Lecture 9 - Pediatric Cases Flashcards
When does the physiologic nadir (low) for Hb occur in infants?*
At approximately 2 months of age
What effect does anemia have on the Hb O2 dissociation curve?
Concentration of 2,3-DPG increases within the RBC —> oxygen dissociation curve shifts to the right —> affinity of Hb for oxygen is reduced in tissues needing to be oxygenated
Anemia also results in increased CO (HR goes up and flow murmur may be heard)
What are the pertinent components of a history to obtain when evaluating a person with suspected anemia?
Hx: race and ethnicity, diet, meds, chronic illness, recent infections, travel, exposure to sick contacts
FHx looking for anemia, splenomegaly, jaundice, early stage onset of gallstone
What are the signs and sx often seen in pts with anemia?
Sleepiness, irritability, decreased exercise tolerance, pale appearance, blood stool/urine, LAD, fever, viral sx, pain, menses (flow/length), SOB cough
The slower the anemia develops the better the body can what?
Compensate
Rapidly developing anemia usually results in more dramatic sx
Look at
Anemia flow chart
Anemia is the result of one or more of the following
Decreased RBC production (in bone marrow) Increased RBC destruction (hemolysis) Blood loss (acute or chronic)
Describe intravascular hemolysis
Results in anemia, hemoglobinuria, hemoglobinemia, hemosiderinuria, jaundice
Mechanical, auto immune (complement fixation), intracellular parasites, toxins/drugs
Describe extravascular hemolysis
Results in anemia, jaundice, splenomegaly and sometimes hepatomegaly
Occurs in the reticuloendothelial system
Macrophages phagocytize RBCs as the result of abnormalities in RBC membrane/deformability
A low or low-normal number of reticulocytes in a pt with anemia is indicative of what?
An inadequate bone marrow response
Relative bone marrow failure
Ineffective erythropoiesis
An increased number of reticulocytes is a normal bone marrow response to what?
Anemia (its trying to keep up, the problem is NOT with the bone marrow)
Ongoing RBC destruction (hemolysis), sequestration, blood loss
What is Diamond-Blackfan syndrome/anemia?
Congenital pure red cell aplasia that almost always presents in infancy
Increased apoptosis in erythroid precursors
Macrocytic with low/inadequate reticulocyte count
What is Fanconi anemia?*
Most common inherited form of aplastic anemia (bone marrow failure syndrome with all cell lines affected)
Macrocytic anemia with low/inadequate reticulocyte count
Leukopenia and thrombocytopenia are also present
GU and skeletal abnormalities
Due to genetic mutations; increased chromosome fragility
Increased apoptosis in the bone marrow
Progresses to pancytopenia
Autosomal recessive, May be up to 10 years old before it presents
Describe iron deficiency anemia
Commonly caused by a dietary deficiency of iron in pediatric patients
Common
Microcytic, hypochromic anemia with high RDW in infants and toddlers
Target cells on peripheral smears
Iron, ferritin and iron saturation are all low
Transferrin level is elevated
Pale child, big cow’s milk drink (suspect IDA)
What is the Mentzer index?
Useful in distinguishing IDA from beta thalassemia minor/trait in pediatric patients with mild microcytic anemia
MCV/RBC
What does a Mentzer index of >13 mean?
IDA is more likely
What does a Mentzer index of <13 mean?
Thalassemia trait is more likely
What does a Mentzer index of =13 mean?
Indeterminate
How do you calculate the absolute neutrophil count (ANC)?
((%neutrophils + %bands) x WBC) / 100
Mild neutropenia = 1000-1500
Moderate neutropenia = 500-100
Severe neutropenia = <500
What class of drugs are most commonly associated with neutropenia?
Chemotherapeutics are most commonly associated with a lowered ANC
What is Kostmann syndrome?
Severe congenital neutropenia (ANC <200)
Autosomal recessive
Life threatening pyogenes infections early in life
Impaired myeloid differentiation caused by maturational arrest of neutrophil precursors
Increased risk of leukemia (AML)
What is cyclic neutropenia?
Cyclic fever, oral ulcers, gingivitis, periodontal disease, recurrent bacterial infections
Stem cell regulatory defect resulting in defective maturation
ANC <200 for 3-7 days every 15-35 days
Autosomal dominant or sporadic
No increased risk of malignancy
What is Schwachman-Diamond syndrome?
Triad of neutropenia, exocrine pancreas insufficiency, and skeletal abnormalities
Defects in neutrophil mobility, migration, and chemotaxis in addition to neutropenia
Autosomal recessive
Increased risk for myelodysplastic syndrome or leukemia