Ch 14 Key Concepts

Question 1

caused by deficiencies of folate of vit B12 that lead to inadequate synthesis of thymidine and defective DNA replication

Answer 1

megaloblastic anemia

- results in enlarged abnormal hematopoietic precursors, ineffective hematopoiesis, macrocytic anemia, and pancytopenia

Question 2

what is vit B12 deficiency also associated with?

Answer 2

neurologic damage

- particularly in the posterior and lateral tracts of the spinal cord

Question 3

caused by chronic bleeding or inadequate iron intake

Answer 3

iron deficiency anemia

- results in insufficient hemoglobin synthesis and hypochromic, microcytic red cells

Question 4

caused by inflammatory cytokines, which increase hepcidin levels and thereby sequester iron in macrophages
- also suppress erythropoietin production

Answer 4

anemia of chronic disease

Question 5

caused by bone marrow failure (hypocellularity) due to diverse causes, including exposures to toxins and radiation, idiosyncratic reactions to drugs and viruses, and inherited defects in telomerase and DNA repair

Answer 5

aplastic anemia

Question 6

what are the two forms of pure red cell aplasia?

Answer 6

1. acute: parvovirus B19 infection
2. chronic: associated with thymoma, large granular lymphocytic leukemia, presence of neutralizing antibodies against erythropoietin, and other autoimmune phonemona

Question 7

what are the other causes of underproduction anemias?

Answer 7

marrow replacement (tumors, granulomatous disease; so-called myelophthisic anemias), renal failure, endocrine disorders, liver failure

Question 8

caused by autoantibodies against platelet antigens

- may be triggered by drugs, infections, lymphomas, or may be idiopathic

Answer 8

immune thrombocytopenia purpura

Question 9

what two disorders manifest with:

- thrombocytopenia, microangiopathic hemolytic anemia, and renal failure

Answer 9

thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Question 10

caused by acquired or inherited deficiencies of ADAMTS 13, a plasma metalloprotease that cleaves very-high molecular weight multimers of vWF

Answer 10

TTP

- fever and CNS involvement common

Question 11

what does deficiency of ADAMTS13 result in?

Answer 11

abnormally large vWF multimers that activate platelets

Question 12

caused by deficiencies of complement regulatory proteins or agents that damage endothelial cells, such as Shiga-like toxin elaborated by E.coli strain O157:H7

Answer 12

HUS

- the abnormalities initiate platelet activation, platelet aggregation, and microvascular thrombosis

Question 13

AD disorder caused by mutations in vWF, a large protein that promotes the adhesion of platelets to subendothelial collagen
- typically causes a mild to moderate bleeding disorder resembling that associated with thrombocytopenia

Answer 13

Von Willebrand disease

Question 14

X-linked disorder caused by mutations in factor 8

- affected males typically present with severe bleeding into soft tissues and joints have a PTT

Answer 14

hemophilia A

Question 15

X-linked disorder caused by mutations in coagulation factor 9
- clinically identical to hemophilia A

Answer 15

hemophilia B

Question 16

syndrome in which systemic activation of the coagulation leads to consumption of coagulation factors and platelets
- can produce bleeding, vascular occlusion, or tissue hypoxemia

Answer 16

disseminated intravascular coagulation

Question 17

what are the common triggers of disseminated intravascular coagulation?

Answer 17

sepsis, major trauma, certain cancers, obstetric complications