Autoimmune hemolytic anemia natural history, complications and prognosis
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Assosciate Editor(s)-In-Chief: Prashanth Saddala M.B.B.S; Shyam Patel [2], Irfan Dotani [3]
Overview
The natural history of autoimmune hemolytic anemia begins with the hemolytic event. A diagnostic workup is typically initiated soon after the hemolytic event, and the hemolysis subsides after the start of corticosteroids. Most patients will generally achieve remission with no long-term complications. For patients who develop complications, these complications include infection, thrombosis, iron overload, and end-organ damage from impaired oxygen delivery. The prognosis of autoimmune hemolytic anemia depends on the severity of the immune activation. The prognosis is overall favorable for most patients.
Natural History, Complications, and Prognosis
Natural History
- The natural history of autoimmune hemolytic anemia begins with the hemolytic event.
- Patients usually present for evaluation after they experience symptoms of fatigue, shortness of breath, or decreased exercise tolerance, as the anemia becomes worse.
- At hemoglobin levels of less than 8 g/dl, symptoms will usually be apparent.
- After presenting with these symptoms and a diagnosis of autoimmune hemolytic anemia is made, patients are started on corticosteroids.
- A response will usually occur within 1-2 weeks, after which symptoms will likely abate.
- Hemoglobin will return towards normal range, and this can be maintained via a steroid taper over the next few weeks to months.
- The natural history of autoimmune hemolytic anemia is self-limited in children if treated with corticosteroids.
- Most children respond very well to steroids and can lead normal lives without frequent relapses or recurrences.[1]
- After recovery from the initial hemolytic episodes, it is unlikely that children will relapse.
- In older children, autoimmune hemolytic anemia can be chronic.[1]
Complications
- Infection:[2]
- This is a serious concern in patients on long-term immunosuppressant therapy, especially in very young children (less than two years).
- Infections occur due to impaired cell-mediated and humoral immunity.
- Different immunosuppressive agents have different infectious complication profiles. For example, patients on rituximab can experience the rare but highly lethal infection with JC virus, which causes progressive multifocal leukoencephalopathy. Severe infections can result in death.
- Thrombosis:[1]
- Patients with autoimmune hemolytic anemia are at higher risk for thrombosis.
- Thrombosis is more likely to occur in the active phase of hemolysis, such as during a severe hemolytic episode.
- Anti-phospholipid antibodies are associated with the occurrence of thrombosis, as these antibodies bind to platelet membranes and induce thrombosis.
- Patients with autoimmune hemolytic anemia who have a known history of thrombosis or are at high risk for thrombosis from other etiologies should begin anticoagulation.
- Iron overload:
- Autoimmune hemolytic anemia is frequently complicated by iron overload due to frequent red blood cell transfusions.
- In patients for whom steroids do not work, red blood cell transfusions can be an important temporizing measure to maintain the hemoglobin concentration with a safe range. For example, a typical hemoglobin threshold of 7g/dl is used when considering transfusion requirements.
- However, a major adverse effect of frequent transfusions is iron overload, as iron can deposit in a variety of organs and result in impaired organ function. For these reasons, it is best to address the underlying cause (immune activation) of autoimmune hemolytic anemia, rather than provide transfusional support in the long-term.
- Hepatic iron overload:
- Iron deposition in the liver can be detected via T2 STAR magnetic resonance imaging (MRI) or by liver biopsy showing Prussian blue staining of hepatocytes.
- Iron deposition in the liver can result in symptoms of abdominal distension, bleeding, jaundice, edema, and portal hypertension.
- Treatment involves iron chelators such as deferoxamine, deferasirox, or deferiprone.
- Cardiac iron overload:
- Iron deposition in the heart can be detected via echocardiogram showing diastolic dysfunction, electrocardiogram (EKG) showing low voltage complexes, T2 STAR magnetic resonance imaging MRI, or cardiac biopsy showing Prussian blue staining of cardiomyocytes.
- Iron deposition in the heart can result in symptoms of fatigue, shortness of breath, chest pain, edema, orthopnea, and paroxysmal nocturnal dyspnea.
- Treatment involves iron chelators such as deferoxamine, deferasirox, or deferiprone.
- Hepatic iron overload:
- End-organ damage from impaired oxygen delivery: The effects of severe anemia affect a variety of organs and tissues that rely heavily on oxygen for energy metabolism. If hemoglobin decreases significantly, typically to values lower than 7g/dl, patients can experience impaired oxygen delivery and end-organ hypoxia. If hemoglobin decreases significantly, typically to values lower than 7g/dl, patients can experience impaired oxygen delivery and end-organ hypoxia.
