Hemolytic Anemias (Chapter 9)

Defects of the RBC leads to:

Premature destruction & hemolysis

Hemolytic anemias

Disorders associated with both: intrinsic (intracorpuscular) defects of the RBC and extrensic (extracorpuscular) abnormality

Intracorpuscular

Caused by defect inside the RBC

Extracorpuscular

Caused by factors outside the RBC

The most frequent tests used to reflect increased red cell destruction are:

• Unconjugated (indirect) bilirubin

• Serum haptoglobin (binds free Hgb in blood)

Coombs’ test

Establish cause of hemolysis

Coombs’ test - positive means:

The hemolysis is caused by the immune system (antibodies)

Coombs’ test - negative means:

Hemolysis is not caused by antibodies. Further divided into:

• Smear positive

• Smear negative/nonspecific

Smear-positive

Abnormal RBC morphology visible; hemolysis due to RBC membrane damage/fragmentation

Smear-negative/nonspecific

No clear smear findings, other causes like enzyme defects

Hereditary spherocytosis (HS)

Decreases amounts of spectrin, ankyrin, AE1, or protein 4.2

Patients with HS who test for osmotic fragility should show

Increased

Patients with HS who test for Glycerol lysis should show

Increased

Patients with HS who test for Eosin 5’Maleimide Flow Cytometry should show:

Lower fluorescence

Hereditary Elliptocytosis is characterized by:

The presence of elliptical RBCs

What disease could cause this?

Hereditary elliptocytosis

Southeast Asian Ovalocytosis (SAO)

Very common in Melanesian & other Southeast Asian population groups due to the protective effect toward malarial parasites

What condition could cause this?

Southeast Asian Ovalocytosis

Alterations in the permeability of the RBC membrane to cations affect:

RBC hydration

Hereditary hydrocytosis (stomatocytosis)

RBCs are swollen

Hereditary Xerocytosis

RBCs are markedly dehydrated

What condition could possibly cause this?

Hereditary hydrocytosis

What condition could possibly cause this?

Hereditary xerocytosis

Passive sodium leak, increases the sodium & water content; causes macrocytosis is a characteristic of:

Hereditary hydrocytosis

The presence of stomatocytes can indicate:

Hereditary hydrocytosis

A smear with target cells present can possibly indicate:

Hereditary xerocytosis

Uneven Hgb distribution (caused by Hereditary Xerocytosis)

Cells with hemoglobin concentrated in one part of the cell (puddled)