Tropical splenomegaly syndrome in children

　　1, Etiology

　　The onset of this disease is an immunoglobulin metabolism disorder caused by malaria infection. The occurrence of this disease has genetic factors.

　　2, Pathogenesis

　　Tropical splenomegaly represents an abnormal host response to parasites, especially malaria parasites, which is basically a disease of immunoglobulin metabolism disorder. Under long-term antimalarial drug treatment, the spleen shrinks, IgM decreases, therefore, it is believed to be related to malaria infection.

　　The complement C3 in the patient's serum is low, the appearance of serum anticomplement activity, and the presence of cryoglobulin suggest that this syndrome is an immunocomplex disease. Immunofluorescence methods can detect IgM, as well as IgG and C3, on Kupffer cells and macrophages in the liver sinusoids. Due to the presence of recurrent and persistent antigenemia in high malaria areas, an excessive amount of immune complexes is produced, and macrophages need many years to clear these complexes, causing hyperplasia of reticular endothelial cells in the spleen and liver, leading to organ enlargement. Fakunle et al. (1976) believe that the dysregulation of T lymphocytes in the production of immunoglobulins, especially IgM, is the main cause of this syndrome. Fakunle et al. (1978) found that the ratio of blood T lymphocytes decreased in patients with this syndrome, while the ratio of B lymphocytes increased, and the ratio of T cells in the splenic puncture fluid increased. Since the occurrence of this disease has a racial and familial nature, there may be genetic factors involved in the regulation of immunoglobulins.

　　This syndrome may have symptoms such as splenic hyperactivity, hemolysis, and portal hypertension. There may be rectal prolapse, gastroptosis, chronic diarrhea, and a decrease in appetite, bloating after eating, a feeling of descent in the lower abdomen, fatigue, shortness of breath, fatigue, and yellowish complexion. The cause is that the spleen fails to rise, so there is bloating after eating, or diarrhea and abdominal descent, as well as the influence on other visceral organs and prolapse. Deficiency of the spleen and stomach leads to the failure of transportation and transformation, deficiency of Qi and blood, resulting in a decrease in appetite, fatigue, and a yellowish complexion.

　　The onset age of this syndrome ranges from 8 to 65 years old, rarely occurring before the age of 8. The clinical manifestations include low fever, anemia (hemoglobin is mostly between 60 to 100g/L), enlargement of the liver and spleen, with the latter being particularly prominent. The bone marrow shows obvious hyperplasia. Anemia is mainly due to an increase in the storage of blood cells in the spleen, splenic hyperactivity, increased blood volume, dilution of blood, and recurrent gastrointestinal bleeding. The lifespan of red blood cells is slightly shortened, but it can急剧降低 during pregnancy. Some cases may show hemolysis and portal hypertension.

　　The prevention of malaria refers to the protection of susceptible populations. It includes individual prevention and collective prevention. Individual prevention is the protective measures taken by residents of malaria areas or those who enter the malaria area for a short period of time to prevent mosquito bites, prevent the onset of the disease, or alleviate clinical symptoms. Collective prevention is for populations in high malaria areas, outbreak areas, or those entering the malaria area for a long-term stay in large numbers. In addition to including the purposes of individual prevention, it also aims to prevent transmission. Protective measures should be selected based on the weak links in the transmission routes, being economic, effective, and easily accepted by the masses. Prevention measures include mosquito control, drug prevention, or vaccine prevention.

　　1. Blood Test

　　Peripheral blood smear shows anemia, with a significant decrease in hemoglobin, mostly between 60-100g/L, platelets may be reduced, and hemolysis may occur.

　　2. Immune Function Examination

　　Increased IgM, lower complement C3, presence of serum anti-complement activity, and the existence of cold agglutinins, decreased proportion of T lymphocytes, and increased proportion of B lymphocytes.

　　3. Pathological Examination

　　Fluorescence methods can detect IgM as well as IgG and C3 on the Kupffer cells and macrophages in the sinusoids of the liver, and the proportion of T cells in the splenic puncture fluid increases.

　　4. Bone Marrow Examination

　　The bone marrow shows obvious hyperplasia.

　　Prevent mosquito bites, especially in summer. Because mosquitoes are very likely to carry viruses or bacteria, transferring them from one person to another. Keep the home clean and pay attention to indoor ventilation, and spray insect repellent frequently.

　　1. Treatment

　　After long-term antimalarial chemotherapy, the condition may improve, but it is slow and often recurs after discontinuation of medication. Chloroquine and long-acting chloroquine, among others, have similar efficacy. Patients who do not respond may develop lymphoma or lymphocytic leukemia, and the lymphocytes of these patients have a poor response to phytohemagglutinin (PHA), which helps in early identification.

　　Splenectomy is required when there is hypersplenism, and the serum IgM decreases, and hematological changes improve after surgery, but if antimalarial treatment is not performed, the liver still swells, and the histological changes do not improve.

　　2. Prognosis

　　The prognosis of this condition, according to the results of a 6-year follow-up of 75 patients by Crane et al. (1972) in New Guinea, is a mortality rate of 29% to 57%, and it is proportional to the degree of splenomegaly.