Hematologics Flashcards
Anemia definition:
reduction of either the number of RBCs, the amount of hemoglobin, or hematocrit (% of packed RBCs per deciliter of blood)
Definition of Sickle Cell Disease:
genetic disorder that results n chronic anemia, pain, disability, organ damage, increased risk for infection, and early death
Formation of abnormal hemoglobin chains - most common in Af. Americans
In normal hemoglobin, hemoglobin A(HbA) has
two alpha chains and two beta chains of amino acids
98-99% with a small % of fetal form of HbF
In SCD, what % is the total hemoglobin is composed of an abnormal beta chain?
40%
HbS - sensitive to low O2 content of RBCs
The clumped masses of sickled RBCs block blood flow is called what?
Vaso-occlusive event (VOE)
leads to hypoxia
The average life span of ab RBC conatining 40% or more of HbS is about how many days?
10-20 days – causes hemolytic (cell-destroying) anemia in patients with SCD
normal life span of RBCs
120 days
Patients with SCD has periodic episodes of extensive cellular sickling called what?
Crises –lead to hypoxemia (deficit of O2 in blood)
Etiology of SCD
Autosomal recessive pattern of inheritance
Specific mutation on chromosome 11
AS:
Sickle cell trait: occurs when one normal gene allele and one abnormal gene allele for hemoglobin are inherited and only half of the hemoglobin chains are abnormal
History of SCD:
Long sanding diagnosis
Usually has no manifestations other than presence of HbS
-Determine the patient’s energy level using a scale ranging from 0 to 10 to access degree of fatigue
What is the most common manifestation of SCD crisis?
pain
Physical assessments of SCD include:
Cardiovascular changes Priapism Skin changes Abdominal changes Kidney and urinary changes Musculoskeletal changes CNS changes
Cardiovascular changes: SCD
risk for high output heart failure
Priapism: SCD
prolonged penile erection that can occur to men with SCD
Skin changes: SCD
include pallor or cyanosis because of poor gas exchange from decreased perfusion and anemia
plus Jaundice results from RBC destruction and release of bilirubin
Abdominal changes: SCD
damage to the spleen and liver, occurs often early from many episodes of hypoxia and ischemia
Kidney and urinary changes: SCD
common as a result of poor perfusion and decreased tissue gas exchange
Musculoskeletal change: SCD
occur because arms and legs are often sites of blood vessel occlusion
CNS changes: SCD
During crisis, patients may have a low grade fever, if CNS has infarcts or repeated episodes of hypoxia, patients may have seizures or manifestations of a stroke
Assess for presence of “pronator drift” bilateral hand grasp strength, gait, and coordination
Psychosocial assessment: SCD
Often behavior changes are early manifestations of cerebral hypoxia from poor perfusion
Lab assessment: SCD
The diagnosis of SCD is based on the percentage of hemoglobin S on electrophoresis
AS is usually less than 40% HbS, and does not change during crisis
what count is usually high in SCD?
WBCs
Imaging assessment: SCD
Bone changes occur as a result of chronically stimulated marrow and low bone O2 levels
Skull= crew cut appearance on x-ray
x-rays of joints may show necrosis and desruction
MRIs may show soft tissue and organ changes from poor perfusion and chronic inflammation
Other diagnostic testing: SCD
ECGs document cardiac infarcts and tissue damage
-may show cardiomyopahy and decreased cardiac output
Managing pain of SCD:
Mild pain = managed at home
Severe pain = require hospitalization and opioid analgesics
-Drug therapies, hydration, and complementary therapies
Preventing sepsis: for SCD
Continually assess for infection and monitor CBC with differential WBC count daily
Drug therapy
Hydration
O2 is given during crisis
Transfusion possible to help increase HbA levels
Most common type of inherited hemolytic anemia is the deficiency of the enzyme:
glucose-6-phosphate dehydrogenase (G6PD)
Define G6PD:
inherited as an X-linked recessive disorder with more severe expression in males and mild expression in carrier females
Affects 10% of Af. Americans and also may occur in Sephardic Jews, Greeks, Iranians, Chinese, Filipinos, and Indoesians
Cells with reduced G6PD do what
break more easily during exposure to some drugs
ex. aspirin
patient usually does not have manifestations until exposed to triggering agents or until severe infection
-after exposure, breakage begins and lasts 7-12 days. anemia and jaundice develop
Men in high risk of G6PD should do what?
