Part 20. Diseases of the Blood Flashcards
Except Anemias
Pancytopenia with hypocellular BM is seen in what conditions?
give 3
- inherited bone marrow failure syndromes (IBMFSs) with pancytopenia
- acquired aplastic anemia of varied etiologies, and
- the hypoplastic variant of myelodysplastic syndrome (MDS)
Pancytopenia with cellular BM is seen with?
give at least 5
- primary bone marrow disease (e.g., acute leukemia, myelodysplasia)
- secondary to autoimmune disorders (e.g., autoimmune lymphoproliferative syndrome, systemic lupus erythematosus)
- vitamin B12 or folate deficiency,
- storage diseases (e.g., Gaucher, Niemann-Pick)
- overwhelming infection
- sarcoidosis, and
- hypersplenism
Pancytopenia with BM infiltration can be seen in?
- metastatic solid tumors
- myelofibrosis
- hemophagocytic lymphohistiocytosis
- osteopetrosis
What condition is considered the most common of the inherited pancytopenias?
Fanconi Anemia
Pattern of inheritance of Fanconi Anemia
autosomal recessive
one uncommon form is X-linked recessive
True or False
Patients with Fanconi Anemia have a predisposition to malignancy, including myelodysplasia (MDS), acute myeloid leukemia (AML), and epithelial cancers.
True
The classic Fanconi Anemia phenotype includes the triad of?
- Bone Marrow Failure
- Congenital anomalies
- Elevated chromosomal fragility
The most common congenital anomalies in Fanconi anemia involves which system?
skeletal and include absence of radii and/or thumbs that are hypoplastic, supernumerary, bifid, or absent.
Characteristic facial dysmorphisms found in many patients with Fanconi anemia.
microcephaly, small eyes, epicanthal folds, and abnormal shape, size, or positioning of the ears
The most frequent solid tumors assoc with Fanconi Anemia are
- squamous cell carcinomas (SCCs) of the head and neck (600-fold higher risk than the general population)
- and carcinoma of the upper esophagus (2000-fold higher risk), the vulva (3000-fold higher risk), and/or anus, cervix, and lower esophagus.
Diagnosis of Fanconi Anemia can be confirmed with?
Lymphocyte chromosomal breakage study done with and without the addition of cross-linking agents such as DEB (diepoxybutane) and MMC (mitomycin C), the latter will test for chromosomal fragility
The only curative therapy for the hematologic abnormalities observed in FA patients
HSCT
What therapy is not curative for FA but is used rather as a bridge while waiting for a suitable donor?
Androgen therapy.
Oral oxymetholone and danazol are the 2 most commonly used androgenic drugs.
Side effects of androgens include masculinization, increased linear growth, increased mood swings or aggressiveness, elevated hepatic enzymes, cholestasis, peliosis hepatis (blood-filled hepatic sinusoids), and liver tumors
What is the underlying defect in Schwachman-Diamond Syndrome?
Ribosomopathy, defect in ribosome assembly
Pattern of inheritance of SDS?
Autosomal recessive
What are the defining features of SDS?
Hematologic abnormalities (most common neutropenia) and exocrine pancreatic insufficiency (causing fat malabsorption)
Tests that can be used to determine pancreatic insufficiency in SDS?
Serum trypsinogen (low), pancreatic isomylase (low),
fecal elastase (low)
What are similarities and distinguishing features of SDS from FA?
SDS shares some manifestations with Fanconi anemia, such as bone marrow dysfunction and growth failure, but patients with SDS are readily distinguished because of pancreatic insufficiency with fat malabsorption, fatty changes within the pancreatic body visualized by imaging, characteristic skeletal abnormalities not seen in FA, and a normal chromosomal breakage study with DEB and MMC.
Treatment for SDS
Pancreatic insufficiency : oral pancreatic enzymes and fat soluble vitamins
SEvere neutropenia : GCSF
Severe BM failure : allogenic HSCT
The diagnostic triad of mucocutaneous features of dyskeratosis congenita.
- dysplastic nails
- lacy reticular pigmentation of the upper chest &/or neck
- oral leukoplakia
However, the triad is not present in all individuals. If it occurs, skin and nail findings usually become apparent in the 1st 10 yr of life, whereas oral leukoplakia may be noticed later.
