Hematology Flashcards
What are the factors of the extrinsic pathway?
7–>X–>5–>2 (Prothrombin)–>2a (Thrombin) –>1 (Fibrinogen)–>Fibrin–>13 (Tight clot)
NB: X marks the spot for the common pathway
NB2: 13 is not measured in PTT or PT
What are the vitamin K dependent factors?
10, 9, 7, 2 (1972 - it was a good year!)NB: Vitamin K is more associated with the extrinsic pathway.
What happens if you are deficient in Protein C or Protein S?
You clot out of control (predisposed to major thrombosis)
What are the factors of the intrinsic pathway?
TENET - Twelve, Eleven, Nine, Eight, Ten (common)Then remainder of common pathway - 5, 2, 2a, 1, Fibrin, 13
aPTT/PTT measures coagulation in which pathway?
Instrinsic (PITT)
PT measures coagulation in which pathway?
Extrinsic (PET)
What is PT used for?
- extrinsic and common factors
* used to monitor Coumadin patients
What happens to PT with a Vitamin K deficiency?
It is prolonged
When is PTT prolonged?
- von Willebrand disease
- hemophilia
- lupus anticoagulant
- NB: sensitive to Heparin contamination
What does a 1:1 mixing study tell you?
- if it corrects into the normal range, a factor deficiency is the likely culprit
- if it fails to correct, an inhibitor or anticoagulant is the likely suspect
- NB: 30% activity is the threshold to correct clotting times
What is the Platelet Function Assay (PFA-100)?
- modern test that replaces old “bleeding time” test
- push blood through a coated filter and watch the clot formation time on the filter
- need platelets at least 100 x 109/L
When will the Platelet Function Assay be prolonged?
- von Willebrand disease
- aspirin
- platelet function defects
What does a Normal PT/PTT indciate in the presence of a bleeding disorder?
Factor XIII deficiencyRemember, it is not measured by PT/PTT
What does both an abornmal PT and PTT suggest?
- fibrinogen deficiency/problem
- Vitamin K deficiency
- DIC
- Liver disease (PT abnormal first)
What does an abnormal PTT with normal mixing result suggest?
- Hemophilia A or B
- Von Willebrand disease
- Factor XI deficiency
- Factor XII deficiency
What might cause a fibrinogen deficiency?
- liver dysfunction
* DIC
Can a reduced level of fibrinogen cause a prolonged PT, PTT or Thrombin Clot Time?
- Generally, no unless fibrinogen is less than 100 mg/dL
What does Thrombin Clot Time (TT) measure?
Measures the time for conversion of fibriongoen to fibrinHeparin can contaminate
What is von Willebrand disease?
- Caused by a deficiency or reduced functioning of von Willebrand factor
- carries and stabilizes factor VIII
- mediates platelet adhesion and aggregation
What is the most common inherited bleeding disorder?
von Willebrand disease
What is the mechanism of inheritance of von Willebrand disease?
Usually autosomal dominant
What is the Rx for von Willebrand’s disease?
- DDAVP (Arginine vasopression) - releases stored vWf from endothelial cells
- reduced efficacy with repeated dosing (tachyphylaxis)
- Humate-P - factor VIII product that contains vWf
- Cryoprecipitate - life-threatening bleeds (infectious transmission risks)
- Aminocaproic acid - Amicar -supportive, effective for mucosal bleeding. acts by stabilizing clot. No for hematuria
What is Hemophilia A?
Deficiency or lack of Factor VIII
What is Hemophilia B?
Lack or deficiency of Factor IX
How are Hemophilia A and B transmitted?
X-linked recessive disorders
What are the three degrees of severity of hemophilia?
- Mild Hemophilia (30-40% of cases)- Factor level 6-50%/uncommon spontaneous bleeding/see sx after major trauma or surgery
- Moderate hemophilia (10% cases) - factor level 1-5%/see sx after minor trauma/4-6 bleeding episodes per year
- severe hemophilia (50-70%) - Factor level <1%/spontaneous bleeding occurs/2-4 x month
What type of bleeding episode is most common in hemophila?
joint bleeding (60%)most common sites are knee, ankle, elbow
What should you avoid when treating a joint bleed?
NSAIDS and Aspirin (you know why)
What are the possiblecomplications of untreated muscle bleeds?
