Hematology Flashcards
What is the most common primary childhood CNS tumors?
astrocytoma - develop from astrocytes
What are the symptoms of astrocytoma?
most patients have symptoms consistent wit increased intracranial pressure (morning headaches
-often benign
What are the symptoms when the astrocytoma is located in the cerebellum?
weakness, tremor, and ataxia
What are the symptoms when the astrocytoma is located in the visual pathway?
visual loss, proptosis, or nystagmus
What are the symptoms when the astrocytoma is located in the spinal cord?
pain, weakness, and gait disturbances
How is the dx of astrocytoma made?
diagnosis is based on MRI and histologic evaluation of biopsy
What is the tx of astrocytoma?
combination of surgical resection, radial therapy, and chemotherapy
-have the best posterior fossa tumor prognosis, with a 90% five-year survival rate
What is the most common malignant posterior fossa tumor in children?
medulloblastoma and represents about 20% of all pediatric CNS cancers
What are the characteristics of medulloblastoma?
- metastasize through CSF
- it has a bimodal peak at age 3 to 4 years and at age 8 to 10 years but can occur throughout childhood
What is the presentation with a medulloblastoma?
most commonly with vomiting, headache, nausea, visual changes (double vision), and unsteady walking or clumsiness
How is the dx of medulloblastoma made?
diagnosis is based on MRI and histologic evaluation of biopsy
What is the tx of medulloblastoma?
combination of surgery, radiation therapy, and chemotherapy
-the long-term survival with treatment is about 70%
What is the 3rd most common CNS tumor in children?
ependymoma
-after astrocytomas and medulloblastomas, representing 10% of pediatric brain tumors
What is the mean age at diagnosis for ependymoma?
6 years, about 30% of ependymomas occur in children <3 years
What are the initial symptoms of ependymoma?
typically related to increased intracranial pressure
- infants may present with developmental delay and irritability
- changes in mood, personality, or concentration may occur
- seizures, balance and gait disturbances, or symptoms of spinal cord compression (back pain, loss of bladder and bowel control) may occur
How is the dx of ependymoma made?
diagnosis is based on MRI and histologic evaluation of biopsy
What is the tx of ependymoma?
surgical resection, usually followed by radiation therapy
- sometimes chemotherapy
- the survival rate depends on age and on how much of the tumor can be removed
- total or near total removal: 51 to 80% survival
- less than 90% removal: 0 to 26% survival
What is a retinoblastoma?
- malignancy of the retina of the eye
- often presents in children less than 3 year of age
- physical exam - leukocoria (absence of red-light reflex)
What is the tx of a retinoblastoma?
surgical enucleation of the eye, chemotherapy
What is hemophilia?
a hereditary bleeding disorder caused by a deficiency in one of two blood clotting factors
What are the two forms of hemophilia?
- factor VIII in hemophilia A which accounts for 80% of all cases
- factor IX in hemophilia B (Christmas disease)
- *Remember: Hemophilia A = “Aight” and B comes after A which is factor NINE
What is hemophilia caused by?
caused by severe different X-linked recessive gene abnormalities = the gene abnormalities are inherited through the mother and that nearly everyone with hemophilia is male
What are the bleeding patterns and consequences of these two types of hemophilia?
hemarthrosis, bruising, and bleeding
What is the main symptom of hemophilia?
excessive bleeding
- the bleeding may be into a joint or muscle, inside the abdomen or head, or from cuts, dental procedures, or surgery
- recurring bleeding into the joints and muscles can lead to crippling deformities
- bleeding can swell the base of the tongue until it blocks the airway, making breathing difficult
- a slight bump on the head can trigger substantial bleeding in the brain or between the brain and the skull, causing brain damage and death
- a child who has hemophilia bruises easily
- even an injection into a muscle can cause bleeding that results in a large bruise and hematoma
What does the severity of the bleeding depend on?
depends on how a particular gene abnormality affects the blood clotting activity of factor VIII or IX
What are the characteristics of mild hemophilia?
- people whose clotting activity is 5 to 25% of normal have mild hemophilia that may go undiagnosed
- these people may bleed more than expected after surgery, dental extraction, or a severe injury
What are the characteristics of moderate hemophilia?
