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
Children with fanconi anemia have an increased risk of developing what?
AML, brain tumors, Wilms tumor
What is leukocyte adhesion deficiency?
Very rare
Results in delayed separation of umbilical cord stump (>3 weeks), recurrent and severe bacterial and fungal infections without pus formation, poor wound healing
Neutrophils have diminished adhesion to surfaces
Autosomal recessive
No known associated risk of malignancy
What is hyper immunoglobulin E syndrome (Job syndrome)?
Triad of severe eczema, recurrent bacterial infections (usually staph) of skin, recurrent pulmonary infections (bacterial, fungal)
Defect in chemotaxis of neutrophils, increased IgE, eosinophilia
Very rare, sporadic, autosomal dominant
Increased risk of HL
What is Chediak Higashi syndrome?
Partial oculocutaenous albinism, neuropathies, recurrent pyogenic infections
Defects in chemotaxis and degranulation, ineffective granulopoiesis
Very rare autosomal recessive
Usually fatal by 20 years of age
No known link to malignancy
What is chronic granulomatous disease?
Recurrent purulent infections with fungal or bacterial catalase positive organisms
Usually starts in infancy
Chronic inflammatory granulomas
Defect in oxidative metabolism, absent generation of superoxide
Primarily X linked recessive
1:250,000
No known increased risk of malignancy
Describe parvovirus B19 infections (Fifths disease)
Commonly seen viral illness with associated characteristics viral exanthem occurring 1-2 weeks after infection with the virus (bright red cheeks followed by a diffuse, lacy, erythematous rash)
Commonly results in anemia, can result in neutropenia/thrombocytopenia
Most adults have had this virus and are somewhat immune
Has been associated with spontaneous abortion in non immune women
What immune deficiency is associated with DiGeorge syndrome?
Associated with absent thymus resulting in T cell immunodeficiency
What is the #1 cause of death due to illness in the US among children?*
Brain cancer
Followed by leukemias
What is the overall #1 cause of death in children?
Unintentional injuries (accidents)
What is the most common malignancy between ages 15-19?
Hodgkin lymphoma
HHV-6, cytomegalovirus, and EBV have been implicated in the occurrence of HL
What is the pathognomonic feature of HL?
Reed Sternberg cells (owl eyes)
What are the B signs associated with HL?
Unexplained fever of 39C (102.2 F)
Weight loss >10% total body weight over 6 months
Drenching night sweats
What are the indications for a CXR in a patient with LAD?
Any pt with persistent unexplained LAD unassociated with an obvious underlying inflammatory or infectious process should undergo a CXR to rule out a mediastinal mass (lymphoma loves the mediastinum)
Any pt with persistent LAD and accompanying respiratory sx (cough, SOB, chest pain) should have a CXR
What is the most common type of lymphoma in children and adolescents?
Non Hodgkin lymphoma
What is Wiscott-Aldrich syndrome?
X linked recessive
Classic triad of recurrent sino pulmonary and ear infections, severe atopic dermatitis, bleeding secondary to significant thrombocytopenia
Predisposes to development of lymphoma, especially B cell lymphoma (NHL)
What are the 3 types of Burkitt lymphoma?
Sporadic
Endemic type
Immunodeficiency related
Describe sporadic type Burkitt lymphoma
Abdominal disease, sometimes associated with EBV
Most often in Africa but can occur in other geographic places
Describe endemic type Burkitt lymphoma
Head and neck disease, most often seen in Africa near the equator
Associated with EBV and malaria
Describe immunodeficiency related Burkitt lymphoma
Associated with the use of immunosuppressive drugs
What condition accounts for the greatest percentage of childhood malignancies?
Leukemias
Acute leukemias account for 97% of all childhood leukemias
What genetic trisomy is associated with both AML and ALL?
Trisomy 21 (Down syndrome)
Clinically significant bleeding is possible with a platelet count of what value?
<20 x 10^3/uL
Life threatening hemorrhage is possible with a platelet count of what value?
<10 x 10^3/uL
What is the most common cause of low platelets in kids?
ITP
What clinical findings are consistent with thrombocytopenia?
Petechiae, purpura, gingival bleeding, epistaxis, menorrhagia, GI bleeding, hematuria, CNS hemorrhage, ecchymosis/bruises (excessive in unusual locations, easy bruising)
Which conditions are associated with decreased platelet production?
Nutritional deficiencies (B12, folate, iron) Bone marrow failure or infiltration (aplastic anemia, leukemia, lymphoma) Genetic disorders (Wiscott Aldrich syndrome, Fanconi anemia, Schwachman Diamond syndrome, thrombocytopenia-absent radius syndrome (TAR)
Which conditions are associated with increased platelet destruction/consumption?
ITP, HUS, TTP, Kasabach Merritt phenomena
Describe immune thrombocytopenic purpura*
Fairly common (5/100,000 annually)
Kids usually feel okay
Anti platelet Abs
50% follows a viral infection by 1-3 weeks
Plt count usually <20,000 with other cell lines being normal
If other cell lines are affected must consider bone marrow aspirate (especially if steroid therapy is being considered)
PT/PTT normal
Tx: usually will self resolve with supportive care, prednisone is used when severe, may become chronic
What is Kasabach-Merritt phenomenon?*
Thrombocytopenia and hypo-fibrinogenemia associated with giant hemangioma and associated intravascular coagulation
Rare
What are red flag in pts with thrombocytopenia?
Any evidence of pancytopenia
Raised LDH (elevated in cancer)
Associated new renal impairment
What is the criteria for diagnosing ITP?
Anti platelet Abs present
Normal RBCs, PT/INR, PTT, fibrinogen, fibrin monomers, fibrin degradation, D dimers
Therapy = steroids and IVIG
Describe acute ITP
Peak incidence of 2-6 years
Antecedent infection common 1-3 weeks before
Abrupt onset of bleeding
Platelet count <20,000
Eosinophilia/lymphocytosis is common
Duration = 2-6 weeks, rarely longer
Spontaneous remission occurs in 80% of cases
Describe chronic ITP
Peak age 20-40 years 3:1 female:male Antecedent infection unusual Insidious onset of bleeding Platelet count 30-80,000 Eosinophilia/lymphocytosis rare Duration = months or years Spontaneous remission uncommon
Describe hemolytic uremic syndrome
Presents after acute gastroenteritis (within the last 2 weeks) as a classic triad of microangiopathic hemolytic anemia, thrombocytopenia, acute renal damage/failure
Most cases are caused by E. Coli O157:H7 (produces shiga toxin)
Prognosis depends on the amount of renal damage and blood in the urine will always be present (if protein is present prognosis is worse)
What is the usual presentation and lab findings in a child with ITP?
Overall the kids feel pretty well
History of viral infection in the last 1-3 weeks
Clinical findings consistent with low platelets
