Feature of chronic extravascular hemolysis

 # Which one of the following is a feature of chronic extravascular hemolysis? 

a. Raised serum conjugated bilirubin 

b. Low reticulocyte count 

c. Hypocellular bone marrow 

d. Gall stones

The correct answer is D. Gall stones.

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). This most commonly occurs within the spleen, but also can occur in the reticuloendothelial system or mechanically (prosthetic valve damage). Hemolytic anemia accounts for 5% of all existing anemias.  It has numerous possible consequences, ranging from general symptoms to life-threatening systemic effects. The general classification of hemolytic anemia is either intrinsic or extrinsic. Treatment depends on the type and cause of the hemolytic anemia.

Symptoms of hemolytic anemia are similar to other forms of anemia (fatigue and shortness of breath), but in addition, the breakdown of red cells leads to jaundice and increases the risk of particular long-term complications, such as gallstones and pulmonary hypertension. 

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Iron absorption will be increased in:

 # Iron absorption will be increased in: 

a. Pregnancy 

b. Chronic inflammation 

c. Iron overload 

d. Phosphates

The correct answer is A. Pregnancy.

Factors that increase iron absorption from GI tracts are:

• Dietary factors

• Increased heme iron (particularly in meat)

• Ferrous iron salts

• GI factors

         – Acid pH

• Increased requirement:

         – Iron deficiency

         – Increased erythropoiesis

         – Pregnancy

         – Hypoxia

Factors that decrease iron absorption are:

• Ferric iron salts

• Malabsorption

• Proximal bowel resection

• Presence of oxalates, phytates and phosphates in diet

• Inflammatory disorders (due to increased hepcidin level)

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First stage of iron deficiency:

 # Which is the first stage of iron deficiency? 

a. Negative iron balance 

b. Decreased iron stores 

c. Decrease MCV 

d. Decrease in Hemoglobin

The correct answer is A. Negative Iron Balance.

“Negative iron balance” describes a state in which body iron content is decreasing, secondary to relative decreases in iron intake and/or relative increases in iron losses. Over time, negative iron balance can progress to functional and absolute iron deficiency and anemia.

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Earliest recognizable change in RBC morphology:

 # Which of the following is earliest recognizable change in RBC morphology in case of iron deficiency? 

a. Hypochromia 

b. Anisocytosis 

c. Target cells 

d. Poikilocytosis

The correct answer is B. Anisocytosis. 

Anisocytosis is the medical term for having red blood cells (RBCs) that are unequal in size. Normally, a person’s RBCs should all be roughly the same size.

Anisocytosis is usually caused by another medical condition called anemia. It may also be caused other blood diseases or by certain drugs used to treat cancer. For this reason, the presence of anisocytosis is often helpful in diagnosing blood disorders like anemia.

Treatment for anisocytosis depends on the cause. The condition isn’t dangerous on its own, but it does indicate an underlying problem with the RBCs.

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Least implicated in the pathophysiology of sickle cell disease:

 # Which is least implicated in the pathophysiology of sickle cell disease? 

a. Neutrophils 

b. Nitric oxide 

c. Platelets and coagulation factors 

d. Free hemoglobin

The correct answer is C. Platelets and Coagulation factor.

The pathophysiologic processes that lead to sickle cell disease related complications result from a combination of hemolysis and vaso-occlusion. Hemolysis occurs as a result of repeated episodes of hemoglobin polymerization/depolymerization as sickle red blood cells pick up and release oxygen in the circulation. Red blood cell membranes become abnormal from this process and red blood cells have a shortened lifespan. 

Hemolysis can occur both chronically and during acute painful vaso-occlusive crises and also results in the release of substantial quantities of free hemoglobin into the vasculature. The consumption of significant quantities of nitric oxide (NO) by this resultant free ferrous hemoglobin,  in turn, leads to abnormal regulation in vascular homeostasis. Moreover, neutrophils play a key role in the tissue damage which occurs as both neutrophil numbers are increased and evidence suggests that they are abnormally activated and adherent. Likewise, as suggested by recent data sickle red cells induce adhesion of lymphocytes and monocytes to the endothelium such that these may contribute to the pathogenesis of vascular occlusion. Platelet activation also occurs in SCD but is least implicated among the given options.

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High risk during surgery:

 # Which of the following may constitute high-risk during surgery? 

a. β-Thalasemia minor 

b. Hb S homozygous 

c. Hb D Punjab

d. Hb E trait

 

The correct answer is B. Hb S homozygous.

Hb D Punjab and Hb D Los Angeles are having same biochemical structure (Glutamic acid is replaced by Lysine at 121 position in β chain). Heterozygous state is essentially asymptomatic. Homozygous Hb D is very rare. Sickle cell disease is relatively less associated with by Hb S/D Punjab/Los Angeles . Mutation in β chain by virtue of which glutamic acid is replaced by lysine at 26th position in β chain causes Hb E. In Hb E carrier state, 30–45% of the Hb is Hb E, and such carriers are asymptomatic but shows microcytosis. Homozygons E disease is associated with marked microcytosis and hypochromia, but the anemia is usually mild. Clinically resembles β-thalassemia minor. Hb E with Hb D heterozygous state is variable in severity.

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The duffy blood group system is functionally associated with:

# The duffy blood group system is functionally associated with:

a. Invasion by P. falciparum

b. Red cell urea transporter

c. Maintenance of membrane integrity

d. Invasion by P. vivax

The correct answer is: D. Invasion by P. vivax.

Duffy antigen is a receptor for Plasmodium vivax.

• The receptor for P. falciparum on RBCs are glycophorins

• Red cell urea transporter is the Kidd antigen and its absence can be associated with impaired urea transport and urine concentrating defect.

• Integral membrane proteins are band 3, glycophorins, Rh, Kell,  Kidd, Duffy and Lutheran glycoproteins. Though Duffy is an integral membrane protein but it is not the major protein involved in the overall integrity of RBC membrane.

• The peripheral membrane proteins are spectrin, ankyrin, actin, protein 4.1, 4.2 and 4.9, p 55 and the adducins.

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