Microangiopathic hemolytic anemia (MAHA) is a microangiopathic subgroup of

hemolytic anemia Hemolytic anemia or haemolytic anaemia 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). This most commonly ...

(loss of red blood cells through destruction) caused by factors in the small blood vessels. It is identified by the finding of anemia and schistocytes on

microscopy Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of micr ...

of the

blood film A blood smear, peripheral blood smear or blood film is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood smears are examined in the ...

Signs and symptoms

In diseases such as

hemolytic uremic syndrome Hemolysis or haemolysis (), also known by several other names, is the rupturing ( lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...

disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts o ...

thrombotic thrombocytopenic purpura Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in blood clots forming in small blood vessels throughout the body. This results in a low platelet count, low red blood cells due to their breakdown, and often kidney, h ...

, and malignant hypertension, the endothelial layer of small vessels is damaged with resulting fibrin deposition and platelet aggregation. As red blood cells travel through these damaged vessels, they are fragmented resulting in intravascular hemolysis. The resulting

schistocyte A schistocyte or schizocyte (from Greek for "divided" and for "hollow" or "cell") is a fragmented part of a red blood cell. Schistocytes are typically irregularly shaped, jagged, and have two pointed ends. Several microangiopathic diseases, ...

s (red cell fragments) are also increasingly targeted for destruction by the reticuloendothelial system in the spleen, due to their narrow passage through obstructed vessel lumina. It is seen in

systemic lupus erythematosus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...

, where immune complexes aggregate with platelets, forming intravascular thrombi. Microangiopathic hemolytic anemia is also seen in

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

. Microangiopathic hemolytic anemia may be suspected based on routine medical laboratory tests such as a CBC (complete blood cell count).

Automated analyser An automated analyser is a medical laboratory instrument designed to measure different chemicals and other characteristics in a number of biological samples quickly, with minimal human assistance. These measured properties of blood and other fluids ...

s (the machines that perform routine

full blood count A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and plat ...

s in most hospitals) are designed to flag blood specimens that contain abnormal amounts of red blood cell fragments or ''schistocytes''.

Causes

Disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body, blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts o ...

HELLP syndrome HELLP syndrome is a complication of pregnancy; the acronym stands for hemolysis, elevated liver enzymes, and low platelet count. It usually begins during the last three months of pregnancy or shortly after childbirth. Symptoms may include feelin ...

Thrombotic thrombocytopenic purpura Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that results in blood clots forming in small blood vessels throughout the body. This results in a low platelet count, low red blood cells due to their breakdown, and often kidney, h ...

Hemolytic uremic syndrome Hemolysis or haemolysis (), also known by several other names, is the rupturing ( lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo ...

Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

Malignant hypertension A hypertensive emergency is very high blood pressure with potentially life-threatening symptoms and signs of acute damage to one or more organ systems (especially brain, eyes, heart, aorta, or kidneys). It is different from a hypertensive urgency ...

* Scleroderma renal crisis * Malfunctioning cardiac valves (called the "Waring Blender syndrome") *

Kasabach–Merritt syndrome Kasabach–Merritt syndrome, also known as hemangioma with thrombocytopenia, is a rare disease, usually of infants, in which a vascular tumor leads to decreased platelet counts and sometimes other bleeding problems, which can be life-threatening. ...

* Insertion of foreign bodies * Drugs (e.g. cancer

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...

) * others diseases:

eclampsia Eclampsia is the onset of seizures (convulsions) in a woman with pre-eclampsia. Pre-eclampsia is one of the hypertensive disorders of pregnancy that presents with three main features: new onset of high blood pressure, large amounts of protein in ...

, renal allograft rejection,

paroxysmal nocturnal hemoglobinuria Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the body's innate immune system. This destructive process occu ...

scleroderma Scleroderma is a group of autoimmune diseases that may result in changes to the skin, blood vessels, muscles, and internal organs. The disease can be either localized to the skin or involve other organs, as well. Symptoms may include areas of ...

, and vasculitides such as

polyarteritis nodosa Polyarteritis nodosa (PAN) is a systemic necrotizing inflammation of blood vessels (vasculitis) affecting medium-sized muscular arteries, typically involving the arteries of the kidneys and other internal organs but generally sparing the lungs' ...

and

granulomatosis with polyangiitis Granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis (WG), is a rare long-term systemic disorder that involves the formation of granulomas and inflammation of blood vessels (vasculitis). It is a form of vasculitis ...

antiphospholipid syndrome Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS provokes blood clots (thrombosis) in both arteries and veins as well as pregnancy- ...

Pathophysiology

In all causes, the mechanism of MAHA is the formation of a

fibrin Fibrin (also called Factor Ia) is a fibrous, non-globular protein involved in the clotting of blood. It is formed by the action of the protease thrombin on fibrinogen, which causes it to polymerize. The polymerized fibrin, together with platele ...

mesh due to increased activation of the system of

coagulation Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism o ...

. The red blood cells are physically cut by these protein networks. The resulting fragments are the schistocytes observed in light m DIC With Microangiopathic Hemolytic Anemia

DIC With Microangiopathic Hemolytic Anemia

Diagnosis

Microangiopathic hemolytic anemia results in isolated increase in serum bilirubin levels. Unconjugated hyperbilirubinemia above 15% is present. The differential diagnoses are

rifampicin Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), mycobacterium avium complex, ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. ...

probenecid Probenecid, also sold under the brand name Probalan, is a medication that increases uric acid excretion in the urine. It is primarily used in treating gout and hyperuricemia. Probenecid was developed as an alternative to caronamide to competitive ...

use, inherited disorders like

Gilbert's syndrome Gilbert syndrome (GS) is a syndrome in which the liver of affected individuals processes bilirubin more slowly than the majority. Many people never have symptoms. Occasionally jaundice (a slight yellowish color of the skin or whites of the eyes) ...

and other hemolytic disorders. On Peripheral smear fragmented Burr and helmet shaped RBC are seen

Treatment

Platelets and cryoprecipitate are contraindicated as they facilitate further clot formation and RBC lysis. Plasmapheresis is one treatment for TTP; corticosteroids should also be considered.

References

External links

Nephrology Acquired hemolytic anemia {{circulatory-stub