Module 6 ICS 2

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Define anemia.: A reduction in the total number of RBCs, amount of Hb in the circulation, or circulating RBC mass
General causes of anemia?: 1. decreased RBC production

2. increased RBC destruction or loss
What is the physiologic result of anemia?: Impaired oxygen delivery gives rise to physiologic consequences secondary to tissue hypoxia as well as compensatory mechs to correct anoxia
Criteria for anemia in adults?: RBC x 10(12)/L <4.0 <4.5

Hb (g/dl) <12 <14

Hct (%) <37 <40
Compare and contrast normocytic, microcytic, and macrocytic RBCs.: Based on Mean Corpuscular Volume (MCV) --

normocytic: 80-100fl

microcytic: <80fl

macrocytic: >100fl
What is RDW?: Red cell distribution width.

-- a measure of RBC size variability, or ANISOCYTOSIS
-- anemic d/o's can be classified on the basis of RDW
When is RDW more often elevated?: Iron deficiency anemia

(less likely in thalassemia or anemia of chronic disease)
What is RPI? What does it measure?: Reticulocyte count/Retic productions index
-- percentage of total RBCs that are reticulocytes

Measures: bone marrow productivity
What are reticulocytes?: young RBCs, newly produces
-- distinguishable by their gray-pink color on smears
-- show a network (reticulum) of blue granules when stained w/ special stains like Methylene Blue
Symptoms of slow anemia vs. acute anemia?: SLOWLY -- few symptoms since the homeostatic mechs provide remarkable adaptation

ACUTE -- weakness, fatigue, palpitations, lightheadedness
Blood loss in a "typical" menstrual cycle?: 45-50ml
What drugs may induce BM suppression? Hemolytic anemia? GI bleeding?: PREDICTABLE BM SUPPRESSION: cancer chemo drugs

IDIOSYNCRATIC BM SUPPRESSION: chloramphenicol

HEMOLYTIC ANEMIA: penicillin

GI BLEEDING: ASA, NSAIDs, recreational drugs
Name some concurrent illnesses in which pts may experience anemia: chronic infections
inflamm disease
malignancies
HIV
renal or hepatic failure
endocrine d/o's
How can eating habits cause anemia?: 1. Folic acid deficiency due to poor dietary intake
-- anorexia assoc w/ cancer
-- elderly w/ severe depression
-- alcoholics w/ hx of binge drinking

2. post gastrectomy pts w/ achlorhydria
-- develop vitamin B12 malabsorption although anemia may take years to develop

3. food picas
What are the classic symptoms of anemia? Other indicators?: weakness
fatigue
dyspnea
palpitations
dizziness

-- jaundice and dark urine are indicators of hemolysis

-- dysphagia may be sign (esophageal webs)

-- gait or balance difficulties may signify the neuro disorder assoc w/ pernicious anemia
What are the classic physical finding with anemia?: pallor (skin, mucous mbrns)
tachycardia
postural hypotension

palmar creases appear pink in fully opened hand unless Hb is <7gm/dl -- useful guide to presence of severe anemia
What skin and mucous mbrn findings w/ anemia?: IRON DEFICIENCY
-- tongue can be devoid of papillae and sore
-- koilonychia (spoon shaped fingernails)

PERNICIOUS ANEMIA
-- jaundice - "lemon yellow" tint due to simultaneous pallor and jaundice
-- can also have tongue completely devoid of papillae that is often also sore

ACUTE LEUKEMIA
-- gingival hypertrophy

LEAD POISONING
-- dark line of lead sulfide deposited in gums and at base of teeth
CV findings w/ anemia?: tachycardia
postural hypotension
flow murmurs
Spleen findings w/ anemia?: may be enlarged concomitantly w/ anemia due to:

-- primary hematologic disease - lymphoma, leukemia, autoimmune hemolytic anemia

-- secondary to infection, inflammation
Liver findings w/ anemia?: Exam liver size and for stigmata of chronic liver disease:
spider angiomata, gynecomastia, palmar erythema, testicular atrophy, caput medusae
Neurologic findings w/ anemia?: Vitamin B12 deficiency impairs:
central
olfactory
spinal cord
peripheral n fxn (especially vibratory and proprioception)

Severe chronic deficiency may lead to irreversible neuro dysfxn
List causes of hypochromic microcytic anemia.: MCV < 80fl

iron deficiency
thalassemias
lead poisoning
chronic disease
sideroblastic anemia
Blood smear cells seen in iron deficiency?: pencil (cigar) cells

high RDW

sometimes thrombocytosis
Typical labs of iron deficiency anemia?: â†“ iron

â†‘ TIBC

Fe/TIBC < 10%

â†“ ferritin

Confirm if necessary w/ BM stores (absent in iron deficiency)
Blood smear cells seen with thalassemias?: target cells
Typical labs of thalassemias?: confirm presence of target cells w/ Hb electrophoresis

high A2 ± F hemoglobins for B thalassemias
Blood smear cells seen w/ lead poisoning?: course basophilic stippling
Typical labs of lead poisoning: Confirm w/ lead level, free erythrocyte protoporphyrin
Blood smear cells seen w/ anemia of chronic disease.: More are normochromic
Typical labs of anemia from chronic disease?: â†“ Fe