Etiology of Dyskeratosis congenita
multisystem telomere disorder
Clinical criteria for classic DC?
Presence of at least 2 of the 4 major features—abnormal skin pigmentation, nail dystrophy, leukoplakia, and bone marrow failure—and 2 or more of the other somatic features known to occur in DC.
In classic disease, skin pigmentation and nail changes typically appear first, usually in the 1st decade of life. Bone marrow failure usually develops within the 1st 2 decades, with 80% of patients developing bone marrow failure by age 30 yr and almost 90% of patients having bone marrow failure at some point in their life.
The initial hematologic change in DC?
The initial hematologic change in DC is usually thrombocytopenia, anemia, or both, followed by pancytopenia and aplastic anemia. The red cells are often macrocytic, and the fetal hemoglobin is elevated. Initial bone marrow specimens may be normocellular or hypercellular, but with time, a symmetric depletion of all hematopoietic lineages ensues.
Distinguishing features of DC against FA.
nail dystrophy, leukoplakia, tooth abnormalities, hyperhidrosis of the palms and soles, and hair loss.
This condition typically manifests in infancy as isolated thrombocy- topenia caused by reduction or absence of bone marrow megakaryocytes with initial preservation of granulopoietic and erythroid lineages.
Congenital Amegakaryocytic Thrombocytopenia (CAMT)
Autosomal recessive
Most common anomalies associated with CAMT
Body system
Neurologic - developmental delay is a prominent feature
Cardiac - CHDs
Hallmark of aplastic anemia
peripheral pancytopenia, coupled with hypoplastic or aplastic bone marrow
The presence of ____ is suggestive of congenital pancytopenia but is not diagnostic
Fetal hemoglobin
For patients with acquired aplastic anemia without a sibling donor, the major form of therapy is?
immunosuppression with horse antithymocyte globulin (ATG) and cyclosporine
(median time to response is 6mos)
These hematologic disorders in Down Syndrome patients does not require aggressive therapeutic approach as these diseases in this specific population are very responsive to conventional chemotherapy
Myelodysplastic syndrome (MDS) and Acute myelocytic Leukemia (AML)
In the preoperative period, Hb level ____ is an acceptable level
> = 7g/dL
Blood transfusion may be indicated in the treatment of hemorrhage if estimated blood loss is ____ % of the circulating blood volume and the pt’s condition is unstable despite initial IV fluids
> 25%
Preoperative autologous blood collections from the patient occur up to ____wk before the surgery
6
For children and adolescents with overt bleeding, therapeutic PLT transfusions should be given when the blood PLT count falls below ____ × 10^9/L and repeated as needed to maintain the PLT count at this level during bleeding and for 48 hr after bleeding ceases to allow the clot to “stabilize.”
50
For a major invasive procedure (e.g., surgical), the PLT count should be maintained >____ × 10^9/L until any bleeding that occurs ceases and the patient is stable.
50
The risk of spontaneous bleeding increases when blood PLT levels fall to < ____ × 10^9/L, particularly when hemorrhagic risk factors are present.
20
When managing patients with PLT dysfunction, it is important to remember that an abnormal test result with a modern PLT function device or, historically, a ____ more than twice the upper limit of normal provides diagnostic evidence of PLT dysfunction.
Bleeding time
Thrombopoietin (TPO) levels are ____ in healthy neonates than in older individuals
higher or lower?
higher
PLT counts < ____ × 109/L pose significant clinical risks for premature neonates.
100
Dosing of PLT concentrates or pheresed PLTs for children weighing up to 30kg?
5-10 mL/kg
PLT transfusion rate
may be transfused as rapidly as the patient’s overall condition permits, certainly within 2 hr, but not longer than 4 hr.
For those infants weighing < 1500 g at birth, what is recommended to prevent transfusion-associated GVHD?
Irradiation
When is granulocyte transfusion (GTX) recommended?
only when serious infections are clearly unresponsive to antimicrobial drugs
Transfusion of plasma is efficacious for the treatment of deficiencies in clotting factors ?
II, V, X, XI
Cryoprecipitate can be used to treat deficiency of ?
