Hematology Flashcards
Mean corpuscular volume (MCV)
= SIZE
Expression of the average volume and size of individual erythrocytes
-cytic = size
Can be microcytic, normocytic, or macrocytic
Microcytic
~ 80 fl
Normocytic
~ 80 - 100 fl
Macrocytic
~ 100 fl
Mean corpuscular hemoglobin concentration (MCHC)
= COLOR
Expression of the average hemoglobin (Hgb) concentration or proportion of each EBC occupied by Hgb as a percentage.
More accurate than mean corpuscular hemoglobin (MCH)
Can be Normochromic, hypochromic, or hyperchromic (although most text deny the existence of hyper= because it is impossible for a RBC to be too red
Normochromic
32-36%
Hypochromic
< 32%
Hyperchromic
> 36%
Mean corpuscular hemoglobin (MCH)
= WEIGHT
Expression of the average amount and weight of Hbg contained in a single erythrocyte; not as useful
Normal: 26-34 pg
Red cell distribution width (RCDW)
Red cell size variation (ie anisocytosis)
Differentiates b/w iron deficiency anemia (IDA), thalassemia, and anemia of chronic disease (ACD)
IDA: increased
Thalassemia: normal or slightly increased
ACD: normal
Reticulocyte count
Number of new, young RBCs in circulation
*immature cells
Expressed as a % (normal is 1-2%)
Index of bone marrow health and response to anemia: immune system is trying to fix anemia when it is pushing these out
Anemia d/t:
- Bone marrow failure
- Hemorrhage or hemolysis
Response to therapy
Anemias
Conditions caused by various disorders of the RBC count, quality of hemoglobin and/or volume of packed RBC
Anemias are classified according to RBC size (MCV) and hemoglobin concentration (MCHC)
Causes of microcytic/hypochromic anemia in children
IDA
thalassemia
lead poisoning
Causes of normocytic/normochromic anemia
ACD
acute blood loss
early IDA
Causes of macrocytic/normochromic anemia in adults
Vitamin B12 deficiency
folate deficiency
pernicious anemia
Iron Deficiency Anemia
Microcytic, hypochromic anemia d/t an overall deficiency of iron
Caused by decreased iron intake, increased needs, or slow GI blood loss
In infancy, iron deficiency is d/t
an inadequate intake of iron (low iron formula, solely breast fed) or micro hemorrhage from the gut d/t early intake of whole milk (before the age of 9 months - cannot break down the protein)
In toddlers, iron deficiency is often d/t
an increased reliance on whole milk at the expense of solid foods
In adolescence, iron deficiency is d/t
dieting practices that contribute to an inadequate intake of iron, specifically in girls after menarche
S/S Iron Deficiency Anemia
Severity depends on the degree of anemia!
- easy fatigability
- palpitations, SOB on exertion
- lethargy
- HAs
- Pica
- delated motor development
- pale, dry skin and mucous membranes
- tachycardia
- tachypnea
- postural hypotension in severe anemia
- brittle hair
- flat, brittle or spoon shaped nails
Labs/diagnostics for Iron Deficiency Anemia
CBC with retic count will show:
Low: Hgb and Hct MCV (microcytic) MCHC RBCs serum ferritin < 30 mcg.L serum iron
Increased:
red blood cell distribution width (RCDW)
total iron binding capacity
Reticulocyte count will be low in cases of inadequate iron intake or elevated in cases of blood loss
Management of Iron Deficiency Anemia
Goal: correct underlying cause
A medicinal iron supplement is require while the cause if being managed and should be continued until the resolution of the underlying process
Elemental iron treatment in Iron Deficiency Anemia
- Treat with elemental iron high dose 3-6 mg/kg/day in 1-3 doses until Hbg normalizes.
- Then replace iron stores with dosage of 2-3 mg/kg/day for 4 months (all RBCs have been replaced)
- Then continue with 1 mg/kg/day
Take with OJ to increase absorption
Thalassemia
A group of hereditary disorders that are characterized by an abnormal synthesis of alpha (four genes) and beta (two genes) goblin chains.
One ore ore of each gene can be missing.
