Thought the child was just having a rash, but it turns out it's this dreaded disease

time:2023-02-07 author:Make one's mouth water
Thought the child was just having a rash, but it turns out it's this dreaded disease

*For medical professionals reading and reference only Acute hemolytic anemia. With methylprednisolone and gamma globulin infusions, the child's hemoglobin (HGB) gradually rose. So why do children have hemolysis? The doctor did a lot of tests to find the cause of the child, and finally found that the child was positive for parvovirus B19-IgM antibody. The father of the child also recalled that the child had a red rash on his cheeks after the fever, but thought that the child was just a common rash and did not care. In the end, doctors believed that Dongdong was secondary autoimmune hemolytic anemia (AIHA) caused by parvovirus B19 infection. Knowledge link: Human parvovirus B19 (hereinafter referred to as B19) is a small DNA virus, which is the smallest and simple in structure among DNA viruses. B19 is mainly transmitted through the respiratory tract, but can also be transmitted through blood and blood products. Young children are often infected with B19. After contracting the virus, some children have pink cheeks that look like apples, which is medically known as erythema contagiosum. B19 can cause joint pain and arthritis in adults and older children. Children with immune deficiency are prone to chronic B19 infection, mainly manifested as chronic anemia. The definition of hemolytic anemia First let's understand what is hemolytic anemia. Hemolysis is a process in which red blood cells are destroyed and their lifespan is shortened. Bone marrow has 6-8 times the compensatory ability of normal hematopoiesis. When hemolysis occurs and bone marrow can compensate, there is no anemia, which is called hemolytic state. When hemolysis exceeds the compensatory capacity of the bone marrow, the resulting anemia is hemolytic anemia. The pathogenesis of hemolytic anemia is divided into two categories: internal abnormality of red blood cells and external factors, as shown in Table 1. Table 1 Pathogenesis of hemolytic anemia Next, we will focus on the AIHA in this case: it is due to the immune dysfunction of the body, the production of erythrocyte autoantibodies, and the increase in erythrocyte destruction mediated by antibodies or complement pathways, exceeding the bone marrow erythrocyte compensation A general term for a group of hemolytic anemias caused by proliferative capacity. The etiology of AIHA is divided into primary and secondary AIHA based on whether there is an underlying disease that causes hemolysis. (1) Primary AIHA: There is no definite underlying disease that can cause hemolysis, accounting for 40%-50% of AIHA cases in children, mostly caused by warm antibody autoantibodies. (2) Secondary AIHA: There are underlying diseases that can cause hemolysis, and the common causes of secondary hemolysis are shown in Table 2 below. Table 2 Common causes of secondary hemolytic anemia (can be enlarged) Classification of AIHA paroxysmal cold hemoglobinuria). (1) Warm antibody AIHA: It is the most common type of primary AIHA in children, accounting for 60%-90%, and the antibody type is often IgG. These antibodies preferentially bind erythrocytes at 37°C, resulting in extravascular hemolysis (mainly in the spleen), followed by anemia, jaundice, and occasionally splenomegaly. (2) Cold agglutinin disease (CAD): CAD in children is relatively rare, accounting for about 10%, and most often occurs after Mycoplasma pneumoniae or Epstein-Barr virus infection. CAD-related IgM autoantibodies bind to erythrocyte I/i antigens at low temperature (0°C-4°C) and fix complement, thereby mediating intravascular hemolysis. (3) Paroxysmal cold hemoglobinuria (PCH): It is an AIHA that occurs almost only in children, most often after viral infection. PCH is characterized by IgG autoantibodies that bind more readily at low temperatures, effectively fix complement, and cause intravascular hemolysis upon rewarming. Clinical manifestations of AIHA Most children have symptoms and signs related to anemia, such as fatigue, shortness of breath, dizziness, and pallor. If anemia develops slowly, the cardiovascular system can compensate well. The rapid onset of very severe anemia can lead to the manifestation of cardiovascular decompensation of insufficient oxygen supply. Symptoms and signs related to hemolysis may appear, such as jaundice, tea-colored urine, and soy-colored urine. Other nonspecific symptoms include abdominal pain or fever. The most common manifestations in children with CAD may be post-cold red blood cell agglutination-related symptoms such as:
  • Cyanosis of the extremities (i.e., the skin on the most distal extremities of the extremities such as fingertips, toes, and the skin of the ears and nose turns dark purple to grayish white), warm symptoms disappeared.
  • Wine-colored, cola-colored, and black hemoglobinuria often indicates intravascular hemolysis due to cold antibody-type AIHA, such as CAD or PCH.