- foot drop
- flexed hip
- volkmann’s contracture (hand arm)
- compartment syndrome
What is the treatment for Hemophilia?
- replacement of missing factor concentrate (on demand/prophylaxis)
- DDAVP/ Stimate - not for B
- Antifibrionolytic agents - Amicar
- Supportive measures - RICE and pain control
What are factor inhibitors and how do you identify when they exist?
- these are antibodies that develop against “foreign” infused factors in hemophilias. They exist in 15-25% of Factor VIII pts and 1.5-3% of Factor IX pts.
- median of 9-12 exposure days
- consider when pt. is unresponsive to Rx
- prolonged PTT after mixing 1:1
- one BU of activity causes 50% loss of Factor VIII activity
How do you treat inhibitors in hemophilia?
- recombinant FVIIa - push clotting through extrinsic pathway
- High-dose VIII or IX
- prothrombin complex concentrates
- can try to desensitize the immune systemto the factor
What is DIC?
- A disorder of secondary hemostasis caused by consumption of factors in the coagulation system
- triggered by exposure of blood to tissue factor
- present with bleeding, petechiae and purpura
- causes include: infection; major trauma; malignancy
What is the Rx for DIC?
- Most important: TREAT UNDERLYING CAUSE
- hydration
- RBC transfusion
- if bleeding, fresh frozen plasma, cryoprecipitate, orplatelets
What are conditions that can lead to thrombosis?
Virchow's Triad * alterations in blood flow (stasis) * vascular endothelial injury * alterations in constituents of blood 50% of thrombotic events in pts with inherited thrombophilia are affiliated with additional risk factor
What are the causes of inheritied thrombophilia?
- Factor V (Leiden) - most common inherited in causasians 3-8%
- prothrombin gene mutation (G20210A)
- Protein S deficiency
- Protein C deficiency
- antithrombin deficiency
What is the Rx for venous thromboembolism?
- LMW heparin, vondaparinaux, unfractioned IV heparin
- overlap with and transition to Vitamin K antagonist
- Target INR 2.5
Who should be screened for thrombophilia?
- initial thrombus occuring before 40 without provoking factor
- FH of 1st degree relatives with VTE
- recurrent VTE
- thrombosis in unusual vascular beds - liver, cerebral, mesenteric
What are secondary hypercoagulable states?
- pregnancy
- contraceptive use/HT
- malignancy
- systemic inflammation
- post-operative state
- immobilization
- trauma
Elevated Reticulocytes Indicate..
Hemoglobinopathies• RBC MembraneDefects• Enzyme deficiencies
Decreased Recitulocytes indicate…
Fe deficiency• Lead poisoning• Inflammation• Bone marrow failures syndromes
Hemolytic Anemia Signs/Sx:
Pallor, fatigue
Jaundice, dark urine
Splenomegaly, gallstones
Hemolytic Anemia Lab Findings
Reticulocytosis, AnemiaElevated bilirubinElevated AST > ALTElevated LDH
Hereditary Spherocytosis (HS) Characteristics
Spherocytes: smaller, loss of central pallorCongenital hemolytic anemia• Most common inherited anemia in individuals ofnorthern European descent • Autosomal Dominant Inheritance• ~1/3 are spontaneous mutationsMutations affect RBC membrane• Spectrin, ankyrin• Loss of membrane surface area relative to intracellularvolume
Hereditary Spherocytosis Clinical Signs/Sx
Neonatal jaundice• First 24 hours of life• Exaggerated, prolonged physiologic nadirOutside the newborn period:• Incidental Laboratory findings• Acute aplastic event (Parvovirus B19)• Jaundice, Splenomegaly, early gallstones
Parvovirus B19 infection Characteristics
• “5th Disease”• Clinical manifestations: URI/pharyngitis, rash (“slapped cheeks”), Very mild anemia• Infects RBC precursors for 7-10 days so rapid decrease in red calls daily• Dx: serology (IgM)
Hereditary Spherocytosis Levels of Infection
Depends on Spectrin Content: Mild HS: 20-30% of cases, No anemia, sight Reticulocyte increase, Mild jaundice
Moderate HS: 65-75% of cases, + anemia, +Reticulocytes, + Bilirubin, ± splenomegaly, Occasional transfusions
Severe HS: 5% of cases, ++ anemia, ++Reticulocytes, ++ Bilirubin, Marked splenomegaly, Regular transfusions
Hereditary Spherocytosis Lab Findings
AnemiaReticulocytosisMCHC typically > 36%
Wide RDW (small spheres and large reticulocytes)
Often elevated bilirubin, LDH, AST>ALTPresence of spherocytes on peripheral blood smear
Hereditary Spherocytosis Diagnostic Test results
Negative Direct Antiglobulin Test (DAT/Coombs)Positive Osmotic Fragility Testing: decreased surface area means no room to swell so burst.
