Pediatric Anemia (Newman) Flashcards
Understand that “normal” values for hemoglobin and hematocrit in the pediatric population vary with age.
hemoglobin and hematocrit vary with age.
Describe the effect anemia has on the hemoglobin oxygen dissociation curve.
erythrocytic 2,3-diphosphoglycerate (2,3-DPG) unloads O2 from Hgb into tissues.
an increase in 2,3-DPG decreases oxygen affinity and vice versa.
In anemia, 2,3-diphosphoglycerate (2,3-DPG) increases within the RBC–> O2 dissociation curve “shifts to the right”. Affinity of Hb for oxygen is reduced in tissues needing to be oxygenated (Hgb releases its O2 to the tissues/organs that need it).
Obtain the pertinent components of a history when evaluating a person with anemia.
The most important part of an anemia workup is the history and physical.
- Historical facts important to get in someone with anemia:
- age
- children at different developmental stages have different habits (drink a lot of milk, put things in mouths (lead), eat dirt)
- race and ethinicity (country or region of origin)
- thalassemias
- sex
- menstruation
- diet
- diet poor; iron, B12, folate deficiencies
- medications
- chronic diseases
- anemia of chronic disease
- infections
- travel
- exposures
- age
- Family HX: anemia, splenomegaly, jaundice (hemolytic process), early-age onset of gallstones (hemolytic process)
Be familiar with the clinical signs and symptoms often seen in patients with anemia.
- Clinical Features (often not seen until Hgb is below 7-8g/dL) :
- Pallor (tongue, nail beds, palms, conjunctiva inside lower eyelid, mucosal surfaces)
- sleepiness
- Irritability
- decreased exercise tolerance
- flow murmur (due to increased CO to deliver same amount of O2 to organs)
- increased CO can cause flow murmur
- As anemia becomes more severe:
- weakness
- tachypnea
- SOB on exertion (any exertion)
- tachycardia
- cardiac dilation/cardiomyopathy
- high output heart failure
- the more slowly the anemia develops, the better the body can compensate
Classify anemias using RBC indices: aka MCV, MCHC, RDW
A. MCV (microcytic, normocytic, macrocytic)
- MCV (mean corpuscular volume) RBC SIZE
- measured directly by automated blood cell counters
- represents the mean value of the volume of individual RBC’s in the sample
- fL=femtoliter=10-15 liter=one quadrillionth liter
- Anemia classifications based on MCV:
- Microcytic ( < 2.5th percentile for age, race, and sex)
- Normocytic (between 2.5th-97.5th percentile for age, race, and sex)
- Macrocytic (MCV > 97.5th percentile for age, race, and sex)
Classify anemias using RBC indicies: aka MCV, MCHC, RDW
B. MCHC (hypochromic, normochromic, hyperchromic)
- MCHC (mean corpuscular hemoglobin concentration) RBC COLOR
- A calculated index (MCHC=Hgb/Hct)
- Grams of Hgb per 100 mL of RBC’s
- Anemia classifications based on MCHC:
- Hypochromic (< 32 g/dL)
- Normochromic (33-34 g/dL)
- Hyperchromic (>35 g/dL)
Classify anemias using RBC indicies: aka MCV, MCHC, RDW
C. RDW
- RDW (red cell distribution width)
- quantitiative measure of the variability of RBC sizes in sample (anisocytosis)
- percent (if all RBC’s were EXACTLY the same size, the RDW=0%)
Explain what a peripheral smear shows and also possible findings.
Provides information about RBC and WBC morphology, platelet “clumping”, and hemolysis.
- Vocab/Possible findings:
- Anisocytosis=different sizes
- Poikilocytosis=different shapes
- Schistocytosis= fragments of RBC’s (often secondary to hemolysis, microangiopathies)
- The peripheral smear may reveal changes in RBC morphology. Helpful in further narrowing the differential diagnosis.
Overall, anemia is a result of which conditions?
- Decreased RBC production (in bone marrow)
- Increased destruciton of RBC’s
- Blood loss
How/why does decreased RBC production cause anemia?
- Decreased RBC production (in bone marrow)
- ineffective erythropoeisis
- complete or relative failure of erythropoeisis
How/why does increased RBC destruction cause anemia?
- Increased RBC destruction
- Hemolysis
- intravascular causes:
- mechanical injury
- complement fixation (autoimmune illness)
- intracellular paracites
- toxins/drugs
- Principle features:
- anemia
- hemoglobinuria*
- hemoglobinemia*
- hemosiderinuria*
- jaundice
- * all a result of hemoglobin being released directly into the circulation, not seen in extravascular hemolysis
- extravascular causes
- macrophages in reticuloendothelial system (mainly the liver, spleen, bone marrow, and lymph nodes) phagocytize rbc’s as a result of abnormalities of RBC membrane/deformability of rbc’s)
- principle features:
- splenomegaly (can see sequestration as in sickle cell, hereditary spherocytosis, etc)
- anemia
- jaundice
- intravascular causes:
- Hemolysis
How/why does increased bleeding cause anemia?
- Acute
- normochromic, normocytic
- Chonic
- hypochromic microcytic (iron deficiency)
Discuss the usefulness of knowing the reticulocyte count of a patient with anemia.
Always follow up an anemia CBC with a reticulocyte count. Tells you whether or not the underlying problem is with the bone marrow.
- Low or low-normal number of reticulocytes in a patient with anemia is indicative of inadequate bone marrow response.
- relative bone marrow failure
- ineffective erythropoeisis (not enough building blocks)
- Anemia with a HIGH reticulocyte count= bone marrow is responding appropriately (it’s trying to keep up!)
- ongoing RBC destruction (hemolysis)
- sequestration (splenomegaly)
- Loss (bleeding)
REMEMBER: A low-normal reticulocyte count is an inadequate bone marrow response in the face of significant anemia.
Identify Diamond-Blackfan syndrome as a congenital pure red cell aplasia.
Pt presentation=macrocytic anemia with low reticulocyte count.
Diamond-Blackfan syndrome= congenital pure RBC aplasia resulting from increased apoptosis in erythroid precursors (30% have other abnormalities, average age of diagnosis is 3 months old. ) Is the “gold-standard” example of congenital RBC aplasia.
Identify Fanconi anemia as the most common form of inherited aplastic anemia.
Pt presentation= macrocytic anemia and reticulocytopenia, thrombocytopenia, and leukopenia.
- The most common inherited form of aplastic anemia.
- increased suceptibility of progenitor cells in bone marrow leads to increased apoptosis.
- progresses to pancytopenia (may not see symptoms until around 10 years old)
Anemia workup in children.
