Hematology Flashcards
Hct 25 - 30%
Dyspnea (worse on exertion ), fatigue
Hct 20 - 25%
Lightheadedness, angina
Hct < 20%
Syncope, chest pain
Causes of cardiac ischemia
- anemia
- hypoxia
- coronary artery disease
- carbon monoxide poisoning
Causes of microcytosis
LITS
- Lead poisoning
- Iron deficiency
- Thalassemia
- Sideroblastic anemia
Microcytosis
- low MCV
- low reticulocyte count
Causes of macrocytic anemia
- B12 and folate deficiency
- Sideroblastic anemia
- Alcoholism
- Liver disease or hypothyroidism
- Medications (e.g. zidovudine or phenytoin)
- Myelodysplastic syndrome
- Antimetabolite rx: azathioprine, 6-MP, or hydroxyurea
Under normal circumstances, situations that raise reticulocyte count
- Blood loss
- Hemolysis
Normocytic anemia
- acute blood loss
- hemolysis
Treatment of severe anemia
- Packed red blood cells
When do you transfuse a patient:
- If patient is symptomatic
2. Low hct in an elderly pr or one w/ heart disease.
Symptomatic from anemia
- SOB
- Lighthead, confused, and sometimes syncope
- Hypotension and tachycardia
- Chest pain
Packed Red Blood Cells
- concentrated form of bloos
- whole blood w/ 150ml plasma removed
- Hct is 70 - 80%
- 1 unit of PBRCs raise Hct by about 3 points per unit
Fresh Frozen Plasma
- replaces clotting factors in pts with elevated PTT, aPTT, or INR
- used as replacement w/ plasmapheresis
Blood products for IgA deficient donor
IgA deficient donor FFP
Cryoprecicipate
- used to replace fibrinogen
- some utility in DIC
- provides high amts of clotting factors in smaller plasma volume
- High factor VIII and VWF
Microcytosis
- MCV lower than noral
- usually below 80fL
Iron deficiency
- caused by blood loss
- Fe needs for 1 - 2mg /day
- menstruating women need 2 - 3 mg /day
- pregnant women need 5 - 6 mg/day
- Fe absorbed in duodenum
Chronic disease
- caused by cancer or chronic infxn
- Fe is locked in storage or trapped in macrophages or in ferritin
- hemoglobin synthesis can’t move forward
Anemia in renal failure
Deficiency of erythropoiestin
- MCV is initially normal then decreases
Sideroblastic anemia
- can be macrocytic as well associated w/ myelodysplasia, preleukemic syndomre
Common causes of sideroblastic anemia
- Alcohol suppressive effect on marrow (MCC)
- Lead poisoning
- Isoniazid
- Vit B6 deficiency
Thalassemia
- extremely common cause of microcytosis
- most patients are assymptomatic
Pt with anemia and c/o blood loss (GI Bleeding). Likely dx?
Iron deficiency
Mensturating woman c/o anemia. Likely dx?
Iron deficiency
Pt with cancer or chronic infxn is anemic. Likely dx?
Anemia of Chronic dix
Anemic Pt with rheumatoid arthritis. Likely dx?
Anemia of chronic disease
Alcoholic pt has anemia. Likely dx?
Sideroblastic anemia
Asymptomatic pt with anemia. Likely dx?
Thalassemia
Most common way to diagnosis microcytic anemia.
Peripheral smea
- target cells are most common w/ thalassemia
Pt has low ferritin. Likely dx?
Iron deficiency
Pt has high iron. Likely dx?
Sideroblastic anemia
Pt has normal iron studies. Likely dx?
