Hematology Flashcards
Definition of anemia
Reduction in RBC mass or blood Hb conc 2 standard deviations below normal for age and sex
<11 for all kids 6 mos-5 yrs
Reasons for normocytic, normochromic anemia
Anemia of chronic disease
Reasons for microcytic, hypochromic anemia
Iron deficiency, thalassemia, lead intoxication
Reasons for macrocytic anemia
Vitamin B12 and folate deficiency
Acute signs and sxs of anemia
Lethargy, tachycardia and pallor
Infants might be irritable and have poor oral intake
Types of bone marrow failure
Fanconi anemia and acquired aplastic anemia
What is Fanconi anemia?
Inherited bone marrow failure syndrome (autosomal recessive) due to defective DNA repair
Usually first 5 yrs of life
Manifestation of Fanconi anemia
Progressive pancytopenia
May have abnormal pigmentation of the skin, short stature, skeletal malformations
Increased malignancies
Lab findings of fanconi anemia
Thrombocytopenia or leukopenia (usually seen before the anemia)
Severe aplastic anemia
Bone marrow hypoplasia or aplasia
What is fanconis often misdiagnosed as?
ITP
Treatment for fanconis
Supportive
HSCT
Prognosis of fanconis anemia
Pts at high risk of developing myelodysplastic syndrome or AML
Many die of bleeding, infection or malignancy in adolescence
What is acquired aplastic anemia?
Peripheral pancytopenia with a hypocellular bone marrow (looks similar to fanconis)
Mostly idiopathic
Sxs of acquired aplastic anemia
Weakness, fatigue, pallor (anemia)
Frequent infections (leukopenia)
Purpura, petechiae and bleeding (thrombocytopenia)
Lab findings in acquired aplastic anemia
Anemia usually normocytic
Low WBC with neutropenia
Thrombocytopenia
Low retic count because of bone marrow failure
Leading causes of death in acquired aplastic anemia
Overwhelming infection and severe hemorrhage
Tx of acquired aplastic anemia
Supportive care, referral
Abx for infection
Transfusions
HSCT blah blah
What is the most common nutritional deficiency in kids?
Iron deficiency anemia
When is iron deficiency anemia more prevalent?
African Americans and Hispanic children
When is screening for anemia performed?
At 12 mos (determine hb conc and assess risk factors)
Risks of iron deficiency anemia
Low status
Premature/low birth weight
Lead exposure
Exclusive breast feeding beyong 4 mos without iron supplements
Moving to milk or food without iron
Feeding problems, poor growth, inadequate nutrition
Lab findings in iron deficiency anemia
Microcytic, hypochromic anemia
Hb < 11
Ferritin < 12
Usually RDW high
Tx for iron deficiency anemia
Hb of 10-11 (close follow)
IDA- iron 6 mg/kg/d with 3 divided daily doses
What causes B12 deficiency?
Intestinal malabsorption (Crohns, ulcerative colitis, Celiac) Dietary insufficiency (vegans)
What causes folate deficiency?
Increased folate requirements (rapid growth, chronic hemolytic anemia)
Malabsorptive syndromes
Inadequate dietary intake (rare)
Meds
Signs of macrocytic anemia
Pallor
Glossitis
B12- neurologic sxs in older children
Lab findings of macrocytic anemia
Elevated MCH and MCV
Neutrophils large and have hypersegmented nuclei
Macro-ovalocytes
Elevated methylmalonic acid in B12
Elevated homocysteine with B12 and folate
Tx of macrocytic anemia
Supplementation
Must treat the B12 deficiency to treat neurologic probs
*tx with folate will fix anemia picture in B12
Types of congenital hemolytic anemias
Hereditary spherocytosis
Thalassemia
Sickle cell
G6PD
Hereditary spherocytosis
Red cell membrane defect Hemolytic anemia (jaundice, splenomegaly, gallstones) Spherocytes Increased osmotic fragility Maybe splenectomy
Thalassemia
Alpha or beta (severity based on gene deletions)
Hb electrophoresis for diagnosis
Support with RBC transfusion (iron monitoring + chelation, splenectomy, HSCT)
Most common sign of sickle cell disease
Vaso-occlusion (pain)
Tx of sickle cell disease
Hydroxyurea
Tx for painful vaso-occlusive episodes
Stem cell transplant
What is G6PD deficiency?
Red cell enzyme defect that causes hemolytic anemia
Highest among African, Mediterranean and Asian ancestry
Manifestations of G6PD deficiency
Neonatal jaundice, hyperbilirubinemia
Episodic hemolysis due to oxidant stress of infection or certain drugs/foods- pallor, jaundice, hemoglobinuria
Peripheral smear on G6PD deficiency
Bite like deformities and Heinz bodies
When might you suspect lead poisoning?
