Infectious mononucleosis in children

Introduction to infectious mononucleosis in children Infectious mononucleosis (flyer) is an acute infectious disease caused by EB virus that mainly affects the lymphatic system. The clinical manifestations vary widely. Common fever, pharyngitis, lymph nodes and hepatosplenomegaly, blood. The number of lymphocytes is increased and there is a heterotypic lymph. Epstein-Barr virus antibodies can be detected in serum. basic knowledge The proportion of illness: 0.02% Susceptible people: children Mode of infection: droplet spread Complications: acute nephritis Myocarditis Hemolytic anemia Thrombocytopenic purpura Aplastic anemia

Causes of infectious mononucleosis in children

Causes:

Epstein-Barr virus is the first to be found in African children's lymphoma (Burkitt's lymphoma) cell culture by Epstein and Barr. It belongs to the herpes virus group. The morphological structure under the electron microscope is the same as that of other viruses in this group, but the antigenicity is different. The disease is caused by the EB virus.

Pathogenesis:

Epstein-Barr virus enters the susceptible person from the mouth, first replicates in the B lymphocytes of the pharyngeal tonsil ring, and then infects other parts of the B lymphocytes by viremia or disseminated B lymphocytes, and the virus replicates to cause B lymphocytes. The death, virus particles and viruses determine that the antigen is released, stimulating the body to cause an immune response. In the early stage of the disease, viral replication in some infected B cells is inhibited and becomes a B cell with an Epstein-Barr virus genome. Such B cells can be T killer cells recognize that T killer cells proliferate due to stimulation, resulting in systemic lymphadenopathy, internal organs infiltration, B lymphocytes carrying Epstein-Barr virus genome are eliminated by T cells, and T cells are no longer stimulated by antigen. Reduction, as well as the appearance of neutralizing antibodies in the body and the reduction of B cells in the oropharyngeal replication virus by T cells, so that the disease is controlled, and some patients can still replicate in the oropharynx after a period of recovery or even life, intermittent detoxification and Lead to the existence of certain antibodies, abnormal blood lymphocytes are B cells infected with Epstein-Barr virus and stimulated T cells, B cells than T Cells first appeared, with a ratio of the variation of the course of the disease.

Pediatric infectious mononucleosis prevention

The disease is not contagious, but it should be quarantined on the spot. There are no effective preventive measures for this disease. In the acute phase, the children should be isolated from the respiratory tract. The oral secretions and their pollutants should be strictly disinfected. It is recommended to use bleaching powder and chloramine. Or boiled and disinfected, but it is also considered that it is not necessary to isolate the patient. The viremia may be several months after the patient recovers. Therefore, if the blood donor is a blood donor, the blood donation period must be extended to at least 6 months after the onset of the disease. There is currently no vaccine.

Pediatric infectious mononucleosis complications Complications acute nephritis myocarditis hemolytic anemia thrombocytopenic purpura aplastic anemia

About 30% of patients can be complicated by pharyngeal hemolytic streptococcal infection, the incidence of acute nephritis can be as high as 13%, clinical manifestations like general nephritis, about 6% of patients with myocarditis.

1. Hemolytic anemia: The incidence rate can be 3%. Most patients with autoimmune hemolytic anemia have positive Coombs test, and the concentration of cold agglutinin increases, usually extravascular hemolysis.

2. Thrombocytopenic purpura: associated with platelet destruction in the spleen and increased peripheral platelet destruction, and evidence of the presence of platelet antibodies in some cases.

3. Aplastic anemia.

4. Neurological diseases: manifestations can be varied, meningoencephalitis can occur headache, fever, paralysis, mental disorders or even coma, or neck stiffness, convulsions, meningeal irritation positive, ataxia and stiffness, etc., or Bell, Transverse myelitis, Guillain-Barre syndrome, etc., severe cases can lead to death, most patients have no neurological manifestations, but cerebrospinal fluid examination, 15% of children may have increased protein or cell number, the number of cells increased to a single Caused by nuclear cell infiltration.

5. spleen rupture: the incidence of spleen rupture is about 0.2%, usually more common in the disease within 10 to 21 days, the action should be gentle when touching the spleen to avoid rupture of the spleen, occasionally spleen rupture occurs in the sick child, when the spleen ruptures Moderate or severe pain may occur under the left rib and radiate to the left shoulder. Peripheral circulatory failure may occur when the spleen ruptures.

6. In 1966, Old used immunodiffusion to reveal the serological relationship between EBV and nasopharyngeal carcinoma. In addition, other tumors associated with EB virus infection were malignant lymphoma, oral gland tumor and thymoma.

7. Others: Other rare complications include interstitial pneumonia, glomerulonephritis, pancreatitis, myocarditis, pericarditis, etc., and immune disorders may occur. It is reported that in addition to heterophilic antibodies, serological tests may be performed in patients with this disease. Anti-nuclear antibodies, rheumatoid factor, and acquired agammaglobulinemia can also be found. Waldeyer lymph node ring lymphoid tissue hyperplasia can cause airway obstruction, severe life-threatening, and otitis media, rhinitis, eyelids or paralysis Edema can occur in the week.