Hereditary Elliptocytosis (HE) Characteristics:
• Elliptical, cigar shaped, erythrocytes• Normochromic, normocytic, may or may not be anemic• Defect in spectrin• African and Southeast Asian Variants: 1:100 in parts of Africa• Autosomal Dominant• Many asymptomatic: RBC lifespan decreased by only ~10%
Hereditary Pyropoikilocytosis (HPP) Characteristics:
• Newborns with severe hemolytic anemia:– Anemia, jaundice– Poikilocytosis, elliptocytosis, and spherocytosis– Fragments of cells so intra & extravascular lysis• Gradually evolves into mild HE
G6PD Deficiency Characteristics
Most common human genetic mutation: X-linked High prevalence re malaria protection> 400 missense Genetic mutations: A- variant most common among African descent Mediterranean variant more severeEffects of G6PD deficiency Incomplete protection against oxidative stressAcute hemolytic anemia after exposure to oxidative stress: Infections Sulfa drugs Naphthalene (moth balls) Fava beans
G6PD Deficiency Signs/Sx:
Acute fatigue, jaundice, pallor,dark urine (intravascular hemolysis),+/- history of known trigger
G6PD Deficiency Diagnostic Lab findings:
• Normocytic, normochromic anemia• Reticulocytosis
Elevated LDH, Bilirubin**
Hemoglobinuria (+ for blood, no RBCs on microscopic urine)** Blister cells, anisocytosis on blood smear**Assay G6PD activity after resolution of a hemolytic crisis
Autoimmune Hemolytic Anemia (AIHA) characteristics:
Incidence: 1 - 3/100,000, children and adultsVariable clinical course: self-limited, short illness, waxing and waning, chronic illnessPrognosis typically good: Morbidity from treatment, Mortality <10%Erythrocyte autoantibodies: IgG, IgM, Complement fixationTypes: Warm vs. ColdLab Test: Direct Antiglobulin Test (Coombs test)
Warm-Reactive AIHA characteristics:
IgG autoantibody mediated RBC destruction (G for Georgia = Warm)• Bind RBC surface at warmer temperatures* Extravascular hemolysis—Fc Receptors in the spleen• Occasionally fix complement leading to lysisTypes: -Idiopathic-Immunodeficiency -Secondary: EBV infection
Direct Antiglobulin Test (DAT)AKA “Coombs Test”: How does it work?
Sensitized Erythrocytes+Coombs reagent (anti-IgG, anti-C3) =Visual RBC Agglutination (1+ to 4+)
Warm-Reactive AIHA Signs/Sx:
• Typically rapid onset anemia• Can be life threatening• Fatigue, dyspnea, heart failure• Scleral Icterus, Jaundice, +/- dark urine (hemoglobinuria)• Splenomegaly
Warm-Reactive AIHA Labs:
• Anemia and reticulocytosis• Spherocytes on peripheral blood smear• Positive DAT+ IgG, ± Complement (C3)
Warm-Reactive AIHA
Transfusion will not be 100% compatible but may be necessary (Least Incompatible)Glucocorticoids: Once remission has been achieved, wean steroids SLOWLY and mimic physiologic dosing as much as possible (AM dosing)SplenectomyRituximab: Monoclonal antibody directed against CD20 on B-cell surface
Cold Agglutinin Disease(Cold Reactive AIHA) Signs/Sx:
Erythrocyte agglutination upon exposure to cold• Mottled or numb fingers and toes• Acrocyanosis (blue extremities)
Cold Agglutinin Disease(Cold Reactive AIHA) Labs:
• Mild anemia with reticulocytosis** Red cell agglutination on PBS made at room temperature (but not at 37 C)!** DAT (Coombs) will be positive for complement (C3) only
Cold Agglutinin Disease(Cold Reactive AIHA) Treatment
Largely symptomatic–Avoid cold! Rituximab re active or relapsing symptomatic hemolysisSplenectomy and corticosteroids ineffective so avoidIf transfusion is needed—Warm the RBCs!
