DONE BY : BUTHANINAH-MFM , TALA SAMOUR &RaSHA RAKAN

Hemolytic anemias (1 of 2)

Overview

• = anemias due to accelerated red cell destruction

……may be due to

intrinsic (intracorpuscular) red

cell defects…usually inherited

or

extrinsic (extracorpuscular)

factors…usually acquired

نبدأ بسم هللا الرحمن الرحم RBC destructionوهو عباره عن hemolytic anemiasسمى ال anemiaف نوع من انواع ال *

or hemolysis ,also acceleration of RBC destruction in another meaning it’s life span is short .

Hemolytic anemias > two types :

1-Intrinsic (intracorpuscular) مشكله من داخل الخلة نفسها ادى الى تحطمها

a)Hereditary ex:spherocytosis it is problem in plasma membrane cytoskeleton وصبح شكل الخلة كروة

.وتصبح الخلة هنا بضاوة elliptocytosis ووهنالك ش شبهها ولكن لن نتطرق له ه

b)Enzyme defect ex:G6PD

c)Abnormal structure of hemoglobin (hemoglobinopathies) ex: sickle cell anemia and decrease of globin synthesis (thalassemia )

d)Acquired ex :membrane defect (paroxysmal nocturnal hemoglobinuria)

2- extrinsic (extracorpuscular) ش من الخارج ادة الى تحطمها

a)Anti-immunity problems ex :antibody mediated

b)Mechanical trauma to red cells خالل مرورها باالوعة الدموه

c) Infection (malaria)

Overview, cont’d

• Erythropoietin release from the kidney

growth of erythroid elements + increased release of reticulocytes

from the bone marrow

pre-mature element in bloodفيزداد خروج ال

…so: erythroid hyperplasia and reticulocytosis are hallmarks of all

hemolytic anemias…may be also: extramedullary hematopoiesis

liver and spleen will be involved in this process and called extramedullary hematopoiesis

:يحدث بها التالي hemolytic anemiaجميع حاالت ال

A more clinical way to classify hemolytic anemias

• Extravascular hemolysis

…destruction of RBCs by phagocytes (mainly in spleen)

or

• Intravascular hemolysis…within the

circulation *Direct damage, examples: -mechanical forces (e.g., defective heart valve) -fixation of complement -bacterial toxins -heat

وهو اهم hemolytic anemia تصنف اخر•

(Extravascular hemolysis and Intravascular hemolysis)

.هو الطاغ extra وغالبا ما بكون ال,عادة ما حدثوا مع بعض ولكن هنالك انواع تطغى على االخرى•

حدث زادة تحطم لها spleenكرات الدم الحمراء تكون طبعه ولكن عند مرورها بال : extraمبدأ ال• macrophagesبواسطة ال

عبر ال spleenوه قدرتها على العبور من ال deformabilityكرات الدم الحمراء لها خاصه تسمى ال•sinusoid بدون حدوثtrapped ,اذا اذا قلت ال deformability تزداد الtrap لها بالspleen فزداد

macrophagesوهذا غر طبع النه ال macrophagesبواسطة ال phagocytesفرصت حدوث ال .الت انتهى عمرها فقط RBCجب ان تتخلص من ال

hemolysisحدث لها vassalوه تسبح بال spleenبدون مرورها بال: intraمبدأ ال•

•fixation of complement وهنا المقصود بالمراحل االخره late step من ال membrane attack complement (MAC) (cb5-c9)

Intravascular hemolysis <..حدث

Extravascular hemolysisحدث << early step (c3b) is stoppedاذا حدث بالمراحل المبكره •

macrophagesلحتى تم اكلها من ال RBCبمعنى اخر عمل عالمه على ال opsonizationهو c3bعمل ال •

Findings that distinguish intravascular hemolysis from extravascular hemolysis

• Hemoglobinemia, hemoglobinuria, and hemosiderinuria…intravascular hemolysis

• Loss of iron…intravascular hemolysis

…by contrast, in extravascular hemolysis: iron recycling by phagocytes

is very efficient

• No splenomegaly…intravascular hemolysis so just in extra

**Both extra- and intravascular pathways of hemolysis cause decreased serum

levels of haptoglobin and both cause jaundice( الرقان او صفار) and pigment cholelithiasis.

jaundiceالذي زداد ف هذه الحالة و سبب ال وو ه indirect -2و ....direct-1نوعن bilirubinال *

hemolytic anemiaنشك بال choleithiasis))عندما أت مرض شاب لده مراره

pigmented stonesزداد حدوث ال hemolytic anemiesف ال *

الدكتور هنا نبه على حفظ

هذه الساليده بدون

التعمق فيها

Hereditary Spherocytosis • Nondeformable cells…sequestration and destruction in the spleen

• Usually: autosomal dominant ( In most cases)

…a more severe, autosomal recessive form in minority of patients

Intrinsic problem in the membrane lead to accelerating early RBCs destruction by macrophages .