Thalassemia
Iron deficiency
- low ferritin is extremely specific for Fe deficiency
- increased TIBC b/c of lots of unbound sites on receptors
Chronic disease
- serum is low in circulation b/c Fe is trapped in storage
- Stored Fe (ferritin) elevated or normal
- Circulating Fe is decreased
- Low TIBC
Sideroblastic anemia
- only microcytic anemia with elevated Fe level
Thalassemia
- genetic disease w/ normal Fe
Unique lab features of Fe deficiency
- increased RDW b/c new cells are more FE deficient and smaller
- as body runs out of Fe, newer cells have less hemoglobin
- elevated platelet count
Unique lab fx of sideroblastic anemia
Prussian blue staining for ringed sideroblastic anemia is msot accutate test
- basophilic stippling can occur in any cause of sideroblastic anemia
Unique lab features: thalassemia
Hemoglobin electrophoresis is most accurate diagnostic test
Alpha thalassemia
3 genes deleted shows moderate anemia with hemoglobin H, whihc are beta-4 tetrads
- increased reticulocytes
Hemoglobin Bart
- four genes deleted
- gamma 4 tetrads
= CHF causes death in utero
Beta thalassemia
- increased hemoglobin F and A2
Beta thalassemia intermedia
- normal hemoglobin F
- no transfusion dependence
Iron deficiency tx
- replace Fe with oral ferrous sulfate
- occasionally pts w/ IM Fe
Tx of anemia of chronic disease
- correct underlying disease
- onlt anemia associated w/ ESRD responds to erythropoietin
Tx of sideroblastic anemia
Correct underlying cause
- respond to Vitamin B6 or pyroxidine replacement
Tx of thalassemia
- Trait can’t be treated
- Beta thalassemia major managed w/ lifelong chronic transfusion
- Iron overload is managed by deferasirox or deferipone
Megaloblastic anemia
- presence of hypersegmented neutrophils
- B12 and folate deficiency and antimetabolite medications cause hypersegmeneted neutrophils
Vitamin B12 deficiency: Causes
- Pernicious anemia
- PANCREATIC INSUFFICIENCY
- Dietary deficiency
- Crohn dx or any disease damaging terminal ileum
- Blind loop syndrome (gastrectomy or gastric bypass)
- Diphyllobothrium or HIV
Folate deficiency: causes
- Dietary dfeficiency (goat’s milk has no folate and provides limited Fe)
- Psoriasis and skin loss or turnover
- Drugs: phenytoin and sulfa
Celiac disease causes what nutritional deficiencies?
Vitamin B12
Folate
Iron deficiency
Clinical findings which differentiate folate and Vit B12 deficiencies
B12 have neurological abnormalities
- peripheral neuropathy is most common
- dementia is least common
- posterior column damage to vir
Causes of neurological findings in Vit B12 deficiency
Posterior column damage to position and vibratory sensation or “subacute combined degeneration
of cord
- look for ataxia
Dx tests associated with folate and Vit B12 deficiency
- megaloblastic anemia
- increased LDH and increased indirect bilirubin leveles
- decreased reticulocyte count
- hypercellular bone marrow
- macroovalocytes
- increased homocysteine levels
Lab test differences btwn folate and vitamin B12 deficiencies
Both folate and Vit B12 deficiencies have increased homocysteine
ONLY B12 have increased methylmanonic acid (MMA)
Confirmation of parietal anemia
- cause of macrocytic anemia
Confirmed with anti-instrinsic factor and anti-parietal cell antibodies
Why are reticulocyte counts so low in setting of macrocytic anemia
Red cells are destroyed as they leave the marrow, so the reticulocyte is low
Why does pancreatic insufficiency important for B12 deficiency
Pancreatic enzymes needed for absorption of Vitamin B12
What is a complication of B12 and folate replacement?
Hypokalemia
- Reintroduction of B12 and folate causes cells to be produced so rapidly so that marrow packages serum K quickly
Obstructive Sleep Aonea
- recurrent transient obstruction of upper airwy dur to pharyngeal collapse during sleep
- usually patients are overweight
Obstructive Sleep Apnea: Sx
- excessive daytime sleepiness
- snoring
- morning headaches
- impotence
- arterial hypertension
Discuss OSA and erythropoeitin
- OSA causes short term hypoxemia which is sensed by kidneys and stimulaes increased erythropoetin production
- increased epo can cause polycythemia
TTP
- patients with hemolytic anemia and thrombocytpenia
- altered mental status, renal failure and fever are common
- defect in ADAMTS13
Best test for TTP
** peripheral blood smear ( can see
TTP: Hx and PE
- low platelet count
- microangiopathic hemolytic anemia
- neuro changes (delirium, seizure, stroke)
- impaired renal fxn (incr. BUN:Cr)
- fever
- be suspicious if 3/5 are present
3 causes of microangiopathic hemolytic anemia
- HUS
- TTP
- DIC
Management of severe hypercalcemia (Ca > 14)
Short term
- normal salne hydraton plus calctionin
- avoid loop diuretics unless volume overload
Long term
- Bisphosophates (zoledronic acid)
Management of asymptomatic or mild hypercalcemia (ca < 12)
- No immediate treatment required
- avoid thiazide diuretic and lithium use
B-thalassemia
- usually of Med descent
- asymptomatic w/ mild anemia
- disproportionately high RBC count
- low MCV
- target cells on smear
B-thalaseemia on electrophoresis
- elevated hemoglobin A2 on electrophoresis
Tx of B-thalaseemia
- Reassurance w/ no specific therapy required
A-thalassemis
- pts missing 2/4 alpha globin chains
- asymptomatic w/ mild anemia
- MCV < 75
- target cells on peripheral semar
- normal hemoglobin electrophoresis
Heparin Induced Thrombocytopenia
- heparin induced released of PF4 from platelets form heparin-PF4 complexes
- IgG antibodies against heparin-PF4 complexes causes platelet activation, endothelial cell activation
- increased PTT due to thrombin consumpton
Pt has thrombocytopenia and hypercoagulation w/in days of initiating anticoagulation therapy. Likely dx?