- people whose blood clotting activity is 1 to 5% of normal have moderate hemophilia
- they have few unprovoked bleeding episodes, but surgery or injury may cause uncontrolled and fatal bleeding
What are the characteristics of severe hemophilia?
- serious episodes of bleeding occur and recur after a minor injury or for no apparent reason
- in severe hemophilia, the first bleeding episode often occurs during or immediately after delivery
- the infant may develop a collection of blood under the scalp (cephalhematoma) or may bleed excessively during circumcision
- in serve or moderate hemophilia, a bleeding episode generally occurs before 18 months of age and may follow a minor injury
How is hemophilia dx?
increase PTT, normal PT, and platelets, with decreased Factor VIII or IX on assay
- increased PTT and normal platelet count and function
- corrected with mixing studies = indicates a factor deficiency
- if PTT does not correct with mixing studies indicates lupus anticoagulant or factor inhibitor
- normal PT
- normal bleeding time
- most specific test: functional assay for factor VIII (Hemophilia A) or IX (Hemophilia B) to confirm the diagnosis of hemophilia and determine its type and severity
What is the treatment of Hemophilia?
treatment often involves the replacement of factor VIII or IX
- people who have hemophilia should avoid situation that might provoke bleeding and should avoid drugs (for example, aspirin and probably also NSAIDs) that interfere with function of platelets
- they should be conscientious about dental care so that they will not need to have teeth extracted
What is the most common environmental illness of children in the United States?
lead poisoning
What are the characteristics of lead poisoning?
- in children, most organs are susceptible to lead poisoning, especially the brain
- therefore, lead poisoning must remain high on the differential list for pediatric patients
What is the most significant source of lead toxicity in children?
environmental exposure
- including exposure to lead-based paint, food, water, and soil
- classic case of lead poisoning involve children inside an old house with paint chips
What are the symptoms of lead toxicity in children?
non-specific
- behavioral changes, temperamental lability, irritability, hyper/hypoactivity, developmental delays, abdominal pain, vomiting, constipation, lethargy, headache, ataxia, and seizures
- lead poisoning can also cause anemia
How is lead poisoning dx?
once lead poisoning is suspected, whole blood lead levels need to be obtained
- a level of 10 ug/dl is considered positive
- increased serum blood lead level
- basophillic stippling
- decreased or normal MCV
- decreased mean MCH
- hemolysis
- increased indirect bilirubin, LDH
- decreased haptoglobin
What is the tx of lead poisoning?
treatment includes preventing further exposure, chelation therapy, and dietary measures
- dimercaprol, CaNaEDTA, penicillamine, and succorer are all agents that can be used to treat lead toxicity
- typically chelation therapy is only indicated if a patient has a blood lead level of ~45 ug/dL
- patients are hospitalized when the levels are about 70 ug/dL
- contact with local health department is only necessary when patients have blood level of greater than 20 ug/dL or if after 3 months the level remain elevated
- siblings and other children who live in the household or attend the same school or daycare should be tested
What accounts for the greatest percentage of cases of childhood malignancies?
leukemia
- there are 3,000 new cases of leukemia each year in the US
- acute leukemia constitutes 97% of all childhood leukemias and is subdivide into acute lymphocytic leukemia (ALL) and acute nonlymphocytic anemia, also known as acute myelogenous leukemia (AML)
- chronic leukemias make up 3% of childhood leukemias
What are characteristics of Acute lymphocytic leukemia?
- CHILD + Lymphadenopathy + bone pain + bleeding + fever in a CHILD, bone marrow >20% blasts in bone marrow
- the most common pediatric neoplasm accounts for 80% of all cases of childhood acute leukemia
- most common childhood malignancy peak age 3-7 y/o
- highly responsive to chemotherapy (remission >90%)
- ANC < 1000
What are the characteristics of acute myelogenous leukemia?
- AML accounts for 20% of all cases of childhood leukemia
- far more common in males than females
- patients with AML may develop a soft-tissue tumor called a chroma in the spinal cord or skin
- the lesion shave a greenish hue
- smear Auer rods