be tested for this problem before being given drugs that can cause the hemolytic reaction
-Osmotic diuretics help prevent complications
Immunohemolytic anemia:
immune system products attack a person’s own RBCs for unknown reasons
2 types of immunohemolytic anemia:
- Warm antibody anemia: occurs with immunoglobulim G antibody excess, most active 98.6 F (37 C)
may be triggered by drugs, chemicals, or other autoimmune problems - Cold antibody: has complement protein fixation on immunoglobulin M, most active 86 F (30 C)
- occurs like Raynaud’s response
Anemias resulting from decreased production of RBCs:
Iron deficiency anemia: serum levels less than 10ng/mL
Vitamin B deficiency: glossitis - smooth beefy tongue
Folic Acid deficiency: due from malabsorption ex. Crohn’s
Aplastic therapy: failure of bone marrow to produce RBCs
Disorders of excess RBCs or Iron:
Polythemia Vera
Hereditary Hemochromatosis
Polythemia Vera Patho:
Hyperviscous
Increase hemoglobin levels to 18 g/dL, RBC count of 6 million/mm, hematocrit of 55% or greater
More than 90% of patients with PV show mutation of the
JAK2 kinase gene in the affected cells
Extreme hypercellularity of peripheral blood occurs in people with PV
Features of PV:
- the patient’s facial skin and mucous membranes have a dark, purple or cyanotic, flushed (plethoric) appearance with distended viens
- intense itching caused by diluted blood vessels and poor perfusion is common
- blood flow may be so slow that stasis occurs –> leads to thrombosis (clotting) within smaller vessels –> tissue hypoxia, anoxia and, later, to infartion and necrosis
Apheresis:
- the withdrawal of whole blood and removal of some of the patient’s blood component, in this case RBCs
- increasing hydration and promoting venous return help prevent clot formation - therapy for PV also includes the use of anticoagulants
- Aggressive IV chemotherapy is no longer recommended due to risks of getting leukemia
Hereditary hemochromatosis definition:
autosomal recessive disorder in which a mutation in both alleles of the HFE gene cause increased intestinal absorption of dietary iron
-excess iron is deposited in a variety of tissues and organs, including the liver, spleen, heart, joints, skin, and pancreas
Treatment: phlebotomy and removal of 500 mL of blood at a time, occurring as often as twice weekly at first, is performed to reduce the overall iron load of the blood
Myelodysplastic syndromes (MDS):
group of disorders caused by the formation of abnormal cells in the bone marrow
- decrease in all blood cell types
- Conditions include Anemia (most common), neutropenia (low WBC), and thrombocytopenia (low platelets)
- precancerous state but has cancer like features
Patients with MDS, patients are categorized into risk groups
based on the severity of panytopenia (low counts of all blood cell types), cytogenetic abnormalities, and numbers of blast cells (immature WBC) found in the bone marrow
-Exact cause is not clear
For low risk and intermediate 1 risk MDS, the antitumor immunomodulatory agent called what? And is approved for patients whose dysplastic cells have the chromosome abnormality of a deleted what?