In sever cases

So it will be trapped more by spleen

Heredity Spherocytosis

• There is protein up between the cell & membrane, the most important are Ankyrin ,Band3,Spectrin .If any problem got them that lead to increase

عن الهكل داخل الخلة بحث صبح اجزاء من الغشاء تفلت الغشاء احتمالة انفصال

• So… جزء من الغشاء نفصل عن ال

Cytoskeleton and lost so finally the cell will be spherical & the surface area decrease…..> ‘Nondeformable cells’ so the spleen got them and the macrophages hemolysis them in early time before they become old…>EXTRAVASCULAR Hemolysis .

Hereditary Spherocytosis, cont’d

• Splenomegaly is more common and prominent than in any other form of hemolytic anemia

• Beneficial effect of splenectomy…partial splenectomy is better, Why?

• Morphology: dark red and lack central pallor

• Cholelithiasis.. in 40% to 50% of patients

• Anemia

• Jaundice

• RBCs show osmotic fragility when placed in hypotonic salt solutions

The most type of extravascular hemolysis that cause splenomegaly So splenectomy is useful but the spleen is important in defence against encapsulated bacteria so there is something called partial splenectomy

Pigmented choleithiasis because of increased indirect bilirubin

If you put the cell in hypotonic solution the cell will lysis (more prone ) Increased osmotic fragility

Hereditary Spherocytosis, cont’d

• Stable clinical course…may be punctuated by aplastic crises

…the most severe of which are triggered by parvovirus B19 infection

…marked tropism for erythroblasts …until the immune response controls the infection (usually in 10–14 days), the marrow may be virtually devoid of red cell progenitors …blood transfusions may be needed to support patients until the infection is cleared

بضرب ال erythrocyte

رح يبطل يصنع الخاليا التعويضية الي كان يصنعها بعد

ما يروح الInfection برجع ال

bone marrow make erythrocyte

Glucose-6-Phosphate Dehydrogenase Deficiency

• Normally: reduced glutathione (GSH) inactivates endogenous and exogenous oxidants

• The abnormality here affects the enzyme responsible for the synthesis of GSH…G6PD (on X chromosome)

• Many variants of G6PD and few of them are associated with the disease

• Of the variants: G6PD A-…10% of black males in USA

…normal activity but decreased half-life

…the problem appears in older cells

Intrinsic problem

Which important in defence against oxygen reactive species

الخلية ما رح تقدر تقاوم ال Oxidative stress that happen

مريض التفول يزداد عنده ال Reactive oxygen species So he are not eating beans to avoid hemolysis

Of the enyzme

Intravascular hemolysis

Haemoglobin in RBCs…>oxidation…>denaturation of haemoglobin …>collect like bodies in the cells…>we called them Heniz bodies

G6PD deficiency, cont’d

• Transient episodes of intravascular hemolysis caused by exposure to an environmental factor (usually infectious agents or drugs)

• Examples of drugs: antimalarials (e.g., primaquine), sulfonamides, nitrofurantoin, phenacetin, aspirin (in large doses), and vitamin K derivatives

…infections are more common to cause the episodes

• Oxidized hemoglobin denatures and accumulates as “Heinz bodies”

these will damage the RBC membrane…intravascular hemolysis

Heinz bodies and bite cells These will be trapped in the spleen…so we have also extravascular hemolysis

The macrophages may come and pulls out heniz bodies…>so the cell be like bite cells…>so they ’مأكولة‘trapped and sequestrated in spleen …>extravascular hemolysis.

G6PD deficiency, cont’d

• Hemolysis typically develops 2 or 3 days after drug exposure

• The red cells of affected males are uniformly deficient and vulnerable to oxidant injury

• Random inactivation of one X chromosome in heterozygous females creates two populations of red cells, one normal and the other G6PD-deficient

• Most carrier females are unaffected except for those with a large proportion of deficient red cells (a chance situation known as unfavorable lyonization)

Males more likely to develop G6PD deficiency .

X خاليا تكون متأثرة النها التغى فيها ال الغير مضروب و خاليا اخرى سليمة حدث فيها العكس

X معظم خاليا جسمهم التغى فيها ال

المش مضروب

G6PD deficiency, cont’d

• In the case of the G6PD A− variant, it is mainly older red cells that are susceptible to lysis

…Because the marrow compensates for the anemia by increasing

its production of new red cells with adequate levels of G6PD, the

hemolysis abates even if the drug exposure continues

• G6PD Mediterranean variant:

…more severe deficiency and more severe hemolysis

The attack will be temporary because the cell that lysed are the old one and the patient has compensatory cells from the bone marrow

<The worst type >

Paroxysmal Nocturnal Hemoglobinuria (PNH)

• Acquired mutations in PIGA, a gene required for the synthesis of phosphatidylinositol glycan (PIG) is located in the cell memebrane, which serves as a membrane anchor for many proteins and among them proteins inhibits complement fixation Isn’t congenital, almost always acquired