HIT due to unfractionated heparin or low weight molecular heparin
Hairy cell leukemia
- B-lymphocyte derived chronic leukemia
- lymphocytes have fine, hair-like irregular projections
- bone marrow may become fibrotic thus may lead to dry tap
- TRAP (tartrate resistant acid phosphotase) stain
Tx of hairy cell leukemia
- Cladribine (purine analog)
can be toxic to bone marrow and adverse effect include neurological and kidney damage
Hereditary spherocytosis
- usally autosomal dominant
- triad: hemolytic anemia, jaundice, and splenomegaly
- increased risk for bilrubin gallstones & infxn from parvovirus B19
Hereditary spherocytosis: Lab findings
- reticulocytye count from 5- 20%
- normal to low MCV
- increased MCHC indicating membrane loss & dehyrdration
- spherocytes on peripheral smear
- Negative Coombs test
Heme manifestations of SLE
Pancytopenia
- Anemia: due to chronic dx, renal insuffuciency, and AHA
- Leukopenia: autoimmune destruction
thrombocytopenia: immune mediated
Acute hemolytic transfusion reaction
Rxn from transfusion of mismatched blood (ABO)
- starts WITHIN HOUR of transfusion
- pts: have fever, chills, hemoglobinuria, FLANK PAIN and discomfort and site
Dx of acute hemolytic transfusion rxn
- positive direct Coombs test
- pink plasma (plasma free hemoglobin > 25)
- Hemoglobinuria
- Repeat type and cross-match shows missmatch
Management of acute hemolytic transfusion reaction
- Immediate cessation of transfusion while mantainig IV access and supportive care
Delayed hemolytic transfusion
- from anamanestic antibody response to a red blood antigen to which pt was previously sensitized
- causes low-grade hemolysis WITHIN 2-10 days
IgA deficiency
rapid onset of shock, angioedema/urticaria & respiratory distress
- occurs WITHIN SECONDS-MINUTES of tranfusion
- caused by recipient of anti-A IgG antibodies
Mgmt of anaphylaxis due to IgA deficiency
- Epinepherine with circulatory and respiratory support
Giant cell tumor of bone
- benign and locally aggressive skeletal tumor that presents w/ pain, swelling, and decreased range of motion
- “Soap-bubble” appearance on X-rays
- usually in epiphyseal regions of long bones and involves distal femur and proximal tibia around knee joint
Osgood Schlatter disease
- overuse injury caused by repetitive strain
- seen in young children and teens who have undergone rapid growth spurt
- X-ray shows avulsion apophysis of tibial tubercle
Esophageal cancer
- squamous cell most common worldwide
- adenocarcinoma most popular in US, Europe and Australa
Risk factors for esophageal squamous cell carcinoma
Alcohol and tobacc
Risk factors for adenocarcinoma
- Barrett’s esophagus (columnar metaplasia distal esophagus)
Hx/PE: for esophageal cancer
- progressive dysphagia initially to solid then liquids
- weight loss, odynophagia, GERD, GI bleeding and vomiting
Dx of esophageal cancer
Barrium swallow followed by EGD w/ biopsy
Tx of esophageal cancer
Chemoradiation and surgical resection is first line treatment
- has poor prognosis
Location of SCC of esophagus
in upper and middle 1/3 of esophagus
Location of adenocarcinoma of esophagus
in lower 3rd
Lynch Syndrome / HNPCC
- > 3 relatives w/ colorectal (1 must be 1st deg relative)
- involvement in > 2 generations
- at least one case diagnosed before 50
- Exclusion of FAP
Lynch Syndrome I vs Lynch Syndrome II
Lynch Syndrome I - hereditary site specific colon cancer
Lynch Syndrome II - incr risk for extracoloni
Vitamin B 12
-Macrocytic, megaloblastic anemia)
Neuro sx (optic neuropathy, subacute combined degenearation, parasthesias)
- Glossitis
Leading cause of B12 deficiency
Pernicious anemia
- antibodies to IF needed for b12 absorption
- chronic gastritis for decr. production of IF
Long term complications of pernicious anemia
Gatric cancer
ITP
IgG are formed against patient’s platelets
- most common immunologic disorder in women of childbearing age
Hx/PE: ITP
pts generally feel well but present w/
- easy bruising, petechiae, hematuria, hematemesis or melena
ITP associated w/ which conditions
- Lymphoma
- Leukemia
- SLE
- HIV
- HCV
Acute ITP
abrupt onset of hemorrhagic complications following viral ilness
- usually in children 2-6 y.o
Chronic ITP
insiduous onset unrelated to infext
- often affects adults 20 - 40
- females 3x more likely affected than males
Dx of ITP
- DIAGNOSIS OF EXCLUSION
- can be confirmed w/ hx and pe, CBC, and peripheral blood smear