lenalidomide (Revlimid)
5q
2 other agents approved for high risk intermediate 2-risk MDS are
Azacitidine (Vidaza)
Decitabine (Dacogen)
Platelet Disorders:
Autoimmune thrombocytopenic purpura (ITP)
Thrombotic thrombocytopenic purpura (TTP)
Thrombocytopenia:
Platelet numbers below that needed for blood clotting, may occur as a result of other conditions or treatments that suppress general bone marrow activity
Patho of ITP:
the number of circulating platelets is greatly reduced in ITP, even though platelet production is normal
-make an antibody against the surface of their own platelets, making destruction by macrophages easier
Assessment of ITP:
manifestations are first seen in the skin and mucous membranes; large ecchymoses (bruises) or a petechial rash on the arms, legs, upper chest, and neck; mucosal bleeding occurs easily
Interventions for ITP:
Risk for poor clotting and increased bleeding
- Drug therapy
- Platelet transfusions
- Maintaining a safe environment
- Surgical management
- Vaccinations against pneumococcal recommended
TTP definition:
- the patient has inappropriate clotting, yet the blood fails to clot when trauma occurs
- appears to be a small autoimmune reaction in small blood vessel cells that starts platelet aggregation and clotting there
- tissues become ischemic, leading to kidney failure, myocardial infarction, and stroke
-Drug therapy such as aspirin
Clotting factor disorders:
Hemophilia
Heparin Induced Thrombocytopenia
Hemophilia: definition and 2 forms
hereditary bleeding disorder
- Hemophilia A: classic, deficiency of factor of VIII and accounts for 80% of hemophilia cases
- Hemophilia B: Christmas disease, deficiency of factor IX
Assessment of Hemophilia:
- Excessive bleeding
- Joint and muscle hemorrhages
- A tendency to bruise easily
- Prolonged and potentially fatal hemorrhage after surgery
Heparim induced thrombocytopenia (HIT) definition and risk factors:
Serious immunity- mediated clotting disorder with an unexplained drop in platelet count after heparin treatment
Risk factors:
1. Duration of heparin use longer than 1 week
2.Exposure to unfractioned heparin
3. Postsurgical thromboprophylaxis
Treatment for HIT:
anitcoagulation therapy
Drug management such as argatroban (Argatroban), lepirudin (Refludan), and bivalirudin (Angiomax)
Transfusion therapy includes:
Pretransfusion responsibilities: use normal saline
Transfusion responsibilities: Remain with the patient for the first 15-30min
Types of Transfusions
Types of Transfusions:
RBC transfusions
Platelet transfusions
Plasma
Granulocyte (WBC)
Acute Transfusions Reactions:
Febrile transfusion reactions Hemolytic transfusion reactions Allergic transfusions Bacterial transfusion reactions Circulatory overload Transfusion associated graft-versus-host disease (TA-GVHD) Transfusion related acute lung injury (TRALI) Acute pain transfusion reaction
Febrile transfusion reactions:
occur most often in the patient with anti-WBC, antibodies, which can develop after multiple transfusions, WBC transfusions, and platelet transfusions
Hemolytic transfusion reactions are caused by
blood type or Rh incompatibility manifestations include: apprehension headache chest pain low back pain tachycardia tachypnea hypotension hemoglobinuria a sense of impeding doom
Allergic transfusions are most often seen in patients with
other allergies
Bacterial transfusion reactions
occur from infusion of contaminated blood products, especially contaminated with gram-negative organism
Circulatory overload:
can occur when a blood product is infused too quickly, especially in older adults
Transfusion associated graft-versus-host disease (TA-GVHD):
rare but life threatening problem that occurs more often in an immunosuppresed patient
Transfusion related acute lung injury (TRALI):
life threatening event that occurs most often when donor blood contains antibodies against the recipient’s neutrophil antigens, HLA, or both
Acute pain transfusion reaction (APTR):
recently identified but rare event that can occur during or shortly after transfusion of any blood product
-severe chest pain, back pain, joint pain, hypertension, and redness of the head and neck
Interventions for transfusion reactions
Stopping transfusion and removing blood tubing
-Do not flush contents of the blood transfusion tubing, which would allow more of the reaction causing blood to enter the patient
Autologous blood transfusions:
may be stored for 40 days
for patients with rare blood types, blood may be frozen for up to 10 years
The patient with Thrombocytopenia:
Avoid IM injections or venipunctures: use the smallest gauge needle if neccessary
Apply firm pressure to the needle stick site for 10 min or until site no longer oozes blood
Apply ice
Test presence of occult blood
Check IV sites every 2 hrs of bleeding
Avoid trauma to rectal tissues
Measure abdominal girth daily
Use an electric shaver
Avoid mouth trauma
Not to blow the nose or insert objects into the nose
Avoid contact sports
Wear shoes with firm soles with firm soles when ambulating