DDX re Warm-Reactive AIHA vs Cold-Reactive AIHA
Warm-Reactive AIHA: IgG, DAT result: +IgG, ± C3 (C3 fixation Variable) Thermal reactivity 37C, RBC destruction: Spleen,
Tx: Steroids, Splenectomy
Cold-Reactive AIHA: IgM Thermal reactivity: 4C +C3 (C3 fixation) RBC destruction: Liver Common therapy: Avoid cold, Rituximab
Hb/Hgb
the concentration of hemoglobin: oxygen carryingproteins2 beta and 2 alpha chains. each chain has associated heme group and each heme group has a central iron which binds oxygen.
HCT (%)
Hematocrit percent (should be 3x hemoglobin)% of blood volume occupied by RBC
what does MCV mean?
mean cell corpuscular volume:tells us the average volume of RBCs collected.relates to RBC size to tell if micro=<80, normo=80-100, or macrocytic>100neonates 110 normal, 70 at 1 year oldif larger, it’s newer cells (macrocytic)
MCH
Mean cell hemoglobin: average Hb concentration of the RBCs(when cell size change,
what is MCHC?
Mean [Hg] per ONE Red blood cell
What does a Reticulocyte Count mean?How do you evaluate for Anemia?
a direct reflection of rate of RBC productionindirect reflection of rate of RBC destruction (elevated in disorders with more destruction)(reported as % and an absolute number “ARC”)Use ARC and%retic x RBC to get the whole pictureif pt has retic of 1% (normal) that’s fine unless their Hg is low, then retic should be high and compensating.
two classifications and 3 sub classifications of anemia
PATHOPHYSIOLOGIC: * decreased production * blood loss * increased destruction MORPHOLOGIC * Macrocytic * Normocytic * Microcytic
What are disorders with destruction probs
HemoglobinopathiesRBC Membrane defectsenzyme deficiencies
What is RBC chromicity
clues on [Hg] : color or RBCcentral palor: normalMCH, MCHC can give clues, but Peripheral blood smear is more importanthyperchromic, normochromic, hypochromic, or polychromasia
What diseases are connected with these shapes, and what are these RBC shapes:Target cells,echinocyteAcanthocyteSpherocyte
Target cells: looks like a target: liver disease, HbC, HbD, HbE, Thalassemiaechinocyte: spiney like a sea urchin: Uremia, hypokalemia, artifactAcanthocyte: irregularly shaped RBC withthorny projection:liver disease, PK deficiencySpherocyte: sphere shaped, no central palor: HS Immune hemolytic anemia
MicrocyticAnemia causes
Fe deficiency anemiathalassemias (alpha &beta)Chronic disease/ inflammationPb toxicicty
Most common anemia
Fe deficiency with 3% of young children in US8-10% have Fe deficiency with out anemia(pregnant women, adolescents, elderly)(if Fe deficient and small bodied, a small blood loss could push them over the edge to become anemic)
Etiology of Fe deficiency
Increased demand to make blood (infancy, adolescents, pregnant, making more rbcs)
malnutrition (vegetarians, vegans, junk food diets) decreased absorption (gastrectomy, H. pylori, IBD, drugs) GI bleeds benign or malignant, GU bleeding heavy periods, blood donors
drugs: NSAIDS, steroids chronic kidney disease, IBD, heart failure, obesity
Stages of Fe depletion, what labs would you order and why
1) Depleted iron stores (marrow iron/serum ferratin) 2-3+2) Iron deficient erythropoiesis: Serum Fe <100ug/dl and %saturation is <303) Iron Deficient Anemia: HCT<40, RBC become microcytic and hypochromic*don’t stop treatment too early, gotta build up stores! Serum Fe increases in one meal, Serum ferratin slower to build
What does low Fe look like with labs?
