Intravascular hemolysis is an important part of many anemias depending on its severity, hemolysis may contribute to vascular complications pulmonary hypertension, stroke, blood clots, leg ulcers, priapism screening strategies and treatments have been developed in scd. Causes include mechanical trauma, complement fixation, and other toxic damage to the rbc. Sudden onset of severe anemia in a patient with cystic fibrosis 5 sickle cell disease usually causes extravascular hemolysis, rather than intravascular hemolysis, as the abnormal sickleshaped rbcs are hemolyzed in the. Black belt convert web pages to pdf firefox addons download helper training support for bujinkan hemolysis intra y extravascular pdf download taijutsu. Extravascular hemolysis definition of extravascular. A 67yearold woman with rheumatic aortic stenosis for 20 years was admitted to our hospital. Yes, the bilirubin passing through the canaliculi is predominantly conjugated, and only trace amounts of unconjugated. Attachment of igg or igm causes fixation of complement to c3b on red cell membranes. Hemolysis is characterized by a compensatory reticulocytosis. Autoimmune hemolytic anemia and hereditary spherocytosis are examples of extravascular hemolysis because the red blood cells are destroyed in the spleen and other reticuloendothelial tissues. In a recent large retrospective study of 308 cases of primary aiha, hemoglobin values at. There are numerous causes of hemolytic anemia, including inherited and acquired conditions, acute and chronic processes, and mild to potentially lifethreatening severity.
Objectives lab indication of hemolysis intravascular vs extravascular hemolysis dd of hemolytic anemia diagnose hemo. Acute intravascular hemolysis is due to destruction of erythrocytes by a sudden flux of copper ions from the necrosing hepatocytes. Hemolytic anemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells rbcs, either in the blood vessels intravascular hemolysis or elsewhere in the human body extravascular. Hemolysis is the destruction of red blood cells in the circulation way before their life span is over. Extravascular definition of extravascular by medical. Extravascular hemolysis occurs solely because macrophages are killing more rbcs. Extravascular hemolysis article about extravascular. Macrophages possess receptors for the fc portion of igg and igm as well as for c3b, thus causing red blood cells with attached immunoglobulin or c3b to be phagocytized. Hemolysis is caused by either abnormalities of the rbcs themselves abnormalities in hemoglobin, the rbc membrane or intracellular enzymes, also called corpuscular anemia, or by external causes immunemediated or mechanical damage, which is referred to as extracorpuscular anemia. Hemolytic anemias are a group of conditions characterized by the breakdown of red blood cells. The oxidized free heme metheme binds to hemopexin a. Hemolytic anemia ppt presentation linkedin slideshare. Rother, phd leonard bell, md peter hillmen, mb, phd mark t.
Gladwin, mdh emoglobin is a highly conserved molecule found in speciesrangingfromsinglecell organisms to mammals, but the role of hemoglobin in different organisms varies. Extravascular definition is not occurring or contained in body vessels. Complement c3 inhibition by compstatin cp40 prevents intra and extravascular hemolysis of red blood cells inge baas, 1, laura delvastonunez, 1, 2, peter ligthart, 3 conny brouwer, 3 claudia folman, 3 edimara s. Some microbes form substances called hemolysins that have the specific action of destroying red blood cells. Intravascular vs extravascular hemolysis usmle forum. Indirect bilirubin is a byproduct of hemoglobin catabolism and is increased in intravascular or extravascular hemolysis. Normal red blood cells live for about 3 to 4 months. Hemolytic anemias are typically regenerative and result from lysis of rbcs in either the intra or extravascular space. Immune hemolytic anemia immune hemolytic anemias are mediated by antibod. It oxidizes cell in kidney tubules and can cause acute renal failure. Intravascular hemolysis occurs in hemolytic anemia due to the following. If the damage is severe enough, immediate lysis occurs within the circulation intravascular hemolysis if the damage is less severe, the cell is destroyed within the monocytemacrophage system in the spleen, liver, bone marrow, and lymph nodes extravascular hemolysis iv.
