Aplastic crisis refers to a condition of drastic deterioration in the formation of red blood cells (RBCs) in the setting of hemolytic anemia. The cause of this crisis is usually the coincidence of chronic hemolytic anemia with ringworm infection. Only blood transfusion can overcome this critical condition.
What is an aplastic crisis?
Aplastic crisis is a rare complication of certain viral infections. In particular, the virus responsible for ringworm triggers an aplastic crisis under certain conditions. The virus in question is parvovirus B19. The prerequisite for this crisis, however, is a chronic hemolytic anemia in addition to the viral infection. In the context of hemolytic anemia, rapid breakdown of red blood cells (hemolysis) occurs due to various causes. The viruses ultimately responsible for triggering the aplastic crisis additionally prevent the formation of new blood cells from the stem cells of the bone marrow. As a result, the body is threatened with short-term depletion of all erythrocytes without their new formation. The crisis-like reduction of erythrocytes is life-threatening because the oxygen supply of the organism is highly endangered as a result. The prognosis depends on the severity of the erythrocyte deficiency. The word “aplastic” means lacking or absent. From this derives the term “aplastic crisis,” which is generally characterized by the sudden reduction of red blood cells in the presence of preexisting chronic hemolytic anemia.
Causes
The cause of aplastic crisis is always infection with viruses that directly inhibit red cell production. In most cases, this is parvovirus B19. Another prerequisite, as mentioned above, is the presence of chronic hemolytic anemia. Parvovirus B19 triggers the normally harmless ringworm infection. Since infection with parvovirus B19 results in lifelong immunity, children are preferentially affected because the infection rate is high in children. As adults, they are then immune. However, adults who did not contract ringworm as children can still become infected with this virus. The virus itself infects the precursor cells of the erythrocytes and interferes with the transformation of these stem cells into mature red blood cells. Thus, infection with parvovirus B19 is associated with temporary anemia, because during the time when no erythrocytes are formed, mature erythrocytes always die. This is a normal process that takes place all the time. The virus becomes a danger only in people who already suffer from chronic hemolytic anemia. In hemolytic anemia, increased degradation of red blood cells takes place from the outset. If both processes occur together, a dangerous deficiency of red blood cells can result, which is often fatal. Infection with ringworm virus alone does not usually cause severe anemia. Here, before the normal breakdown of erythrocytes leads to a threatening red cell deficiency, the infection is already in remission and red blood cell production restarts. Chronic hemolytic anemia, in turn, can have many causes. Often it is a genetic blood disorder such as sickle cell anemia, spherical cell anemia, thalassemia, paroxysmal nocturnal hemoglobinuria, or glucose-6-phosphate dehydrogenase deficiency (favism). However, autoimmune diseases, in which the immune system targets the body’s own red cells, can also cause hemolytic anemia. Other causes may include drug intoxication or other rare diseases. Thus, aplastic crisis is both a possible complication of parvovirus B19 infection and of chronic hemolytic anemia, which occurs only when both conditions are present simultaneously.
Symptoms, complaints, and signs
In general, ringworm infection is either asymptomatic or presents with a flu-like appearance without a rash or only a rash without other adverse health effects. In individuals with chronic hemolytic anemia, the infection progresses without a rash. Instead, the symptoms of an aplastic crisis quickly appear. The patient quickly becomes pale and increasingly tired. Other symptoms include fever, headache, abdominal pain or vomiting.Without treatment, severe oxygen deprivation occurs with the risk of cardiovascular collapse.
Diagnosis and course
The diagnosis of aplastic crisis is initially made on the basis of the presenting symptoms in the setting of ringworm infection. In most cases, hemolytic anemia is also already known. If an infection with parvovirus B19 also occurs, the diagnosis of aplastic crisis can be made as soon as the typical symptoms appear. Laboratory tests reveal a sharp drop in hemoglobin concentration to 3 to 4 g/dL within a few days. Reticulocytes are almost completely absent. These are young immature erythrocytes that should have just formed from their precursor cells. This absence indicates that the formation of erythrocytes is just not taking place. More rarely, the concentration of platelets (thrombocytes) and neutrophil granulocytes (white blood cells) is decreased.
Complications
Aplastic crisis requires chronic hemolytic anemia and results from rapid deterioration in red blood cell production. The symptom is associated with viral infection and represents an extreme situation for the affected person. Aplastic crisis primarily affects children of all ages. However, the symptom can also break out in adults who do not have immunity, especially against ringworm. The crisis is triggered by viruses that directly attack the stem cells of the bone marrow and from there stop all blood cell formation. The life-threatening condition endangers the oxygen supply of the organism. The complication consequences are fatal and can lead to death if medical help is not intervened in time. Usually, the symptom is characterized by pallor, fatigue, abdominal pain, vomiting and headache accompanied by fever. In children affected by CDA, the onset of an aplastic crisis is particularly dangerous. The spontaneous drop in highly concentrated red blood pigment sets off an immediate anemia. Cardiovascular failure ensues. Parents who fail to recognize or misinterpret the signs of the disease put the child’s life in danger. It belongs immediately to the emergency ward, where a blood transfusion is initiated. The transfusion has no complications and helps the weakened body fight the virus. CDA patients should always avoid contact with persons with viral illness.