Type is determined by which genes are missing (alpha vs. beta thalassemia)
Severity depends on number of genes affected – missing 3 or more, will likely need blood transfusions every month for rest of life
Causes/Incidence of Thalassemia
- Second most common cause of microcytic anemia
2. Autosomal recessive genetic disorder - both parents carry the gene
S/S of Thalassemia
Varies from asymptomatic to severe S/S of anema
- pale or bronze color to skin
- tachycardia
- tachypnea
- hepatosplenomegaly
- frontal bossing
Physical exam findings of Thalassemia
- Prenatal diagnosis
- Newborn screening **required
- Infancy: FTT/irritability, splenomegaly, pallor/severe anemia
- Older child: bony changes, splenomegaly, iron overload d/t multiple transfusions
Labs/diagnostic for Thalassemia
CBC: Decreased - HGB - MCV (microcytic anemia) - hypo chromic RBCs
Increased:
- Reticulocyte count
- ferritin
- total bilirubin
***Hemoglobin electrophoresis!! To make DIAGNOSIS
Management of Thalassemia
Refer to hematologist
Sickle Cell Anemia
An anemia in which abnormal hemoglobin (due to DNA point mutation) leads to CHRONIC HEMOLYTIC anemia and results in a variety of severe clinical consequences.
Peak incidence of infection is between 1-3 years of age
Causes/Incidence of Sickle Cell Anemia
Autosomal recessive disorder in which Hgb S develops instead of Hgb A. The patient is homozygous for Hgb S (Hgb SS)
Most prevalent in persons of African or African American ancestors; Hbg S gene is carried in 8% of AA: Incidence is 1:400
Patients who have heterozygous genotype (Hgb AS) are generally clinically asymptomatic (unless become hypoxic) but are carriers.
Symptoms of Sickle Cell Trait (Hgb AS)
Patients usually have no clinical symptoms.
May experience acute painful symptoms under extreme conditions such as exertion at high altitudes.
Symptoms of Sickle Cell Anemia (Hgb SS)
- Sudden, excruciating pain d/t a vast-occlusive crisis usually in the back, chest, abdomen, and long bones.
- clot – ischemia – PAIN – tissue damage
- low grade fever
- predisposing factors may be present (ie infection, physical or emotional stress, blood loss)
Physical exam findings of Sickle Cell Trait
These patients are clinically normal with no abnormal exam findings
Physical exam findings of Sickle Cell Anemia
- chronically ill in appearance
- jaundice
- retinopathy
- delayed puberty
- hepatosplenomegaly (spleen usually not palpable in the adult)
- enlarged heart with hyper dynamic precordium
- systolic murmur
- fatigue
- tendency toward more frequent infections (which also aggravates crisis)
Labs/diagnostics for Sickle Cell Anemia
- hematocrit 20-30%
- irreversibly sickled cells on peripheral blood swear (5-50% total) ***
- nucleated RBCs (immature red cells)
- increased reticuloycytosis (10-25%; immature red cells without nuclei)
- target cells (abnormal RBCs)
- Howell-Jolly bodies (asplenic conditions)
- increased WBCs characteristically elevated to 12,000-15,000 per microliter
- indirect bilirubin elevated
- platelets may be elevated (>400,000) = thicker blood
**Hemoglobin electrophoresis to MAKE DIAGNOSIS
Children with sickle cell trait may have episodes of gross hematuria and inability to concentrate the urine d/t renal tubular damage
Management of Sickle Cell Anemia
- Collaboration with a hematologist!!
- Maintained chronically on folic acid supplementation.
- Cornerstone of therapy is to prevent episodes and to provide support during the crisis episode
- Keep adequately hydrated
- Ensure adequate oxygenation
- Analgesics for pain control
- Antibiotics for associated infection
- Transfusions and/or exchange transfusions for intractable crisis and as a preventative measure for clients undergoing anesthesia - Hydroxyurea 35 mg/kg/day to stimulate fetal hemoglobin (Hgb F), which does not sickle
- Immunize with Pneumovax (PS-23) and confirm hepatitis B immunity
- Provide or refer for genetic counseling.
