Autoimmune hemolytic anemia overview: Difference between revisions

Jump to navigation Jump to search
No edit summary
Line 53: Line 53:


===Imaging Findings===
===Imaging Findings===
 
There is no primary role for chest X-ray in diagnosis or evaluation of autoimmune hemolytic anemia, but chest X-ray can be useful to help diagnose other conditions associated with autoimmune hemolytic anemia, such as volume overload states from frequent transfusions.
===Other Diagnostic Studies===
===Other Diagnostic Studies===



Revision as of 18:39, 13 April 2018

Autoimmune hemolytic anemia Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Autoimmune hemolytic anemia from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X-ray

Echocardiography and Ultrasound

CT

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Autoimmune hemolytic anemia overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Autoimmune hemolytic anemia overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Autoimmune hemolytic anemia overview

CDC on Autoimmune hemolytic anemia overview

Autoimmune hemolytic anemia overview in the news

Blogs on Autoimmune hemolytic anemia overview

Directions to Hospitals Treating Autoimmune hemolytic anemia

Risk calculators and risk factors for Autoimmune hemolytic anemia overview

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]

Overview

Autoimmune hemolytic anemia is a type of hemolytic anemia where the body's immune system attacks its own red blood cells, leading to their destruction (hemolysis). Antibodies and associated complement system components become fixed onto the red blood cell surface. These antibodies can be detected with the Coombs test or direct Coombs test. Autoimmune hemolytic anemia can also be induced by infections such as Mycoplasma pneumoniae, drugs such as methyldopa and fludarabine, or malignancies such as chronic lymphocytic leukemia or non-Hodgkin lymphoma.

Historical Perspective

The history of studies on autoimmune hemolytic anemia begins in the early 20th century with the description of clinical syndromes involving low hemoglobin in the setting of a circulating antibody. Various groups reported on the production of antibodies that could bind to red blood cells at either warm or cold temperatures. Over the years, diagnostic tests were developed and optimized to determine the exact type of antibody involved in hemolysis. Treatment modalities were developed, beginning with corticosteroids. Other immunosuppressive medications, such as rituximab, were soon found to be effective in patients with hemolytic anemia.

Classification

Autoimmune hemolytic anemia is classified into 3 broad categories. These include warm-antibody type, cold-antibody type, and mixed-antibody type. Each category is characterized by a different autoantibody (IgG or IgM) and different optimal binding temperatures (37 degrees Celsius or 4-18 degrees Celsius). Each condition is associated with different triggers, including infections, medications, and malignancies. The warm-antibody type is the most common, and the mixed-antibody type is rare and not well characterized.

Pathophysiology

The pathophysiology of autoimmune hemolytic anemia is different for warm-antibody type and cold-antibody type anemia. The pathophysiology of warm-antibody type autoimmune hemolytic anemia involves the coating of red blood cells with IgG, followed by extravascular hemolysis by splenic macrophages. The pathophysiology of cold-antibody type autoimmune hemolytic anemia involves the coating of red blood cells with IgM, followed by intravascular hemolysis. The complement system has a significant role in autoimmune hemolytic anemia and involves the binding of classical complement proteins on the red blood cell surface, followed by cell lysis by the membrane attack complex. In summary, a variety of cell-mediated immunologic mechanisms underlie the pathophysiology of autoimmune hemolytic anemia.

Causes

Autoimmune hemolytic anemia is caused by primary and secondary conditions. Secondary conditions that cause autoimmune hemolytic anemia include malignancies, autoimmunity, and medications. Malignancies that cause autoimmune hemolytic anemia include chronic lymphocytic leukemia and non-Hodgkin lymphoma. Autoimmune conditions that cause autoimmune hemolytic anemia include systemic lupus erythematosus, primary biliary cirrhosis, and others. Medications that cause autoimmune hemolytic anemia include methyldopa and fludarabine.

Differentiating Autoimmune Hemolytic Anemia from Other Diseases

A variety of conditions comprise the differential diagnosis of autoimmune hemolytic anemia. These include microangiopathic hemolytic anemia, paroxysmal cold hemoglobinuria, paroxysmal nocturnal hemoglobinuria, hereditary spherocytosis, pernicious anemia, and chronic lymphocytic leukemia. The diagnosis of autoimmune hemolytic anemia can sometimes be made by first ruling out these other causes. It is important to distinguish amongst these conditions since the prognosis and treatment of each condition is different.

Epidemiology and Demographics

Overall, the incidence and prevalence of autoimmune hemolytic anemia is low. This condition affects a very small proportion of the population. Autoimmune hemolytic anemia affects men and women equally. There is no racial predilection for autoimmune hemolytic anemia.

Risk Factors

The risk factors for autoimmune hemolytic anemia include systemic lupus erythematosus and immunotherapeutic medications. Systemic lupus erythematosus is thought to be a strong risk factor for autoimmune hemolytic anemia. However, immunotherapeutic medications may become a more prevalent risk factor in the coming years as these agents are becoming used increasingly for a variety of cancers. These medications include anti-PD-1 antibodies and anti-CTLA-4 antibodies.

Screening

Screening for autoimmune hemolytic anemia is not currently done routinely.

Natural History, Complications, and Prognosis

Natural History

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.

Complications

For patients who develop complications, these complications include infection, thrombosis, iron overload, and end-organ damage from impaired oxygen delivery.

Prognosis

The prognosis of autoimmune hemolytic anemia depends on the severity of the immune activation. The prognosis is overall favorable for most patients.

Diagnosis

History and Symptoms

Patients with autoimmune hemolytic anemia have gradual onset of fatigue and can develop shortness of breath and decreased exercise tolerance. The symptoms of autoimmune hemolytic anemia depend on the severity of disease.

Physical Examination

Physical exam findings in patients with autoimmune hemolytic anemia vary depending on the severity of the disease. Exam findings include pallor, clubbing, jaundice, scleral icterus, splenomegaly, and abdominal tenderness.

Laboratory Findings

Laboratory findings in patients with autoimmune hemolytic anemia include anemia, positive Coombs' test, positive indirect anti-globulin test, hemoglobinuria, low haptoglobin, increased spherocytes, and elevated lactate dehydrogenase (LDH). Not all patients will have all of these findings. The severity of hemolysis will determine the degree of laboratory abnormalities.

Imaging Findings

There is no primary role for chest X-ray in diagnosis or evaluation of autoimmune hemolytic anemia, but chest X-ray can be useful to help diagnose other conditions associated with autoimmune hemolytic anemia, such as volume overload states from frequent transfusions.

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Prevention

References

Template:Hematology


Template:WikiDoc Sources