- Hypoxic brain injury:
- This is a rare but important complication of severe anemia.
- Low oxygen delivery to the brain as a result of autoimmune hemolytic anemia can result in ischemic injury to neurons and supporting tissue.
- This is functionally similar to cerebrovascular accident, or stroke, which is due to atherosclerotic or embolic blockage of the cerebral circulation.
- Patients can experience severe symptoms such as numbness, weakness, paralysis, and dysarthria, or slurred speech.
- Patients can have a significant neurological impairment (including deficits in motor, sensory, cortical, and cerebellar function).
- Overall, the likelihood of hypoxic brain injury due to autoimmune hemolytic anemia is very low.
- Myocardial injury:
- Autoimmune hemolytic anemia can result in impaired oxygen delivery to the cardiac tissue.
- Myocardial infarction can result from poor oxygen content in the coronary circulation, which is functionally similar to having ischemia due to blockage by an atherosclerotic plaque.
- Patients can experience severe symptoms such as shortness of breath, fatigue, and decreased exercise tolerance.
- Anemia is associated with poor outcomes.[3]
- Patients can have long-term complications such as congestive heart failure.
- High-output cardiac failure:
- Hemolytic anemia can also be associated with high-output cardiac failure, in which the ejection fraction and cardiac output are higher than normal.
- This is a manifestation of impaired oxygen delivery at the tissue level, for which the body compensated by increasing the circulatory output in an attempt to deliver more oxygen to tissues.
- High-output cardiac failure can lead to congestive heart failure.
- Hypoxic brain injury:
Prognosis
- The prognosis of autoimmune hemolytic anemia is variable and depends on the severity of the immune activation.[1]
- In the early 2000s, studies reported a 10-year survival of 73%.[1]
- In the current era, the survival is likely better.[1]
- The mortality rate is 10-30%.[1]
- Patients with concurrent immune thrombocytopenia purpura have a higher mortality rate. This condition is known as Evan's syndrome.[1]
Secondary autoimmune hemolytic anemia
The prognosis for secondary autoimmune hemolytic anemia depends on the underlying cause.
- Chronic lymphocytic leukemia :
- In patients with chronic lymphocytic leukemia (CLL), for example, the hemolysis can continue for months to years if the underlying disease is high-risk. On the contrary, patients with CLL with favorable risk features may have limited hemolysis and excellent prognosis.
- Rheumatologic conditions:
- In patients with systemic lupus erythematosus (SLE) or other rheumatologic conditions, the severity of the hemolytic anemia corresponds with the degree of aberrant immune activation. The severity of the hemolysis parallels other autoimmune components of these diseases. The prognosis in patients with severe SLE may be dismal.
Other hemolytic anemias
The prognosis of other types of hemolytic anemias is variable and depends on the subtype of hemolytic anemia.
- Paroxysmal cold hemoglobinuria: In contrast to autoimmune hemolytic anemia, patients with paroxysmal cold hemoglobinuria have an excellent prognosis in the absence of cold weather.[1] Patients can survive for years.
- Drug-induced hemolytic anemia: The prognosis for drug-related hemolysis is excellent with removal of the offending agent. Hemolysis usually resolves once the culprit drug is discontinued. After a period of weeks, the drug-dependent antibody will be eliminated, and the direct antiglobulin test will be negative. However, if the drug is not removed, hemolysis will likely continue and can contribute to severe ongoing anemia.[1]
- Post-infectious cold hemoglobinuria: The prognosis of post-infectious cold hemoglobinuria is excellent upon clearance of the infectious agent, which is usually a virus. Hemolysis will cease after a period of weeks. The Donath-Landsteiner antibody, which is a biphasic hemolysin, will usually abate once the infection clears.[1]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Packman CH (2015). "The Clinical Pictures of Autoimmune Hemolytic Anemia". Transfus Med Hemother. 42 (5): 317–24. doi:10.1159/000440656. PMC 4678314. PMID 26696800.
- ↑ Zecca M, Nobili B, Ramenghi U; et al. (2003). "Rituximab for the treatment of refractory autoimmune hemolytic anemia in children". Blood. 101 (10): 3857–61. doi:10.1182/blood-2002-11-3547. PMID 12531800. Unknown parameter
|month=ignored (help) - ↑ Park S, Jung CW, Kim K, Kim SJ, Kim WS, Jang JH (2015). "Iron deficient erythropoiesis might play key role in development of anemia in cancer patients". Oncotarget. 6 (40): 42803–12. doi:10.18632/oncotarget.5658. PMC 4767472. PMID 26517509.