• X-linked…normal cells have only one active PIGA gene, a mutation of which is sufficient to cause PIGA deficiency

• Mutations in PNH occur in an early hematopoietic progenitor that is capable of giving rise to red cells, leukocytes, and platelets affects the precursors of all the cells not just erythrocytes

…the resulting progeny lack the ability to make “PIG-tailed” proteins bind to PIG tail,

including several that limit the activity of complement…so??? so if it was mutated, these proteins won’t bind and complement fixation increases more hemolysis

PNH, cont’d • RBCs in this case are more sensitive than the affected WBCs but the progenitor of both of them is

affected

• Nocturnal hemolysis attacks in the night …because complement fixation is more with low pH more CO2 and more acidosis They are more sensitive to complement fixation because they can’t resist it

• Most patients: only anemia and iron deficiency

• The most feared complication of PNH is thrombosis

…often occurs within abdominal vessels such as the portal vein and

the hepatic vein

…Eculizimab against MAC last steps, an antibody that binds C5 and inhibits the assembly of

the C5b–C9 membrane attack complex…effective intravascular hemolysis

…doesn’t affect early phases of complement fixation…C3b deposition will

cause some degree of extravascular hemolysis

…all treated patients must be vaccinated against meningococci because MAC has an important effect on Neisseria meningitis, so the patients who take eculizimab are exposed to the danger of the infection because it stops MAC

Immunohemolytic Anemia antibody binds to antigen on the RBCs

surface It could be because of infection that mad the antibodies to attack RBCs by mistake It could have another reasons This type is followed by complement system (classical pathway), that’s triggered by Ab-Ag complex accumulation

• Antibodies bind to RBC membrane

• Diagnosis depends on the detection of antibodies and/or complement on red cells

…using Coombs test:

1-Direct Coombs test We take RBCs and we direct antibodies (anti-Ig) against antibodies (Ig) that are possibly present on RBCs, if the result was +ve (coagulation) that means there’s antibodies on the RBCs ( we already have the Ab-Ag complex)

2-Indirect Coombs test We take patients serum (plasma – coagulation factors) that possibly can contain antibodies and direct RBCs we have (not the patient’s) that has antigen for the possible antibodies (we form the Ab-Ag complex), then we direct Ab against the complex that we formed, if there was a coagulation that means the antibodies were present in the serum. We can know which Ab caused the problem.

Ab بالAgترتبط ال

داخل جسم المريض عاملة ، ونحن

نوجه لها أجسام مضادة ) أجسام

مضادة لالجسام المضادة( لنرى ان

كانت قد تكونت ام ال في جسمه

هنا نحن من قمنا بتكوين هذه ال

complexes

* extravascular hemolysis *

Immunohemolytic Anemia, cont’d

IgG or rarely IgA

More than 60% of the cases

Phagocytosis in the spleen …phagocytes cause changes in the membrane of RBCs resembling spherocytosis

Most patients: chronic mild anemia & splenomegaly…do not need treatment

Low affinity IgM ..bind at <30 degrees…distal body parts

IgM fixes complement but early steps not membrane attack complex (because of the low temperature)…opsonization by C3b and resultant phagocytosis

IgM also crosslinks red cells and causes them to clump (agglutinate). Sludging of blood in capillaries because of agglutination often produces Raynaud phenomenon

Binds to RBCs at 37 degrees That’s why they’re called warm

IgG is a good opsonin. I will cause opsonization of RBCs, and thus splenic macrophages will recognize them better

Even though it’s not hereditary spherocytosis, because these antibodies can destroy a part of cell membrane

IgM strongly triggers complement fixation

That’s why it likes to happen in the fingers, the nose, etc.

Hemolytic Anemia Resulting From Mechanical Trauma to Red Cells

• Defective cardiac valve prostheses as the RBCs passes through it, it causes turbulent flow because its hitting them

or

• Activity involving repeated physical pounding of one or more body parts (e.g., marathon racing, karate chopping, bongo drumming) sometimes it is called bongo drumming anemia

Intravascular hemolysis Repeated action that causes a mechanical force on RBCs and damages it

Microangiopathic hemolytic anemia…another hemolytic anemia resulting from mechanical trauma to red cells

…occurs in pathologic states in which small vessels become partially obstructed or

narrowed by lesions that predispose passing red cells to mechanical damage

…The most frequent of these conditions is disseminated intravascular coagulation (DIC)

…also:

• Malignant hypertension

• Systemic lupus erythematosus

• Thrombotic thrombocytopenic purpura (TTP)

• Hemolytic uremic syndrome (HUS)

• Disseminated cancer

A problem in the vessels, made them apply mechanical force on passing RBCs

Microangiopathic hemolytic anemia, cont’d

• Mechanical fragmentation of red cells = schistocytosis

…leads to the appearance of

characteristic “burr cells,” “helmet cells,”

and “triangle cells” in peripheral blood

smears

And any other mechanical hemolytic anemia that are mentioned in slide 22