Rbcs are coated with antibodies or have abnormal shape of membrane or abnormal inclusion such as heinz bodies in g6pd and so they are attacked prematurely by the liver and spleen phagocytes. Intravascular versus extravascular hemolysis usmle forums. Most pathologic hemolysis is extravascular and occurs when damaged or abnormal rbcs are cleared from the circulation by the spleen and liver. Hemolysis may be either intravascular or extravascular. Extravascular hemolysis rbcs are coated with antibodies or have abnormal shape of membrane or abnormal inclusion such as heinz bodies in g6pd and so they are attacked prematurely by the liver and spleen phagocytes. Hemolysis is usually described as intravascular hemolysis or extravascular hemolysis. Intravascular hemolysis and the pathophysiology of sickle cell disease article pdf available in journal of clinical investigation 1273. Decreased levels of haptoglobin, a hemoglobinbinding protein that is rapidly cleared from the circulation, is a more specific indicator of rbc breakdown. Hemolytic anemia knowledge for medical students and. Tsuji a1, tanabe m, onishi k, kitamura t, okinaka t, ito m, isaka n, nakano t. Ecf is further divided into interstitial extravascular and bloodplasma intravascular compartments. Hemolysis may occur in vivo or in vitro inside or outside the body one cause of hemolysis is the action of hemolysins, toxins that are produced by certain pathogenic. In intravascular hemolysis rbcs lyse in the circulation releasing hemoglobin into the plasma.
Hemolytic anemia is defined as anemia due to a shortened survival of circulating red blood cells rbcs due to their premature destruction. This is a common cause of extravascular hemolysis in the dog. The unconjugated bilirubin is elevated, as is the lactate dehydrogenase ldh, reflecting rbc breakdown. Hemolysis is the destruction or removal of red blood cells from. The spleen usually contributes to hemolysis by destroying mildly abnormal rbcs or cells coated with warm antibodies. Intravascular hemolysis article about intravascular. So you can see why bilirubin would accumulate, not hgb. When the rbcs are prematurely removed from the circulation and destroyed by the macrophages in the spleen and liver, it is referred to as extravascular hemolysis.
Pdf intravascular hemolysis and the pathophysiology of. We use some laboratory features to identify when intravascular hemolysis is occurring with extravascular hemolysis, as summarized in the table below. The engulfed hemoglobin is converted into iron for recycling and the globine portion becomes billirubin later. As indicated above, extravascular hemolysis is always occurring and is. The clinical sequelae of intravascular hemolysis and. How to measure the fluid volume intra and extra cellular total body water constitutes in men about 60% of body weight, in women 50% is divided into icf and ecf. Hemoglobin is the most direct indicator of clinical severity in hemolytic diseases. Complement c3 inhibition by compstatin cp40 prevents intra. Daven port transfusion medicine division, department of pathology, university of michigan, ann arbor, michigan. Intravascular hemolysis refer to breakdown of red cells in the circulating blood. This most commonly occurs within the spleen, but also can occur in the reticuloendothelial system or mechanically prosthetic valve damage.
In extravascular hemolysis, splenic macrophages phagocytose rbcs, releasing hemoglobin, which is then broken down into heme. It is ubiquitously elevated in all forms of hemolysis, mostly comprised of ldh1 and ldh2 isozymes, and can be useful in trending treatment response. A deficiency of g6pd must be considered in the differential diagnosis of intra and extravascular hemolysis 7. Theres no hemoglobinuria in evh because the rbcs are broken down extravascularly by macrophages and their hemoglobin is never free in the plasma. Pdf a case of extravascular hemolysis with tkactivation. An understanding of this is important for physician assistant exam pance purposes. Hemolysis following wrap aortoplasty for type a aortic.
Intravascular hemolysis results in hemoglobinemia and hemoglobinuria, whereas extravascular hemolysis does not. Extravascular definition of extravascular by merriamwebster. Hemolysis, also spelled haemolysis, also called hematolysis, breakdown or destruction of red blood cells so that the contained oxygen carrying pigment hemoglobin is freed into the surrounding medium. Dark urine and intra vs extravascular hemolysis student. Extravascular hemolysis occurs when red cells are coated with antibody or complement and are taken up macrophages and destroyed outside the circulating blood. Hemolysis can occur due to different causes and leads to the release of hemoglobin into the bloodstream. Intravascular hemolysis results in hemoglobinemia when the amount of hemoglobin released into plasma exceeds the hemoglobinbinding capacity of the plasmabinding protein haptoglobin, a protein normally present in concentrations of about 100 mgdl 1. Overview of hemolytic anemia hematology and oncology. You should read goljans book because there is a lot to explain about the differences and is very important for the exam. The hemoglobin dimers that remain in circulation are oxidized to methemoglobin, which disassociates into a free heme and globin chains.