Symptoms of infectious mononucleosis in children Common symptoms Myalgia low fever Lymph node swelling Scarlet fever rash dysphagia Difficulty swallowing conjunctival conjunctival hyperemia Liver splenomegaly abdominal pain

Epstein-Barr virus is transmitted through saliva droplets, also known as "kissing disease". The incubation period is 30 to 50 days in adolescents, and may be shorter in children, most of which are 9 days (5 to 15 days). In the cold season, the number of cases may increase, and occasional epidemics occur.

General symptoms

Acute or insidious onset, fatigue, fever and myalgia, fever can be high or low, lasting 1 to 2 weeks after retreating or receding, also lasting 3 to 4 weeks or continuing low fever for 3 months, some patients With slow pulse, similar to typhoid.

2. Nasopharyngeal manifestations

The most common is the pharyngeal isthmus, the sacral congestion, the tonsil congestion and swelling, and even a few may have difficulty breathing or difficulty swallowing. The surface of the tonsils may have thick frosty exudates, and a few have pseudomembrane formation.

3. Lymph node enlargement

Is one of the main manifestations of this disease, more common in the posterior cervical lymph nodes, but the superficial lymph nodes can be involved, lymph nodes are generally light, moderately enlarged, diameter is more than 3 ~ 4cm or more are rare, moderate hardness, dispersion without adhesion, The tenderness is not obvious, and most of the swollen lymph nodes need to resolve within a few weeks after the heat retreat. Mesenteric lymphadenopathy can cause abdominal pain and other symptoms.

4. Hepatosplenomegaly

About half of the patients may have increased liver and spleen, and the degree of swelling may vary. As the body temperature decreases, the condition may be reduced and may be accompanied by pain or tenderness in the spleen area. Most of them are accompanied by one or more abnormal liver functions, and some cases have jaundice.

5. Skin mucosa performance

A small number of cases have morphological rashes 4 to 10 days after the disease, which may be papules, maculopapular rashes, similar to measles or scarlet fever-like rashes. Some patients have needle-like bleeding points at the junction of soft and soft sputum at the junction of the mouth, and the ocular membrane is congested or Eyelid edema, in addition to the above typical symptoms, a considerable number of children with EB virus infection can often be asymptomatic or mild symptoms, due to the disease can be affected by various organs of the body, a large number of pediatric patients, its clinical symptoms change, performance Diverse, clinicians are sometimes divided into heart type, nerve type, hepatitis type, nephritis type, pneumonia type, gastrointestinal type, etc. according to the clinical manifestations of patients.

Pediatric infectious mononucleosis examination

Blood picture

The number of white blood cells is normal or slightly increased, mostly below 20 × 109 / L, a small number can also be reduced, early neutrophils increased, after lymphocytes increased, up to 60% ~ 97%, atypical lymphocytes can be 4 after disease It starts to appear in ~5 days, peaks in 7-10 days, and a few chronic diseases can still be detected in a few weeks. In pediatric cases, the younger the age (especially under 5 years old), the higher the positive rate of atypical lymphocytes. Heterotypic lymphocytes can be divided into 3 types according to Downey classification:

(1) Type I (vacuum type): medium cell size, irregular edges, nuclear maturation, eccentricity, elliptical shape, kidney shape or lobulation, pale area around the nucleus, deep staining of cytoplasm, containing vacuoles, There may be a small amount of yilimine blue granules.

(2) Type II (irregular): large cells, irregular shape, rounded nucleus, coarse nuclear chromatin, mild cytoplasmic basal, no or very few vacuoles, sometimes resembling a normal single nucleus .

(3) Type III (infancy type): similar to the vacuole type, but the nuclear form is naive, the chromatin is fine, and the nucleolus is 1 or 2 distinct, resembling a naive cell.

2. Bone marrow

Lymphoid cells are normal or increased, and there may be atypical lymphocytes, but not as many as seen in the blood, and the original lymphocytes do not increase.

3. Immunological test

(1) Heterophilic antibodies; mainly sheep and horse erythrocyte lectin, belonging to IgM, appearing earlier, reaching a peak within 3 to 4 weeks, the positive rate of heterophilic agglutination test is related to age, mostly negative under 5 years old, with age Growth, the positive rate has an upward trend. When positive, it must be done in bovine red blood cells or guinea pig kidney adsorption test to distinguish it from normal serum, serum disease, leukemia, Hodgkin's disease and tuberculosis. The leaflet patient heterologous agglutination test can be used by bovine red blood cells. The heterophilic lectin adsorbed by the guinea pig kidney, normal human, serum disease and other patients can be negatively adsorbed by bovine erythrocytes and guinea pig kidneys. Monospot test: stable horse with formaldehyde Red blood cells replace sheep red blood cells in the heterophilic agglutination test, which can improve sensitivity and specificity, and the positive rate can reach more than 90%. The method is simple.

