Hematologic Diseases and Neoplasms Flashcards
Causes of aplastic anemia
- Idiopathic
- Radiation
- Medications (chloramphenicol, sulfonamides, gold, and carbamazapine)
- Viral infections (parvovirus, hep B and C, EBV, CMV, HZV, HIV)
- Chemicals (benzene and insecticides)
Aplastic anemia treatment
Bone marrow transplantation
Transfusion of PRBC or platelets
Vitamin B12
- converts homocysteine to methionine
- converts methylmalonyl CoA to succinyl CoA
- Stored in liver
Neurologic effects of B12 deficiency
- Demylination of the posterior columns, lateral corticospinal tract, and spinocerebellar tract (loss of position/vibratory sensation in the lower extremities, ataxia, and upper motor neuron signs)
- Urinary and fecal incontinence
- Dementia
Schilling test
- Give IM dose of unlabeled B12 to saturate binding sites
- Give oral dose of radioactive B12 and then measure the serum and urine levels to determine absorption
- Repeat the test (oral radioactive B12) with the addition of intrinsic factor.
Causes of folate deficiency
- Inadequate dietary intake
- Alcoholism
- Long-term oral antibiotics
- Increased demand
- Pregnancy
- Hemolysis
- Methotrexate
- Phenytoin
- Hemodialysis
- most common cause of megaloblastic anemia in alcoholics.
Hemoglobinuria
intravascular hemolysis
extravascular hemolysis - Peripheral smear
helmet cells and spherocytes
G6PD - peripheral smear
Heinz bodies
Haptoglobin in hemolytic anemia
low because it binds to hemoglobin (which is being destroyed)
Hemolytic signs of sickle cell anemia
- jaundice, pallor
- pigmented gallstones
- high output CHF
- aplastic crisis
Veno-occlusive signs of sickle cell anemia
- bone infarction
- hand-and-foot syndrome (dactylitits - avascular necrosis of the metacarpal and metatrasal bones)
- acute chest syndrome - recurrent pulmonary infarction
- splenic infarction
- avascular necrosis of joints - esp hips and shoulders
- priapism - vaso-occlusion of the penis
- CVA
- Opthalmologic - retinal infarcts, vitreous hemorrhage, proliferative retinopathy, retinal detachment
- Renal papillary necrosis
- chronic leg ulcers - esp over left lateral malleolus
- Abdominal crisis
Treatment for priapism
hydralazine, nifedipine, or silbestrol (antiandrogen)
Splenic sequestration crisis
pooling of blood in the spleen leading to splenomegaly and hypovolemia
Sickle cell anemia treatment
- Hydroxyurea - increases HbF (chronic)
- Fluids, morphine, warmth, and oxygen (acute)
- Blood transfusion in CLINICALLY unstable pts
- folate supplements
- penicillin prophylaxis 4mo-6yrs
- vaccines against encapsulated organisms
- bone marrow transplant
Hereditary spherocytosis
- Autosomal dominant defect in genes for spectrin, ankyrin, and other RBC membrane proteins
- Loss of RBC membrane
- Extravascular hemolysis by spleen
- RBC osmotic fragility test (acidified glycerol lysis test)
- Abnormal eosin-5 maleimide binding test
- Elevated reticulocyte count and MCHC
- Treat with splenectomy
- At risk for aplastic crisis and pigmented gallstones
- Common in Northern Europeans
- Jaundice and splenomegaly due to RBC getting trapped and hemolyzing in the splenic fenestrations.
- Hemoglobinuria.
G6PD Deficiency
- X-linked autosomal recessive
- G6PD is an enzyme that creates NADPH, a cofactor required to create glutathione
- Causes build-up of H2O2 which causes precipitation of HGB as Heinz bodies (leads to bite cells)
- Precipitated by drugs (nitrofurantoin, sulfonamides, primaquin, dimercaperol) and infection.
- Mild form involves only old RBC (AA); severe form (Mediteranean)
- Deficient NADPH formation on G6PD assay and reduced G6PD.
- G6PD may be normal during an acute attack.
Monoclonal gammopathy of undetermined significance
Asymptomatic, premalignant condition that can progress to multiple myeloma (20%)
Diagnosis: IgG spike
Multiple Myeloma
General characteristics: enormous amounts of monoclonal immunoglobulins (IgG or IgA)
- More common in African Americans
Clinical features: CRAB (calcium, renal, anemia, bone pain)
- bone pain in lower back, ribs and jaw
- recurrent infections (pneumonia and UTI most common cause of death)
- Anemia
- Renal failure
- Elevated beta-2 microglobulin
- Cord compression due to plasmacytoma or bone fragment (get MRI and starts steroids)
Diagnosis:
at least 10% abnormal plasma cells in the bone marrow + 1 of the following:
- M protein in the serum >/= 3g/dL
- M protein in the urine
- Lytic bone lesions (predominantly in the skull and axial skeleton)
- Get serum and urine electrophoresis
- Hypercalcemia, elevated total protein, elevated ESR, rouleaux formation on peripheral smear, pancytopenia
Treatment: hematopoeitic cell transplantaion is best, chemo is reserved for those not able to do HCT, radiation is palliative
Waldestrom’s macroglobulinemia
- Malignant proliferation of plasmacytoid lymphocytes that produce IgM.
Diagnosis: IgM>5g/dL, Bence Jones proteinuria, and no lytic bone lesions
- Lymphadenopathy, neurologic symptoms, splenomegaly, anemia, abnormal bleeding, and hyperviscocity, night sweats, headache, dizziness, visual problems, demyelinating sensorimotor neuropathy
Treatment: none, use chemo and plasmaphoresis to control hyperviscocity
Intravascular hemolysis
- Microangiopathic hemolytic anemia
- transfusion reactions
- Infections (clostridial species)
- paroxysmal nocturnal hemoglobinuria
- IV Rho(D) immune globulin infusion
Extravascular hemolysis
- Intrinsic RBC enzyme deficiencies
- Hemoglobinopathies (sickle cell anemia, thalassemia)
- Membrane defects
- Hypersplenism (IV immunoglobulin infusion)
- Warm or cold agglutinin autoimmune hemolytic anemia
- Infections (malaria, Bartonella)
Idiopathic thrombocytopenic purpura
- Due to IgG autoantibodies against the platelet membrane glycoproteins
Clinical presentation: previous viral infection, bruising and bleeding
Labs: isolated thrombocytopenia, peripheral smear w/ megakaryocytes and no other abnormalities
Treatment: children with skin manifestations only - observation
Children with bleeding - IVIg or steroids
Adults with platelets >/=30,000 w/o bleeding - observation
Adults with platelets
Bernard-Soulier syndrome
- Autosomal recessive
- Absent platelet glycoprotein Ib-IX-V (receptor for von Willebrand factor)
- mild thrombocytopenia w/ giant platelets, severe platelet dysfunction, and bleeding out of proportion with the thrombocytopenia