When should you see a doctor?
A physician should be consulted immediately if an aplastic crisis is suspected. If the typical signs of illness (flu-like symptoms, abdominal pain, fever) are noticed, a visit to the doctor is recommended for further clarification. A medical diagnosis of the underlying disease is advisable for reasons of infection risk alone. Therefore, if there are signs of an aplastic crisis, the family doctor or pediatrician should be consulted in any case. A concrete suspicion, for example if the symptoms are directly related to a viral infection, medication abuse or a prolonged medical history, requires immediate medical clarification. If severe symptoms such as pallor, fatigue, severe nausea or vomiting are evident, emergency medical services must be called immediately. Infants and young children should be taken immediately to the nearest emergency department if they show signs of an aplastic crisis. This is especially recommended if there is a history of immune or cardiovascular disease. In the event of circulatory collapse or cardiac failure, first aid measures must also be taken. When the ambulance arrives, it must be informed of the possible cause.
Treatment and therapy
Aplastic crisis represents a severe emergency, which requires immediate treatment to avert a life-threatening oxygen deficit. In this situation, a blood transfusion must be performed urgently to prevent cardiovascular failure. The blood transfusion can be used to bridge the time until the virus is fully controlled.
Outlook and prognosis
Aplastic crisis represents an emergency situation. Without immediate medical attention, the patient faces rapid demise. The body has no way on its own to help or heal itself in the situation. The longer intensive medical care is not provided, the higher the risk of death for the affected person. With rapid and professional treatment, the prognosis prospects change considerably.In an adult person without other serious illnesses and with a basically stable immune system, a complete recovery is given within a few days or weeks. However, since the crisis is usually triggered by a medical incident or illness, the underlying disease is largely responsible for any chance of recovery. If the patient suffers from aplastic anamnesis, there is a high risk of death. Even if the aplastic crisis can be overcome, complications may occur further down the line, resulting in loss of life. With a single episode of red blood cell deficiency, the prognosis improves immensely. Aplastic crisis is often triggered by a viral infection. Once the triggering virus can be diagnosed and treated, the patient is on the road to health improvement. Normally, recovery is achieved within the next few weeks or months.
Prevention
Individuals with chronic hemolytic anemia are strongly advised to protect themselves from infection with parvovirus B19 to avoid anaplastic crisis. For example, children at risk should urgently avoid contact with ill children by staying home if cases of ringworm occur at school or kindergarten. However, if contact has nevertheless occurred, it is necessary to consult a physician immediately.
Follow-up
Children who suffer an aplastic crisis due to infection with parvovirus B19 are subsequently immune for life. In them, therefore, follow-up cannot aim to prevent recurrence. This does not mean, however, that no follow-up examinations are necessary. Since the immune system is weakened even several weeks after an illness, a series of blood tests follows after discharge from the hospital. Sometimes aplastic crisis affects adults. They have not developed immunity and therefore can become infected again and again. A blood transfusion is indicated for them immediately after the onset of typical symptoms. Patients bear a high degree of personal responsibility in everyday life to prevent infection. Other sick persons should be avoided. If viral diseases are rampant, affected persons should rather stay at home. After an aplastic crisis, rest and a healthy lifestyle prevent complications. Basically, the extent of aftercare depends on the underlying disease. After all, an aplastic crisis represents the aggravation of an unfavorable initial situation. To prevent life-threatening consequences, the emergency physician should be contacted immediately in the event of an acute onset. In some cases, there is a high risk of death.
What you can do yourself
Aplastic crisis is a life-threatening condition for affected patients, and self-help measures take a back seat. The disease requires emergency medical treatment and, in the absence of timely therapy, sometimes leads to the death of the predominantly child patients. Thus, it is usually the parents who make a significant contribution to the prospects of recovery from the disease by providing their child with appropriate medical care as soon as possible. The patients are usually in a hospital during the therapy of the acute symptoms, where the parents are present at best. In this way, the child receives emotional support and treatment steps that need to be discussed with the parents can be carried out more quickly. In the case of the present illness, a blood transfusion is usually necessary, so that the patients are temporarily in intensive medical care. The patients follow the instructions of the hospital staff and avoid contact with other people in order to reduce the risk of infection with other diseases in their own interest. After the disease has been overcome, further medical follow-up checks are necessary in order to quickly detect any consequential damage. A few weeks after recovery, the patient’s immune system is still weakened, so they should refrain from extensive sports and other activities. A healthy diet supports physical regeneration.