â†“ TIBC

Fe/TIBC > 15%

â†‘ ferritin

BM iron stores increased and present in RE cells
Blood smear cells seen w/ sideroblastic anemia?: ringed sideroblasts demonstrated by Prussian Blue staining of BM RBC precursors
Typical labs seen w/ sideroblastic anemia?: â†‘ Fe

nl TIBC

â†‘ Fe/TIBC

â†‘ ferritin
List list causes of macrocytic anemia.: MCV > 100fl

B2/folic acid deficencies
Liver disease
Cancer chemotherapy
Blood smear of B12/folic acid deficiency would show?: pancytopenia

macroovalocytes

hypersegmented PMNs
Typical labs of B12/folic acid deficiency?: â†“ serum B12, RBC folate

â†‘ indirect bilirubin

â†‘ LDH

â†‘ uric acid

â†‘ serum iron

â†‘ Fe/TIBC

Helpful test to confirm PERNICIOUS anemia is anti-IF antibody -- highly specific but only positive in 75%
Treatment of B12/folate deficiency anemia?: usually responds rapidly and dramatically to B12 or folate

Schilling test best done 6-8 wks after B12 replacement to correct malabsorption due to megaloblastic GI epithelium
Blood smear of liver disease would show?: macrocytosis secondary to abnormal lipid composition in the RBC membrane

round macrocytes (as opposed to oval in B12/folate)

may also see target and/or spur cells (acanthocytes)
Blood smear of cancer chemo would show?: many cytotoxic drugs or antimetabolites used in chemo drugs impair DNA synth and produce a defect in hematopoiesis that resembles B12 or folate deficiency
Polychromasia/polychromatophilia?: reticulocytes
Target cells?: liver disease

hemoglobinopathies

post-splenectomy
Microspherocytes?: autoimmune hemolytic anemia

hereditary spherocytosis
Shistocytes?: fragmented RBCs seen in fragmentation hemolysis:

TTP

DIC

cardiac valve hemolytic anemia

malignant HTN

massive venous thromboembolism
Teardrops?: bone marrow infiltration:
- tumor
- infection (granulomas)
- fibrosis
Leukoerythroblastic blood smear?: refers to presence of both immature WBC and nucleated RBCs, often accomp by teardrop-shaped RBCs
-- correlates w/ highly infiltrative process of the bone marrow
Howell-Jolly bodies?: nuclear remnants seen in post-splenectomy patients
Sickle cells?: sickle cell anemia
Rouleaux formation?: "Rouleaux" are stacked RBCs caused by coating individ cells by charged proteins that neutralize the normally negative charge that by repulsion keeps RBCs from agglutinating

-- multiple myeloma when RBCs become coated by the + charged paraproteins
Describe how RPI classifies anemias.: RPI â‰¥ 2 favors destruction problem

RPI â‰¤ 2 favors production problem
Laboratory parameters of hemolysis include?: â†‘ indirect bilirubin
â†‘ LDH
â†“ haptoglobin

**haptoglobin can be low in liver disease where the problem is decreased synth, NOT hemolysis

** ineffective erythropoiesis seen in megaloblastic anemias can produce same chemical abnormalities so one must always have in mind clinical context
What does the Coombs test measure?: Antibodies bound to the RBC surface

-- direct Coombs test is (+) in autoimmune hemolytic anemia and hemolytic transfusion rxns
Disorders assoc w/ decreased production of RBCs?: renal failure
chronic diseases (infection, inflamm, malignant)
nutritional deficiencies
myelodysplasia ("pre-leukemia")
aplastic anemia/pure red cell aplasia
endocrine d/o's (thyroid, pituitary)
Disorders assoc w/ increased destruction of RBCs?: hemolytic transfusion rxn
infections
immune hemolysis
RBC fragmentation
Hereditary spherocytosis
Hemoglobinopathies
Hypersplenism
RBC enzyme defects
PNH
Miscellaneous (burns, drowning)
Clinical use of blood transfusions?: RBC transfusion is always symptomatic and supportive rather than definitive therapy for anemias
-- only use when no definitive trtmt for the underlying cause OR when severity and clinical manifestations deem necessary

**signif risks incl allosensitization, transfusion rxns, infection transmission, iron overload
Iron deficiency may occur as a result of...?: inadequate dietary intake
-- almost exclusively problem of infants and children and of pregnancy and lactation
malabsorption (duodenal)

chronic blood loss

OR combination of above
In an adult, Fe deficiency is almost always assoc w/...?: blood loss
In pregnancy, the avg iron loss totals about...?: 900mg

diversion of Fe to fetus, blood lost at delivery and lactation
Preferred mode of iron therapy?: oral route -- most economical, highest dosage, most safely, in readily assimilated form (ferrous sulfate FeSO4)
Approp dose of oral iron prep?: should provide 150-200mg of elemental iron/day