Low: Hg, MCV, MCH, MCHC, RBC countLowuncompensated retic countIncreased TIBC/transferin(nothing to bind them)Low ferritin (deficiency: <10-12ng/L, depletion: 12-20ng/Lnormal is 20-300ng/LInflammation can falsely elevate Ferratineven if you don’t have iron stores
Problems with Fe Tx
Ferous sulfate tasteshorrible.Side effects include dyspepsia, constipation, nausea, abd pain,Helps to take with food… decreases absorption, but some is better than not taking it at all.Polysaccharide preparationssweeter
Foods with high Fe
Liver, red meatbeans/ greensiron-fortified cereals/ grainsheme: meat, non-heme: vegetarian
therapeutic response to Fe treatment of deficiency
Tx works within 3 days. see less hypochromia, increased RDWincreased reticulocytes in 2-3 days,Hg & MCV goes up in a weekSerum iron 1-2 hrsTIBC goes down: 2-3 weeksSerum Ferritin goes up: 1-2 weeks, 3-4 to normal
Why are they having Fe loss in the first place? What would you look for?
GI Blood loss: guaiac (occult stool), if positive endoscopyUrea breath testTest Antibodies for H. pylori, anti-transglutaminase (celiac sprue if fails to respond to oral iron)C-reactive protein: inflammation? neoplasm? especially in elderlyMetro/menorrhagia: evaluate for bleeding disorder
Normal Treatment for Fe deficiency
Iron Salts 100-200mg elemental Fein 2 dosesFerrous Sulfate, Ferrous GluconateTaken on empty stomach for best absorption,avoid coffee, tea, take with Vit C (acid helps absorption)Kids: 2-6mg/2 doses, NO MILKcontinue Tx 3mths to replenish serum ferritin*
when oral Fe is contraindicated, or another method is indicated
IViron therapy : for those who can’t take orally (gastrectomy, duodenal bypass, H. pylori, celiac, IBD, genetic IRIDA, or if needs to be immediate recovery (severe anemia in 2nd-3rd trimester, chronic renal disease, substitution for blood transfusion (religious reasons), chemo anemia (from ESA)contraindicated:1st trimester of pregnancy, iron allergy (hypersensitivity rx)
What is anemia of Chronic Disease
Anemia from a chronic state of inflammation(like cancer, chronic infection, lupus, RA, and other autoimmune disease, obesity, aging)that causesimpaired production of RBCs
What’s the pathophysiology Anemia of Chronic Disease that has to do with iron levels?
Hepsiden ( regulatory hormone made in liver, excreted to urine) tells Macrophages to keep iron inside cells, and not let it into circulation, andtells duodenal and intestinal cells not to absorb more Fe. This is because it thinks it is being invaded, and Fe makes bacterial infections stronger.We expect higher hepsiden in Fe overload, and infection
lab findings in Anemia of Chronic Disease
mild-moderate anemiaMCV: normal to lowRDW: normalRetic Count: lowFerritin: normal tohigh (even if Fe is low)
treatment Anemia of Chronic Disease
- eradicate underlying disease if impossible,
- transfusions
- IV iron
- ErythropoesisStimulating Agents
- New experimental approaches targeting IL-6 activity
What is macrocytic Anemia? what’s it caused by
Larger RBCsCaused by B12 or Folate deficiency (DNA synthesis: mismatch between how much cytoplasm to put in cell and membrane so cells larger)Non-Megaloblastic causes: Phentoin, Bactrim, ART, Chemo, hypothyroid, liver disease, alcoholics, myelodysplasia, bone marrow failure, reticulocytosis
What labs do we order if we suspect Macrocytic Anemia?
