent electrophoresis (ELIEP): an immunological technique that combines ELISA with electrophoresis and is a serological method for the diagnosis of various tuberculosis.

3. Mycobacterium tuberculosis antigen detection

Detection of Mycobacterium tuberculosis antigen in body fluid by ELISA, latex agglutination test, reverse passive hemagglutination test, etc., such as detection of Mycobacterium tuberculosis 34kDa cytoplasmic protein (antigen 5) in cerebrospinal fluid by ELISA for diagnosis of tuberculous meningitis, sensitivity 80%, specificity 100%, double-antibody sandwich ELISA method for detection of cerebrospinal fluid, ascites, pleural effusion of Mycobacterium tuberculosis 43kDa immunodominant antigen, sensitivity 100%, specificity 96%, the application of synergistic agglutination test determination of lipid arabic nectar Glycan antigen, sensitivity 85%90%, specificity 93%, detection of Mycobacterium tuberculosis antigen by Western blotting, sensitivity 89.7%, specificity 95.7%, extrapulmonary tuberculosis, sputum smear negative tuberculosis The disease is diagnostic.

4. Determination of structural components of tubercle bacilli

Gas chromatography-mass spectrometry was used to detect the bacterial structural components of Mycobacterium tuberculosis in serum and cerebrospinal fluid, namely tuberculosis stearic acid (10-methyloctadecanoic acid), which has high specificity and sensitivity. The carboxylic acid of Mycobacterium tuberculosis in cerebrospinal fluid was determined by pulsed electron capture gas chromatography with sensitivity of 95% and specificity of 91%, but the equipment and technology required were complicated and expensive.

5. Molecular biology examination

(1) DNA probe molecular hybridization: DNA probe method is not sensitive to the detection of clinical specimens. The number of bacteria in the specimen is 10,000/ml, and the gene probe technology labeled with acridinium ester and The chemiluminescence measurement system replaces the enzyme standard color development system, can improve sensitivity, can identify a variety of mycobacteria, rapidly detect Mycobacterium tuberculosis, and use bacterial luciferase to detect hybridization signals, which can improve sensitivity by 100 times.

(2) Polymerase chain reaction (PCR): selectively amplifying a gene fragment encoding the MPB64 protein specific for Mycobacterium tuberculosis complex, capable of amplifying this extremely small amount of DNA sample by several hundred thousand times or more for several hours The results are fast, sensitive and specific, but they are more likely to produce false positive and false negative results. PCR amplification of Mycobacterium tuberculosis specific insertion sequence IS6110, detection of sputum specimens, positive rate of 93%, false positive rate of 2.9%, Domestic horses use nested PCR to determine pathological specimens, sputum specimens and other Mycobacterium tuberculosis DNA, no false positives. Some people used nested PCR to detect the specific repeat insertion sequence IS6110 of Mycobacterium tuberculosis in peripheral blood mononuclear cells of tuberculosis patients, the positive rate was 64%. , 32% higher than sputum smear and 35% sputum culture, (3) DNA fingerprinting technique: analysis of the specific band spectrum of restriction endonuclease fragment of bacterial chromosome, such as DNA insertion sequence IS6110, to identify strains, Used in epidemiological studies.

(4) Detection of drug resistance genes in Mycobacterium tuberculosis: PCR-SSCP analysis, PCR-restriction fragment length polymorphism (PCR-RFLP) analysis, PCR-DNA sequencing, and tuberculosis Bacillus resistance gene.

(5) Gene chip technology: Many DNA probes are fixed on a solid phase carrier in a certain order and arrangement to form a probe matrix, which hybridizes with the DNA to be tested, and simultaneously obtains a large amount of genetic information. A 16SrRNA gene chip for the determination of mycobacterial interspecies polymorphism was developed to identify Mycobacterium tuberculosis and other non-tuberculous mycobacteria, and the other was a gene chip for analyzing the genotype of drug-resistant tuberculosis strain rpoB for analysis of rpoB gene. mutation.

6. ESR

The erythrocyte sedimentation rate during the active period of tuberculosis can be accelerated. After the anti-tuberculosis treatment, the erythrocyte sedimentation rate gradually decreases. It means that there is active disease, and the erythrocyte sedimentation rate is not specific. The erythrocyte sedimentation rate cannot exclude active tuberculosis.

Multiple facial calcifications in the X-ray plain film are helpful for the diagnosis. In the differential diagnosis, it should be distinguished from mesenteric lymphadenitis, acute and chronic appendicitis, intestinal obstruction, etc. If there is a huge mass in the abdominal cavity, it should be associated with lymphosarcoma. Identification of neurofibromatosis, B-ultra visible enlarged lymph nodes or ascites.

Diagnosis and diagnosis of mesenteric lymph node tuberculosis in children

diagnosis

Diagnosis can be based on the history of tuberculosis exposure, positive test results, clinical symptoms, deep palpation of the abdomen and rectal exploration. Abdominal X-ray films can be found in calcifications. In the process of chronic evolution and repeated deterioration of the disease, it is helpful for diagnosis. .

Differential diagnosis

Differential diagnosis should consider chronic or acute appendicitis. According to our treatment of mesenteric lymph node tuberculosis, we have been misdiagnosed as appendicitis, even misdiagnosed for 2 to 3 years, followed by hepatitis, non-specific mesenteric lymphadenitis, echinococcosis , tsutsugamushi, etc., in addition, even need to identify the stomach and duodenal ulcer, cholecystitis, abdominal lymph nodes should be differentiated from limited ileitis, lymphosarcoma and other abdominal tumors.

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