Usually 3-4 tablets per day

Ex: one 320mg FeSO4 tablet contains 66mg elemental Fe
How soon can we achieve normal RBC parameters after beginning treatment?: usually after 6 wks (if no concurrent blood loss)

continue therapy for 4-6mos to ensure full replacement of total body iron stores
When is parenteral iron indicated?: rarely indicated

- patients whoh cannot absorb oral iron
- patients unable to follow instructions or comply w/ oral therapy

**frequency of systemic rxns high
Approach to megaloblastic anemia?: pending definitive dx, empiric B12 and folate therapy can be initiated w/o harm

Once dx established, consider possible etiologies.
Etiologies of B12 deficiency?: Nutritional - vegans
Pernicious anemia
Post-gastrectomy
Malabsorption
-- bacterial overgrowth
-- D.latum fish tapeworm
-- pancreatic insuff
-- tropical/nontropical sprue
-- Crohn's, intestinal lymphoma
-- transport d/o's
-- metabolic d/o's (rare)
Etiologies of folate deficiency?: nutritional causes
-- decreased intake
-- increased requirement: pregnancy, lactation, hemolysis

malabsorption
Describe the B12 treatment.: 1. daily injections of 100μg for 5-7 days THEN
2. weekly injections for 3-4 weeks THEN
3. 1000μg monthly for life

Correction is rapid: BM abnormalities corrected w/in 24-72h and reticulocytosis occurs by 4-6d

Rapid reversal of ineffective erythropoiesis by B12 causes rapid cellular uptake of K and may result in severe hypokalemia -- monitor levels

Reversal of neuro manif is unpredictable and variable; persisting >6mos likely permanent
Describe the folate treatment.: oral folic acid 1mg daily

course of response similar to B12 deficiency

duration depends on clinical situation
What if pt does not respond to B12 or folate?: evaluate for concurrent iron deficiency
What is DIC?: Disseminated Intravascular Coagulation
-- occurs when coag system is activated by generation of excessive thrombin in the circulation

Catastrophic bleeding d/o characterized by:
-- depletion of procoag factors
-- thrombocytopenia
-- activation of fibrinolytic system
Causes of DIC?: obstetrical complications
- retained dead fetus
- absorption placentae
- amniotic fluid embolism

septic shock
trauma
cancer
How is DIC anemia characterized?: fragmentation hemolysis
-- schistocytes present in circulation
DIC Dx?: Prolonged PT, PTT, and TT

Presence of fragments of cross-linked fibrinogen (d-dimer) in circulation

Presence of fibrin/fibrinogen fragments (fibrin degradation products, FDP) in circulation
DIC Tx?: address underlying cause

supportive care of blood, platelets, plasma transfusion
What is TTP?: Thrombotic thrombocytopenic purpura

Characterized by:
-- microantiopathic hemolytic anemia (fragmentation hemolysis)
-- thrombocytopenia
-- fever
-- renal manifest
-- neuro manifest

May present as isolated syndrome or can be assoc w/ infection, malig, meds, vasculitis, preggers, etc.
Pathogenesis of TTP?: related to absence of vWF cleaving protease activity
-- abnormally large vWF multimers in circulation
-- platelet hyperaggregability
TTP Dx?: clinical picture

hemolysis w/ plentiful schistocytes

coag studies are NORMAL
TTP Tx?: plasma exchange -- removes unusually large vWF multimers and provides missing protease activity

corticosteroids

**platelet transfusions CONTRAINDICATED b/c can contribute to disease progression
What is AIHA?: Autoimmune hemolytic anemia

-- may be primary (25%), secondary (60%) or drug induced
-- secondary assoc w/ systemic immunologic d/o's like SLE, cancer, or infection
Pathogenesis of AIHA?: binding of autoantibodies ± complement to the RBC surface and destruction of coated RBCs in the spleen

-- 75% of RBC autoantibodies are IgG and react w/ RBC at 37C (warm autoantibodies)
-- 25% are IgM and react at temps <37C (cold agglutinins)
Characteristic cell of AIHA?: microspherocyte
Warm agglutinin AHIA Tx?: directed toward eradication of autoantibody and/or reduction of RBC rate of destruction

1. corticosteroids (DOC)
-- 75% respond, but half relapse when tapered off

2. splenectomy (TOC) for pts who fail (1)
-- removes major site RBC destruction and source of autoAb production
-- 2/3 have beneficial response to splenectomy

3. Fail to respond to (1) and (2) -- try other immunosuppressive agents, macrophage poisons, RE blockade w/ IV Ig
-- use of synth androgen, danazol, may prove useful
Cold agglutinin AHIA Tx: frequently have assoc malignancies or infect diseases
-- direct Tx toward underlying dz

**corticosteroids and splenectomy are relatively ineffective
**cold avoidance may be addtnl impt aspect of dz management

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