Factor XIII and fibrinogen
What is an important indication for plasma transfusion?
For rapid reversal of the effects of warfarin in patients who are actively bleeding or who require emergency surgery (in whom functional deficiencies of vitamin K–dependent factors II, VII, IX, and X cannot be rapidly reversed by vitamin K administration)
Indications for plasma transfusion in neonates
4
(1) reconstitution of red blood cell (RBC) concentrates to simulate whole blood for use in massive transfusions (exchange transfusion, cardiac bypass surgery, and extracorporeal membrane oxygenation),
(2) hemorrhage secondary to vitamin K deficiency
(3) disseminated intravascular coagulation with bleeding, and
(4) bleeding in congenital coagulation factor deficiency when more specific treatment is either unavailable or inappropriate
What is the most efficacious method currently available to prevent transfusion-transmitted CMV?
perform leukoreduction in the blood center/bank without regard for the CMV antibody status of the donor
How may the risk of transfusion-related acute lung injury (TRALI) be reduced?
by avoiding transfusion of plasma or platelets from female donors, who were possibly alloimmunized to leukocyte antigens during pregnancy, or by selecting donors (e.g., males) who are likely to be negative for human leukocyte antigen (HLA) antibodies.
True or False
Leukocyte reduction can be substituted for irradiation to prevent GVHD.
False. It cannot, however, pathogen-reduction technologies have been demonstrated to be efficacious
Main components of the hemostatic process
5
- vessel walls
- platelets
- coagulation proteins
- anticoagulant proteins
- fibrinolytic system
Rate-limiting steps in the clotting process
those involving the cofactors factor VIII (X-ase complex) and factor V (pro- thrombinase complex)
- Antithrombin III (ATIII)
- Protein C
- Protein S
- Tissue Factor Pathway inhibitor )TFPI)
The 2 most common severe bleeding disorders
Factor VIII and Factor IX deficiencies
(Hemophilia A and B)
Patients with clotting factor deficiency usually have bleeding where?
deep bleeding into muscles and joints, with much more extensive ecchymoses and hematoma formation
Mucocutaneous bleeding may be a sign of?
defects in platelet-blood vessel wall interaction (vWD or platelet function defects)
True or False
Thrombocytosis in children is usually reactive and is not associated with bleeding or thrombotic complications.
True
This measures the activation of clotting by tissue factor (thromboplastin) in the presence of calcium.
Prothrombin time (PT)
This test measures the initiation of clotting at the level of factor XII through sequential steps to the final clot end-point.
Partial thromboplastin time (PTT)
The PTT can be prolonged by deficiencies of?
factor XII, prekallikrein, and high-molecular-weight kininogen, yet these deficiencies do not result in bleeding
This measures the final step in the clotting cascade, in which fibrinogen is converted to fibrin
Thrombin time (TT)
PT tests for which coagulation factors?
II, V, VII, X (extrinsic pathway)
PTT tests for coagulation factors?
VIII, IX, XI, XII (intrinsic pathway)
Prolongation of TT occurs with what conditions?
reduced fibrinogen levels (hypofibrinogenemia or afibrinogenemia), with dysfunctional fibrinogen (dysfibrinogenemia), or in the presence of substances that interfere with fibrin polymerization, such as heparin and fibrin split products
When a qualitative platelet function defect is suspected, what is usually ordered?
platelet aggregation testing
Hallmark of hemophilic bleeding.
Hemarthrosis
The earliest joint hemorrhages in hemophilic patients appear most often where?
ankle
A pt with hemophilia may lose large volumes of blood into which muscle verging on hypovolemic shock, with only a vague area of referred pain in the groin?
Iliopsoas
What are the classifications of Hemophilia according to severity and briefly describe each.
__Severe__: having < 1% activity of the specific clotting factor, and bleeding is often spontaneous
__Moderate__: factor levels of 1–5% and usually require mild trauma to induce bleeding.
__Mild__: levels >5%, may go many years before the condition is diagnosed, and frequently require significant trauma to cause bleeding.
The hemostatic level for factor VIII is > ____, and for factor IX is > ____.
30-40%
25-30%
Mode of inheritance of hemophilia A
X-linked recessive
Mode of inheritance of Hemophilia B
X-linked recessive