CBC with peripheral blood smear (hyper-segmented neutrophils/neutropenia)reticulocyte count (to see if MCV 110-140 is bigger because more retics, also to see if production or destruction prob)serum cobalamin, folate, and TSHliver function test (alcoholics)measure folate/cobalamin (needed for DNA synthesis including for RBCs)
Signs and symptoms of macrocytic anemia
Both for B12 and Folate deficiency, see glossitis-smooth tongue, and dyspnea with exercise, pallor, etc.For B12, neuropathies, ataxia, seizures, psychiatric probs, decreased sensations
what causes B12 deficiency
pernicious anemia: (autoimmune) disease where autoantibodies destroy gastric parietal cells which produce intrinsic factormalabsorption: IBS, chrons disease, celiac, bowel resectionHemolytic anemia, excess blood losspregnancy: when more need is happening
Lab results for Macrocytic Anemia from B12 deficiency
moderate -severe anemiaelevated MCV 110-140low reticulocyte (not compensated)hypersegmented neutrophils and macroovalecyteson smearmild thrombocytopenia and/or neutropenialow serum B12, <170 (when normal or 170-210, confirm with elevated methylmalonic acid or homocystine)
Diagnosis for Pernicious Anemia
Anti-intrinsic factor antibodies (100%specific, but only 70%sensitive= false neg)Anti-parietal cell antibodies (more sensitive, but less specific=false positive)Shilling test (board answer)
Tx for B12 deficiency
IM or subcutaneous injection of 100mcg B12daily x 1 wk, then weekly x 1 month, then monthly for lifeORsublingual 1mg/day for EVER(folic acid also recommended for first few mths of B12 tx)
Response to B12 Tx for Macrocytic Anemia
well-being in 1-2 days,brisk retic increase in 3-4 days, and Hg in 10 daysHypokalemia can occur during early response because increased K+ use for RBC production monitorneuropathies improve totally by 6 mths
Labs for Folate Deficiency
Mod-severe anemiaelevated MCVlow retichypersegmented neutrophils/macro-ovalcytes on peripheral smearmild thrombocytopenia/neutrophilsRBC folic acid levels (better than serum folate b/c reflects body stores <150 is deficient)also measure B12.
Tx of folate deficiency
daily oral folic acid 1 mgResponse is rapid wellbeingretics in 5-7 daystotal correction of hematologic abnormals in 2 mths
Non-megaloblastic anemia causes and Tx
anti-retroviral drugs, antiseizure meds, chemo, bactrimhypothyroidismnon-alcoholic liver diseasechronic alcohol use: stop alcohol use, blood returns rapidly
Differential for Normocytic Anemia
+++Reticulocyteshemolytic anemiaPost-hemorrhagic anemia—Reticulocytesacute hemorrhageanemia of inflammationrenal/liver diseasemarrow infiltrationmyelodysplastic syndrome
most common causes of inherited hemoglobin disorders
DNA deletions or point mutations
what is a quantitative hemoglobin disorder
thalassemia
what is a qualitative hemoglobin disorder
hemoglobinopathy
normal fetal hemoglobin made of?
2 alpha chains and 2 gamma chains
normal adult hemoglobin made of
2 alpha chains and 2 beta chains
in thalassemia what is the balance of alpha and beta chains
alpha thalassemia- excess betabeta thalassemia- excess alpha
pathophysiology of thalassemia
excess globins precipitate and damage the RBC membrane, ineffective erythropoiesis
outcomes of thalassemia
anemia, bone marrow expansion, extramedullary hematopoiesis, increased intestinal iron absorption
Sickle cell and thalassemia protects from what disease?
malaria
silent carrier in thalassemia
one deletion of the functional gene
What is alpha-thalassemia trait
two deletions of functional genes ( cis- more common in Asian pops or trans more common in African pop)
HbH disease
3 deletions of functional genes
hydrops fetalis
4 deletions of functional genes- incompatible with life
alpha thalassemia trait definition
reduced alpha globin chain synthesis due to 2-gene deletion- causes an excess amount of gamma globin at birth, or beta globin as an adult
best time to identify alpha thalassemia
in newborns- excess gamma globin and fast band production makes it more identifiable with testing. For adults, try to track newborn screen.
Heinz bodies
detects protein precipitates, denatured proteins. Test isnot commonly used due to common false negatives
treatment for hydrop fetalis
if caught in utero- can do transfusion support.then stem cell transplantation to treat after birth.
