Autoimmune hemolytic anemia: Difference between revisions

Revision as of 18:34, 7 September 2016

Background

Autoimmune hemolytic anemia (AIHA) = generation of auto-antibodies towards red blood cell membrane antigens, leady to hemolysis.
Can be primary (idopathic) or due to another disease process (e.g. malignancy, autoimmune disease, infection)

"Warm" Autoimmune Hemolytic Anemia

Autoantibodies agglutinate to RBCs at higher temperatures

IgG mediated, usually pan-reactive to patient's and transfused RBCs
Extravascular (i.e. in spleen) hemolysis--> unconjugated > conjugated hyperbilirubinemia
Haptoglobin low, LDH may be normal
Causes:
- Lymphoma, especially Non-Hodgkin's lymphoma
- Leukemia, particularly chronic lymphocytic leukemia
- Collagen vascular diseases (E.g. Systemic Lupus Erythematosus, Rheumatoid arthritis, Giant cell arteritis
- Viral-induced or HIV-associated
- Medications: methyldopa, quinidine, penicillin

"Cold" Autoimmune Hemolytic Anemia

Autoantibodies agglutinate at lower temperatures

IgM mediated
Intravascular hemolysis--> high LDH, low haptoglobin, hemoglobinuria
Causes:
- Infection, most commonly Mycoplasma pneumoniae and mononucleosis, also varicella, listeria, influenza
- Multiple myeloma and other plasmacytomas
- Idiopathic

Clinical Features

Signs and symptoms of anemia (fatigue, pallor, palpitations, etc.)
Jaundice and scleral icterus
Signs/symptoms of underlying disease process
Cold-type:
- Acrocyanosis, Raynaud's, vascular occlusion with peripehral tissue ischemia

Diagnosis

CBC, LFTs, LDH, haptoglobin
Direct Coombs test - blood sample is removed of plasma and incubated with anti-human immunoglobulin (aka "Coombs reagent"). This detects if autoantibodies are attached to RBCs or compliment. If the RBCs are coated with IgG (positive direct Coombs test), this suggests the diagnosis of "warm AIHA. If the RBCs are coated with only compliment, this suggests the diagnosis of "cold" AIHA

Treatment

Warm AIHA
- Oral prednisone 1-1.5mg/kg/day for 1-3 weeks with taper after hemoglobin stable
  - may need several months of low dose prednisone to remain in remission
- Splenectomy and/or cytotoxic drugs for for steroid-refractory disease
- Plasmapharesis as temporizing measure for severe disease
Transfuse only if truly life-threatening anemia, least incompatible units possible

Cold AIHA
- No treatment for mild disease
- Immunosuppressive or cytotoxic medications can be considered
- Plasmapharesis for severe disease

@@ Line 2: / Line 2: @@
 *Autoimmune hemolytic anemia (AIHA) = generation of auto-antibodies towards red blood cell membrane antigens, leady to hemolysis.
 *Can be primary (idopathic) or due to another disease process (e.g. malignancy, autoimmune disease, infection)
-=="Cold" Autoimmune Hemolytic Anemia==
-Cold AIHA refers to hemolytic disease caused by cold reacting autoantibodies, i.e. autoantibodies that agglutinate to RBCs at lower temperatures (usually 0°C-5°C). This is the less common than "warm" AIHA, and is typically mediated by IgM autoantibodies. When IgM autoantibodies attach to the RBCs, they cause an [[intravascular hemolysis]], meaning that hemolysis and release of all intracellular contents occurs within the blood vessels. This results in elevated serum LDH, low haptoglobin, and presence of hemoglobinuria (due to the release of unprocessed hemoglobin into the blood stream. Causes "cold" AIHA" include:<br />
-# Infection - most commonly [[''Mycoplasma'' ''pneumoniae'']] infection and infectious [[mononucleosis]]<br />
-# Plasmacytomas - specifically [[Multiple Myeloma]]<br />
-# Idiopathic
 =="Warm" Autoimmune Hemolytic Anemia==
@@ Line 20: / Line 14: @@
 **Viral-induced or [[HIV]]-associated
 **Medications: methyldopa, quinidine, [[penicillin]]
+=="Cold" Autoimmune Hemolytic Anemia==
+''Autoantibodies agglutinate at lower temperatures''
+*IgM mediated
+*Intravascular hemolysis--> high LDH, low haptoglobin, hemoglobinuria
+*Causes:
+**Infection, most commonly [[Mycoplasma pneumoniae]] and [[mononucleosis]], also [[varicella]], [[listeria]], [[influenza]]
+**[[Multiple myeloma]] and other plasmacytomas
+**Idiopathic
 ==Clinical Features==
--Signs and symptoms of anemia (fatigue, pallor, palpitations, etc.)<br />
+*Signs and symptoms of [[anemia]] (fatigue, pallor, palpitations, etc.)
--Jaundice and scleral icteris from hyperbilirubinemia<br />
+*[[Jaundice]] and scleral icterus
--Features related to the patient's underlying disease process that is causing their AIHA
+*Signs/symptoms of underlying disease process
+*Cold-type:
+**Acrocyanosis, Raynaud's, vascular occlusion with peripehral tissue ischemia
 ==Diagnosis==
-Direct Coombs test - blood sample is removed of plasma and incubated with anti-human immunoglobulin (aka "Coombs reagent"). This detects if autoantibodies are attached to RBCs or compliment. If the RBCs are coated with IgG (positive direct Coombs test), this suggests the diagnosis of "warm AIHA. If the RBCs are coated with only compliment, this suggests the diagnosis of "cold" AIHA
+*CBC, LFTs, LDH, haptoglobin
+*Direct Coombs test - blood sample is removed of plasma and incubated with anti-human immunoglobulin (aka "Coombs reagent"). This detects if autoantibodies are attached to RBCs or compliment. If the RBCs are coated with IgG (positive direct Coombs test), this suggests the diagnosis of "warm AIHA. If the RBCs are coated with only compliment, this suggests the diagnosis of "cold" AIHA
 ==Treatment==
-Warm AIHA<br />
+*Warm AIHA
--Glucocorticoids are first-line<br />
+**Oral [[prednisone]] 1-1.5mg/kg/day for 1-3 weeks with taper after hemoglobin stable
--Splenectomy for patient's with refractory disease to glucocorticoid therapy<br />
+***may need several months of low dose prednisone to remain in remission
+**Splenectomy and/or cytotoxic drugs for for steroid-refractory disease
+**Plasmapharesis as temporizing measure for severe disease
+*Transfuse only if truly life-threatening anemia, least incompatible units possible
-Cold AIHA<br />
+*Cold AIHA
--Typically no treatment is necessary as disease is self-limited and recommendations to avoid cold temperatures is typically sufficient<br />
+**No treatment for mild disease
--RBC transfusion for significant and symptomatic disease<br />
+**Immunosuppressive or cytotoxic medications can be considered
--Glucocorticoids are '''not''' indicated
+**Plasmapharesis for severe disease
 ==Further Reading==
-[[Paroxysmal nocturnal hemoglobinuria]] (PNH)<br />
+[[Paroxysmal nocturnal hemoglobinuria]] (PNH)
-[[Systemic lupus erythematosus]]<br />
+[[Systemic lupus erythematosus]]
-[[Rheumatoid arthritis]]<br />
+[[Rheumatoid arthritis]]
 [[Scleroderma]]