Older homes with lead paint
Manifestations of lead poisoning
Mild, hemolytic and normocytic anemia
Basophilic stippling on peripheral smear
Tx for lead poisoning
Chelation
Types of polycythemia
Primary and secondary
Familial polycythemia (congenital erythrocytosis)
Only RBCs affected
Hb may be as high as 27
Plethora (ruddy complexion) and splenomegaly maybe
HA and lethargy
Tx of familial polycythemia
Phlebotomy
Secondary polycythemia
In response to hypoxemia (cyanotic congenital heart disease like ToF or TGA or chronic pulm disease)
Tx: correction of disorder and maybe phlebotomy
Initial screening tests for bleeding disorder
CBC
Peripheral smear
Pt/INR, aPTT
Maybe bleeding time
Platelet count testing for bleeding disorders
Normal is 150,000-400,000
Risk of bleeding less than 20,000
PT test
Measures extrinsic and common pathways (I, II, V, VII, Xa and tissue factor)- 7 and TF specific
PTT/aPTT
Measures intrinsic and common pathways (I, II, V, VIII, IX, X, XI, XII)- 8, 9, 11, 12 specific
INR testing
More accurate reflection of PT
Used to monitor Warfarin tx
Bleeding time test
Screen test for platelet dysfunction
Prolonged in platelet disorders (von Willebrand) and severe thrombocytopenia
What is the most common bleeding disorder of childhood?
Idiopathic thrombocytopenia purpura
When does ITP occur?
Often after infection with viruses (immune-mediated)
Why does ITP occur?
Immune mediated attack against its own platelets
Manifestations of ITP
Multiple petechiae
Ecchymosis
Epistaxis
Lab findings of ITP
Thrombocytopenia
Normal WBC
Normal Hb
PT and aPTT normal
How do you diagnose ITP?
Diagnosis of exclusion
Tx of ITP
Observe when asymptomatic Avoid meds that compromise platelets (ASA, NSAIDs) Prednisone IVIG Splenectomy
Inherited bleeding disorders
von Willebrand disease
Hemophilia
What is the most common inherited bleeding disorder?
von Willebrand disease
Genetic problem of von Willebrand disease
Decrease in level or impairment in action of vWF
What is vWF?
A protein that binds to factor VIII and is a cofactor for platelet adhesion to endothelium
Presentation of von willebrand disease
Prolonged bleeding from mucosal surfaces (epistaxis, menorrhagia, GI)
Easy bruising
Lab findings of von Willebrand disease
Normal PT Prolonged or normal aPTT Normal or decreased factor VIII Normal or decreased vWF Prolonged bleeding time (differentiate from hemophilia)
Treatment of von willebrand disease
Desmopression (causes release of vwf and factor VIII from endothelial stores)
vWF replacement therapy
Types of hemophilia
A- factor 8 deficiency (most common)
B- factor 9 deficiency (christmas disease)
male most common
Presentation of hemophilia
Bleeding from impaired hemostasis Common sites into joints and muscles Spontaneous hemarthrosis (into joint)- severe disease
Presentation of mild hemophilia
Bleed in response to injury/trauma or surgery
May not be clinically apparent until later in life
Presentation of severe hemophilia
Severe, spontaneous bleeding
Earlier age of first episode
Lab findings of hemophilia
Normal platelet count, PT and bleeding time
Prolonged aPTT
Normal vWF
Tx of hemophilia
Desmopression: hemophilia A
Factor replacement: both (to achieve sufficient hemostasis)
What is DIC?
Hemorrhage and microvascular thrombosis (triggered by sepsis, trauma/tissue injury, malignancies)
Signs and sxs of DIC
End-organ dysfunction (shock)
Persistent oozing from needle punctures or other invasive procedures (common)
Hematuria, melena, purpura, petechiae
Purpura fulminans, major vessel thrombosis
Lab findings of DIC
*elevated D dimer and fibrin degradation products
Decreased platelets
Prolonged aPTT and PT
Decreased fibrinogen
Tx of DIC
ID and treat triggering event
Replacement therapy for consumptive coagulopathy
Anticoagulant therapy
What is synthesized in the liver?
Prothrombin, fibrinogen
Factors V, VII, IX, X, XII and XIII
Which are the vitamin K dependent factors?
II, VII, IX and X
Lab findings in liver disease
Platelet count normal in vitamin K deficiency and maybe low in liver disease
Prolonged PT, aPTT
Tx of liver disease
Treat underlying condition
Vitamin K at birth
Inherited thrombotic disorders
Protein C/S deficiency
Antithrombin deficiency
Factor V leiden mutation
What is Protein C deficiency?
Protein C inactivated factors V and VIII
May develop warfarin-induced skin necrosis
What is protein S deficiency?
Protein S is a cofactor for protein C (facilitates action of activated protein C)
What is factor V leiden mutation?
Point mutation
Factor V polymorphism is resistant to inactivation by activated protein C
VTE and factor V leiden mutation
Risk of VTE is increased
Among heterozygotes taking oral contraceptives
Among homozygotes much higher
Antithrombin deficiency
It is a major physiologic inhibitor of thrombin
Presentation of antithrombin deficiency
VTE
Tx for bleeding disorders
Anticoagulant prophylaxis
UFH, LMWH, warfarin
First VTE for at least 3 mos (may need long term)
What is Henoch-Schonlein Purpura?
Most common type of small vessel vasculitis
Mostly boys (2-7)
In spring and fall
URI often precedes diagnosis (like ITP)
Pathophysiology of HSP
Deposition of IgA immune complexes in small vessels of skin, GI tract and kidneys
Presentation of HSP
Palpable purpura
Arthritis/arthralgias
Abdominal pain
Renal disease
Lab findings of HSP
Usually normal platelet count
Antistreptolysin O titer often elevated
Hemoccult may be positive
Hematuria (sometimes proteinuria)
Tx of HSP
Supportive, good prognosis