beta thalassemia
beta-0- producing no beta globinbeta+ produces little beta globin
B-thalassemia major
homozygoussevere anemiarequires life-long RBC transfusion
B-thalassemia intermedia
mild anemiaoccasional transfusions required
B-thalassemia trait
heterozygousasymptomaticconfused with iron deficiency- suspect if patient does not respond to iron therapy
phenotypes for b thalassemiamild moderate severe
B+ B+Bo B+Bo Bo
beta thalassemia trait under the microscope
unbalanced a:b chainselevated A2elevated Hb Fmicrocyctic anemia
treatment of beta thalassemia intermedia
hydroxyurea- increase in fetal hemoglobin production.watch iron absorption- can be increased
outcomes of thalassemia major/erythropoiesis
expansion of marrow cavities, extramedullary hematopoiesis, splenic destruction of RBC, hypersplenism, growth failure
treatments for thalassemia major
hypertransfusion every 2-4 weekssplenectomy (in non-transfusion dependent)stem cell transplant to curetreat iron overload with chelation
iron overload cause
RBC trasfusionsno body mechanism to get rid of excess ironintake of 1 gm/month in chronic transfusion patients
iron overload complications
pericarditis, arrhythmias, cardia failurefibrosis, cirrhosis, hepatic failure, cancerdiabeter, growth failure, infertility
how to test for iron overload
serum ferritin, liver biopsy, MRI
treatment of iron overload
chelation (deferasirox or deferoxamine)- start treatment early to prevent iron overload rather than trying to reduce amount of iron in the body if possible. phlebotomy- regularly remove blood to reduce amount of iron in the blood
sickle cell disease definition
group of blood disorders containing HbS
is sickle cell dominant or recessive?
autosomal recessive
sickle cell pathophysiology
single point mutation on the beta chainAdenine to Thymine at position 6 of the beta globin.changes RBC shape (stiff due to deoxygenation)blood flow obstruction leads to ischemia
epidemiology of sickle cell
in US- 8%1/400 births3,000,000 with trait and 100,000 with diseaseglobally more than 400,000 births per year
how does sickle cell trait protect against malaria
lower transmissionreduced parasitemiadecreased mortality
how is sickle cell diagnosed in the US?
all newborns tested with dried blood spotsmost common disease found by newborn screening
newborn screening resultsFA
normal
newborn screening resultsFAS
sickle cell trait
newborn screening resultsFS
sickle cell anemia
newborn screening resultsFSA
sickle B+ thalassemia
newborn screening resultsF
thalassemia major
newborn screening resultsFA
fast band- alpha thalassemia trait
risks for sickle cell trait
hematuriarenal medullary carcinomasudden death during prolonged, strenuous physical activity
hyphema
increased occular pressure, loss of visionthose with sickle cell need referral to a specialist to prevent loss of vision
clinical manifestations of sickle cell disease
functional asplenia, pneumococcal infectionhemolysis (partially compensated- increased reticulocytes)acute vaso-occlusive events (painful)organ damage
most common cause of death for sickle cell disease patients
organ damage- spleen, kidneys, lung, brain, eyes, hips
how to prevent sepsis in newborns with sickle cell disease
prophylactic therapy with oral penicillin by 3 months
penicillin regimen for sepsis prophylaxis with sickle cell
125mg BID- until age 3250mg BID- until age 5usually has to be refridgerated and picked up every 2 weeks from the pharmacy- difficult to get patients to be compliant
why stop prophylaxis at age 5
immunizations with HiB, prevnar, pneumovax, meningovax, no evidence of sepsis prevention beyond age 5
what temperature is considered a medical emergency for patients with sickle cell disease?