AIHA's laboratory tests (1) to determine whether hemolytic anemia: complete blood count, reticulocyte count, peripheral blood smear, direct antiglobulin test (DAT, direct Coombs test), urinalysis, blood urea nitrogen and creatinine, indirect bilirubin, lactate dehydrogenase (LDH), aspartate aminotransferase (AST). The details are as follows:
  • DAT: It is a diagnostic test for AIHA, which can identify the type of antibody and/or complement on the surface of red blood cells and score in a semi-quantitative form. The positive intensity of DAT results is generally related to the severity of hemolysis; conventional DAT tests detect IgG, IgM and/or C3d antibodies. Fewer than 5% of children, despite clinical evidence of warm AIHA, were negative because the amount of IgG on the surface of red blood cells was below the threshold detectable by standard DAT.
  • Indirect antiglobulin test (IAT): The purpose is to check for the presence of free antibodies in serum. It is commonly used to detect maternal antibodies in patients with suspected hemolytic disease of the newborn and blood group antibodies due to transfusion of incompatible red blood cells.
(2) Determine the etiology of hemolysis:
  • Autoimmune disease detection (antinuclear antibodies, etc.), etiological detection (virus, Mycoplasma pneumoniae, etc.), tumor-related detection (bone marrow, etc.) puncture, etc.), congenital hemolytic anemia related tests (hemoglobin electrophoresis, G-6-PD activity, red blood cell osmotic fragility test, etc.), peripheral blood cell CD55/59 detection, etc.
  • Cold agglutinin titers should also be measured if there is hemoglobinuria, Mycoplasma pneumoniae infection, cyanosis of lower extremities exposed to cold, etc. When analysing the etiology, it is also necessary to carefully review the child's previous medication.
The flowchart of the differential diagnosis of AIHA is as follows: Figure 1 The flowchart of the differential diagnosis of AIHA (can be enlarged) AIHA treatment flowchart Symptoms and signs and characteristics of autoantibodies. Children with AIHA can be treated on an outpatient basis if the anemia is not severe and there are no signs of HF; however, acute onset may require hospitalization for diagnostic evaluation, close monitoring of the patient, and rescue of critically ill children. Secondary AIHA needs to be quickly removed from contact factors (such as drugs) and control the primary disease (such as infection, tumor, etc.), and the treatment will have a good effect. The treatment process is shown in Figure 2 below. Figure 2 AIHA treatment flow chart (can be zoomed in) About blood transfusion (1) Try to avoid or reduce blood transfusion: AIHA has increased the difficulty of cross-matching blood due to the existence of autoantibodies and increased the risk of hemolytic transfusion reaction caused by alloantibodies. Blood transfusions should be avoided or minimized. (2) Timing of blood transfusion: It should be determined according to the degree of anemia, the presence or absence of obvious symptoms, and the speed of occurrence. Blood should also be given if the anemia is life-threatening. (3) Indications for blood transfusion:
  • For children with acute hemolytic anemia, if alloantibodies can be excluded when severe symptoms appear, red blood cells need to be transfused immediately;
    < li> For patients with chronic anemia, if HGB is above 70g/L, no blood transfusion is required; when HGB is between 50g/L and 70g/L, blood transfusion can be appropriate if there are intolerable symptoms; blood transfusion should be considered when HGB is below 50g/L .
(4) Precautions for blood transfusion:
  • The use of washed red blood cells is not emphasized during rescue. Infusion, slow infusion is required, and blood transfusion reactions are closely observed;
  • The survival time of donor red blood cells infused in AIHA patients is similar to that of the patient's own red blood cells. However, even if the transfused red blood cells can only exist in the circulation for a short time, it can still help improve the symptoms and signs of anemia;
  • Adding glucocorticoids before transfusion can reduce or alleviate the occurrence of transfusion reactions.
References: [1] Guidelines for the diagnosis and treatment of autoimmune hemolytic anemia in children (2021 edition). [2] Crab and crab. What should I do if acute hemolytic anemia is found clinically? Seeing blood at a diagnosis. Medical blood channel, 2021-1-7. This article was first published: Pediatrics channel in the medical community 👇1. Scan the QR code below 2. Click "Download Now" to download the Doctor Station App, and subscribe anytime, anywhere~ Copyright Statement This article is original and welcome to forward it to Moments - End - The medical community strives for the accuracy and reliability of its published content when it is approved. However, it does not make any commitments and guarantees for the timeliness of the published content and the accuracy and completeness of the cited data (if any), nor does it assume any inaccuracies or inaccuracies due to the outdated content and the cited data. any liability arising from circumstances such as completeness. Relevant parties are requested to check separately when adopting or using it as a basis for decision-making.
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