Hemophilia A (X-linked Recessive)
Deficiency of factor VIII (8)
Occurs in 1:7,000 males (males only)
Frequency of female carriers is about 1:3,500:
- 25% risk of having an affected son with each pregnancy
- 25% risk of having a carrier daughter
- 25% chance of having a healthy, non-carrier daughter or son
Severe form occurs in about 48% of cases
Typical findings of Hemophilia A (X-linked Recessive)
Phenotypically normal at birth
Bleeding tendency: ranges from spontaneous bleeding to bleeding after trauma
*Find often during circumsicion, but can also screen for in prenatal screen/do embryo selection
Treatment of Hemophilia A (X-linked Recessive)
Infusions of recombinant factor prophylactically or only when a bleed occurs
Lead Poisoning
A chronic disease that results from the toxic accusation of lead int he body that leads to iron deficiency anemia (IDA).
Centers for Disease Control and Prevention (CDC) definition of lead poisoning is a level > 5 mcg/dl.
- Can occur via ingestion or inhalation
- Highest prevalence is among poor, inner-city children, and those living in old housing
Common sources of Lead Poisoning
- Paint and paint dust (houses prior to 1978; mandates laws require lead free paint!)
- Contaminated soil
- Gasoline emissions
- Food and drinking water
- Mexican Americans, Asian, Indian, or other ethnic folk remedies
S/S of Lead Poisoning
- vague: GI symptoms
- severe: lethargy, difficulty walking, neuropathies
- HA
- Burtonian lines: bluish discoloration of gingival border !! Blue line on the gum line d/t oxidization of the lead
- ataxia
- papilledema
General Assessment for Lead Poisoning
- Medical and developmental history (mouthing and pica history)
- Environmental history
- Nutritional history
- Physical exam
Environmental history for Lead Poisoning
- paint and soil exposure
- residence: year <1978 and condition
- outside play
- control of dust and dirt
- family members’ behaviors, occupations
- family members’ hobbies (fishing, ceramic work, stain glass, and hunting)
- exposure to imported food, folk remedies, pottery, metal vessels
Nutritional history for Lead Poisoning
- diet history
- evaluate the child’s iron status by using the appropriate lab tests
- ask about history of food stamps or participation in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)
Venous Blood Level Concentrations for Lead Poisoning Classification
Class I: Level <10 mcg/dl
Class IIA: Level 10-14 mcg/dl – refer to hematologist
Class IIB: Level 15019 mcg/dl
Class III: Level 20-44 mcg/dl
For all the above, try to fix the exposure (minimize or eliminate source)
Class IV: Level 45-69 mcg/dl – recommended chelation therapy***
Class V: Level > 70 mcg/dl – hospitalize for chelation, hydration, and close observation
Management of Lead Poisoning
Observe for hemoglobinopathies, impaired renal function, or Vitamin D deficiencies
Leukemias
1 childhood cancer
A group of malignant hematological diseases in which normal bone marrow elements are replaced by abnormal, poorly differentiated lymphocytes known as blast cells
Acute lymphocytic leukemia (ALL)
Accounts for ~ is 75% of cases
Peak incidence around 4 years of age
Occurs more frequently in boys than girls
More common among Caucasian children
Easiest to treat and high survival rate
Acute myelogenous leukemia (AML)
Accounts for ~ 20% of all leukemia
Occurs primarily in infants and older children
Hard to treat, lower success rates, increased secondary malignancies
S/S of Leukemias
Anemia Pale Listless Irritable Chronically tired History of repeated infections Bleeding such as epistaxis, petechia, and hematoma Lymphadenopathy and hepatosplenomegaly Bone and joint pain
Labs/diagnostics for Leukemia
- CBC with differential WBC, platelet, and reticulocyte counts
- thrombocytopenia is present is up to 85% of cases, and anemia is usually present - Peripheral smear may demonstrate malignant cells (blasts).
- Bone marrow will show the poorly differentiated blast cells that have been replacing the healthy bone marrow tissue.
**Bone marrow aspiration + biopsy to DIAGNOSE.
Management of leukemia
- Referral to an oncologist
2. Family support