38.5 or greater
what to order in a SCD patient with fever
labs- blood cultures, cbc with retic, UAchest x-raytype and cross-match if increased pallor or splenomegaly or resp/neuro symptoms
treatment of sepsis in SCD patients
IV broad spectrum antibiotics
most common manifestation of SCD
acute vaso-occlusive pain- occurs as early as 6 months
painful events with SCD
sudden onset in extremities, back , and sternum/ribsdactylitis/ hand-foot syndrome
treatment of painful events
NSAIDs and opioidsfluids and hydrationearly pain control
warning signs with SCD pain
respiratory distress, chest pain- acute chest syndromefever- infectionweakness- strokelethargy- splenic sequestrationabdominal pain/jaundice- cholelithiasis
symptoms of acute splenic sequestation
tender splenomegaly, worsened anemia, increased retics, platelets less than 150,000, LUQ pain, SOB, vomiting
typical age of onset of acute splenic sequestation
6 months to 3 years
treatment of splenic sequestration
RBC transfusionscareful not to overshoot
recurrence rate of splenic sequestration
50%
acute chest syndrome signs/symptoms
+/-fever, dyspnea, pain, hypoxia, increased WBC, pleural effusion, fat embolism, atelectasis, sickling and intra-pulmonary sequestration
acute chest syndrome treatment
admissionantimicrobial treatment- ceftriaxone, azithromycin, levofloxacinO2bronchodilatorsIV fluidstransfusions
avascular necrosis (AVN)
osteonecrosis in limited circulation areasfemoral head most common
AVN treatment
NSAIDs, PT, hip replacement
SCD and renal manifestations
hyposthenuriarenal infarctionprogression to renal failure and proteinuria
priapism
prolonged, painful erection40% of men with SCDblood flow is obstructed
priapism treatment
analgesics and hydrationaspiration if greater than 4 hoursvasodilators can prevent attacks, but do not treat
sickle retinopathy
vitreal hemorrhage and retinal detachmentcauses vision lossseen in HbSC > HbSS
leg ulcers and SCD
5-10% of people > age 10 have healing problems
incidence of stroke with SCD
11% by age 20 24% by age 45
stroke symptoms
hemiparesis (weakness as opposed to pain)visual/language dysfunctionseizuresheadachesaltered sensationaltered mental status
treatment of stroke with SCD
transfusion immediatelyCTIV fluidsMRI (can wait a few days)
stroke recurrence with SCD
47-93% without treatmenttreat with blood transfusions every 3-4 weeks10-20% still experience recurrence with treatment
stroke prevention in SCD
transcranial doppler (TCD) ultrasonography screeningif > 200 cm/sec- abnormal, requires transfusions
indications for simple transfusions
splenic sequestrationtransient aplastic crisisanaemiaacute chest syndromepre-ops
indications for chronic transfusions
clinical strokeabnormal TCD (>200 cm/sec)multisystem organ failure
What are the signs and symptoms of platelet bleeding (i.e., primary hemostasis)?
- mucouos membrane bleeding
- epistaxis
- prolonged oozing from minor wounds
- brusing
- menorrhagia
- abnormal intraoperative bleeding
What is thrombocytopenia?
low platelet counts
What is a failure of secondary hemostasis?
- bleeding from large vessels
- subcutaneous hematomas
- hemarthroses
- intramuscular hematomas
This is a more “coagulation factor deficiency” picture
What are some signs of congenital thrombocytopenia?
- umbilical cord stump bleeding
* bleeding after circumcision that won’t stop
When you see bruising on a person with suspected thrombocytopenia, what distinguishes it from ordinary bruising?
- indurated (hardened)
- found in locations where simple trauma bruises are unlikely (e.g, abdomen)
- sometimes accompanied by petechiae
What arethe etiologiesof thrombocytopenia?
Poor platelet production * bone marrow failure * infections * drugs (sulfa) * nutritional disorders (B12, folate) * inherited Increased destruction of platelets * splenomegaly * non-immune mediated (DIC, HUS) * immune-mediated platelet destruction
What do normal platelets look like?
- purple color
- small (much smaller than RBC)
- little fuzzy granulations
- count and multiply in a field by 10k to get total
What is immune thrombocytopenia (ITP)?
immune system mediated destruction of platelets.
What do the practice guidelines from ASH 2011 say about treatment of ITP?
- mild symptoms (i.e., no “wet” bleeding) can be treated with observation alone
- First line treatment includes corticosteriods, IVIG or anti-D immunoglobin
- Adults: consider for platelet less than 30x109/Ltry corticosteriods first, IVIG if rapid or IVIG/Anti-D if you can’t do steroids
- Kids: probaby will use IVIG/Anti-D FIRST as corticosteroids can MASK underlying Leukemia and hide the diagnsosis from you.
What are the pratical considerations in treating ITP?
- no bright line rules for platelet levels Individualize decisions based upon:
- patient age (little people are dangerous)
- clincal symptoms
- platelets
- parent/your concern
- access to medical care (ER)
- Patients at high risk of significant bleeding should be treated and monitored
What are the symptoms of TTP?
- Note: Rare (congenital < acquired)
- “Classic” Pentad: thrombocytopenia; microangiopathic hemolytic anema; fluctuating neurological signs; renal impairment; fever.
- Most patients present WITHOUT the full pentad