(2) EB virus-specific antibody assay: 1 shell antigen (VCA) antibody, its IgM part increased at an early stage, disappeared after several weeks; IgG part reached a peak at 2 weeks, existed for life, but the titer was earlier Low, the positive rate of both is 100%, 2 membrane antigen (MA) antibody, reaching the peak time later, but long-term existence, the titer is unchanged, 3 early antigen (EA) antibody, its diffuse part (D) antibody 70% to 80% of patients with acute phase temporarily increase for 3 to 6 months, limiting part of (R) antibodies in the later stages of the disease, lasting 2 months to 3 years, may be related to disease prolongation and recurrence, 4 Nuclear antigen (NA) antibodies, the non-complement binding part can be higher soon after onset, and the complement binding part should appear after 1 to 2 months, but all patients have this antibody for a long time, the positive rate is 100%. VCA-IgM is often used as a diagnosis in clinical practice.

(3) Others: Autoantibodies are mainly IgM, which can occur briefly in the acute phase, and the titer is very low. The most important anti-i antibody in clinical practice, such as increased titer, can cause autoimmune hemolytic anemia, and others still have classes. Rheumatoid factor, anti-nuclear antibody, anti-smooth muscle antibody, lymphocyte toxicity antibody, etc., X-ray, B-ultrasound, electrocardiogram, EEG, etc., can be found in liver, spleen, lymph nodes, cervical lymphadenopathy Common, under the armpit and groin.

Diagnosis and diagnosis of infectious mononucleosis in children

diagnosis

The disease is more common, and sometimes the clinical manifestations are diverse, so it is necessary to improve the vigilance and awareness of the disease, in order to prevent missed diagnosis or misdiagnosis, the young children are prone to atypical lymphocytes, so you should look carefully when observing the blood, such as different lymph> 10 % should be highly suspected of this disease, the positive rate of heterophilic agglutination test of this disease is about 70%, and it is easy to be negative under 5 years old, so the diagnosis depends on the EB virus antibody determination.

Differential diagnosis

Differential diagnosis of other viral infections, leukemia, suppurative tonsillitis, diphtheria, pertussis, lymphoma, malignant histiocytosis, infectious hepatitis, collagen disease, typhoid, etc., because the clinical manifestations of this disease are complex, it is in difficult cases One of the diseases that should be identified is often mentioned during the discussion. The disease should be identified with the following diseases:

1. Malignant lymphoma and acute lymphocytic leukemia

Because of the disease, fever, liver and spleen, swollen lymph nodes, peripheral white blood cell count can sometimes be as high as 50 × 109 / L, so it should be differentiated from lymphoma and lymphocytic leukemia, the latter two lymph nodes will not shrink by themselves The lymphadenopathy of children with infectious mononucleosis can resolve within a few weeks. If necessary, lymph node biopsy can be identified. The patient should be routinely examined for bone marrow smears to exclude leukemia. In addition, the disease is often There is angina, the tonsil tonsils and pseudomembrane, can also be differentiated from lymphoma and leukemia.

2. Streptococcal pharyngitis

Because of the manifestations of angina and fever, it should be differentiated. When streptococcal infection, the peripheral blood showed an increase in the total number of white blood cells, increased neutrophils, and had a good effect on antibiotic treatment such as penicillin.

3. Cytomegalovirus infection

The clinical manifestations of cytomegalovirus disease resemble this disease. The liver and splenomegaly are caused by the action of the virus on the target organ cells. Infectious mononucleosis is associated with lymphocyte proliferation, and the cytomegalovirus disease is swallowed. Pain and neck lymphadenopathy are rare. There is no heterophilic lectin and EB virus antibody in serum. The diagnosis depends on virus isolation and specific antibody determination. The disease also needs to be differentiated from acute lymphocytic leukemia. Bone marrow cytology examination There is a diagnosis value, the disease needs to be differentiated from acute infectious lymphocytosis in children, the latter is more common in young children, most of them have upper respiratory symptoms, lymph nodes are rare, no splenomegaly; the total number of white blood cells is increased, mainly mature lymph Cells, abnormal blood picture can be maintained for 4 to 5 weeks; heterophilic agglutination test is negative, no Epstein-Barr virus antibody appears in the serum, in addition, the disease should be differentiated from exudative tonsillitis caused by hepatitis A virus and streptococcus, infection Sexual mononucleosis can coexist with congenital cytomegalovirus infection. The disease has fever, liver and spleen, swollen lymph nodes, etc., and EB disease can be found. Toxic antibodies.

4. Infectious hepatitis

Hepatitis A or hepatitis B can be diagnosed by serological examination.

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